South Bay Geotechnical Review

South Bay Geotechnical Data (Including South End, Fort Point, Roxbury, and South Boston)

Disclaimer: This is a collection of research notes and images accumulated and published while preparing the Feb. 23 2026 Petition/Notice. At some point I intend to come back and merge, organize, annotate, etc. but until then, I at least wanted to make some of the references and data I found during my investigation publicly available. -AG

SOUTH BAY RESEARCH NOTES & RESOURCES:

GEOLOGY & GEOGRAPHY:

ENGINEERING, SAFETY, & REGULATORY: 

1795-1895 Wharf Lines

1630 Shoreline

Investigation of Subsoil and Foundation Conditions, Boston Redevelopment Authority, South End Project Mass. R-56, South End Urban Renewal Area (December 27, 1963)

MA Official State Geological Map

"The Neck"

"During the 1700’s this area, known then as Gallows Cove, operated as a thriving maritime center capable of handling vessels of all descriptions engaged in world commerce. The land expansion of Boston Proper, South Boston and Dorchester combined with requirements for increased wharfage succeeded in reducing the waterway to a relatively narrow channel. Progress, in the nature of bridge crossings, for land transportation, limited the movement of large sailing vessels causing owners to seek more accessible berthing facilities. The merchants relocated their operations to follow suit thus initiating the decline of the area which has continued unchecked to the present state of dilapidation.

1959 Senate Bill 0498. Report of the Special Commission Relative to Filling and Improving South Bay and Part of Fort Point Channel in the City Of Boston: A Comprehensive Report for the Filling and Improving a Portion of Fort Point Channel and South Bay. (1959).

By 1708 Boston and Charlestown had 78 wharves. Long Wharf, which provided direct access for sea going ships, was opened in 1713 and became the focus of shipping activities."
FINAL ENVIRONMENTAL IMPACT STATMENT ON DEBRIS REMOVAL FROM BOSTON HARBOR, MASSACHUSETTS, U.S. Army Corps of Engineers (1980).

The Neck was, in the words of William Muir Whitehill “a mangy kind of natural causeway, soggy at high tide and spray blown in a storm, that leads to a fortified gate at what is now Washington and Dover Streets. This is the only means of approaching by foot or horse. All other routes require boats. As it is made no more exhilarating by the presence of a gallows just outside the town gate, and as it leads through the least settled portion of the town, we will gain a more favorable impression by choosing to approach Boston from the sea... So forlorn was the Neck that even the street leading from it into town had no official name until the eighteenth century. Bartholomew Green’s broadside of 1708 identified the highway described in 1650 as “the High wayes from Jacob Eliot’s Barne to the Farthest gate bye Roxbury Towns end” as Orange Street.
Walter Muir Whitehill, Boston: A Topographical History

Mr. "William Wood, who was in Lynn, Boston, and perhaps in the Plymouth Colony, very early after the first settlement of the country.... "A quarter of a mUe to the North-side of the Towne, is another River called Stony-river; upon which is built a water-mUne. Here is good ground for Corne, and Medow for Cattle : Vp westward from the Towne it is something rocky, whence it hath the name of Roxberry; the inhabitants have faire houses, store of Cattle, impaled Corne-fields, and fruitful! Gardens. Here is no Harbour for ships, because the Towne is seated in the bottome of a shallow Bay, which is made by the necke of land on which Boston is buUt; so that they can transport all their goods from the Ships in Boats from Boston, which is the nearest Harbour. " Boston is two miles North-east from Roxberry: His situation is very pleasant, being a Peninsula, hem'd in on the South-side with the Bay of Roxberry, on the Northside with Charles-river, the Marshes on the backe-side, being not halfe a quarter of a mile over, so that a little fencing will secure their Cattle from the Woolues. Their greatest wants be "Wood, and Medow-ground, which never were in that place; being constrayned to fetch their building-timber, and fire-wood from the Hands in Boates, and their Hay ia Loyters : It being a necke and bare of wood: they are not troubled with three great annoyances, of Woolves, Eattle-snakes, and Musketoes. These that live here upon their Cattle, must be constrayned to take Farmes in the Countrey, or else they cannot subsist; the place being too small to containe many, and fittest for such as can Trade into England, for such commodities as the Countrey wants, being the chiefe place for shipping and merchandize. " This neclce of land is not above foure miles in compasse, in forme almost square, having on the south-side at one corner, a great broad hill, whereon is planted a Fort, which can command any ship as shee sayles into any Harbour within the still Bay. On the N"orth-side is another Hill, equall in bignesse, whereon stands a Windemill. To the IS^orth-west is a high Mountaine with three little rising Hils on the top of it, wherefore it is called the Tramxmnt. From the top of this Mountaine a man may over-looke all the Bands which lie before the Bay, and discry such ships as are upon the Sea-coast. This Towne although it be neither the greatest, nor the richest, yet it is the most noted and frequented, being the Center of the Plantations where the monthly Courts are kept. Here likewise dwells the Governour: This place hath very good land, affording rich corne-fields, and fruitefuU Gardens ; having likewise sweete and pleasant Springs. The inhabitants of this place for their enlargement have taken to themselves Farme-houses, in a place called Muddy-river, two miles from their Towne; where is good ground, large timber, and store of Marsh land, and Meadow. In this place they keepe their Swine and other Cattle in the Summer, whilst the Come is on the ground at Boston, and bring them to the Towne in Winter."
A TOPOGRAPHICAL HISTORICAL DESCEIPTION BOSTON. BT NATHANIEL B. SHURTLEFF. BOSTON: PniNTBD BT BEQUEST OF THE GITT COUNCIL. 1871

When the Count de Kochambeau was sent in 1780 from France with six thousand men to the assistance of the United States in the war of the revolution, in which he did great service at the siege of Yorktown, he had among his chaplains the Abbe Robin, a person of considerable culture and judgment, who in a series of thirteen letters to a friend, gave a very discriminating account of his travels through the country. "At twenty-five years of age, the women begin to lose the bloom and freshness of youth; and at thirty-five or forty, their beauty is gone. " The decay of the men is equally premature, and I am inclined to think that life itself is here proportionably short. I visited all the burying grounds ia Boston, where it is usual to inscribe upon the stone over each grave, the names and ages of the deceased, and found that few who had arrived to a state of manhood, ever advanced beyond their fiftieth year; fewer still to seventy, and beyond that scarcely any."
A TOPOGRAPHICAL HISTORICAL DESCEIPTION BOSTON. BT NATHANIEL B. SHURTLEFF. BOSTON: PniNTBD BT BEQUEST OF THE GITT COUNCIL. 1871

Jakotheb Frenchman, sometimes known as "J. Hector St. John, a farmer in Pennsylvania," and sometimes as " M. St. John de Creve Coeur," wrote during the years 1770 to 1786 an account of his residence in the United States, "The reader will see, that this town, one of the most ancient in America, and which contains from twenty to five and twenty thousand inhabitants, is built upon a peninsula in the bottom of a large bay, the entrance- of which is difficult, and in which he dispersed a number of islands, that serve still further for its defence it is only accessible one way on the land side, by a long neck or tongue of land, surrounded by the sea on each side, forming a sort of causeway. To the Northward of the town is another peninsula, which adheres to the opposite shore by a very short rock [neck}, and on this peninsula is an eminence called Bunker'sHill, at the foot of which are the remains of the little town of Charles-town. Cambridge is situated at the north-west, about two miles from Boston, but to go there in a right line, you must cross a pretty considerable arm of the sea in which are dangerous shoals, and, upon the coast, morasses difficult to pass, so that the only communication between the whole northern part of the continent, and the town of Boston is by the ferry of Charlestown, or that of Winissimet. The road to Cambridge lies through the field of battle of Bunker's hill."
A TOPOGRAPHICAL HISTORICAL DESCEIPTION BOSTON. BT NATHANIEL B. SHURTLEFF. BOSTON: PniNTBD BT BEQUEST OF THE GITT COUNCIL. 1871

On the south side of the harbor are the towns of Hull on the east, then, in succession southwesterly, the towns of Hingham, "Weymouth, Braintree (now Quincy), Dorchester and Roxbury, —for these last-mentioned towns should not be forgotten as having existed as distinct municipalities ; and that South Boston in the olden time was a part of Dorchester, under the name of Dorchester Point or Neck, and Roxbury or Gallows Bay (now South Bay) was once part of the harbor.
A TOPOGRAPHICAL HISTORICAL DESCEIPTION BOSTON. BT NATHANIEL B. SHURTLEFF. BOSTON: PniNTBD BT BEQUEST OF THE GITT COUNCIL. 1871

Captain Nathaniel Uring, in his account of his visit to Boston in 1710, printed in London in 1726, says : —" The Neck of Land betwixt the city and country is about forty yards broad, and so low that the spring tides sometimes wash the road, which might, with little charge, be made so strong as not to be forced, there being no way of coming at it by land but over that Neck."Whether what constituted old Boston was at one time an island, or was becoming one by the wasting forces of the elements, is a n interesting question for geologists. We know that for nearly a hundred and fifty years scarcely any change had taken place in the appearance of the Neck ; but the action of the town authorities seems to indicate a fear that its existence was seriously threatened. Within the recollection of persons now living the water has been known to stand up to the knees of horses in the season of full tides at some places in the road, on the Neck. The narrowest part was naturally the most exposed, as it was the most eligible also for fortifying. At some points along the beach there was a good depth of water, and Gibben's shipyard was located on the easterly side a short distance north of Dover Street as early as 1722, and as late as 1777. Other portions, on both sides of the Neck, were bordered by marshes, more or less extensive, covered at high tides. Wharves were built at intervals along the eastern shore, from' Beach to Dover Street. In front of these wharves dwellings and stores were erected, facing what is now Washington Street. Josiah Knapp's dwelling, formerly standing at the corner of Kneeland Street, was one of these, his wharf being so near the street that the passers-by complained that the bowsprits of h is vessels unlading there obstructed the highway. In the spring the road upon the Neck was almost impassable, especially before the centre was paved, which was from necessity done at last, "but with such large stones that the pavement was always avoided by vehicles as long as the old road was practicable. Measures began to be very early considered to protect the Neck from the violence of the sea. In 1 708 the town granted a number of individuals all the tract included within Castle and a point a little north of Dover Street, conditioned upon the completion of a highway and erection of certain barriers to "secure and keep off the sea." A second grant was made nearly eighty years later for a like purpose, extending from the limits of the first grant to a point a little beyond the former estate of John D. Williams, Esq., where the Cathedral now stands. From this beginning dates the reclamation of that extensive area now covered in every direction with superb public edifices or private mansions. A dike was built on the exposed eastward side, crossing the marshes to the firm ground on the Roxbury shore, before the Revolution, which traversed both the British and American works on the Neck. This followed in general direction the extension of Harrison Avenue. A sea-wall was built about the same time on the west side, for some distance south from the bridge at Dover Street, nearly as far as Waltham Street. In a word, the general appearance of the Neck eighty years ago, to a spectator placed at the Old Fortifications, was similar tov ^ the turnpikes crossing the Lynn marshes to-day, and was desolate and forbidding in the extreme, especially to a nocturnal traveller. From the old fortifications, northwardly, the highway was called Orange Street as early as 1708. Washington Street was named after the memorable visit of the General in 1789, and at first extended only from near Dover Street to Roxbury line ; the name was not applied to the whole extent of the present thoroughfare until 1824, when Cornhill, Marlborough, Newbury, and Orange became one in name as well as in fact.
OLD LANDMARKS AND HISTORIC PERSONAGES OF BOSTON By SAMUEL ADAMS DRAKE (1872, 1900)

Few of the thousands who daily traverse the Neck, with its elevated road, street-cars and private equipages following .each other in rapid succession, can realize that travellers were once in great danger of losing their way along the narrow natural causeway and its adjacent marshes. Yet so frequent had such accidents become that not only the town hut the General Court took action in 1723 to have the dangerous road fenced in.The Neck marshes were a favorite resort for birds, and were much frequented by sportsmen. It is related that Sir Charles and Lady Frankland one clay narrowly escaped being shot as they were passing over the highway. In 1785 the town of Roxbury was obliged to place sentinels here to prevent the desecration of the Sabbath. The meadows continued in much later times to be a resort for this purpose.The Neck was paved quite early in the last century, according to the fashion we have described elsewhere. In 1757 the General Court authorized a lottery to raise funds for paving and repairing the highway. The forty-two rods of Orange Street, mentioned as having been ordered paved in 1715, were probably the portion nearest the town, but it was paved in 1775 as far as the British works. The whole Neck was paved under the mayoralty of Josiah Quincy.
In colonial times the fortification which was raised a little south of Dover Street was tbe limit of the town, — all beyond was nearly in its primitive condition. In 1794 there were but eighteen buildings between Dover Street and the line. In 1800 there were not more than one or two houses from the site of the new Catholic Cathedral to Roxbury. The few buildings standing between the American and British lines were burnt during the siege, and only two barns and three small houses were then left on what was properly termed the Neck.A few doors north of Dover Street, on the easterly side of what was then old Orange Street, was the home of the favorite author and poet, Henry T. Tuckerman. The house was struck during the siege by a shot from the American lines. Mr. Tuckerman has contributed largely to our literature both in verse and prose, as an essayist, critic, biographer, and accomplished traveller. He was also well known through his articles in our leading magazines. As a poet, his " Rome " gives a good sample of his style. The only purpose of utility for which the Neck was formerly used, except perhaps the grazing afforded by the marshes along the causeway, was for brick- making. There were brickyards north of Dover Street, as well as south, before the Eevolution.These gave employment to many poor people during the continuance of t he Port Act. In this connection we may mentionthe total absence of building-stone of any kind on the site of original Boston. The principal elevations have been either wholly or partially removed without encountering a ledge of any description.
OLD LANDMARKS AND HISTORIC PERSONAGES OF BOSTON By SAMUEL ADAMS DRAKE (1872, 1900)

THE coastline of the Boston Lowland forms the shore of Boston Bay. Boston Harbor is a large estuary nearly cut off from the Bay by the peninsulas reaching out from the north and south shores (Index Map, Fig. i). On both these peninsulas are beaches several miles long. South of Boston proper lay, in colonial times, an expanse of marshland and mud flat, drained by winding creeks, which were part of the estuary of the Charles River. Further to the southeast we still find the hills of Dorchester and the low-lying coast bordering Boston Bay. Inland from this coast, the low areas may be either alluvial plains or swamps, and these are interrupted by rounded hills and slopes of till. The Boston Peninsula enjoyed other advantages than its favorable location between the rivers. Deep water on the harbor side permitted oceangoing vessels to land their freight and passengers easily. The land upon the slopes of Beacon, Copps, and Fort Hills was suitable for farming and, pasture. There was plenty of fresh-water in the swamps, such as the "Frog Pond" on Boston Common, and wells were easily dug in the gravel.
The Charles and Mystic Rivers were most important to the colonists as a means of communication with the interior. However these rivers were closed to deep water navigation by oyster banks which were located in their estuaries. These banks must have been large ones in 1634, f°r William Wood writes of the Mystic, "Ships without either Balast or loading, may float downe this River; otherwise the Oyster-banke would hinder them which crosseth the Channell." Concerning the Charles he says, "Ships of small burden may come up to these two Townes (Cambridge and Watertown), but the Oyster-bankes doe barre out the bigger Ships."3 The estuary of the Charles River, forming the western shore of the Boston Peninsula, broadens out into a wide, marshy bay before passing through a relatively narrow mouth into the harbor. This bay together with Fort Point Channel on the eastern shore of Boston proper forms the boundary of the Boston Peninsula (Fig. 1). Descriptions of the estuary and peninsula are many and they begin very early in the seventeenth century. A few years after 1621, when Miles Standish described Boston Harbor and the Mystic River,5 Europeans established permanent settlements in the Boston Lowland. Winsor, noting this description and others, says that Boston was connected with Roxbury by a "long narrow strip of land properly called 'The Neck' which, beginning to narrow just south of Eliot Street, stretched away like a ribbon of varying width to the mainland. Vastly different however, to its present aspect was its condition in those early days when the road which traversed it was well nigh impassable in the spring, when the horses waded knee-deep in water at full tides, when the only timber on the whole peninsula grew upon the Neck, and the marshes on either hand were the favorite hunting-ground of the sportsman." 7
There are several later references from which something of the nature of the Neck may be deduced. In addition to its being flooded by the "full tides," or Spring Tides (?), there were times when storms washed over the Neck, raising havoc with the city even as late as the middle of the nineteenth century. Perley8 has assembled several records of such storms and their accompanying high tides, one of which did considerable damage along Northampton Street. This region, southwest of Massachusetts Avenue, was, during early colonial times, part of an extensive marsh (Fig. 1).
Josselyn in 1663 9 mentions the existence of "marsh" northwest of the Neck (Fig. 1) and says, "Up higher (from Boston) in the Charles-River westward is a broad Bay two miles over, into which runs Stony-River and Muddy-River." The marshes and bay were variously named, until finally the region became known as "The Back Bay," the name which is now applied to the district. The extent of the Back Bay has been indicated on numerous early maps, particularly those of the British Admiralty. In searching for reasons for the location and ranges of the many batteries about the Back Bay one is struck with the idea that, although the Bay was composed of flats and marshes, it may have been possible to move across it in order to approach the Neck and the west side of the peninsula. The conventions on the maps also show that probably there were drainage channels or small creeks which would float small boats at the proper tide.
3 Wood, 1634, pp.41, 42. 4 Josselyn, 1663, p. 127. 6 Winsor, 1880, Vol. 1, p.63, et seq. 6 Wood, 1634, p. 39. 7 Winsor, 1880, Vol. 1, p. 531. 8 Perley, 1891. 9 Josselyn, 1663, P- I27« 10 Bruce, 1940.
Johnson et al., The Boylston Street Fishweir, Part 1.

The composition of the Neck, which, with the colonial marshes, connected Boston proper with the mainland, is puzzling. According to available borings, 14 the southern end, north of Waltham Street (Fig. i), is made up of "clay and rocks" and "hard clay." Where it widens out to meet the southern slope of Beacon Hill, i.e. south of Eliot Street, "hard, yellow clay" is recorded. The report "clay and rocks," which is only occasionally found in records of the local deposits and "hard clay," is not well differentiated from the records of blue clay which underlies the Neck. From this type of record it is impossible to do more than guess about the characteristics of the Neck… several statements in the literature which say that the Neck was built by tidal action. The most striking feature of the Neck is the narrow tongue projecting to the south of Eliot Street. It may properly belong with the whole extension beginning in the neighborhood of Boston Common. This feature, together with the swamps, i.e. the Frog Pond (Fig. i), and the swamp which once existed between Tremont and Eliot Streets, east of Park Square, are not characteristic of drumlins.
The southern end of the Neck loses itself in a marsh, as is shown on several colonial maps, for example, the Pelham map drawn in 1775. 16 It seems logical to assume that it was this southern section of marshland which was flooded during periods of high water and hampered colonial transportation between Boston and Roxbury. The location of sections of the marsh are recorded in several borings, as well as in Colonial records, and these are responsible for the location of the junction between dry land and the marsh at a point two hundred and fifty feet south of Waltham Street (Fig. 1).
This foundation ranges between eighty feet and 200 feet below tide level. The characteristics of the till, i.e. whether it is weathered or not, are not well known. According to W. O. Crosby this till is distributed on the sides of ancient valleys which have been cut in the bed rock. He believes that the absence of till in the bottoms of these valleys is evidence that glacial ice "continued to move along these lines after it had become stagnant on the uplands."20 Deposits, apparently lenticular in shape, of what seems to be till are found interstratified in the blue clay. These beds range from ten to twenty-five feet in thickness and are found, most frequently, near the bottom of the clay.
The Boston Lowland is dotted with fresh water swamps and, within the range of the tide, salt water marshes line the shores which are protected from the more violent erosive action of the sea. Both fresh water swamps and marine marshes produce peat. Peat varies greatly in thickness and consistency according to the complexity of local conditions. The principle deposit was an irregularly shaped marsh, the eastern margin of which was near Charles Street. The westernmost edge lay in the vicinity of Gloucester Street (Fig. i). Further extension to the west is suggested by a boring on Beacon Street, west of Massachusetts Avenue. The possibility that the bed extended to the east and north is suggested by one or two borings, particularly between Cambridge and Fruit Streets. The principle deposit was an irregularly shaped marsh, the eastern margin of which was near Charles Street. The westernmost edge lay in the vicinity of Gloucester Street (Fig. i). Further extension to the west is suggested by a boring on Beacon Street, west of Massachusetts Avenue. The possibility that the bed extended to the east and north is suggested by one or two borings, particularly between Cambridge and Fruit Streets. Borings in Fort Point Channel and a record from the Commonwealth Flats in South Boston,29 to the east of Boston proper, record the existence of beds which may well be Lower Peat. The possible extent of this bed has been indicated by the stippling in Figure I, but obviously it remains to be corrected by further investigations. A possible record of Lower Peat is found in one boring among several which were made in Mill Cove. The long strip of marsh running along the shore between Tremont and Washington Streets was reported by Colonial surveyors. Borings in this vicinity report areas of blue clay beneath this marsh but there are a few references to underlying silt.
Johnson et al., The Boylston Street Fishweir, Part 1.

"Prior to the Civil War, there were frequent demands to fill in both South Cove and Fort Point Channel to gain more buildable land. But but little activity occurred until 1828 when the Free Bridge was opened connecting South Boston to Boston."
BROADWAY BRIDGE, NPS, HISTORIC AMERICAN ENGINEERING RECORD, PHOTOGRAPHS WRITTEN HISTORICAL AND DESCRIPTIVE DATA, HAER No. MA-129, MA-135.

"Fort Point Channel is a channelized waterway separating downtown Boston from South Boston. Today, the water passage terminates in a culvert emerging from beneath the West Fourth Street Bridge. In the eighteenth century, this was a wide inlet leading to Roxbury Harbor, a large shallow body of water and mud flats fed by tides and creeks. On the west was the neck of the Shawmut Peninsula, and on the east were the farms of Dorchester Neck (now South Boston). In the nineteenth century, as South Boston and Roxbury developed, the Harbor underwent a series of use and name changes in response to a growing city. As South Cove, it became an urban fringe area, not only for Boston, but for the city of Roxbury and town of Dorchester (both of which were annexed to Boston after the Civil War). In the years immediately preceding and following the Civil War, coal yards and heavy industry took advantage of both rail and water connections to make the district a major industrial area. As commercial development spread along the Boston and South Boston shores, the channel leading to South Bay was narrowed. In the first half of the nineteenth century, the name "Fort Point Channel" was given to the water passage, after the promontory near Rowe's Wharf, east of Fort Hill."
BOS.9241, Fort Point Channel Bridge, ADDENDUM TO NEW YORK, NEW HAVEN & HARTFORD RAILROAD FORT POINT CHANNEL ROLLING LIFT BRIDGE, HISTORIC AMERICAN ENGINEERING RECORD, HAER MA-35 .

The Neck was, in the words of William Muir Whitehill “a mangy kind of natural causeway, soggy at high tide and spray blown in a storm, that leads to a fortified gate at what is now Washington and Dover Streets. This is the only means of approaching by foot or horse. All other routes require boats. As it is made no more exhilarating by the presence of a gallows just outside the town gate, and as it leads through the least settled portion of the town, we will gain a more favorable impression by choosing to approach Boston from the sea... So forlorn was the Neck that even the street leading from it into town had no official name until the eighteenth century. Bartholomew Green’s broadside of 1708 identified the highway described in 1650 as “the High wayes from Jacob Eliot’s Barne to the Farthest gate bye Roxbury Towns end” as Orange Street.
Walter Muir Whitehill, Boston: A Topographical History

For purposes of mutual defence and the establishment of social order, the Court held in London, Ma)1 21, 1629, contemplated that the settlements must be very compact, and that a certain plot or pale should be marked out, within which every one should build his house, and a half acre is named as the size of a house lot within the pale.
History of the town of Dorchester, Massachusetts. By a committee of the Dorchester antiquarian and historical society. Clapp Jr., E. 1859

The exact geographical limits of the Dorchester plantation were not determined till some time after its partial occupancy by the first settlers. Dr. Harris states that the Dorchester Company bought a tract from Roxbury Brook to Neponset, but he does not quote the authority for this assertion.
History of the town of Dorchester, Massachusetts. By a committee of the Dorchester antiquarian and historical society. Clapp Jr., E. 1859

Dorchester Neck, in its topographical appearance, was very uneven, abounding in hills and valleys.* Nook hill, in the north-west part of it, less than half a mile from the Heights, was a very important location for a battery, on account of its proximity to Boston. Gen. Howe perceived this, and undoubtedly intended to occupy it, and to dislodge the continental army, or at least to prevent their use of it. The place where this hill then was, is the spot on which now stands the Lawrence School-house. It was an eminence fifty feet or upwards above the sea. Washington made up his mind to fortify it, and on Saturday night, March 9th, sent a detachment for that purpose. It was one of those cold and blustering nights so common at that season of the year, and the soldiers were so imprudent as to build a fire for their comfort. This was seen by the British in Boston, who opened a severe fire upon them, principally from their battery near what is now the corner of Washington and Dover Streets.
History of the town of Dorchester, Massachusetts. By a committee of the Dorchester antiquarian and historical society. Clapp Jr., E. 1859

" One avenue to South Boston was by Sea Street, until recently known as Federal Street," said Mr. Burns. " Across the free bridge
and South Boston was reached. On the Boston side just where the gasometer recently stood, now covered by railroad tracks, was a little knoll on which were two or three houses and the windmill, from which it derived its name, Windmill Point.
HISTORY OF SOUTH BOSTON (ITS PAST AND PRESENT) AND PROSPECTS FOR THE FUTURE WITH SKETCHES OF PROMINENT MEN BY JOHN J. TOOMEY AND EDWARD P. B. RANKIN BOSTON, MASSACHUSETTS (1901).

"View of the South End of Boston in New England America & of the neck taken from the hill N.E. of the Common." Print. [ca. 1764–1799]. Digital Commonwealth, https://ark.digitalcommonwealth.org/ark:/50959/cn69ms54q

The original shoreline for Boston in colonial times is shown on Figure 4. Only a narrow causeway of land running about where Washington Street is now connected the several hills of Boston to the mainland. Most of the Back Bay, Lower Beacon Hill, Chinatown, and portions of the Fenway and the South End were a tidal estuary until landfilling began about the turn of the nineteenth century. The first major structure to be constructed in the Back Bay was the Mill Dam which was completed in about 1821. The dam carried a toll road and was built on what is now Beacon Street, extending from the Public Gardens to Brookline Street. The dam consisted of two parallel masonry block walls about 15 feet in height and 50 ft. apart, built on a grillage of timbers with the space between filled with mud and sand. The purpose of the dam was to use tidal water to power machinery in mills located along the cross dam on Gravelly Point. In 1831 two rail lines, the Boston & Providence and the Boston and Worcester were chartered and construction of their embankments across the tidal estuaries was begun almost immediately. The Boston & Worcester crossed the tidal flats at the location of the present Boston & Albany tracks, while the Boston & Providence Line crossed in northwest-southeast orientation, terminating at Park Square. The two lines intersected at what is now Back Bay Station. Quoting from Aldrich (1) "The railroads influenced the growth of Back Bay in two important ways. First they greatly interfered with the flow of water, hence reducing the usefulness of the area as a power project, increasing its undesirable aspects and hastening the day of its filling. Second, they influenced materially the ultimate layout of streets in the Back Bay, which factor had a tremendous impact on its physical and sociological development." Major filling of the tidelands began in the late 1850's. Fill for the decades long project came from Needham and consisted of clean sand and gravel. Filling was completed in the late 1800's and as sections were completed land was sold for residential and commercial development. In 1910 a tidal dam was built across the Charles River to control the height of the water in the river at about el +8, and in 1951 the Storrow Drive was built.

Final Report Report on Groundwater Observation Wells, for City of Boston - Inspectional Services Department/Groundwater Trust, by Stone & Webster Civil &Transportation Services, Inc (April 1990)

SOIL & GROUNDWATER FINDINGS BY AREA

MELNEA CASS BLVD / ISLAND ST / READING ST (AT HAMPSTON ST TO MASS AVE)

"According to the H&A Phase I, prior to the 1850s, the Site was undeveloped land on the north bank of Roxbury Creek. During the 1850s, the Albany Street area was filled behind a granite block seawall. By 1882, the Site was improved with two buildings (which overlapped onto adjacent properties) of the City of Boston Water Department. At that time, the Roxbury Canal conduit abutted the southeastern portion of the Site. Site usage by the Water Department included machine shops, water meter repair and testing, and carpenters shops. Materials likely used/generated by the Water Department included petroleum products, waste oil, metal cutting oil, lubricants and degreasing solvents. Heating of the Site buildings likely used coal, and steam heat from outside sources was used in the 1960s and 1970s. No evidence of underground or aboveground storage tanks was identified by H&A. In the late 1970s, the two building existing at that time were razed, and the Site was subsequently used for Boston City Hospital employee parking. No prior environmental evaluations were conducted on the Site. However, evaluations of an adjacent property identified volatile organic compounds (VOCs), TPH and polychlorinated biphenyls (PCBs) in subsurface soils and groundwater."

"H&A installed four test borings (for environmental and geotechnical purposes) on the Site on July 18 and 19, 1992. The borings, identified as E92-1 through E92-4, were installed within the footprint of the proposed building and rear courtyard, as shown on Figure 2. Soil samples were collected during drilling to determine Site stratigraphy and environmental quality. The Site soils consist of brown to black silty sand and gravel fill, including brick, ash, cinders and concrete, to a depth of 4.5 to 6.5 feet. Brown to dark gray organic silt and peat (some containing marine shell fragments) were present to depths of 11 to 26 feet. These deposits were underlain by soft to stiff olive to gray marine clay. Silver, cadmium, chromium, copper, mercury and lead were detected in the samples above their respective common ranges. A total of 2,544.7 tons of material were transported off-site for disposal at American Reclamation Corporation (Amrec) of Charlton, Massachusetts under Bill of Lading protocol in July and September 1994. During boring installations by H&A, groundwater was encountered at depths from 8 to 11 feet below grade, according to H&A boring logs. H&A installed 2-inch diameter PVC monitoring wells in the four borings, ranging in depth from 24 feet to 39 feet below grade."

"The Site was filled as part of overall expansion of the City of Boston. These fill soils typically contain coal ash and wood ash, and contain concentrations of metals and P AHs similar to those detected in the site soils. In addition, historically, coal was likely used for heating during early Site use. Ash and cinders were identified in soil samples collected from the Site, and are likely associated with the fill material or the use of coal. After initial development, the Site was used by the City of Boston Water Department to, among other supporting activities, test and repair water meters. Materials likely used/generated by the Water Department included petroleum products, waste oil, metal cutting oil, lubricants and degreasing solvents. Some of these materials may have been released to the Site soils during routine Site operations."

"H&A surveyed the tops of the wells and gauged water levels to determine groundwater flow direction. Groundwater levels appeared higher in the center of the Site and lower at the northwest and southeast ends. H&A determined that groundwater flow direction was outward from the center of the Site. H&A further indicated that the groundwater flow regime at the Site was similar to the flow regime on the adjacent parcel northeast of the Site."

"As indicated previously, Site fill soils included ash and cinders, and these were most likely part of the fill material used to fill the Site area. Many of the P AHs and metals detected at the Site fall within background concentrations determined by the DEP. Cadmium is the only compound whose EPC is above the background level. The cadmium EPC is largely driven by a single concentration an order of magnitude higher than other detections at the Site, and is from a sample of soil that was subsequently removed for the property."

RESPONSE ACTION OUTCOME STATEMENT MEDICAL EXAMINER'S BUILDING, 720 ALBANY STREET, BOSTON, MASSACHUSETTS, Prepared for Commonwealth of Massachusetts, RTN 3-4530 (June 22, 2010)

The Site was part of an intertidal salt marsh until being filled prior to 1897. The 1897 Sanborn Map depicts the Roxbury Channel immediately across Massachusetts Avenue as well does the 1900 USGS Topographic Map of Boston and Environs. The salt marsh was filled from multiple unknown sources. Historically, several lead manufacturing companies and gasoline stations have occupied the Site. According to information included in the July 2000 Phase I Environmental Site Assessment prepared by Haley & Aldrich, the Crosstown Center Property was occupied by a variety of lead manufacturers from the mid-to-late 1800s through the 1960s and several gasoline stations from the late 1930s up to 1979. A Site Plan showing the 1978 site features, including the location of
the former Mobil Station, is included as Figure 2-4. The National Lead Company of IIIII IIII Massachusetts, Boston Lead- Manufacturing Co. and Chadwick-Boston Lead Company all conducted operations at the Site. Thes&companies were primarily paint pigment manufacturers, , however, plumbing equipment suppliers and other industries have also occupied the Site.
investigation included both the DEC Building as well as the vacant EDIC owned Parcel 4 (in the vicinity of the former gas stations). As part of this subsurface investigation, both soil and groundwater samples were collected from twelve test pits (TP-1 through TP-12) and eight soil borings/monitoring wells (GZ-1 through GZ-8) installed in the northern and eastern portions of the Site. Analytical results from soil samples collected from the twelve test pits indicated that total lead was detected at concentrations ranging from 175 to 69,900 mg/kg. The 69,900 mg/kg concentration of lead was detected in soils collected from TP-6 at a depth of 5.2 feet below ground surface. TP-6 was located approximately 10 feet east of the DEC Building. Elevated levels of petroleum hydrocarbons were also detected in soils collected from the northern and eastern portions of the Site. Lead and other compounds were detected in shallow groundwater, IIIIhowever, concentrations detected were at levels below the applicable reportable concentrations. An application for a waiver of DEP oversight of further investigations and cleanup measures was submitted in April 1989 by EDIC and RTN 3-0245 was assigned by the MADEP on October 15, 1989. The disposal site is also identified as the Former National Lead Company. The limits of the disposal area defined in the Phase I report extend from the former DEC Building east towards Massachusetts Avenue. The locations of test pits and soil borings installed by GZA during the Phase I Investigation as well as the corresponding soil and groundwater analytical data are included in Appendix B-1

Phase II Site Assessment Report, Crosstown Center Development, 2001, RTN 03-0245

Phase II CSA Draft Crosstown Center Development (2001)

"Beneath the fill material, the test pits encountered natural deposits of marine sand and clay at Elevations ranging from approximately +6.6 to +11.3 feet. The natural deposit of marine sand was observed to consist of a compact mottled orange brown to yellow-brown silty fine sand. The marine clay was observed to consist of a firm to soft mottled yellow-gray silty clay. The natural deposits of marine sand and marine clay were not penetrated during the subsurface investigations. Based upon borings performed on nearby sites the marine clay extends to depths which exceed 100 feet below ground surface. Underlying the marine clay, a glacial till exists which generally consists of a gray, silty gravelly sand and is known to contain occasional cobbles and boulders.

Groundwater at the site was encountered within observation well OW-1 well at approximately 4.5 feet below ground surface which corresponds to about Elevation +11.8. During our subsurface investigation in June 2010, the surface of groundwater was observed in test pits TP-1 02, TP-104 and TP-105 at depths ranging from approximately 6 to 6.8 feet below the existing ground surface which corresponds to approximate Elevations +9.18 and +9.48, respectively. It is anticipated that the groundwater is seasonally perched on the surface of the relatively impermeable marine deposits. Future groundwater levels across the project site may vary from those reported herein based on such factors such as normal seasonal changes, runoff during or following periods of heavy precipitation, and alterations to existing drainage patterns.

CLASS A-3 RESPONSE ACTION OUTCOME STATEMENT RTN 3-29344, 20 REED STREET ROXBURY MASSACHUSETTS for Department of Environmental Protection, Bureau of Waste Site Cleanup, Project No. 5117 (June 21, 2011).

Borings showing “beds of marsh mud” from 20-86ft deep between Clapp & Magazine St.
Filled to 14ft high
Reports of quicksand
1885 Main Drainage Works.pdf

While laying main drainage excavating occurrence of quicksand esp along water fronts
1899 Report on Boston Main Drainage Works.pdf

Tributary to the Main Drainage System bounded by Charles River and Boston Harbor etc
Lowr portion, not more than 40ft above mean low water , 46 sq miles
Expected to be intercepted by a low level intercepting sewers so always need pumped
1899 Report on Boston Main Drainage Works.pdf

BRADSTON ST / MASS AVE CONNECTOR (AT MASS AVE TO EAST DEDHAM ST)

Fill Layers were encountered at the surface of all subsurface locations and varied in thickness from 3.0 to 15.0 ft. The fill layers were denoted under the following classifications:

Black/Grey/Red Brown/Brown Miscellaneous Fill consisting of a heterogeneous layer of gravel, sand, silt, clay, organics, peat, bricks, metal, rubber, wood, ash, I tires, bottles, wire, granite cobbles, boulders, leaves, roots, brick, concrete blocks, and cinders. It was noted that there was a petroleum odor to the sample collected in boring B-2 at a depth of 5.0-6.5 feet. The miscellaneous fill layer was very loose to very dense with a Standard Penetrations Test (SPT) N-Values varying between 1 and greater than 120 blows
Black Grey/Dark Grey Clavey Silt (ML) consisting of medium plasticity fines, with 0-5% fine gravel and coarse to fine sand, and 0-10% organics. The sandy silt layer was medium stiff with a SPT N-Values of 5 blows.
Red Brown Sand (SP-SM) consisting of varying percentages of coarse to fine sand, 10-15% coarse to fine subrounded gravel, and 0-10% nonplastic fines.
Grey Green Silty Clay (CL-CH) consisting of moderately plasticity fines, with an organic odor. The silty clay fill layer was soft with a SPT N-Value of 2 blows.

Organic Layers were encountered underlying the miscellaneous fill layer in test boring I B-1, B-2, B-4, B-5, test pit TP-2C, TP-3, interbedded between and below the clayey silt fill layer in test boring B-3, above and below the silty clay fill layer in test boring B-6,
and varied in thickness from 0.5 to 10.0 feet. The organic layers were classified under the following classifications:

Black/Grey Black Organic Silt (OL) consisting of slightly to highly plastic fines, 0-15% organics and peat fibers, 0-5% coarse to fine gravel, 0-30% fine sand, and 0-15% cinders, and pockets of fibers or shells. The organic silt layer was very I soft to medium stiff with a SPT N-Values varying between 0 (weight of hammer run) of 7 blows.
Black Peat (Pt) consisting of slightly plastic fines, was very loose with a SPT N-Values varying between 1 and 2 blows.

Black Brown Sand (SP) was encountered underlying the organic silt in test boring B-1 and was approximately 5.0 feet thick. The sand layer consisted of varying percentages of coarse to fine sand, 0-10% nonplastic fines, and 0-5% organics. The sand layer was dense with a SPT N-Value of 43 blows.

Blue Grey/Light Grey/Dark Brown Sandy Silt (ML) was encountered underlying the sand layer in boring B-1, underlying the miscellaneous fill layer in test boring B-7, and I was approximately 5.0 feet thick. The sandy silt layer consisted of nonplastic to slightly I plastic fines, with 15-25% coarse to fine sand and 0-10% coarse to fine subrounded gravel, 0-5% organics and fibers. The sandy silt layer was loose to very dense with a SPT N-Values varying between 8 to 62 blows.

Grey Brown Clayey Silt (ML) was encountered underlying the organic silt layer in boring B-2, underlying the peat layer in test boring B-4, and varied in thickness from 5 and 15.0 feet. The clayey silt layer consisted of medium plasticity fines, with 0-5% fine
sand. The sandy silt layer was very stiff to hard with SPT N-Values varying between 23 and 35 blows.

Grey/Blue Grey/Green Grey Silty Clay (CL. CH, and CL-CH) was encountered underlying the sandy silt fill layer in boring B-1 and B-7, underlying the clayey silt layer in test boring B-2, underlying the organic silt layer in test boring B-3, and varied in thickness between 67.0 and 105.0 feet. The silty clay layer consisted of low to highly plasticity fines, with 0-5% coarse to fine gravel, 0-30% fine sand, and occasional layers or seams of sandy silt or silt. The silty clay layer was very soft to hard with SPT N-Values varying between 0 (weight of hammer nnn) and 68 blows.

Brown Grey/Grey Glacial Till Layers were encountered underlying the silty clay layer in test boring B-l, B-2, B-3, B-5, B-6, B-7,and varied in thickness from 3 to 7 feet. was approximately 5 feet thick. The glacial till layers consisted of the following types of
materials:

Brown Grey Silty Clay (CL) consisting of low plasticity fines, with 0-10% coarse to fine gravel and coarse to fine sand. The silty clay layer was hard with a SPT N-Value of 45 blows.
Grey Brown Clayey Gravel (GC) consisting of varying percentages of coarse to fine gravel, 5-20% coarse to fine sand, 30-35% slightly plastic fines, with occasional cobbles and boulders. The clayey gravel layer was medium dense to very dense with a SPT N-Values varying between 39 and greater than 120 blows.
Grey Clavey Sand (SC) consisting of varying percentages of coarse to fine sand, 5-10% fine subangular gravel, 10-20% low plastic fines, and occasional cobbles and boulders. The clayey sand layer was very dense with a SPT N-Value greater than 120 blows.
Grey Sandy Silt (ML) consisting of nonplastic fines and 20-30% medium to fine sand. The sandy sit layer was very dense with a SPT N-Value greater than 120 blows.

Bedrock - Shale (Cambridge Argillite) was encountered underlying the silty clay till layer in test boring B-4. A split spoon sample of the shale layer was obtained form test boring location B-4 and noted as having the following properties: Light grey green, severely weathered and thinly bedded. Refusal blow counts were recorded in all boring locations.

The groundwater table was encountered approximately 6.0 to 10.4 ft below ground surface in all observation wells. For the purpose of this report, an assumed datum of 100 ft was located on the spindle of the hydrant on South Bay Avenue adjacent to the entrance to the United Trucking Company. Base on the groundwater reading recorded on May 9, 1988 from the observation wells, it was determined that the groundwater flows generally in a southerly direction, with an average hydraulic gradient of 0.0063 ft/ft. MB-8 generally flows in an easterly direction toward Boston Harbor.

20 Bradson, Roxbury MA, Mass. DEP Project Number 75029MA (June 1, 1988).

"Soils at the (Incinerator) site consist of 5 to 50 feet of miscellaneous fill overlying clay."
20 Bradson, Roxbury MA, Mass. DEP Project Number 75029MA (June 1, 1988).

"The Site is located on Bradston Street in Roxbury, Massachusetts and consists of a 0.38-acreparcel of land. The Site is bounded by Bradston Street to the north, parking lots to the east and west, and a commercial building to the south.. The building has been vacant for several years. Boston Consolidated Gas Company constructed the building in 1915 for use as an oil and paint house. It was renovated in 1921 and converted to use as shops. From the 1930's to the 1990's the building was utilized by various manufacturing operations including the manufacture of rubber products.

On Junel4 and 15, 2000 BGS advanced nine test pits at the Site (Figure 2). The test pits were advanced to a depth of approximately 7-feet. Groundwater was encountered at approximately 6-feet. Excavated material generally consisted of layers of sand and gravel fill materials of an urban nature containing wood, wood ash, brick, construction debris, coal and coal ash. Soil samples from the water table were collected at each test pit location. All excavated material was returned to the test pits.

On July 11, 2000 BGS advanced four soil borings/monitoring wells (MW-1, MW-2, MW-3 and MW-4) at the site. Composite soil samples were collected at each well location at a depth of 10 to 12 feet below ground surface (bgs) and submitted for laboratory analysis for EPH. This depth was chosen due to the presence of visual evidence of petroleum smearing due to a fluctuating water table. The soil sample at MW-3 was also analyzed for RCRA 8 metals and PAHs.

On August 9, 2000 three (3) additional soil borings/monitoring wells (MW-5, MW-6 and MW-7) were installed on site. Composite soil samples were collected at each well location at a depth of 4 to 8 feet below ground surface (bgs) and submitted for laboratory analysis for EPH with target compounds and RCRA 8 Metals. On August 16, 2000 groundwater samples were collected from all seven (7) on site monitoring wells to be submitted for laboratory analysis for Dissolved Lead, VPH and EPH.

The results of the subsurface investigation conducted at the Site as part of the RAM indicate the presence of elevated levels of Lead, Arsenic, EPH and several EPH target compounds, and PAHs. Lead above the Method 1 S-2/GW-2 risk based standard was detected in soil samples collected from TP-2 and MW-7. Arsenic above the Method 1 S-2/GW-2 risk based standard was detected in soil samples collected from MW-S and MW-7. EPH above the Method 1 S-2/GW-2 risk based standard was detected in soil samples collected from TP-2, TP-6, TP-7 and MW-5. PAHs above the Method 1 S-2/GW-2 risk based standard was detected in soil sample collected from MW-3.

Groundwater elevation measurements recorded during the July 2000 and August 2000 sampling rounds
indicate that groundwater flow at the Site is generally toward the east-northeast (Figure 3 and Figure 4).

RESPONSE ACTION OUTCOME STATEMENT, 33 Bradston Street Roxbury, MA 02118, RTN 3-19481, Boston GeoScience Corporation for Bradston Associates, L.L.C. 633 Tremont Street, Boston, MA 02118 (September 28, 2001)

"The Crosstown Center Site is located along Massachusetts Avenue between Albany Street and Melnea Cass Boulevard in Boston (Roxbury), Suffolk County, Massachusetts. The RTN 3-0245 site has an industrial history that dates back to the mid to late 1800s. Former lead manufacturing operations, former gasoline service stations operations, and extensive fill materials, as well as smaller industrial operations (junk storage, auto body repair, welding, etc.) are the known and/or suspected sources of contamination.

RELEASE ABATEMENT MEASURE PLAN CROSSTOWN CENTER REDEVELOPMENT PROJECT, 801 MASSACHUSETTS AVENUE BOSTON, MA, RTN # 3-245 (January 2013)

According to Sanborn maps of the area, the Site was City of Boston property, occupied by the Water Department and a coal shed/boiler plant in the late 1800s and early 1900s. According to aerial photographs of the area, the coal shed/boiler plant was demolished in the 1970s and the current-day BMC Power Plant and parking lot located at 750 Albany Street was constructed in the 1970s. The historical boiler plant that existed on the Site during the late 1800s and early 1900s was a coal fired power plant until the 1920’s. From the 1920’s to the 1970’s, the boiler plant used fuel oil to generate power. Fuel oil tanks are shown on the Sanborn Fire Insurance Maps and are not located within the limits of the Site. The types and quantity of the fuel oil are not depicted.
The 1887 Sanborn Map indicates that the Site was occupied by the Ham and Carter Drain Pipe Factory. An office and wagon house were located within the approximate limits of the Site, along with another unidentifiable building. Prior to construction Ham and Carter Drain Pipe Factory, the Site was tidal flood lands that was owned by the City of Boston and used as a fairground

The general subsurface stratigraphy identified at the test borings at the Site and 771 Albany Street is outlined in the table below, listed in order of occurrence below ground surface (bgs):

 Fill that consists of medium dense to very dense SAND with varying amounts of silt, gravel, brick, ash, and cinders was encountered at each boring location. The thickness of the Fill ranged from 10.5 ft to 12.5 ft.
 Organic Soils described as soft ORGANIC SOIL with gravel, sand peat fibers and trace shell fragments was encountered beneath the fill at the test boring locations. The organic deposits in HA13-1 were 22 ft thick, HA13-D1 was terminated at 20 ft and did not extend through the entire organic layer.
 Marine (Clay) Deposits described as a lean CLAY was encountered at HA13-1 beneath the organic soils. The clay was described as stiff within the upper portion becoming softer with depth; this clay is described locally as the Boston Blue Clay. Based on limited data from other test borings which penetrated the clay, the thickness of clay ranged between 43.0 ft and 70.0 ft. Location HA13-1 was terminated in the Marine Clay at 61.0 ft.

"The approximately 3.5-acre site is located at the intersection of Massachusetts Avenue and Albany Street in a mixed commercial and industrial area of Roxbury. The EDIC Parcel 4 site and adjacent DEC property were occupied by lead product manufacturing facilities and other industries including a lumber company and brewery. A Mobil station occupied the northeast portion of the EDIC Parcel 4 property for approximately 50 years until the 1970's.

The EDIC site is located in the eastern part of the Boston Basin which is a fault-bounded structural depression located within the Milford-Dedham tectonic zone of eastern Massachusetts. The coastal low land is bounded by the waters of Boston Harbor and Boston Bay to the east; the Fells Upland to the north; the Sharon Upland to the south; and, merges with the Needham Upland to the west. The basin is structurally defined by the Northern Border thrust fault and a step-like series of thrust faults to the south. The rocks within the basin are both folded and faulted. Much of the bedrock within the Boston Basin is deeply buried by quaternary glacial deposits. Bedrock was not encountered in test pits or borings excavated at the EDIC Parcel 4 site or adjacent property during the Phase I or II studies.

Regional geology in the Boston Basin was topographically refined by continental glaciation during the Pleistocene. With the exception of coastal areas and valleys lying less than 50 feet above sea level, most of the rocks of the basin are overlain by glacial drift. Based on subsurface explorations conducted during the Phase I and II studies, the site consists of approximately 5 to 15 feet of fill overlying sand and silt or dense silt deposits. The fill generally consists of medium sand and gravel intermixed with construction debris (bricks, concrete, asphalt). Clay was also observed underlying the fill in several locations in the northern and eastern portions of the site. Permeable sand and sand and gravel deposits were observed during the Phase I study at borings excavated in the southwestern portion of the site.

Regionally, groundwater flow direction is northeasterly towards the Fort Point Channel, located approximately one-mile northeast of the site, and continues northeasterly into the Boston Inner Harbor which ultimately discharges approximately two miles east/southeast into Boston Harbor. Localized groundwater flow direction, based on water elevation surveys conducted at the site during the Phase I and II studies, appears to be northeasterly across the site towards Massachusetts Avenue. Depth to groundwater at the site, based on water level measurements during the Phase I and II studies, generally varied from approximately 5 to 10.5 feet below ground surface.

Economic Development and Industrial Corporation of Boston Report on EDIC Crosstown Industrial Park, Parcel 4 PHASE II - COMPREHENSIVE SITE ASSESSMENT October, 1991

The history of this property was researched back to the turn of the century, when atlases of this period indicate the property was owned by the New York, New Haven, and Hartford Railroads. Portions of this area (parts of 1027-6, 1027-3, 1027-2, and 1027) were under water, and the location of docks along the edge of South Bay Avenue. A 1915 atlas referenced businesses located along these docks, probably leasing warehouse space from the railroad. Some of these included Curtis Pope Lumber Company, Starret Fields Company, and, in the vicinity of Lots 1029-2, the Burnham Coal Company. Burnham Coal Company had their coal pockets located here (Topeka Rd was once named Burnham Rd). The remainder of the property was used as a railyard. By 1931, the area had been completely filled, and was a portion of 4,157,766 square feet (sq ft) I of railyard belonging to New York, New Haven, and Hartford Railroad. I The railroad owned this property into the 1950's. Businesses on South Bay Avenue in the 1950's prior to the construction of the incinerator, included the Downs Lumber Company, at 54 South Bay Avenue and Hatheway and Patterson Company, (an electrical equipment and supply company) at 100 South Bay Avenue. The incinerator site is 3.36 acres in size. The City of Boston took two parcels from the railroad in 1955 by eminent domain, and a third was acquired from the Commonwealth of I Massachusetts, Department of Public Works (DPW) in 1968. From 1959 to 1975, the city operated an incinerator on this property. It was designed by Metcalf and Eddy, and built from 1957 to 1959. It had a capacity of 800-900 tons of refuse per day, and was closed by court order in August of 1975. In 1960, businesses on South Bay Avenue had dried up, 54 and 100 South Bay Avenue were
vacant. 120 South Bay was still a storage warehouse. From 1963 on, the only listed business ion South Bay Avenue (according to city directories for this period), was the City of Boston, DPW incinerator, at 70 South Bay Avenue.

3.2 Surface Conditions. The subject property is approximately 300,000 sq ft in plan area and is covered by three existing building, several office trailers, asphalt pavement, soils, miscellaneous debris, several trucks and 18-wheel trailers, abandon railroad tracks, vegetation and shrubs. The existing buildings varying in size from 1,470 to 6,262 sq ft and are used by United Truck Leasing, T. G. O'Connor, and Safe 'N' Sound. Approximately 80,000 sq ft of asphalt pavement is located on the southern end of the site, around these buildings. A portion of the asphalt area is used by the City of Boston Traffic Commission for the storage of damaged vehicles. This parking lot was noted to be heavily stained by oil and anti-freeze, which had leaked for the damaged vehicles. The majority of the northern end of the site is covered with piles of miscellaneous debris. This consisted of asphalt, leaves, wood chips, metal, concrete, road salt, dirt, light poles, and cold patch. Excavation operations executed in this area encountered glass, paper, ash/cinders, wire, i granite cobbles, tires, bricks, and concrete blocks. There is one underground storage tank located on the subject parcel. That tank is situated on the southwestern section of the property, near Bradston Street, and is operated and used by United
Truck Leasing. The size of the storage tank was not known since fire department records did not record it's presence. The tank is situated approximately 75 ft west of the United Truck Building (See Figure 3). Our visual inspection noted no other tanks on the subject parcel, although there two large above ground tanks located on the adjacent parcel near the South Bay Incinerator unit. An investigation of the excavation found no other indication of contaminated soils. The remainder of the surficial examination of the site, found no visual signs of staining or I contamination from past or present site usage. Visual inspections of the property were conducted on several occasions. Vegetation on the site was in good condition, showing no signs of stress or contamination. Selected soil sample collected during the drilling operations had a petroleum odor and discoloration.

3.3 Abutters, The site is bordered by the following:

1. Southeast Expressway and Entrance Ramp is located on the northwestern, northern, northeastern, and eastern sides of the site. There are no signs of contamination on the roadways. Vegetation immediately adjacent to the site is in excellent condition, showing no signs of contamination.
2. South Bay Incinerator is located on the southeastern side of the site. The building is currently vacant, operations having been ceased in August, 1975. At the present time the area is used by the Department of Public Works (DPW) for the storage of road salt and miscellaneous debris (light poles, sand, cold patch, empty drums, trailer, bookmobile, concrete, styrofoam, car gasoline tanks, car parts, wood, metal, furniture, tiles, tires, several 275 gallon tanks, pavement, tar paper, & shingles). There are numerous stained areas and two large above ground storage tanks on the site. The property is 123,432 sq ft in size.
3. South Bay Avenue is located on the southwestern side of the northern half of the subject parcel and divides the site in half. There are no signs of contamination on South Bay Avenue. Vegetation immediately adjacent to the site is in excellent condition, showing no signs of contamination
5. Commercial/Office Buildings are located on the southwestern side of the subject property. The land is used for the following business activities. 1. City of Boston - Traffic Commission & Bridge Service 2. Safe 'N' Store - a self storage facility 3. Three vacant buildings - one was used by Master Chemical, the second used by Penta, and the third by Steiff Rubber. The vegetation in from of these buildings and adjacent to the site was covered with miscellaneous debris. The debris consisted of paper, wood, metal, several trailer dump bodies, cardboard, and fabric.

3.4 Subsurface Conditions
Our knowledge of the subsurface conditions at the site is based on the results of our field investigation. The following subsurface strata were encountered starting from the ground surface:

a. Asphalt Pavement was encountered at the surface of test borings B-4 through B-6 and varied in thickness from 1 to 3 inches.
b. Fill Layers were encountered at the surface of all subsurface locations and varied in thickness from 3.0 to 15.0 ft. The fill layers were denoted under the following classifications:
- Black/Grey/Red Brown/Brown Miscellaneous Fill consisting of a heterogeneous layer of gravel, sand, silt, clay, organics, peat, bricks, metal, rubber, wood, ash, I tires, bottles, wire, granite cobbles, boulders, leaves, roots, brick, concrete blocks, and cinders. It was noted that there was a petroleum odor to the sample collected in boring B-2 at a depth of 5.0-6.5 feet. The miscellaneous fill layer was very loose to very dense with a Standaid Penetrations Test (SPT) N-Values* varying between 1 and greater than 120 blows. (SPT N-Value is the number of blows for a 140 lb. hammer falling freely through 30 inches required to advance the standard 1-3/8 inch inside diameter by 2 inch outside diameter split-spoon sampler the last 12 inches of an 18 inch sampling interval.)
- Black Grey/Dark Grey Clavey Silt (ML) consisting of medium plasticity fines, with 0-5% fine gravel and coarse to fine sand, and 0-10% organics. The sandy silt layer was medium stiff with a SPT N-Values of 5 blows.
- Red Brown Sand (SP-SM) consisting of varying percentages of coarse to fine sand, 10-15% coarse to fine subrounded gravel, and 0-10% nonplastic fines.
- Grey Green Silty Clay (CL-CH) consisting of moderately plasticity fines, with an organic odor. The silty clay fill layer was soft with a SPT N-Value of 2 blows.
- Organic Layers were encountered underlying the miscellaneous fill layer in test boring B-1, B-2, B-4, B-5, test pit TP-2C, TP-3, interbedded between and below the clayey silt fill layer in test boring B-3, above and below the ;ilty clay fill layer in test boring B-6, and varied in thickness from 0.5 to 10.0 feet. The organic layers were classified under the following classifications:
  - Black/Grey Black Oreanic Silt (OL) consisting of slightly to highly plastic fines, 0-15% organics and peat fibers, 0-5% coarse to fine gravel, 0-30% fine sand, and 0-15% cinders, and pockets of fibers or shells. The organic silt layer was very I soft to medium stiff with a SPT N-Values varying between 0 (weight of hammer run) of 7 blows.
  - Black Peat (Pt) consisting of slightly plastic fines, was very loose with a SPT N-Values varying between 1 and 2 blows.
d. Black Brown Sand (SP) was encountered underlying the organic silt in test boring B-1 and was approximately 5.0 feet thick. The sand layer consisted of varying percentages of coarse to fine sand, 0-10% nonplastic fines, and 0-5% organics. The sand layer was dense with a SPT N-Value of 43 blows.
e. Blue Grey/Light Grey/Dark Brown Sandy Silt (ML) was encountered underlying the sand layer in boring B-1, underlying the miscellaneous fill layer in test boring B-7, and I was approximately 5.0 feet thick. The sandy silt layer consisted of nonplastic to slightly I plastic fines, with 15-25% coarse to fine sand and 0-10% coarse to fine subrounded gravel, 0-5% organics and fibers. The sandy silt layer was loose to very dense with a SPT N-Values varying between 8 to 62 blows
f. Grey Brown Clavey Silt (ML) was encountered underlying the organic silt layer in boring B-2, underlying the peat layer in test boring B-4, and varied in thickness from 5 and 15.0 feet. The clayey silt layer consisted of medium plasticity fines, with 0-5% fine sand. The sandy silt layer was very stiff to hard with SPT N-Values varying between 23 and 35 blows.
g. Grey/Blue Grey/Green Grey Silty Clay (CL. CH, and CL-CH) was encountered underlying the sandy silt fill layer in boring B-1 and B-7, underlying the clayey silt layer I in test boring B-2, underlying the organic silt layer in test boring B-3, and varied in thickness between 67.0 and 105.0 feet. The silty clay layer consisted of low to highly plasticity fines, with 0-5% coarse to fine gravel, 0-30% fine sand, and occasional layers or seams of sandy silt or silt. The silty clay layer was very soft to hard with SPT
N-Values varying between 0 (weight of hammer nnn) and 68 blows.
h. Brown Grey/Grey Glacial Till Layers were encountered underlying the silty clay layer in test boring B-l, B-2, B-3, B-5, B-6, B-7,and varied in thickness from 3 to 7 feet. was approximately 5 feet thick. The glacial till layers consisted of the following types of materials:
- Brown Grey Silty Clay (CL) consisting of low plasticity fines, with 0-10% coarse to fine gravel and coarse to fine sand. The silty clay layer was hard with a SPT N-Value of 45 blows.
- Grey Brown Clavey Gravel (GC) consisting of varying percentages of coarse to fine gravel, 5-20% coarse to fine sand, 30-35% slightly plastic fines, with occasional cobbles and boulders. The clayey gravel layer was medium dense to very dense with a SPT N-Values varying between 39 and greater than 120 blows.
- Grey Clavey Sand (SC) consisting of varying percentages of coarse to fine sand, 5-10% fine subangular gravel, 10-20% low plastic fines, and occasional cobbles and boulders. The clayey sand layer was very dense with a SPT N-Value greater than 120 blows.
- Grey Sandy Silt (ML) consisting of nonplastic fines and 20-30% medium to fine sand. The sandy sit layer was very dense with a SPT N-Value greater than 120 blows.
i. Bedrock - Shale (Cambridge Argillite) was encountered underlying the silty clay till layer in test boring B-4. A split spoon sample of the shale layer was obtained form test boring location B-4 and noted as having the following properties: Light grey green, severely weathered and thinly bedded. Refusal blow counts were recorded in all boring locations.

Groundwater
The groundwater table was encountered approximately 6.0 to 10.4 ft below ground surface in all observation wells. For the purpose of this report, an assumed datum of 100 ft was located on the spindle of the hydrant on South Bay Avenue adjacent to the entrance to the United Trucking Company. Elevations of the observation wells were recorded, based on the assumed datum. The elevation of the groundwater in each observation wells was recorded on May 9, 1988: (depth 6.08 to 10.42 ft) (table elevation 88.93-91.64 ft).
Groundwater levels may be affected by local anomalous conditions and may be dependent on seasonal factors and thus may not represent the levels to be encountered in the future. Generally, groundwater readings are highest in the early spring and lowest in the fall.

3.6 Site Hydrologic Conditions
I Base on the groundwater reading recorded on May 9, 1988 from the observation wells, it was determined that the groundwater flows generally in a southerly direction, with an average hydraulic gradient of 0.0063 ft/ft.

5.1 Department of Environmental Oualitv Engineering (DEOE). 5.1.1 General Site Hydrologic Information. The site is located in the Massachusetts Bay Drainage Basin, Subbasin Number 8 (MB-8). The soils in this drainage basin have not been surveyed or classified by the USGS. This area has not been surveyed because in the opinion of the USGS the underlying soil are unsuitable for well development. Further information supplied by the USGS shows that the groundwater in subbasin MB-8 generally flows in an easterly direction toward Boston Harbor.

M.G.L. 21E Site Assessment and Analytical Testing Report, Suffolk County House of Correction, South Bay Avenue, Lots 1027-2, 1027-3, 1027-6, 1029-2, 1028, & 1027-8; Roxbury, Massachusetts

Test Pits I * TP-1 to TP-8 identify (TP) test pits number 1 to 8 which were excavated in an area used in the past to stockpile road salt and dump miscellaneous fill and debris. Test Pits I * TP-1 to TP-8 identify (TP) test pits number 1 to 8 which were excavated in an area used in the past to stockpile road salt and dump miscellaneous fill and debris

M.G.L. 21E Site Assessment and Analytical Testing Report, Suffolk County House of Correction, South Bay Avenue, Lots 1027-2, 1027-3, 1027-6, 1029-2, 1028, & 1027-8; Roxbury, Massachusetts

5.1.3 Petroleum and Hazardous Material Information
I Records collected from the DEQE show five confirmed and three potential hazardous waste sites (See Figure 4) within a one mile radius of the site. The following sites were recorded by the DEQE on the Water Supply Protection Atlas - Hazardous Waste Overlay and in the April 15, 1988 edition of the "List of Confirmed Disposal Sites and Locations to be Investigated":

Boston City Limits
1) Landfill (DEQE File # 33B-035-001F) is located between the Expressway and South Bay Avenue which is situated adjacent to or part of the subject property, on 1 the southeastern side. This landfill is considered a potential hazardous waste site. The landfill is located in the Massachusetts Bay Sub-basin Number 8 (MB-8) and classified as status unknown. The site is also the location of the closed South Bay Incinerator and the property used by the DPW as a storage area for roadsalt.  A DEQE memorandum (See Appendix J), dated June 10, 1986 regarding the South Bay Incinerator, stated that the incinerator handled 700 tons of trash per day in 1978. Soils at the site consist of 5 to 50 feet of miscellaneous fill overlying clay. According to the memorandum, the only incident recorded at the South Bay Incinerator consisted of a dumpster fire on October 3, 1982. The fire was the result of the illegal disposal of 40 drums of 1-N-Methylaminoanthraquinone. The fire was controlled by the fire department and the spill cleaned up by Jetline, Inc. This material originated from Benzenoid Organics Inc. in North Bellingham; a company which went out of business. The memorandum cited several possible contamination I sources which consisted of the following: Filling of the site with possible contaminated material; Contamination resulting from railroad operation on the property (railyard); Liquids or materials stored at the site while the incinerator was in operation or after the incinerator was closed.  The memorandum concludes that the priority for an inspection of the site is low based upon the lack of sensitive receptors and the lack of a documented release at the site. However, since some type of release of hazardous materials may have occurred at the site, a site inspection should be conducted as priority permits.

2) Former Master Chemical (DEQE Case # 3-060) is located at 27-29 Bradston Street which is situated 200 feet southeast of the site. A Phase 3 and 4 investigation of the site has been performed to study remedial action alternatives, and design and implement a remediation alternative to eliminate the contamination from a hazardous material release on the property. Master Chtrmical was the location of a chemical Manufacturing operations for the products used in the shoe industry, primarily cleaners, as well as manufacturing of shoe finishes, dressings, slips, and leather softeners. The site is located in Massachusetts Bay Subbasin Number 8 (MB-8).  The problem was first discovered during an investigation of the property by BSC Engineering, Inc in March, 1985 (Appendix K). BSC installed 3 observation wells and tested selected soil and groundwater samples. The analyses encountered several volatile organic compounds (VOC's) and numerous Base/Neutral Extractables  semivolatile organic compounds. Material used in the site operations were stored in 4 underground storage tanks, which consisted of one 2,000 gallon tank of toluene, one 1,000 gallon tank of acetone, and two 1,000 gallon tanks of naptha. In 1982 it was discovered that water was entering the toluene tanks. At that time the tank was I pumped dry and left in ground. These tanks were removed in November, 1984 by Pollution Control Unlimited and the location were backfilled in association with the closing of the chemical operations at the site.
A further study of the site was conducted by Camp, Dresser, and McKee, Inc. (CDM) and the information provide in a repoced dated December 3, 1985 (Appendix L). The investigation included the installation of one observation well and the Iexcavation of eight test pits, testing of selected soil and groundwater samples, determining groundwater information, and testing excavated soil with an HNu and OVA meters for volatile emissions. The report noted high concentrations of VOC around the removed tanks, and a layer of floating oil on the groundwater. The report concluded that toluene contamination of the soil and groundwater were site related, but the that the oil contamination was from an off-site source. The report did not recommend any remediation actions for the oil contamination, since it was believed that the source was located off-site. It did recommend the removal of the toluene contaminated soil and recovery of any toluene observed on the groundwater table by pumping (skimming the water table).
In a report from Goldberg-Zoino & Associates, Inc. (GZA) to the DEQE, dated January 1987 (Appendix M), the DEQE required the removal of soil with head space concentrations greater than 50 ppm and the recovery of floating toluene from the groundwater. On July 30, 1986, under GZA supervision, contaminated soil was excavated and removed from the site. The r-moval operations were performed by McDonald and Watson Waste Oil Company. Approximately 550 gallons of toluene I(and water mix) was pumped from the grou dwater table and 200 cubic yards of contaminated soil removed from the site. S ils with concentration under 50 ppm were stockpiled separately from the contamin ed material for backfilling operations.
During the excavation operations a concrete holding tank was encountered between ithe two buildings. This tank, installed in 1965, was used as a temporary holding tank for latex waste and pumped out regularly (approximately weekly). McDonald and Watson removed approximately 600 gallons of liquid and 1,200 gallons of sludge from this tank. An analyses of the contents of the tank found several chlorinated solvents and aromatic hydrocarbons with methylene chloride and toluene present in high concentrations (Total VOC = 140,000 ppb). Two additional  observation wells were installed by GZA on the site and groundwater was tested once each month for four months. The results of the testing recorded decreasing concentrations of VOC's during that time period. The GZA report concluded that no further remediation actions were required at the site at that time.
Additional communication occurred between the DEQE and GZA on September 16, 1987 (Appendix N). DEQE suggested groundwater treatment should be performed at the site. GZA indicated that the results of their testing program showed decreasing Iconcentrations of VOC's at the site and the remediation alternative proposed by the DEQE would be in-appropriate at this site, because of the presence of the oil on the groundwater (not site related) and other contamination located at other sites in the surrounding area. They also indicated that the source of the contamination was removed from the property and that the contaminated material surrounding the tank was removed. No further information was available on the status of this site with the DEQE.

3) Automobile Junkyard (DEQE File # None) is located between the Expressway and Moore Street which is situated approximately 700 feet southeast of the subject property. This automobile junk is considered a potential hazardous waste site and located in the Massachusetts Bay Sub-basin Number 8 (MB-8).

4) DEQE File # 33A-035-008A is located at the intersection of Gerald Street and Island I Street. This location is listed as a confirmed hazardous waste site under investigation by the DEQE. The site is located approximately 1100 ft southwest of the site in Massachusetts Bay Subbasin Number 8 (MB-8).

5) Middlesex Trucking and Coach (DEQE File # 33A-035-004A and DEQE Case # 3-256) is located on Gerald Street which is situated 1100 feet southwest of the site.  A Phase 2 investigation is currently in progress to evaluate an existing contamination problem (petroleum release) located on the property. The site is located in Massachusetts Bay Subbasin Number 8 (MB-8).

6) Lyons Property (DEQE Case # None) is located at 76-80 Kemble Street which is situated 2000 feet southwest of the site. A Phase 2 investigation is currently in progress to evaluate an existing contaminati )n problem (hazardous waste release) I located on the property. The site is located in Massachusetts Bay Subbasin Number 8 (MB-8).

7) A Salt Storage Area (DEQE File # 31B-035-003B) is located under the expressway near Randolph Street. A salt storage area is considered a potential hazardous waste site. The reason being that the storage procedures could result in the migration of the salt into the groundwater aquifer and contaminate a major drinking water source S(public and private well development). The salt storage pile is located approximately 2500 ft northeast of the site in the Massachusetts Bay Drainage subbasin Numbers 8 (MB-8) and classified as a confirmed salt storage pile.

8) North Shore Recycles (DEQE Case Number 3-247) is located on B Street between West First Street and Cypher Street, which is situated 5200 feet east of the site. A Phase 1 investigation is currently in progress to evaluate an existing contamination problem (hazardous waste release) located on the property. The site is located in Massachusetts Bay Subbasin Number 8 (MB-8).

5.1.4 Hazardous Waste Generators 3 The following Hazardous Waste Generators and or Handlers (See Figure 3) were recorded with the Environmental Protection Agency (EPA) and located near the subject parcel. 1) Master Chemical (EPA File Number MAD-001005768) is located approximately 200 feet southeast of the site at 27-29 Bradston Street. This location is listed with the EPA as a generator of hazardous materials. This facility is no longer is business at this location, having closed down it's operations in November 1984.

5.1.5 Violations
According to information from the available files (Spills and Sites Database) at the DEQE in Woburn, there have been no complaints registered against the site regarding hazardous waste contamination. However, there have been complaints regarding petroleum and hazardous materials problems in the surrounding area. Those sites are recorded as follows:

On April 20, 1983 the DEQE was informed of a spill of a white milky liquid at the Master Chemical Facility located at 27-29 Bradston Street. No further information was available on the size of the spill or the clean-up operations.
On June 1, 1984 there was a spill of 600 gallons of No. 6 Fuel oil by the Boston DPW on South Bay Avenue. The spill was cleaned by Pollution Control Unlimited and no further action was required by the DEQE.
On December 3, 1984 a leaking tank was removed by Pollution Control Unlimited at the Master Chemical Facility located at 27-29 Bradston Street. The tank had been I used for the storage of Naptha Solvents. The site is currently under a more detailed investigation to delineate the contamination problem located on the property.
On August 1, 1985 an unknown quantity of kerosene was spilled by the Paul Connor Construction Company at the intersection of South Hampton Street and Cumming Street. No further information was available on the size of the spill or the clean-up operations.
On February 2, 1986 there was a spill of 100 gallons of diesel fuel at 100 South Hampton Street by United Truck Leasing. The spill was cleaned by Jetline and no further action was required by the DEQE.
On May 16, 1986 there was a spill of 8 pints of Methyl Methacryl at 120 South Hampton Street by Health Company Inc. The spill was cleaned by Clean Harbors and no further action was required by the DEQ2.

5.2 Boston Board of Health
Mr. John Shea, Principal Health Inspector, City of Boston, reports no problems at the subject parcel concerning spills, leaking tanks, or anything else which would create an environmental concern to the site. However, he stated that there have been several spills from fuel tanks by the DPW on the incinerator property, the incineration unit is full of asbestos, used for a storage area for salt, and that there has been significant illegal dumping on that property.

5.3 Boston Fire Prevention Department
According to information collected at the City of Boston Fire Department, Special Hazardous Waste Division, there have been no problems (petroleum or hazardous material) recorded for the subject parcel or for the surrounding area. No recorded of above or below ground tanks were listed on the subject parcel with the Fire i Department, although there is an outstanding permit issued for 70 South Bay Avenue (the DPW). There was no information as to what type of storage container or product.

M.G.L. 21E Site Assessment and Analytical Testing Report, Suffolk County House of Correction, South Bay Avenue, Lots 1027-2, 1027-3, 1027-6, 1029-2, 1028, & 1027-8; Roxbury, Massachusetts

"The proposal is to construct a concrete culvert for drainage from Massachusetts Avenue to Dorchester Avenue and to fill entirely the
Roxbury Canal, South Bay, the portion of Dorchester Brook from the end of the existing culvert on railroad property northerly to
South Bay, and that portion of Fort Point Channel down to Dorchester Avenue."

Provisions to collect and dispose of the storm runoff which is tributary to South Bay and the Channel will require construction of a concrete box conduit as shown on Plates No. 2 and 3. The design of the conduit section is based on hydraulic properties which allow for future construction and filling of Fort Point Channel all the way to Northern Avenue. The existing storm and sanitary overflow drains which now discharge into any part of the water-way above Dorchester Avenue will be tied into the main conduit. Until recently, it had been assumed that long point-bearing piles would be required for support of the culvert. However, a section of the culvert already constructed for the Boston Central Artery was built on gravel backfill after excavation of organic silt. Furthermore, studies for the Dover Street embankment indicated long piles were not required for that section of the culvert even though the height of fill will be greater. It is believed, therefore, that long bearing piles driven through the blue clay stratum to refusal are not required for support of any portion of the proposed culvert.

Considerable savings in construction cost will result if the culvert can be constructed in the open without a cofferdam. However, this
ay be possible only where adequate room is available for construction of stable dikes and where the culvert invert is highest. Preliminary details of the conduit design as shown on Plate No. 2 call for three major types of foundation treatment: 1. The upper reach of the conduit will be constructed on a gravel embankment placed after excavation of organic silt, utilizing earth dikes to facilitate dewatering so construction may proceed in the dry. 2. The next section down to the existing expressway culvert will be supported on timber friction piles driven through the organic silt into the clay stratum again utilizing earth dikes. 3. The lower portion of the conduit will be founded on gravel backfill placed after organic silt is excavated down to the blue clay, all construction to take place within a double wall steel sheet pile cofferdam which will remain in place as an integral part of the culvert.

It is probable that the foundation treatment for the culvert will vary considerably over its length due largely to its size and to the proximity of Boston blue clay. A careful survey of soil conditions throughout the area prior to construction may very well indicate the possibility of more extensive use of treatment 1 or 2 and less use of treatment 3 as outlined above resulting in less costly construction. Settlement of the culvert following its construction will be less than the estimated compression of the clay stratum under 20 ft. of fill. A maximum of 3 to 4 inches is expected while differential settlement will be relatively small. Anticipated settlement of the culvert may be compensated for, if necessary, by a slight increase in size or by adjustments in the as-built invert elevation.

To retain the fill and prevent tide water from flowing upstream, a sea wall must be constructed across Fort Point Channel along the easterly side of the Dorchester Avenue Bridge as shown on Plate No. 3. The design as shown calls for adequately braced steel sheet piling to be driven as close as practical to the existing bridge with provisions in the piling for the discharge of the drainage conduit. The scheme offered is tentative only and many variations are feasible and should be investigated based upon more complete subsurface exploration.

Placing of Fill Material. A geologic section showing approximate subsoil conditions underlying the Fort Point Channel area is shown in Plate No. 3. Information from recent John F. Fitzgerald Expressway borings was used to prepare the section between Massachusetts Avenue and Broadway Bridge. In addition, use was made of boring data published by the Boston Society of Civil Engineers and logs of borings for the proposed Dover Street embankment crossing Fort Point Channel. Bottom of the channel corresponding to top of organic silt was obtained from recent soundings taken as part of this investigation. During the past two years, considerable organic silt and other miscellaneous fill from construction of the Expressway have been deposited in the channel, especially from Massachusetts Avenue to Dover Street. As a result, the character of the channel has been altered appreciably. At the present time, the mud line varies from El. 0 to El. -20 at the proposed location of the culvert while the depth of organic silt and fill is between 5 and 30 feet. Underlying the organic silt is a deep stratum of clay varying from stiff yellow clay toward the top surface to soft blue clay at greater depth. Thickness of the clay stratum varies between 40 and 100 ft. Below the clay are thin layers of pervious sands and glacial till (hardpan) over a blue slaty shale.

The 1950 report by the Port of Boston Authority proposed that fill for the channel be obtained by hydraulic means from the Old Harbor area. Since the size of the area to be filled has been greatly reduced, fill to be placed to Dorchester Avenue only, and since considerable filling has occurred since 1950, it is believed that continued filling by conventional methods is indicated. It is estimated that 700,000 cu. yds. of fill are required to bring the Channel to approximately Elevation 10. Proposed construction activity in the Greater Boston area is likely to produce the majority of earth fill required for the Channel. Major projects proposed include the Prudential Center, garage under the Boston Common, the Federal Center near Scollay Square and a second Sumner Tunnel to East Boston. If contracts for these projects specify disposal of earth excavation in the Fort Point Channel area, the cost of filling the Channel is greatly reduced. Furthermore, it is probable that such a convenient disposal area would reduce the construction cost of the specified project itself. Construction of the culvert will require considerable quantities of fill for construction of earth dikes and working platforms for heavy equipment. Thus, the total quantity required from other sources is less than the estimated 700,000 cu. yds.

Few limitations need to be placed on the type of earth fill used in the Channel once the culvert is constructed. Foundations for all but the lightest temporary structures which may be constructed in the future will need to be founded on piles where earth fill overlies organic silt. It is considered important to exclude rock, boulders, granite blocks, brick walls, concrete and other hard materials from fill in order to minimize future pile driving and excavation problems. It will be desirable to place a minimum of 2to 3 ft. of granular soil over the filled area, especially where organic soils are dumped, to provide a sanitary, stable, free draining surface."

1959 Senate Bill 0498. Report of the Special Commission Relative to Filling and Improving South Bay and Part of Fort Point Channel in the City Of Boston: A Comprehensive Report for the Filling and Improving a Portion of Fort Point Channel and South Bay. (1959).

Report of the Special Commission Relative to Filling and Improving South Bay and Part of Fort Point Channel in the City of Boston, Senate — No. 498 (1959).

A Study for the Development of Fort Point Channel, South Bay, and Adjacent Areas, Port of Boston Authority (1950).

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BIOSQUARE DRIVE / FRONTAGE RD (AT EAST CONCORD ST TO UNION PARK ST)

NEIDL

"Based on observations made during subsurface investigation activities conducted to date, subsurface conditions at the site include urban fill material with significant quantities of subsurface wood and lumber that were likely the remnants of the former wharfs or piers or other buildings. Large, subsurface void spaces characteristic of urban fill are also present. Starting from the bedrock and extending upward the soil generally consists of a variable thickness of glacial till, stiff to medium gray clay, varying in thickness from 40 feet to over 100 feet, a relatively thin and discontinuous deposit of sand, overlain by peat and organic silt, which in turn is overlain by the granular fill... Groundwater is present on the site at depths 5 to 11 feet below ground surface. Based on local topography, the groundwater at the site is expected to flow generally northeasterly toward the Fort Point Channel which is nearly 1 mile away from the site."

NIH, Final Environmental Impact Statement National Emerging Infectious Diseases Laboratories, BioSquare Research Park in Boston, Massachusetts (Dec. 2005).

601 ALBANY ST, 2001 SOIL TESTS:

LEAD 1,870 mg/kg 11/21/01; 1,900 mg/kg 12/31/01; 436 mg/kg 12/31/01
MERCURY 3 mg/kg 11/21/01; 16 mg/kg 01/03/02; 5.98 mg/kg 01/03/02
CHROMIUM 19.6 mg/kg 11/21/01; 20.5 mg/kg 12/31/01
BARIUM 435 mg/kg 12/31/01; 199 mg/kg 12/31/01
SILVER 9.27 mg/kg 12/31/01

601 ALBANY ST, 2002 SOIL TESTS:

FSL-10 (2002): 1'-3' black fill with asphalt, coal, and slag pieces; 3'-8' gray ash, black fill with ash, coal, asphalt, brick and debris; 7'-8' black organics; 8'-12' blue-green clay; 12'-14' tan clay; 14'-16' blue-green clay.
FSL-11 (2002): 1'-6' gray ash and gray fill with metal debris; 6'-7' gray ash; 7'-8' black fill with wood debris; 8'-12' void/no recovery; 12'-16' gray clay.
FSL-12 (2002): 1'-5' blackfill with brick and asphalt; 5'-16' Gray Clay

Release Abatement Measure, 120 Day Status Report, 601 - 603 Albany Street Roxbury, MA 02116 (March 2002)

"The approximately 32,500 sq. ft. subject site property is located at 650 Albany Street (Parcel C), in downtown Boston. Historically, the Colonial shoreline passed longitudinally (west to east) approximately parallel to Albany Street and the Biosquare II site. The Roxbury Canal was constructed westward from South Bay, south of the site, in the mid 1800's. Following construction of the Roxbury Canal conduit, the canal was filled during the 1960's and early 1970's. The Albany Street area of Boston was filled during the mid-1850's and was occupied by one and two-story brick buildings shortly thereafter.

According to Sanborn Fire Insurance Maps and other historic maps for the site the buildings within the central portion of the Biosquare II site were used as military barracks by the U.S. government until 1868. From approximately 1882-1977, the site was occupied by eight buildings (Buildings 21,22,23,25,26,31,34 and 35) utilized by the City of Boston Water and Sewer Services, the Boston Public Works Department Street Cleaning and Sanitary Services and Highway Division Paving Services.

Buildings 21, 22 and 23 were used mainly for storage and as wagon sheds until they were razed in approximately 1949. Building 23 was briefly occupied by a blacksmith and carpenter shop until it was razed in approximately 1928. Building 25 located at 650 Albany Street, occupied only a portion of the current subject site, with a majority of the building extending onto the adjacent parcels to the south and west. Building 25 utilized a 1,500-gallon underground #2 fuel oil tank which was located along the inside of the southeastern wall of the building. This tank was located immediately to the south of the current subject site. This building was utilized for vehicle storage and repair, carpentry, and forging. Building 26 was erected on the eastern portion of the site in approximately 1874 and was used for storage and office space by the City of Boston Paving Division until it was razed in approximately 1949. Building 34 was constructed on-site in approximately 1939 and Building 31 existed by 1950. Usage of these buildings is unknown. Building 35 was erected at 630 Albany Street in approximately 1949 by the Public Works Department-Street Paving Division. The building occupied a portion of the current subject site (Parcel C) and a portion of the adjacent parcel to the east of the current subject site (Parcel F). The building was used as office space until approximately 1977, when the building and surrounding property was transferred to the Boston Traffic Police Department. The Boston Traffic Police Department operated a tow truck radio dispatch office from this building and operated the Boston Traffic Police Department Tow Lot Number 5, on the eastern half of the site from approximately 1977 to the present. A 275-gallon aboveground storage tank was located along the eastern edge of the building, immediately to the east of the current subject site. By the mid-1970's, all of the buildings were razed and the Biosquare II site was utilized as a parking lot.

Environmental test pits and test borings completed during the 1998 Haley & Aldrich subsurface exploration programs for the subject site indicate the site is underlain by approximately 5 to 20 feet of miscellaneous fill. The fill composition typically consists of intermixed sand, silt, gravel, cinders, bricks, building rubble, cobblestones and ash. The fill is underlain by a layer of organic soils approximately II to 23 feet in thickness. Organic soils are underlain by a 75 to 99 foot layer of marine deposits consisting of gray silty clay with sand and gravel. Underlying this is a thin layer of Glaciomarine soils and Glacial Till. Bedrock was encountered at depths ranging from 106 to 134 ft. below existing ground surface.

Groundwater levels most recently observed in observation wells on-site indicate groundwater levels at depths ranging from 5 to 11.5 ft. below the ground surface. The inferred direction of groundwater flow is to the north/northwest towards Albany Street and ultimately towards the Fort Point Channel. Groundwater levels at the site do not appear to be influenced by tidal action within the Roxbury Canal Conduit.

TIER 1 CLASSIFICATON SUBMITTAL BIOSQUARE II DEVELOPMENT, 650 ALBANY STREET - PARCEL C, BOSTON, MASSACHUSETTS, RTN 3-16655, Haley & Aldrich, Inc. for Massachusetts Department of Environmental Protection, File No. 10666-130 (March 1999).

A National Pollution Discharge Elimination System (NPDES) Permit Exclusion (#98-123) was granted by the EPA on 28 May 1998. The Permit Exclusion authorized discharge of up to 100 gallons per minute of construction dewatering effluent to the municipal storm drain system leading to the Fort Point Channel and Boston Harbor. Discharge to date has typically been intermittent, and has been due to standing water accumulated within the excavation after rain events. The dewatering system was designed in accordance with the permit requirements, installed and operated by J. Derenzo Co. (Earthwork sub-contractor). Monitoring and sampling of the influent and effluent has been conducted by Haley and Aldrich, Inc., and analyzed by a DEP-approved laboratory. Results of discharge water quality analyses indicate levels of contaminants have not been detected above laboratory limits for the discharge water samples.

TIER 1 CLASSIFICATON SUBMITTAL BIOSQUARE II DEVELOPMENT, 650 ALBANY STREET - PARCEL C, BOSTON, MASSACHUSETTS, RTN 3-16655, Haley & Aldrich, Inc. for Massachusetts Department of Environmental Protection, File No. 10666-130 (March 1999).

Groundwater infiltration or discharge of surface water runoff into the Roxbury Canal Conduit provides the primary, currently existing pathway for potential off-site migration of contamination. The Roxbury Canal Conduit discharges into the Fort Point Channel, which is connected to Boston Inner Harbor. The tidal influenced water level in the Roxbury Canal Conduit is anticipated ,to generally range from EI. 10 to EI. 0 (BCB), corresponding to mean high and low water, respectively. Groundwater infiltration into or water exfiltration out of the conduit is possible.

On-site construction dewatering was conducted in accordance with a National Pollution Discharge Elimination System (NPDES) Permit Exclusion (#98-123) granted by the EPA on 28 May1998. Discharge during the period 21 April 1998 to18 August 1998 was intermittent and was due to standing water accumulated within the excavation after rain events. Influent and effluent testing was below the limits specified in the Permit and the applicable Reportable Concentrations (RCGW-2) and there was not a significant difference between the test results of the influent and effluent samples. This resulted in the decision to remove the water treatment portion of the system.

RELEASE ABATEMENT MEASURE (RAM) COMPLETION REPORT IV, BIOSQUARE II, 650 ALBANY STREET, BOSTON, MASSACHUSETTS, RTN 3-16655, Haley & Aldrich, Inc. Boston, Massachusetts, File No. 10666-130, (April 2000).

Prior to the placement of fill, the area including the site was located under the waters of South Bay. The development of the Central Artery transportation corridor in the 1950's brought about the filling of South Bay and the culverting of the Dorchester and Roxbury Canals. The closest surface water is the Fort Point Channel, which is located approximately one-quarter mile to the north. However, the Roxbury Canal culvert and Dorchester Canal culvert, as illustrated on the Site Plan, run in a northerly direction underneath the parcel. These two subsurface drainage channels discharge to surface water, and have been considered surface water bodies in this assessment. The surrounding site receptors are shown on Figure 3, Geographical information Services (GlS) Map. Shallow subsurface soils encountered during soil borings on the property were characterized as mostly urban fill. The urban fill consisted of layers of sand and gravel as well as coal, cinders, brick, ash, glass and other debris.
Phase II - Comprehensive Site Assessment: Release Tracking Number 3-14507, City of Boston, Vehicle Fueling Facility 400 Frontage Road, Boston, Massachusetts (April 5, 2002

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1.3.2 Location and Layout
Prior to the placement of fill, the area including the site was located under the waters of South Bay. The development of the Central Artery transportation corridor in the 1950's brought about the filling of South Bay and the culverting of the Dorchester and Roxbury Canals.
The approximate coordinates for the location of the Property are Latitude 42° 20' 25"
north and Longitude 71° 03' 46" west. UTM Zone 19 coordinates are 330045.3 meters east and 4689377.6 meters north. The site is located at an approximate elevation between 15 to 17 feet above sea level. The site is relatively flat with a gentle slope to the southeast. Surface runoff drains into at least two storm water catch basins located on the property.
Abutting properties are the Boston Transportation Department Tow lot to the south, a Massachusetts Bay Transportation Authority (MBTA) repair facility across the railroad tracks to the east, Frontage Road to the west, and the Boston Public Works Central Maintenance Facility and offices to the north.
The area is industrially zoned. Up to 10 people are expected to be on the property at a given time either in one of the buildings or on the paved refueling area. No residences appear to exist within 500 feet of the release area. No institutions, (any publicly or privately owned hospital, health care facility, orphanage, nursing home, convalescent home, educational facility, or correctional facility, where such facility in whole or in part provides overnight housing) are located within 500 feet of the Site. The Pine Street Inn, a shelter for homeless persons, is located just over 500 feet from the site at 343 Albany Street
Schools in close proximity to the Property include the Cathedral and Cardinal Cushing High Schools and the Condery School. All three schools are located approximately 1,800 feet away, the Cathedral High School to the west and the Cardinal Cushing High School and Condery School to the east. The Boston
University Medical Center is approximately 1,400 feet to the south.
The MCP soil classifications were determined to be S-3/GW-2 and S-3/GW-3. The rationale for assigning these categories is discussed in Section 7.
The closest surface water is the Fort Point Channel, which is located approximately one-quarter mile to the north. However, the Roxbury Canal culvert and Dorchester Canal culvert, as illustrated on the Site Plan, run in a northerly direction underneath the parcel. These two subsurface drainage channels discharge to surface water, and have been considered surface water bodies in this assessment. The surrounding site receptors are shown on Figure 3, Geographical lnformation Services (GlS) Map.

Earth Tech assessed the subsurface soil conditions on the eastern and western portions of the PWD fueling facility property during Phase 11 activities. The ground surface at the facility is primarily covered by asphalt, concrete and buildings.  Shallow subsurface soils encountered during soil borings on the property were characterized as mostly urban fill. The urban fill consisted of layers of sand and gravel as well as coal, cinders, brick, ash, glass and other debris. At depths greater than eight feet BGS, Earth Tech encountered silt and clay deposits that are likely to be native marine sediments. Bedrock was not encountered during the subsurface site investigation. Based on the Bedrock Geologic Map of Massachusetts (Zen, 1983 ), the Site is located in the Boston Basin in the Milford-Dedham zone. The bedrock material contains  approximately two kilometers of Proterozoic sediments, composed of two  formations: the Cambridge Argillite (argillite, quartzite, sandstone, and conglomerate) and the Roxbury Conglomerate (conglomerate, sandstone, siltstone, argiUite, and melaphyre). Beneath the Proterozoic bedrock is the Mattapan Volcanic complex (rhyolite, melaphyre, agglomerate, and tuft) which is approximately one kilometer in thickness. The lowermost bedrock is composed of granite

Surface Water
As discussed in Section 1.2.2 the closest surface water is the Fort Point Channel located approximately one-quarter mile to the north. The Roxbury Canal culvert and Dorchester Canal culvert are located between the former and existing fueling facilities, and lie in approximate north-south orientations. The culverts converge immediately to the north of the property and ultimately discharge into the Fort Point Channel.
During the Phase II and Supplemental Phase II Investigations, Earth Tech reviewed drainage plans obtained from Boston Water and Sewer Commission, and dated
March 2, 2000. Each culvert is depicted as two seventeen-foot wide parallel
channels. According to the plans, the culverts are constructed of concrete several feet thick. No information was available on the culvert floor, expansion joints or other perforations. The plans did not indicate interconnections between property catch basins and the culverts. The plans also indicated that there are no manholes or other surface access to the culverts within 200-feet of the property. During a visual inspection, Earth Tech did not encounter any surface accesses to the culverts on the fueling facility property. These features suggest that the water in the culverts would not be impacted by contaminated groundwater located on the property. During the Phase II investigation, groundwater contamination at concentrations above GW-2 and GW-3 were not found to extend to the culverts. Due to limited access to the culverts, Earth Tech was not able to collect water samples from the culverts.

Some of the underground utilities at the site also appear to be potential migration pathways. The electrical lines and water lines on the site do not appear to be pathways since they are all located outside of the contaminated areas of the site as determined by the assessment. xxx max- truth check the following. If a problem, please call. If not, deliver report. xxxxx
The approximate depth of the drainage invert at CB #I is 5.7 feet BGS while the total depth of the basin is approximately 8.5 feet BGS. Based on the historic depths to water in the nearest monitoring wells (MW-I and RSTA), discharge of groundwater to the drain lines appears unlikely. Further, although the invert of the catch basin may be below the water table, based on the depth to water, any flow would likely be from the catch basin to groundwater, not in the opposite direction. In addition, CB # 1 is approximately 50 feet from the groundwater contaminant source area and is not directly downgradient from the source. Therefore, the release is not anticipated to have a significant impact to the catchbasin drainage system. CB #1 was inspected and screened for VOCs on March 28, 2002, using a PID. There was no evidence of an impact of petroleum to the catchbasin: VOCs were not detecting in the air in the catchbasin and no sheen was observed on the standing water (5.72 feet BGS) in the catchbasin. The Roxbury Canal culvert and Dorchester Canal culvert are located between the former and existing fueling facilities, and lie in approximate north-south orientations. The culverts converge immediately to the north of the property and ultimately discharge into the Fort Point Channel. Earth Tech reviewed drainage plans obtained from Boston Water and Sewer Commission (dated March 2, 2000).
According to these plans, each culvert is constructed as two seventeen-foot wide parallel concrete channelsrete several feet thick. No information was available on the culvert floor, expansion joints or other perforations. However, concrete culverts typically have a floor to prevent flowing water from eroding the supporting soil. In addition, there are usually limited joints or other openings, reducing the opportunity for groundwater to discharge into the culvert and groundwater contours indicate flow parallel to the culverts, not toward them., and contaminant concentrations m groundwater typically decrease with distance from the source areas.
The plans did not indicate interconnections between property catch basins culverts.  (Interconnections between property catch basins and the culverts would increase the opportunity for contaminants to enter them) The plans also indicated that there are no manholes or other surface access to the culverts within 200-feet of the property.  During a visual inspection, Earth Tech did not encounter any surface accesses to the culverts on the fueling facility property.  These features suggest that the water in the culverts, and therefore surface water (the Fort Point Channel) would not be impacted by contaminated groundwater located on the property. Therefore, these underground utilities do not appear to be significant migration pathways. In addition to the forgoing, the large capacity of the culverts relative to the potential volumes that could be discharged would likely dilute the contaminants to levels that are below the method detection limits in the culverts. A large additional dilution would occur upon discharge to the Fort Point Channel.

BORING RST-7 9/16/1998 15-17ft Light gray silt and clay, little fine sand, moderate H2S odor. Bottom at 17ft.

Phase II - Comprehensive Site Assessment Release Tracking Number 3-14507,  City of Boston Vehicle Fueling Facility,  400 Frontage Road Boston, Massachusetts (April 5, 2002)

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The subject site occupies an approximate 118,000 square-foot plan area that fronts onto East Newton Street to the west and is located within the street block that is bound by Albany Street to the south, East Brookline Street to the east, and Harrison Avenue to the north. Within the street block, the subject site is bordered by existing medical buildings to the north, and the newly constructed Henry M. Goldman School of Dental Medicine building located in the southwest corner of the street block. The existing and proposed conditions are indicated on Figure 2. The subject site contains an existing currently unoccupied building that occupies an approximate 60,000 square-foot plan area. The existing building is generally bordered by a sallyport and paved drive aisle to the north, landscaped areas and a paved private roadway to the east, an outdoor pavilion/courtyard to the west, and landscaped and paved parking areas to the south. The subject site is currently an active construction site. The existing building has been recently vacated by the Boston Medical Center

".... No areas designated as solid waste sites (landfills) are noted as being located within 3,000 feet of the MCP site.... There are no water bodies at the subject site. The closest body of water is the Bass River that leads to the Fort Point Channel located approximately 3,200 feet to the northeast of the subject site"

Underlying the surface treatments (asphalt, concrete, or landscaping) is a granular fill material that covers the entire area of the release site. The historically placed fill material extends to depths ranging from approximately 8.5 feet to 20 feet below the existing ground surface. The urban fill material was observed to consist of brown to light brown, sand and gravel, with some to trace silt, also containing brick, wood, ash and cinders.
Within select explorations on the subject site, an approximately 6.5- to 9.5-foot-thick organic deposit was encountered that generally consisted of dark brown, organic silt, with occasional traces of clay, sand, and peat fibers. The organic deposit was observed to be discontinuous at the subject site.
The fill material or the organic deposit is underlain by a marine sand deposit consisting of light to dark gray, fine to medium sand, with trace amounts of silt. Within select locations, the fill material or organic deposit was underlain by marine clay consisting of light gray or brown, clay, with trace amounts of silt. The borings were terminated within the organic deposit, marine sand, or marine clay deposit at depths of 6 to 20 feet below the ground surface.

Based on a groundwater level survey, groundwater generally flows in a northwesterly direction. The analysis of groundwater has not detected concentrations of the COCs in excess of the RCGW-2 standards. Further, the depth at which the release has been detected in fill material is located above the surface of groundwater which ranges from approximately 10.7 and 11.3 feet below ground surface. Based upon the analysis of groundwater and shallow depth of contaminated fill material, groundwater is not considered to have been affected by a release of the COCs. The current MassDEP database, searched on July 12, 2022, indicates that adjacent parcels are not active MassDEP-listed release sites, therefore, it is unlikely that the release is attributable to a specific source from adjacent properties. From at least 1887 through 1914, a former building situated at the southeastern portion of the site was occupied by various industrial tenants, including carpenter shop, felt works, a furniture manufacturing facility, a piano manufacturing company, and an electric company. The presence of the COCs can be attributable to historical industrial activities pertaining to the use and storage of OHM within this former building. Alternatively, given that the release area does not extend below the layer of fill material, the presence of the COCs can also be attributable to the heterogeneous nature of the discontinuous layer of urban fill material that was historically deposited as backfill to level the site for development in the late 1800’s. Further, a PLM coal ash analysis, performed on a soil sample obtained from GP-312 between 0 and 2.5 feet below g

PHASE I INITIAL SITE INVESTIGATION REPORT AND TIER CLASSIFICATION; PHASE II CONCEPTUAL SCOPE OF WORK F/K/A NEWTON PAVILION RTN 3-36976 BOSTON, MASSACHUSETTS AUGUST 2, 2022, McPHAIL ASSOCIATES, LLC
Prepared For: Massachusetts DEP Northeast Regional Office On Behalf Of: Division of Capital Asset Management and Maintenance obo Commonwealth of Massachusetts obo Massachusetts Department of Public Health, Tenant

595 Albany st - parcel 1175, 2.7k sqft, 10 ft asl, gw may flow NE "however direction of regional gw flow in the vicinity of the site may vary due to the influence of local topography, underground utilities (e.g. storm drains, utility ducts, water mains, etc.) and heterogeneous subsurface conditions.
brick cellar has direct floors
alley associated with EI Dupont and M&L autobody
previously used by Mac Battery Factory, atuo battery facility
595 Albany St, South Boston, MA, Project No 20129, March 1992

575 Albany dupont no 3-0245, e deadham st,4k gallon underground storage tank (UST) with heatin fuel in alley off east deadham st
unearthed March 1989 and removed shortly after
PHC analysis 6ppm-110ppm (leaking pipe or spill during transfer)
DEQA gave ok to "pave the area where the tank was removed from with the understanding that further work may be requested on the site in the future'
in 1992 fire dept said no record of any USTs within 1/2 mile; no env/heath dept files
Preliminary Environmental Site Assessment Update for the Property Located at 595 Albany St, South Boston, MA, Project No. 20129, (March 6 1992).

The Site is located in a commercial and residential area in the South End section of Boston. Fort Point Channel is located approximately one mile northeast of the Site; the Charles River is located approximately 1 ¼ miles north of the Site. The Disposal Site is located on the northeasterly side of East Concord Street, just southeast of its intersection with Washington Street. The Disposal Site (RTNs 3-19472 and 3- 28957) consists of two contiguous parcels of land addressed as 8 and 10 East Concord
Street, a portion of an unpaved parking lot adjacent to 10 East Concord Street, and a portion of the public roadway (East Concord Street) located just southwest of 8 and 10 East Concord Street. A single-family townhouse is located on each of the parcels
addressed as 8 and 10 East Concord Street; the two townhouse buildings share a common wall. The building located at 8 East Concord Street also shares a common wall with 6 East Concord Street to the northwest; a multi-unit residential building adjoins the unpaved parking lot to the southeast. The City of Boston South Burial Ground adjoins the Site to the northeast, and East Concord Street adjoins the Site to the southwest, beyond which is the Home for Good (an elderly homeless shelter and associated office space) and residences. The general area surrounding the Site consists of residential, commercial and retail properties. A Locus Plan is attached as Figure 1.
The Site is located in a commercial and residential area in the South End section of Boston. Fort Point Channel is located approximately one mile northeast of the Site; the Charles River is located approximately 1 ¼ miles north of the Site....The soils at the Site consisted of granular fill material over natural clay. CHES removed the contaminated fill from within the building footprints, and extended the excavation approximately 2 to 3 feet down into the clay; apparently the fissures created by former root structures provided a pathway for contamination to migrate into the top portion of the clay. Therefore, the lower limit of contamination was not reached. The excavation of contaminated clay material was terminated in May 2000 when it became clear that it would
be financially infeasible for OBRI to remove all contaminated material from the Site.
8-10 East Concord, RAO (2010).

MBTA RAIL YARD / WIDETT CIRCLE (AT E DEDHAM ST TO EAST BERKLEY ST)

"Cabot Yard is located immediately south of the intersection of Dorchester Avenue and West Fourth Street The Site includes the eastern half of Cabot Yard encompassing the bus garage and parking areas/access roads located north and south of the garage. The Site also includes abutting portions of properties located at 220, 248, and 250 Dorchester Avenue, all of which are located less than 100 feet east of Cabot Yard. In addition, the Site includes the Pump Station, which is located approximately 150 feet southeast of Cabot Yard along the southern side of the Haul Road and adjacent to West 6"' Street and Dorchester Avenue. The Site is located in an area zoned for mixed use (residential, commercial, and industrial). Cabot Yard is an approximately 28-acre parcel of land occupied by two large multi-story buildings used for offices and repair/maintenance of buses and trains. These buildings occupy approximately 50% of Cabot Yard and the remainder consists of paved parking and access roads or railroad lines. Cabot Yard is bordered to the north by West Fourth Street and commercial businesses, to the east by Dorchester Avenue and commercial businesses, to the south by the Haul Road and a CSX Corporation railroad line, and to the west by the Boston Department of Public Works. The Pump Station is owned and operated by MassPike and pumps collected stormwater for a portion of the Haul Road to the Fort Point Channel located approximately 1/3-mile to the northwest. The Pump Station is an approximately 0.15-acre parcel of land occupied by 1 one-story brick and mortar pump station building. Approximately 75% of the Pump Station is occupied by the building and the remainder consists of concrete walkways and an unpaved hill leading towards the CSX railroad line and the Haul Road. The Pump Station is bordered to the northeast by West Fifth Street and commercial businesses, to the southeast by commercial businesses, West 6"' Street and residences, to the southwest by the Dorchester Avenue overpass, and to the northwest by the CSX railroad line and the Haul Road."

"Cabot Yard (previously known as the South Bay Maintenance Facility) was purchased in 1969 by the Commonwealth of Massachusetts from the Penn Central Transportation Company (Stone & Webster, 1993). The current buildings at Cabot Yard were completed in 1973. Presently Cabot Yard is owned and operated by MBTA. Cabot Yard has been used as a railway facility for over 125 years. In 1875, according to insurance maps of Boston prepared by the Sanborn Company, the Old colony Railway operated a car house, engine house, machine shop, boiler shop, car repair shop, car paint shop, and coal shed on the western half of Cabot Yard. Tenements, a stone yard, and a marble works occupied the eastern half of the property. The Bromely & Co. Atlas of the City of Boston shows that by 1899 rail lines extended to fill the eastern half of the property. The Bromely Atlas of 1919 shows Cabot Yard owned by the Old Colony Railroad Company."

"In general the topography at Cabot Yard slopes gently toward the northeast; however, the northwest corner of Cabot Yard slopes downhill toward the west. Also, Dorchester Avenue slopes downhill to the north and, at Cabot Yard's northern property boundary, it is several feet below Cabot Yard ground surface elevation. The elevation of the South Boston Haul Road near Cabot Yard is approximately 10 to 20 feet below the surrounding topographic elevation and slopes downhill to the northeast. The elevation of the Pump Station, located south of the South Boston Haul Road and northeast of Dorchester Avenue, is approximately 10 feet above the Haul Road and 5 to 10 feet below the topographic elevations to the southwest and southeast. Because Cabot Yard and the surrounding area is predominantly paved, surface water runoff is collected in catch basins and routed to Boston Water & Sewer Commission's sewer in Dorchester Avenue. Surface water runoff on the South Boston Haul Road is collected in a series of catch basins and underdrains and routed to the Pump Station, where the collected water is pumped via two force mains towards the northeast to the Fort Point Channel."

"Groundwater at the Site is categorized as GW-2 and GW-3. GW-2 classification is applicable because contaminated groundwater is located within 30 feet of occupied buildings and the average annual depth to groundwater is approximately 15 feet below grade. Site groundwater is also categorized as GW-3 because groundwater in the area is assumed to eventually discharge to the nearby Fort Point Channel and Boston Harbor. The criteria listed for GW-1 classification specified in 310 CMR 40.0932 (4) are not met at this Site. As shown on the Area Receptors Map in Figure 3 and discussed in Section 1.6, the Site is not in an area designated as a Current or Potential Drinking Water Source Area."

"Seven (7) geologic units were encountered during Weston & Sampson's April 2000 and April 2001 Supplemental Phase II investigation. These units include, in stratigraphic succession from youngest (shallowest) to oldest (deepest):

Sand (Fill): Brown to black fine to coarse sand, trace gravel and brick.
Silt: Gray to dark gray silt with little to trace sand.
Clayey Silt: Yellowish tan to gray clayey silt with trace fine sand.
Sand & Gavel: Dark gray to black coarse sand and fine gravel.
Clay: Gray clay with lenses of silt and fine sand.
Lower Sand: Gray to brown fine to medium sand, trace silt and fine gravel.
Sand and Silt: Tan to gray fine and medium sand and silt.

The sand (fill) unit was encountered in all drilling locations and at depths up to 15 feet below grade. The average thickness of the sand (fill) unit was approximately 8 feet from north to south and approximately 10 feet west to east across the Site. The sand (fill) unit was thickest primarily in areas north and south of the Cabot Yard bus garage. Non-native materials observed in the sand (fill) unit included: asphalt, ash, glass, coal, brick and wood. Petroleum odors and staining were observed in borings WS-1 through WS-4, WS-10, WSA-1 through WSA-3, SW-2, and SW-4. The observed petroleum odors and staining ranged in depth intervals of 3-5 feet inWS-10 and 24-26 feet inWS-1.

Clayey silt was noted in the southern portion of the Site in borings WSPS-1, WSPS-2, and SW-1, and in the eastern portion of the Site in boring WSA-4. The encountered clayey silt unit ranged between 3 to 12 feet below grade. Lenses of fine sand and clay were observed in the clayey silt unit. No petroleum odors or staining or non-native materials (e.g., ash, brick, glass, etc.) were noted in soil samples collected from the clayey silt unit. The clay unit was found in the central portion of Cabot Yard, WS-2 and WS-3, and in the eastern area of the Site, WSA-I through WSA3.

The clay unit ranged in thickness of 2 feet in boring WS-3 to 5 feet in boring WS-2. Petroleum odors and staining were observed in WS-2 and WS-3, but no odors or staining were observed in this unit at WSA-1 through WSA-3. No fill material was noted in the soil samples collected from the clay unit. The lower sand unit is generally present in the lower portions of all soil borings except WS-7 and was encountered between 8 feet (WSA-4) and 27 feet (SW-4) below grade. Soil boring WS-7 is located on the northern portion of Cabot Yard. No non-native materials such as brick, glass wood or ash were present in the lower sand unit. Petroleum odors and staining were present in WS-1, WS-3, SW-2, and SW-4.

The sand and silt layer was observed in borings WS-11, SW-1, and SW-4. Tan to gray interlayered fine sand and silt were present in SW-1 at a depth of 15 feet to 21 feet. Tan sand and silt were observed in WS-11 and SW-4 at depths of 19 and 20 feet, respectively. No fill material was observed in the sand and silt layer. No petroleum odors or staining were observed in this unit. A confining layer was not encountered at the Site during the Supplemental Phase II investigation or any other previous investigation. In addition, the depth to bedrock was not determined and no bedrock outcrops were observed at or near the Site. According to the USGS Bedrock Geologic Map of Massachusetts (Zen et al., 1983), the Site is located within the sedimentary rock portion of the Milford-Dedham Tectonic Zone of eastern Massachusetts. The bedrock type underlying the Site is likely a sedimentary (sandstone or conglomerate) rock of the Cambridge Argillite Zone."

"On May 9, 2001, Weston & Sampson collected groundwater depth measurements from all accessible monitoring wells at the Site (Table 6). The depth to groundwater at the Site ranged from 4.29 feet below grade at SW-6 to 22.28 feet at WS-1. Groundwater elevations ranged between 77.00 feet at WS-1 and 89.07 feet at SW-6. Based on the corrected groundwater contours shown in Figure 6, groundwater at the Site flows in two distinct patterns: 1) most groundwater at and east of Cabot Yard flows toward a slight depression located under the Cabot Yard bus garage and 2) groundwater in the southern portion of Cabot Yard flows southeast via a steep gradient toward the South Boston Haul Road and the Pump Station. The hydraulic gradient across the Site was calculated using groundwater elevations collected on May 9, 2001. Horizontal hydraulic gradients were calculated based on groundwater elevations at monitoring wells SW-3 to WSA-1, RIZ-5 to WS-10 and groundwater elevations south of RIZ-4 and north of the Haul Road. The average horizontal hydraulic gradient (IAvG) across the Site was calculated to be 0.060 fl/f. A downward vertical gradient of 0.22 fl/ft was calculated using groundwater and saturated screen elevation data from wells WS-10 and WS-1.

On May 2,2001, Weston & Sampson conducted four (4) slug tests at monitoring wells WS-4, WSA-1, SW-1, and SW-10. Due to the varying locations and screen depth intervals of these wells, each slug test was performed in a separate geologic unit (Figure 5). The WS-4 screen is located in the sand and gravel unit, WSA- 1 is located in the clay (with trace sand) unit, SW- 1 is located in the sand and silt unit, and SW-10 is located in the sand unit. Using the data collected from these slug tests, hydraulic conductivities (K) were calculated for each monitoring well/geologic unit. Hydraulic conductivities at the four wells ranged from 2.36 feet/day to 2.91 feet/day."

"The field screening results and general observations are presented in EST's report in Appendix D. According to their sampling report, EST observed petroleum odors in WS-4 and WSA-2 groundwater wells during sampling. The pH measurements ranged from 4.97 (WSA-5) to 7.22 (WS-4). Specific conductance measurements ranged from 335 micromhos per centimeter (pmhos/cm) in RIZ-6 to 21,899 ptmhos/cm in WS-4. Dissolved oxygen concentrations ranged from 0.11 milligrams per liter (mg/1) in WS-4 to 6.76 mg/I in WSA-4."

"Cabot Yard, Metals/Inorgancis: Dissolved cadmium was not detected in the 3 samples collected. Total iron and manganese were detected at 210,000 pg/1 and 240,000 kg/1 in wells WS- I and WS- 3, respectively. Total manganese was detected at 14,000 jig/1 and 5,200 jlg/1 in wells WS-1 and WS-3, respectively. Dissolved iron was detected at 86,000 jLg/l and 83,000 pg/l in wells WS-1 and WS-3, respectively. Dissolved manganese was detected at 13,000 pg/1 and 3,100 lg/1 in wells WS-1 and WS-3, respectively."

"Cabot Yard, Bacteria Count: Heterotrophic and hexadecane degrading bacteria were detected in well SW-4 at concentrations of 46,000 colony forming units per milliliter (cfu/ml) and 38,000 cfulml, respectively."

"Abutting Properties, Metals/Inorgancis: Total and dissolved iron were detected in well WSA-2 at concentrations of 39,000 ptg/1 and 38,000 pig/l, respectively. Total and dissolved manganese were detected in well WSA-2 at concentrations of 2,800 pg/1 and 2,900 pg/1, respectively."

"Abutting Properties, Alkalinity/Nitrate/Sulfate: Alkalinity (as calcium carbonate) and sulfate were detected in well WSA-2 at concentrations of 520 mg/l and 8.1 mg/1, respectively. Nitrate (as nitrogen was not detected in the WSA-2 sample. Hexadecane bacteria were found at to be lowest in the source area (Cabot Yard) and higher at an abutting property (250 Dorchester Avenue)."

"Abutting Properties, Bacteria Count: Heterotrophic and hexadecane degrading bacteria were detected in well WSA-2 at concentrations of 220,000 cfulml and 230,000 cfu/ml, respectively."

"Product exists at Cabot Yard and within the Pump Station's stormwater collection system. At Cabot Yard, product thicknesses range from less than an inch to almost 6 feet. The product plume is thickest at well WS- 1 and decreases in thickness in every direction from WS-1. Product appears to be migrating in a northerly direction along a large utility corridor in the vicinity of well SW-4. This utility corridor, known as the South Boston Interceptor Trench, contains a 48-inch diameter sewer pipe owned by BWSC. This sewer pipe carries stormwater that is collected over a large portion of South Boston. The pipe is located between approximately 15 to 25 feet below grade and, as such, intersects the groundwater table in the area of product at Cabot Yard. Acting as a preferential pathway, the bedding materials ofthis large sewer line likely contain product and are influencing the shape of the plume as shown on Figure 7. After constructing the South Boston Haul Road and installing numerous utilities and underdrains, a preferential pathway was created south of Cabot Yard that likely acts as a sink. Therefore, as the 48- inch sewer line collects product and carries it via bedding materials towards the north and south, the groundwater sink created by the Haul Road draws the carried product from the sewer line's bedding materials into the Haul Road's stormwater collection system (presumably via underdrains)."

"7.5.1 Enhanced Soil and Groundwater Bioremediation. Enhanced bioremediation involves aerobic biodegradation of petroleum contaminants in soil and groundwater. Aerobic biodegradation involves the use of microorganisms to degrade contaminants to a non-hazardous state, the final end products being carbon dioxide and water. In many cases, bioremediation is naturally occurring in the aquifer. As stated in Section 4.3.3, the results of the bioremediation parameter analyses indicate bioremediation is currently taking place in saturated soils at the Site. Aerobic biodegradation can be enhanced via introduction of oxygen into the aquifer. Injection wells and infiltration galleries are potential methods for distributing oxygen to the areas of contamination."

MBTA, Cabot Yard Facility, 275 Dorchester Ave, Supplemental Phase II - Comprehensive Sit Assessment & Phase III - Identification, Evaluation, and Selection of Remediation Alternatives, Volume 1 of 2 (June 2001).

"Groundwater flow is dictated by factors including hydraulic conductivity of the aquifer and hydraulic gradient across the Disposal Site. Groundwater in the region is presumed to flow to the north/northeast towards the Boston Harbor/Fort Point Channel; however, groundwater at multiple nearby disposal sites has been calculated to flow in a northerly or westerly direction. The closest surface water body to the Site is the Fort Point Channel located approximately 0.2 miles north of the Site. Certain utilities such as water, sewer and stormwater conduits could intersect the groundwater table and therefore have the potential to serve as preferential pathways. The Dorchester Brook Conduit is known to intersect the groundwater table at the Site; while gas and water connections at the Site are likely to be mostly above the water table.

Therefore, based on the immobile nature of lead in groundwater and the distance of the Charles River relative to the Site, it is unlikely for dissolved lead in groundwater to impact nearby surface water bodies. Although there are no Method 1 GW-3 standards for ammonia in groundwater, the concentrations of ammonia detected in groundwater on-Site are not anticipated to pose a threat to nearby surface water bodies based on their distance to the Site.

The South Bay was once 138 acres of wetlands and surface water that was present at the Site and surrounding properties. By 1931, much of the Site had been filled with the exception of Dorchester Brook, which ran north-to-south through the Site along the western edge of what is now 100 Widett Circle. By 1969, the channel had been culverted underground into what is now referred to as the Dorchester Brook Conduit."

VHB oversaw the advancement of a total of 34 soil borings to depths ranging between 14 and 30 feet below grade. The soil borings were advanced between January and November 2022. Soil boring locations were selected to evaluate whether a reportable release of potential COCs had occurred at the property. Concentrations of metals including antimony, arsenic, cadmium, lead, and zinc were detected in excess of the RCS-2 standards in soil samples collected from across the three properties. Lead was detected in excess of the MCP Method 3 Ceiling Limits at soil borings WC4-2 and WC11-11 at 8,460 and 6,210 mg/kg, respectively. Zinc was also detected in excess of the MCP Method 3 Ceiling Limits at soil borings WC4-5 and WC11-5 at 13,600 mg/kg and 16,400 mg/kg, respectively. Concentrations of lead, cadmium, antimony, arsenic and zinc were detected in several soil samples in excess of the typical Concentrations for Soil Containing Coal Ash or Wood Ash Associated with Fill Material.

All groundwater analytical results were below the applicable RCGW-2 thresholds with the exception of dissolved lead and ammonia. Dissolved lead was detected in groundwater samples in excess of the applicable RCGW-2 thresholds at wells MW-9, MW-18, MW-19, MW-23, MW-26 , MW-27, and MW-28. › Ammonia was detected in excess of the RCGW-2 standards for groundwater samples collected from WC-11 and WC-6 at wells MW-23, MW-24, MW-25, MW-26, MW-28, MW-29, and MW-31. The ammonia is believed to be a result of natural decomposition processes in the fill underlying the Site. Bedrock was not encountered.

Soils at the Site generally consisted of a medium to fine sand with materials typical of urban fill such as brick, coal, coal ash, and wood debris to approximately 14 feet below grade. The sand was generally underlain by a layer of native clay and silt. All soil analytical results were below the applicable RCS-2 standards except for lead detected in excess of the RCS-2 standards in two of the soil samples collected at WC-11 at 16-18 and 22-24 feet below ground surface at concentrations of 5,210 mg/kg and 1,020 mg/kg, respectively. All groundwater analytical results were below the applicable RCGW-2 standards with the exception of ammonia detected in MW-23, MW-25, MW-32, MW-28 and MW-31 at concentrations ranging from 17.2 mg/L to 26.2 mg/L.

Based on the observed depth of fill material and debris observed during soil boring advancement and the heterogenous distribution of contaminants of concern, the elevated concentrations of PAHs and metals in soil as well as dissolved lead in groundwater appear to be attributed to the urban fill material used for the filling of South Bay in the 1930s. Additionally, concentrations of ammonia in groundwater are believed to be attributed to the naturally-occurring decomposition processes occurring in the urban fill or remaining organic material associated with the former South Bay. As an intermediate in the nitrogen cycle, ammonia is naturally present in environmental media. However, since ammonia was also historically utilized at the Site for cold storage purposes, the source of ammonia will continue to be evaluated as part of future assessments on-Site.

Based on groundwater sampling conducted during the Phase II ESA in 2022, dissolved lead was detected equal to or in excess of the applicable reportable concentration (RCGW-2) in groundwater in monitoring wells MW-4, MW-9, MW-18, MW-19, MW-23, MW-26, and MW-27. These wells are located in the northern portion of the Disposal Site, but no apparent source area was identified. Lead was not detected in excess of the applicable RCGW-2 standards in any of the monitoring wells sampled during the May 2024 sampling event. Lead is generally immobile and is not expected to migrate. The detections of lead in groundwater at the Site are likely attributed to the presence of Historic Fill.

Additionally, concentrations of ammonia were detected in excess of the RCGW-2 standards in groundwater samples collected at MW-23 through MW-26 during both the October 2022 and June 2024 groundwater sampling events. These monitoring wells are located in the vicinity of the warehouse spaces at WC-11 and WC-6. The warehouses located on these parcels historically included refrigeration systems which require the storage of large volumes of ammonia and glycol. Documented releases of anhydrous ammonia occurred at WC-11 under RTN 3- 35885; however, the release reportedly dispersed into the atmosphere and no residual contamination was identified. Therefore, the elevated concentrations of ammonia in groundwater are likely attributed to natural processes. However, the source of ammonia will continue to be evaluated as part of future Site investigations."

MBTA Widett Circle Properties, Boston, Massachusetts, PHASE I INITIAL SITE INVESTIGATION, TIER CLASSIFICATION & PHASE II SCOPE OF WORK, Release Tracking Number (RTN) 3-38285 (August 9, 2024).

The former South Bay Incinerator property is listed in the SHWS, RELEASE, and INST CONTROL databases in association with the documented release of OHM assigned to RTNs 3-952 3-17174. As early as 1988, an environmental investigation at the property had revealed the presence of metals and petroleum constituents in soil in excess of the applicable regulatory criteria. At the time of this investigation, groundwater contamination was also identified. It was also known that the area addressed by RTN 3-952 was a closed landfill. RTN 3-952 was assigned to the disposal Site in January 1989. The disposal site achieved initial regulatory closure in June 2002 with the submittal of Class A-3 RAO statement and the filing of an AUL. Residual contamination remained at the disposal site, and a Condition of No Significant Risk is maintained by the implementation of the AUL. RTN 3-17174 was assigned to the disposal site in August 1989 when petroleum products were identified in soil at reportable concentrations. RTN 3-17174 was linked to primary RTN 3-952 in January 1999. All following remedial response actions were completed under the primary RTN.
Based on the subsurface assessment activities conducted on-Site, environmental listings at this property have not impacted environmental conditions on-Site.

MBTA Widett Circle Properties, Boston, Massachusetts, PHASE I INITIAL SITE INVESTIGATION, TIER CLASSIFICATION & PHASE II SCOPE OF WORK, Release Tracking Number (RTN) 3-38285 (August 9, 2024).

It should be noted that most soil samples were collected at depths at or near the groundwater table surface. Soil samples saturated with diesel fuel were not submitted for laboratory analysis. Therefore, it is reasonable to assume that diesel fuel saturated soils are present in the same horizontal and vertical distribution. In addition, as described in the previous section, product is likely migrating into the bedding materials of an on property 48-inch sewer line. As these materials carry product towards the north and south, the surrounding soil (in both the vadose and saturated zones) is likely becoming contaminated.
In addition, product appears to be migrating in a northerly direction along a large utility corridor (South Boston Interceptor Trench) in the vicinity of well SW-4. This utility corridor contains a 48-inch diameter sewer pipe owned by BWSC. This sewer pipe carries stormwater that is collected over a large portion of South Boston. The pipe is located between approximately 15 to 25 feet below grade and, as such, intersects the groundwater table in the area of product at Cabot Yard. Acting as a preferential pathway, the bedding materials of this large sewer line likely contain product and are influencing the shape of the plume.
After constructing the South Boston Haul Road and installing numerous utilities and underdrains, a preferential pathway was created south of Cabot Yard that likely acts as a sink. Therefore, as the 48- inch sewer line collects product and carries it via bedding materials towards the north and south, the groundwater sink created by the Haul Road draws the carried product from the sewer line's bedding materials into the Haul Road's stormwater collection system (presumably via underdrains).
Widett Circle Properties, Boston, MA, Prepared by VHB for MBTA, Phase I Initial Site Investigation, Tier Classification, & Phase II Scope of Work (Aug. 9 2024).

"Four test borings ranging in depth from 12 to 17 feet were completed on November 13 and 14, 1985. The fill consisted of a loose to medium dense mixture of fine to coarse sand, fine gravel, and trace silt with varying amounts of cinders, wood and brick. Underlying the granular fill mixture is a layer of dark gray organic silt with trace amounts of wood. At the completion of drilling an observation well consisting of a 2-inch-diameter PVC wellscreen and solid riser pipe was installed in each borehole. A filter of clean silica sand was placed in the annular space around each wellscreen, and a bentonite seal placed 1 to 2 feet below the ground surface. Each well head was equipped with a protective road box to allow for future sampling.% Groundwater levels recorded in each borehole ranged between 5 and 6 feet below the existing ground surface

Soil samples of the fill recovered in each of the borings were screened for volatile organic compounds using an H-N photo ionization detector, Model PI-101. Results of the H-Nu .screening are presented on the boring logs. I general, the results suggest that low concentrations of volatile organic U compounds may be present in fill samples. Based on the H-N screening selected soil samples were also screened for volatile organic compounds using a Century Systems Model OVA-128 portable gas chromatograph with flame ionization detector. Results of the gas chromatograph screening did not indicate the presence of priority pollutant volatile organic compounds., In general, they indicated the presence of methane in fill samples from A-OW-1, A-92-2 and A-OW-4. In addition, samples screened from A-OW-3 and A-OW-4 suggested the presence of low concentrations of weathered oil.

Groundwater samples collected from observation wells A-i-OW, A-2-OW, A-3-OW, 1-4-OW, and G-11-0 were analyzed for pH and specific conductivity was measured using an Orion Research Modell 701A/ digital ionalyzer. An Extech Digital Model 440 I Conductivity Met= was used to analyze specific conductance of the groundwater samples. Test results indicate the pH ranged between 5.72 and 7.44. The specific conductivity of the water samples -ranged between 181 umhos/cm and 2,738 umhcs/cm."

S&I FACILITY SOUTH HAMPTON YARD, BOSTON, MASSACHUSETTS, Evaluation for Chemical Contamination, Prepared for Seelye, Steveason, Value &-Knecht Boston, Massachusetts (Jan. 1986).

"The Cabot Yard property has been operated by the MBTA as a rapid transit line and bus repair facility since 1973. Typical operations at Cabot Yard include train and bus maintenance and repair, fleet vehicle repair, bus storage and signal repair. Typical operations within the CMF consist mostly of transit car maintenance and repair, painting and cleaning. The CMF also includes a wash alley (Track 9) where assembled sets of transit cars (trains) can be washed automatically as they pass through the bay. The MBTA acquired the Cabot Yard property in 1969 and the CMF, Cabot Bus Garage and Maintenance Facility and select ancillary structures were constructed in 1973. Historically, the Cabot Yard property, or portions thereof, had been used as a rail road facility since at least 1875, primarily as part of the Old Colony Railway (OCR) and later the New York, New Haven and Hartford Railroad. The western portion of the property was historically improved by a carhouse, engine house, machine, shop, boiler shop, car repair shop, car paint shop and a coal shed associated with the OCR. The eastern portion of the property historically included tenements, a stone yard and marble works prior to the property’s conversion to a rail yard circa 1875."

"According to the Jacobs Preliminary Geotechnical Report for the Phase 2 Carhouse Improvements, the Site is located above the Cambridge Argillite of the Milford-Dedham zone of southeastern Massachusetts. The rocks of this area are Proterozoic Z to Paleozoic age and consist mainly of gray argillite with various amounts of sandstone and conglomerate. Bedrock was not encountered during the 2017 borings advanced by Jacobs. Reportedly, historical borings completed in 1972 did core argillite bedrock. Historical site borings indicate bedrock is anticipated at a depth of about 110 feet. The Site and surrounding area are locations of historic filling that created much of the land area of Boston in vicinity of Boston Harbor and its inlets and tributaries. The surrounding area was likely low lying wetlands or mudflats prior to filling. The period of filling of this particular area is not known at this time."

"The subsurface conditions at the Site generally consist of loose urban fill overlying a thick layer of silt and clay, with a till layer at approximately 92 to 100 feet below grade. Approximately 10 to 18 feet of granular fill was encountered in most borings. The fill layer was generally very loose to medium dense and consisted of black/ light brown sand with varying amounts of gravel and silt. Various amounts of foreign material (brick fragments, slag, and coal ash) were also encountered. Visual observations of soil samples revealed sandy fill material comprised of black to dark brown, fine to coarse sands with some fine to coarse gravel and little silt. Varying amounts of brick, coal slag, wood and little coal ash were observed within the soils, typical for urban fill deposits. Up to approximately 72 feet of silt and clay was encountered below the fill. This layer typically consisted of a gray, silty clay. The top 17 to 40 feet of this layer had thin interbedded layers of fine sand. Generally, the top 7 to 25 feet was stiff to very stiff, while up to 60 feet of the bottom portion of the layer was very soft. Glacial till was encountered between about 92 and 100 feet below existing ground surface. The till generally consisted of hard, gray, silty clay and sand with varying amounts of gravel. The thickness of this layer was not determined since the 2017 geotechnical borings did not penetrate through the fill into the underlying bedrock. Groundwater monitoring to date has revealed groundwater ranging from 6.2 to 6.8 feet below ground surface (bgs). Due to the difficult nature of installing groundwater monitoring wells due to underground obstructions, only two monitoring wells have been installed to date at the Site. Empirical determination of groundwater flow direction could not be made. Additional monitoring wells are proposed to be installed in the future and a groundwater elevation survey will be completed at that time"

PHASE I INITIAL SITE INVESTIGATION & TIER CLASSIFICATION SUBMITTAL, Cabot Maintenance Facility 275 Dorchester Avenue South Boston, Massachusetts, DEP Release Tracking Number 3-34777, Prepared For Massachusetts Bay Transpiration Authority, (February 2019)

"The MBTA Cabot Bus Yard has operated as a public transportation maintenance facility for over 135 years. The vehicle maintenance/repair facility is open on the first floor with all offices located on the second floor. The Disposal Site is shown on Figure 2 and is entirely covered by building foundations and pavement. Soil at the Site consists of silty fine to medium sand or sandy fill over a lower confining layer of Boston blue clay. The fill is typically about 10 feet thick and the Boston blue clay is approximately 30 feet thick. A layer of silt and clay at approximately 10 to 13 feet below ground surface (bgs) exists over the majority of the Site and, as determined in the Class C-2 Response Action Outcome (RAO) (W&S, 2007), acts as a semiconfining layer with light non-aqueous phase liquid (LNAPL) present below it. Bedrock was not encountered during any investigations performed at the Site.

"The groundwater table at the Site varies between nine and 20 feet bgs. A semi-confining layer is located at 10-13 feet bgs. The majority of groundwater at the Site is present below this confining layer. Historically, in portions of the Site, deep utilities (now abandoned), when after constructed and backfilled with high-permeability sand, have acted as preferential migration and collection pathways for the LNAPL; however, groundwater has been the primary migration mechanism for LNAPL. Groundwater at the Site flows to the east/southeast, towards Pump Station No. 3. There are no drinking water supplies located in the vicinity of the Site."

PERMANENT SOLUTION WITH CONDITIONS STATEMENT, MBTA Cabot Yard, 275 Dorchester Ave., South Boston, Massachusetts, MassDEP Release Tracking Number (RTN) 3-3096 (June 2025).

"The work scheduled in the Cabot Cove area includes the building of a seawall as part of CO9B1 and landscaping and a walkway, which is proposed to be done under C09D2. Due to the depth and location of the excavation and landscaping, the area required additional characterization in order to attain adequate ROWARS coverage. In addition, a Clearance Area previously identified in the C09A7/CO9A8 contracts has been redefined. This addendum report presents the rationale and approach used to define the extent of the Clearance Material. Figure 1 shows the boring locations and the revised Clearance Area. Appendix A contains the boring logs and the survey information for the ROWARS borings discussed in this addendum report. Appendix B contains a summary of the data associated with the ROWARS borings."

Borehole Log & Results:

UA-SB-93 (1995): 1'-3" Dry, medium dense dark brown. coarse to fine SAND; 7'-9' moist loose brown/grey course to fine SAND and SILT, trace gravel; 12'-14' moist, soft, grey SILT; little course to fine sand, trace wood, trace shells; 15'-17' wet, very soft, grey CLAY, some silt, trace course to fine sand, trace shells.
UA-SB-94 (1995): 1'-3- Dry, medium dense. Brown, coarse to fine SAND and GRAVEL; 5'-7' Dry, medium dense. Brown-grey, coarse to fine SAND and GRAVEL. little brick, trace silt, trace clay. 10'-12' Moist. loose. Black/grey coarse to fine SAND and SILT, trace clay. trace shells, trace wood. 15'-17" Wet, soft, grey SILT. little coarse fine sand, little peat, trace wood. trace shells, trace clay.
UA-SB-96 (2002): 1' - 3': Dry, brown, medium-fine SAND, little course-fine gravel, trace silt and red brick; 5' - 7': Moist, dense, brown, medium-fine SAND, little fine gravel, trace glass, wood and red brick; 10' - 12': Moist, dense, grey brown, medium-fine SAND, some silt, trace clay; 15' -17': Wet, grey, SILTY-CLAY
UA-SB-97 (2002): 1'- 3' - Dry, brown, medium-fine SAND, little course-fine gravel, trace silt and red brick; 5'- 7' - Dense, brown black, medium-fine SAND, little fine gravel, trace silt; 1' - 12': Medium dense, grey-black SILTY CLAY, some fine sand,
trace organics; 15' - 17: Wet, grey CLAY, some silt, trace medium-fine sand.

Central Artery (I-93)/Tunnel (1-90) Project, ROWARS Contract 97159-MO26G, Construction Contracts CO9B/CO9D2, Cabot Cove Characterization/Clearance Report, LO-CAT-02-26G-0372 (November 21, 2002).

1994 BORING LOG AND WELL CONSTRUCTION

SW-1 (1994): 4'-8' FILL: Tan to brown fine to coarse Sand, little gravel, trace silt, clay, SR brick, asphalt; 8'-14' FILL; Yellowish-tan clayey Silt. trace sand and gravel. Samples moist; 14'-16' Gray to black clayey organic Silt, some shells and plant matter. Organic odor. Samples moist; 16'-21' Tan to gray interlayered silty fine sand and trace clay. Samples wet; 21'-23' Gray fine to medium Sand, little coarse sand.
SW-2 (1994): 2'-11' FILL; very dense dark brown to black Sand and Gravel, trace brick and concrete. Light gray to black fine to
coarse Sand, little gravel. some to trace cinder/ash, and trace brick. 10'-12' Dark brown organic Silt (peat) with root/plant matter, little fine sand; 12'-18' Gray interlayered silty fine Sand mottled brown Silt. Samples damp to moist with some petroleum odor. 17'-24' Gray medium Sand, traces of fine and coarse sand. Samples wet with strong petroleum odor.
SW-3 (1994): 1'-12' FILL; Brown to grayish-brown silty Sand and Gravel, little brick. glass, wood and cinders at various depths; 12'-16' Gray silty fine to coarse Sand. some mottled brown silt, trace gravel. Appears to be reworked native material. Samples damp; 16'-23' Gray interlayered silty fine to medium Sand, mottled brown Silt, cohesive clayey silt, and fine to medium sand. Dark gray fine to medium Sand lense with strong diesel odor at about 20 feet; 23'-25' Tan fine to coarse Sand.
SW-4 (1994): 1'-11' FILL; Brown to grayish-brown silty Sand and Gravel, few cabbies, little brick. glass, wood and cinders at various depths; 11'-15' Gray silty fine to medium Sand. trace clay, some brown mottiing; 15'-17' grey to yellowish-grey interlayered, mottled brown Silt, medium to coarse Sand, silty fine Sand. and silty clayey fine to coarse sand; 17'-24' Tan loose dry medium Sand. Sample dry. Tan fine to coarse Sand. Sample wet. Tan silty fine to medium Sand interlayered with clayey Silt and fine Sand; 24'-28' Gray interlayered silty fine to medium Sand, and mottled brown - Silt with little fine sand. Two 2" lenses of gray silty Clay @ 27 feet.
SW-6 (1994): 1'-5' FILL; Tan to black fine to coarse Sand with some gravel, trace brick; 5'-8' Gray silty fne to medium Sand.
Damp with some organic odor; 8'-15' Dark gray, mottled black and brown organic clayey Silt. Little plant/ root matter, trace shells. Organic odor. Samples moist; 15'-18' Very slight petroleum odor. Dark gray fine to coarse Sand with little gravel and shells. Gray silty fine to medium Sand. 2" stiff gray mottled brown Silt. Gray silty fine to medium Sand.
SW-7 (1994): 1'-5' FILL Gray to dark gray silty Sand little gravel, trace brick and glass; 5'-10' FILL; Dark brown to olack sandy
angular gravel [old RR ballast/bed], FILL Tan silty Sand and red brick. little clay and gravel in sand. FILL: Dark brown silty Sand, little gravel, wood. glass, cinders; 10'-17' Brownish-gray fine to medium Sand. little silt and gravel. Dark brown fibrous organic silty Sand [peat) grading to grayish-brown sandy Silt with plant fibers. Gray interlayered silty fine to medium Sand, mottled brown organic Silt, trace clay and gravel; 17-25' Tan interlayered fine to coarse Sand. clayey Silt, silty fine Sand, and fine to medium Sand.
SW-8 (1994): 1'-10' FILL; Tan medium to coarse Sand and Gravel. FILL; Tan to black silty fine to coarse Sand, some gravel, little to trace coal cinders/ash, trace brick, and wood; 9'-11' Black to brown rooty fine to medium Sand. some organic silt, little organic odor; 11'-13' Gray clayey mottled brown Slit, little fine to coarse sand, trace rooty matter. Sample damp; 13'-16' Gray to tan medium Sand, little fine and coarse Sand and gravel; 16'-25' Grayish-tan interlayered fine to coarse Sand. mottled brown
clayey Silt, silty fine to medium Sand. Samples wet.

Technical Document in Support of Tier Classification, MBTA Cabot Yard, 275 Dorchester Avenue, South Boston, Massachusetts, DEP RTN 3-3096 (August 2, 1996).

2001 BORING LOGS:

WSA-1 (2001): 1'-5' Dark brown, to brown to gray medium SAND, some coarse Gravel, Dry; 5'-7' Brown medium SAND some wood and brick, trace coal and ash, dry; 10'-12' Gray Silty CLAY some fine-medium Sand, trace Clay, Wet; 15'-17' Gray medium SAND, some fine.
WSA-3 (2001): 1'-5' Dark brown medium-coarse SAND and fine GRAVEL, little medium brown Sand, Dry; 5'-7' Tan medium-coarse SAND, Dry; 10'-12' Gray CLAY with lenses of fine Sand and Silt, trace tan Sand Moist; 15'-17' Black and gray fine SAND, gray SAND, little tan Silt and fine Sand, Wet.
WS-1 (2001): 1'-4' dry, very dense, brown, medium, SAND some Gravel, trace coarse Gravel; 4'-6' moist, medium dense, dark brown, fine to medium SAND, some Gravel, trace Silt; 9'-11' moist, loose, gray, SILT, some Clay, trace Gravel, trace Ash; 14'-16' wet, medium dense, gray and brown, fine SAND, some Silt, trace Clay; 18'-20' wet, dense, brown, fine SAND, some Silt, trace Clay; 23'-25' wet, dense, fine SAND, some Silt, trace Clay.
WS-9 (2001): 1'-5' Dark brown medium SAND some fine-coarse Gravel, Dry; 5'-7' Dark brown and black medium coarse SAND, trace Silt, trace fine-coarse Gravel; 10'-12' Black medium-coarse SAND, some fine Gravel, Wet; 15'-17' Dark gray medium-coarse SAND trace fine Sand, Wet
WS-10 (2001): 1'-3' Brown medium SAND to dark brown medium Sand, trace Brick; 3'-7' Brown medium-coarse SAND some light brown and dark brown medium-coarse Sand, little Brick Dry; 7'-11' Dark brown and gray fine SAND and SILT, some black medium coarse Sand, Moist; 11'-15' Gray fine SAND and SILT little Clay, Wet; 15'-19' Gray CLAY, Wet.
WS-11 (2001): 1'-3' Brown medium SAND, some black medium-coarse Sand, trace fine Gravel, Dry Black medium-coarse SAND little Brick, Dry; 7'-11' Gray SILTY CLAY grading into tan medium-coarse Sand, some black medium Sand, Dry; 11'-15' Tan medium SAND grading into coarse Sand, Dry; 15'-19' Tan fine-medium SAND some Silt Clay, Wet at 16; 19'-23' Tan fine SANO and SILT little, into Silty Clay, Wet.
WSPS-1 (2001): 1'-4' light Brown medium SAND some dark brown/black medium-coarse Sand, some fine-coarse Gravel Little Silt, Dry; 4'-8' Gray Silty CLAY, some brown fine -medium Sand, Moist in Tip; 8'-12' Gray SILTY CLAY fine medium Sand little fine Sand and Silt Wet; 12'-15' Gray to Brown fine SAND and SILT, some medium Sand, into Silty Clay, Wet.
WSPS-2 (2001): 1'-4' Brown fine SAND and SILT, some, brick, little to dark gray Silty, Clay, Dry; 4'-8' Black organic SILT little blue/gray Clay, Dry; 8'-12' Blue/Gray CLAY little brown fine medium Sand, some fine Gravel Wet; 12'-15' Brown medium SAND some reddish brown medium-coarse Sand, Wet.

Massachusetts Bay Transportation Authority, MBTA- Cabot Yard Facility, 275 Dorchester Avenue, South Boston, Massachusetts, RTN 3-3096 and 3·19247, Supplemental Phase II - Comprehensive Site, Assessment and Phase Ill - Identification, Evaluation, and Selection of Remedial Alternatives, Volume 1 of 2, Text, Figures, Tables, Appendices A,B, and C (June 2001).

Soil Disposal Characterization (10/1/2019 0‐5'; 5/22/2020 5‐7'; 7/20/2020 7'): Conductivity ‐ Soil Matrix 233, 458, 601 umhos/cm; Soil pH at 25C 7.02, 7.48, 8.89; Lead 207, 264, 190 mg/Kg

Dewatering Sediment Disposal Characterization (12/30/2020 CMF‐F T‐SP1): Conductivity ‐ Soil Matrix 1,690 umhos/cm; pH at 25C ‐ Soil 11.2; Arsenic 80.2 mg/Kg; Lead 1,680 mg/kg; TCLP Lead 7.61 mg/L

Subsurface Dewatering Analytical Summary: Total Suspended Solids, 6/1/2020 CMF‐F‐EP 1,400 mg/L

PHASE I – INITIAL SITE INVESTIGATION REPORT AND TIER CLASSIFICATION SUBMITTAL MBTA Contract No. R44CN02, Cabot Yard Rebuild & Maintenance Facility Improvements, South Boston, Massachusetts (Release Tracking Number 3-36307)

SEX 80ft blue clay and 5ft of sediment, then above bricks, timbers, woods and landfill
The Boston Globe Sun, Dec 15, 1996 ·Page 319

Widett Circle Properties, Boston, MA, Prepared by VHB for MBTA, Phase I Initial Site Investigation, Tier Classification, & Phase II Scope of Work (Aug. 9 2024).
MW-12-13 : 4-14 ft is wet, moist, black, grey, shells (2022)
WC6-8: 4ft-12ft wet, moist, black, grey, shells; 8-14 ft “strong petroleum odor”; clay at 14 ft (2022)
MW-11 8ft-14ft No Recovery (2022)
MBTA, WC4-2, 8-18ft, brown sand pebbles, moist, trace wood, coal, and shells (2022)
MBTA, WC6-5 , 6-8ft, Debris and wood in sleeve (2022)
MBTA MW-17, 2-4 brown/grey sand/clay with “streaks of orange”; 12ft-20ft coal; 12-22 black, wet; 20-22ft black and grey clay

REC #2 – Historical uses of the Site parcels including the former presence of South Bay (and associated fill of unknown origin), railroad tracks, and poor housekeeping.
South Bay that was filled in by the 1930s.
Widett Circle Properties, Boston, MA, Prepared by VHB for MBTA, Phase I Initial Site Investigation, Tier Classification, & Phase II Scope of Work (Aug. 9 2024).

Bacteria Count: Heterotrophic and hexadecane degrading bacteria were detected in well WSA-2 at concentrations of 220,000 cfulml and 230,000 cfu/ml, respectively. Heterotrophic and hexadecane degrading bacteria were detected in well SW-4 at concentrations of 46,000 colony forming units per milliliter (cfu/ml) and 38,000 cfulml, respectively.
Widett Circle Properties, Boston, MA, Prepared by VHB for MBTA, Phase I Initial Site Investigation, Tier Classification, & Phase II Scope of Work (Aug. 9 2024).

During groundwater Monitoring Well inspections in May 2018 and Feb. 2019, multiple wells were found to be filled with water, well above the later depth to water points. Multiple wells noted "well was filled to the top with water" for both visits but then sunk to a lower elevation by May 2019 (DPE-20, 9.97; DPE-21, 19.16; DPE-26, 15.15). Some wells (DPE-1, DPE-13) noted this on all 2018-2019 visits. Two wells were marked "well was filled to the top with water" in 2018 only but then depth to water lowered by Feb. 2019 (DPE-5 at 16.29, then 17-18' later in 2019).

PERMANENT SOLUTION WITH CONDITIONS STATEMENT, MBTA Cabot Yard 275 Dorchester Ave. South Boston, Massachusetts, MassDEP Release Tracking Number (RTN) 3-3096 (June 2025).

MBTA (2001)

1888

FORT POINT CHANNEL

The depth to water in the installed observation well ranged from 7.0 ft to 7.6 ft below the ground surface. In addition Boston Wharf Company has installed several observation wells in the area. These wells indicate that the water levels range from El. 5 to El. 9 (5 ft to 14 ft below ground surface) across the site.
Groundwater levels may fluctuate due to variations in season and precipitation, leakage into or out of existing utilities and utility bedding materials, adjacent construction activities, and other environmental effects. As a results water levels encountered during construction may vary from those recorded in the observation well and borings during the observation period.
Fort Point Channel Combined Sewer Overflow Control Project, BWSC Contract No. 95-206-014 (2006)

"According to geotechnical borings performed by the City, the project area is composed of soft clay and mud fill to approximately 25-30 feet below the surface and below that is composed of alternating layers of hard and soft compressible clays, mixed with sporadic sand and shell lenses to approximately 70 feet below existing grade (City of Boston 2020). geotechnical borings performed by the City, the project area is composed of soft clay and mud fill to approximately 25-30 feet below the surface and below that is composed of alternating layers of hard and soft compressible clays, mixed with sporadic sand and shell lenses to approximately 70 feet below existing grade (City of Boston 2020)."
The project area and 100 Acre Master Plan area are primarily characterized by built urban infrastructure with minimal wildlife habitat. The habitat in the project area is limited to landscape vegetation, including street trees, along the Harborwalk and in Binford Street Park.
The proposed project area consists of two wetland resource areas protected by the Massachusetts Wetlands Protection Regulations (310 CMR 10.00), including coastal bank and land subject to coastal storm flowage. Each of these resource areas is described in detail below. Estimated habitats of rare wildlife, essential fish habitat, species protected under the Endangered Species Act, and Chapter 91 Waterways jurisdiction are also discussed below. The coastal bank present at the site is primarily comprised of the wall of Fort Point Channel, running from the parking lot at the southern end of the channel to t he Summer Street Bridge to
the north (Figure C-3). Along approximately the middle of the coastal bank, around the SP+ parking lot, the location of the top of the bank shifts slightly landward. At this location, there is not a steep channel wall, but rather a gentler slopping cobble and riprap shoreline (Figure C-4). Cobble and riprap are bordered by grass and then a concrete sidewalk in the landward direction. An existing outfall and concrete headwall structure is within this portion of the bank. The entire length of the bank within the project area is approximately 2,380 feet. This resource area provides a buffer between the channel and inland areas from storm damage and flooding. The bank does not serve as a sediment source to any nearby coastal beach or dune systems. The top of the coastal bank within the project area was delineated using the most recent aerial imagery from MassGIS (2019) to identify the location of the channel wall.
The project area is located within a special flood hazard area (Zone AE 10) subject to inundation by the one percent annual chance flood, as shown on the FEMA Flood Insurance Rate Map panel 25025C0081J dated March 16, 2016 (Figure C-5). The project area is within the Boston Harbor watershed and the Boston Harbor Coastal Drainage Area (MassDEP 2014). Water drains from the project area into the Fort Point Channel. There are 14 stormwater and combined sewer outfalls into the Fort Point Channel that carry stormwater runoff from the larger neighborhood under the project area into the Fort Point Channel immediately adjacent to the project area. Stormwater that runs off impervious surfaces adjacent to the channel, such as parking lots and buildings, is also conveyed to the channel either through surface runoff or drainage systems. The project area is located within the City of Boston Waterfront Area, which is the portion of the buffer zone that extends twenty-five (25) feet horizontally from the edge of the coastal bank.
According to the NMFS EFH online mapping tool, the Fort Point Channel potentially contains EFH for 25 fish species including, but not limited to, winter flounder, Atlantic wolffish (Anarhichas lupus), Atlantic cod (Gadus morhua), and yellowtail flounder (Limanda ferruginea). No Habitat Areas of Particular Concern (i.e., high-priority areas for EFH conservation) or special aquatic sites (e.g., submerged aquatic vegetation, saltmarsh, coral reefs) are in the project area (NMFS 2020).
According to the National Oceanic and Atmospheric Administration (NOAA) Fisheries Greater Atlantic Region Section 7 Mapper, accessed September 7, 2021, there are two ESA-listed species of fish and four species of sea turtles that occur, or have the potential to occur, in the Fort Point Channel: Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus), shortnose sturgeon (Acipenser brevirostrum), loggerhead turtle (Caretta caretta), leatherback turtle (Dermochelys coriacea), green turtle (Chelonia mydas), and Kemp’s ridley turtle (Lepidochelys kempii). The presence of listed species in the project area is very unlikely because the Fort Point Channel is enclosed and highly developed (R. Mesa, NOAA, personal communication, September 8, 2021).
The project area is characterized by large amounts of buried infrastructure including electrical lines, communication conduits, industrial raw water intakes and outfalls from the Gillette facility, stormwater infrastructure, and the I-90 Massachusetts Turnpike, which is buried approximately 25 feet underground (City of Boston 2020). The construction of the turnpike The project area is characterized by large amounts of buried infrastructure including electrical lines, communication conduits, industrial raw water intakes and outfalls from the Gillette facility, stormwater infrastructure, and the I-90 Massachusetts Turnpike, which is buried approximately 25 feet underground (City of Boston 2020). The construction of the turnpike. The stormwater infrastructure includes 14 outfalls in the project area that flow into Fort Point Channel. Stormwater infrastructure in South Boston is part of a combined sewer overflow system that collects rainwater runoff, domestic sewage, and industrial wastewater in the same pipes (Massachusetts Water Resources Authority 2021). Thus, when stormwater levels are too high, such as when flooding occurs, the combined sewer overflows and can carry human and industrial waste into waterways or get backed up and flood sewers, streets, and buildings."

Environmental Notification Form, Proposed City of Boston Resilient Fort Point Channel Infrastructure Project for Boston Planning & Development Agency, Woods Hole Group, Inc, (December 2021).

"In 1872, the Great Boston Fire consumed approximately 800 buildings over sixty acres in downtown Boston. Ash and debris from the cleanup was used to fill tidelands along Fort Point Channel. In-1877, this filled land was developed by the Roxbury Gas Light Company for use as a plant to manufacture natural gas from coal for use in the City of Boston. The manufactured gas was stored in a circular building that housed a gas holder. This building was constructed through the ash-containing fill and deep into the impermeable Boston blue clay beneath. This gas holder and the approximate 0.4 acres of filled tideland on which it is located.
Three contaminant regimes were identified at levels exceeding Reportable Concentrations: 1. diesel fuel on the southern portion of the Property; 2. mineral spirits along the northern boundary of the Roundhouse Property; and, 3. fill containing ashrelated
contaminants, such as polycyclic aromatic hydrocarbons (PAHs), lead, and aromatic fractions of hydrocarbons. The diesel fuel and mineral spirits originated on the adjoining properties. The ash-related contaminants are related to filling that occurred over a century ago."

Phase I Initial Site Investigation Report & Method 3 Risk Characterization, 8 Gerard Street, Boston (Roxbury), MA, DEP RTNs: 3-18967, 3-3774, 3-18421, ENSOL (1999).

An effort was made to identify groundwater flow paths by performing a textural analysis of the clay/silt fill, the sand lenses located at and below the water table, and from the underlying native soil above the Boston blue clay The laboratory analysis is presented in Appendix E and summarized in Table 7. The particle size analysis indicates that a narrow region of soil at a depth of approximately 10
feet below grade is quite permeable. It is evident from the boring logs that this unit is not homogeneous, and that the permeable samples were collected from narrower lenses over a depth interval of approximately 1.5 feet spanning the water table. This sand-lens
containing unit is overlain and underlain by essentially impermeable soil. The risk estimates derived in the foregoing analysis as a consequence of hypothetical or actual exposure to PAHs and metals in fill on the Roundhouse Property should be viewed in light of the observation that the levels are consistent with fill found in the area. Soil texture is an important soil property because it controls, in part, the rate at which water and other fluids flow through the soil, as well as the amount of fluid retained by the soil. The organization of an aquifer into layers with recognized textural variation is important because this level of organization has a profound effect on the fate of chemicals released to the subsurface
8 Gerard Street, Roxbury, MA ENSOL, Inc. I September 1999, page 22

The vicinity of the Roundhouse Property was formerly the South Bay tidal area, which was filled in the 1800s. Some of this fill might have included debris from burnt buildings.7 In this part of the City of Boston, the soil lithology consists of fill overlying shallow marine sediments or salt marsh sediment, which is underlain by the Boston blue clay.
The central portion of the Site is improved with a circular building, known as the Roundhouse, that is approximately 105 feet in diameter and 55 feet in height. The building extends approximately 24 feet below grade into Boston blue clay, and has been filled to approximately 12 feet below grade, where the current basement floor is located. The building is currently undergoing a gut renovation for use as a hotel. A small loading dock I addition to the southwest of the Roundhouse has been recently demolished. Narrow bands of land along Gerard Street and Massachusetts Avenue were paved with asphalt or granite, and vegetation has been recently cleared from the southern portion of the Site.
The round building ("Roundhouse") improving the Site was constructed in the late 1800s for use as a gas holder for a manufactured gas plant (MGP) that was located several hundred feet to the northeast, and was used as such for approximately a decade until circa
the turn of the century. After use as a gas holder, the Boston Consolidated Gas Co. used the Site for storage from the 1910s through the 1930s. After use by the Boston Consolidated Gas Co., the Site appears to have been used primarily for storage by various trucking concerns and distributors.
Immediate Response Action Completion and Downgradient Property Status Opinion, 8 Gerard Street, Boston (Roxbury), MA, DEP RTNs: 3-18967, 3-3774, 3-18421, ENSOL (1999).

4.02.2 Organic Deposit An organic deposit was encountered in HA-FPCI5 at a depth of 13 ft below ground surface. The boring was terminated at a depth of 15 ft and the layer was not fully penetrated. The deposit consisted of medium stiff SILT with roots.
4.02.3 Estuarine Deposit Estuarine deposits were encountered in borings HA-FPCO9 and HA-FPC17. The deposit ranged from stiff SILT to medium stiff sandy CLAY.
4.02.4 Marine Deposit Marine deposits were encountered in boring HA-FPCO5, HA-FPCO7, and HAFPC-17. The marine deposit ranges from of soft lean CLAY to medium stiff SILT to medium dense SAND with silt. Trace shells, roots, and other organic material was encountered.
Fort Point Channel Combined Sewer Overflow Control Project, BWSC Contract No. 95-206-014 (2006)

Estuarine/Organic Deposits: sandy organic silt, silt and peat. This unit varies in composition across the site, and is described as peat and silt or organic silt. The peat and silt layer ranges in thickness from four to 24 feet, and the organic silt layer ranges from 11 to 26.5 feet thick.
Marine Clay: clay with partings, lenses and layers of silt and fine sand. The top of clay was encountered at depths ranging from 18 to 39 feet and ranges in thickness from 0 to 35.5 feet.
Bedrock: consists of the Cambridge Argillite member of the Cambridge formation, which includes argillite, tuffaceous argillite and diabase. The argillite consists of fine-grained, very thinly bedded layers of silt- and clay-sized clasts. The tuffaceous argillite contains fine- to medium-grained volcanic siliceous fragments within the siltclay argillite matrix. A diabase dike was encountered in one boring. The top of bedrock was encountered at depths ranging from 57 to 113 feet, with an east-west trending bedrock trough defined in the western portion of the site parallel to the southern end of Fort Point Channel. Typically the upper ten feet of bedrock is moderately to highly fractured and weathered. Bedrock competence generally increases with depth. Hydraulic conductivity of this unit was measured to range from 3.3 x 10-4 cm./sec to 8.9 x 10-5 cm./sec
Groundwater at the site has been characterized as consisting of a shallow and deep aquifer separated by a clay layer. The shallow aquifer is located in the fill and estuarine/organic deposit layers, and the deep aquifer is located in the till and bedrock layers. Regional groundwater flow in the shallow aquifer is generally in a northerly direction. However, the effects of the MHD's casting basin pumping activities, tidal fluctuations and buried utilities affect flow patterns locally. The low gradient and tidal fluctuations in the upper aquifer results in a low net movement of groundwater in this interval. Regional groundwater flow in the deep aquifer is generally northwestward. However, the effects of the MHD's casting basin pumping and recharge activities affect deep groundwater flow patterns particularly in the northern portion of the site.
Throughout the site, the clay layer separates the shallow and deep aquifers and impedes vertical groundwater flow between them. However, the Franki piles that support Building Z penetrate the clay layer and likely act as conduits for transport of both dissolved and DNAPL contamination to the underlying till and bedrock layers.
TCE and 1,2-DCE are located in the deep aquifer east, beneath and west of Building Z.
Deep Aquifer TCE and 1,2-DCE exist in the deep aquifer. These compounds have been detected predominantly west of Building Z. Based on existing data, the axis of the plume appears to trend in a northwesterly direction from the former dry well to well MW801B. A bedrock trough trends in a westerly direction northwest of the former dry well source area. A 35-foot decrease in bedrock surface elevation occurs between the source area and the bottom of this trough in the vicinity of MW801B. The bedrock trough is thought to be fracture controlled, which is supported by low rock quality designations (RQDs), for bedrock cores collected along its axis. Therefore, TCE detected in the MW801B/MW801T wells is likely due to hydraulically-controlled dissolved-phase contaminant transport through till and highly-fractured shallow bedrock down the slope to the trough resulting from DNAPL closer to the source area. A downward vertical gradient exists between wells MW801T and MW801B, supporting this theory.
Phase III Remedial Action Plan Gillette South Boston Manufacturing Center, RTN 3-11312 29 (December 1998)

Boston Inner Harbor State Waterbody ID: MA70-02
303(d) Listed: Yes
Year Reported: 2022
303(d) List Status: EPA Interim Action
Other Years Reported: 2014, 2016, 2020
Organization Name (ID): Massachusetts (MA_DEP)
What type of water is this? Estuary (2.56 Square Miles)
Where is this water located? From the Mystic and Chelsea rivers, Chelsea/Boston, to the line between Governors Island and Fort Independence, Boston (East Boston) (including Fort Point, Reserved and Little Mystic channels).

010900010704
Charles River-Frontal Boston Harbor
INNER BOSTON HARBOR / FORT POINT CHANNEL (MA70-02)
Pollutants Potentially Related to Impairment: Chemical Oxygen Demand (COD) | Coliform, fecal, colony forming units | Enterococci | Nitrogen, total (as N) | Phosphorus, total (as P) | Solids, total suspended | pH
Watershed with ESA-listed Aquatic Species?: Yes

doneyles.com

A very large erratic boulder is incorporated into its base in the Fort Point Channel at the MBTA Silver Line crossing (Leifer, 2006) During dredging for the immersed tube placement, a 6 by 6 by 2.4 meter (20 by 20 by 8 foot) glacial erratic boulder was found at the clay-till contact and had to be broken up in place before dredging could be completed. Leifer, A.L., 2006, tunnel information for new Silver Line, written communication, March, 31, 2006, 1 p.

Borings begin to study Big Dig sinkhole near South Station, October 18, 2011 https://www.boston.com/uncategorized/noprimarytagmatch/2011/10/18/borings-begin-to-study-big-dig-sinkhole-near-south-station/
State contractors are burrowing the first of four 135-foot-deep holes near South Station to remove earth that will provide clues about the cause and size of a possible sinkhole beneath one of the Big Dig tunnels. The earth samples should also provide information about how to plug the cavity. During the summer, state highway officials said the void could possibly be as large as the tunnel itself — but that does not mean they believe it is anywhere near that large, the state’s top highway official said today.
“There’s been a little bit of an exaggeration,’’ said Frank DePaola, administrator of the Department of Transportation’s Highway Division, standing on land above the tunnel. “We don’t even know that there is a hole. We know that the ground has settled.’’
To construct the Interstate 90 Connector Tunnel linking the end of the old I-90 through South Boston to the Ted Williams Tunnel, Big Dig contractors a decade ago chemically froze the earth on the downtown side of Fort Point Channel, to keep the ground from caving and leaking, and to allow MBTA and Amtrak trains to continue running overhead. Engineers expected the ground to settle slightly from thawing but were startled to discover that the ground between the tunnel and the railroad tracks was settling at about an inch a month, or about eight feet over eight years, which they filled with gravel. Additional study suggested the thawing was even more widespread and may mean the soil has thawed all the way to the bedrock, well below the highway tunnel. The Department of Transportation publicly disclosed that issue over the summer, amid controversy over the speed and thoroughness with which it had revealed the extent of a separate problem afflicting tunnel light fixtures. “We decided we would just make public all the information that we have on the latent issues remaining from the Central Artery/Tunnel,’’ said DePaola, referring to the formal name for the Big Dig. The thawing could mean that a gap has opened deep below ground running the length of the tunnel — that is unlikely, but even then the tunnel would hold, because it is built like an underground bridge, DePaola said. A state consultant and a separate federal review affirmed the tunnel’s safety, he said. Now the state is boring four five-inch wide core samples 135 feet down to try to determine the cause and extent of any settling as well as how much grout should be pumped in to solidify the thin or missing soil below and around the tunnel. Contractor New Hampshire Boring must first dig through more than 50 feet of surface fill before reaching the layer of Boston Blue Clay soil, where continuous two-foot samples will be extracted until striking bedrock – technically, Cambridge Argillite – another 80 feet later.The contractor is digging one hole along the outside of the eastbound barrel of the I-90 connector tunnel and three holes between the eastbound and westbound barrels of the connector. Work on the first hole, in the parking lot behind Boston’s main post office, began last week, and all four borings should be done by mid-November. Laboratory analysis and conclusions should be ready this winter, DePaola said. He called public confidence the department’s primary concern. “We want to make sure that people are confident, so we will find out what the issue is, and we will treat the soil to give everybody an assurance that there are no latent concerns underground,’’ he said.

FOURTH ST / TRAVLER ST (AT EAST BERKLEY ST / ALBANY ST) & GILLETTE

Groundwater flow was “presumed” to be to the northeast, towards Fort Point Channel and the Boston Harbor. 3-0050262
Boston Inner Harbor, URAM COMPLETION, Boston, Massachusetts, RTN 3-50561 ().
Mass Ave Connector/Frontage Road. Prior use: "green space/park area and/or stormwater drainage area". 10ft deep black, fine-to-coarse sand containing significant amounts of brick, glass, wood, and traces of coal and coal ash. "The identification of coal and coal ash confirms the presence of urban fill material"

1.3.2.1 RTN 3-38454
During initial due diligence programs at the Site, polycyclic aromatic hydrocarbon (PAH) compounds, specifically benzo(a)pyrene, biphenyl, and dibenz(a,h)anthracene, total petroleum hydrocarbons (TPH) and extractable petroleum hydrocarbons (EPH), specifically C11-C22 Aromatic Hydrocarbons (adjusted), C9-C18 Aliphatic Hydrocarbons, 2-methylnaphthalene, and lead were detected in soil at concentrations exceeding the applicable RCS-1 Reportable Concentrations. The lead and the PAH compounds are exempt from reporting as they are emanating from coal, coal ash, or wood ash described in the test boring logs resulting from historic site filling; however, the petroleum-related compounds EPH carbon range C11 to C22 and 2-methylnaphthalene are reportable and could be related to unknown source of heating oil from a former or existing underground storage tank (UST) and are considered a Reportable
Condition under the MCP. Accordingly, a Release Notification Form (RNF) was submitted on 15 November 2023 for the C11 to C22 hydrocarbon and RTN 3-38454 was assigned to the release. The detection of 2-methylnaphthalene, a semi-volatile organic compound (SVOC) related to fuel oil,
MCP PHASE I COMPLETION STATEMENT, TIER II CLASSIFICATION, AND CONCEPTUAL PHASE II SCOPE OF WORK: 7 CHANNEL CENTER BOSTON, MA

1.3.2.2.1.1 RTN 3-22470
This utility corridor site covers portions of Midway Street, A Street, Binford Street, and Channel Point Avenue. It includes the entire width of Channel Center Street. A Utility-Related Abatement Measure (URAM) was conducted by A Street Properties III, LLC to manage urban fill encountered during installation of private utilities beneath the streets and parking lots within and adjacent to the Channel Center redevelopment site. Results of the chemical soil testing indicated that levels of PAHs, lead, and chloroform exceeded their applicable RCS-1 Reportable Concentrations. Due to the presence of contaminants at levels exceeding the applicable RCS-1 Reportable Concentrations, MassDEP was verbally notified of the URAM on 13 January 2003. The Site was subsequently assigned RTN 3-22470 and utility excavations began in late January 2003. A URAM Transmittal Form and RNF were submitted to DEP on 21 January 2003. The URAM Completion Report for the Site was submitted to MassDEP on 19 May 2004. URAM activities included deep excavations conducted in Medallion Avenue adjacent to 35 Channel Center and 25 Channel Center for the placement of concrete utility vaults, the removal of four abandoned USTs that were encountered within the boundaries of the utility corridor and in Channel
Center Street, soil sampling from the limits of excavations, groundwater sampling, and identifying and managing of urban fill soils.
MCP PHASE I COMPLETION STATEMENT, TIER II CLASSIFICATION, AND CONCEPTUAL PHASE II SCOPE OF WORK: 7 CHANNEL CENTER BOSTON, MA

1.3.2.2.1.2 RTN 3-14748
On 22 January 1997, approximately 20 gallons of No. 2 fuel oil were sprayed onto the roadway and into two catch basins during filling operations conducted at 50 Midway Street (now known as 5 Channel Center) by Supreme Fuel Co. The location of the release was located at the entrance of 5 Channel Center, located adjacent to the subject property. This release triggered a 2-hour reporting condition and MassDEP was notified. MassDEP assigned the release RTN 3-14748. Cyn Environmental applied absorbent material to the impacted asphalt surfaces and disposed of the impacted material off-site. A vacuum truck was utilized to skim fuel oil from the surface of a minimal volume of standing water contained within the catch basin. Impacted sediment from the catch basin was removed and a high-pressure water jet was used to clean the catch basin. Following all activities, a visual inspection of the asphalt surfaces indicated that they were clean and free of fuel oil, and that they contained no large cracks or voids which would have allowed fuel oil to migrate to subsurface media. A Class A-1 RAO was submitted for this release in March 1997. Based on the Class A-1 Regulatory closure achieved, this release is not anticipated to adversely affect the Site.
MCP PHASE I COMPLETION STATEMENT, TIER II CLASSIFICATION, AND CONCEPTUAL PHASE II SCOPE OF WORK: 7 CHANNEL CENTER BOSTON, MA

1.3.2.2.1.3 RTN 3-23180 - 5 Channel Center UST Removal
The building at 50 to 52 Midway Street (now known as 5 Channel Center Street adjacent to the Site to the southwest) was formerly heated by No. 2 fuel oil stored in an UST located at the Channel Center Street (formerly Midway Street) side of the building adjacent to the property boundary with the current Site. The tank was encountered during utility work in Channel Center Street and was removed in September 2003. Photoionization detector (PID) readings taken during the UST removal indicated levels above 100 parts per million by volume (ppmv); accordingly, Haley & Aldrich, Inc. (Haley & Aldrich) provided 72-hour notice orally to MassDEP on 16 September 2003, and MassDEP assigned RTN 3-23180 to the release and provided verbal approval to remove the UST and conduct an assessment-only Immediate Response Action (IRA). Soil samples indicated that levels of compounds remained in the sidewalls and in the bottom of the excavation at levels exceeding RCS-1 Reportable Concentrations. Groundwater samples indicated concentrations of EPH carbon ranges and analytes and VPH carbon ranges at levels exceeding RCGW-2Reportable Concentrations. An IRA Completion Report dated 13 November 2003 was submitted to the MassDEP. A Class A-2 RAO Statement was submitted for RTN 3-23180 in September 2006. The source of the release was identified as a 2,500-gallon No. 2 heating oil UST located within Channel Center Street, located adjacent to a foundation wall that remains. The RAO states that based on the data collected in 2006, petroleum constituents did not appear to extend beyond the vertical and horizontal limits of the former tank grave and the 2003 excavation although this release may have extended on to the 7 Channel Center property.
1.3.2.2.1.4 RTN 3-27506 Channel Center Properties
This site is located adjacent (across Channel Center Street) and west of the Site and is now occupied by a 10-story office building at One Channel Center and a park and other Channel Center buildings (10 through 50). During a soil precharacterization program in 2007 and 2008, soil samples were collected and found certain SVOCs, naphthalene, lead and TPH in soil exceeded the applicable MCP RCS-1 Reportable Concentrations. Groundwater sampling indicated total and dissolved lead above RCGW-2 groundwater standard at one monitoring well. The presence of these contaminants is attributed to the presence of urban fill. MassDEP was notified and assigned the release RTN 3-27506 in February 2008. A Release Abatement Measure (RAM) Plan was submitted was submitted on 31 March 2008. RAM activities consisted of management of contaminated soil related to site improvements, removal of two existing USTs, one above-ground storage tank (AST), and one previously unknown UST encountered during site excavation activities, and selective remedial excavation to remove contaminated soil. A condition of “No Significant Risk” was achieved for current and future site use. The site achieved regulatory closure via a Class A-2 RAO, submitted to MassDEP on 27 July 2010. Based on the regulatory closure achieved, this release is not anticipated to adversely affect the Site.
1.3.2.2.1.5 RTNs 3-1918 and 3-11987 – USPS Properties
On 8 January 1988, the U.S. Postal Service (USPS) received a Notice of Responsibility (NOR) from the MassDEP for a release/threat of release of gasoline detected during a soil excavation for a sprinkler line. The MassDEP assigned RTN 3-1918 to the release. Between 1988 and 1993, several incidents were reported to the MassDEP under RTN 3-1918 including two significant incidents. One incident involved the 1990 detection of petroleum impacted soil and light non-aqueous phase liquid (LNAPL) in the northeast corner of the Vehicle Maintenance Facility (VMF) property. This area was being excavated to install two USTs: one 20,000-gallon diesel UST and one 15,000-gallon gasoline UST. A second incident involved the 1991 discovery of gasoline impact to soil during the removal of two 5,000 gasoline USTs located in the southwest corner of the former VMF building. Subsequently in December 1994, the USPS notified the MassDEP of the presence of dense nonaqueous phase liquid (DNAPL) in a monitoring well. On 22 December 1994, the MassDEP issued a Release Notification and Notice of Potential Responsibility to the USPS and assigned RTN 3-11987. An assessment-type IRA was performed. An IRA Completion Report was submitted in December 1996. A LSP Evaluation Opinion, Tier Classification Submittal, and Phase I Initial Site Investigation (Phase I) Report were prepared and submitted to the MassDEP on December 21, 1995. Given that site conditions related to RTN 3-11987 are similar and within the boundaries of site RTN 3-1918, site RTN 3-11987 was linked to site RTN 3-1918. A Phase III Remedial Action Plan (RAP) was prepared to select a remedial action alternative for the site. Based on the Phase III evaluation, a remedial alternative consisting of an AUL with groundwater monitoring was selected as the most feasible remedial alternative to satisfy the remedial objectives established for this site. It was determined that this alternative would lead to a Permanent Solution (Class A-3 RAO). A Phase IV Remedy Implementation Plan (RIP) Report was submitted to MassDEP on 11 December 1998. This plan included two activities: complete an AUL to limit soil exposure and conduct several rounds of groundwater monitoring to confirm that oil and/or hazardous material (OHM) in soil is not causing OHM concentrations in groundwater to increase. The Phase IV Final Inspection and Completion Report, submitted in March 2004, documented the completion of groundwater monitoring activities. This report concluded that there were no statistically significant increasing trends of any of the site-related OHM in any of the monitoring wells. In June 2009 a Class A-3 RAO Statement and AUL were implemented at the site. The risk assessment concluded that a condition of No Significant Risk had been achieved for health, public welfare, the environment, and safety. An AUL was implemented to maintain the condition of No Significant Risk. Based on the regulatory closure of the release, this site is not anticipated to adversely affect the Site.
1.3.3 Oil and/or Hazardous Material Use and Storage History
Currently, OHM is not being used at the Site. Based on historical records and prior site assessments t here is a 3,600-gallon UST located below the ground floor slab approximately as shown on the attached Figure 2. The UST is reportedly not located in a vault and its condition is unknown. It is planned to remove the UST following building demolition, however access to the UST is currently hindered by the poor structural condition of the existing building. In the interim, the UST is planned to be pumped out prior to demolition. The area north of First Street in South Boston was originally a mud flat known as South Boston Flats. A large segment of the South Boston Flats was filled beginning in the mid-1830s through about 1870. The source of the fill is believed to have been granular material taken from nearby hills, dredged silt, and clay from the Fort Point Channel, building rubble, and coal ash. Fill was observed to contain debris such as brick, concrete, glass, wood, ceramic, ash, cinders, and foam fragments. Historical activities on the Property included industrial facilities using coal and maintaining coal storage areas. A manufactured gas facility operated on the 50 to 54 Sobin Park property, north of the Site. MassDEP
RTN 3-50205, Phase I Initial Site Investigation and Tier Classification, North of Automated Materials Handling Center, One Gillette Park, South Boston, Massachusetts, May 2025

The IRA conducted to assess the extent of the NAPL condition included a TarGOST investigation to evaluate areas between the ZX Building and the AMHC for the presence of contamination consistent with coal tar. The TarGOST investigation included four locations within the Site that is the subject of this Phase I ISI. Contamination in these locations was identified as consistent with fuel oil, and not coal tar. A discussion of the TarGOST investigations within the Site and the results of the investigation are in Section 4.5. Potential petroleum-related contaminant sources are unknown but are likely associated with historical operations pre-dating Gillette’s ownership and the placement of fill during development of the property. The low levels of other contaminants in the shallow fill are likely associated with the fill MassDEP
RTN 3-50205, Phase I Initial Site Investigation and Tier Classification, North of Automated Materials Handling Center, One Gillette Park, South Boston, Massachusetts

"Surface water at the Site appears to be collected in catch basins connected to storm drain system and discharged to Fort Point Channel. Based on the Site topography, surface water runoff appears to flow towards the north and west. Fort Point Channel is located approximately 650 feet northwest and Boston Harbor is located approximately 4,000 feet northeast of the Site."
"The Site was filled over a tidal flat, and the ground surface is nearly flat over a wide area surrounding the Site. The Site is located approximately midway between the Fort Point Channel to the northwest and the railroad bed to the southeast. The railroad bed is depressed about 5 feet below Site grade. Therefore, we would expect the ground water surface to be essentially flat at the Site. However, flow may occur either toward the Fort Point Channel or toward the railroad bed. The direction and rate of flow can be expected to be low but to vary depending on the season, rainfall, tidal stage in the Fort Point Channel, sump pumps in buildings, paving or lack of paving, and the effects of buried utilities and other underground structures, such as buried sea walls. One set of ground water elevation was taken at the Site in February 1994. Ground water depths in MW507, MW508, and MW509 ranged from 3.05 to 4.05 feet below ground surface. The ground water elevations are summarized in Table 2. Based on the one set of ground water elevations, there is a local gradient in an easterly direction toward A Street. Thus it appears that the local ground water flow may be affected by drainage toward buried utilities in A Street, possibly other buried structures or sump pumps, and/or by the paved or unpaved areas nearby, since the gradient would be considerably flatter if such local effects were not present. However, this data is inconclusive and data on ground water levels from a wider area around the Site and over a longer time period are needed to adequately judge the extent to which the ground water flow direction and rate fluctuates over a full year."
Gillette is serviced by the public water and sewer systems operated by the Boston Water and Sewer Commission (BWSC). Potable water is supplied by the Massachusetts Water Resources Authority (MWRA) and the BWSC sewer lines ultimately discharge into the MWRA treatment system.
The chlorinated VOCs, trichlorethylene (TCE), cis-1,2-dichloroethylene, and tetrachloroethylene were detected at maximum concentrations of 130,000, 160,000, and 22,000 fig/kg (ppb), respectively

3.1.1 1950s-PresenT. 64-70 Sobin Park Road is owned by Gillette and is currently a paved parking lot. Previous uses from 1984 to the present were as a loading dock and parking lot. According the 1964 Sanborn Map, the property was occupied by a concrete platform, a railroad spur, and a parking area. No other information is available. 72-76 Sobin Park Road is owned by Gillette and is currently a paved parking lot. A three-story warehouse building was located on the property and was demolished in January 1994. The 1990 Sanborn Map indicates that the building was occupied by a printer. The 1950 and 1964 Sanborn maps showed a chemical warehouse on this lot. The Inspectional Services Department has a record of a 1950 permit issued to the Sobin Chemical Company that lists its occupancy as a warehouse. A 1964 city record listed the building occupancy as offices of the Sobin Chemical Company.
1880s to 1950s. 64-70 Sobin Park Road - The property was vacant according to the 1950 Sanborn Map. The records at the Boston Inspectional Services Department indicate that the 64-70 Sobin Park Road property was vacant in 1930. According to the 1923 Sanborn Map, a harness shed, unlabeled shed, paint shop, and blacksmith and wagon shed were located on the property. The 1899 Sanborn Map also indicates the presence of a harness shed, unlabeled shed and blacksmith and wagon shed. Based on the 1888 Sanborn Map several sheds were located at 64-68 Sobin Park Road and 70 Sobin Park Road was vacant. 72-76 Sobin Park Road - The records at the Boston Inspectional Services Department, along with the 1950 Sanborn Map, indicate a chemical warehouse was located at 72-76 Sobin Park Road. The Sanborn Maps dated 1923, 1919, 1917 and 1899 show a site building occupied by Moore & Wyman, elevator and machine works. No buildings or development of the property are indicated on the 1888 Sanborn Map.
GEI requested a file search by the Boston Fire Department, Fire Prevention Division, to identify past use or storage of oil or hazardous materials [6]. The Boston Fire Department did not report any past or current licenses for underground storage tanks or chemical storage at the Site. The types and quantifies of chemicals stored by Sobin Chemical are unknown. No past or current permits pertaining to wastewater discharge, ground water discharge, Resource Conservation and Recovery Act (RCRA), or National Pollution Discharge Elimination System (NPDES) were located. File searches were performed at the City of Boston Fire Department Fire Marshall's Office and DEP Northeast Regional Office [4,6]. The Gillette facility maintains NPDES Permit No. MA0003832, the discharge point is to Fort Point Channel. Gillette is a RCRA generator MA006605809. Gillette discharges industrial wastewater to sewer system pursuant to MWRA Permit No. 55001985.
PHASE I INITIAL SITE INVESTIGATION 64-76 SOBIN PARK ROAD RTN 3-11312 GILLETTE PARK SOUTH BOSTON, MASSACHUSETTS (JULY 1995)

4.4 Surface Geology
The description of the surficial geology is based on the borings drilled as part of the ISI and other borings previously drilled in the vicinity by GEL.

Miscellaneous Urban Fill. Miscellaneous fill was encountered in the upper 6 to 8 feet. The miscellaneous fill is mostly fine to medium silty sand with widely varying quantities of fine gravel, brick fragments, ash, cinders, and shells. The fill is black in color, which can be attributed to the ash and cinders.
Clayey Fill. Below the fill is a layer of clayey fill. The clayey fill is mostly clayey fines with sand and gravel. The clayey fill layer is gray in color and extends to a depth of approximately 6 to 15 feet.
Organic Deposits Including Peat and Organic Silt. Below the clayey fill is organic silt with peat layers. The organic layer extends from the bottom of the fill to a depth of approximately 35 feet. The organic silt consists of gray slightly plastic silt with fine sand, organic fibers, and shells. The organic silt has zones of brown, odorous, fibrous peat. This deposit is likely to be natural because it contain no foreign material and the structural appearance of the samples collected.
Marine Clay. Below the natural organic deposit is a gray, highly plastic, marine clay [7] (Boston Blue Clay). Although none of the borings for this ISI were drilled deep enough to reach the underlying clay, it is estimated to be encountered at a depth of approximately 31 to 35 feet based on previous subsurface investigations at Gillette property.
Bedrock. None of the borings performed at the Site were deep enough to encounter bedrock. Based on previous subsurface explorations on the Gillette property, the bedrock at the Site is expected to be at a depth of about 70 to 80 feet. The bedrock is Cambridge argillite and is moderately to severely weathered at various locations on the Gillette property [7].
Surface Runoff. Surface water at the Site appears to be collected in catch basins connected to storm drain
system and discharged to Fort Point Channel. Based on the Site topography, surface water runoff appears to flow towards the north and west. Fort Point Channel is located approximately 650 feet northwest and Boston Harbor is located approximately 4,000 feet northeast of the Site.
Ground Water Elevation Survey. The Site was filled over a tidal flat, and the ground surface is nearly flat over a wide area
surrounding the Site. The Site is located approximately midway between the Fort Point Channel to the northwest and the railroad bed to the southeast. The railroad bed is depressed about 5 feet below Site grade. Therefore, we would expect the ground water surface to be essentially flat at the Site. However, flow may occur either toward the Fort Point Channel or toward the railroad bed. The direction and rate of flow can be expected to be low but to vary depending on the season, rainfall, tidal stage in the Fort Point Channel, sump pumps in buildings, paving or lack of paving, and the effects of buried utilities and other underground structures, such as buried sea walls. One set of ground water elevation was taken at the Site in February 1994. Ground water depths in MW507, MW508, and MW509 ranged from 3.05 to 4.05 feet below ground surface. The ground water elevations are summarized in Table 2. Based on the one set of ground water elevations, there is a local gradient in an easterly direction toward A Street. Thus it appears that the local ground water flow may be affected by drainage toward buried utilities in A Street, possibly other buried structures or sump pumps, and/or by the paved or unpaved areas nearby, since the gradient would be considerably flatter if such local effects were not present. However, this data is inconclusive and data on ground water levels from a wider area around the Site and over a longer time period are needed to adequately judge the extent to which the ground water flow direction and rate fluctuates over a full year.

PHASE I INITIAL SITE INVESTIGATION 64-76 SOBIN PARK ROAD RTN 3-11312 GILLETTE PARK SOUTH BOSTON, MASSACHUSETTS (JULY 1995)

MW508 Boring
5ft s2: SILTY SAND WITH GRAVEL (SM); widely graded sand, =20-40% gravel, =10-20% nonplastic silty fines, contains some cinders, brick, coat, ash, and shells; grey to black, FILL. Blows: 4-4, 4-3 (6inch)
10ft S3: no recovery
15ft S5: Top 22": CLAYEY SAND (SC); mostly fine to medium sand, =40-50% nonplastic fines, grey, FILL. Bottom 2": ORGANIC SILT (ML); fibrous; organic odor, grey, SILT. Blows: WOR/12" 4-4
PHASE I INITIAL SITE INVESTIGATION 64-76 SOBIN PARK ROAD RTN 3-11312 GILLETTE PARK SOUTH BOSTON, MASSACHUSETTS (JULY 1995)

Subsurface Conditions. The subsurface conditions (Fig. ES-2) consist of fill soils, peat, and organic silts that overlie a 40-foot-thick clay layer. Below the clay there is glacial till overlying bedrock. The shallow soils above the clay comprise the shallow aquifer. The till and bedrock comprise the deep aquifer. Neither aquifer is used as a source of drinking water. The ground water in the shallow aquifer on the west side of Z Building flows generally toward Fort Point Channel and the gradients are affected by the tides. On the east side of Z Building there is no consistent flow direction. Prior to construction of the Casting Basin, the ground water in the deep aquifer flowed generally north-northwesterly. Since August 1996, the ground water has been pumped from and recharged to the deep aquifer as part of the construction of the CA/T Casting Basin. The project's dewatering operations to maintain the Casting Basin dry and stable, and reinjection operations to maintain the integrity of the Gillette facility buildings, have had an effect on the deep ground water flow patterns at, and adjacent to, the Site.
Site Contamination. 1) Dry Well in the basement of Z Building: Releases of chlorinated solvents (trichlorethene and tetrachloroethene) in Area B, shown in Fig. ES-1, are believed to be the most significant source of contamination at the Site. These releases resulted in soil and ground water contamination in the overburden and bedrock and the presence of pure solvent, which in this case is a Dense Non Aqueous Phase Liquid (DNAPL). Typically, the clay separating the shallow and deep aquifers impedes the flow of water between them. However, the piles that support Z Building allow water and separate phase solvents to leak downward along the periphery of the piles past the clay, into the till and bedrock as illustrated in Fig. ES-2.
2) 168 A Street a -76 Sobin Park Road: Releases of chlorinated solvents to the ground surface in Area A, shown on Fig. ES-1, resulted in soil and ground water contamination that is limited to the overburden above the clay.
3) Historic filling: Historic fill used to create a portion of the property contained debris and coal-ash that is likely a source of some the petroleum hydrocarbon contamination at the Site. The fill was placed over any oil and/or debris that may have accumulated along the bottom of the former Fort Point Channel.
Chlorinated solvent DNAPL exists in the shallow aquifer beneath and east of the Z Building, i.e., on the side where the Materials Handling Center (MHC) is located. The DNAPL sank to the organic silt, silt or clay and flowed downslope on these relatively impervious surfaces until piles were intercepted. DNAPL then migrated down the piles into the deep aquifer. In the bedrock, the DNAPL flows down into the steeply dipping and closely-spaced fractures. DNAPL has not been observed on the west side of Z Building, i.e., on the Fort Point Channel side. Dissolved phase contamination exists in the shallow and deep aquifers and in the clay that separates the aquifers. In the shallow aquifer, dissolved phase contamination (over 100,000 g/l) exists east of Z Building, but has not migrated west of Z Building in significant concentrations. In the deep aquifer, dissolved phase contamination (over 100,000 ug/l) exists on the east and west sides of Z Building. Thus, the dissolved phase contamination flowed down gradient, i.e., northnorthwesterly, and spread out laterally as it passed to the west side of Z Building and into the till and bedrock beneath the clay in Fort Point Channel (Fig. ES-2). Water samples in the sump in the MBTA Red Line tunnel (Figs. ES-1 and ES-2) which is potentially in the path of the plume, showed no chlorinated VOCs. Due to dewatering activities, part of the dissolved phase plume in the deep aquifer is being drawn toward the CA/T Casting Basin dewatering wells. To date only low levels, currently about 6 ug/1 of trichloroethene, have been detected in these pumping wells. Soil contamination typically was identified in the same locations as were the dissolved phase and the DNAPL. The dry well in the basement of Z Building was sealed with concrete and a gasketed and bolted metal cover to eliminate it as a potential pathway for solvent vapor to enter the indoor air. The concentrations in air in Z Building basement are negligible.
PHASE I INITIAL SITE INVESTIGATION 64-76 SOBIN PARK ROAD RTN 3-11312 GILLETTE PARK SOUTH BOSTON, MASSACHUSETTS (JULY 1995)

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Gillette South Boston Manufacturing Center Chapter 91 License Application; FORT POINT Neighb. Assoc. MARCH 31, 2020

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1 November 1999 http://www.erm.com Reference: 251.46 Mr. Duane Wanty, P.C., LSP The Gillette Company Corporate Environmental Affairs Prudential Tower, Building Floor 46 Boston, MA 02119-8004

ERM RE: Tracer Study of Groundwater Flow in Bedrock Aquifer The Gillette Company Facility South Boston, MA Dear Duane: Environmental Resources Management (ERM) is pleased to submit this letter report summarizing the results of a groundwater tracer study completed during August 1999 at the Gillette blade manufacturing facility in South Boston, Massachusetts (Figure 1). BACKGROUND Trichloroethene (TCE) has been detected in shallow bedrock wells MW801B and MW813B (Figure 1). Currently, ERM is preparing to implement an in-situ bioremediation pilot study for the bedrock aquifer in the vicinity of wells MW801 and MW813. Successful design and completion of the pilot study are largely dependent on our understanding of hydraulic properties of the bedrock aquifer (i.e., the ability to effectively deliver substrate, nutrients and microorganisms to areas of impact).
On 12 August 1999, GeoSearch Inc. of Sterling, MA advanced the MW901B borehole to a total depth of 130 feet below ground surface (15 feet into bedrock). Re-drilling was necessary after earlier efforts at redeveloping MW901B were unsuccessful due to the accumulation of silt within bedrock fractures. A step-drawdown test conducted on 17 August 1999 determined the optimal well yield between 5 and 6 gallons per minute. ERM evaluated the dynamics of the bedrock aquifer through a 15 hour tracer study between wells MW901B and MW813B. Following is a summary of results. o Results show strong connection over 11.2 feet of distance, with 50% breakthrough occurring 2.3 hours after tracer injection. Mass recovery of tracer was less than 30% for both tracers, due to radial flow convergence and resulting flowpath mixing/dilution at the pumping well. o Effective porosity for bedrock was calculated at 0.005. o Hydraulic conductivity for the bedrock aquifer was calculated at 0.219 ft/day. o The natural groundwater velocity between MW801B and MW813B is 0.42 ft/day given a 0.0097 ft/ft head gradient. a VOC and hydraulic head data collected during the study suggest that the majority of flowpaths arriving at MW813B originate southeast of the pumping well. These observations coupled with the stable salinity values suggest that fractures in the upper 15 to 20 feet of bedrock are reasonably interconnected immediately west of Z Building

BEOREMEDIEATION PELOT TEST PLAN SOUTH BOSTON FACILITY BOSTON, MASSACHUSETTS Project No. BR003 1 January 2001 Prepared for: The Gillette Company Prudential Tower, Building Floor 46 Boston, Massachusetts 02119-8004

The subsurface conditions (Fig. ES-2) consist of fill soils, peat, and organic silts that overlie a 40-foot-thick clay layer. Below the clay there is glacial till overlying bedrock. The shallow soils above the clay comprise the shallow aquifer. The till and bedrock comprise the deep aquifer. Neither aquifer is used as a source of drinking water. The ground water in the shallow aquifer on the west side of Z Building flows generally toward Fort Point Channel and the gradients are affected by the tides. On the east side of Z Building there is no consistent flow direction. Prior to construction of the Casting Basin, the ground water in the deep aquifer flowed generally north-northwesterly. Since August 1996, the ground water has been pumped from and recharged to the deep aquifer as part of the construction of the CA/T Casting Basin. The project's dewatering operations to maintain the Casting Basin dry and stable, and reinjection operations to maintain the integrity of the Gillette facility buildings, have had an effect on the deep ground water flow patterns at, and adjacent to, the Site.
Dry Well in the basement of ZBuilding: Releases of chlorinated solvents (trichlorethene and tetrachloroethene) in Area B, shown in Fig. ES-1, are believed to be the most significant source of contamination at the Site. These releases resulted in soil and ground water contamination in the overburden and bedrock and the presence of pure solvent, which in this case is a Dense Non Aqueous Phase Liquid (DNAPL). Typically, the clay separating the shallow and deep aquifers impedes the flow of water between them. However, the piles that support Z Building allow water and separate phase solvents to leak downward along the periphery of the piles past the clay, into the till and bedrock as illustrated in Fig. ES-2. The approximate extent of chlorinated solvent contamination in the shallow and deep aquifers resulting from this release is illustrated in Fig. ES-1
168 A Street a -76 Sobin Park Road: Releases of chlorinated solvents to the ground surface in Area A, shown on Fig. ES-1, resulted in soil and ground water contamination that is limited to the overburden above the clay
Historic filling: Historic fill used to create a portion of the property contained debris and coal-ash that is likely a source of some the petroleum hydrocarbon contamination at the Site. The fill was placed over any oil and/or debris that may have accumulated along the bottom of the former Fort Point Channel.
Underground Storage Tanks (USTs): Releases of petroleum hydrocarbons resulted primarily in soil contamination that was limited to the overburden above the clay. The extent of migration from these releases appears to be limited.
Chlorinated solvent DNAPL exists in the shallow aquifer beneath and east of the Z Building, i.e., on the side where the Materials Handling Center (MHC) is located. The DNAPL sank to the organic silt, silt or clay and flowed downslope on these relatively impervious surfaces until piles were intercepted. DNAPL then migrated down the piles into the deep aquifer. In the bedrock, the DNAPL flows down into the steeply dipping and closely-spaced fractures. DNAPL hasnot been observed on the west side of Z Building, i.e., on the Fort Point Channel side. Dissolved phase contamination exists in the shallow and deep aquifers and in the clay that separates the aquifers. In the shallow aquifer, dissolved phase contamination (over 100,000 g/l) exists east of Z Building, but has not migrated west of Z Building in significant concentrations. In the deep aquifer, dissolved phase contamination (over 100,000 .g/l) exists on the east and west sides of Z Building. Thus, the dissolved phase contamination flowed down gradient, i.e., northnorthwesterly, and spread out laterally as it passed to the west side of Z Building and into the till and bedrock beneath the clay in Fort Point Channel (Fig. ES-2).
Water samples in the sump in the MBTA Red Line tunnel (Figs. ES-1 and ES-2) which is potentially in the path of the plume, showed no chlorinated VOCs. Due to dewatering activities, part of the dissolved phase plume in the deep aquifer is being drawn toward the CA/T Casting Basin dewatering wells. To date only low levels, currently about 6 ug/l of trichloroethene, have been detected in these pumping wells. Soil contamination typically was identified in the same locations as were the dissolved phase and the DNAPL. The dry well in the basement of Z Building was sealed with concrete and a gasketed and bolted metal cover to eliminate it as a potential pathway for solvent vapor to enter the indoor air. The concentrations in air in Z Building basement are negligible
The Site was first identified in 1994 when chlorinated volatile organic compounds (VOCs) were encountered on a property at 168 A Street (House of Bianchi) as part of Gillette's environmental due diligence investigation for acquisition of the property. During the due diligence investigation VOCs were also found on an adjacent property owned by Gillette at 64-76 Sobin Park Road. Gillette notified the Massachusetts Department of Environmental Protection (DEP) of a release of oil and hazardous materials (OHM) and was assigned RTN 3-11312 on July 14, 1994. The adjacent property owner was assigned Release Tracking Number 3-11418 on August 4, 1994. Phase I Limited Site Investigation Reports were submitted to DEP for the two sites on July 14, 1995 [1] and August 8, 1995 [2], respectively. Both Sites were classified Tier II. Gillette purchased the adjacent property in the fall of 1995 and combined the Sites in June 1996 into one disposal site called the Sobin Park South Site and retained RTN 3-11312. The Sobin Park South Site has been expanded to include a portion of a second Gillette South Boston Manufacturing Center disposal site, "West of Z Building,C(RTN 3-4365) w3-iith extends from the west side of Z Building to Dorchester Avenue and Fort Point Channel on the west and the Boston Wharf property on the , north. The West of Z Building Site was first listed as a disposal site by DEP on March 30, 1993 and was classified as Tier II by GEI on April 11, 1996 [3]. The primary contaminants for the West of Z Building Site are petroleum hydrocarbons. The portion of the Westof Z Building site that has not been included in the Sobin Park. South Site has been renamed "North of Z Building" -a. 2) rid' MCP response actions will be continued as RTN 3-4365.
Gillette planned construction of a new warehouse, the Materials Handling Center (MHC), on the east side of Z Building. In the spring of 1996, GEI performed soil borings to collect geotechnical information for foundation design. A second area of VOC contaminated soil was found. GEI initiated the Phase II Comprehensive Site Investigation in June 1996 and installed soil borings and ground water monitoring wells to evaluate the extent of contamination in the vicinity of the proposed warehouse. Dense non aqueous phase liquid (DNAPL) was encountered in the fill, silt, clay and bedrock monitoring wells (700-series) installed immediately east of Z Building. The DEP was notified on June 28, 1996 and the release was assigned RTN 3-13952. DEP approved an Immediate Response Action (IRA) for additional assessment and the installation of recovery wells [4]. Two recovery wells were installed, one within the footprint of the proposed MHC.
The MHD, as part of the CA/T project, is currently constructing the 1-90 Channel Crossing across the northerly portion of the Gillette property. This crossing includes a tunnel under the Fort Point Channel and Gillette property north of Z Building. For this purpose, a deep excavation, referred to as the Casting Basin, has been constructed north of Z Building, as shown in Fig. 2. Construction of the Casting Basin required excavation to a depth of 55 ft below the ground surface and included the removal of all overburden soils and a 1.2 million-gallon Underground Storage Tank (UST). A ground water dewatering and recharging system has been installed by the MHD to relieve the ground water pressure in the bedrock. Ten bedrock dewatering wells are located around the perimeter of the Casting Basin. This pressure relief system is-needed to maintain the stability of the bottom of the Casting Basin during construction. Dewatering the bedrock immediately below the Casting Basin also dewaters the rock beyond the limits of the excavation, causing the overlying soft soils to settle and possibly damage buildings and utilities founded in these soils. To reduce the effects of the dewatering on the Gillette buildings, water is recharged into the bedrock by means of twelve ground water recharge wells located along the south side of the Casting Basin. The dewatering and recharge system will be shut down by the MHD upon completion of construction in the Casting Basin.
VOLUME I: TEXT PHASE II COMPREHENSIVE SITE ASSESSMENT -7-SOBIN PARK SOUTH SITE ONE GILLETTE PARK DEP SITE NUMBER 3-11312 SOUTH BOSTON, MASSACHUSETTS Submitted to: Gillette Manufacturing (USA), Inc. South Boston, Massachusetts

In the 1950s, Gillette purchased adjacent American Sugar Company property and in 1962 constructed the Z Building. Blade manufacturing was then located in the Z Building. Through the 1970s and 1980s, Gillette purchased the properties east of the Z Building to A Street including Lindenmeyr Paper (currently M Building), Blue Hills Spring Water, Sobin Chemical, Montgomery Elevator, H&H Construction, Transit America, House of Bianchi, and the Silverman properties. The buildings on all of these purchased properties, except the Lindenmeyr Building have been demolished. In 1995, Gillette constructed the ZX Building which is connected to the east side of Z Building. In 1996, Gillette built the MHC, which also is connected to the east side of Z Building.
In 1905, Gillette relocated from Atlantic Avenue in Boston to its present Site on West First Street in South Boston. Gillette originally occupied A, B, C, and D Buildings. The blade and razor production, Research and Development (R&D) laboratories, shops, warehousing, and offices were originally located in these buildings. Gillette expanded in the 1920s when E, F, G, and K Buildings were added. The Powerhouse was built in 1970 [14]. This area is known as One Gillette Park.
Chlorinated solvents were used in the Z Building from 1962 until 1991, when chlorinated solvents were eliminated from the manufacturing process. A solvent recovery system and two aboveground storage tanks (ASTs) were located in the eastern portion of the Z Building basement (Fig. 5). In 1992, the solvent recovery system and ASTs were decommissioned and removed. An 18-inch by 18-inch dry well with the bottom open in fill beneath the floor slab was constructed during the early 1970s in the immediate vicinity of the solvent storage tanks. The dry well is believed to have been the principal historic entry point for spills of chlorinated VOC contamination into the subsurface. Air testing within and in the vicinity of the dry well confirmed the dry well as a potential migration pathway. In December 1997, Gillette submitted a RAM Plan to the DEP to permanently seal the dry well.
Chlorinated solvents were first used starting in the mid-1950s at Gillette for cleaning purposes in the machine shops. In 1958 TCE use was introduced into the manufacturing process to clean the blades. Blade washing was initially located on the fourth floor in F Building (Fig. 5). In 1962, blade manufacturing was relocated to the Treatment Room on the main floor of the Z Building shown on Fig. 5. Between 1962 and 1974, TCE was used in the blade washing process in Z Building. TCE was replaced by PCE between 1974 and 1980. In 1980 TCE was reinstated as the cleaning solvent until 1991. At that time, all chlorinated solvents were eliminated from blade washing and they were replaced by an aqueous blade washing process.
The concrete floor of the solvent storage and processing area was penetrated by four floor drains that are believed to have been connected to the sanitary sewer and ultimately reached publicly owned treatment works (POTW). In the early 1970s, an 18-inch by 18-inch dry well was constructed within the area. The bottom of the dry well was open to the underlying fill. A float operated sump pump in the dry well is believed to have pumped liquid from the dry well to the sanitary sewer. During the period from the early 1970s through 1991, it is likely that hundreds or thousands of gallons of chlorinated solvents were discharged to the ground from the solvent storage and process still area
Historically fuel oil has been stored at the Gillette facility for heating. A 1.2-million-gallon UST was located north of the Z Building in the right of way taken by the MHD, Fig. 2. This UST had been used by the American Sugar Company prior to Gillette's purchase of the property. The UST was removed by the MHD as part of the CA/T tunnel construction. Two abandoned USTs (RTN 3-12353 and RTN 3-12767) were encountered during construction of the CWS pipeline and were emptied, cleaned, and removed at that time. An UST near the former ballfield (RTN 3-15548) also was removed. Currently, Gillette uses fuel oils, lubricating oils, and sharpening oils at various locations throughout the facility. Fuel oil for the facility is stored in the two 150,000-gallon USTs within the fuel oil storage vault that was constructed in 1995. The location of the fuel oil storage vault is shown on Fig. 4.
VOLUME I: TEXT PHASE II COMPREHENSIVE SITE ASSESSMENT -7-SOBIN PARK SOUTH SITE ONE GILLETTE PARK DEP SITE NUMBER 3-11312 SOUTH BOSTON, MASSACHUSETTS Submitted to: Gillette Manufacturing (USA), Inc. South Boston, Massachusetts

Deep Bedrock several water-yielding zones have been SI I identified at depths of up to 300 ft bgs 9B, and MW811lB that are screened in shallow bedrock. The bioremediation study will be conducted in shallow bedrock due to the higher concentrations of TCE and cis-1,2dichloroethene (cDCE) detected therein and relatively active groundwater flow regime Ucompared to the overlying till and the underlying, less fractured bedrock. The test area subsurface is divided into two.groundwater zones. A shallow unconfined groundwater zone exists in the fill and organic deposit layers and a deep semi-confined groundwater zone is located in the glacial till layer and shallow bedrock. A nearly continuous I confining layer of marine clay (Boston Blue Clay) that is approximately 34 feet thick in the PTA separates these two zones. IBedrock is composed of Cambridge Argillite, which boring data indicate is fine grained, and very thinly bedded, and is characterized by alternating dark and light grey beds of siltand clay-sized particles. Regionally the rock is slightly folded with moderated dipping bedding at angles from approximately 30 to 60 degrees towards the northwest. Typically, the upper 5 to 10 feet of bedrock is fractured (jointed) and moderately to severely weathered by glacial effects. A few till seams or clay filled joints were encountered in the cores obtained i from the Site. The degree of fracturing, as reflected by the increasing Rock Quality Designation (RQD) values, generally decreased with depth. In the test area, heavy fracturing I was observed in the first 20 ft of bedrock.
BIOREMEDIEATION PELOT TEST PLAN SOUTH BOSTON FACILITY BOSTON, MASSACHUSETTS Prepared by GEOSYNTEC CONSULTANTS 532 Great Road Acton, Massachusetts 01720 Project No. BR003 1 January 2001

The complete dechlorination of TCE in anaerobic systems requires the concerted efforts of a number of different groups of anaerobic bacteria including methanogens (methane- I producers), acetogens (acetate-producers), sulphate-reducers and dehalorespirers (specific anaerobic microorganisms that mediate certain dechlorination reactions). While sulphatereducers and methanogens appear to possess the ability to mediate the initial steps of dechlorination of PCE and TCE to cDCE, specific dehalorespiring microorganisms appear to Sbe required to mediate dechlorination of cDCE to VC and ethene. To date, a number of distinct types of dehalorespiring bacteria have been identified, including Dehalospirillium multivorans (Scholz-Muramatsu et al., 1995), Dehalobacter restrictus (Schumacher and Holliger, 1996) and Dehalococcoides ethenogenes (Maymo-Gatell et al., 1997). Unfortunately, these dehalorespiring microorganisms do not appear to be present at all sites. As a result, the dechlorination process for PCE and TCE stalls at cDCE at many sites. Several natural and non-pathogenic microbial consortia have been isolated that are capable of mediating complete dechlorination of TCE to ethene. One such culture, referred to as the Pinellas culture, has been isolated by GE Corporate Research & Development from a Department of Energy facility in Pinellas, Florida. GeoSyntec, working with the University of Toronto, has isolated a similar microbial consortium (referred to as KB-1) capable of stimulating rapid dechlorination of TCE to ethene at sites where appropriate in-situ microorganisms do not exist. These cultures are similar, and contain the known dehalorespiring bacteria Dehalococcoides ethenogenes (Maymo-Gatell et al., 1997) and several other common, non-pathogenic, anaerobic bacteria as methanogens and acetogens. These cultures have not been genetically engineered or modified in any way. As part of the Phase IV Remedy Implementation Plan (RIP), a bench scale treatability study was performed to assess the potential for enhancing the biodegradation of TCE, PCE and DCE by amending groundwater with additional carbon source and augmenting it with bacteria. The treatability study used groundwater and solids (bedrock fragments and soil particles) from the site, and included the testing of 16 separate microcosms (9 bedrock, 5 till, and 2 with both till and bedrock). The study was performed over a 16-week period, although several microcosms were monitored for a longer period extending to 27 weeks. A complete description of the treatability study is included as Appendix 13 to the RIP (ERM, 1999). The results of the study showed that: " Native microbes, found in the till and bedrock at the Site, are able to partially biodegrade TCE under site conditions, but complete dechlorination in a timely manner requires manipulation of the microcosm. o The addition of substrate such as lactate and soybean oil led to the dechlorination of TCE to cDCE. Further dechlorination (to ethene) was supported in unaugmented till microcosms, but not in the unaugmented bedrock microcosms. Addition of molasses did not support dechlorination. o The addition of substrate and augmentation with Pinellas dechlorinating enrichment culture led to complete dechlorination of TCE in till and bedrock microcosms. At the end of the 27-week study period, some VC was still present in the bedrock microcosms, which had higher initial concentrations of TCE. Ethene was produced in these microcosms beginning during week 4 of the study The overall conclusion from this study is that TCE-degrading microorganisms could be present in the till, but do not appear to be present in the bedrock at sufficient concentrations to be effective. Furthermore, microorganisms that currently exist in the till exhibit a limited potential for complete TCE biodegradation without augmentation or enhancement. Thus, to increase biodegradation in the bedrock, microorganisms need to either migrate from the till by creating biologically favorable conditions in the bedrock through nutrient addition or be introduced directly (i.e., bioaugmentation).
BIOREMEDIEATION PELOT TEST PLAN SOUTH BOSTON FACILITY BOSTON, MASSACHUSETTS Prepared by GEOSYNTEC CONSULTANTS 532 Great Road Acton, Massachusetts 01720 Project No. BR003 1 January 2001

4.4 Site Geology and Stratigraphy The Site geology is described in Appendix I. In summary, the following strata were encountered during this and previous subsurface investigations at and near the Site, starting at the ground surface:

Fill - A layer of miscellaneous fill with a thickness ranging from 7 to 39 ft was encountered in every boring. The fill layer contains varying amounts of clay silt, sand, gravel, coal, ash, shells, wood pieces, brick, concrete, glass, and other debris. The fill layer is predominantly black in color; but ranges from green/brown to gray to black. Measured permeabilities in the fill range from 0.014 to 11 feet/day (ft/d) (Table C1).
Peat and Organic Silt - A discontinuous layer of peat and a layer of organic silt with a total thickness ranging from 4.5 to 23.5 ft was encountered below the fill layer in most of the borings. The thickest peat and organic silt layer was encountered in the area of MW804 and MW802. Based on visual descriptions, the peat and organic silt layer consists of varying amounts of organic and inorganic silt, fine sand, and 20 to 70 percent brown fibrous peat. The color of the organic silt and peat layer ranges from brown to gray to black. Based on measurements in these layers at other sites in Boston along the proposed Central Artery, the permeability of the peat and organic silt may range from 3 ft/d to 0.003 ft/d [27]. Due to compression of the peat and organic silt by the fill for over 30 years in all locations on the site, the in-situ permeabilities of this stratum are expected to be at the low end of the above range.
Silt - A layer of slightly-plastic, sandy silt with a thickness ranging from 11 to 265_ft-was encountered in some of the borings. Based on visual observations, the silt layer consists of approximately equal amounts of fine sand and gray-green silt with wood and shell fragments. The color of the silt layer ranges from black to gray/green. Based on measurements in this stratum at other sites in Boston along the proposed Central Artery [27], the permeability of the silt ranges from 3 ft/d to 0.03 ft/d.
Lean Clay - A layer of lean clay with a thickness ranging from 18 to 70 ft was encountered below the silt layer. A plan of the interpolated elevation contours for the top of the clay is shown in Fig. 8. This plan was based on borings carried out over the period from 1912 to the present. Depth to top of the lean clay layer ranges from 18 to 39 ft. The top of clay beneath the Fort Point Channel corresponds approximately to the deepest point under the Channel. Based on visual observations, the lean clay layer consists of silty clay with up to 20 percent fine to very fine sand. The clay has moderate to high plasticity, usually increasing with depth. In most borings the top five ft were observed to be slightly yellowish-brown, which indicates that it may have been desiccated. Based on measurements made in connection with the design of the CA/T Project [27], the horizontal permeability ranges from 0.003 to 0.00003 ft/d. The vertical permeability can be expected to be 2 to 5 times lower. The clay under Z Building is penetrated from top to bottom by piles spaced 20 ft apart near the dry well and MW801. These piles are installed such that partially-sand-filled openings were left between the corrugated steel casing and the adjacent soil. For this reason, one can expect leakage between the shallow and deep aquifers through these pathways.
Till - A layer of glacial till with a thickness ranging from 0 to 36 ft was encountered below the lean clay layer. The depth to top of the till layer ranges from 53 to 103 ft. The till layer consists primarily of clayey to silty, widely-graded sand and gravel. This more cohesive till is known to contain pockets or layers of more granular, i.e., more permeable soil, such as was found at MW811. The till layer is generally absent east of Z Building in the area of the MHC, where clay directly overlies the bedrock. Its thickness increases to the west, as shown in Fig. 10. Data obtained along the Central Artery alignment by GEI [27] indicate that till containing plastic fines, such as under Z Building, has a permeability ranging from 0.3 to 0.003 ft/d. The data in Table Cl show the results of one test in MW813T which gave a permeability of 1.6 ft/d.
Bedrock - Bedrock consisting of Cambridge Argillite exists below the lean clay or till layers. The depth to bedrock ranges from 58 to 113 ft. The upper 5 to 10 ft of bedrock is highly weathered in most locations. Below the top 5 to 10 ft, the bedrock is medium-hard to hard, light-gray, very fine grained, and slightly to moderately weathered. It contains very close to close bedding joints (one inch to > 14 in.) with dips that vary from horizontal to vertical. A second joint set dipping about 60 degrees from the vertical crosses the bedding. The spacing of these joints is typically 2 to 5 ft. and many were calcite healed. At one location near South Station, the joint dip is 50 degrees to the NNW [29]. The permeability of the bedrock was measured at 7 locations on the Sobin Park South Site and at four-ocations to the north of the Site in and around tfClstingBasin. The results are presented in Appendix C, Table C1.

The flow of water through bedrock is best represented by a large scale pumping test or by the higher values obtained from a series of borehole tests, particularly for estimating transport rates of dissolved contaminants. For the ground water simulation model a permeability of 0.8 ft/d was used. This value lies at the 65 percefitilCofiethborehole permeability test results in Table Cl, which is consistent with GEI's past experience in making comparisons between borehole and pump test data at the same location. Data for the elevation of top of bedrock in the vicinity were obtained from borings that were drilled on the Gillette property in South Boston for construction of buildings and for environmental investigations, as well as borings made in the vicinity for the CA/T project. Fig. 9 shows the contours of the top of bedrock. The top of bedrock slopes from a depth of about 60 ft on the east side of Z Building to about 110 ft on the west side of Z Building. A bedrock trough exists near the location where the easterly boundary of Fort Point Channel bends to the west. As will be seen later, it is at this location where dissolved VOCs are likely traveling in the bedrock ground water beneath the Channel. An east-west trending longitudinal cross section through the bedrock trough is shown in Fig. 10 at equal horizontal and vertical scales. Between the dry well and MW801 the top of bedrock dips downward at about 10 degrees below the horizontal. The bottom of the trough remains approximately horizontal for several hundred ft. Further to the west, the top of bedrock slopes slightly downward.

There are two primary ground water aquifers at the Site: * The shallow aquifer in the fill, peat, organic silt, and silt above the clay; and * The deep aquifer in the till and bedrock below the clay. The shallow aquifer extends from the ground surface to the top of the clay, which is about 18 to 40 ft below ground surface at the Site. The top of the deep aquifer lies between 50 and 110 ft below ground surface.

Ground water flow directions in the peat, organic silts and silts that originally existed at the site varied with the tides, since these were mud flats of South Boston. The net gradient was from the high ground at the east to the low at what is now Fort Point Channel. At present, the flow direction in the entire shallow aquifer, including the fill, is locally influenced by granite seawalls, many utilities-liid historic foundations, and on the west side of Z Building, by-tidal changes in the Fort Point Channel. The fill and the original soils above the clay are penetrated by several buried seawalls that are composed of granite blocks. The seawalls were encountered during construction of the new cooling water system along the west side of Z Building, during construction of the ZX Building and the southerly extension of the M Building on the east side of Z Building, and during excavation of the Casting Basin on the north side of Z Building. Approximate locations of the seawalls are shown in Reference 12. During construction of the new cooling water system west of Z Building, and during excavation for the new buried fuel oil vault between Z Building and the ballfield, large zones were found where the fill was almost totally made up of bricks, with little soil in the voids. This zone was at the inlet that was filled by Gillette in the early 1960s (Fig. 4). As part of the installation of the new cooling water system on the west and north sides of Z Building, a clean sand backfill was placed around the pipes. This zone forms a longitudinal permeable zone from the bottom of the paved surface to a depth of 12 ft to 14 ft. Due to the seawalls, the zones of relatively clean brick fill, the sand backfill for the new cooling water piping, and the variable nature of the fill, the ground water levels and flow velocities in the shallow aquifer are highly variable. They are also affected by the tides in Fort Point Channel, particularly on the west side of Z Building. For example, during construction of the new cooling water system and fuel oil vault, the water levels in the open, partially sheeted excavation, rose and fell with the tide unless the pumps (2- 6 in. and 1- 8 in.) were operated continuously. Nevertheless, part of the fill consists of soils that impedes the effects of tides, and monitoring wells in such locations are less affected or not affected. On the east side of Z Building the shallow aquifer ground water levels are only slightly or not affected by tides. However they likely are affected by the presence of the permeable granite seawalls and by utility pipes (electrical, water, sewer, storm drains, and steam) in \ the former Sobin Park Road and A Street. A current ground water contour map in the shallow aquifer at mid-tide is shown in Fig. 12. The data for this plot is listed in Appendix C. Fig. 12 shows gradients toward the Fort Point Channel on the West of Z Building. It also shows a low spot near MW806 on the east side of Z Building. The gradient in the shallow aquifer on the west side of Z Building fluctuates with the tide level. At low tide, the gradient is toward the Channel, and at high tide it is in the opposite direction. The net gradient is downward toward the Fort Point Channel as shown in Fig. 12.

Interpolated historic ground water elevation contours prior to the start of pumping are shown on Fig. 13 for conditions approximating the low tide condition. The data for these plots are shown provided in Appendix C. The contours show that prior to pumping and recharging for the Casting Basin, the ground water flowed north-northwesterly with a gradient of about 0.01 in the vicinity of MW813A. Fig. 13 shows that the ground water elevations for the low tide condition tend to lie below mean sea level and even below mean low water (i.e., below El. 94). Data recorded by GEI [27], GZA [30], and Haley & Aldrich [31] all show that the ground water levels in the deep aquifer lie somewhat below mean low water at some locations along the Central Artery, at the interchange between the Massachusetts Turnpike and 1-93, and in South Boston. The cause of such ground water lowering below mean sea level is not known. Some possible causes are: * Unknown pumping from the bedrock. The pumping could be nearby or along the fault that parallels the west side of Fort Point Channel [29]. It is not known whether the fault is relatively pervious or not; * Drainage into sewers or storm drains that may exist nearby in the bedrock; and * Density effects of brackish water in bedrock.
Review of these possibilities gave the following results: * The Massachusetts Water Resources Authority (MWRA) and the Boston Water and Sewer Commission (BWSC) have no storm drains or sewers in the till or deep bedrock in the vicinity of the site. The nearest deep sewer is 3,500 ft to the south. * The Massachusetts Turnpike Authority has no facility that pumps water out of the till or bedrock. * The MBTA has a sump in the Red Line Tunnel which drains waters that infiltrate the Tunnel and Broadway and South Stations. At South Station, approximately 50 ft below ground, which at that location is in glacial till, there is a basement sump with a flow that, based on visual observation, may be about 20 to 40 gpm [32]. The source of the water may be ground water and/or surface water. * Based on conductivity measurements of the water from bedrock wells, the concentration of salt in the water is so small that the density of this brackish water would not significantly influence the ground water levels. Thus, the only possible known causes of the ground water lowering in the westerly direction from the site, prior to 1996, are the MBTA sump in the Red Line Tunnel and sub-drainage at South Station. Water from the sump in the Red Line Tunnel has been tested and found to contain no chIrintafd-VOCs. In addition, the flow into that sump may be primarily surface water from the adjacent stations. Based on pre-CA/T ground water contours compiled for the CA/T by Shannon and Wilson [33], it is unlikely that there is a connection between South Station and the zone west of the Site where the ground water levels are below mean low water. To date, no specific cause of the ground water lowering below mean low water, under ambient conditions prior to the CA/T pumping, has been found... prior to Casting Basin construction, the seepage velocity in the till may have ranged up to about 20 ft/yr and in the bedrock from 10 to 150 ft/yr. The ground water contours in Figs. l'3 and-14 show the changes in direction of flow and gradients caused by the dewatering and recharge system that currently is in place.
Vertically, the chlorinated VOC contamination from this release has migrated through the fill material into the underlying peat and silt layers. The vertical migration is a result of gravity drainage from the surface into the saturated zone. Once in the saturated zone, after dissolution of the DNAPL into the ground water advection and dispersion of the dissolved phase plume also become significant transport mechanisms. Concentrations indicative of a former DNAPL are present (e.g., 760,000 Mg/1 total VOCs at MW425). This explains the presence of contaminants at greater depths in the silt overlying the clay (e.g., 14,900 pg/l total VOCs in water and 258,000 pg/kg total VOCs in soil at MW506 up to 30 ft depth). The lateral extent of significant contamination in the silt appears to be limited as evidenced by surrounding borings and wells in the silt. The top of clay in Fig. 8 indicates a southwesterly slope in this area, yet well MW803S has significantly lower concentrations. There are no known avenues of transport downward through the clay layer in this vicinity. The decreasing concentrations at depth indicate that the solvents have reached residual saturation and are no longer flowing by gravity. Further downward migration of this release is limited by the presence of the underlying clay layer.
The lateral movement of the release is primarily due to advection and dispersion of the aqueous phase contamination. Volatilization and then migration as a vapor phase in the thin unsaturated zone is also a likely, though lesser, transport mechanism. At the lateral fringes of contamination, concentrations decrease dramatically. This is due primarily to dilution (as a result of dispersion), sorption onto soil, and biodegradation. The latter is evidenced by the presence of dichloroethene and vinyl chloride. Based on field evidence (e.g., soil and ground water quality data and ground water contours), it does not appear that this release is continuing to expand. Towards the west, this plume may commingle with the basement of Z Building releases described below. There are no likely impacts on surface water, sediment or food chain pathways from these Area A releases

The releases in the basement of Z Building consisted primarily of PCE and TCE. Over time, these constituents have migrated laterally and vertically. The contamination resulting from the basement of Z Building releases now encompasses an area of about 300,000 sf. Measurements show that the depth of contamination is over 140 ft below ground surface
DNAPL has been observed near the basement of Z Building dry well (e.g., MW701, MW704, MW706, REC-1, REC-2). The primary component of DNAPL flow in the fill and silt materials is downward. At the upper surface of the organic silt or clay (Fig. 10), due to their lower permeabilities, the DNAPL can flow laterally down slope. At this site, the foundation of Z Building is constructed on piles designed as illustrated in Fig. 19. The piles terminate either in the till or bedrock and they fully penetrate the approximately 50-foot-thick clay layer. The piles create a pathway for DNAPL to continue its preferred downward migration by gravity. Once in bedrock, DNAPL flows vertically down steeply dipping and closely spaced fractures until residual saturation is reached. The total depth of contamination at the Site is not known, but may reach a few hundred feet.
The lateral movement of the release is primarily due to gravity drainage of the DNAPL and advection and dispersion of the dissolved contamination. * At some point(s), the DNAPL encounters a pathway allowing it to again follow its preferred downward migration (as discussed above under Vertical Migration). As the DNAPL flows past the piles, lateral transport into coarser seams within the clay is possible. Once in the bedrock the DNAPL follows fracture pathways, which at this Site are closely spaced and dip steeply (Appendix I). Due to their close spacing, the fractures probably provide only a small lateral component of gravity flow. Throughout the saturated zone, DNAPL continuously dissolves into the ground water
allowing the dissolved phase contamination to migrate laterally by advection and dispersion. * Volatilization and then migration as a vapor phase in the thin unsaturated zone is a significantly less important transport mechanism. S At the lateral fringes of contamination, concentrations decrease dramatically. This is due primarily to dilution, as a result of dispersion, sorption onto soil, and biodegradation, which is evidenced by the presence of dichloroethenes and vinyl chloride. Based on soil and ground water quality data and ground water contours, it does not appear that this release is continuing to expand to the north, east or south. However, additional migration of the dissolved phase plume may be continuing in the westerly direction. * The farthest downgradient ground water sampling point most recently shows concentrations of chlorinated solvents of 120,000 pg/1 TCE at MW813B in bedrock. Data collected since January 1998 from MW813B suggest a decreasing trend in concentration, but the data are not yet sufficient to determine whether this trend will continue. * An investigation of possible receptors on the west side of the Fort Point Channel indicates that the MWRA, the BWSC, the MBTA, and the Massachusetts Turnpike Authority have no facilities in the area that might serve as receptors. The Boston Building Department has no record of any pumping in that vicinity. Therefore it appears that the only likely receptor is the sump in the MBTA Tunnel. In July 1998, the water samples from that sump contained no chlorinated solvents. * The composition of the chlorinated solvent plume varies slightly across the Site. In particular, near the source of the basement of Z Building releases (e.g., MW702D, MW704D, REC-2) and also at MW808, the PCE percentage is approximately 5 to 10 percent of the total VOCs. However, northwest from the source (e.g., MW801B, MW813B), the PCE percentage is less than 1 percent of the total VOCs. This change is likely due to the faster rate of biodegradation of PCE than of TCE, although the explanation may lie in the relative volumes of the two solvents that were released.
VOLUME I: TEXT PHASE II COMPREHENSIVE SITE ASSESSMENT -7-SOBIN PARK SOUTH SITE ONE GILLETTE PARK DEP SITE NUMBER 3-11312 SOUTH BOSTON, MASSACHUSETTS Submitted to: Gillette Manufacturing (USA), Inc. South Boston, Massachusetts

CHANNELSIDE

The Channelside property is an approximately 6.5-acre surface parking lot located at 244-284 A Street in South Boston, Massachusetts. The property is bounded by the Fort Point Channel to the west, Binford Street and Gillette Manufacturing Facilities to the south; an undeveloped parcel and Necco Street to the north; and A Street to the east. The central portion of the property is over the Fort Point Tunnel (FPT) and associated casting basin (remnant buried slurry wall support of excavation [SOE] system)
constructed in the 1990s. Surface grades across the site are relatively level, ranging from approximately elevation (El.) 14 to El. 16. 1 The general site location and adjacent site conditions are included in Figure 1 and Figure 2.
The Site was originally part of the South Boston tidal flats and contained an approximately 100-ft wide by 600-ft long shipping channel/dock area which extended in a west-to-east direction approximately perpendicular to the Fort Point Channel. The shipping channel and surrounding site areas were filled as part of land and road development and building activities undertaken by the Boston Wharf Company during the mid-19th century. Slips and former wharf seawalls were constructed with wood pile and timber cribbing foundations and bases that supported stacked (and sometimes mortared) granite block gravity walls oftentimes backfilled along the land side with oyster shells to reduce lateral loads and promote drainage; remnants of the former slip and boundary seawalls are present and buried below the existing parking surface.Various warehouses and other commercial and light industrial buildings (likely wood pile supported) occupied select areas across the site until about 1980. Notable historical site uses include coal storage and shipping circa 1899, bulk oil storage circa 1923-1930, a tin shop circa 1923-1945, an oil and tractor shed circa 1945-1955, an auto repair shop circa 1945-1955, and a filling station from approximately 1930 to 1980.Work for the FPT project included excavation of almost half of the site area for a casting basin to construct the immersed tube tunnel sections of the portion of I-90 EB/EB crossing the Fort Point Channel between 1999 to 2002. The casting basin was constructed with tied-back slurry walls, which subsequently served as the temporary SOE for the construction of the FPT’s cut-and-cover tunnel sections that extend under the site. Following construction of the FPT, the site was used by the CA/T project for laydown and staging between 2002 and 2004. The present-day parking lot was constructed around 2005 and has been in operation since that time.

RTN 3-4365 was assigned by MassDEP in 1993 based on the identification of petroleum-impacted soil apparently caused by leaking historical underground storage tanks (USTs) on the Gillette property. Contaminated soil near the subject property was reportedly over-excavated during construction of the Gillette circulating water system (CWS) intake structure in 1995. The on-site portion of RTN 3-4365 and the abutting Gillette CWS intake structure were closed with a partial RAO in 1999.

RTN 3-11312 is administratively linked to RTN 3-4365 but pertains to the release of chlorinated volatile organic compounds (CVOCs) from a former drywell in the Gillette manufacturing complex. Investigations performed on the Gillette property identified CVOCs in the deep groundwater aquifer in the glacial till and bedrock on that property. RTN 3-11312 has not achieved regulatory closure but has remained in Phase V Remedy Operation Status (ROS) managed by Gillette and overseen by MassDEP. Previous environmental reports filed with MassDEP indicate a portion of the southwest corner of the Project Site also overlaps with the boundaries of RTN 3-11312. However, the closest boundary of the RTN 3-11312 CVOCs plume is reportedly approximately 650 ft southwest of the Project Site. Furthermore, available analytical testing has not indicated that soil or groundwater at the site is
impacted by constituents of concern from that release. Therefore, RTN 3-11312 is not considered to be associated with proposed RAM activities.

RTN 3-12233 is associated with petroleum-impacted soil previously reported under RTN 3-4365 that was encountered during construction of the Gillette CWS structure that abuts the site to the west. RTN 3-12233 was triggered in 1995 due to the inadvertent discharge of oil to the Fort Point Channel during temporary construction dewatering operations. The RTN achieved regulatory closure in 1995.

RTN 3-16020 is associated with the historical CA/T Fort Point Tunnel casting basin and is related to the inadvertent release of diesel fuel and hydraulic fluid to the Fort Point Channel during construction activities in 2001. The exact location of the RTN 3-16020 is not known but is believed to be within the former casting basin. Following mitigation and cleanup activities, RTN 3-16020 achieved MCP closure with the filing of a Response Action Outcome (RAO) Statement with MassDEP in 2002.

A generalized description of the subsurface units encountered is provided below:

Miscellaneous Fill was encountered at each exploration location. The Fill soils are generally described as light brown to black, gray to dark gray, loose to dense, poorly graded SAND with various amounts of silt, clay, and gravel. Varying amounts of anthropogenic materials were encountered throughout the Fill including ash, cinders, organic materials (peat and silt), shells, wood, brick, concrete, and other debris. The Fill thickness varies and appears to be greatest towards the southern site limits, in the general area of an historic shipping channel (see Section 1.3). Within these areas the Fill thickness ranged between approximately 18 and 32 ft; elsewhere on the site, the Fill thickness ranged from approximately 6 to 15 ft. At borings GT-8 and GT-9 – located with the MassDOT FPT easement – Fill material consisting of medium dense to dense SAND or GRAVEL with sand was encountered from ground surface down to the presumed bottom of tunnel elevation (i.e., about 51 to 53 ft below existing site grades). The material encountered is presumed structural fill placed during the CA/T project.
Cohesive Fill and Organic Deposits were encountered at each test boring location and varied in thickness from about 1 to 17 ft. In general, these materials were described as very soft to stiff ORGANIC SOIL with variable quantities of sand, shells, and peat. At locations where PEAT was encountered, the thickness ranged from about 1 to 4 ft.
Marine Deposits (Clay) were encountered at each boring; the depth to the top of this stratum ranged from about 17 to 34 ft below ground surface (bgs), corresponding to El. -1 to El. -19. In general, the Marine Clay (known locally as the Boston Blue Clay) is described as yellow brown to olive gray, very soft to hard CLAY with varying amounts of sand and gravel. In general, the stiffness of the Marine Clay deposits is found to decrease with depth into the deposit.
Glacial Deposits were encountered beneath the Marine Deposits at depths ranging from 44 to 51 ft bgs, corresponding to approximately El. -28 to El. -36. The stratum is described as a Glaciomarine Deposits consisting of a lean CLAY with trace sand, gravel, and silt; and Glacial Till Deposits consisting of a dense sandy SILT with varying amounts of gravel, clay, and cobbles.
Bedrock underlying the site consists of ARGILLITE and was encountered at depths ranging from about 52 to 71 ft bgs, corresponding to about El. -36 to El. -57, and generally increasing in depth from north to south across the project site.

Based on measurements obtained from observation wells installed in the near surface fill soils and piezometers installed in the deep glacial deposits and bedrock, groundwater elevation at the site ranges from about El. 6 to El. 10 BCB in the near surface fill soils; and about El. 3 to El. 7 in the deep glacial deposits and bedrock.

REPORT ON RELEASE ABATEMENT MEASURE (RAM) PLAN CHANNELSIDE 244-284 A STREET SOUTH BOSTON, MASSACHUSETTS RELEASE TRACKING NUMBER (RTN) 3-36456 by Haley & Aldrich, Inc. Boston, Massachusetts for Massachusetts Department of Environmental Protection Wilmington, Massachusetts File No. 131781-012 January 2022

GT-11 TOP OF BEDROCK 73.0 FT 43 S13 74.0 ML Very dense purple gray SILT with gravel (ML), mps 10. 75 in., 97 18 75.5 decomposed bedrock fabric, moist. Sample consists of completely 75- 85 weathered, decomposed ARGILLITE. Rock crumbles easily with light finger pressure. 100ft S14 84.0 GM , Very dense purple gray silt GRAVEL (GM), mps 1.0 in. Decomposed bedrock structure, moist, sample consists of 85- completely weathered, highly fractured, ARGILLITE. Crumbles easily with light finger pressure. Note: Less than 50 PSI bit weight. Pressure required to advance roller bit in highly weathered rock from 73.0-84.0 ft. Note: Increased roller bit resistance indicates harder rock zone from -89.0-94.0 ft. 200 PSI bit weight pressure required to advance bit. Note: Drill action indicates softer, highly weathered rock 94.0-119.0 90- ft. Less than 50 PSI bit weight pressure required to advance it through vert soft, highly weathered rock. -BEDROCK- -BEDROCK- 92 S15 114.0ft ML Very dense purple gray gravelly SILT (GM), mps 0.75 in., 114.6/ decomposed bedrock structure, moist. Sample consists of severely weathered ARGILLITE. Rock crumbles easily with light finger pressure. Advanced boreholes with roller bit to 119.0 ft. Drill action indicates very soft, highly weathered rock, similar to above. -103.0 119.0 \. -BEDROCK- I BOTTOM OF EXPLORATION 119.0 FT Note: Borehole tremie grouted to 19.0 ft upon completion.

GT-10 (OW/PZ) Hard olive gray lean CLAY (CL) interbedded with very thin parting partings of gray SILT (ML), trace gravel, mps 0.50 in., aminated, no odor, moist, trace decomposed argillite in spoon tip TOP OF BEDROCK 71.0 FT 71.0 74.0 GM Very dense light gray silty GRAVEL (GM), mps 1.5 in., distinct 75.2 rock fabric, moist, sample consists of weathered ARGILLITE, 75- 50/2" crumbles easily with light finger pressure 80 rock fabric, moist, sample consists of highly weathered, fractured ARGILLITE, crumbles easily with light finger pressure 84.0 GM Similar to above -BEDROCK Note: Spun NW casing to 86.5 ft. SEE CORE BORING REPORT FOR ROCK DETAILS 86.5 60 100 Slight Medium hard, slightly, weathered, gray, aphanitic ARGILLITE. Bedding very thin, 91.5 48* 80* moderately dipping. Joints dipping at moderate to high angles, very close to close, smooth to rough, planar, discolored to decomposed, tight to open. 91.5 Slight Similar to above, except bedding dipping at low to moderate angles, with occasional horizontal joints, occasional open, decomposed joints. 96.5 High Very soft to medium hard, highly weathered, gray aphanitic ARGILLITE. Bedding and joints indistinct due to poor rock quality. Rock very brittle, breaks easily with light impact. -BEDROCK- NR 101.5 0 0 High to No Recovery Lost core assumed highly to completely weathered Note: Drove split spoon 106.5-107.2 ft. Blows 38-75/2". Recovered 7 in. Very dense gray SILT, trace gravel, with residual, bedrock fabric. Sample consists of completely weathered ARGILLITE. Advanced borehole with rollerbit to 109 ft. Drill action indic High Soft to medium hard highly weathered gray aphanitic ARGILLITE. Bedding and joints indistinct due to poor rock quality. 114.0 BOTTOM OF EXPLORATION 114.0 FT 0 Note: Borehole grated to 60.0 ft upon completion, : Vibrating wire piezometer installed at 55.0 ft. Ground water observation well at 15.0ft. *Indicates RQD figured for medium hard bedrock

REPORT ON RELEASE ABATEMENT MEASURE (RAM) PLAN CHANNELSIDE 244-284 A STREET SOUTH BOSTON, MASSACHUSETTS RELEASE TRACKING NUMBER (RTN) 3-36456 by Haley & Aldrich, Inc. Boston, Massachusetts for Massachusetts Department of Environmental Protection Wilmington, Massachusetts File No. 131781-012 January 2022

Reportedly, the South Station rail terminal was constructed on land created (reclaimed) through a series of land filling or "wharfing out" events, the process of constructing wharves outward from the shore and later filling the slips between them (Krieger, A; Cobb, D.; and Turner, A; 1999). These land filling events, which reclaimed much of the site and vicinity, began in Boston in approximately 1630 and continued through at least 1916. The expansion of Shawmut Peninsula into the present configuration of Boston is depicted on Figure 4. The majority of the site area appears to have been filled circa 1795 to expand the original land as dock space into the South Cove. The area of the site was further filled between approximately 1833 and 1852 and again around 1880, transforming the South Cove into the Fort Point Channel. Reportedly much of the material used to fill these areas originated from fill obtained from the leveling of hills in Boston and surrounding area, street sweepings, harbor and waterway channel dredging, coal ash, and ship ballast (Krieger, A; Cobb, D.; and Turner, A; 1999 and Whitehill, W. M., 1973).
Based on the soil characteristics observed during the drilling of the soil borings and the findings of the soil matrix evaluation conducted by STL, the site is underlain primarily by 3.5 to 5 feet of ballast, which in turn, is underlain by approximately 5 to 10 feet of fill (fill layer). Based on drilling observations and the samples collected during drilling, at least 17 feet of fill was encountered in some of the borings. This fill layer ranges from a dark brown fine to coarse sand with varying amounts of gravel and debris (primarily brick, wood, coal ash, pieces of partially burned coal, and asphalt) to silt intermixed with sand, gravel and wood. This fill layer is underlain at most locations by an olive gray clayey silt (organic silt) layer to a depth of at least 21 feet below grade. Marine shells were observed in the organic silt layer. A cross-section of the stratigraphy in the release area based on the characterization of the soil samples collected during the drilling, is provided as Figure 6
As previously discussed, the release in October 1995 impacted the ballast on and adjacent to Tracks 7 and 8. Limited cleanup of the release occurred at the site in October 1995. Observations made by the cleanup contractor indicated that additional petroleum impacted soil was encountered that may be unrelated to the October 1995 motor oil release. This additional impacted soil was encountered at a depth of approximately 3.5 to 4 feet below grade. As discussed previously, this area of the site has undergone significant filling events, the most recent occurring in the late 1980's/early 1990's in which approximately 3 to 4 feet of fill material was placed over former rail beds at the terminal. Soil samples collected from the fill material at the site contained coal ash and partially burned coal. Note that PAHs are commonly found in coal ash and partially burned coal. Therefore, the PAHs detected in soil samples collected from the fill material at the site are likely attributable to this coal ash and partially burned coal. As a result, PAHis resulting from the presence of these fill materials are considered background (310 CMR 40.0006)
Track 7, Two South Station, Phase II (2000).

Based upon geologic information provided in the EDR Radius report, soil types in the area of the vacant Property are classified as silty loam. Soil characterization completed during subsurface investigations and monitoring well installation activities conducted as part of IRA activities indicated that, in general, soils located above 15 feet bgs consist of well graded sands and silts, and also contain varying amounts of anthropogenic fill, including coal, ash, concrete and brick debris. The top of the very dense and dry fine to medium sand and silt (till) was observed at approximately 14 to 28 feet bgs (below the groundwater table). Bedrock was not encountered during subsurface investigations and impacted soil and groundwater appears to be limited to the top of the till material.
The area of impacted surficial soil identified at the vacant Property is limited to the anthropogenic fill used for raising the elevation at the Property during historical use. Because the vacant Property is unpaved, surficial soil is subject to wind, surface water erosion, and/or physical transport. However, the risk of significant migration is low and there are no people living at the vacant Property and trespassing does not appear to occur for extended periods of time. Based upon subsurface characterization activities, the VOC impacts in subsurface soils begin in the saturated zone at approximately 7 feet bgs and terminate at approximately 28 feet bgs at the disposal site. PID measurements quickly decreased when borings were advanced into the dense till at a depth of approximately 17 to 20 feet bgs. Bedrock was not encountered at depth and therefore, is not anticipated to be impacted by the release of chlorinated VOCs and is not a medium of concern.
Measured depths to groundwater in monitoring wells installed during IRA activities ranged between 7 to 9 feet bgs. Based upon slug tests conducted in November 2015 at three monitoring wells located on the vacant Property, hydraulic conductivity values range from less than 0.1 ft/day to 1.01 ft/day. The lowest hydraulic conductivities correlate with dense soil across the screened interval of monitoring wells MW-01 and MW-04 (approximately 4 to 14 ft bgs). The highest hydraulic conductivity is associated with predominantly medium dense, sands, gravels, and silts in the vicinity of the screened interval of monitoring well MW-03 (5 to 20 ft bgs). Based upon the groundwater elevations, local groundwater flow in the general vicinity of the vacant Property was estimated to be to the southeast. Refer to Figure 3 for a copy of the May 2016 approximate groundwater elevation contours and Table 8 for a summary of groundwater elevation data.
Based upon groundwater flow direction data in the vicinity of the vacant Property, groundwater samples from the immediate downgradient monitoring wells (WC-7S and WC-7D) also exceed the GW-2 and GW-3 standards for PCE, TCE, and cDCE. However, groundwater data collected from monitoring wells located approximately 75 to 200 feet downgradient of the vacant Property (opposite side of West Broadway) indicate that while concentrations of these select VOCs are present, they are at concentrations below the applicable MCP standards.
The closest surface water to the vacant Property is the Fort Point Channel, located approximately 2,000 feet to the north-northwest. Based on the disposal site boundary, distance to the channel, the general elevation of the vacant Property and surrounding properties, and the presence of a stormwater collection and piping system located in the roadway, the potential for migration of impacts from the vacant Property to surface water via overland processes is insignificant. It is not anticipated that constituents associated with this release would be detected in surface water located greater than 500 feet from the vacant Property.
On May 11, 2016, MassDEP issued an approval notification to Woodard & Curran to proceed with the in-situ aerobic bioaugmentation program as outlined in the IRA Modification Plan. The bioaugmentation program consisted of using direct push technologies to deliver microbial colonies and amendments to the subsurface in targeted treatment zones within the source area. Between May 18 and May 30, 2016, Woodard & Curran personnel conducted a pre-injection groundwater sampling event (which included the collection and analysis of groundwater samples from seven monitoring wells), marked out 15 intended injection locations (identified as INJ-1 through INJ-15), set transducers in eight monitoring wells within and in proximity to the targeted injection areas, staged two 250-gallon totes, each containing approximately 205 gallons of clean water for the hydration of the microbes prior to the injections, and hydrated the microbes (as well as provide them with approximately 200 pounds of dextrose sugar). Pre-injection groundwater data are summarized on Table 2. On May 30, 2016, the bioaugmentation injections commenced. Injections were completed using a track-mounted hydraulic direct-push Geoprobe drill rig. Injection activities were completed on June 2, 2016. Approximately 410 gallons of microbes, sugar and water was injected into 14 locations, INJ-1 through INJ-14. Approximately 15 gallons of rinsate (fresh water and the microbial solution) generated from washing out the totes was injected in the ground at the 15th and final location, INJ-15. On August 17, 2016, 200 pounds of an oxygen supplement (Permeox Ultra) was injected into 8 locations. The purpose of the oxygen supplement was to increase the dissolved oxygen in the groundwater that was depleted by the microbes that were injected in May/June 2016.
Phase I Initial Site Investigation, Tier Classification, and RTN Linking Report 206-212 West Broadway South Boston, MA RTN: 3-33140 RTN: 3-33172 229286.03 September 2016

On May 30, 2016, Woodard & Curran returned to the vacant Property to add and mix the microbes in one of the totes of water. The microbes were thoroughly mixed into the tote with a clean, dedicated length of PVC piping. The following day, May 31, 2016, Woodard & Curran added approximately 200 pounds of dextrose sugar to the tote prior to injections. Per vendor recommendations, the microbes were hydrated within 24-hours of initiating injections and the sugar was mixed 2 hours prior to injections. A sample of the injection mixture was collected from the tote after sufficient time was given to allow the microbes and sugars to dissolve. The sample, identified as Tote #1, was submitted on ice under chain-of-custody protocol to Test America of Westfield, Massachusetts for analysis of total organic carbon (TOC) via SW846 method 9060A. A sample was also shipped on ice via UPS Overnight to Osprey Biotechnics of Sarasota, Florida for microbial plate count and identification analysis. Unfortunately, the microbial laboratory did not dilute the saturated tote sample enough to get a representative depiction of the colony forming units and the results are presented as greater than laboratory reporting limits. Typically, the tote sample would contain approximately 1 billion colony forming units. As expected, the TOC value was elevated due to the presence of dissolved sugar in the sample. The TOC is useful in evaluating the presence of a “food source” for the microbes to survive and thrive to produce the enzyme necessary to degrade PCE and the associated breakdown products. Analytical laboratory reports are provided in Appendix C. Refer to Table 4 for a summary of groundwater analytical results. On May 30, 2016 at approximately 0900, the bioaugmentation injections commenced. Geosearch completed injections using a track-mounted hydraulic direct-push Geoprobe drill rig. At each injection location, the Geoprobe drive rod was advanced to the prescribed total depth at which point it was retrieve to approximately half of the injection interval (e.g., if the injection was to be completed from 10 to 15 feet bgs, the drive rod would be advanced to 15 feet bgs and retrieved to 12.5 feet bgs). The microbial solution was then injected using a pump as described below. When half of the predetermined injection volume had been added, the drive rod was then retrieved to the top of the injection interval. Injection depths and volumes were predetermined based on historic soil and groundwater sampling results as well as the injection location within the targeted injection zone and its proximity to the 216 West Broadway structure. Refer to Figure 5 for the final injection locations, injection pressures, and injection volumes per location. For each location, the required injection volume was transferred with a Wilden double diaphragm pump into a 35-gallon container equipped with a graduated site glass. The same pump was then used to pump the injection mixture through the Geoprobe drive rod into the ground. During an injection, the site glass was timed for every 5 gallons or 10 gallons injected so an approximate injection flow rate could be determined for each location. Flow rates averaged approximately 3.5 gallons per minute (gpm), with a maximum flow rate of 7.5 gpm at location INJ-14 and a minimum flow rate of 1.0 gpm at INJ-11. Injection points that had higher flow rates were in looser and coarser grained soils whereas the lower flow rates were observed in tighter, finer-grained soils at the vacant Property. Prior to commencing an injection, Woodard & Curran collected depth to groundwater measurements from the groundwater monitoring wells nearest an injection point, these locations were then monitored during an injection for visible upwelling. Subsequently, groundwater depths were collected from the same suite of monitoring wells following an injection to determine the extent and magnitude of mounding (if any). Localized mounding was typically observed and as a result, injections did not occur sequentially (i.e., Injections were staggered across the targeted injection areas so to not exacerbate the groundwater mounding in one a particular area at a given time). Groundwater was noted to be upwelling at WC-1 and WC-2 during injections at INJ-11 and INJ-4 respectively. In these instances, the flow rate was reduced to a siphon (approximately 1.0 – 1.5 gpm) to minimize upwelling. The upwelling and mounding was also recorded by the transducers. The mounding dissipated quickly based upon gauging and transducer data. During injection activities, the basement of 216 West Broadway (nearest the injection locations) was monitored for breakout and odor. During the injection activities, breakout and odors were not observed. At the conclusion of the first day of injections (May 30), Woodard & Curran added the microbes to the second tote. Two-hundred pounds of dextrose sugar was added to the second tote of 205 gallons of water and microbes on June 1, 2016, approximately 2 hours prior to injection. This volume was injected at the remaining locations and injection activities were completed on June 2, 2016. Approximately 410 gallons of microbes, sugar and water was injected into 14 locations, INJ-1 through INJ-14. Approximately 15 gallons of rinsate (fresh water and the microbial solution) generated from washing out the totes was injected in the ground at the 15th and final location, INJ-15. At the conclusion of injections, Geosearch demobilized the drill rig, totes and fencing and Woodard & Curran removed the transducers.
Immediate Response Action Status Report # 2 206-212 W. Broadway South Boston, MA RTN 3-33172 Prepared for: City of Boston Department of Neighborhood Development 229286.03 July 2016

206 W Broadway

Al's Liquor Store basement

Shea's Tavern

Al's Liquor Store basement

Either Al's Liquor Store or Shea's Tavern

Al's Liquor Store basement

2 Alger St

DOWNTOWN WATERFRONT / SEAPORT

Item d. Site Hydrogeological Characteristics
Geologic Setting: Soil Conditions
The subsurface explorations conducted at the Site typically encountered the following soil units, listed
in order of their occurrence below ground surface:

Fill: The fill soils encountered consist primarily of varying amounts of cinders, ash, concrete, brick, wood, and glass fragments. The fill thickness varies from approximately 8 to 15 ft.
Cohesive fill (organic silt and sandy clay): The organic soils encountered consist primarily of soft, dark gray organic silt with varying amounts of clay, sand, shells, and peat. The cohesive fill thickness varies from approximately 13 to 19 ft.
Marine Deposits: The marine deposits (known locally as the Boston Blue Clay) encountered consist of silty fine sand with alternating layers of silt and clay and organic silt. The cohesive fill thickness varies from approximately 83 to 93 ft.
Bedrock: While bedrock was not encountered in subsurface explorations conducted at the Disposal Site, in this area it is mapped to be the Cambridge Argillite described as a gray argillite and minor quartzite; rare sandstone and conglomerate (Goldsmith et al., 1983

Groundwater Conditions Groundwater levels measured in February 2008 indicate that groundwater levels are approximately 7.7 to 8 ft below the ground floor slab of the building and approximately 5 to 6 ft. below existing ground surface outside the building area. The ground surface elevation of the ground surface outside the building ranges from El. 15 at Congress Street to El 14 at the southwest corner of the building, therefore groundwater elevations range from approximately El. 8 to 9. The direction of groundwater flow is to the south, southeast and is likely influenced by the presence of nearby subsurface utilities and tunnel structures. Additionally, regional groundwater flow is likely substantially influenced by the presence of the MBTA Silver Line Transitway, the Central Artery/Tunnel (CA/T) Project, and the Fort Point Channel.

MCP Phase I Initial Site Investigation Report, Tier II Classification Submittal and Phase II Conceptual Scope of Work 381 Congress Street Boston, Massachusetts Release Tracking Number 3-3189

The subject site was originally part of the South Boston tidal flats and was filled in the 1870s. The area was filled with material dredged from Boston Harbor and covered with several feet of sand and gravel at the surface. The property and vicinity were developed with a railroad terminal yard including rail spurs, platforms, and freight warehouses in the 1880s. The historical alignment of Congress Street (currently abutting the site to the north) intersected the north and northeast portions of the site. The rail spurs and railroad buildings were removed from the subject site by the mid-1980s, and the property remained vacant until it was paved for use as a parking lot in the late 1980s. The site was mainly used for parking, but also served as a construction staging area during the Central Artery Tunnel (CA/T) highway construction in the early 1990s. Congress Street has shifted through the site over time and was used as a temporary road during the CA/T project as shown on the attached aerial photographs. Support of the elevated Summer Street also changed over time. A steel viaduct for Summer Street was constructed over the southern portion of the site by 1899. A truss bridge was visible in the 1938 aerial photograph. The 1969 aerial photograph shows the bridge partially demolished around the time of the railyard decommissioning. Summer Street was subsequently re-constructed as a soil embankmentsupported road as shown on the 1978 aerial photograph. Removal of the embankment and construction of the current Summer Street bridge were conducted in conjunction with the CA/T project during the late 1990s-early 2000s

Generally, the subsurface explorations revealed the following geologic units listed in order of occurrence from ground surface downward:

Miscellaneous Fill
- Fill – The Fill consists of medium to very dense historic urban fill consisting of SAND, CLAY, and/or GRAVEL with varying amounts of silt, clay, cinders and clinkers, asphalt, bricks, concrete, glass, metal and shell fragments, and other materials was encountered immediately below the paved parking lot surface. Concrete slabs and rubble fill layers were encountered within the Fill.
- Cohesive Fill – A stratum of soft to very stiff lean CLAY and ORGANIC SOIL was encountered beneath the Fill across the Site at each of the boring locations. This stratum layer is likely the result of historical hydraulic filling of the site, and was described as a heterogeneous mixture of miscellaneous materials (debris, cinders, shells, organic soil, etc.).
Organic Deposits – A thin, soft to stiff Organic Deposits layer consisting of olive-gray to dark brown ORGANIC SOIL, with some peat fibers, was encountered at some explorations, typically 1 to 2 ft thick and as thick as 6.5 ft at HA19-B4/5. Disturbed organic soils were also encountered intermixed within the Cohesive Fill stratum.
Marine Deposits (Sand/Silt) – This stratum was typically described as a medium dense to very dense silty SAND and sandy SILT interbedded with seams of silt and clay. The Marine Sand thickness is generally thicker on the east side of the site and thinner on the west side and thin to not encountered below the Summer Street bridge.
Marine Deposits (Clay) – The Marine Deposits typically consisted of very soft to very stiff lean CLAY interbedded with occasional seams of silt or sand. Medium stiff to stiff clay deposits, referred to as the clay crust, were encountered at the top 5 to 15 ft of the strata.
Glacial Deposits – A variety of Glacial Deposits were encountered below the Marine Clay and above the Bedrock. The deposits vary in thickness and are not present at each deep test boring location.
- Glaciomarine Deposits were encountered at HA19-A8 and HA19-D8 and select CA/T boring locations consisting of very stiff to hard sandy lean CLAY or SILT with gravel and cobbles.
- Glaciolacustrine Deposits were encountered at select CA/T boring locations consisting as dense to very dense SILT or fine SAND with silt and gravel.
- Glacial Till Deposits were encountered at HA-19-A8 and HA19-D8 and select CA/T boring locations consisting dense to very dense SILT, CLAY, SAND or GRAVEL with varying amounts of silt, clay, cobbles. It was occasionally noted as well bonded in-situ.
Bedrock – Two recent borings, HA19-A8 and HA19-D8, and ten CA/T borings were drilled to Bedrock. The top of weathered bedrock slopes toward the south of the site. A weathered bedrock zone was encountered at the top 3 to >31.5 ft and consists of SILT with varying amounts of gravel with a distinct rock fabric from the ARGILLITE or tuffaceous ARGILLITE. The sound bedrock was collected with rock cores and was described as TUFF, ARGILLITE and tuffaceous ARGILLITE. The three rock types observed in the borings are all sedimentary, primarily fine-grained to aphanitic; however, the sediment that formed the rocks was derived from different origins. In general, Tuff was derived from volcanic ash, argillite from a sea environment, and tuffaceous argillite involved volcanic ash settling in a sea environment.

Groundwater levels within the recently installed observation wells HA19-B7(OW) and HA19-D2(OW) were measured during April 2019 and locations are included on Figure 2. Groundwater levels were observed to range from El. 8.8 to El. 13.2. A summary of groundwater measurements is provided below. Refer to Appendix C for observation well installation records.
Table IV: Summary of Groundwater Observation Well Measurements
Well ID Approximate Ground Surface Elevation (BCB, ft) Well Screen Depth Interval (ft) Soil Conditions at Well Screen Date Depth (ft) Elevation (BCB, ft)
HA19-B7 (OW) 19.3 8 to 18 2 ft of sand and ash Fill 8 ft of Cohesive Fill 4/17/2019 9.0 10.3 4/25/2019 6.1 13.2 5/1/2019 6.2 13.1
HA19-D2 (OW) 16.8 7 to 17 3 ft of sand Fill 7 ft of crushed shells with trace organic soils 4/10/2019 8.0 8.8 4/25/2019 8.0 8.8 5/1/2019 8.0 8.8
Groundwater levels vary with season, precipitation, construction activity in the area, below-grade structures, leakage from utilities, and other factors. As a result, groundwater levels observed during and following construction may vary from those observed in the observation wells.

The results of the precharacterization program indicate the presence of VOCs, SVOCs, petroleum hydrocarbons, and metals in soils at levels above the applicable MCP RCS-1 Reportable Concentrations. No evidence of a point source release has been observed, and the soil contaminants are likely attributable to the presence of Fill or reworked natural soil, which is ubiquitous and consistently present in urban areas, and to historic Site use. The Fill typically consists of sand with varying amounts of silt, clinkers, bricks, ash, cinders, wood, concrete, and other debris. Seaport N/P Title Holder LLC first obtained knowledge of the presence of Reportable Concentrations in the soil on 5 June 2019. Accordingly, a BWSC103 Release Notification Form (RNF) for Reportable Concentrations was submitted to MassDEP via eDEP on 27 August 2019, and MassDEP assigned Release Tracking Number (RTN) 3-35801 to this release. Chemical analysis of groundwater collected during Site precharacterization indicated concentrations of compounds below laboratory detection limits or their respective RCGW-2 Reportable Concentrations. Given these results, groundwater is found not to be impacted by the Site and is not considered to be part of the Site.

Release Abatement Measure (RAM) Plan Seaport Square Parcel N/P 391 Congress Street Boston, Massachusetts RTNs 3-14803 and 3-35801 December 2019

Prior to approximately 1873, the site was a tidal flat of Boston Harbor. HISTORY Sea walls were constructed at the site during the period of 1873 through 1877 as part of an agreement to fill and develop the site. The area between the granite block sea walls is understood to have been filled with "clay" dredged from the adjacent tidal flats, Fort Point Channel and Boston Harbor that was covered with three feet of "gravel". Slips and docks were formed by the filling behind the sea walls and by dredging between the sea walls to create deep water to allow for the docking of ships. Wooden platforms extending out from the granite dock walls were constructed to bridge the area between the walls and the deep water within the slips used for docking ships. Three piers identified as Piers 1, 2 and 4 were created on the newly filled land. One slip was located between Piers 1 and 2, and another slip was located between Piers 2 and 4. A third pier, Pier 3, was proposed between Piers 2 and 4, but is understood to have never been constructed. The approximate limits of the former slips are indicated on Figure 2

Railroad spur lines were constructed along the piers in the late 1800's, and the abutting property was used as a railroad switching yard by the New York and New England Railroad. Warehouse buildings were constructed adjacent to the tracks and the docks during the early twentieth century and these were occupied by various tenants through the 1960's. A second phase of filling occurred at the site between 1969 and 1971 when the dock between Pier 1 and Pier 2 and the dock between Pier 2 and Pier 4 were reportedly filled with granular materials including.building debris. It is understood that the specifications for the this site filling excluded the use of "boulders greater than 12 inches in diameter, organic soils, wood, trash, and other deleterious materials." Furthermore, it is understood that the wooden platforms extending outwards from the docks were removed, however, the piles and dock walls are understood to have been covered over during the filling. After about 1960, the current use of the property as a paved parking lot commenced, and aerial photographs dated 1955, 1969 and 1978 indicate the progressive demolition of most of the warehouse buildings that were formerly located on the property.

Underlying the bituminous concrete pavement that typically blankets the project site, the explorations generally encountered a granular fill deposit ranging from about 1.5 to 23 feet in thickness. The granular fill deposit was typically observed to consist of a loose to very dense, brown to black to gray, heterogeneous mixture of silt, sand and gravel containing varying amounts of brick, concrete, wood, ash and cinders. Underlying the granular fill deposit, the boreholes generally encountered a very loose to compact, gray to black, dredged fill deposit which typically consists of silty clay containing a trace to some sand and gravel, a trace of organics, also containing varying amounts of wood, brick, ash and cinders. The dredged fill was observed to vary from 3 to 50.5 feet in thickness across the site. The bottom of the dredged fill deposit was encountered at depths ranging from 21 to 54 feet below the existing ground surface. As a result of the dredging and filling history of the site, the total thickness of fill ranged from 32 to 54.5-feet within the area of the former Pier 1/Pier 2 slip. Outside the former slip, the total thickness of the fill deposits generally ranged from 21 to 27-feet outside the slip. Outside the footprint of the former Pier 1/Pier 2 slip, the granular and/or dredged fill deposits were generally underlain by a natural organic deposit representative of the former tidal flats. The natural organic deposit was observed to range from about 1 to 12.5 feet in thickness and generally consists of a very soft to firm, gray organic silt, containing a trace to some fine sand and a trace of fibrous peat and shells. The fill and/or naturally organic deposits were generally underlain by a marine sand deposit consisting of a loose to dense, gray fine to medium sand and silt. The marine sand deposit was observed to range from 2 to 12.5 feet in thickness. An extensive deposit of marine clay, known locally as Boston Blue Clay, underlies the fill, organic and/or marine sand deposits and extends to depths ranging from about 98 to 129 feet below the existing ground surface, corresponding to about Elevation -81.1 to approximately Elevation -112, respectively. The marine clay generally consists of a very stiff to very soft, gray silty clay with occasional fine sand seams and partings. The thickness of the silty clay deposit decreases moving from west to east across the site from about 46 to 65 feet within the former Pier 1/Pier 2 slip to about 100 to 103 feet thick outside the former slip. At depths ranging from 98 to 129 feet below the existing ground surface the borings encountered dense to very dense glacial soil deposits. The glacial outwash, glaciomarine, and glacial till deposits were generally comprised of sand and gravel with varying amounts of silt, with the glaciomarine deposit also containing a trace to some clay. The glacial deposits were observed to vary from 7 to 17.5 feet in total thickness where they were penetrated.

Directly underlying the glacial deposits the borings encountered a fractured deposit of bedrock known locally as Cambridge argillite. The surface of the bedrock deposit was observed to vary from 136 to 147 feet below the existing ground surface, corresponding to about Elevation -119 to Elevation -131, respectively. The observation wells installed at the site indicate that the groundwater level generally ranges from about Elevation +9.2 to Elevation +10.4. Based upon the soil and groundwater conditions at the site, we consider the groundwater to be "perched" or trapped within the granular fill deposit above the surface of the relatively impervious dredged fill deposit. It is anticipated that future groundwater levels across the site may vary from those reported herein due to factors such as tidal fluctuations, normal seasonal changes, runoff particularly during or following periods of heavy precipitation, and alterations of existing drainage patterns. Groundwater Monitoring Reports are presented in Appendix B

a. Total Metals A total of sixty-three (63) samples of dredged fill material were submitted to the laboratory for chemical analysis for the presence of total RCRA-5. metals. The results indicated concentrations of arsenic, barium, cadmium, mercury, selenium, and silver all well below the applicable RCS-1 Reportable Concentrations in soil as defined in the MCP, 310 CMR 40.0000. Two (2) of the tested samples exhibited the presence of total lead at concentrations of 330 mg/kg and 390 mg/kg which are above the RCS-1 standard of 300 mg/kg. Given the observed presence of ash, coal ash and cinders present in the fill material and the results of the above analysis, the levels of total lead are attributed to the nature of the fill materials and also to the urban character of the site. Therefore, the levels of lead detected in the fill material on the subject site are considered exempt from notification of the DEP in accordance with the Massachusetts Contingency Plan (MCP) at 310 CMR 40.0317 (8) and (9). Samples of the dredged fill material that exhibited total chromium concentrations greater than 30 mg/kg were analyzed for the presence of hexavalent chromium (chromium VI) as discussed in the granular fill material section of this report. The results indicated the presence of chromium VI at concentrations below the laboratory method detection limit which is well below the RCS-1 standard of 30 mg/kg for chromium VI for the samples analyzed. Therefore, the level of total chromium detected in these samples is attributable to the presence of chromium Ill. The detected concentrations were well below the RCS-1 standard of 1,000 mg/kg, and hence are not considered to represent a reportable concentration. Samples of the fill material that exhibited total lead concentrations greater than 100 mg/kg were analyzed for the presence of TCLP (leachable) lead. The results indicated the presence of TCLP lead in the 19 samples analyzed at concentrations ranging from below the laboratory method detection limits up to 2.3 mg/1. analyzed, with the exception of naphthalene detected in boring F-8 sample S16-S18. Naphthalene was detected at 9.2 mg/kg and therefore above the RCS-1 standard of 4 mg/kg. The elevated concentration of naphthalene is directly correlated with elevated concentrations of SVOCs in this sample. The elevated concentrations of SVOCs are attributable to the presence of a significant amount of ash and cinders in the fill material, and therefore, the SVOC considered to be exempt from reporting pursuant to the MCP Section 40.0317. Further, the indicated level of naphthalene for the dredged fill sample S16 to S18 obtained from boring F-8 on Parcel F is below the concentrations reported for the Fan Pier project under RTN 3-19647 for which a Method 3 Risk Characterization and an RAO indicated a level of No Significant Risk.
Fan Pier, Parcel F; RELEASE ABATEMENT MEASURE PLAN FAN PIER --PARCEL F, (RTN) 3-27188 (November 13, 2007).

TEST BORING REPORT, BORING B118, FILE NO. 5556 SHEET NO. 4 OF 5
110 Hard gray coarse to fine sandy SILT, trace gravel (ML-SM) - GLACIAL TILL -
115 Hard gray fine sandy SILT, *(300-1b hammer) little fine gravel (ML-SM) - GLACIAL TILL -
120 Completely to very severely weathered grey aphanitic ARGILLITE *(300.-lb hammer)
125 Very soft very severely to completely weathered, moderately fractured to sound. gray, aphanitic ARGILLITE; close, open, smooth joints.
130 - Soft, moderately severe to severe weathered, extremely fractured to sound, gray, aphanitic ARCILLITE, very close to close, open, smooth joints. (130.8 ft - 130.9 ft clay seam)
134.0 ft Bottom of Exploration
Notes: 1. Observation well installed in completed borehole. Refer to installation report for details. 2. RQD not calculated due to severity of weathering.
Fan Pier, Parcel F; RELEASE ABATEMENT MEASURE PLAN FAN PIER --PARCEL F, (RTN) 3-27188 (November 13, 2007).

TEST BORING REPORT, BORING B103, FILE NO. 5556 SHEET NO. 4 OF 5
130 trace coarse to fine SAND, little silt, sand, gravel
140 Very dense gray coarse to fine sandy GRAVEL, little silt, (bonded in-situ) (GM) - GLACIAL TILL -
145 Very dense gray silty medium to fine SAND, little coarse sand, trace gravel, (very well bonded in-situ) - GLACIAL TILL
150 Cray very severely weathered ARGILLITE. (Hard gray clayey SILT, little gravel
155 No Recovery. Moderately hard to medium, very slightly to slightly weathered, slightly fractured to sound (except extremely fractured from 155.7 to 155.8 ft), gray, aphanitic ARGILLACEOUS SANDSTONE; close. open to tight. steeply dipping (55*- 85), smooth to rough joints; minor shears perpendicular to' bedding from 154.1 to 156.0 ft; very thin high angle (55'- 85*) bedding [NOTE: Presence of former fractures that have been "healed".]
160 Medium, very slightly to slightly weathered, moderately fractured to sound, gray aphanitic ARGILLACEOUS SANDSTONE; close, open to tight, steeply dipping (55 - 85 ), smooth to rough joints; very thin. steeply dipping (55*- 85*) bedding. [NOTE: Presence of former fractures that have "healed".]

Fan Pier, Parcel F; RELEASE ABATEMENT MEASURE PLAN FAN PIER --PARCEL F, (RTN) 3-27188 (November 13, 2007).

BORING HA19-D8.... MARINE DEPOSITS Similar to above, except medium stiff Similar to above, except soft with occasional sand partings Similar to above, except medium stiff with frequent fine sand partings Similar to above, except soft -MARINE DEPOSITS Soft gray lean CLAY (CL), mps < 1 mm, no structure, no odor, wet PP < 0.25 tsf Very soft gray lean CLAY (CL), mps < 1 mm, no structure, no odor, wet -MARINE DEPOSITS Note: Drill action indicates strata change at 99.0 ft. Hard light gray gravelly lean CLAY with sand (CL), mps 1.5 in., no structure, no odor, moist, with cobbles Note: Drilled through BOULDER from ~ 101.0 ft - 103.0 ft. -GLACIOMARINE DEPOSITS Very stiff gray sandy lean CLAY with gravel (CL), mps 1.5 in., no structure, no odor, wet, with cobbles Note: After washing out to 109.0 ft, borehole collapsed. Spun NW casing to 109.0 ft and continued sampling. Very dense gray silty SAND (SM) to sandy SILT with gravel (ML), mps 1.5 in., well bonded in situ, moist -GLACIAL TILLTOP OF DECOMPOSED BEDROCK 112.5 FT Dense light gray SILT with gravel (ML), mps 0.75 in., distinct rock fabric, moist. Sample consists of severely weathered, decomposed tuffaceous ARGILLITE. Rock crumbles easily with light finger pressure. Similar to above, except very dense with distinct high angle bedding. Rock crumbles readily with moderate finger pressure. -DECOMPOSED BEDROCK Similar to above Similar to above, except bedding indistinct Note: Drill action indicates harder bedrock at ~ 130.0 ft. -BEDROCK Very soft to soft, moderately weathered, light gray, aphanitic tuffaceous ARGILLITE. Bedding extremely thin, brecciated, dipping at moderate to high angles. Joints dipping at moderate to high angles, very close to close, smooth, planar, discolored to decomposed, tight to open, with silt infillings and coatings. Note: After coring C1, several inches of gray medium to fine grained SAND observed in top of core barrel, indicating open sand infilled fracture, possibly near the bottom of C1. NW casing spun to 136.0 ft. Similar to above, with bedding frequently indistinct. Medium hard, slightly weathered, light gray, aphanitic tuffaceous ARGILLITE. Bedding extremely thin, brecciated, dipping at high angles. Joints dipping at moderate to high angles, close to widely spaced, smooth, planar, decomposed, tight to open, with silt and clay infillings. -BEDROCKSimilar to above, with no discernible joints Similar to above, except moderately hard, bedding dipping at moderate to high angles. Joints horizontal to moderately dipping, very close to moderately close, smooth to rough, planar, discolored to decomposed, tight to open and occasionally calcite healed, with frequent silt and clay infillings and coatings. Similar to above Similar to above, with no joints Note: Pump shut off, core barrel jammed at 165.0 ft due to pump failure.

BORING HA19-A8
Note: Pushed 3.0 in. diameter undisturbed tube sample from 54.0 ft - 56.0 ft. Very soft gray lean CLAY (CL) with occasional silt partings, mps < 1 mm, no structure, no odor, moist PP 0.25 tsf -MARINE DEPOSITS Note: Pushed 3.0 in. diameter undisturbed tube sample from 64.0 ft - 66.0 ft. Soft gray lean CLAY (CL), mps < 1 mm, no structure, no odor, wet PP < 0.25 tsf -MARINE DEPOSITS Very stiff gray sandy lean CLAY with gravel (CL), mps 1.5 in., no structure, no odor, wet, with cobbles -GLACIOMARINE DEPOSITS Dense light gray sandy SILT with gravel (ML), mps 1.5 in., no structure, no odor, wet, sample consists primarily of decomposed - eroded argillite -GLACIAL TILL Very dense gray sandy SILT with gravel (ML), mps 1.5 in., well bonded in-situ, moist, with cobbles TOP OF DECOMPOSED BEDROCK 122.0 FT Dense purple gray SILT (ML), mps < 1 mm, relict decomposed bedrock structure, moist, sample consists of completely weathered argillite -DECOMPOSED BEDROCK/RESIDUAL SOIL Note: Drill action indicates harder bedrock at ~ 128.0 ft. -BEDROCK Very dense gray poorly graded GRAVEL with silt (GP-GM), mps 1.5 in., distinct rock fabric, dry, sample consists of fractured, weathered argillite SEE CORE BORING REPORT FOR ROCK DETAILS Moderately hard to soft, slightly to moderately weathered, gray aphanitic tuffaceous ARGILLITE. Bedding very thin, irregular, brecciated, dipping at high angles to vertical. Joints dipping at moderate angles to vertical, occasionally low angle to horizontal. Joints very close to moderately close, smooth to rough, planar to undulating, discolored to decomposed, tight to open with frequent silt infillings and coatings. -BEDROCKC2: Similar to above, except moderately hard to medium hard, slightly weathered, bedding less distinct. Joints dipping at moderate angles to horizontal, very close to close, smooth to rough, planar, discolored, tight, open. C2 (137.5 ft - 140.0 ft): Moderately hard, slightly weathered, light gray aphanitic TUFF. Bedding indistinct. Joints similar to above. Similar to above, except slightly to moderately weathered. Joints dipping at moderate to high angles, occasionally low angle to horizontal. Joints very close to close. -BEDROCK Soft to medium hard, slightly to moderately weathered, gray, aphanitic tuffaceous ARGILLITE. Bedding very thin, irregular, dipping at high angles. Joints similar to above. Medium hard, slightly weathered, gray aphanitic tuffaceous ARGILLITE. Bedding very thin, irregular, dipping at moderate to high angles. Joints dipping at low angles to horizontal, occasionally high angles. Joints very close to moderately close, smooth, planar, discolored to decomposed, tight to open, with frequent silt infillings and coatings. -BEDROCK Similar to above, except moderately hard. Bedding less distinct. One open clay infilled joint at ~ 159.5 ft. Similar to above, with very soft highly weathered zone from ~ 164.2 ft - 165.0 ft. Bedding very thin, dipping at high to low angles. Joints dipping at moderate to high angles, very close to moderately close, smooth, planar, discolored to disintegrated, with frequent silt infillings. BOTTOM OF EXPLORATION 165.0 FT Note: Borehole tremie grouted to ground surface at completion. -MARINE DEPOSITSSimilar to above, with seams of silty SAND (SM), and lean CLAY (CL) Medium dense yellow brown sandy SILT (ML), mps < 1 mm, stratified, no odor, wet S16: Medium dense yellow brown silty SAND (SM), mps < 1 mm, no structure, no odor, wet S16A: Very stiff yellow brown to gray lean CLAY (CL), mps < 1 mm, no structure, no odor, wet Similar to above, except stiff, gray Similar to above, except medium stiff, with trace fine sand in frequent partings Similar to above -MARINE DEPOSITSSimilar to above Similar to above Note: Pushed 3.0 in. diameter undisturbed tube sample from 44.0 ft - 46.0 ft. Medium stiff gray lean CLAY (CL) with frequent silt partings, mps < 1 mm, no structure, no odor, moist PP 0.75 tsf

Release Abatement Measure (RAM) Plan Seaport Square Parcel N/P 391 Congress Street Boston, Massachusetts RTNs 3-14803 and 3-35801 December 2019

BORING HA19-E2 | 18ft Black to dark brown ORGANIC SOIL (OL/OH), fibrous top 3.0 - 4.0 in., becoming more gray to dark gray with depth, moderate hydrogen sulfide-like odor, wet -ORGANIC DEPOSITS; 20ft Gray brown (organic) silty SAND (SM), mps 2 mm, no structure, hydrogen sulfide-like odor, wet -ORGANIC DEPOSITS

BORING HA19-D1 | 15FT Dark brown ORGANIC SOIL (OL/OH), mps 0.3 in., no structure, strong hydrogen sulfide-like odor, wet Gray brown (organic) silty SAND (SM), mps 3 mm, no structure, hydrogen sulfide-like odor, wet -ORGANIC DEPOSITS | 17FT Gray well graded SAND (SW), mps 4 mm, no structure, hydrogen sulfide-like odor, wet -MARINE DEPOSITS

BORING HA19-C6 | Note: From ~ 17.8 ft - 18.8 ft black ORGANIC SOIL (fill) with slight petroleum and hydrogen sulfide-like odor, light gray CLAY with sand below | 20ft Dark brown (organic) silty SAND (SM), becoming less organic and silty with depth, slight hydrogen sulfide-like odor, wet -ORGANIC DEPOSITS | 21 ft Gray brown poorly to well graded SAND (SP/SW), mps 0.3 in., coarsening with depth, slight hydrogen sulfide-like odor, wet

Release Abatement Measure (RAM) Plan Seaport Square Parcel N/P 391 Congress Street Boston, Massachusetts RTNs 3-14803 and 3-35801 December 2019

A Permanent Solution Statement (PSS) was submitted for the site on 3/13/2023. According to the PSS, site was originally part of the South Boston tidal flats and was filled in the 1870s. The area was reportedly filled with material dredged from Boston Harbor and covered with several ft of sand and gravel at the surface. PSS notes that the property remained vacant until it was paved for use as a parking lot in the late 1980s. The text of the PSS notes that “Construction of below-grade space (mostly a parking garage) and foundations for the overall Parcel N/P project has been completed” and that “Construction is in progress for the Parcel P commercial high-rise tower occupying the eastern portion of the project Site
RTN 3-0035801 SubmittalTypePS No Cond Date Rcvd 3/13/2023 PRP SEAPORT N/P TITLE HOLDER LLC Consultant HALEY & ALDRICH, INC

Haley & Aldrich, Inc. (Haley & Aldrich) assessed past and present usage and filling history of the Site through a review of available historical records including Sanborn maps dated 1888 to 2002, aerial photographs from 1938 to 2008, and documentation in “Gaining Ground: A History of Landmaking in Boston.”2 The Site was originally part of the South Boston tidal flats and was filled in the 1870s. The area was filled with material dredged from Boston Harbor and covered with several ft of sand and gravel at the surface. The property and vicinity were developed with a railroad terminal yard including rail spurs, platforms, and freight warehouses in the 1880s. The historical alignment of Congress Street (currently abutting the Site to the north) intersected the north and northeast portions of the Site. The rail spurs and railroad buildings were removed from the Site by the mid-1980s, and the property remained vacant until it was paved for use as a parking lot in the late 1980s. The Site was mainly used for parking, but also served as a construction staging area during the CA/T highway construction in the early 1990s. Congress Street has shifted through the Site over time and was used as a temporary road during the CA/T project as shown on historical aerial photographs appended to the RAM Plan. Support of the elevated Summer Street also changed over time. A steel viaduct for Summer Street was constructed over the southern portion of the Site by 1899. A truss bridge was visible in the 1938 aerial photograph. Old granite block foundations likely associated with the former bridges were uncovered beneath the bridge alignment. A 1969 aerial photograph shows the bridge partially demolished around the time of the railyard decommissioning. Summer Street was subsequently re-constructed as a soil embankment-supported road as shown on a 1978 aerial photograph. Removal of the embankment and construction of the current Summer Street Bridge was conducted in conjunction with the CA/T project during the late 1990s to early 2000s.
The results of the exploration programs indicate the presence of VOCs, SVOCs, petroleum hydrocarbons, and metals in soil at levels above the applicable MCP RCS-1 Reportable Concentrations. No evidence of a point source release was observed, and the soil constituents are likely attributable to the presence of Fill or reworked naturally deposited soil, which is ubiquitous and consistently present in urban areas, and to historic Site use. The Fill typically consists of sand with varying amounts of silt, clinkers, bricks, ash, cinders, wood, concrete, and other debris. The lower vertical boundary of the RTN 3-35801 was defined as the bottom of the Cohesive Fill/Organic Deposits, which generally ranged from approximately El. 3.8 to El. -4.0. The horizontal limits of the RTN 3-35801 Site generally corresponds to the property boundaries of the property with the exception of a small portion of City of Boston sidewalk along Boston Wharf Road on the west side of the Site, as shown on Figure 2. The approximate limits of the RTN 3-14803 Site are also shown on Figure 2. Soil quality of Fill and naturally deposited soil was presented in the 2019 RAM Plan and subsequent RAM Status Reports previously submitted to MassDEP. In general, the RAM remedial excavations resulted in the removal of the Fill, Cohesive Fill, and Organic Deposits comprising the Disposal Site except for areas along the boundaries of the Site beyond the earth support systems, including the back of house area of the Site along the southern boundary. Soil quality data judged representative of naturally deposited soil remaining below the building footprint and of Fill and Cohesive Fill remaining at the lateral limits of excavation are summarized in Tables I and II, respectively.
PERMANENT SOLUTION STATEMENT SEAPORT SQUARE PARCEL N/P 400 SUMMER STREET BOSTON, MASSACHUSETTS RTNS 3-35801 AND 3-14803

BORING HA-M2-17
MARINE DEPOSITS Note: Drill action indicates change in strata at 158.0 ft. Very dense gray silty SAND with gravel (SM), intermixed with weathered bedrock, mps 1.0 in., slightly bonded, no odor, wet -GLACIAL TILL Note: Drill action indicates less gravel or cobbles, possible bottom of glacial till. TOP OF PROBABLE WEATHERED BEDROCK 164.0 FT SEE CORE BORING REPORT FOR ROCK DETAILS C1: Very soft residual soil to completely weathered aphanitic ARGILLITE, bedding extremely thin, no joints, undulating, discolored, open Note: Core barrel jam at 172.0 ft. Stopped C1 at 172.0 ft. C2: Very soft residual soil to completely weathered gray aphanitic ARGILLITE, bedding extremely thin, joints low angle, close to very closed, planar to undulated, discolored, open BOTTOM OF EXPLORATION 177.0 FT

REPORT ON RELEASE ABATEMENT MEASURE (RAM) PLAN SEAPORT SQUARE PARCEL L4 50 EAST SERVICE ROAD BOSTON, MASSACHUSETTS RTNS: 3-19097 AND 3-35310

Soil: Based on previous and recent explorations conducted at the Site, subsurface conditions typically consist of thick sequences (8 to 15 ft.) of mostly granular miscellaneous (urban) fill overlying more impervious cohesive fill or organic and marine soils. Urban fill materials at the Site contain varying amounts of cinders, ash, concrete, brick, wood, and glass fragments. Cohesive fill consists of organic silt or sandy clay. Organic soils consist of soft, dark gray organic silt with varying amounts of clay, sand, shells, and peat. Marine deposits generally consist of silty fine sand with alternating layers of silt and clay and organic silt. Groundwater: Groundwater levels measured in February 2008 indicate that groundwater levels are approximately 7.7 to 8 ft below the ground floor slab of the building and approximately 5 to 6 ft. below existing ground surface outside the building area. The ground surface elevation of the ground surface outside the building ranges from El. 15 at Congress Street to El. 14 at the southwest corner of the building, therefore groundwater elevations range from approximately El. 8 to 9. The direction of groundwater flow is to the south, southeast. Additionally, regional groundwater flow is likely substantially influenced by the presence of the MBTA Silver Line Transitway, the Central Artery/Tunnel (CA/T) Project, and Fort Point Channel. Groundwater levels at the Site are also anticipated to be influenced by the tidal nature of Fort Point Channel and the Boston Harbor. Groundwater levels are influenced by weather conditions, precipitation, the infiltration of surface water runoff, construction activities, leakage into or out of utility pipes, building/highway underdrain systems, localized water recharging, the elevation of the Charles River, and other factors. Seasonal differences in groundwater elevations are expected.

40.1056(2)(b) Summary of the Conceptual Site Model Soil sampling conducted at the Site identified the presence of metals (lead, arsenic, and mercury) above the applicable reportable concentrations in fill samples collected at depths of 6 to 10 feet bgs. Compounds detected at the Site are attributable to historic fill placed at the Site during site filling activities. The fill at the Site meets the definition of ‘Historic Fill’ because it: a) was placed before 1983 (evident from the Seasholes 2003 MIT Press and Sanborn Fire Insurance Maps); b) Historical use of the Site does not indicate the use of metals that may have been released into the subsurface b) contains varying amounts (but not primarily composed of) coal ash and construction debris; c) has detections of metals and PAHs considered consistent with the pervasive use and release of such materials placed prior to 1983; and d) does not contain processing waste, chemical production waste, mineral waste, and/or hazardous waste generated from previous operations or activities at the Site. The vertical extent of the contamination is the thickness of the fill material, approximately 10-14 ft. The horizontal limits of the Site that pertain to the subject RTN for this Permanent Solution are shown on Figure 2. One VOC (sec-butylbenzene) was detected in fill soil at the Site at very low concentrations and at very low frequencies and would not contribute to vapor intrusion into the onsite building. Additionally, VOCs were not detected in site groundwater. Therefore, conditions at the Site are not anticipated to pose risk for vapor intrusion.

40.1056(2)(c) Demonstration That All Sources of OHM Contamination Have Been Eliminated or Controlled Compounds detected at the Site are considered attributable to historic fill placed at the Site and are consistent with background (Anthropogenic Background). Based on Site assessment and characterization work, there are currently no known uncontrolled sources of OHM at the Site that are likely to result in an increase in concentrations of OHM in an environmental medium, either as a result of direct discharge or intermediate transfer of OHM. 40.1056(2)(d) Demonstration That Response Actions Have Been Undertaken to Adequately Assess or Control Subsurface Migration of OHM OHM Compounds of Concern consist of lead, arsenic, and mercury in fill material present at the Site. The contaminants of concern at the Site are consistent with the types of contaminants present in the environment prior to emplacement of the fill, not mobile, and are not anticipated to migrate via the subsurface; as such response actions to control subsurface migration of OHM was not required. 40.1056(2)(e) Demonstration That Response Actions Have Been Undertaken to Adequately Assess and Control NAPL No NAPL is present at the Site. 40.1056(2)(f) Information Supporting That a Level of No Significant Risk Exists OHM in Site soil is consistent with Anthropogenic Background and therefore, a Risk Characterization is not required. 40.1056(2)(g) Information Documenting the Extent to Which Levels of OHM Have Been Reduced To Background

40.1056(2)(h) Copy of Activity and Use Limitation Implementation An Activity and Use Limitation is not required for the Site. 40.1056(2)(i) Demonstration That The Achievement of UCL in Soil is Not Feasible For Permanent Solution With Conditions Where Soils Exceed UCLs at Depths Greater Than 15 Feet The vertical limits of the Site are historic fill from 0 to 14 ft bgs and no UCL exceedance exists. Accordingly, this provision does not apply. Elevated OHM attributable to Anthropogenic Background - OHM in fill soils located throughout the Site is consistent with Anthropogenic Background levels and the fill at the Site meets the definition of ‘Historic Fill’
40.1056(2)(l) Description of Any Operation, Maintenance, and/or Monitoring Required There are no remedial systems required at the Site. Accordingly, no operation, maintenance, or monitoring is required.

PERMANENT SOLUTION WITH CONDITIONS STATEMENT 381 CONGRESS STREET BOSTON, MASSACHUSETTS RTN 3-31898 by Haley & Aldrich, Inc. Boston, Massachusetts on behalf of 381 Congress Street, LLC Boston, Massachusetts File No. 35152-004 January 2015

4.01 Regional Geology The project area is located centrally within the Boston Basin, which is a part of the New England Physiographic Province of the Appalachian Highlands. Generally, this Province is characterized by hilly uplands, sloping irregularly toward the east. The Boston Basin is both a structural and topographic feature. Structurally it consists of a sequence of sedimentary, metamorphic and volcanic rocks surrounded to the north, south and west by older granites and other crystalline rocks. To the east, the basin extends out to sea where its composition and limits are uncertain. Topographically, the Boston Basin is irregularly shaped and relatively flat lowland, sloping very gently toward the east. Overlying the bedrock, the bulk of the Boston Basin is filled with sediments of estuarine, marine and glacial origin. Within Boston and immediately surrounding areas, large portions of the naturally deposited sediments are overlain by fill. The typical naturally deposited soil profile present below manplaced fills consists of marsh deposits such as organic silt and peat overlying marine clay and sand. The underlying glacial deposits typically consist of outwash sand and till. A relatively thick glaciomarine deposit, consisting of a mixture of clay, silt, sand and gravel, is also present in some locations near the shoreline within the central portions of the Boston Basin, overlying the glacial deposits. The marine and glaciomarine deposits are of post-glacial age and are relatively young in terms of geologic time. The glacial deposits present within the Boston Basin may represent several episodes of glaciation, the youngest one of which came to a close toward the end of the Pleistocene Epoch, approximately 12,000 years ago. Subsurface explorations carried out recently for other projects located within the Boston Basin confirm the complex depositional sequence described above.

4.02.1 Fill The proposed reaches are generally located along street right-of-ways which have likely undergone several episodes of filling, grading, and utility trench backfilling through their history typical of rightofways located in an urban setting. As a result, Fill was encountered in all of the test borings. The Fill encountered varies widely in thickness, density consistency, and composition. For the recent borings the thickness of Fill, including the thickness of the surficial asphalt and concrete roadway, varied from 7 ft at the shallowest to greater than 18 ft. The bottom of the Fill deposit was not fully penetrated in all borings. Because the test borings were conducted along street and sidewalk right-of-ways, the Fill typically includes a 0.4 ft to 0.5 ft thick layer of asphalt at the ground surface. A cobblestone layer was encountered just below the asphalt layer in borings HA-FPCO9 and HA-FPC-14. In some cases the Fill in the test boring log is described as granular or cohesive. More specific description of each follow: Granular Fill generally consists of a very loose to very dense poorly graded to well graded SAND with varying amounts of clay, silt, and gravel. Cohesive Fill generally ranged from very soft to very stiff SILT with varying amounts of clay, sand, and gravel. The Fill contains numerous brick, glass, leather, coal, and ash fragments and particles. Large obstructions, cobbles, or boulders were not encountered in the borings, however due to the nature of the Fill they may be present along the proposed pipe alignments

4.02.2 Organic Deposit An organic deposit was encountered in HA-FPCI5 at a depth of 13 ft below ground surface. The boring was terminated at a depth of 15 ft and the layer was not fully penetrated. The deposit consisted of medium stiff SILT with roots.

4.02.3 Estuarine Deposit Estuarine deposits were encountered in borings HA-FPCO9 and HA-FPC17. The deposit ranged from stiff SILT to medium stiff sandy CLAY.

4.02.4 Marine Deposit Marine deposits were encountered in boring HA-FPCO5, HA-FPCO7, and HAFPC-17. The marine deposit ranges from of soft lean CLAY to medium stiff SILT to medium dense SAND with silt. Trace shells, roots, and other organic material was encountered

4.03 Water Levels The depth to water in the installed observation well ranged from 7.0 ft to 7.6 ft below the ground surface. In addition Boston Wharf Company has installed several observation wells in the area. These wells indicate that the water levels range from El. 5 to El. 9 (5 ft to 14 ft below ground surface) across the site. Groundwater levels may fluctuate due to variations in season and precipitation, leakage into or out of existing utilities and utility bedding materials, adjacent construction activities, and other environmental effects. As a results water levels encountered during construction may vary from those recorded in the observation well and borings during the observation period.

Sixteen MADEP disposal sites exist within the immediate area of the alignment, as shown in Figures 2A and 2B....

Gillette Manufacturing, Inc., 1 Gillette Park (RTNs 3-4365, 3-11418, 3-11801, 3-12233, 312352, 3-12767, 3-12777, 3-13952, 3-14687, 3-15548, 3-17924, 3-11312, Map ID 1 (100 Dorchester Ave)): This site is located adjacent to the proposed sewer separation alignment and consists of a large manufacturing facility for Gillette Manufacturing, Inc. (Gillette). Although the property is located near the Fort Point Channel Sewer Separation alignment, the site consists of approximately 18.5 acres of land, therefore several of the spills and/or releases reported at this site occurred greater than 0.1 mile from the alignment. Numerous response actions have been conducted at the Gillette site to address several releases of OHM reported to MADEP. Each release and/or response action was assigned a separate RTN number by MADEP. In 1996, GEI Consultants, Inc. combined two existing RTNs (RTNs 3-12352 and 3-12767) under the initial RTN for the site (RTN 3-4365) to streamline response actions being conducted west of Gillette Building Z. In addition, RTN 3-15548 was combined with RTN 3-4365 in 1997. Following the discovery of VOC contamination to the east and west of Gillette Building Z, RTN 3-4365 and its associated RTNs were combined into RTN 3-11312 to evaluate potential response actions at the site. Currently, response actions at the site are being addressed under RTN 3-11312.
RTN 3-4365: Construction of the CA/T required Gillette to undergo a Facilities Relocation Project to relocate facilities impacted by construction of the CA/T. Analytical testing conducted at the site during the design phase indicated the presence of VOCs and TPH in site soils above reportable concentrations. MADEP was notified of the condition in December 1992 and placed the site on the list of Locations to be Investigated and was assigned RTN 3-4365. Three RAMs were conducted under RTN 3-4365 to address OHM-contaminated soil and groundwater encountered at the site during the construction phase of the Facilities Relocation Project. RAM activities included the excavation for a new circulating water system and fuel oil storage vault and the removal of an existing UST. In April 1996, the site was classified as a Tier II Disposal Site. In addition, between 1994 and 1997; RTNs 3-12352, 3-12767, and 315548 were combined with RTN 34365 to address contamination located across the property to the west of Gillette Building Z. In May 1999, RTN 3-4365 was combined with RTN 3-11312 to address contamination located across the majority of the site
RTN 3-11418: On 4 August 1994, MADEP was notified of a 120-day reporting condition for the presence of VOCs, PAHs, and lead in soil and VOCs in groundwater. The contamination was discovered during Gillette's environmental due diligence investigation for acquisition of the property. At the time of the discovery of the contamination, the site was owned by A Street Realty Trust. During the course of the due diligence investigation, Gillette discovered VOC contamination on its property located adjacent to RTN 3-11418. Gillette purchased the property in the Fall of 1995 and combined RTN 3-11418 with 3-11312 to form the Sobin Park South Disposal Site. RTN 3-11312 addresses the VOC contamination and is described below.
RTN 3-11801: On 2 November 1994 MADEP was notified of a sudden release of hydraulic oil from a trash compactor located adjacent to the east side of Gillette Building Z (approximately 0.13 mile east of the Fort Point Channel Sewer Separation alignment). IRA activities were initiated to contain and absorb the released oil. GEI Consultants concluded that that IRA activities had resulted in a permanent solution and that background had been achieved at the site. On 21 December 1994, a Class A-1 RAO was filed for the site
RTN 3-12352: In April 1995, IRA activities were initiated in response to the sudden release of approximately 10 to 20 gallons of oil from a previously unknown and abandoned UST located west of Gillette Building Z (approximately 0.1 mile east of the Fort Point Channel Sewer Separation alignment). The release occurred during an excavation being conducted for the Circulating Water System as part of the Facilities Relocation Project. This RTN was combined with RTN 3-4365 for future assessment activities following the IRA completion.
RTN 3-12767: In August 1995 URAM activities were initiated in response to the discovery of a previously unknown and abandoned UST containing a mixture of soil and oil located west of Gillette Building Z (approximately 0.13 mile east of the Fort Point Channel Sewer Separation alignment). The UST was discovered while excavating for the installation of a pipeline for a Circulating Water System as part of the Facilities Relocation Project. This RTN was combined with RTN 34365 for future assessment activities following the URAM completion.
RTN 3-12777: On 4 August 1995, MADEP was notified of the release of approximately 50 to 60 gallons of diesel fuel to the pavement and a truck wash pad sump from a ruptured diesel fuel tank of a dump truck located in a parking lot adjacent to the North Dock of Gillette Building Z (approximately 0.18 mile east of the Fort Point Channel Sewer Separation alignment). IRA activities were initiated consisting of spreading sand in the release area to absorb the oil, collecting the oily sand, and pumping water, oil and sludge from the truck wash sump and nearby catch basins into an on-site fractionation tank for off-site disposal. In addition to conducting these activities, sediment in the bottom of the nearby catch basins was excavated for off-site disposal. A Class A-1 RAO was filed with MADEP on 11 October 1995.
RTN 3-13952: On 28 June 1996 MADEP was notified of the presence of dense non-aqueous phase liquid (DNAPL) in monitoring wells installed directly east of Gillette Building Z (approximately 0.17 mile east of the Fort Point Channel Sewer Separation alignment). DNAPL was encountered in wells installed in the overburden and bedrock strata and consisted of chlorinated solvents. MADEP assigned RTN 3-13952 to the release to track IRA activities. IRA activities consisted of additional assessment of the extent of chlorinated VOC contamination and the installation of recovery wells. A Phase II investigation determined the source of the VOC contamination was a dry well located within Gillette Building Z. On 22 June 1999, RTN 3-13952 was combined with RTN 3-11312 to address site-wide VOC contamination.
RTN 3-14687: On 3 January 1997 MADEP was notified of the release of approximately 20 gallons of sharpening oil on to a concrete apron outside the North Dock of Gillette Building Z (approximately 0.18 mile east of the Fort Point Channel Sewer Separation alignment.) Clean Harbors was contacted to clean up the site. GEI Consultants concluded that the spilled oil appeared to have been completely recovered and there was no evidence of oil migration beyond the apron or to the soil below the apron. A Class A-1 RAO was filed with MADEP 20 February 1997.
RTN 3-15548: In April 1997, MADEP was notified of a 72-hour reportable condition as a result of headspace readings exceeding 100 ppm during a UST removal located west of Gillette Building Z (approximately 0.06 mile east of the Fort Point Channel Sewer Separation alignment). IRA and RAM activities included the removal of the UST and off-site disposal of approximately 37 cubic yards of contaminated soil. This RTN was combined with RTN 34365 for future assessment activities following IRA and RAM completion.
RTN 3-17924: On 13 January 1999, MADEP was notified of a 120-day reportable condition for the exceedence of one PAH encountered during a geotechnical investigation and soil precharacterization program for a proposed extension to Gillette's South Dock building (approximately 0.15 mile east of the Fort Point Channel Sewer Separation alignment). A Method 1 Risk Characterization was performed using the data collected during the precharacterization program. As the results of the Method 1 Risk Characterization indicated a condition of No Significant Risk existed for the site, a Class B-1 RAO was filed with MADEP on 14 May 1999.
RTN 3-11312: On 14 July 1994, MADEP was notified of the discovery of VOCs including vinyl chloride and trichloroethene (TCE) in excess of reportable concentrations in groundwater and TCE in excess of reportable concentrations in soil. The source of the VOCs was attributed to previous unidentified spills of chlorinated solvents. A Phase I Initial Site Investigation and Tier Classification were submitted to MADEP in 1995. The site was classified as a Tier II Disposal Site.
RTN 3-11312 has been designated as the primary RTN for the Gillette site. Several releases were combined and incorporated into RTN 3-11312 in 1996. Additionally, RTN 3-4365 (described above), a Tier II Disposal Site located on Gillette property, was combined with RTN 3-11312 in May 1999. Response actions at the site are currently being conducted under this RTN. A description of the extent of site-wide contamination and current response actions is listed below.

Chlorinated solvent contamination (primarily TCE) of site soil and groundwater has been associated with both historical surface spills and releases to a basement dry well at the Gillette facility. A Phase II Comprehensive Site Assessment performed by GEI (10 May 1999) identified two areas of contamination, designated "Area A" and "Area B". "Area A" is located between A Street and Building Z and incorporates shallow overburden deposits and the shallow aquifer. "Area B" is located beneath, east and west of Building Z, and encompasses both shallow and deep overburden deposits, bedrock, and both shallow and deep aquifers. Area A: VOCs identified in shallow soils, and dissolved VOCs identified in groundwater have been attributed to unknown surface spills of chlorinated solvents. Identified VOCs are limited to the fill and silt deposits above the marine clay, which acts as an impermeable barrier to downward contaminant migration. Maximum concentrations of TCE in soil and groundwater were identified 6-10 feet below ground surface. The identified VOC contaminant plume encompasses approximately 40,000 s.f. (Area A). Vertical migration of contaminants has been impeded by the marine clay at approximately 40 feet below ground surface. Lateral migration of TCE in the shallow soils and shallow aquifer has proceeded radially. Based on field evidence (soil/groundwater quality data and groundwater contours), GEI concludes that the contaminant plume does not appear to be expanding laterally. Therefore it is unlikely that the chlorinated solvent plume has migrated to A Street.

Area B: Chlorinated solvents have been detected within the fill, silt, clay, glacial till, and bedrock in the vicinity of the former dry well in the basement of Building Z. It has been estimated that thousands of gallons of solvents may have been released to the dry well. High concentrations of dissolved TCE were identified in shallow fill and silt deposits, as well as within groundwater obtained from the shallow aquifer in Area B. DNAPL was also observed and recovered from the shallow aquifer directly east of Building Z (RTN 3-13952). Dissolved TCE and DNAPL have also been observed in the clay directly east of Building Z. Dissolved chlorinated VOC contamination is present in the bedrock both east and west of Building Z, and in glacial till west of Building Z. DNAPL has been identified in the bedrock immediately east of Building Z, and likely beneath Building Z. GEI has concluded that the primary pathway of chlorinated solvents to the deep aquifer appears to be structural piles installed to support Building Z. DNAPL and dissolved concentrations of TCE have migrated both laterally and vertically from the source area (dry well in Building Z basement). Due to the presence of highly weathered and fractured bedrock below the site, DNAPL has potentially migrated a few hundred feet in depth. Lateral migration of both separate and dissolved phase TCE within the deep aquifer has proceeded radially. As of October 1998, concentrations of TCE within the deep aquifer had migrated east to within 75 feet of A-Street, and west to Fort Point Channel. Groundwater and soil quality data suggest that, at the lateral fringes of the contamination plume, VOC concentrations decrease dramatically, likely the result of dispersion, sorption onto soil, and biodegradation, which is evidenced by the presence of dichloroethene and vinyl chloride in site wells. GEI has concluded that lateral migration of TCE (primarily dissolved phase) in the deep aquifer to the north, east, and south has likely ceased. However, continuing westward migration of separate phase and dissolved TCE is likely.

As part of an IRA to investigate DNAPL encountered at the Gillette facility, GEI is currently monitoring/testing groundwater at the site. Recharge wells have been installed on the site to both control vertical settlement of the Gillette buildings and to limit the westerly migration of TCE in the glacial till and bedrock. Use of the site dewatering/recharge system was discontinued in August 2002. Environmental Resources Management (ERM) was retained to prepare a Phase III Remedial Action Plan for the site. The Phase III was submitted to MADEP on 29 December 1998. The objectives of the Phase III report were to remediate DNAPL to the maximum extent possible, and to mitigate dissolved phase contaminant migration off the Gillette property. Bioremediation was selected as the preferred remedial alternative (over pump and treat) due to costeffectiveness (both short term and long term), implementation feasibility (would prevent building settlement; difficult to extract groundwater using pump & treat), and the ability to achieve migration remedial action objectives in a timely manner. However, ERM concluded that bioremediation would not constitute a permanent solution since source (DNAPL) control methods were not feasible for the disposal site in 1998. Additionally, as part of RAM activities conducted by ERM, a bioremediation pilot test was initiated between Building Z and Fort Point Channel in August 2001. Results of the pilot test were not located during this file review. However, sampling of specific site monitoring wells by ERM indicated that on 1 March 2001, elevated concentrations of TCE (900 ppb) were identified in well MW-804B (southeast of the source area). Previous analytical results indicate TCE concentrations identified in MW-804B were less than 2 ppb. This may indicate potential southeast TCE plume migration. MADEP records indicate that the Gillette site is currently under Phase V of the MCP. The site is classified as a Tier II disposal site.

No Location Aid, West Second Street Dorchester Avenue (RTN 3-11446, Map ID 6 (100 Dorchester Ave)): This site is located adjacent to the Fort Point Channel Sewer Separation alignment. Trigen Boston Energy Corporation (Trigen) encountered a black tarry substance on soil and groundwater during an excavation to repair a steam line. Trigen notified MADEP of the intent to conduct the work as a URAM on 10 August 1994. MADEP assigned the URAM RTN 3-11446. According to MADEP's OHM Release Log Form, Trigen was to contact Cyn Environmental to vacuum out water and place dumpster on-site to contain soils until completion of the repair. On 20 September 1994, MADEP issued a letter to Trigen regarding the performance of URAMs pursuant to MGL c. 21E and 310 CMR 40.0000. No URAM Status Reports or Completion Reports were on file with MADEP. The RTN is currently listed in the MADEP database as a Tier ID site indicating the responsible party failed to provide a required submittal to MADEP by the specified date. As this RTN addresses a URAM, the extent of contamination was not delineated. Therefore it is unclear whether this release will impact the Fort Point Channel Sewer Separation alignment.

SVOC, EPH, and/or lead contamination encountered in fill samples collected along the FPC Sewer Separation alignment are commonly associated with urban fill material, which is ubiquitous throughout Boston and surrounding cities and towns. Several of the test borings encountered trace amounts of brick, glass, ash, cinders, and/or other debris. In general, the contaminant concentrations encountered are typical of urban fill material. Therefore, it is likely that the majority of the contamination encountered along the FPC Sewer Separation alignment is attributable to the quality of the fill material, the source of which is unknown, and the historical commercial and industrial use of the area. However, three areas should be noted due to the nature of the contaminants encountered:

1) HA-FPC10: Petroleum odors were observed while drilling test boring HA-FPCIO. Soil sample HA-FPCIO-S4, collected at the groundwater table, encountered VOC, VPH, and arsenic contamination in addition to SVOC, EPH, and lead contamination. HA-FPCO10 was advanced in the vicinity of two documented petroleum releases (RTN's 3-0636 and 3-14890), and detected VOCs are consistent with petroleum constituents. Therefore, it is likely that the compounds detected in HA-FPC10-S4 are related to both the quality of the urban fill and the release of petroleum in the area.
2) HA-FPC14: High levels of trichloroethylene were detected in soil sample HA-FPC14SS, collected at the groundwater table. As there are no documented releases of oil and/or hazardous materials in the immediate vicinity of HA-FPC14, the source and extent of trichloroethylene contamination is unclear at this time.
3) HA-FPC17: High levels of SVOCs were detected in soil sample HA-FPC17-S2. Although VOCs, EPH, and VPH were not detected, the case narrative in the laboratory data indicates that the soil sample contained non-homogeneous fractions and the sample analyzed for SVOCs contained a petroleum odor. Two releases of petroleum (RTN's 311446 and 3-11777) have been documented adjacent to this test boring, however the RTNs address URAMs which are currently not in compliance with the MCP.

Therefore, it is likely that the SVOCs are related to the petroleum releases, the source, nature and extent of which is unknown. A review of chemical analyses from groundwater samples collected within the vicinity of the FPC Sewer Separation alignment and available in the public record have identified EPH carbon ranges and target analytes, VPH carbon ranges and TPH above applicable RCGW-2 Reportable Concentration. Additionally, VOCs and/or VPH target analytes were detected above Federal MCLs in groundwater samples SB-6, MW-28 and MW-29. However, it should be noted that the majority of the groundwater data reviewed in the public record was collected prior to 2000

Low levels of dissolved lead were detected in groundwater in the vicinity of 34 Farnsworth Street. As there are no identified point sources of groundwater contamination for dissolved lead in the vicinity, it is likely that the lead is associated with contact of groundwater with the urban fill as two soil fill samples collected from below the water table at explorations HA-FPC10 and HA-FPC 11, both on Farnsworth Street, contain leachable lead in excess of Hazardous Waste Criteria. Therefore, elevated and leachable lead in urban fill in this area may be impacting groundwater in this area. Low levels of dissolved barium were detected in groundwater in the vicinity of 51 Sleeper Street. As there are no identified point sources of groundwater contamination for dissolved barium in the vicinity, it is likely that the barium is associated with contact of groundwater with the urban fill as three soil fill samples collected from below the water table at explorations HA-FPC10 and HA-FPC11, both on Farnsworth Street, contain elevated levels of barium when compared to the remainder of the FPC Sewer Separation alignment. Therefore, elevated barium in urban fill in this area may be impacting groundwater in this area.

Based on the data provided in Section V as well as observed field conditions and historical site use, environmental conditions along portions of the FPC Sewer Separation alignment have been influenced by historical filling of the site and documented releases of oil and/or hazardous material. The following Sis a brief summary of environmental/ regulatory factors that will determine the construction impact on this portion of the project:

HA-FPC01 SVOCs, EPH, metals RCS-1 Fill soils
HA-FPC05 SVOCs, metals RCS-1 Fill soils
HA-FPCO9 SVOCs, EPH, metals RCS-1 Fill soils (attributed to coal ash and/or cinders, and therefore unlikely reportable to DEP, per 310 CMR 40.0317(9))
HA-FPC10 VOCs, SVOCs, EPH, RCS-1 Fills soils and mineral oil release at 24 Farnsworth Street VPH, metals (RTN 3-0636)
HA-FPCIO NA (exceeds RCRA HA-FPC10 NA Hazardous Waste Criteria for leachable lead) Fill soils
HA-FPC11 SVOCs, EPH, metals RCS-1 Fill soils (attributed to coal ash and/or cinders, and therefore unlikely reportable to DEP, per 310 CMR 40.0317(9))
HA-FPC11 NA (exceeds RCRA Hazardous Waste Criteria for leachable lead) Fill soils
HA-FPC14 VOCs, SVOCs, EPH RCS-1 Fill soils and unknown source of VOCs (trichloroethylene)
HA-FPC15 SVOCs, EPH RCS-1 Unknown source of petroleum
HA-FPC17 SVOCs RCS-1 Unknown petroleum release (RTN's 3-11446 and 3-11777)
Petroleum and Mineral Oil on Pittsburg St, Farnsworth St, and Congress St

BOSTON WATER & SEWER COMMISSION FORT POINT CHANNEL COMBINED SEWER OVERFLOW CONTROL PROJECT BWSC Contract No. 95-206-014 FINAL HAZARDOUS MATERIALS ASSESSMENT REPORT CONTRACT 95-206-014 File No. 28501-530
June 2005

MARINE DEPOSITS Note: Driller washed through the interval accidentally while we were attempting to ventilate the workspace. -MARINE DEPOSITS Very stiff gray brown lean CLAY (CL), mps<0.042 nummn, no structure, no odor, wet. Same as SI0 except stiff, Very stiff gray brown lean CLAY with sand (CL), mps 2.0 mm, no structure, no odor, wet. Same as S12. Hard gray brown sandy lean CLAY with gravel (CL), maps 3/4 in., no structure, no odor, wet. -GLACIOMARINE DEPOSITS Same as above.. -GLAC1OMARINE DEPOSITSSame as S14. Density is increasing, mps I 1/4 in. Slightly more coarse gravel. Gravel is subangular Hard gray to olive gray gravelly lean CLAY with sMand (CL), mps 2 in., no structure, no odor, wet. Gravel is subangular. -GLACIAL TILL Similar to S17. Becoming very hard. Similar to S17. Advancing borehole with 3 in. casing to rock surface and running core. TOP OF BEDROCK 72.0 FT SEE CORE BORING REPORT FOR ROCK DETAILS SEE TEST BORING REPORT FOR OVERBURDEN DETAILS Advanced roller bit from 70.5 to 72.9 ft. Drilling action indicates strata change to possible bedrock at approximately 72.0 ft. 3.0 in. casing is seated at 72.9 ft. TOP OF BEDROCK 72.0 FT 72.0 -BEDROCK Cl: Moderately hard to medium hard, slightly weathered, light gray. aphanitic ARGILLITE. The description of the rock core fromn 72.9 to 74.9 ft has been compromised due to the poor recovery from the run. Core barrel jammed at 74,9 ft. C2: Moderately hard, slightly weathered, light gray. aphanitic ARGILLITE. No bedding present. Low angle joint set, spacing is extremely close, smooth and planar. 76.9 BOTTOM OF EXPLORATION 76.9 FT Note: * Denotes use of 300 lb hammer.

Boring No. B-100 PHASE I REDEVELOPMENT A & MIDWAY STREETS
SOIL PRECHARACTERIZATION REPORT 2 TO 22 MIDWAY STREET A & MIDWAY PROPERTIES PHASE I REDEVELOPMENT BOSTON, MASSACHUSETTS VOLUME I OF II by Haley & Aldrich, Inc. Boston, Massachusetts for A Street Properties III, LLC Boston, Massachusetts File No. 26135-101 September 2002

SOUTH END LANDMARK DISTRICT

"The area between the original shore lines on the so-called natural soils, one location out of eight locations was found where piles were used."

"After excavations had progressed for a few days it became apparent that many of the structures in the South End were founded directly on the underlying soils, and in many cases these soils were clay.... The entire South End Area is underlain with blue clay of varying consistency, from hard to soft."

"many of the structures in the South End were founded directly on the underlying soils, and in many cases these soils were clay."

Investigation of Subsoil and Foundation Conditions, Boston Redevelopment Authority, SOUTH END PROJECT MASS. R-56, SOUTH END URBAN RENEWAL AREA (December 27, 1963).

MA Chapt. 772, An Act Establishing the Boston Landmarks Commission (1975)

"The South End Landmark District is the largest intact Victorian rowhouse district in the United States. It represents over 300 acres of land that was filled along the necklands and developed during the mid-19th century. It is a substantially intact area of mid-19th c. row houses. The landmark district is roughly bounded by the Southwest Corridor right-of-way, Tremont St., East Berkely St. Washington St., Harrison Ave., and Northampton/Camden Streets."

"The Commission on November 14, 1983, fallowing recommendation of the Study Committee, voted to designate the South End Landmarks District and the South End Protection Area, which designation were approved by the Mayor on November 16, 1983."

DILEANATION

At Tremont and Herald Streets, blue clay extends to 110' below the surface at which point very compact fine sand, gravel and little shale exists.
At Tremont and Northampton Streets, blue clay extends to 122' below the surface with gravel and clay to 141' where ledge is found.
At Washington and West Canton Streets, soft clay extends to 75' below the surface where sand, gravel and clay is found.
At Washington and Dover Streets, soft blue clay extends to 71' below the surface; between 71' below and 99' medium stiff blue clay with veins of fine sand is found, and between 99' and 110' below, firm fine sand exists.
Deep borings adjacent to Washington Street indicate the clay strata ranges from 50' to 55' thick. Peat also exists in four specific across adjacent to Washington Street.
At Harrison Avenue and East Lenox Streets, soft blue clay extends to 103.5' below the surface, with loose medium sand to 107.0'; firm medium gray sand and gravel to 126.0', and hard coarse sand and gravel to 132.0' below.
At Albany and Randolph Streets, blue clay extends to 130.0' below the surface, with medium sand and some fine gravel to 131.5', and fine sand, little clay and some fine gravel to 136.9' below.
At Tremont and West Springfield Streets, soft blue clay extends to 85.5' below the surface; hard fine sand and gravel is found between 85.5' and 87.0' below.
Deep borings adjacent to Tremont Street indicate clay strata to be (1) 92'; (2) 120'; (3) 73"; (4) over 60'. Peat is found between Cunard Street and Coventry Street, also between Benton Street and Northampton Street, and near Herald Street.
At Shawmut Avenue and Herald Streets, blue gray silty clay extends at least to 71.5' below the surface, as is also the case at Washington Street and Herald Street.
At Washington Street and Massachusetts Avenue, blue gray silty clay with little sand extends at least to 72.0' below the surface.
At Harrison Avenue and Worcester Square, soft blue clay extends to 114.0' below the surface; very hard fine sand, gravel and stones are found up to 121.0' below the surface.
At Harrison Avenue and East Dedham Street, soft blue clay extends to 74.3' below the surface; boulder hard pan is found down to 76.0' below, with refusal encountered at 76.0' below.
The Harrison Avenue soils profile above the clay, in general indicates: 4' to 17' - fill 4' to 19.5' = peat and silt. Deep borings in the vicinity of Harrison Avenue indicate clay strata to be between 57' and 88.5' thick. There are a few locations where the peat strata is not encountered; namely, in the area between Savoy and Dover Streets.
At Albany and Stoughton Streets, blue clay extends to 87.5' below the surface; fine sand, some clay and medium coarse gravel is found between 87.5' and 95.0' below, with refusal encountered at 95.0' below,
The Albany Street soils profile, in general shows the following above clay: 4ft to 24ft = fill; over 3.5' to 45' = mud or silt; or 4' to 17' - peat and silt. Deep borings in the vicinity of Albany Street indicate the clay strata to be between 70' and 110' thick.

Investigation of Subsoil and Foundation Conditions, Boston Redevelopment Authority, South End Project Mass. R-56, South End Urban Renewal Area (December 27, 1963)

Examination of existing piling showed some rotting, indicating probable lowering of the water levels in some areas, but, generally, water levels are as would be expected from the elevation cutoff and location of piles. Actual lengths of piles are not known. On-site observations and information obtained from the records of the Boston Building Department as to conditions of structures supported by pile foundations indicate, that although the piles, in general, were in good condition, a large proportion of these structures were considered in such poor condition as to be condemned. The fault, however, appears not in the piles but largely in poorly constructed foundation walls.

In general, structures over three stories in height must be on piles. Foundation walls and piles of existing buildings to be continued in use should be thoroughly examined."

Investigation of Subsoil and Foundation Conditions, Boston Redevelopment Authority, South End Project Mass. R-56, South End Urban Renewal Area (December 27, 1963)

1965

"During this investigation and study, a total of 15 new soils borings were made finding: Silt sizes range from 0.07 mm to 0.005 mm; Clay sizes are smaller than 0.005 mm; Colloids are smaller than 0.001 mm

No. 6A - 106-108 East Canton Street - rear of building
Boring No. 6A
Sample No. 4
Depth = 34' to 38.5'
Blow Count - 13/ft
Stiff yellow clay
Clay & silt, some fine sand

No. 8A - 373 Columbus Avenue - rear of building
Boring No. 8A
Sample Noe
Depth - 15.5' to 17'
Blow Count = 2/ft
Very loose sandy peaty silt
Clayey organic silt

No: 9 - 72 Warren Avenue - Firehouse = rear of building
Boring No. 9
Sample No. 6
Depth - 26' to 28'
Blow Count - 21/ft
Very stiff blue clay with trace of gravel
Clayey sandy silt

No. 15 = 21 Rutland Square - rear of building
Boring No. 15
Sample No. 6
Depth - 22.5' to 24'
Blow Count - 4/ft
Soft blue clay
Clay and silt, some fine sand

Investigation of Subsoil and Foundation Conditions, Boston Redevelopment Authority, SOUTH END PROJECT MASS. R-56, SOUTH END URBAN RENEWAL AREA (December 27, 1963).

For South End, "soils information available from numerous soil borings that have been made in past years throughout the South End Project Area provided a basis for development of a generalized subsurface profile in the area. The soils and rock strata from existing ground surface downward are as follows:

a. Two (2) to thirty (30) feet of "man made" fill varying in character from very loose rubbish and cinders to medium-dense sand and gravel
b. Either:
- one (1) to thirty five (35) feet of river bottom or flood plain deposited organic silt, peat and/or mud; or
- one (1) to twenty (20) feet of sand and gravel.

(An Exhibit follows that indicates the approximate limits of the organic soils beneath the fill.)

c. Either
- one (1) to sixty (60) feet of glacial till consisting of sand, gravel, and clay, or
- up to one hundred twenty (120) feet of stiff to very soft fluvio-glacial deposits of "Boston Blue Clay"
d. Cambridge slate bedrock formation consisting of soft to hard slate, shale, and siltstone rock

The effects of the tide levels in the Roxbury Canal influence the water table at this site. The ground water varies between El. + 1 and El. + 13."

BOSTON REDEVELOPMENT AUTHORITY ENGINEERING REPORT ON THE PRELIMINARY DESIGN OF PROJECT IMPROVEMENTS, SOUTH END PROJECT, Project No. Mass. R-56, MAGUIRE AND ASSOCIATES, ENGINEERS (JULY 1965)

Soil Profile for Washington Street (South End, Boston)

Soil Profile for Harrison Ave (South End, Boston)

"Due to access limitations, the borings were performed utilizing portable (tripod-mounted) boring equipment. Boring B-1 which was performed outside the building within the concrete patio area adjacent to Washington Street encountered refusal within what appeared to be building rubble/debris at a depth of approximately 2 feet below existing grade. Three additional attempts were made at various locations within the general vicinity of B-1 (borings B-1A through B-1C), with each attempt encountering refusal at depths ranging from approximately 2 to 4 feet below existing ground surface. At boring B-2, the driller attempted to core through slab within the mechanical room in the northeast portion of the basement space. However, the driller was unable to penetrate the slab at a depth of approximately 32 inches, and this location was therefore abandoned. Boeing B-2 was terminated within the concrete slab at approximately Elevation +4.3.

Boring B-3 was completed at the southern end of the building and was advanced to a depth of 8.5 feet below the basement slab and terminated within a natural deposit of Boston Blue Clay. The boring encountered a 4-inch thick slab directly underlain by a 2-foot thickness of granular fill consisting of a loose brown/black sand and silt with a trace gravel and containing trace ash and cinders. A 3-foot thick natural organic silt and peat deposit was encountered beneath the fill. A blue-yellow silty clay deposit (Boston Blue Clay) was encountered at a depth of 5 feet below the top of the basement slab. A two-inch diameter PVC monitoring well with a slotted screen set to intercept the surface of the groundwater was installed in the completed B-3 borehole.

Groundwater was observed at a depth of approximately 2 feet below the top of slab at about Elevation +7. In addition, depth to groundwater was measured in Boston Groundwater Trust (BGwT) monitoring well 20J-0356 located at the corner of Washington and East Concord Streets and GZ-101 at depths of 11.6 feet and 11.3 feet below grade which is equivalent to approximately Elevations +5.4 and +5.2, respectively. The groundwater is likely perched within the relatively impervious organic and/or clay deposits. Based upon the measurement of groundwater levels at the subject site, and a review of BGwT database for monitoring wells in the vicinity of the site, the groundwater gradient at the subject site is inferred to flow towards the east-northeast. We anticipate that future groundwater levels across the site may vary from those described in this report due to factors such as normal seasonal changes, runoff, particularly during or following periods of heavy precipitation, and alterations of existing drainage patterns. Further, we anticipate that groundwater levels are locally influenced by the depth to the impervious organic and clay deposits.

The nearest surface water body is the Muddy River which is located approximately 0.95 miles to the westnorthwest of the subject site. The closest area to the subject site designated as Protected Open Space is the South End Burial Ground located approximately 190 feet to the northeast of the subject site. No areas designated as solid waste sites (landfills) are noted as being located within 1,000 feet of the site. The Boston University School of Medicine is located approximately 770 feet to the southeast of the subject site. "

"The presence of TCE was detected in soil gas samples SG-1, SG-2, and SG-3 at concentrations of 245 micrograms per cubic meter (ug/m3), 13 ug/m3 and 9.03 ug/m3, respectively. The presence of PCE and TCE was identified in each of the four indoor air samples tested. In basement samples AS-1 and AS-2, PCE and TCE were detected at the following concentrations: PCE; 1.2 ug/m3 and 1.64 ug/m3, TCE; 1.39 ug/m3 and 1.34 ug/m3."

IMMEDIATE RESPONSE ACTION COMPLETION, COMPREHENSIVE PHASE I, PHASE II AND PHASE III REPORT IN SUPPORT OF A PERMANENT SOLUTION WITH CONDITIONS STATEMENT, ANNA BISSONNETTE HOUSE, 1640 WASHINGTON STREET, RTN 3-29232, BOSTON, MASSACHUSETTS (MARCH 22, 2016).

"The Site consists of approximately 5 acres of land which is bounded by Washington Street to the north, East Lenox Street to the west, Reed Street to the south, and Northampton Street to the east. The Site is located on the U.S. Geological Survey (U.S.G.S.) Boston South, Massachusetts Quadrangle Map (1987) at U.T.M. coordinates 328,750 mE, 4,688,813 mN; and Latitude 42'20'06" N, Longitude 71 004'37"W. The property is owned by the U.S. Department of Housing and Urban Development. The Massachusetts Housing Finance Agency (MHFA) is the interim asset manager and agent for the Site. Grant Manor consists of six multi-family residential buildings which contain a total of 180 apartment units. The buildings include a seven-story high-rise building, (1820- 1850 Washington Street), a four-story mid-rise building (20 East Lenox Street), and four two-story townhouse buildings (80-90 Northampton Street, 100-110 Northampton Street, 5- 15 Reed Street, and 21-27 Reed Street). Figure 2 in Appendix A shows the buildings and surrounding streets.

In December 1994, CDW prepared a Preliminary Site Assessment (PSA) report for the Site. CDW had reviewed historical Sanborn maps, aerial photographs, and available records at various city agencies. According to the information available, the Grant Manor complex was constructed in 1971. Sanborn maps from 1938, 1914, 1897, and 1885 indicated that the Site was previously subdivided into many smaller parcels which contained a variety of residential, retail, and commercial structures. The Site has been occupied by a stable, wagon and blacksmith shops, tin shop, fire station, retail stores, laundry shop, hotel, parking garage, storage warehouse, and print shop in the past. A parking garage containing an auto repair shop and a paint spray booth was also previously located on-site at the corner of Northampton Street and Reed Street.

The average depth to groundwater on the Site is approximately 6.9 feet. The groundwater was determined to be flowing to the south-southeast. The results of the in-situ permeability test indicated that the permeability in well MW-I is 0.126 feet/day. The observed permeability is consistent with permeability for fine sand.

Most of the soil samples obtained in the June 1997 investigation reported TPH and total lead above the minimum detection limit. Many of the soil samples reported TPH and lead concentrations in excess of the applicable Method 1 RA standards. Soil samples from soil borings B-28 and B-32 exceeded the UCL of 10,000 ppm for TPH. The results of TPH and total lead analyses are summarized in Table VII in Appendix B. VOCs were detected at concentrations greater than the minimum detection limits. Dissolved PPM13 were detected at concentrations greater than the minimum detection limits. Dissolved lead in the sample from monitoring well MW-1 was found to exceed the Method 1 RA standard for GW-3 classified groundwater.

Elevated headspace VOCs were reported in soil samples from borings B-1l and B-12 from the May 1996 investigation. Borings B-18 and B-20 exhibited elevated headspace VOCs during the April 1997 investigation. The highest headspace VOC concentration was detected in the soil sample from B-18 at a depth of 7 to 8 feet. The laboratory analyses of soil samples reported detectable concentrations of TPH, PAHs, EPHs, lead and beryllium exceeding applicable Method 1 RA standards in several soil samples. Concentrations of TPH and lead exceeded the Upper Concentration Limits (UCLs) in several soil samples.

According to the 1983 Bedrock Geologic Map of Massachusetts, the bedrock beneath the Site is classified as Roxbury conglomerate, which consists of conglomerate sandstone, siltstone, argillite, and melaphyre. Roxbury Conglomerate is located within the Milford-Dedham Bedrock Zone. A known or estimated depth to bedrock at the Site was unable to be determined. No bedrock outcrops were observed at the Site or in the immediate vicinity. Soils encountered during the CDW investigations were primarily fill material, silt, and clay. The fill consisted of loose, brown, fine to coarse grained sand, and the clay was compact, plastic, and green-gray in color. Fill, including brick and wood, was observed down to depths of approximately 8 feet in most borings. Groundwater was observed during drilling between approximately 3.5 and 9.5 feet below grade. Consolidated bedrock was not encountered during any on-site drilling. Based on the results of the in-situ permeability test, the permeability of the overburden was found to be approximately 0.126 feet/day. The predominant groundwater flow in the overburden is to the south/southeast.

The closest surface water body to the Site is the Muddy River, which is located approximately 0.9 miles to the northwest. The Fort Point Channel is located approximately 1 mile northeast of the Site. According to the Flood Insurance Rate Map for the vicinity, the Site is located within a Zone C floodplain, which is classified as an area of minimal flooding. Stormwater drainage from the Site flows into storm drains located on the subject property and on Northampton Street, Washington Street, Reed Street, and East Lenox Street.

PHASE II-COMPREHENSIVE SITE ASSESSMENT AND PHASE III - IDENTIFICATION, EVALUATION, AND SELECTION OF COMPREHENSIVE REMEDIAL ACTION ALTERNATIVES GRANT MANOR 1820-1850 WASHINGTON STREET, 80-90 & 100-110 NORTHAMPTON STREET, 20 EAST LENOX STREET, 5-15 & 21-27 REED STREET, ROXBURY, MA, DEP Release Tracking Number 3-14171, CDW Project # 579.00 (February 25, 2000).

"1673-1675 Washington Street is improved with a 5,000 square-foot mixed use building constructed in at least the 1880s. 1677-1679 Washington Street is improved with a 5,200 square-foot mixed-use building constructed in at least the 1880s. 7 Worcester Street is improved with a 4,416 square foot mixed-use building constructed in at least the 1880s. The buildings share a common basement and ground floor, which are configured for commercial use, with the upper floors configured for residential use. Historically, the property was unimproved prior to at least the 1880s.

Historically, the ground floor was occupied by commercial use tenants in possession, including Andy’s Cleaners, from at least the 1890s to 2022. In recent years Andy’s Cleaners operated as a drop-off and pickup location, with no on-site dry cleaning. However, on-site dry-cleaning took place on the property in the past. The property was unoccupied prior to at least the 1880s.

Borings logs generally describe overburden from approximately 0.0’ to 4.0’ below ground surface (bgs) as brown and dark brown sand and gravel with cobbles. Soil below 4.0’ below ground surface is characterized as a dense brown clay formation. A groundwater stadia survey was completed by Arcadia Technology in May 2022. Survey data revealed west to northwest hydraulic gradient; although the data was considered somewhat uncertain due to the potential for a perched groundwater table over clay in the area.

Field observations were conducted throughout the assessment activities. Observations indicate that on the exterior of the building sand and silt with some gravel extends from surface grade to depths of approximately 5 feet bsg. Below the sand and silt was a layer of brown to grey clay that extended to greater than 15 bsg. In the interior beneath the basement floor clay was observed to depth of greater than 3 ft. bsg. Groundwater was observed at approximately 4-5 bsg in the exterior monitoring wells. The groundwater was very slow to recharge. Groundwater maybe a perched groundwater table overlying the dense clay layer. Evaluation of the groundwater elevation data indicates groundwater flow is to the west. However, this data is subject to some uncertainty due to potential variable nature of a perched groundwater table.

Laboratory analysis for VOCs, was performed on the 12 soil samples from ATB-4 to ATB-13. The results of the laboratory analysis of the soils samples detected five volatile organic compounds(VOCs) likely related to PCE release. The six compounds were 1,1-Dichloroethene, trans-1,2-Dichloroethene, cis-1,2-Dichloroethene, Trichloroethene(TCE) and Tetrachloroethene(also known as perchloroethylene-PCE) and Vinyl Chloride. The presence of 1,1-Dichloroethene, trans-1,2-Dichloroethene, cis-1,2-Dichloroethene, Trichloroethene(TCE) and Vinyl Chloride likely due to the biodegradation of the PCE.

"Borings logs generally describe overburden from approximately 0.0’ to 4.0’ below ground surface (bgs) as brown and dark brown sand and gravel with cobbles. Soil below 4.0’ bgs is characterized as a dense brown clay formation. See Appendix F for details.

Phase I Initial Site Investigation & Tier Classification, 1673 - 1679 Washington Street, Boston, Massachusetts, MADEP RTN 3-37089, Ardent file ECLP-1615 (October 06, 2022)

South End houses tilting , sagging. Building Commissioner O Hearn; old Roxbury along side of old Boston Neck . Northhampton and Fellows – Harrison to orange, completely unpredictable distances and form. Foundations are not secure if constructed on gravel, ordinary clay, ashes, peat, or broken stone. Bedrock must be located or there will be serious trouble sooner or later. Buildings erected in sand. “the South End filling, according to city engineers, was never properly done. The land is low at the South Bay and gradually rises to Shawmut ave, then recedes to the railroad track. The higher ends of the sewer system found the land the lowest and this led to the unforuatley experiences that the propery owners have passed through for forty years in the matter of sewers. In all the alleyways fo the S End district the sewer pieps are below the streets and the yards are lower than the alleys and many of the cellars. Heavy rain and heavy tide water at the same time have worked havoc with cellor kitchens and dining rooms, the sewers being unable to carry off the surplus flowage until the new sewers were built within two years and heavy pumps installed. This condition has undoublabe operated to a great extend in undermining the foundations of the South End buildings now being complainedof through there wouldahve been no undermining had the builders of these structures insisting on observing the first prinple in building.” How was it possible for these structures to be built? This is a question that is gently asked. There is but one answer. In those days builders were not obligated to present every stage of the building process to the building inspector. There were few laws to cover such ops and those were of most leemnary character.”
Boston Evening Transcript Wed, Jul 14, 1915 ·Page 18

Groundwater was encountered on the property from approximately 5.3’ to 26.5’ below ground surface (bgs). A review Figure 5 of the 1977 United States Geological Survey (USGS) Topographic map reveals topography in the property vicinity gently slopes from the southwest to the northwest direction. The Charles River is located to the northwest. Therefore, based upon topographic and surface water features, groundwater in the property vicinity likely flows from the southeast to the northwest and discharges into the Charles River. See Appendix G for details. A groundwater stadia survey was completed by Arcadia Technology in May 2022. Survey data revealed west to northwest hydraulic gradient; although, the data was considered somewhat uncertain due to the potential for a perched groundwater table over clay in the area. See Appendix D for details. A review of Table 3 reveals that overburden aquifer groundwater monitoring well riser elevations were surveyed during field activities utilizing differential leveling in conjunction with an arbitrary 100’ datum in December 2022. Calculations completed utilizing December 2022 gauging data revealed a horizontal hydraulic gradient vector of approximately -42°, or northwest. This data generally agrees with the inferred groundwater gradient based on topographic features. See Appendix G for details.

Method 3 Risk Characterization and Permanent Solution With Conditions Statement 1673 - 1679 Washington Street Boston, Massachusetts 02118 MADEP RTN 3-37089 Ardent File ECLP-1615 (June 05, 2023)

Environmental Due Diligence activities completed at the property revealed concentrations of Tetrachloroethylene (PCE) and Trichloroethylene (TCE) in sub-slab soil gas exceeding applicable MADEP Residential Threshold Values and concentrations of cis-1,2-Dichlorethene in soil exceeding applicable MADEP Reporting Concentrations. These detections met the definition of a Substantial Release Migration and a 72-hour Reporting Condition. The Release was reported to the MADEP by Arcadia Technology in September 2021. Release Tracking Number (RTN) 3-37089 was assigned. A Notice of Responsibility establishing an Interim Deadline for assessment only Immediate Response Actions was issued by the MADEP in November 2021.

A Notice of Audit Request for Site Inspection was issued to the Responsible Party by MADEP in October 2023. Following audit activities, it was determined that a Condition of Substantial Release Migration (SRM) constituting a 72-hour Reporting Condition existed at the Disposal Site. The SRM Condition was due to previous detections of Trichloroethylene (TCE) and cis-1,2 Dichloroethylene (CIS-1,2-DCE) that exceeded GW-2 standards in groundwater samples collected from a monitoring well (203-MW) located within 30 feet of residentially occupied buildings. The SRM Condition was reported to MADEP on November 07, 2023. Release Tracking Number (RTN) 3-38464 was assigned. Immediate Response Actions including groundwater and indoor air sampling and analyses were verbally approved by MADEP. Assessment activities, including groundwater, sub-slab soil vapor, and indoor air sampling and analyses, were completed in November – December 2023 and summarized in the January 2024 Immediate Response Action Plan filed with MADEP. Assessment activities revealed that a Vapor Intrusion Pathway existed in the basement and ground floor of the adjoining residential condominium at 9 – 11 Worcester Street. A Preliminary Human Health Risk assessment utilizing this data revealed a Long-Term Risk to human receptors at the property.

Groundwater from MW-203, located nearest to the occupied residential dwelling at 9-11 Worcester Street, was historically sampled 3 times over the course of assessment activities conducted at 1679 Washington Street under RTN 3-37089 from September 2022 to March 2023. These sampling events revealed detectable concentrations of PCE, TCE, cis1,2 DCE, and VC. Exposure Point Concentrations for 203-MW were developed by averaging concentrations across the three events. Only the EPC for cis 1,2 DCE exceeded applicable Method 1 Standards (55.83 ug/L, Method 1 GW2 = 20 ug/L). Additional sampling after the issuance of the NOR for the subject RTN 3-38464 was completed in November 2023, April 2024, and September 2024. These events revealed detectable concentrations of site COCs in groundwater, with the concentration of cis 1,2 DCE exceeding applicable Method 1 Standards in April 2024 (44ug/L).

A new downgradient groundwater monitoring well, 601-MW, was installed at the intersection of Worcester Street and Deacon Street, northwest of the Disposal Site on September 12, 2024. Additional cross-gradient wells located southeast and northwest of 601-MW were proposed; however, the driller determined that the density of utilities in the street as indicated by DigSafe markings precluded the advancement of wells in these
locations. Manways and sewer grates near to these proposed locations were screened for VOCs utilizing a PID. No detectable concentrations of VOCs were detected in these utilities. Soil and groundwater from 601-MW were sampled on 9/12/24 and analyzed for VOCs. No detectable analyte concentrations were identified in either medium. Groundwater from 203-MW and 601-MW has been sampled quarterly since the September 2024 event. See Table 7 in Appendix A for a summary of historic groundwater concentrations through the most recent event.

Indoor Air samples collected from the basement and first floor of the 9-11 Worcester Street Condominium unit in December 2023 revealed detectable concentrations of two Volatile Organic Compounds (VOCs) that had been identified as Contaminants of Concern at the adjoining 1679 Washington Street Release site: Trichloroethylene (TCE, 4.3 ug/m3) and Perchloroethylene (PCE, 25 ug/m3). A sub-slab soil vapor sample collected in the condominium basement also revealed a detection of Perchloroethylene PCE, 24 ug/m3).

Immediate Response Action Status, 1673 - 1679 Washington Street & 7-15 Worcester Street, Boston, Massachusetts, MADEP RTN 3-37089, Ardent File ECLP-1615 & ESCP-0426, (November 20, 2025)

SOUTH COVE/NW OF FORT POINT

The area surrounding the Site is composed primarily of mixed industrial, commercial, and residential use. The Site abuts a Vicinity Energy (formerly Veolia) steam generation plant and Kneeland Street to the north, Lincoln Street, beyond which is Parcel 25 to the west, and Atlantic Avenue, beyond which is the South Station railway and bus terminals to the east. The Site abuts an undeveloped parcel (Parcel 27A) to the south. Parcel 27A is the location of capped disposal area for asbestos-containing materials (ACM) generated during the construction of the Central Artery Tunnel (CA/T) project. The location of abutting properties is shown in Figure 2
Lead-impacted soil with concentrations up to 13,000 mg/kg is present on a portion of Parcel 26B, south of the Vicinity steam plant. Soil with elevated concentrations (i.e., greater than 1,000 mg/kg) are primarily associated with shallow soil, 0-5 ft below the pavement that corresponds with undocumented historic fill, which may have been placed to fill former building foundations in this area. • AIS is present in shallow soil (top 3 ft) in select landscape areas located on Parcels 26A and 26B

The Site is relatively flat, sloping gently from north to south. As described in Section 1.0, most of the Site is paved, except for landscaped areas in the parking lot and around Reggie Wong Memorial Park. Given current conditions, most stormwater that falls on the Site is collected into on-site stormwater conveyance structures and either discharges off-site to the City of Boston’s collection system or is recharged on-site through various infiltration swales or tree filters located in the parking lot landscape areas.
Based on the subsurface investigation activities conducted to date, surficial geology at the Site consists primarily of three geologic units. The upper unit is representative of historic fill materials and consists of brown, fine to coarse sand and gravel, intermixed with occasional cobbles and debris including concrete, brick, wood, metals, and ceramic. In several areas, including immediately south of the Vicinity steam plant, large amounts of debris, coal and partially intact brick foundations were also apparent. This fill unit is approximately 10-15 feet thick across the Site. The fill is underlain by a native silty sand with trace organics (peat) between 10 and 15 ft. bgs. These silty sands are underlain by a silty clay containing shell fragments, observed to a depth of up to 40 ft. bgs. Geologic cross-sections for the Site are depicted in Figures 7a and 7b. Bedrock has not been encountered during field activities completed to date. Groundwater was encountered between 5 and 11 ft. bgs.

As shown in Figures 8a and 8b, groundwater at the Site appears to flow to the south-southeast. Using the data from the June and November 2017 monitoring events, an average horizontal gradient for groundwater was calculated for the Site. In general, depth-to-groundwater measurements were consistent with historical groundwater elevations observed in April, May, and November of 2016. Literature values for similar geologic materials were used to estimate the hydraulic conductivity (Kw) and effective porosity (n) for the predominant geologic units at the Site. The hydraulic conductivity value for the fill and silty sand units was estimated to be 5.7 feet/day, while the conductivity for silty clay unit was estimated to be 0.06 feet/day (Domenico and Schwartz, 1990). The estimated effective porosity value for the fill and silty sand units was 0.25 and the estimated effective porosity value for the silty clay unit was 0.20 (Bonazountas and Wagner, 1984)
Groundwater ranges between approximately 5 and 11 feet bgs and flows in a general south, southeast direction towards the Fort Point Channel, which is located approximately 800 feet to the east.

July 2020 Phase II Comprehensive Site Assessment & Phase III Remedial Action Plan MassDOT Parcels 26A & 26B 185 Kneeland Street Boston, Massachusetts RTN 3-33787

6.1.1 Asbestos in Soil AIS has been identified in various paved parking and unpaved landscaped areas in shallow (i.e., less than 3-ft) and deep samples up to 15 feet bgs. Soil sampling results indicate the AIS is present as traces of 1 to 4 fibers where detected; no suspect asbestos-containing materials (ACM) or wastes have been identified. Given the frequency of occurrence, the AIS source is believed to be due to non-point sources and/or potential emissions and/or historical fill. Due to the heterogeneous nature of the fill, AIS impacts are not uniformly distributed.
AIS is present as fibers; no known or suspected ACM or asbestos wastes has been identified. Given the nature and extent of AIS impacts, the source is believed to be believed to be due to non-point sources and/or potential emissions and/or historical fill. Due to the heterogeneous nature of the fill.
Due to the historical observation of asbestos, 56 soil samples were collected and analyzed for the presence of asbestos. Table E.5 presents the asbestos analysis. Twenty-eight soil samples (both surficial and subsurface) contained at least one asbestos fiber. The presence of asbestos fibers in soil is considered by DEP to be a potential human health risk, and this contaminant will be addressed in the Phase III.

6.1.2 Lead Lead has been detected in samples collected from 1 to 15 ft bgs. In general, lead concentrations across most of the Site are less than 1,000 mg/kg, except for in the localized area near SB-110 where concentrations up to 13,000 mg/kg has been identified. Within this localized area, lead impacts correspond with undocumented fill containing a larger amount of debris as well as coal that appears to be confined to 2 to 5 ft below the exiting pavement within an estimated 1,400 square foot area coinciding with several buried foundations. Based on the magnitude and frequency of detections, lead impacts outside the localized area around SB-110 are indicative of anthropogenic fill commonly identified in urban areas subjected to previous development.
Sampling conducted to date has identified various MCP-14 metals, with arsenic in one sample and lead in 16 samples detected above their respective Method 1 S-1 standards. The source of these metals is attributed to undocumented historic fill. Within the localized area of elevated lead concentrations, fill is characterized by greater amounts of debris and coal, which coincide with several former foundations observed in this area
Groundwater sampling identified lead and arsenic in groundwater. Where detected, metals in groundwater coincide with the localized area of elevated lead in soil. Based on the limited extent, the source for metals in groundwater is believed to be historic fill identified within this area, which is also responsible for the soil impacts.
Lead was detected in all 61 samples at concentrations ranging from 8.3 to 13,000 mg/kg. Elevated lead concentrations were identified at location SB-110 which was designated a hotspot area. Hotspot samples (with lead concentrations) include SB-110 (1 to 5 feet, 5,200 mg/kg), SB-110-S (0 to 5 feet, 2,200 mg/kg), and SB-110W (0 to 5 feet, 13,000 mg/kg). Pre-characterization samples were collected in the area of the hotspot to determine the appropriate amount of soil required to remediate the hotspot. It is anticipated that the area outside of the hotspot area that will remain once the hotspot area is excavated and removed will include the following soil samples: SB-110-E (0 - 5', 1100 mg/kg), SB-01 (5-6', 1200 mg/kg), SB-02 (2-5', 1100 mg/kg), and SB-06 (0-5', 1500 mg/kg).
Dissolved arsenic and lead were detected in groundwater. Arsenic was detected in groundwater at timeweight average concentrations ranging from 0.3 to 15 ug/L. Concentrations of arsenic are less than Method 1 GW-3 groundwater standards. Lead was detected in groundwater at 3 of 11 monitoring wells at concentrations ranging from 2 to 14 ug/L. The maximum time-weighted average concentration of lead, detected in monitoring well MW-3, is greater than the Method 1 GW-3 groundwater standard of 10 ug/L. Monitoring well MW-3 is located in the center of the Site

6.1.3 Petroleum Hydrocarbons & PAHs Soil containing petroleum and PAHs has been identified across the Site. Like lead impact to soil, the ubiquitous detection of low-level PAH and EPH/VPH fractions in soil across the Site is attributed to undocumented historic fill. There are also localized areas of petroleum and/or PAH-impacted soil exceeding Method 1 S-1 standards located near SB-109 and SB-110, south of the Vicinity steam plant and at the northern end of the parking lot on Parcel 26B, near SB-119 and SB-120. The source for PAHimpacts near SB-119 and SB-120 is unknown but may be attributed to asphalt/coal intermixed with fill materials. Based on the shallow depth of impacts and presence of coal tar odors, the PAH and petroleum impacts south of the Vicinity building are attributed to residual impacts from historic MGP/industrial operations at the Site.
PAHs and petroleum impacts to soil across most of the Site appear related to the undocumented fill materials, except for the localized area south of the Vicinity steam plant. South of the Vicinity steam plant, PAHs and TPH detections are believed to be related to historic MGP/industrial operations at the Site. As noted previously, based on the shallow depth of impacts and apparent coal tar odors, PAH and TPH impacts are not believed to be associated with any former release or the current bulk petroleum storage below the adjacent Vicinity property.
PAHs – PAHs in groundwater coincide with the localized area of PAH-impacted soil located south of the Vicinity steam plant. The source is attributed to former MGP/industrial operations, which have also resulted in the NAPL droplets observed at select boring locations. Where observed, NAPL appears to be residual. Given the persistent detection of PAHs observed in groundwater samples from the area, residual NAPL may be a continual source; however, the localized extent of these groundwater impacts suggests the source is controlled. Downgradient PAH concentrations in groundwater are below applicable Method 1 GW-2/GW-3 standards.
EPH fractions were detected at total EPH concentrations ranging from 13 to 1,281 mg/kg. The highest detected concentration of EPH fractions was located at soil sample SB-5 (10 to 15 ft. bgs). EPH fractions generally had higher concentrations at depth than in surface soil. Total PAHs were detected in up to 34 of 50 soil samples, with concentrations ranging from 0.14 to 490 mg/kg. PAHs were detected in the greatest concentrations in soil samples SB-120 (5 to 10 feet) and SB119 (5 to 10 feet).

July 2020 Phase II Comprehensive Site Assessment & Phase III Remedial Action Plan MassDOT Parcels 26A & 26B 185 Kneeland Street Boston, Massachusetts RTN 3-33787

8.2.5 Identification of Background Conditions Background conditions are defined in the MCP (310 CMR 40.0006) as those levels of OHM that would exist in the absence of the disposal site of concern, which are either: a) ubiquitous and consistently present in the environment at and in the vicinity of concern, and attributable to geologic or ecological conditions, or atmospheric deposition of industrial process or engine emissions; b) attributable to coal or wood ash associated with fill material; c) releases to groundwater from a public water supply system; or d) petroleum residues that are incidental to the normal operation of motor vehicles

As presented on Table E.8, the maximum concentrations of PAHs and metals (excluding hotspots) were compared to background concentrations in natural soil. PAHs were greater than the published background concentrations and were retained as constituents of potential concern (COPC). For metals, the maximum concentrations of arsenic and cadmium were less than background concentrations and were eliminated as COPC. The other metals were retained as COPC in this Risk Characterization.

CONCEPTUAL SITE MODEL The subsurface investigations performed at the Site to date were used to develop a Conceptual Site Model (CSM) which summarizes the contaminant sources and distributions, impacted media, release mechanisms, exposure pathways, migration routes, and potential receptors. The Site consists of two parcels, totaling approximately 3 acres, that are located on Kneeland Street in Boston, Massachusetts. The Site is developed and currently occupied by a 10-story office building, a paved parking lot, and various landscape areas. A portion of the Site is also occupied by the Reggie Wong Memorial Park. Historically, the Site had various industrial/commercial uses, storage of gasoline (filing station), railroad operations, transportation trucking companies, warehousing, leather working, and professional office space/parking. A portion of Parcel 26B was also reportedly occupied by a manufactured gas plant (MGP) that supported nearby railroad operations. As described in Section 5.0, topography across the Site is generally flat. Surficial geology consists of undocumented fill materials, which are underlain by native silty sand and silty clay. Fill materials have been observed up to 15 ft bgs and include fine to coarse sand and gravel intermixed with occasional cobbles and debris, such as concrete, brick, wood, metal, asphalt and ceramic. There is also a localized area near SB-110, south of the Vicinity building, where the fill is characterized by the presence of coal and the remnants of several former building foundations. Bedrock has not been encountered at the Site. Shallow overburden groundwater is detected between 5 and 11 ft bgs and flows across the Site in general south-southeast direction as shown in Figures 8A and 8B. Potential sources of contamination, including historic commercial/industrial land uses, were investigated through preliminary response actions and the Phase II CSA activities. Based on the results, soil across the Site has been impacted by AIS, metals (primarily lead), PAHs and/or petroleum hydrocarbons. Groundwater within a localized area on Parcel 26B is also impacted by lead and PAHs. As described in Section 6.0, AIS has been detected in shallow (i.e. less than 3 ft) and deep (up to 15 ft) samples from paved and unpaved areas across the Site. The AIS is present as fibers; no suspect ACM or asbestos waste has been identified. Based on the nature and extent, the AIS is believed to be from non-point sources, potential emissions, and/or historical fill. Throughout the Site, lead is present in soil at concentrations typical of “urban” fill, mostly below the applicable Method 1 S-1 standard (200 mg/kg). However, there is a localized area of elevated lead concentrations near SB-110 that are not consistent with those identified in “urban” fill at comparable sites. Within this area, lead concentrations up to 13,000 mg/kg have been identified. The elevated concentrations are believed to be associated with a localized area of fill containing more debris as well as coal, which was encountered between 2 to 5 ft bgs in an approximately 1,400 square foot area. As summarized in Section 6.0, soil containing PAHs and petroleum hydrocarbons have been detected across the Site. Where detected, concentrations are generally below their applicable Method 1 S-1 standards, except within two localized areas. South of the Vicinity steam plant, the PAH and TPH impacts are believed to be related to historic MGP/industrial operations. At northern end of parking lot on Parcel 26B, near SB-119 and SB-120, the source for elevated PAHs is unknown; however, it may be attributed to asphalt identified within the historic fill identified at the Site. Outside these localized areas, PAH and petroleum detections are attributed to undocumented historic fill. Figure 6 illustrates the approximate limits of a localized area of PAH and lead impacted groundwater at the Site. As shown, the area is confined to south of the Vicinity steam plant. The source of these impacts is believed to be historic MGP/industrial operations. These historic operations are also believed to be responsible for the residual NAPL droplets encountered at select boring locations from 10 to 25 ft bgs.

July 2020 Phase II Comprehensive Site Assessment & Phase III Remedial Action Plan MassDOT Parcels 26A & 26B 185 Kneeland Street Boston, Massachusetts RTN 3-33787

SB-110S: "tight, sulfurous and petroleum like odor"

SB-110W SB-110W SB110W: 7'6"-10' bgs: Brown PEAT/ROOTs, sulfurous odor, tight

SB110N: 7'-8' bgs: Black fine to medium SAND, little gravel, sheen, strong coal tar like odor

SB110E: 9-10' bgs: Brown PEAT/ROOTS, "sulfurous odor/coal-tar-like odor."

DORCHESTER AVE / MASS AVE / SOUTHHAMPTON / SOUTH BOSTON

The Site is currently utilized as a self-storage facility. Based on a review of available historical documents, the Site was previously utilized as a cold storage facility from 1963 until 2000. Prior to 1963, the southern portion of the Site was occupied by a fuel oil and gasoline filling station since at least 1930. Based upon a review of Sanborn Fire Insurance Maps, eleven (11) gasoline and fuel oil underground storage tanks (USTs) were associated with the filling station. There is no documentation confirming removal of the on-Site USTs, however due to the presence of a basement in the area of the eleven USTs, their removal likely coincided with the construction date of the Site building in 1963. In addition, an electromagnetic (EM) and ground penetrating radar (GPR) survey was supervised by ATC to determine whether underground storage tanks were present in the northern portion of the Site in the vicinity of the former filling station. The EM/GPR survey did not identify USTs in the northemrn portion of the Site.

ENSR Consulting and Engineering (ENSR) of Acton, Massachusetts conducted a Phase I ESA at the Site in October 1999. At the time of their Site reconnaissance, the Site was occupied by Atlantic Cold Storage, which utilized the Site for frozen food storage. Based upon a review of historical documentation, ENSR indicated that the former use of the Site as a filling station with eleven (11) associated fuel oil USTs posed a material threat of release to the Site. Additionally, ENSR indicated the former use of surrounding properties as a filling station and a rail yard posed a material threat of release. In November 1999, ENSR conducted a subsurface investigation at the Site to address on and offSite issues identified in the October 1999 Phase I ESA. A total of seven (7) soil borings (B-1 through B-5 and S-1 and S-2) were advanced inside the building and in the northern portion of the Site. The three (3) exterior borings were completed as monitoring wells (MW-1 through MW-3). The soil samples collected from MW-2 contained naphthalene at a concentration of 4.9 parts per million (ppm), C9-C18 aliphatic hydrocarbons at a concentration of 1,500 ppm, and C11- C22 aromatic hydrocarbons at a concentration of 790 ppm, all of which were above applicable MCP RCS-1 reportable concentrations. Soil samples from MW-3 contained concentrations of C9-C10 aliphatic hydrocarbons at 140 ppm and C11-C22 aromatic hydrocarbons at 300 ppm, which were also above the RCS-1 reportable concentrations. In addition, soil collected from S-1 contained C11-C22 aromatic hydrocarbons at a concentration of 240 ppm, above the applicable reportable concentration. Volatile petroleum hydrocarbons (VPH) and extractible petroleum hydrocarbons (EPH) were detected at concentrations below RCS-I reportable concentrations in all other soil samples...The laboratory data from ATC's investigation reported EPH, VPH, naphthalene, 2- methylnapthalene, arsenic, barium, lead and mercury in site soils above the RCS-1 reportable concentrations. In addition, the laboratory reported CQ-C 8 aliphatic hydrocarbons in groundwater collected from ATC-1 and ATC-2 above the RCGW-2 reportable concentration.
The ESA identified that the Site was formerly utilized as a filling station with ebven (11) fuel oil and gasoline underground storage tanks associated with the operation. Additionally, at least one gasoline UST was associated with a filling station and automobile sales business which operated on the northern portion of the Site and the north abutting property. A letter identified in the City of Boston Fire Prevention files indicated that licenses were issued for the underground storage of 99,000 gallons of fuel oil and 20,550 gallons of gasoline at the Site. There is no documentation confirming removal of the on-Site USTs; however due to the presence of a basement in the area of the eleven USTs, their removal likely coincided with the construction date of the Site building in 1963.

CLASS A-3 RESPONSE ACTION OUTCOME STATEMENT AND ACTIVITY AND USE LIMITATION DEVON SELF STORAGE 968 Massachusetts Avenue Boston, Massachusetts 02118 RTN 3-21483 JULY 9, 2002

The work was conducted pursuant to the Massachusetts Contingency Plan (MCP) in 310 CMR 40.0000 in response to a 120-day reporting condition under the MCP. The site contains Release Tracking Number (RTN) 3-20652, and consists of the entire property at 290 Southampton Street. Figure 1 (Site Locus) depicts the site location, and Figure 2 (Site Plan) shows the site. The site at 290 Southampton Street is approximately 32,550 square-feet in size. The Universal Transverse Mercator (UTM) coordinates for the site are north 468834 and east 329911. A Locus Map and a Site Map, depicting pertinent site features, are attached as Figures 1 and 2, respectively. Based on historical records reviewed as part of the Phase I, the subject property was utilized as a NY, NH & H Railroad Locomotive Repair facility from approximately 1920 to at least 1950 (the date of the oldest available Sanbomrn Fire Insurance Map which depicted locomotive repair activities at the subject site). The exact date that locomotive repair activities ceased at the property could not be ascertained; however, the next available Sanbomrn Fire Insurance Map for the subject site, dated 1964, illustrated the subject site as vacant land. Municipal records reviewed as part of the Phase I indicated that in June 1976, the subject property received a permit to install two 10,000-gallon gasoline underground storage tanks (USTs) and three 10,000-gallon diesel USTs for retail sale. According to a map reviewed at the Boston Building Department from the early 1980s, gas pumps were located to the west of the site building. No additional information was available concerning these tanks from the Boston municipal offices. As discussed in the next section, their potential presence was investigated with a geophysical survey. The subject property's current site building was constructed in approximately 1985. The building has been used as an automotive tire service center since it was constructed in 1985. The subject property is developed with the aforementioned tire service center (Boston Tire Service), a mobile office trailer and tire storage trailers. The subject property is used as a tire retail and service center which replaces old tires on cars and trucks with new or used tires. The tire service building is situated in the center of the subject property and surrounded to the north, east and west by unpaved land and to the south by paved land. The tire service building, which is constructed slab on grade, contains two service bays located in the westem portion of the building; a central, covered tire storage area; and, a boiler room, restroom and storage room located in the eastern portion of the building. The mobile office trailer is located along the southwestern border of the subject property.

Groundwater was encountered in borings GP-1 through GP-6 at a depth of approximately 12 feet below surface grade. This is consistent with the estimated depth to water at the site based on a review of the Boston South USGS topographic map (estimated to be 10 to 15 feet below the ground surface). In addition, the geotechnical report referenced above notes the depth of groundwater being between 12 and 15 feet below the ground surface. Based on the Boston South Topographic Map, groundwater in the area of the subject property is expected to flow to the east-southeast towards Old Harbor, located approximately 4,000 feet southeast of the subject property. No surface water bodies are present on the subject property. However, as previously mentioned and according to the report by Geotechnical Consultants, Inc., the Dorchester Creek is culverted through the western portion of the subject property. Old Harbor is situated approximately 4,000 feet to the east-southeast (Figure 1). No wetlands were observed on the subject property, and the MassGIS DEP Site Scoring Map (Figure 3) indicates that no wetlands are located within a 1-mile radius of the site. The USGS Boston South, Massachusetts Quadrangle Map indicates that the site is situated approximately 15 feet above mean sea level, with a prevailing land slope toward the Old Harbor. The site does not lie within a flood zone.

Background concentrations are the levels of OHM that would exist in the absence of the disposal site, and are ubiquitous and consistently present in the environment and in the vicinity of the site. Sources of background concentrations include geologic or ecological conditions, atmospheric deposition of industrial process or engine emissions, fill material containing wood or coal ash, or petroleum residues incidental to the normal operation of motor vehicles. Significant quantities of coal and coal ash fragments were encountered throughout the first six feet of fill material in borings GP-7 through GP-12, and similar fill material extends deeper and throughout the site. The PAHs detected in soil above RCS-2 levels include 5 PAHs in two samples, and 4 of the same 5 PAHs in one sample. In ENSR's opinion, the PAHs detected in the borings are likely related to the presence of coal in the fill material. The opinion is supported by the following: 1) low concentrations of naphthalene were detected in four of the six soil samples and low concentrations of 2-methylnapthalene were detected in only one of the six soil samples (the two predominant PAH fractions in fuel oil), while concentrations of PAHs were detected in five of the six soil samples; 2) No VPH fractions and only low concentrations of C11-C22 aromatic hydrocarbons and/or C19-C26 aliphatic hydrocarbons were detected in three of the soil samples; 3) no VPH or EPH levels were detected in the groundwater samples; and, 4) the distribution of detected PAHs (including naphthalene and 2-methylnapthalene) do not correspond with the detected C11-C22 aromatic hydrocarbons and/or C19-C26 aliphatic hydrocarbons in the soil samples to reveal a single source, but rather a placement of fill material across the site. Based on an inspection of the soil borings, it appears as if fill material which contained coal was used to grade the subject property for development purposes. Therefore, in ENSR's opinion, the presence of PAHs at the subject property are representative of background conditions, and were exempt from the reporting requirement under the MCP 310 CMR 40.0317(9) and (12)(a).
CLASS A-3 RESPONSE ACTION OUTCOME STATEMENT AND ACTIVITY AND USE LIMITATION DEVON SELF STORAGE 968 Massachusetts Avenue Boston, Massachusetts 02118 RTN 3-21483 JULY 9, 2002

MDC Police Headquarters is located at 220-240 Southampton Street, approximately 450 feet westnorthwest of the subject property, and was identified as a DEP confirmed disposal site having Tier II status. According to the information provided, the site was purchased by the MBTA in 1993. On December 17, 1993, a release, defined by the presence of non-aqueous phase liquid (NAPL), was reported to the DEP, and RTN 3-10315 was assigned by the DEP. A RNF was subsequently filed by the MTBA indicating that reportable conditions on-site included NAPL on groundwater, lead in soil, total petroleum hydrocarbons (TPH) in soil, and six PAHs in soil. In June 2000, an AUL was filed for this property with the DEP. The AUL area consisted of the entire property, approximately 3.5 acres. A MCP AUL Opinion Report was completed which was intended to be part of the information supporting a Class A-3 RAO. A RAO for the site was not included in the DEP files at the time of ENSR's review.

CLASS A-3 RESPONSE ACTION OUTCOME STATEMENT AND ACTIVITY AND USE LIMITATION DEVON SELF STORAGE 968 Massachusetts Avenue Boston, Massachusetts 02118 RTN 3-21483 JULY 9, 2002

GZA reviewed the Massachusetts GIS Priority Resources Map to identify sensitive receptors in the vicinity of the Site (Appendix D). There are no surface water bodies located on the Site or within a 500-foot radius of the Site. Surface water bodies in the vicinity of the Site include Old Harbor, located approximately 4,500 feet to the east of the Site, and Fort Point Channel, located approximately 4,000 feet to the north of the Site (Figure 1). The Site is not located within 500 feet of a current or potential drinking water source area. The Site is not located within ½ mile of a potentially productive aquifer (PPA), Interim Wellhead Protection Area (IWPA), Zone II area or a Zone A surface water body. Potable water for the Site and surrounding area is supplied by the City of Boston. No institutions, as that term is defined in the MCP, were identified within 500 feet of the Site. There are no Estimated Rare Wetland Wildlife Habitats, Areas of Critical Environmental Concern, wetlands, surface water bodies, vernal pools, floodplains or protected open spaces at or within 500 feet of the Site.
Historically, the Site was vacant land until a petroleum/chemical company was located along the Site’s western boundary from the early 1900s to as recently as the early to mid-1950s. Historical maps identified four to five tanks on the Site during this time period. The tanks were identified on the historical maps as “oil” tanks. It appears that the oil storage was likely both above and below ground. Railroad spurs occupied the remainder of the Site. Subsequently, all buildings were razed, and the railroad spurs and tanks were removed. From the 1950s to the mid-1980s, a diner occupied the southeast corner of the Site, and the remainder of the Site was used as a paved parking area. In the mid-1980s, the Site was redeveloped for the occupancy of the Beckwith Elevator Company. The redevelopment included the renovation of the former diner into office space and the construction of a warehouse addition used for the storage of elevator parts. No manufacturing or significant repair activities were reportedly conducted during the Beckwith Elevator Company occupancy. In 2009, the Beckwith Elevator Company vacated the Site. The Site was then occupied by Boston Red Dog Pet Resort and Spa, a kennel and pet supply business, starting in 2010. Adjoining properties have historically been occupied by an electrical substation, food distribution facilities and a meatpacking company.
PERMANENT SOLUTION STATEMENT WITH CONDITIONS 274 Southampton Street Boston, Massachusetts Release Tracking Number 3-33583 June 2017 File No. 01.0170056.20

Offshore

Submarine canyons are the most important conduits for funneling sediment from continents to oceans. Submarine canyons, however, are zones of sediment bypassing, and little sediment accumulates in the canyon until it ceases to be an active conduit. To understand the potential importance in the rock record of any given submarine canyon, it is necessary to understand sediment-transport processes in, as well as knowledge of, deep-sea turbidite and related deposits that moved through the canyons.
Normark, William & Carlson, Paul. (2003). Giant submarine canyons: Is size any clue to their importance in the rock record?. 10.1130/0-8137-2370-1.175.

Uncounted prehistoric and historic archaeological sites lie within the Gerry E. Studds Stellwagen Bank National Marine Sanctuary. Ancient geologic and glacial processes once exposed the sanctuary’s seafloor to the sun, allowing it to support flora and fauna utilized by the Paleo-Indian peoples. Rising sea levels covered the sanctuary within several millennia of its exposure, moving Native American habitation to the shores around Massachusetts Bay. . The area had the potential to support habitation and use of Stellwagen Bank before its inundation of seawater 10,000 years ago. The likelihood is high that human or animal remains might be located in the future. The possibility of finding Paleo-Indian cultural items on Stellwagen Bank is enhanced by the report of the recovery of mastodon skeletal remains by local fishermen. Further geologic study, site modeling, and sampling will be conducted on Stellwagen Bank to determine the potential for locating prehistoric cultural remains in the sanctuary.
https://nmssanctuaries.blob.core.windows.net/sanctuaries-prod/media/archive/library/pdfs/fop.pdf

Submarine canyons are deep, steep-sided valleys eroded into the seafloor along the world’s continental margins. They link terrestrial and deep-marine systems by transferring sediment, organic carbon, and pollutants (1–3). With lengths of up to 400 km and wall heights of up to 5 km, they dwarf their terrestrial counterparts (3). Similar to rivers on land, submarine canyons are key drivers in shaping the seafloor along Earth’s continental margins (4). Acting as conduits between land and the deep ocean, they embody what J. Syvitski termed the “global handshake between the coastline and the abyss.” Solid material transfer along the deeply incised canyons nourishes submarine fans with sediment including organic carbon, nutrients, and litter (3, 5, 6).
To understand what controls submarine canyon occurrence, it is helpful to morphologically categorize submarine canyons into two types: slope-confined (or “blind”) canyons, which are exclusively located on the continental slope, and shelf-incised canyons, whose canyon heads eroded into the shelf (10, 11). Shelf-incised canyons can be further classified as shore-connected if they extend to the coastline, where they link to terrestrial sediment sources, such as river outlets or longshore currents (Fig. 1). However, modern canyons that connect to the shore are rare—only about 4% of all canyon heads (and 11% of shelf-incised canyons) along the world’s major continental margins between 50°N and 50°S (12). Although some slope-confined canyons experience frequent turbidity current activity (13), studies show that shelf-incised canyons intercept river-derived and longshore sediment sources more effectively, making them particularly important conduits for transporting material to the deep ocean floor (2, 5, 7). In addition, they support more species-rich ecosystems compared to slope-confined canyons (9).
Anne Bernhardt, Wolfgang Schwanghart ,Seafloor slopes control submarine canyon distribution: A global analysis.Sci. Adv.11,eadv3942(2025).DOI:10.1126/sciadv.adv3942

NPS Map: Siege of Boston fortifications overlaid on South End, South Boston, and Boston (1775)