United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R01-89/035
June 1989
$EPA
Superfund
Record of Decision
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50272.101
REPORT DOCUMENTATION It. REPOATNO. Iz.
PAGE EPA/ROD/R01-89/035
3. A8c1pIent'a AcC88810n No.
4. TItle and ~
SUPERFUND RECORD OF DECISION
Sullivan's Ledge, MA
First Remedial Action
7. Authar(a)
5. A8part Date
06/28/89
I.
I. P8rfonnlng Organization RepL No.
.. P8rf0nnlng OrgaInIzatIon H8nw and ~
to. ProjactlT88IcIWortI UnIt No.
t t. ContrIIc1(C) Of' Gnnt(G) No.
(C)
(a)
12. Sp-...tng Org8lllZ81lon H8nw and AdIhM
U.S. Environmental Protection
401 M Street, S.W.
Washington, D.C. 20460
13. Type 0' Report . Pttrtoct Covered
Agency
800/000
14.
15. SuppletMntUy No..
'.
. ~.
II. Abatract (Umit: 200 worda)
The Sullivan's Ledge site is a 12-acre disposal area in an urban area of New Bedford,
Massachusetts. The site is bordered by a country club and marsh area to the north and
small businesses to the east and west. The site was operated originally as a granite
quarry and includes four 150 ft deep quarry pits. Between the 1930s and 1970s, the
quarry and adjacent areas were used for disposal of hazardous materials and other
industrial wastes. Site investigations conducted in 1986 and 1988 revealed high
concentrat~ons of PCBs in soil and sediment, and VOCs and inorganics in on-and offsite
ground and surface water. Surface runoff and ground water from the disposal area
discharge into the adjacent stream which drains into the country club golf course and
the Middle Marsh Wetlands area. In addition, a small portion of the site lies within
the stream's lOO-year floodplain. EPA concluded that the sources of contamination are
onsite soils, PCB-contaminated sediments washed offsite and found in an adjacent stream
and wetland areas, and wastes disposed of in the former quarry pits. This ROD
addresses source control and management of migration; a subsequent ROD will address the
Middle Marsh area. The primary contaminants of concern affecting the soil, sediment,
ground water, and surface water are VOCs including benzene and TCE] organics including
PCBs and PARs: and metal including lead.
(See Attached Sheet)
17. D_1 An8Jyai8 L D88cr1pto18
Record of Decision - Sullivan's Ledge, MA
First Remedial Action
Contaminated Media: soil, sediments, gw
Key Contaminants: VOCs (benzene, TCE), organics,
(PCB, PAHs), metals (lead)
b. Identifler8lOpen-EndecI Tenna
c. COSA 11 FIeIdIGroup
18. Availabllty Statement
111. Sec\8ity CI..a (Thia Report)
None
20. Security CI..a (Thla Page)
Non'"
21. No. 01 Pagea
79
I
22. Price
(See ANSl-DII.18)
See IMIrUCIiOM on RIIwIN
2n (4-77
(Fonnerty Nl15-35)
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EPA/ROD/ROl-89/035
Sullivan's Ledge, MA
First Remedial Action
16.
Abstract (Continued)
The selected remedial action for this site includes excavation/dredging of 24,200 yd3
of soil and 1,900 yd3 of sediment with onsite treatment using solidification, followed
by onsite disposal; construction of an II-acre impermeable cap; air monitoring;
diversion and lining of the stream adjacent to site; active ground water pumping and
passive underdrain collection with treatment using oxidation/filtration and
UV/ozonation with offsite disposal of contaminated residuals (ground water disposal.
will be determined after further studies); wetlands restoration/enhancement; sediment,
ground water, and surface water monitoring; institutional controls including ground
water use and access restrictions. The estimated present worth cost is $10,100,000;
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ROD DECISION SUMMARY
SULLIVAN'S LEDGE SUPERFUND SITE
NEW BEDFORD, MASSACHUSETTS
JUNE 28, 1989
U.S. ENVIRO~~ENTAL PROTECTION AGENCY
REGION I
of-
L---- - . .-.-. ...- .,... --.. ~"."~'-
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contents
I.
II.
A.
B.
III.
IV.
V.
A.
B.
C.
D.
E.
F.
G.
H.
VI.
VII.
VIII.
A.
B.
IX.
A.
B.
c.
X.
A.
B.
c.
. . _.~_.. ....'.
sullivan's Le~qe site
TABLE OF CONTENTS
Paqe Number
SITE NA1~E, LOCATION AND DESCRIPTION.
. . . .
SITE HISTORY. . . . . . . . . . . . . . . .
Response History. . . . . . . . . . . . ...
Enforcement History. . . . . . . . . . . . .
COt~1UNITY RELATIONS. .
. . . .
. . . .
. . .
SCOPE A!W ROLE OF OPERABLE UNIT OR RESPONSE
ACTION. . . . . . . . . . . . . . . . . . .
SITE CHARACTERISTICS. . . . . . . . . . . .
General. . . . . . . . . . . . . . . . . . .
Hydrogeology. . . . . . . . . . . . . . . .
Soil. . . . . . . . . . . . . . . . . . . .
Sedi~ents. . . . . . . . . . . . . . . . . .
Quarry pits. . . . . . . . . . . . . . . . .
Groundwater. . . . . . . . . . . . . . . . .
Surface Water. . . . . . . . . . . . . . . .
Biota Investigation. . . . . . . . . . . . .
S~~Y OF SITE RISKS.
. . .
. . .
. . . . .
DOCUI1ENTATION OF SIGNIFICANT CHANGES.
. . .
DEVELOPMENT AND SCREENING OF ALTERNATIVES. .
statutory Requirements/Response Objectives.
Technology and Alternative Development and
screening. . . . . . . . . . . . . . . . . .
DE.sCRIPTI0N/SUMMARY OF THE DETAILED AND
COMPARATIVE ANALYSIS OF ALTERNATIVES. . . .
Source Control (SC) Alternatives Analyzed. .
Management of Migration (MM) Alternatives
Analyzed. . . . . . . . . . . . . . . . . .
Site Alternatives (SA) Analyzed. . . . . . .
THE SELECTED REMEDY. . . . . . . . . . . . .
Description of the Selected Remedy. . . . .
Target Levels. . . . . . . . . . . . . . . .
Rationale for Selection. . . . . . . . . . .
."'. ....__.~.._. ,..--.--..-----'----."'---'..
-..._-- -..
1
2
2
2
3
4
5
5
6
7
7
8
8
10
11
12
18
19
20
21 .
22
22
23
23
30
30
43
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XI. STATUTORY DETERMINATIONS . . . . . . . . . . 51
A. 'The S~lected Rer:.edy is Protective of H~an
Health and the Environment . . . . . . . . . 51
B. The Selected Remedy Attains ARARs. . . . . . 52
,.. -:~. c. ~clected Remedial Action is Cost
.....
Effective. . . . . . . . . . . . . . . . . . 61
D. The Selected Remedy utilizes Permanent
Solutio:"'1s and Alternative Treatment
Technologies or Resource Recovery
Technologies to the Maximum Extent
Practicable. . . . . . . . . . . . . . . . . 62
E. The Selected Remedy satisfies the Preference
for Treatment as a Principal Element . . . . 62
XII. STATE ROLE . . . . . . . . . . . . . . . . . 63
LIST OF FIGURES
Fiqure Nur..ber
Paqe Number
1
2
3
4
5
6
site Location Map. . . . . . . . . . . .
Delineation of 100-year Floodplain. . .
Local Groundwater Flow. . . . . . . . .
Overburden Plume Map. . . .. . . . . . .
Site Preparation Plan. . . . . . . . . .
Locations of Off-Site Soil
Sampling/Sediment Excavation. . . ~ . .
Proposed Cap Design. . . . . . . . . . .
Proposed Areal Extent of Cap. . . . . .
7
8
LIST OF TABLES
Table Number
Paqe Number
1
2
J
List of contaminants of Concern. . . . .
Table of SC and MM Alternatives. . . . .
Table of ARARs . . . . . . . . . . . . .
APPENDICES
Responsiveness Summary. . . . . . . . . . . . .
Administrative Record Index. . . . . . . . . . .
State Concurrence Letter. . . . . . . . . . . . .
. ,
64
65
66
67
68
69
70
71
72
74
76
~
Appendix A
Appendix B
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ROD DECISION SUY~Y
I.
SITE NAME, LOCATION AND DESCRIPTION
S!T~ ~AM~: Sullivan's Ledge
Bl~£ LOCATION: New Bedford, Massachusetts
SITE DESCRIPTION: Sullivan's Ledge, a 12-acre disposal
area, is located on Hatha~ay Road in an urban area of the City of
Ne~ Bedford, Eristol County, in Southeastern Massachusetts. The
disposal area is roughly bounded on the north by Hathaway Road,
on the south by I-State 195/Route 140 Interchange and on the east
and west by commercial development (see Figure 1). Immediately
north of He.thak'ay Road is the Whaling City Country Club, which
covers about 250 acres. Throughout this Record of Decision (ROD)
'the disposal area is referred to as Sullivan's Ledge (SL) or the
Site.
The study area includes the Sullivan's Ledge disposal area and
the country club because contamination migrates from the site via
an unnamed stream to the country club, and contaminated
groundwater also discharges from seeps along Hathaway Road.
Surface ~ater bodies in the study area include the unnamed
strea~, golf course water hazards, Middle Marsh and the
Apponagansett Swamp. The unnamed stream follows a well-defined
channel starting adjacent to the eastern border of the site,
continuing north~ard across the golf course, bisecting Middle
Marsh and eventually draining into t~e golf course water hazards.
Surface runoff, overburden groundwater and shallow bedrock
ground~ater from the disposal area discharge to the unnamed
stream. Esti~ates of flood potential presented by the unnamed
stream were presented in the Phase I RI. The 100-year floodplain
for the site is delineated in Figure 2. This figure shows that
only a s~all portion of the disposal area, at the northeastern
corner, lies within the 100 y~r floodplain.
The 12-acre Sullivan's Ledge disposal area is a former granite
quarry. Four granite quarry pits with estimated depths up to 150
feet have been identified from historical literature and field
investigations. After quarrying operations ceased, the land was
acquired by the City of New Bedford. Between the 1930's and the
1970's the quarry pits and adjacent areas were used for disposal
of hazardous materials and other industrial waste.
A more complete description of the site can be found in the
"Phase I Remedial Investigation Report; June ,1987" in Chapter 1
of Volume I.
II.
SITE HISTORY AND ENFORCEMENT ACTIVITIES
....------------.-..---.... -- -
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2
II.
SITE HISTORY AND ENFORCEMENT ACTIVITIES
A.
Responce History
The United states Environmental Protection Agency (EPA) conducted
an air monitoring program of the Greater New Bedford Area in 1982
and installed ground~ater monitoring wells around the Sullivan's
Ledge site in 1983. Based, in part, on the re~ults of these
studies, the site was included on the National Priorities list in
Septe~~er 1984. The Phase I and Phase II Remedial
Investigations, performed by EPA, were completed in September
1987 and January 1989, respectively. The Feasibility Study was
also co~plet€d in January 1989.
In Septer.~er 1984, EPA issued the owner of the site, the City of
New Bedford, an Administrative Order under Section 106 of the
Cowprehensive Environmental Response, Compensation and Liability
Act of 1980 (CERCLA). In compliance with this Order, the City of
New Bedford in 1984 secured the disposal area by installing a
perimeter fence and posted signs warning against unauthorized
trespassing of the site.
A more detailed description of the site history can be found in
the "Phase I Remedial Investigation Report; J.une 1987" in Chapter
1 of vol ur..e I.
B.
Fnforce~ent History
In September 1984 an Administrative Order was issued to the City
of New Bedford to conduct the activities as outlined in the
preceding Response History section.
On November 29, 1988, EPA notified approximately 15 parties who
either owne~ ~r operated the facility, generated wastes that were
shipp€j to the facility, or transported wastes to the facility,
of their potential liability with respect to the site.
The PRPs have been active in the remedy selection process for
this site. Technical comments presented by the PRPs during the
public comment period were summarized in writing, and the summary
and written responses were included in the Responsiveness Summary
in Appendix A.
Special notice has not been issued in this case to date.
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3
III.
CC~~UNITY RELATIONS
':'~'? ':'.:~l~Y?~'<; !..':c.ge site was originally included as part of the
Ne~ Bedfo~rl H~rbor site, known as the Greater New Bedford
superf~nd site. The level of community concern about the Greater
Ne~ EeJford ~ite ~as quite high during the fall of 1984, when an
opan (,01.1.5-: \ia.s he:ld by EFA to explain cleanup options for PCB
"hot spots," and a public hearing was held to obtain comments
fro~ citizens and local agencies and organizations. About that
sa~e time, the EPA and the Massachusetts Department of Public
Heal th annot~nced the start of a thre:e.-year health study in the
greater New Bedford area that included testing individuals to
deteITIine the level of PCBs in their bloodstream. EPA provided
funding for the study.
other public meetings held to discuss findings or information
ac:.at the l~",,'." redford sites occurred in January and October of
1985. At the October 1985 meeting, the EPA announced the
decision to separate the sullivan's Ledge site from the Greater
New Bedford superfund site and include the Sullivan's Ledge site-
on the National Priorities List (NPL). The decision to create a
separate site ~as based on the following considerations:
1.
The severity of the problem and the environmental
complexity of the Sullivan's Ledge site.
2.
E~vironmental diversity between harbor areas (aquatic)
and the Sullivan's Ledge site (primarily wetlands and
uplands).
3.
Difference in the range of contaminants found.
4.
possible differences in potentially responsible parties
(PRPs) at the sites.
5.
Degree to which separate management would facilitate
activities at the sites.
Throughout the site's more recent history, community involvement
has been moderate. EPA has kept city government officials and
other interested parties informed through informational meetings,
fact sheets, press releases and public meetings.
In September 1986, EPA finalized a community relations plan which
outlined a program to address community concerns and keep
citizens informed about and involved in activities during
remedial activities. On July 20, 1988, EPA held an informational
meeting to present the results of the Remedial Investigation.and
to answer questions from the public.
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4
An administrative record was prepared and made available to the
public on February 6, 1989. On that same date, EPA held an
'::'~'.~;-:.-::.:.tic;-.t.l ;:-.c::":i:.; to discuss the cleanup alter:-;ative£
presented in the Feasibility Study and to present the Agency's
Proposed Plan. From February 6 to March 27, 1989, the Agency
held a forty-nine day public comment period to accept public
co~:.er.t on the alternatives presented in the Feasibility Study
and the Proposed Plan and on other documents available to the
public. On-February 21, 1989, the Agency held a public hearing
to accept oral comments. A transcript of this hearing and the
comments and the Agency's response to comments are included in
the attached responsiveness summary.
IV.
SCOPE AND ROLE OF OPERABLE UNIT OR RESPONSE ACTION
The selected remedy was developed by combining components of
different source control alternatives and a management of
migration alternative to obtain a comprehensive approach for site.
remediation of all portions of the site except for Middle Marsh.
In su~~ary, the remedy consists of nine components:
6.
7.
8.
9.
1.
2.
Site preparation;
'Excavation, solidification and on-site disposal of
contaminated soils;
Excavation, dewatering, solidification and on-site-
disposal of contaminated sediments;
Cons~ruction of an impermeable cap over an 11-acre
area;
Diversion and lining of a portion of the unnamed
stream;
Collection and treatment of contaminated groundwater;
Ketlands restoration/enhancement;
Long-term environmental monitoring: and
Institutional controls, including restrictions on
ground",'ater use.
3 .
4.
5.
The u.s. Department of Interior (DOI) and the Massachusetts
Department of Environmental Quality Engineering (MA DEQE) have
raised concerns that, if the PCB-contaminated sediments in Middle
Marsh are not excavated, they may continue to pose a long-term
threat to a variety of aquatic and terrestrial organisms that
inhabit the Middle Marsh area. In vie~ of these concerns, EPA
has determined that additional studies including biological
studies are needed before a final remedial action decision on
Middle Marsh is given. Therefore, this Record of Decision will
not incorporate a remedial action decision on Middle Marsh.
Instead, this portion of the study area will be studied as a
separate operable unit and the decision on the appropriate
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5
v.
SITE CHARACTERISTICS
Tr.s si~nificar.t findings of the Remedial Investigation are
sU~larized below:
A.
General
Field Investigations were conducted in 1986 and 1988. The
results of the investigations revealed high concentrations of.
polychlorinated biphenyls (PCBs) in surface soil, subsurface
soils and sediments. In addition, the results indicated the
presence of volatile organic compounds (VOCs) and inorganics in
groundwater sampled from a network of wells both on- and off-
site. 1
Based on the results of the two RIs, EPA has concluded that the
sources of contamination at the Sullivan's Ledge site are on-site
soils, PCS-contaminated sediments that have washed off of the 12~
acre site into t~c unnamed stream and wetland areas, and wastes'
disposed of in the former quarry pits. EPA has further
determined that surface water and overburden and bedrock
groundwater both on- and off-site are significantly contaminated
from wastes contained within the pits.
Surface water and groundwater represent the major migration
pathway~ for volatile organic contaminants. Erosion of soils
fro~ the site into the unnamed stream is the most significant
pathway for movement of PCBs and PAHs. Airborne transport is of
little consc~uence at the site.
In general, a marked pattern of decreasing contamination (both in
terms of nu~~ers of contaminants and their respective
concentrations) is evident with increasing distance from the
site. The pattern is typified, with few exceptions, by the drop
in conce~~rations of volatile organics in both groundwater and
surface waters north of the site. Surface soil contamination
exhibits a similar pattern with respect to contaminants found in
this medium. Sediments, however, exhibit a comparatively
undiminished loading of PCBs throughout the golf course area.
This is apparently a function of the manner in which PCBs are
distributed in the environment; primarily as adsorbed materials
to soils, so that their distribution mirrors that of sediment
deposition along and from the stream.
'Except where otherwise noted, "on-site" is used throughout
this ROD to describe the 12-acre disposal area and "off-site"
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B.
6
Bydrogeoloav
Hydrogeologic investigations were conducted as part of the Phase
I ~~d rh3se !I RIs to characterize groundwater flow and
contaminant transport. Based on the geological and geophysical
evidence presented in the reports, the following conclusions are
made:
1.
The shallow bedrock is highly fractured and the
fracture planes vary both in frequency and orientation.
This means that the shallow bedrock exhibit~ the
properties of a porous medium, with groundwater flowing
in thG direction of the hydraulic gradient.
contarinant migration in the shallow bedrock
groundwater would be expected to follow the shallow
groundwater flow paths and form contaminant plumes.
The deep bedrock contains fewer fractures than the
shallow bedrock; these discrete fracture planes follow
a regional north/northwest lineament trend.
contaminant migration in these deeper fractures is
controlled by the orientation of these fractures. The \
potential exists for contamination to migrate.
relatively long distances along these specific
. fractures. However, given.the significant depths (>200
feet) and unpredictability of the fracture .
orientations, the exact locations of all deep bedrock
fractures are technically infeasible to determine.
Furthersore, the possibility of .locating all pockets of
contamination within these fractures is highly
unlikely.
2.
On a regional scale, groundwater flow in the overburden, shallow
bedrock and ceep bedrock is to the north. On a local scale,
ground',..'ater flow in the overburden and shallow bedrock is
influenced by surface features (i.e. the unnamed stream). Flow
in the deep bedrock locally is controlled by the distribution and
orientation of fractures. Local groundwater flow at the site is
from the southwest corner to the northeast corner (see
Figure 3). Flow from the southwest corner of the site enters the
quarry pits and discharges out of the pits. Part of this flow
discharges into the overburden and the unnamed stream. The
rer.,ainder of the floTW discharges into the bedr-oc.K. Cor.:ponents of
ground~ater flow in the bedrock discharges to surface water
bodies north of the qUarry pits. A more detailed discussion of
groundwater flow is presented in Chapter 4 of the Phase II RI.
... - ~-,. ,".. - -
--~.......-..-_._---..-._. - ..
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7
C.
Soil
~=::~ c: ~he ~'.:l~i'..an's Ledge site is covered by a layer of fill
~hict~ overli~s tha bedrock and quarry pits. The thickness of the
fill generally increases to the south and east across the
property ~ith the maximum observed thickness of 22.4 feet of fill
(exclusive of the quarry pit areas) found in the southwest corner
of the site. The fill is found throughout the site property,
except in the northwest corner of the site where bedrock outcrops
were observed, and the southeast corner of the site, where
. glacial till and swamp deposits were found. Field observations
indicated that fill material on the site is largely derived from
local glacial deposits (silt, sand, gravel and rock fragments),
with rubber tires, wood, scrap metal, and metal objects mixed in.
The RI reports identified areas of soil contamination. organic
conta~ination at the site was detected at all sampling depths
within the unsaturated layer. Soil samples generally contained
low total concentrations of volatile organic compounds.
Unsaturated site soils are primarily contaminated with
polychlorinated biphenyls (PCBs) and polycyclic aromatic
hydrocarbons (PAHs) and lead. Although contamination has
occurred thro~:1hout most of the site, the soils along the eastern
and southern boundaries contain the highest concentrations of
PCBs and PARs. The highest lead concentration, greater than 10
ti~es the mean value, was detected in unsaturated soils along the
southern boundary of the site. Maximum measured soil
concentrations of PCBs, PARs and lead are 2,400 ppm, 88.5 ppm and
4,600 ppm, respectively.
D.
Sedir.1ents
Soils have eroded from the site into the unnamed stream and have
been transported from the site. As a result, the sediments in
the unnamed stream, Middle Marsh, four golf course water hazards,
and a portion of the Apponagansett Swamp are contaminated with
PCBs from the Sullivan's Ledge site. contaminants detected in
sediffients include inorganics and organics, primarily PCBs and
PARs.
significant1evels of PCBs in sediments were found within the
study area, as described below:
LocatlQn
Unnamed stream
Middle Marsh
Golf course water hazards
Apponagansett Swamp (south)
Apponagansett Swamp (north)
fo!axirou1\\
PCB concentration
90
60'
18
19
18
(mq/kq)
.. .. .,- ---....- --..-----. -..-- -
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8
The sediments in the stream also contained maximum concentrations
of alu~inum and iron of 40,000 mg/kg and 374,000 mg/kg,
re 5p<::Ct i.vsly. :;l.:.mar:::t.:s PAHs were a 1so frequently detactec. in the
unnamed stream, with average concentrations less than 1 mg/kg for
each co~pound. .
E.
Quarrv Pits
Based on historical documentation and data from the field
investigations, four quarry pits estimated to be as deep as 150
feet have been identified. The quarries are located in fractured
bedrock. Based on historical documents, the contents of the pits
may include rubber tires, scrap metal, automobiles, transformers,
capacitors and miscellaneous rubble. Technical difficulties with
drilling in quarries which have been filled with debris and solid
~aste prevented direct sa~p1ing of the contents of the quarries.
Ho.."eve:-, groundwater sampling was conducted immediately adjacent
to the ~arry pits in order to characterize the liquid contents
of the pits.
F.
Groundwater
Volatile organic compounds (VOCs) were the predominant
groundwater contaminants identified in the Phase I and Phase II
RIs. VOCs were identified in overburden groundwater, shallow
bedrock groundwater (i.e. less than 100 feet), and deep bedrock
groundwater:
1.
Overburden groundwater
Volatile organic contaminants detected in groundwater- samples
from overburden monitoring wells include: benzene, 1,2-
dichloroethene, trichloroethene, ethylbenzene, chlorobenzene and
vinyl chloride. Total VOCs measured during the RIs ranged from
not detected to 8.2 ppm. VOCs in overburden groundwater were
greatest in the vicinity of the northernmost quarry pit.
The overburden groundwater contaminant plume is oriented in the
same northeastern to northern direction as the projected
groundwater flow direction. Figure 4 is a VOC contaminant plume
map for the overburden aquifer. As illustrated in the figure,
the overburden contaminant plume extends from the site, with the
highest contamination around the northernmost pit, to the
southern edge of Middle Marsh.
.._-.. -- -- -.--. -----.
. - --..... -.----
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9
'- .
Shallow bedrock groundwater
,.,\..,.. ~'::;.ll,:'.,' =-<: ~~':cy. plur.\e is similar in configuration a'nd
10~dtion to t~~ ov€rb~rden plume. Ho~ever, VOC contamination in
ground~ater increases with depth. The VOCs detected in shallow
bedrock qroundwater were similar to the VOCs detected in the
o\'€rbu!'d~n aqiJi fer, but ....'ere detected at increased frequency and
concentration. The following specific VOCs were detected:
COITtP,=,und
Ranqe of Detected Concentrations
(Uq/ 1 )
5 - 1200
13 - 51,000
5 - 4000
36 - 6900
Benzene
1,2-Dichloroethene
Trichloroethene
Vinyl chloride
To~al \FOCs detected in o~-site and off-site monitoring wells
during the Phase II RI ranged from not detected, in MW-11, an
upgradient well, to 54,000 ug/l in GCA-1 located at the northeast
corner of the site.
3 .
Deep bedrock groundwater
The deep bedrock groundwater system extends from 100 to 300 feet
beloN ground surface. Information gained by the geophysical
survey cor.~ined with information obtained during the actual-
borehole drilling indicated that at these depths, bedrock is more
uniforr.\ ,,'ith :e1,o.'er fractures. contaminant transport at these
depths would occur p~imarily along specific fractures.
During the Phase II RI, four W~stbay multilevel sampler wells
(ECJ-1,2,3,4) were installed to investigate the deep bedrock
system with respect to groundwater flow direction and extent of
conta~i"'~tion. with the exception of ECJ-2, each Westbay well
was sampled at six different zones.
Average total VOCs in each of the four Westbay wells were
detected as follows:
Total VOCs (ppm)
Zone ECJ-1 ECJ-2 ECJ-3(upgradient) ECJ-4
1 9.4 21.7 not detected not detected
2 50.2 30.6 0.02 not detected
3 94.6 38.8 0.01 0.01
4 90.1 23.3 0.01 0.01
5 56.0 27.3 0.01 153
6 ' 9.3 0.02 0.01
. - --.....--------
---------- -- -- --- ---
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10
It is of particular significance that during one round of
sa~pling of zone 5 of ECJ-4, trichloroethene was detected at an
Q~C~~tc~ c=~ce~tration of 270 ppm, at greater than 200 feet below
the ground su~face and over 1,000 feet from the site. At this
concentration, trichloroethene was detected at approximately 25
percent of its solubility, suggesting that dense non-aqueous
phase liq".Jids (DNAPLs) may exist in the quarry pits or in on- or
off-site d~ep bedrock fractures.
Contaminants in the deep bedrock were consistent with those found
in the overburden and shallow bedrock. Trichloroethene,
1,2 - dichloroethene and vinyl chloride account for 90 percent of
the contamination found in the deep bedrock. In general the
largest number and concentrations of contaminants were found near
. the quarry pits. With depth the distribution of contaminants
were controlled by their physical properties (i.e. density) and
the presence and orientation of fractures. Chapter Five of the
Phase II Rl rresents a more detailed discussion of the
distribution of contamination.
G.
Surface Water
Surface waters throughout the study area are affected by
conta~inants associated with the site. Contaminants from the'
site enter the unnamed stream as dissolved constituents from
overland runoff and from groundwater seeps. The following
observations support this suggestion:
1.
Seeps to the unnamed stream were observed at the south end
of the site, along the stream's length and at the northeast
end of the site.
2.
Surface water was contaminated at the south end of the site
with volatile organic compounds.
3 .
At a seep discharge at the north end of the site,
water was also contaminated with many of the same
and concentrations as surface waters at the south
site.
surface
chemicals
end of the
4.
Surface water contaminants detected at the south and north
ends of the site were similar to those in groundwater in
their respective vicinities.
Table 8-1 of the Phase I RI lists the major surface water organic
and inorganic contaminants and their concentrations ranges and
provides an indication of their prevalence in surface waters,
based on Phase I sampling. As indicated by the table, benzene,
chlorobenzene, trichloroethene, trans-1,2-dichloroethene, vinyl
chloride, aluminum, barium, copper, iron and lead are the primary
surface water contaminants.
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11
~hi~tecr. s~r~ace water stations were sampled during the Fhase II
field investigation. In general, VOCs were detected during this
fi~ld inv~5tigation at decreased frequency and concentration in
co~parison to Ph~s~ I results. VOCs detected in groundwater
seeps include trichloroethene, chlorobenzene, benzene, xylenes
and 1,2-dichloroethene at maximum concentrations of 9, 43, 45, 68
and 675 ppb, respectively. Of the five surface water stations
sampled for semi-volatile organic compounds (SVOCs), two stations
contained measurable SVOCs. station SW-8 (seep location)
contai~ed low levels of naphthalene (16 ppb) and n-
nitrosodiphenylamine (16 ppb). As in the case of organic
contaminants, inorganic contaminant concentrations are
significantly higher at seep locations. Seeps SW-6, SW-8 and SW-
9 show elevated concentrations of iron. Aluminum contamination
was also noted at seeps SW-6 and SW-9. In addition, the Phase II
data indicated detectable in-stream concentrations of lead,
silver, zinc and barium. Figures 5-8, 5-9 and 5-16 of the Phase
II RI depict the surface water and seep sampling results for both
inorganics and organics.
H.
Biota Investigation
In October 1987, a biological investigation was conducted for the
unnamed stream, Middle Marsh, and Apponagansett Swamp, habitats
potentially impacted by wastes emanating from the Sullivan's
Ledge site. The investigation included aquatic biota sampling at
predetermined stations (see Figure 5-17 RI); collection of water
quality para~eters; and characterization of aquatic and
terrestrial habitats. The objective of the investigation was to
qualitatively assess general conditions of aquatic ecosystems
(stream, marsh, and swamp), such as obvious stress (i.e., absence
of certain organisms), presence of indicator species, and
indications of pathological stress.
1.
Aquatic Habitats
Aquatic habitats located on or associated with the Sullivan's
Ledge site include: the unnamed stream (Stations B1 through B7);
forested wetlands known as Middle Marsh in the interior of the
golf course (stations B8 through B10); a series of shallow ponds
(water hazards) between Middle Marsh and the Conrail line
(Station B11); and the Apponagansett Swamp, a forested wetlands
north of the golf course (stations B12 through B16). Aquatic
invertebrates collected and species identified at sampling
locations in these areas are listed in Table 5-2 (RI).
.... ---- .--- _aa..._.------------'. ....
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12
Three reference stations were established upstream from the
groundwater seeps (B1, B2, and B3). At those stations, typically
four to fiv~ a~1atic species were identified per site with 23 to
26 ~rg~~i~~s collected. Groundwater seeps are located
immediately downstream of Station B3 and immediately upstream of
station B5. Fewer organisms were collected and fewer species
were identified at these sites compared to the reference
stations. Only two to 12 total organisms were collected, and one
to four different species were identified at each station. Thus,
Stations B4 through B8 were impacted by the seeps. stations B12,
B14, B15 (Apponagansett Swamp) yielded the highest number of
organisms collected and species identified. The organisms
(collected from stations B12 to B15) were representative of those
typically found in a wetland system. The highest number of
organisms found in the Apponagansett Swamp may be attributable to
the type of forested wetland which typically supports a more
diverse and dense assemblage of aquatic organisms.
2.
Terrestrial Habitats
Three types of habitats for terrestrial organisms were
identified. These habitats are referred to as old field,
forested palustrine wetland, and mowed grassland (see Figure 5-17
RI). Old field communities are those areas that were once
cleared ~d now are in the process of reverting to woodland. .
Most of the habitats found on-site have. been identified as old
field communities. Palustrine forested wetlands are the types
found off-site in the middle of the golf course and north of the
Conrail rail line. Palustrine wetlands are non-tidal wetlands
dominated by emergent mosses, lichens, persistent emergents,
shrubs, or trees. Mowed grassland areas are the cultivated
fairways of the ~haling City Country Club.
A complete discussion of site characteristics can be found in
Chapters 4 through 7 of the Phase I RI and Chapters 4 and 5 of
the Phase II RI.
VI.
Summary of site Risks
A Risk Assessment (RA) of the site was
probability and magnitude or potential
environmental effects from exposure to
site.
performed to estimate the
adverse human health and
contaminants found at the
Fifty-nine contaminants of concern, listed in Table 1, were
selected for evaluation in the RA. These contaminants constitute
a representative subset of the more than 80 contaminants
identified on-site in the RI. The 59 contaminants were selected
based on their relative toxicity, concentration, and mobility and
persistence in the environment.
-...--
-..---.-.-
--.---...--.-...--.
--.- --- - ----- ---
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13
potential human health risks associated with exposure to the
conta~inants of concern in surface soils, sediments, air, surface
water and ground~ater were estimated quantitatively through the
d=~'clop~znt cf ~€~cral hypothetical exposure scen3ric~.
1~=re~~~t~l lifetime carcinogenic risks were estimated and the
potential for noncarcinogenic adverse health effects were
evaluated for the various exposure scenarios. For carcinogenic
compounds, risks are estimated by multiplying the estimated
exposure dose by the cancer potency factor of each contaminant.
The p=oduct of these two values is an estimate of the incremental
cance~ risk. For noncarcinogenic compounds, a Hazard Index (HI)
value was estimated. This value is a ratio between the estimated
exposure dose and the reference dose (Rfd) which represents the
arnount of toxicant that is unlikely to cause adverse health
effects. Generally, if the HI is less than one, the predicted
exposure dose is not expected to cause harmful human health
effects. If the HI exceeds one, the potential to cause
noncarcinogenic hUwan health effects increases.
Exposure scenarios were developed to reflect the potential for
exposure to hazardous substances based on the characteristic uses-
and 10cat~on of ~h~ site. A factor of special note that is
reflected in the Risk Assessment is that portions of the study
area are part of a golf course. ~dditionally, the Risk
Assessment took into account the facts that access to the site is
restricted and the land is zoned for commercial development. The
Risk Assessment also considered the proposed future use of the
site as a soccer field..
Direct contact with surface soil was judged as the most likely
exposure route to result in potential health hazards under
present site conditions. Although on-site groundwater is not
currently used for drinking water, the risks associated with its
consu~ption were evaluated because it is classified as a
potential source for drinking water. Inhalation of on-site
airborne contaminants was also evaluated quantitatively. other
potential public health and environmental risks associated with
direct contact with contamin~ted surface water and sediments on-
site and off-site were also discussed in the RA.
A.
Direct Contact with Surface Soil
Human health risks were calculated for an adult assuming
occasional site visits and inadvertent contact with contaminated
soil. Similar calculations were made for an older child (i.e., 8
to 18 years old) who may play or loiter occasionally on the site.
The risks were assessed assuming both mean contaminant
concentrations and maximum concentrations. A range of probable
absorption rates for different chemicals (i.e., VOCs, SVOCs,
PCBs, and inorganics) was used to estimate body dose. Calculated'
incremental carcinogenic risks were determined to be greater for
risks associated with exposure to contaminated soil for a child
- - . -. .'-
. .. -. ..----------- ___..._0._._._- .
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14
than for a~ adult. The incremental lifetime carcinogenic risks
for an older child coming in contact with surface soil or.-site
ranged from 5xlO.6 usin~ site-wide average contaminant
cc~centrations to 5xlO. using site-~ide ~axirnum ccr.ta~inant
~orlce.I~:i'i:ttio~~. PCEs and total PA..Tis contributed the majority of
the total risk.
The Risk Assessment further specified carcinogenic risks to an
older child and an adult from exposure to off-site surface soils.
For an older child coming in contact with surface soil off-site,
incremental lifetime carcinogenic risks ranged from 8X10.9 to
lX10.8. In co~paIison, for an adult coming in contact with
surfac~ soil off-site, incremental lifetime carcinogenic risks
ranged from 3X10.7 to 5X10.7, reflecting the greater frequency of
exposure assumed for the adult. PCBs contributed the major
portion of the total risk using both average contaminant
concentrations and maximum contaminant concentrations.
Noncarcinogenic risk estimates were also specified in the Risk
Assessment. Hazard indices (HIs) calculated for exposure to
contaminat~d s~il are all less than one with the exception of
incidental ingestion of on-site soils by children. A HI greater-\
than one is attributed tc only one chemical. This HI of 3.7 is
attributed to the maximum concentration of lead detected in an
on-site shallow soil sample.
B.
-Ingestion of Groundwater
Estimated lifetime carcinogenic and noncarcinogenic risks for
exposure to groundwater were greatest for ingestion scenarios.
Groundwater on-site is not currently used for drinking water, but
does re9res~nt a pot~ntial future source. According to criteria
established by EPA Groundwater Protection Strategy guidelines,
the aquifer underlying the site is classified as Class IIB
aquifer, (i.e., a potential source for future use). Under the
Massachusetts DEQE classification system, the aquifer is
considered Class I, based on the same potential use. Therefore,
the incremental lifetime carcinogenic risk and the
noncarcinogenic health risks associated with the ingestion of
contaminated groundwater were assessed.
The total incremental carcinogenic risk if a person were to drink
the groundwater found under the site for a lifetime containing
contaminants of concern at the mean and maximum concentrations,
based on the Phase II sampling, was estimated at 1.7xlO-2 and
5.4X10.', respectively. Benzene, trichloroethene, vinyl
chloride and PCBs contributed over 99 percent of the total cancer
risk.
For these same conditions, the total estimated exposure dose
exceeds a HI of one. Therefore, there is also an increased
potential to cause adverse noncarcinogenic human health effects.
-.. ...- '''.'-.-. .". .....--.-----...-..----..-.---
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15
T~~ haz~rd inci=es associated with ingestion for a lifetime of
groundwater containing contaminants of concern at the mean and
~axiroum concentrations, based on Phase II sampling, were
~~+~~~~~~ ~t F1 ~"d 304, respectively. In both cases, 1,2-
dichloroethene is the only contaminant with an estimated exposure
dose greater than the respective reference dose.
C.
Exposure to Sediments
The public health risk assessment performed for the Phase I and
Phase II RIs examined risk associated with exposure to
conta~inated sediments in the unnamed stream and water hazards
including direct contact with or incidental ingestion of
sedi~ents for a child and' for an adult golfer. The highest
incremental carcinogenic risk was 1.7X10.S, based on direct
contact by an older child with the maximum concentrations of
ccnta~inants in the unna~ed stream.
The risk assessroent also evaluated potential impacts to
environmental receptors exposed to contaminated sediments. For
the swall maIT~als, rodents and aquatic organisms that inhabit the
area, the potential exists for exposure to site associated
contaminants through the skin, by ingestion or through' the food
chain. Of greatest concern is exposure to PCBs because they are
difficult to eliminate from the body and may affect the animals
and other organisms.
Two approaches were used to evaluate the environmental risk .posed
by the contaminated sediments.
The first approach was to determine levels of PCBs and total
organic carbon (TOC) at various sampling locations, and then to
co~pare those values to the Interim Sediment Quality criteria
(SQC), which vary depending on the TOC value. The sediment
quality criteria are numbers which predict the relationship
bet~een contaminant levels in sediments and the Ambient Water
Quality Criteria (AWQC) which protects wildlife that consume
aquatic organisms.z There are three levels of SQCs. The upper
level represents a 97.5% probability that .PCB levels in
interstitial water (the water between sediment particles) will
exceed AWQCs. The mean level represents a 50% probability of the
same event, and the lower level represents a 2.5% probability.
Generally, the greater the probability of PCB levels exceeding
AWQCs, the qreater the risk to wildlife that consume aquatic
2For PCBs, the ambient water quality criterion for the
protection of aquatic life to allow safe consumption of aquatic
organisms by wildlife is 0.014 ug/l.
-_._-_..-.._~..-. .
. - ,-'-'-"
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16
organisms.'
At Sullivan's Ledge, PCBs in sediments exceeded the mean SQC
v~l~)~ ~f ~0 ugPC8s/gTOC in all portions of the unn3med stream and
in most portions of the water hazards. Furthermore, sediment PCB
levels were greater than the upper SQC value in most portions of
the unnamed stream and its tributary, and in some portions of the
water hazards. In one location, the maximum level was 500 times
greater than the upper SQC value.
Based on the comparisons between the SQCs for PCBs and measured
PCB levels in sediments, EPA has determined that a potential
exists for significant risk to wildlife through consumption of
aquatic organisms exposed to PCB-contaminated sediments within
the unnamed stream, its tributaries and portions of water hazards
1 and 2.
The second approach was used to assess risks to the aquatic
organisms in contact with the PCB-contaminated sediments.
PCB tissue concentrations of these aquatic organisms are
projected to be equal to or, in some cases, in excess of those
concentrations in the sediment. Assuming a sediment:tissue
Bioconcentration Factor (BCF) of 1, the range. of PCB tissue
concentrations in aquatic organisms are estimated at less than
1.0 to 118 ppm in the unnamed stream and less than 1.0 to 18.0
ppm.in the water hazards. PCB tissue concentrations higher than
0.4 ppm in freshwater fish have been associated with reproductive
impairment. Therefore, based on assumed tissue levels in aquatic
organisms in the unnamed stream and water hazards ('1 and 2),
aquatic organisms in these areas may be at risk of reproductive
irnpairment or other adverse effects.
The results of the biota investigation, as described in Section
V.H, further indicate that the contaminants from the site impact
the aquatic biota in the unnamed stream. Reduced numbers and
species of organisms were observed from below the seep areas to
the Middle Marsh area.
The
Due, in part, to the presence of orange floc attributable to iron
precipitates, both the water and sediments within the unnamed
stream and water hazards are aesthetically unappealing, in
violation of Massachusetts water quality standards.
D.
Exposure to Surface Water/Seeps
. 3The derivation of upper, mean and lower value SQCs are
further discussed in Appendix E of the Feasibility study.
4
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17
The public health risk assessment, based on the Phase I sampling
results, evaluated the potential risks associated with direct
ccnt3ct exp~sure to surface water. Various surface water
exp~:ure ~~~na~ios were developed to evaluate the potential
carcinogenic risks and noncarcinogenic health effects. Based on
these scenarios, exposure to surface water is not expected to
cause non-carcinogenic human health effects. The lifetime
incremental carcinogenic risks ranged from 5x10.13 to 4X10.7. The
maximum incremental carcinogenic risk (4X10.7) was derived from a
child's direct contact exposure to groundwater seeps. Exposure
to n-nitrosodiphenylamine accounted for the majority of this
risk.
Concentrations of chemicals of concern detected in surface water
were compared to their respective ambient water quality criteria
(AWQC) to evaluate potential risk to aquatic organisms. The
following results were noted:
1.
2.
The mean or maximum detected concentrations in surface water
of 10 chemicals exceeded their respective freshwater chronic
A~QC during the Phase I field investiga~ion (see Table 6-18\
RI). Mean concentrations of bis(2-ethylhexyl) phthalate
(BEHP) at 8.13 ug/1: mercury at 1.56 ug/1: copper at 10.44
ug/1: silver at 8.9 ug/l; and lead at 26.8 ug/l exceeded
chronic criteria of 3.0, 0.012, 6.S, 0.12, and 1.3 ug/l,
respectively.
~aximum concentrations of two chemicals exceeded chronic
criteria while their mean concentrations did not. The
maximum detected concentration of nickel of 82.0 ug/1
exceeded the criteria of 56.0 ug/1, and the maximum
concentration of chlorobenzene of 53 ug/1 was in excess of
the 50 ug/1 criteria level.
3.
PCBs and pentachlorophenol were detected in surface waters
only once during Phase I sampling. A PCB concentration of
1.7 ug/1 (see Table 6~18 RI) at SW-207 exceeded the final
residue value criterion of 0.014 ug/1 for PCBs in
freshwater. The 8 ug/1 pentachlorophenol concentration (see
Table 6-18 RI) found at SW-301 exceeded the chronic criteria
of 3.2 ug/1.
4.
During Phase II field investigations, mean concentrations of
BEHP, cyanide, lead, and silver at 251, 48.2, 11.0 and 6.38
ug/1, respectively, exceed their respective chronic water
quality criteria (see Table 6-18 RI). Maximum detected
concentrations of zinc also exceeded its respective
criteria.
Based on comparisons between contaminant concentrations detected
. -.... . - .'-' .
0_"_"'. . -..----- .
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18
in surface water and their respective water quality criteria, as
describ~d above, a potential risk exists for aquatic organisms
due to exposure to contaminants in surface water of the unnamed
strea~.
Risk to aquatic organisms due to PCB exposure in water cannot be
accurately evaluated by comparing detected concentrations of PCBs
to thE respective water quality criteria. The detection limit
for PCBs was 1.0 ug/1 (during both investigations), and the
criteria concentration is 0.014 ug/1. However, PCB exposure via
water for aquatic organisms is likely in the unnamed stream and
water hazards because of high levels of PCBs detected in area
sediments. Adverse effects to aquatic organisms can occur as a
result of exposure to the 1.7 ug/1 concentration detected at SD-
614 during Phase I. It is of particular concern that PCB
concentrations (Aroclor-1254) of 1.2 and 1.5 ug/1 are associated
with measurable effects to growth, reproduction, survival, and/or
metabolic upset in some aquatic organisms.
A cor:.plete discussion of site risks can be found in Chapter 8 of
the Phase I RI and Chapter 6 of the Phase II RI.
VII.
DOCUXENT~TION OF SIGNIFICANT CHANGES
EPA adopted a proposed plan (p!eferred alternative) for
re~ediation of the site in January 1989. Components of the'
preferred alternative included:
1-
2.
3.
4.
5.
6.
7.
B.
9.
site preparation;
Excavation, solidification and on-site disposal of
contaminated soils:
Excavatio~, dewatering, solidification and on-site disposal
of contaminated sediments from the unnamed stream and golf
course water hazards:
Construction of an impermeable cap;
Diversion and lining of a portion of the unnamed stream;
Collection and treatment of groundwater from on-site
overburden and shallow bedrock:
Wetlands restoration/enhancement;
Long-term environmental monitoring; and
Institutional controls, including restrictions on
groundwater use.
EPA has ~ade t~o significant changes to the proposed plan.
First, the proposed plan outlined the evaluation of wetland
remediation options for Middle Marsh. Three remedial action
options were described ranging from no action to excavation and
treatment of sediments from 9.5 acres of Middle Marsh. Based, in
part, on the significant adverse short-term environmental impacts
associated with the excavation and disruption of the forested
wetlands, the preferred alternative, as described in the proposed
plan, included the no action option for Middle Marsh. However,
.,- . -.. -.-..
.. -.- ...--
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19
since issuing the proposed plan, EPA has re-evaluated options
relating to Middle Marsh and has determined that additional
studies are needed. In addition, the U.S. Department of Interior
'~0!) an1.th~ ~~s~achusetts Department of Environ~er.tal Q~~lity
Engineering (MA DEQE) have raised concerns that, if a porticn of
the PCB-contaminated sediments are not excavated, they may
continue to pose a long-term threat to a variety of aquatic and
terrestrial organisms that inhabit the Middle Marsh area. In
view of these concerns, EPA has determined that additional
studies, including biological testing, are needed before a final
re~edial action decision on Middle Marsh is given. Therefore,
this Record of Decision will not incorporate a remedial action
decision on Middle Marsh. Instead, this portion of the study
area ~ill be studied as an operable unit and the decision on the
appropriate remedial action for Middle Marsh will be made in a
separate ROD.
Because the decision on remedial action in Middle Marsh has not
been included in this ROD but will be addressed in a subsequent
ROD, EPA has re-evaluated the eight site alternatives to
dete1~.ine to what extent factors relating to Middle Marsh were
used to scree;) sit"e Cil ternatives. EPA has determined that
components of the site alternatives associated with Middle Marsh
were not the determining factors in screening out site
alternatives and in choosing SA-5 as the selected remedy.
Therefore, the site alternatives, as described in the proposed
plan will not be changed by deleting components relating to
Middle Marsh (i.e. cost). However, analysis of site
alternatives, as discussed in this ROD, will not focus on
components or issues resulting from proposed remedial action in
Middle Marsh.
Second, EPA has determined that locations other than the site's
disposal ~~ea may require remediation due to soil contamination.
Therefore, a sampling program will be implemented to determine
the extent of soil contamination in the unsaturated layer in off-
site areas irnnediately north of Hathaway Road and east of the
existing fence along the eastern boundary of the site. EPA has
estimated that the additional volume of soils that will be
excavated from these areas will be minor in comparison to the
total 24,000 cubic yards estimated in the Feasibility Study.
Therefore, costs associated with the excavation, disposal and/or
treatment of soils from outside the site's disposal area are
projected to be minimal in comparison to the total estimated cost
of the ret'".e:!y. In the unlikely event that projected costs are
substantially greater than expected, the public will be notified
and the ROD will be amended. .
VIII.
DEVELOPMENT AND SCREENING OF ALTERNATIVES
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20
A.
statutory Requirements/Response Objectives
Prier to tt.-s f-a::>sage of the Superfund A!!icndments and
Reauthorization Act of 1986 (SARA), actions taken in response to
releases of hazardous substances were conducted in accordance
with CERC~. as enacted in 1980 and the revised National Oil and
Hazardous S~bstances Pollution Contingency Plan (NCP), 40 CFR
Part 300, dated November 20, 1985. Until the NCP is revised to
reflect SARA, the pro~edures and standards for responding to
releases of hazardous substances, pollutants and contaminants
shall be in accordance with Section 121 of CERCLA and to the
maximum extent practicabl~, the current NCP.
Under its legal authorities, EPA's primary responsibility at
Superfund sites is to undertake remedial actions that are
protective of human health and the environment. In addition,
Section 121 of CERCLA establishes several other statutory
requirements and preferences, including: a requirement that EPA's
remedial action, when complete, must comply with applicable or
relevant and appropriate environmental standards established
under federal and state environmental laws unless a statutory
waiver is granted: a requirement that EPA select a remedial
action that is cost-effective and that utilizes permanent
solutions and alternative treatment technologies or resource
recovery technologies to the maximum extent practicable: and a
statutory prefe.rence for remedies that permanently and sig-
nificantly reduce the volume, toxicity or mobility of hazardous
wastes over remedies that do not achieve such results through
treatment. Response alternatives were developed to be consistent
. with these Congressional mandates.
A nu~ber of potential exposure pathways were analyzed for risk
and threats to public health and the environment in the SL Risk
Assessment. Guidelines in the Superfund Public Health Evaluation
Manual (EPA, 1986) regarding development of design goals and risk
analyses for remedial alternatives were used to assist EPA in the
development of response actions. As a result of these
assessments, remedial response objectives were developed to
mitigate existing and future threats to public health and the
environment. These response objectives are:
1.
Prevent or mitigate the continued release of
hazardous substances to the unnamed stream, Middle
Marsh, and Apponagansett Swamp;
. Reduce risks to human health associated with direct
contact with and incidental ingestion of contaminants
in the surface and subsurface soils;
Reduce risks to animal and aquatic life associated with
the contaminated surface soils and sediments:
2.
3.
4.
-------
5.
~
v.
7.
21
8.
hazardous contaminants;
Maintain air quality at protective levels for on-site
~ory.ers and nearby residents during site remediation:
R~du~e further migration of groundwater contamination
from the quarry pits in the upper 150 feet of the
bedrock groundwater flow system:
Significantly reduce the mass of contaminants in
groundwater located in and i~~ediately adjacent to the
q-:~arry pits;
Provide flushing of groundwater through the pits to
encourage continued removal of contaminants at the
site; and
l1ir.irnize the threat posed to the environment from
contaminant migration in the groundwater and surface
water.
9.
B.
7cchnology and Alternative Development and screeninq
CERCLA, the NCP, and EPh guidance documents including, "Guidance.
on Feasibility Studies Under CERCLA" dated Karch 1988, and the
"Interim Guidance on Superfund Selection of ~emedy" (EPA Office
of Solid ~aste and Emergency Response (OSWER»), Directive No.
9355.0-19 (December 24, 1986) set forth the process by which
remedial actions are evaluated and selected. In accordance with.
the'se require:J7.el1ts and gu idance documents, a range of
alternatives were developed for the site involving treatment that
would reduce the mobility, toxicity, or volume of the hazardous
substances as their principal element. In addition to the range
of treatment alternatives, a containment option involving little
or no treatment and a no-action alternative were developed in
accordance Witil section 121 of CERCLA.
section 121(b) (1) of CERCLA presents several factors that at a
mini~u~ EFA is required to consider in its assessment of
alternatives. In addition to these factors and the other
sta~utory directives of Section 121, the evaluation and selection
process was guided by the EPA document "Additional Interim
Guidance for FY '87 Records of Decision" dated July 24, 1987.
This document provides direction on the consideration of SARA
cleanup standards and sets forth nine factors that EPA should
consider in its evaluation and selection of remedial actions.
The nine factors are:
1.
2.
3.
4.
Corpliance ~ith Applicabl~ or Relevant and Appropriate
Requirements (ARARS).
Long-term Effectiveness and Permanence.
Reduction of Toxicity, Mobility or Volume.
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22
5.
ImplementaDility.
Community Acceptance.
6.
7.
state Acceptance.
8.
Cost.
9.
Overall Protection of Human Health and the Environment.
Chapter 8 of the Feasibility study identified, assessed and
screenej technologies based on engineering feasibility,
implementability, effectiveness, and the nature and extent of
~astes produced by such technologies. These technologies were
combined into source control (SC) and management of migration
(MM) alternatives. Chapter 9 in the Feasibility study presented
the r~:-~ ~ j c'! c:~. terna t i ves developed by combining the technologies
identified in the previous screening process in the categories
required by OSWER Directive No. 9355.0-19. Each alternative ~as
-then evaluated and screened in Chapter 9 of the Feasibility
study. The purpose of the initial screening was to narrow the i
number of potential remedial actions for further detailed
analysis while preserving a range of options. Of the t~enty-one
source control and six management of migration remedial.
alternatives screened in Chapter 9, seven source control and
three management of migration alternatives were retained for
detailed analysis. Table 2 identifies the source control and
management of migration alternatives that were retained through
the screening process, as well as those that were eliminated from
further consideration.
IX.
DESCRIPTION/SU~~RY OF THE DETAILED AND COMPARATIVE
ANALYSIS OF ALTERNATIVES
This section presents a narrative summary and brief evaluation of
each alternative according to the evaluation criteria described
above. A tabular assessment of each site alternative can be
found in Table 12-18 of the Feasibility study.
A.
Source control (BC) Alternatives Analyzed
Source control alternatives were developed to address hazardous
substances remaining at or near the area at which they were
originally located and not adequately contained to prevent
migration into the environment. At the SL site, SC alternatives
were developed to address contaminated material inside the quarry
pits, on-site contaminated soils and subsoils and PCB-
contaminated sediments.
The source control alternatives evaluated in detail for the site
.,.-. - ..... ......------.----:--....
---
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23
include a minimal no action alternative (SC-l); a containment
~lternative fer soi1s (SC-2): three treatment alternatives for
soils: in-situ vitrification (SC-3), solidification (SC-4), on-
5it~ ~"~in~T~tion (RC-S): and two excavation/treatment
~l~~pn?~ivp~ for sediments: on-site incineration (SC-G), and
solidiflcation (SC-7). A detai~ed evaluation of the source
control alternatives is presented in Chapter 10 of the
Feasibility study.
B.
y.anage~ent of Migration (KM) Alternatives Analyzed
Management of migration alternatives address contaminants that
have migrated into the groundwater from the original source of
contamination. At the Sullivan's Ledge site, contaminants have
migrated into the groundwater from the quarry pits in the
direction of groundwater flow and within bedrock fractures. In
general, the direction of off-site ground~ater flow is north,
to~ard the golf course. Contaminants have also migrated into
surface water primarily from groundwater seeps and overland
ru~off. Chapter 11 of the Feasibility Study presents the
detailed evaluation of management of migration alternatives
including a minimal no action (MM-l): passive groundwater
collection/treatment systems (MM-3); and an active groundwater
collection/treatment system (MM-5).
. c.
site Alternatives (SA) Analyzed
Table 12-1 of the Feasibility study presents the combinations of
SC alternatives with MM alternatives used in the dev~lopment of
site alternatives. Eight site alternatives were developed which
range from no-action to treatment as a principal element for the
soils, sediments, and groundwater. In developing the site
alternatives, each SC alternative was subdivided into specific
areas or contamination levels. For example, the site soils were
divided into those that exceed the 10.4 present risk level, those
that exceed the 10.5 present risk level, and those that exceed
the 10.6 present risk level. This breakdown generates a range of
soil volumes and areas that could be treated. Similarly, the
PCB-contaminated sediment areas were divided into four areas:
the unnamed stream, Middle Marsh, water hazards, and the
Apponagansett Swamp. Site alternatives were developed by
combining alternatives that would logically be used together
(e.g., incineration of the soils with incineration of the
sediments). In this way, a total of eight logical, feasible site
alternatives were developed that address the contamination at the
Sullivan's Ledge site with varying degrees of treatment and
associated effectiveness, implementability, and costs. The eight
site alternatives are as follows:
. SA-l
Minimal No-Action
- --- ..-.-...-
.. ._.~_....-.__._-_._------- ..-.. --.--........
... .. ---.-... .-. -..." . ..
-------
.
. SA-2
. SA-3
. SA-4
. S.;-5
. SA-6
. 61-..-7
. SA-8
24
Containment/Passive Groundwater Collection with
Bedrock Trench and Treatment
Containment/Active Groundwater Collection and
Tr~~tment
Solidification of 10." Present Risk Soils" 10.5
Present Risk Surface Soils, Unnamed Stream
Sediments, Water Hazard
Sediments/Containment/passive Groundwater
Collection with Bedrock Trench and Treatment
~olidification of 10.5 Present Risk Soils, Unnamed
Stream Sediments, ~ater Hazard
Sedi~~nts/Containment/Active Groundwater
Collection and Treatment/Passive Groundwater
Collection with the Overburden Trench and
Treatment
In-situ vitrification (ISV) of all Soils to 10.6
Present Risk Level/Solidification of all PCB-
ccnta~inated Sediments/Passive Groundwater
Collection Utilizing the Bedrock Trench and
'lreat!:'ient
Solidification of all Soils to 10-6 Present Risk
Level/Solidification of all PCB-contaminated
Sediments in the Unnamed Stream, Middle Marsh, and
Water Hazards/Containment/Active Groundwater
Collection and Treatment
On-site Incineration of all Soils to 10.6 Present
Risk Level/On-site Incineration of all PCB-
contaminated Sediments/Containment/Active
Groundwater Collection and Treatment
A description of each site alternative is given below:
1. SA-l
Mini~al No Action
This alternative would consist primarily of restricting access to
this site. The major items associated with this alternative are
as follows:
perform security visits
perform semi-annual site visits
conduct sediment, soil, and surface water sampling to
monitor contaminant concentrations and migration
conduct a groundwater monitoring program quarterly for the
first two years and annually thereafter
conduct educational programs, including public meetings and
presentations, to increase public awareness
perform site review every five years
establish institutional controls (i.e. deed restrictions)
limiting groundwater and land use
This alternative would not be protective because it does not
.
.
.
.
.
.
.
-------
25
address Dublic health and environmental risks due to exposure to
soils, sediments and ground~ater. The alternative is not
permanent, is ineffective in the short- and long-term and does
not att::dn C'1!'01H,ct.,..'ater and surface water ARARs. .As with all
alternatives evaluated, including the selected remedy, this
alternative does not result in the attainment of maximum
contaminant levels (MCLs). Additionally, this alternative does
not use treatment as a principal element, and consequently, there
would be no reduction in mobility, toxicity or volume of the
~astes present on site. Long term monitoring and site use
restrictions would be necessary. This alternative is not
acceptable to the state. Finally, none of the comments received
from the community support a no-action alternative.
ADProxi~ate Present Worth Cost:
$1,200,000
2. SA-2
containment/passive Collection
Installation of Cap; Diversion and Lining of a Portion of the
UnnaDed Strea~; Passive Groundwater Collection; Groundwater
Treatment; and Environmental Monitoring.
-\
Alternative SA-2 is primarily a containment alternative. Under
this alternative an impermeable cap would be constructed over 11
acres of the site. A portion of the unnamed stream parallel to
the eastern border of the site would be temporarily diverted in
order to construct a concrete channel for that segment of the
stream. In addition, a passive groundwater collection system
would be installed, to intercept contaminated groundwater in the
overburden, shallow bedrock and groundwater seeps. The collected
groundwater would be treated using a combination of chemical
oxidation/filtration for metals removal and uv/ozonation for
organics removal.
v,
This alternative would achieve a short term reduction in
environmental and public health risks by reducing the direct
contact hazards associated with contaminated on-site soils and
groundwater seeps and by reducing the potential for PCB-
contaminated soils to migrate off-site via the unnamed stream.
The passive groundwater collection and treatment system would
reduce the toxicity, mobility and volume of groundwater
contaminants in collected groundwater. This containment
alternative uses readily available materials and is easy to
implement.
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26
~obility of c~nta~inants in soil. However, the long term
reliability of a cap is questionable. If the cap were to fail
mobility of contaminants in soil would not be reduced. Instead,
~I"\;'I~ t.'I':'I)'~ ,...;~,..'\te off-site via the unnamed stearn. Long term
=&:nte~~~=e of the cap would be required and the potential exists
for future costs and potential significant public health and
environmental risks if the cap were to fail.
~his alternative would not reduce the toxicity or volu~e of soil
contamination and does not utilize treatment as a principal
element. This alternative does not address the full extent of
the contaminated deep bedrock groundwater and therefore does not
reduce the toxicity, mobility or volume of those contaminants.
The contaminated sediments in the unnamed stream and water
hazards would not be excavated. Therefore, this alternative also
would not reduce the toxicity, mobility or volume of the
sediments in the unnamed stream and water hazards.
This aiterr.ative is not supported by the state. Some members of
the community favor capping to address soil contamination; others
favor an active collection system instead of a passive collectio~
~ystem to address groundwater contamination.
Approxi~ate Present Worth Cost:
$5,100,000
3. S.:&'-3
Contain~ent/Active Collection
Installation of a Cap; Diversion and Lining of a Portion of the
Unnamed Stream; Active Groundwater Collection; Groundwater
Treatment; and Environmental Monitoring.
This alternative is similar to Alternative SA-2 except that an
active groundwater collection system consisting of bedrock
extraction wells located adjacent to the pits would be
implemented, instead of a passive collection system. The
treatment system for the collected groundwater would be the same.
The benefits and/or limitations of SA-2 are applicable for SA-3
with the exception that the active groundwater collection system,
would significantly reduce the toxicity, mobility or volume of
contaminants in the on-site bedrock groundwater. Therefore, this
alternative does address the more highly contaminated groundwater
in the deep on-site bedrock although. as in ~ll site
alternatives, this alternative does not address contamination
that exists in the deep bedrock fractures off-site. This
'alternative is not supported by the state.
Approximate Present Worth Cost:
$5,800,000
4.
SA-4
~ ~ .- .- --- -'-" -... . ."..- ".--'-. --- .-.----- -~----'--------- ~ -.-
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27
Contain~gD~Treatrnent/Passive Collection
Excavation, Solidification and On-site Disposal of Cor.ta~inated
~"i': 1;Yc~Yat:i"n, D~.....atering, Solidification, and On-site
Disposal of Conta~inated Sediments from the Unnamed stream and
Golf Course Water Hazards; Construction of an Impermeable Cap:
Diversion and Lining of a Portion of the Unnamed Stream: Passive
Ground~atcr Collection: Groundwater Treatment: Wetlands
Restoration: and Environmental Monitoring.
Under this alternative, the more highly contaminated subsurface
soils will be remediated to a 10.4 direct contact present risk
level, while surface soils will be remediated to a 10.5 present
risk level. Excavation and solidification of contaminated soil
will reduce public health and environmental risks associated with
exposure to contaminated soils and will significantly minimize
the potentiGl for contaminated soils to migrate off-site via the
acjacent surfac~ waters. Construction of an impermeable cap will
pro\'ide a barrier to reduce exposure to and to minimize further
migration of contaminated 50i1. Both methodologies
(solidification, capping) are easily implementable and utilize
materials that are readily available. This alternative would
also reduce risks posed by PCB-contaminated sediments in the
unnamed stream and golf water hazards and by the contaminated
.groundwater seeps, overburden groundwater and a portion of the
bedrock aquifer.
This alternative is not effective in reducing the long term risks
ass~=iated with the deep on-site bedrock aquifer which contains
the sr~~t~st c~nce~trations of groundwater contaminants.
Therefore, there ~ill be no reduction in the toxicity, mobility
or volume of contaminants in the deep bedrock aquifer. The
combination of solidification of soils and sediments and capping
of the site will significantly reduce mobility of contaminated
soils, but will not reduce the toxicity or volume of contaminated
soils.
Aooroximate Present Worth Cost:
$8,300,000
S. SA-S
Containment/TreatmentLActive Passive Collection
Excavation, Solidification and On-site Disposal of contaminated
Soil; Excavation, Dewatering, Solidification and On-site Disposal
of contaminated Sediments from the Unnamed Stream and Golf Water
Hazards: Construction of an Impermeable Cap; Diversion and Lining
of a Portion of the Unnamed Stream: Passive and Active
Groundwater Collection; Groundwater Treatment; Wetlands
Restoration; and Environmental Monitoring.
This alternative has been chosen as the selected remedy for the
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28
site and is described in'detail in section X.
hDDroximate Present Worth Cost:
$1.0,100,000
6. SA-6
Treatr.ent/Passive Collection
In-situ Vitrification of Soils: Solidification of Sediments:
Diversion and Lining of a Portion of the Unnamed Stream: Passive
Ground~ater Collection; Groundwater Treatment: Wetlands
Restoration: and Environmental Monitoring.
Alternative SA-6 is primarily a treatment alternative utilizing
innovative technologies; in-situ vitrification (ISV) for
contaminated soils and solidification for contaminated sediments.
Specifically, all soils up to a 10.6 present risk level would be
vi~=ified in-situ. PCB-contaminated sediments above lower value
SQCs in surface waters would be excavated, solidified and
disposed of on-site. Affected wetland areas would be restored to
the maximum extent feasible. The passive collection system woulq
also be -installed to collect and treat the groundwater seeps,
overburden groundwater and shallow bedrock groundwater.
In-situ vitrification would be effective in the long term in
pe~anently reducing the toxicity and mobility of trea~ed soils.
Solidification would reduce the mobility of approximately 67,300
cubic yards of contaminated sediments. The passive groundwater
collection and treatment system would reduce the toxicity,
mobility and volume of groundwater contaminants in collected
groundwater. All three treatment technologies (ISV,
solidification, groundwater treatment) are considered innovative.
Contractors for the ISV technology are not readily available, and
thus this alternative is not easily implementable. Furthermore,
the vitrified matrix may restrict future land use of the site
(i.e. soccer field). This alternative provides significant
reduction of risks from exposure to contaminated soils, sediments
and seeps, but does not address, to the maximum extent
practicable, the deep on-site bedrock aquifer which contains the
greatest concentrations of groundwater contaminants. As with SA-
4, this alternative would not reduce the toxicity or volume of
contaminated sediments and tr1e toxicity, mobility or volume of
conta~inants in the deep bedrock aquifer. This alternative has
not received state acceptance and none of the comments received
during the public comment period support this approach.
Approximate Present Worth Cost:
$51,300,000
7.
SA-7
" .. ...-. -.
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29
~c~~ain~p-nt/Treatrnent/Active Collection
Excavation, Solidification and On-site Disposal of Contaminated
Soi!: Ex=av~~icn, Dewatering, Solidification, and On-site
:i:.~:::;=.:::l .=! ~':':1t?lrninated Sedir.tents; Construction of an .
Ireperrneable Cap; Diversion and Lining of a Portion of the Unnamed
Stream; Active Groundwater Collection; Groundwater Treatment;
~etlands ~estoration; and Environmental Monitoring.
This alternative is similar to SA-4 except that a much greater
volume of soils (10.6 present risk level) and sediments would be
treated and an active extraction bedrock collection system would
be utilized instead of a passive collection system. Excavation
and solidification of a larger volume of contaminated soil would
reduce public health and environmental risks associated with
exposure to contaminated soils and would significantly minimize
the potential for contaminated soils to migrate off-site.
Construction of an i~per~eable cap would provide an additional
barrier against soil exposure and migration. Both methodologies
(solidification, capping) are easily implementable, and utilize
materials that are readily available. This alternative would
further reduce risks posed by PCB-contaminated sediments and by
contaminated groundwater in the on-site overburden and bedrock
aquifers.
As with SA-4, this alternative would not reduce the toxicity or
volume of contaminated soils and sediments. This alternative is
acceptable to the state. However, no public comment was received
favoring treatment of this larger volume of soils and sediments.
This alternative is significantly more expensive than the
selected alternative.
Approximate FTesent Worth Cost:
$18,100,000.
8. SA-8
contai~ment/Treatrnent/Active Collection
Excavation, Incineration and On-site Disposal of Soils and
Sediments; Construction of an Impermeable Cap; Diversion and
Lining of a Portion of the Unnamed Stream; Active Groundwater
Collection; Groundwater Treatment; Wetlands Restoration; and
Environmental Monitoring.
This alternative has treatment as its principal element for site
soils to 10.6 present risk level, sediments to lower value SQCs
and the on-site bedrock aquifer. On-site incineration would
reduce the mobility, toxicity and voluce of contaDinants in soils
and sediments and the active collection/treatment groundwater
system would ~educe the mobility, toxicity and volume of
contaminants in the on-site bedrock aquifer. This alternative
utilizes a destruction technology (incineration) which is readily
.- .. ....-----... .
. -----_.- .'--.-
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30
available. Thus, implementation of this alternative would be
effective in reducing public health and environmental risks posed
by contaminated soils, sediments and groundwater.
Althcu;h thi3 alter~ative would result in a significant reduction
of risk, SA-8 as well as all other alternatives, would not be a
pe~anent remedy because of the untreated wastes contained within
the pits which will continue to act as a contaminant source.
Long-term monitoring and maintenance would still be required.
Finally, high lead soil concentrations (maximum 4650 ppm) may
result in exceedance of ar.~ient air levels due to excessive lead
emissions emitted during incineration.
Ap?roxi~at~ Present Worth Cost:
$8a,000.000. .
x.
'I'ID: B!:I,ECTED REMED'l
The selected remedial action consists of source control and
management of migration components listed in Section VII but
excludes action on Middle Mars~ which will be addressed as an -
operable unit. A comprehensive approach is necessary in order to'
achieve the response objectives established for site remediation
and the governing. legal requirements.
A.
Description of the Selecte~ Reme~y
After evaluating all of the feasible alternatives, EPA is
selecting a nine-component plan to address soil, sediment and
groundwater contamination at the SL site:
1.
site Preparation
The site preparation work includes the establishment of
sec~ritiT and controlled access to the site, the connection
of light and power utilities and the furnishing of sanitary
facilities. A chain link fence ~ill be constructed around
the perimeter of the site and designated off-site areas
expected to include the groundwater treatment facility,
areas of excavation, and additional areas defined during
remedy design. To the maximum extent feasible, the existing
fence will be utilized. Warning signs will be posted at 100
foot intervals along all fences and at the entrance gate.
Areas to be remediated will initially be cleared of
. "..----.....' .---........---
_.~. -,.--,--"",-."." .-.-
-.. ._.... .o.
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31
vegetation and debris. Most of these materials will be re-
di~posed of on-site. cobblestones that will be disposed of
off-site will be sampled for residual contamination. If
PCBs are detected, the debris will be decontaminated, upon
evaluation of the cost effectiveness by the EPA, with an
approved physical removal process (i.e. scrub/wash/steam-
clean or sand blast/steam-clean). After areas have been
cleared, grading will be performed to provide areas for
re~edial operations, staging and to promote controlled site
drainage.
Runoff controls will be developed in accordance with the
conceptual design presented in Figure 5, and as discussed in
section 10 of the FS. Components will include drainage
ditches on the western and southern site boundaries, a new
sedimentation basin and dikes constructed adjacent to the
eastern and northern boundaries of the site's disposal area.
Erosion and sediment control measures used during the
construction period are also considered part of the site
preparation work.
2.
soil Excavation/Treatment
This component is composed of the following: excavation,
grading, solidification, on-site disposal, backfilling,
predesign work and implementation monitoring. A processing
area will be set up at the site prior to soil excavation.
All on-site unsaturated soils contaminated above the soil
cleanup levels described in section X.B.l.a., including
soils within the 100-year floodplain, will be excavated (see
Figure 6-4 RI). Off-site soils contaminated above target
levels described in section X.B.l.b. will be excavated from
areas shown in Figure 6. Bulk debris will then be screened
out of the excavated materials. Screened-out debris will be
disposed of on-site. All debris disposed of on-site will be
contained within waste cells fomed out of compacted
solidified product or within excavated areas and ultimately
covered. All excavated soils contaminated above 50 ppm of
PCBs and/or 30 ppm of PAHs will be placed, along with a
hardening agent, in a mixing unit for solidification. The
solidified material will then be disposed of on-site beneath
the proposed landfill cap, above the existing ground surface
and outside the lOO-year floodplain. Coordination between
the i~plementation of the solidification processes and cap
construction will be necessary to avoid extended exposure of
solidified material. Excavated areas on-site within the
boundaries of the cap may be backfilled with clean fill,
excavated off-site soils containing between 10 and 50 ppm of
PCBs and/or debris generated during site preparation and
excavation. For excavated areas beyond the boundaries of
the lan~fill cap, final restoration will consist of
backfilling with clean fill, grading, loaming and seeding.
. - .,,,,,,-'"'-.'''
._--~ .,,--~--'--'-"'- ....----.
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32
~ns~turated soils with contaminants above the cleanup
levels, as defined in Section X.B.l., will be excavated.
Or.-si~e. the volume and area of soil to be excavated is
sho~n 1n Figure 6-4 of the Phase II RI, and is estimated at
2~,200 ~ubic yards. The volume to be excavated off-si~e
will be defined by predesign sampling. The unsaturated zone
at tha site is defined as that area from the surface
elevation to the seasonal low groundwater table.
Predesign work includes off-site sampling, defining the
unsaturated zone and solidification treatability studies.
Off-site areas to be sampled are shown in Figure 6 and
described below:
1.
East of the existing fence along the eastern boundary
of the site, from the southern boundary of the site to
the Hathaway Road culverts. This area includes the
east and west banks of the portion of the unnamed
stream along the eastern border of the site.
Just north of Hathaway Road and south of the
intermittent tributary to the unnamed stream witpin the
golf course.
The sampling program will determine the nature and extent of
PCB contamination in surface and subsurface soils in the
unsaturated layer in the above referenced areas. Based on
the sampling data, areas with soil contaminants in excess of
10 pprn of PCBs and of 50 ppm of PCBs will be defined. The
seasonal low groundwater elevation will be defined by
implementing a monitoring program that will evaluate the
fluctuation of the water table. This program will monitor
the fluctuation for all four seasons, but with particular
focus on the summer months. Bench-scale testing of the
solidification process using representative soil and
sediment samples ~ill be performed to evaluate solidifying
agents and mixtures. EPA is specifically requesting that
treatability tests include the mixing of lime with soils.
Testing to determine appropriate and optimal use of
hardening agents will consist of leachability tests. EP
toxicity tests will also be performed to determine whether
certain soils will be RCRA - characteristic waste after
solidification.
2.
An air monitoring program will be implemented during the
performance of the on-site and off-site soil excavation and
treatment component of the remedy to determine risks to on-
site workers and nearby residents. Air sampling stations
will be located at representative points throughout the site
and at the perimeter of the site. Samples will be analyzed,
........ .". ..._._--_.~----
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33
at a minimum, for VOCs, PCB in vapor phase and PCB
particulates. To limit potential air emissions the
following methods may be implemented: enclosure of the
~reas: e~ission suppression techniques (ie. foam, water
~pray); and containment of excavated soils.
_"ork
EPA anticipates that some amount of off-site wetlands areas
will be i~pacted by soil excavation. For those areas, steps
will be taken as described in component 7, to minimize
potential destruction or loss of wetlands or adverse impacts
to organisms.
Upon completion of the excavation of on-site and off-site
soils, samples will be collected and evaluated against the
cleanup levels for soils (see section X.B.l). These samples
will be used to evaluate the success of excavation.
3 .
Sediment Treatment
The sedim~nt component is composed of: preparation work,
excavationjd=edging, dewatering, transportation,
solidification and disposal. Initial preparation work will \
include construction of roadways and, where needed, clearing
of trees and shrubs. Cleared materials will be disposed of
on-site. Initially, sediments from the designated areas
shown in Figure 6 will be excavated to a depth of one foot.
Dewatering of excavated sediments will be performed (i.e.
fLlter presses) to reduce sediment moisture content.
Effluent from the dewatering operation will be treated to
comply with state water quality standards, as discussed in
section X.B.3.c. Presently, the EPA expects that activated
carbon or the on-site treatment plant will be used to comply
with these stan~ards. Treated effluent will be discharged
to the unnamed stream. After the dewatering process, the
dewater~d sediments will be solidified and disposed of on-
site above the existing groundwater surface, as described in
the preceding section.
An estimated 1,900 cubic yards of sediments in excess of the
sediment cleanup levels, as described in Section X.B.2.,
will be excavated or dredged and transported to the site's
lan~fill area. Areas to be excavated are shown in Figure 6
and described below:
a.
Unnamed stream and tributaries from areas south, east
and north of the site to the golf course water hazards
The first water hazard north of the unnamed stream and
a portion of the next water hazard.
b.
EPA shall determine when excavation activities will be
--~~.
~- .--- -----..--- ._-~ .
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34
performed upon evaluating weather conditions, stream flow,
scneduling constraints, and the impacts of construction
actjvities on the golf course. Excavated areas will be
j~clatEd by means of erosion and sedimentation control
devices (i.e. sedimentation basin) and diversion structures
to limit the resuspension of contaminated sediments.
Methods such as sedimentation basins and/or silt curtains
~ill also minimize the amount of contaminated sediments
moving downstream during dredging. During excavation of
PCB-contaminated sedi~e~ts, do.~stream monitoring of surface
water will be conducted to ensure that transport is not
occurring as a result of the excavation.
An air monitoring program will be performed during the
implementation of this component to monitor risks to on-site
workers and nearby residents, as described in the soil
treatment component of the remedy. Mitigative measures,
such as those discussed in the preceding section, shall be
taken during excavation, transport and treatment to control
emission.s.
For wetlands areas affected by sediment excavation, steps
will be taken as described in component 7, to minimize
potential destruction or loss of wetlands or adverse impacts
to organisms.
Aft~r the initial excavation of sediments, sediment sampling
of the excavated areas will be performed to ensure
compliance with the sediment" target level. Sediment samples
will be analyzed for PCBs and TOC. These samples will be
use'~ to evaluate the success of excavation/dredging. Based
on the sampling results as well as field judgement,
additional excavation at one foot depth intervals shall be
performed in any area where sediment contaminant levels are
equal to or greater than the sediment target level.
4.
Construction ot an Impermeable cap
The purposes of the impermeable cap are to reduce human and
animal exposure to the solidified soils and sediments, to
reduce exposure to untreated contaminated soils and wastes
within the pits, and to reduce the amount of precipitation
that could filt~r through the waste and carry contaminants
into the groundwater and away from the capped area.
This component is composed of the following: grading,
backfilling, capping, predesign work and implementation
requirements.
As described under the site preparation component, the first
step in constructing the cap will be to remove the trees and
brush from the site's surface area. Excavated areas will be
.-.. '. --.----.-
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35
backfilled and the site regraded prior
of the solidified soils and sediments.
cap will then be constructed on top of
~~d ~~di~~nt layer.
to on-site disposal
The layers of the
the solidified soil
The detailed design of the cap will be finalized during the
design phase of the remedy to meet the performance standards
set forth in the Massachusetts Hazardous Haste Regulations,
including the requirement that the clay layer have an
average permeability of 10.7 cm/sec. Based on the
conceptual design described in Section 10 of the Feasibility
study, the cap will consist of four layers (see Figure 7).
The base of the cap will consist of a two-foot clay layer of
an average permeability of 10'7 em/sec. To protect the clay
layer from the effects of frost, an lS-inch buffer layer of
soil will be installed above the clay layer. A permeable
drainage layer, consisting of 12 inches of sandy soil will
then be placed above the buffer layer. Water that passes
through the upper layers of the cap will drain off to the
sides of the cap, over the buffer and clay layers. This
water will be collected in drains around the edge of the
cap, and discharged to the unnamed stream. Above the
drainage layer, a 2-foot vegetative layer will be installed
consisting of 18 inches of sandy soil and 6 inches of
topsoil. Grass will be planted in the topsoil. .
The cap will be constructed over a projected ll-pcre area
extending over the total surface area of the site with the
exception of the area within the loo-year flood plain (see
Figure 8). As discussed under the second and third
components of the se1ected remedy, the cap will be
constructed over the contaminated surface soils and
sediments that will be solidified and placed on-site. The
cap will also cover unsolidified soils within the ll-acre
area that may contain contaminants below the cleanup target
level.
Predesign studies will consist of permeability testing of
clay mixtures to determine the optimal clay mixture for
compliance with the design requirements of a 10.7 em/see
permeability. Both lab and field patch tests will be
performed to check compliance with requirements.
Implementation requirements ~ill include erosion and
sediment control ~easures, as discussed in component 1 (site
preparation) of the selected remedy. Erosion which may
occur during the vegetation establishment will be controlled
by applying hay bales or erosion control fabrics. site
regrading of the northeastern corner of the site, within the
loo-year flood plain of the unnamed stream, will be limited
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36
to backfilling areas where soils have been removed for
trea~~ent. Construction activities will be performed to
minimize disturbance of contaminated soils. Furthermore,
fu~itivc d~~t ~ill be controlled during con5t~ctic~
activities by water sprays or dust control chemicals.
5.
Diversion and Lining of the Unnamed stream
This component of the selected remedy is limited to the
portion of the unnamed stream parallel to the eastern
boundary of the site. This component consists of the
following: limited clearing of areas adjacent to the
unnamed stream portion, temporary diversion of surface
waters, excavation of sediments, concrete lining of the
stream portion, red~version of surface waters.
Initially, only those areas necessary for implementation and
construction of this component will be cleared of shrubs and
trees. Cleared material will be disposed of on-site within
excavated areas. Surface waters of the portion of the
stream to be lined with concrete will be temporarily
diverted until the concrete channel is constructed and the
surface waters can be redirected back through the new
channel. The whole length of the unnamed stream and its
tributaries up to the first and second ~ater hazards will be
excavated to re~ove the contaminated sediments (see Figure
6). Next, the portion of the unnamed stream parallel ~o the
eastern border of the site will be lined with concrete to
form a concrete channel. The concrete channel will prevent
the ~aters of the unnamed stream from being pulled into the
extraction wells described in the next component. The
concrete channel will be constructed with a series of
baffled sections to reduce stream velocities and maximize
sediment deposition. After completion of the concrete
lining, the unnamed stream will be directed back to the new
channel.
Figure 5 shows the portion of the unnamed stream which will
be excavated, diverted and lined. This portion of the
stream is approximately 750 feet in length from the culverts
at the southern boundary of the site up to the culverts at
Hathaway Road.
The method of stream diversion will be finalized during
design of the selected remedy. In view of the need to
mitigate wetland impacts, EPA has determined that the
diversion method of digging a temporary trench on the east
or west bank of the unnamed stream will be re-evaluated
during remedial design. If deemed feasible, the portion of
the unnamed stream to be contained within the concrete
- - --..... .~.- . -------..
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37
channel will be diverted and/or pumped through a te~porary
pipe located in close proximity to the existing streambed.
Tha stream diversion structure and ancillary activities will
ta pe~:~~~d to mitigate adverse i~pacts to the wetlands, as
described in component 7 of the selected remedy.
Collection and Treatment of On-site Groundwater
6.
with this component of the preferred alternative, EPA will
cOIT~ine two phases of groundwater collection: active
groundwater collection and passive groundwater collection.
A.
Active Groundwater Collection
This component is composed of the following: predesign pump
tests: extraction wells: hydrofracturing or blasting (to
increase hydr~ulic ccnnection with the pits): groundwater
pumping; groundwater treatment and groundwater monitoring.
Approximately 6 deep bedrock extraction wells at least six
inches in diameter will be installed to depths as great as -
200 feet. The cumulative pumping rate is expected to be 30 \
to 60 gallons per minute. A conceptual location map is
presented in Figure ll-7(FS). The specific number, depth,
pu~ping rates and location of the extraction wells will be
defined during' design as directed by predesign
investigations. The wells will be located as close as
possible to the quarry pits so they are hydraulically
connected to the pits. Hydrofracturing or blasting may be
performed on individual boreholes to supplement the
hydraulic connection between the boreholes and the pits.
During design the extent of hydrofracturing or blasting will
be defined as directed by predesign investigations.
Treatme~t of the extracted ground water is discussed in
S~ction X.A.6.C.
Predesign work includes pump tests, groundwater sampling and
subsurface exploration to define pit boundaries. Pump tests
will be performed to determine well yields. This
information will be used to evaluate the extent to which
hydro fracturing or blasting will be used and to define the
safe yields for individual wells. Consideration of
extracted groundwater disposal and impacts of surrounding
wetlands (ie. dewatering) will be incorporated into pump
test design. In addition, as part of the predesign program
associated with the pump tests, subsurface investigations to
refine the present delineation of the quarry pits will occur
to assist in locating extraction wells.
Groundwater monitoring of the overburden, shallow and deep.
bedrock will occur during the implementation of the active
groundwater collection system. Chemical concentrations and
.----...., . - .---.--- "
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38
water ~J.2vations will be monitored to evaluate the
efficiency of the extraction system. The frequency of
monitoring will be finalized during design; however, it is
~:~~=~:= ~~~t ~onitoring wells will be sampled on a
~~arterly s=he1ule. The specifics of this monitoring
progra~ will be defined during design but, at a minimum,
will include the multilevel Westbay Systems installed during
the Remedial Investigation. In addition, pumping rates of
each well and the treatment and extraction system influent
and effluent concentrations will be monitored with the
objective of defining the mass of contaminants extracted
over the life of the system.
Once th~ clean up targets, as defined in Section X.B.3.a.,
have been satisfied, the extraction wells will be shut down
and a monitoring program will be implemented to confirm the
results. This program will, at a minimum, consist of three
years of quarterly ~onitoring of ground~ater quality.
Monitoring wells to be sampled will be identified in the
overburden and deep and shallow bedrock. These wells will
be ~ells that had been historically monitored during the,
operation of the extraction system. Additional specifics of
this monitoring program will be defined in the remedial
design. The results of this monitoring will be reviewed by
the EPA to evaluate the success of the extraction system and
determine if and when it should be reimplemented. The
mQnitoring results from this program ultimately serve two
purposes: first to evaluate the success of the remedy and
second to help define the extent of the institutional
controls.
B.
Passive Groundwater Collection
This component of the remedy is composed of the following:
cy.cavation; installation of the underdrain pipe; and water
treatment and monitoring. The excavation depth for the
underdrain installation will extend to the top of the
bedrock surface. The underdrain itself will be composed of
a l2-inch slotted pipe wrapped in geotextile fabric and
backfilled in graded stone (see Figure ll-2A FS). The
expected flow rate for the underdrain pipe is approximately
35 gallons per minute. Specifics of the underdrain will be
defined in the remedy design and modified depending on
predeslgn data. The location of the underdrain will also be
defined in the re~edial design, but presently it is expected
to be located just beyond the cap boundaries as shown in
Figure 11-3 (FS). Treatment of the extracted water is
discussed below in section X.A.6.C.
Predesign work is the same for the passive system as it is
for the active system. Of specific note are the pump tests
performed in conjunction with the active groundwater system.
-------
- -.- .--------
39
These results will define the impact of the active system on
overburden flow and help define expected flow rates for the
passive system.
Installation of the passive system will be impacted by the
i~plementation of the cap and the active ground water
extraction system. Since the underdrain is to be installed
at the boundary of the cap, the time of its installation
will depend upon that of the cap. Consideration of the
appropriate implementation sequence of these components of
the remedy will be given in the remedy design.
Monitoring of the flowrate and sampling and analysis of the
water collected by the passive system will occur before and
after treat~ent, at a minimum on a quarterly basis, with the
objectives of defining the mass of contaminants removed by
the system and compliance with the effluent limitations and
ground~ater target levels. Additional specifics of
rnonitori~g frequency and sampling parameters will be defined
during remedial design.
Once the clean up target levels as specified in Section
X.B.3.b., have been satisfied for two years, treatment of
collected groundwater within the passive system will" not be
required; i~stead, monitoring will be implemented. The.
results of this monitoring will be reviewed by the EPA to
determine if and when the passive collection system should
be rei~plemented.
C.
Groundwater Treatment
The proposed groundwater treatment for both the active and
passive collection systems consists of the following: bench-
scale and pilot studies; oxidation/filtration for metals
removal: ultraviolet (UV)/ozonation for organics removal and
groundwater monitoring.
Chemical oxidants (i.e., potassium permanganate), combined
with aeration and followed by filtration, will remove
metals. Solids produced during the oxidation step will be
concentrated and dewatered prior to disposal. If these
solids are hazardous, they will be disposed of in a RCRA
landfill. All hazardous wastes transported off-site will be
done in accordance with RCRA and DOT regulations. .
EPA has selected UV photolysis/ozonation as the water
treatment component for organics. This is because
UV/ozonation is an innovative treatment technology that
destroys organic compounds in water through a combination of
UV light and a mixture of ozone and hydrogen peroxide. A
unit attached to the reactor collects any residual ozone and
converts it to oxygen. UV/ozonation is a destruction
---
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40
technology and, therefore, will not require disposal of
w~st~ r~sidua1s. Treated groundwater will be discharged to
the unnamed stream or, if deemed feasible, to the New
Bedf~~d ~econdary treatment plant.
UVjozonation is an innovative technology which has been
proven to be effective in the destruction of organic
conta~inants in groundwater. However, it will be necessary
to conduct bench-scale treatability studies to determine the
imp1ementabi1ity of this technology on site-specific
contaminants. If UVjozonation, based on the results of the
treatability studies, is not determined to be implementable
or effective or is determined to be significantly more
costly than other effective treatments, then EPA will select
air-stripping with GAC and vapor phase carbon as the
treatment technology for removal of organics in groundwater.
Since the levels of groundwater contaminants at the site are
relatively high, and because UVjozonation is an innovative
treatment, pilot testing of UVjozonation (if selected) will
be re~ired to determine the implementabi1ity of the -
ground~ater treatment system on a full-scale level. The
pilot study will yield information on the percent reduction
of organic and inorganic compounds in groundwater and the
volume and types of residuals and byproducts produced by the
operation of the treatment system.
Monitoring of the flow rate and chemical analysis of
groundwater entering and leaving the full-scale treatment
plant will be evaluated during the operation of the
treatment system to ensure that response objectives and
effluent limitations are achieved. .
The period of operation of the treatment plant will be
determined by the achievement of the completion requirements
specified for the active and passive systems. During the
operation of the treatment plant, regardless of what
technology is chosen, the effluent will have to comply with
the effluent limitations, as described in Section X.B.3.c.
7.
Wetlan4s Restoration/Enhancement
EPA has determined that there are no practicable
alternatives to the soil excavation, sediment excavation and
stream diversion and lining components of the selected
remedy, that would achieve site goals but would have less
adverse impacts on the aquatic ecsoystem. The contaminants
in the soils and sediments would continue to pose
unacceptable human health and/or environmental risks if
excavation of the soils and sediments greater than the
target levels were not performed.
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41
Ey.c~vation of contaminated sediments and soils, lining of
the stream and any ancillary activities will result in
unavoidable impacts and disturbance to wetland r~source
areas. S~ch i~pa=ts may include the destruction of
vegetation and the loss of certain plant and aquatic
organisms. Impacts to the fauna and flora will be mitigated
as discussed below.
During implementation of the remedy, steps will be taken to
minimize the destruction, loss and degradation of wetlands,
including the use of sedimentation basins. A wetland
restoration program will be implemented upon completion of
the remedial activities in wetland areas adversely impacted
by remedial action and ancillary activities. In particular,
the unnamed stream portions north of Hathaway Road will be
restored to reasonably similar hydrological and botanical
conditions existing prior to excavation. The concrete
channel which will line the unnamed stream along the eastern
boundary of the site will be constructed with a series of
baffled sections to reduce stream velocities and maximize
sediment deposition. Any additional wetland areas impacted
by dredging and/or associated activities, including wooded -
areas to the north and east of the site, will be restored
and/or enhanced, to the maximum extent feasible.
The restoration program will be developed during design of
the selected remedy. This program will iden'tify the fa'ctors
which are key to a successful restoration of the altered
wetlands. Factors may include, but not necessarily be
limited to, replacing and regrading hydric soils, provisions
for hydraulic control and provisions for vegetative
reestablishment, including transplanting, seeding or some
combination thereof.
The restoration program will include monitoring requirements
to determine the success of the restoration. Periodic
maintenance (i.e. planting) may also be necessary to ensure
final restoration of the designated wetland areas.
8.
Long-term Environmental Monitoring and rive-Year Reviews
For the reasons discussed in Section X.B.3., EPA considers
it technically impracticable to clean the contaminated deep
bedrock groundwater both on- and off-site to drinking water
standards. Accordingly, a groundwater monitoring program
focusing on deep bedrock groundwater and off-site overburden
and bedrock groundwater will be implemented. The groundwater
monitoring program will be designed for the following
purposes:
a.
to document the changes in contaminant concentrations
---.-- ._,~_.__.-
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42
b.
c.
ove-r t5.me~
to evaluate the success of remedial action~ and
to help define the extent of institutional controls.
Eec~u:e wa~tes in the pits would be left untreated, although
capped, groundwater monitoring of wells adjacent to the pits
will also be performed to determine changes in contaminant
lOQding: and/or distribution.
The details of the on-site and off-site overburden and
bedrock groundwater monitoring program will be developed
during remedial design. The monitoring program will be
tailored to site specific hydrogeologic conditions and
contaminants. Wells will be sampled on a routine basis to
evaluate dispersion of the contaminant plume and the
distribution of contaminant migration. A list of a
representative subset of approximately 50 existing
~onitoring ~ells to be ~onitored periodically will be
generated. The frequency of monitoring will be finalized
during design~ however, it is expected that monitoring wells
will be sampled and analyzed on a quarterly basis to improve
the existing data base and establish contaminant '
concentrations. The proposed groundwater monitoring program
will include sampling of the-four existing multi-level
bedrock wells (ECJ-l,2,3,4) during every sampling round.
Five to eight zones will be sampled in each of the multi-
l~vel monitoring wells. Maintenance requirements will -
include replacement of the multi-level monitoring wells.
During design, the condition and usefulness of existing
wells will be checked and compared with future data needs.
Recommendations on the installation of additional multi-
level, overburden and/or bedrock monitoring wells will be
specified during remedial design if deemed necessary to
adequately monitor over a long term the nature and extent of
groundwater contamination. Initially, all samples will be
analyzed, at a minimum, for VOCs, SVOCs, PCBs and metals.
Specific parameters may be added or deleted depending on
sampling results and observed trends.
Environmental monitoring will also include sampling of
sediments in the unnamed stream to indirectly check the
integrity of the cap and solidified material in preventing
mobility and transport of PCBs and PARs. At a minimum,
sediment samples will be initially monitored for PCBs,
SVOCs, and total organic carbon.
All monitoring data will be formally reviewed and evaluated
during the operation of remedial action to ensure that
appropriate remedial response objectives are achieved.
Monitoring frequency and chemical parameters may be added or
deleted based on review of monitoring data. Five-year
reviews will be initiated to ensure that human health and
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43
the environment are being protected by the re~edial action
being implemented. Future remedial action, including source
control measures, will be considered if the environmental
~~nit~ring program determines that unacceptable risks to
human health and/or the environment are posed by exposure to
sit~ contaminants.
9.
Institutional Controls
Because the bedrock groundwater cannot be cleaned to
drinking water standards and because wastes will remain in
the pits, institutional controls will be necessary to
achieve long term protectiveness. Institutional controls at
this site will be designed: (i) to ensure that groundwater
in the zone of contamination will not be used as a drinking
~ater source; and (ii) to ensure that any use of the site
will not interfere with the effectiveness of the cap in
reducing exposure to contaminants. EPA will work with state
and local officials to enact ordinances and zoning
restrictions to prevent the use of groundwater for drinking
water and to place deed restrictions regulating land use at .
the site. The effectiveness of the institutional controls
will be re-evaluated during the 5-year reviews described
above.
B.
Target Levels
Based on results of the Phase I and Phase II risk assessments,
target levels were developed for the following media: soils,
sediments, groundwater.
1.
Soil Target Levels
a.
Soils within the Disposal Site
Soil target levels for soils located within the 12-acre
disposal area were derived for PCB and PAR compounds. The
target levels for PCBs are based on total Aroclors, while
PARs are based on total carcinogenic PARs (these include
benzo(a)anthracene, benzo(b) fluoranthene,
benzo(k)fluoranthene, benzo(a)pyrene, .chrysene,
dibenzo(ah) anthracene, and indeno (1,2,3-cd)pyrene.
Soil taroet levels for PCBs and PAHs are based on risks
associat~d with direct contact to, and incidental ingestion
of, indicator compounds detected in surface soils and test
pit soils. The assumptions used to calculate soil target
levels reflect the site zoning designation and current and
future uses of the site. The current zoning for the site is
commercial and access to the disposal area is restricted.
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44
the population is not expected to significantly increase.
Two future land use scenarios for this land have been
proposed: a parking lot or a soccer field.
Based on current land use at the site, target levels for
PCBs and PARs were estimated. Exposure parameters
considered in the target level calculations were as follows:
.
exposure by an older child (8 to 18 years)
4S-kg body weight
12 exposures per year (twice per month from May through
october)
la-year exposure duration
4 grams of soil contacted (represents arms, hands, and
lo~er legs)
relative absorption factors for PCBs and PAHs of 7
percent (dermal)
ingestion of 0.1 grams of soil per exposure
relative absorption factor for PCBs and PAHs of 50
percent (oral)
.
.
Because one of the possible future uses for this disposal
area is a soccer field, target levels for PCBs and PAHs were
also estimated to be protective against exposure conditions
for this land use. It is assumed that concurrent exposure
through direct contact and ingestion of soil occurs per
exposure event. Exposure parameters considered for these
calculations include the following:
.
exposure by an older child (8 to 18 years)
4S-kg body weight
48 exposures per year (twice per week from May through
October)
10-year exposure duration
4 grams of soil contacted (represents arms, hands, and
lower legs)
relative absorption factors for PCBs and PARs of 7
percent (dermal)
.
ingestion of 0.1 gram~ of soil per exposure
relative absorption factor for PCBs and PARs of 50
percent (oral)
The disposal area soil remediation component of the selected
remedial action entails excavation and treatment of soils
contaminated with total PCBs at concentrations of 50 ppm or
greater, and total carcinogenic PAHs at concentrations of 30
ppm or greater, located in the unsaturated zone. These
clean-up levels correspond to a 10.5 risk level under
current site use conditions and a 10.' risk level under
future site use conditions (soccer field) which falls within
.
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45
. .(, .7 . d
the target risk range of 10 to 10 conSl ered for
remediation at superfund sites. The potential risk will be
further Substantially reduced by the construction of an
jrnren!'A;\ry1p. cap above the treated soils thus minimizing
direct exposure to the contaminants. During the excavation
and treatment of soil, air quality will be monitored ~o
ensure that site specific ambient action levels are not
ex::ef:ded.
It is important to recognize the inherent uncertainties in
estimating the health-based soil cleanup levels.
Uncertainties are associated with the value of each exposure
parameter, the toxicological data base and the overall set
of exposure assumptions. Despite these uncertainties, EPA
believes that the assumptions used to estimate the cleanup
levels are reasonable, and that it is necessary to use this
approach, in order to ensure that the cleanup goals will be
adequately protective of public health.
b.
Soils outside the Disposal Area
Results of the off-site soil sampling program will be
analyzed to identify contaminant levels in unsaturated soils\
for areas specified in section X.A.2.
Incremental carcinogenic risks associated with exposure to
contaminated surface soil in areas outside the disfosal site
have been estimated wi thin the range of 10.5 to 10.. In
particular, incremental carcinogenic risks for adults
associated with dermal contact with soil outside the
disposal area containing contaminants of concern at the mean
and maximum concentrations were estimated at 2.7 x .10.7 and
4.9 x 10'7, respectively. However, results of a limited
number of soil sampling within the golf course were used in
the calculations of these risks. EPA has determined that
additional soil sampling is needed in areas immediately
north and east of the site's disposal area. Therefore, a
soil cleanup level for soils outside the disposal area has
been established because the additional sampling may show
greater contaminant levels than levels indicated in the RIs
and because corres?onding estimated risk values may be
greater than a 10. risk.
Unsaturated soils in areas outside the 12-acre disposal area
with PCB concentrations equal to or greater than 10 ppm will
be excavated, transported to and disposed of within the
site's disposal area. Unsaturated soils with PCB
concentrations equal to or greater than 50 ppm will be
solidified prior to disposal within the site's landfill
area, consistent with the cleanup level for soils within the
site's restricted disposal area, as described in the
preceding section.
-'---' ..--.--.--
------------------ .'
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46
The soil cleanup level of 10 ppm of PCBs for soils outside
the site's disposal area is based on a 10.5 incremental
cor.~c~ ~i~k a~sociated with direct contact with contaminated
soil. The cleanup level of 10 ppm is more st~ingent than
the soil cleanup level of 50 ppm for soils within the
l2-acre disposal area because soils outside the disposal
area are located in nonrestricted areas resulting in greater
frequency of exposure with these contaminated soils. In
addition, soils outside the disposal area will not be
covered with an impermeable cap which will cover the
majority of the site's disposal area thus further minimizing
exposure to the soils underlying the cap.
Excavated off-site areas will be backfilled with clean fill.
2.
Sediment Target Levels
The sediment target level for the unnamed stream, its tributaries
and the golf course water hazards is the interim mean sediment -
quality criteria (SQC) value of 20 micrograms of PCBs per gram of
carbon (ugjgC). This value for PCBs has been derived by the EPA \
Criteria and Standards Division to protect uses of aquatic life,
specifically the consumption of aquatic life by wildlife. The
mean sediment quality criteria (20 ug PCBsjgC) was chosen as the
cleanup level because:
a.
b.
c.
For total organic carbon (TOC) of 10 gCjkg sediment,
typically found in stream sediments, it represents the
detection limit for analyzing PCBs in sediments.
After remediation, the resulting PCB concentrations in
stream sediments represent levels which, with
approximately 50% certainty, will result in
interstitial water concentrations equal to or lower
than the PCB ambient water quality criterion (final
residue value of 0.014 ugjl).
Based on Toe sediment values between 10 gCjkg sediment
and 20 gCjkg sediment, calculated SQCs from between 0.2
ppm PCBs and 0.4 ppm PCBs, respectively, compare.
favorably with the toxicological literature which
documents examples of sublethal toxic effects in
aquatic organisms at PCB tissue levels and hence
sediment concentrations of less than 1 ppm and as low
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47
The following table lists projected mean SQCs in pprn of PCBs.
TOC (qC/kg sediment) Mean SOC Levels in ppm of PCBs
2 gCjkg sediment 0.04 ppm PCBs
5 gCjkg sediment 0.1 ppm PCBs
8 gCjkg sediment 0.16 ppm PCBs
10 gCjkg sediment 0.2 ppm PCBs
15 gCjkg sediment O. 3 ppm PCBs
20 gCjkg sediment 0.4 ppm PCBs
EPA considered two additional factors: the detection limit for
analyzing PCBs in sediments and background levels. The Contract
Lab Protocol (CLP) detection limit for the analysis of PCBs in
sediments is 0.16 ppm. The background PCB level at this site has
been estimated at approximately 0.14 ppm. Therefore, EPA has
cleterffiined that the sedir.ent target levels in ppm of PCBs for
sediments with TOC values less than or equal to 10 gCjkg sediment
will be 0.2 ppTh of PCBs. Where TOC values are greater than
10gC/kg sediment, the calculated mean SQC will be the target
level. Therefore, target levels are as follows:
Toe (qC/kq sediment)
Final Sediment Tarqet Levels in ppm
PCBs
2-10 gCjKg sediment
15 gC/Kg sediment
20 gCjKg sediment
0.2 ppm PCBs
O. 3 ppm PCBs
0.4 ppm PCBs
3.
Groundwater Target Levels
EPA has determined that conta~inants from the quarry pits have
contaminated. 01\- and off-site groundwater and surface water in
the unnamed stream. In particular, high levels of VOCs detected
in groundwater located in bedrock fractures indicate that pockets
of highly-contaminated liquid waste may exist within the pits and
along bedrock fractures. For this site, EPA considers it
technically impracticable from an engineering perspective to
clean up the contaminated deep bedrock groundwater to Maximum
contaminant Levels (MCLs) promulgated under the Safe Drinking
Water'Act, and Massachusetts Drinking Water Standards. The basis
for this determination of technical impracticability is discussed
in Section XI.B.
Instead of MCLs, EPA has determined that the cleanup goals for
gro~ndw~ter at this site are the significant reduction of
contaminant mass in the aquifer and the protection of local
surface water bodies. A two-part plan for cleanup of on-site
contaminated groundwater and seeps is presented. It involves an
active extraction system to collect contaminated groundwater
located in and adjacent to the pits and a passive collection
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48
~ qrDund~at~r treatment system would be operated to treat
collected groundwater.
~.
o~-:-t:' i..,,,," C~llection System Cleanup Levels
Aquifer)
(In the
The cleanup goal for the active collection system is the
significant reduction in the mass of bedrock contamination.
EPA will evaluate achievement of this cleanup goal by using
two criteria: (1) a concentration range of 1 to 010 ppm of
total volatile organic compounds (VOCs): and/or (2) an
asymptotic curve using groundwater monitoring data
indicating that significant concentration reductions are no
longer being achiev~d. The groundwater monitoring data
curve will be asymptotic when the rate of change in
contaminant levels approaches zero, with no statistically
significant deviation.
The£e t~o criteria will be evaluated together to determine
when a significant reduction of contaminants has occurred.
Given the complexities of the Sullivan's Ledge system, EPA
will modify the range of 1 to 10 ppm of total VOCs if
necessary upon review of actual full-scale treatment
performance data. Monitoring data will be reviewed to
assess the practicability of achieving or exceeding 1 t~ 10
ppm of total VOCs. This data will be evaluated against the
asymptotic curve star.jard by comparing contaminant
concentratio~s against time at a number of monitoring wel1s~
If new monitoring data indicates that either achieving the 1
to 10 ppm VOC concentrations is impracticable, or that
o achieving groundwater concentrations lower than 1 to 10 ppm
is practicable, then the ROD will be amended. The
as~.ptotic curve must be demonstrated for one year (four
consecutive quarters), at a minimum, during the operation of
the pumps before the pumps can be shut off. After the
shutdo~n of the active pumping system, monitoring data will
be evaluated on a quarterly basis for a minimum of three
years. If monitoring data shows an increase in contaminant
levels over time, such that the asymptotic condition is
significantly changed, active pumping will be resumed.
Passive Collection System Cleanup Levels (Influent
Concentrations)
The management of migration objective of the passive
collection system is to prevent degradation of the unnamed
stream by collecting seeps and contaminated groundwater.
Cleanup levels for the passive system will be based on
Ambient Water Quality standards (AWQS) and the designated
uses of the receiving waters. EPA has selected AWQSs as
cleanup levels b~cause they are appropriate standards for
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49
the protection of aquatic life in the unnamed stream. EPA
anticipates that either ambient water quality criteria for
specific pollutants or bioassays will be used to determine
c=rp!ian=e ~ith Massachusetts water quality standards.
co~p1ia~ce with these cleanup levels will be measured at the
influent to the treatment plant. Collected leachate and
ground~ater will be monitored before and after entering the
groundwater treatment plant.
c.
Effluent Concentration for Treatment Plant
Massachusetts ambient water quality standards (AWQSs) will
also be used to set effluent limitations so that the
discharge to the unnamed stream will not result in
violations of the state's water quality standards. These
standards include minimum criteria as well as narrative
standards including "surface waters shall be free of toxic
pollutants in toxic amounts." EPA anticipates that either
aIT~ient water quality criteria for specific' pollutants or
whole effluent toxicity limits will be specified as effluent
limitations for the treatment plant's effluent. Based on
the specific limits set for the effluent, appropriate
monitoring requirements will also be specified, including
bioassays. Specific effluent limits which comply with water
quality standards and monitoring requirements will be
determined during remedial design and will be based in part
on the evaluation of predesign and pilot results. If at
some point in the future it is determined to be more cost-
effective to discharge to the New Bedford POTW, then the
effluent limitations, as discussed above, will be amended to
reflect pretreatment requirements.
c.
Rationale for selection
The choice of the selected alternative is based on the criteria
listed in the evaluation of alternatives section of this
document. In accordance with section 121 of CERCLA, to be
considered as a candidate for selection in the ROD, the
alternative must be protective of human health and the
environment and able to attain ARARs unless a waiver is granted.
At the Sullivan's Ledge site, attainment of groundwater ARARs is
technically impracticable from an engineering perspective, and a
waiver from compliance with those ARARs is justified. In
assessing the alternatives at this site, EPA focused on other
evaluation criteria, including short term effectiveness, long
term effectiveness, implementability, use of treatment to
permanently reduce the mobility, toxicity, and volume of
contaminants, and cost. EPA also considered nontechnical factors
that affect the implementability of a remedy, such as state and
community acceptance. Based upon this assessment, taking into
account the statutory preferences of CERCLA, EPA selected the
remedial approach for this site.
-----------.--------...-. ...
.' - -- - ..
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50
Alternative SA-5 represents the best combination of elements
~d~ressing contaminated soils, sediments and groundwater. The
selected alt~rnative is protective, effective in the long term
and the short term, reduces the toxicity, mobility and volume of
the conta~inants, is implementable, has state and community
acceptance and is cost-effective.
Most of the on-site soils are contaminated with PCBs, with
approxi~ately 24,000 cubic yards in excess of 50 ppm of PCBs.
The cle2n-up level for sediments within the adjacent unnamed
stream is less than 1 ppm. Therefore, for this site it is
critical to ensure that on-site soils will not erode off-site
into the unnamed stream. EFA has determined that solidification
of the more highly contaminated soils and disposal under a cap is
necessary to ensure that in the long term contaminated soils will
not ~obilize and erode off-site into the unnamed stream and is
consistc~t with the preference for treatment as a principal
ele~ent. Solidification also provides an added measure of
security against possible future costs and remedial action
necessary to protect human health and the environment if the cap'
were to fail. Excavation of contaminated sediments within the
unnamed stream and water hazards is necessary to reduce the
unacceptabl~ environmental risk posed by such contaminated
sediments for aquatic organisms and organisms at higher trophic
levels. Solidification and on-site disposal for excavated
sediments is the most cost-effective alternative considering the
long term effectiveness and the significant reduction of mobility
similar to other sediment treatment alternatives but at less
cost, and the need to convert dewatered sediments into a suitable
filler for" disposal under a cap. As previously discussed, EPA
has determined that it is technically impracticable, from an
engineering perspective, to clean the contaminated groundwater to
cor-ply with drinking water standards. However, EPA has further
determined that an active pumping collection system, located in
close proximity to the pits, is required to significantly reduce
the level of groundwater contaminants located in the on-site
bedrock aquifer. In addition, because of unacceptable
environmental risks due to contaminated groundwater and seeps
discharging into the unnamed stream, a passive groundwater
collection system is necessary for the short and long term during
downtimes and upon successful completion of the active pumping
system.
other alternatives were considered less acceptable for the
following reasons. Because Alternative SA-l, the no-action
alternative, did not address risks from exposure pathways, it is
not protective and was rejected from further consideration. All
other alternatives included an element to reduce risks from
exposure to contaminated soils. However, capping alone
(Alternatives SA-2, SA-3) was not selected because it does not
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51
wastes, does not provide protection if the cap should fail and
the long term effectiveness is less certain. Alternatives
involving in-situ vitrification and incineration for soils
(Altern?tivp.~ SA-6 and SA-a) were rejected, even though the
treatments would permanently destroy PCBs, because of
implementability problems and substantially greater cost than
solidification. Solidification was selected because it will
reduce thG mobility of PCBs and PARs and will provide an extra
measure of protection and long term effectiveness when used with
a cap. Alternatives which did not address contaminated sediments
(Alternatives SA-2, SA-3) were rejected because they do not
reduce risks to aquatic and terrestrial organisms from exposure
to contaminated sediments. Alternatives which did not utilize an
active collection and treatment system to address groundwater
conta~ination (Alternatives SA-2, SA-4, SA-6) were rejected
because they are ineffective in the long term, do not
significantly reduce the toxicity, mobility and volume of
conta~inants in the groundwater, and are not acceptable to the
state. Alternatives which utilized an active collection and
treatment system, but did not include a passive collection and
treatment system (Alternatives SA-3, SA-7, SA-a), were rejected
because they are not protective of the environment in the long
term. Because it is technically impracticable to extract all
pockets of contaminants located in the quarry pits and bedrock
fractures, and an indeterminate amount of contaminants will
therefore remain in the groundwater after the active collection
and treatment. system has been turned off, the passive collection
system will be necessary to reduce environmental risks from
exposure to groundwater seeps and/or further contamination of the
unnamed stream and sediments.
XI.
statutory Determinations
A.
The Selected Remedy is Protective of Human Health and
the Environment
The remedy at this site will permanently reduce the risks posed
to human health and the environment by exposure to contaminated
soils, sediments, surface water and groundwater.
The soil cleanup levels to be attained by this reThedy will reduce
the risks from direct contact to and incidental ingestion of
contaminated soils to a level protective of human health. In
addition to solidification, construction of an impermeable cap
r" .., .,... -
. -" -.-.
......- --.---- ---.. .--..-----.-.
-..--- . ---.-
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52
.
over most of the surface area of the site will provide an
additional barrier against ex~osure to conta~inated soils by both
human and enviL"onI:!ental receptors. The combination of
solidification and capping will also significantly reduce the
potential for contaminated soils to migrate off-site via the
unnar.ed stream. Periodic site visits and maintenance will be
performed to ensure the integrity of the cap, and its
effectiveness in preventing exposure to contaminated soils and
wastes within the pits. Similarly, institutional controls will
be iwplemented to regulate land use of the site, including
activities which may compromise the integrity of the cap.
Treatment of the PCB-contaminated sediments in the unnamed stream
and golf course water hazards will permanently and significantly
reduce the risks to benthic organisms and organisms at higher
trophic levels associated with contact with such sediments and
subsequent bioaccumulation.
Risks fro':'. exposure to contaminated on-site overburden and
bedrock groundwQter and groundwater seeps will be permanently
reduced. EPA has dete~ined that it is technically impracticable
to clean up the contaminated groundwater to drinking water .\
standards, both on-site and immediately off the disposal site.
However, attainment of groundwater cleanup goals, as measured by
achievement of 1-10 ppm of total volatiles and/or an asymptotic
curve using groundwater monitoring data, will result in a
significant reduction of on-site groundwater contaminants.
Groundwater within the zone,of contamination is not currently
used for drinking vater sources. Institutional controls will be
irple~ented.to ensure that in the future, drinking water wells
will ~ct be drilled on- and off-site within the zone of
groundwater contamination.
B.
The Selected Remedy Attains ARARs
The remedy ~ill meet or attain applicable or relevant and
appropriate federal and state requirements that apply to the
site, with the exception of requirements relating to groundwater,
as discussed below. Federal environmental laws and regulations
which are applicable or relevant and appropriate to the selected
remedial action at the Sullivan's Ledge Site are:
Resource Conservation and Recovery Act (RCRA)
Toxic Substances Control Act (TSCA)
Clean Water Act (CWA)
Clean Air Act (CAA)
Occupational Safety and Health Administration
Safe Drinking Water Act (SDWA)
Department of Transportation Regulations
(OSHA)
State environmental regulations which are applicable or relevant
and appropriate to the selected remedial action at the site are:
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53
Dept. of Environmental Quality Engineering (DEQE) Regulations
Hazardous Waste Regulations
~etlands Protection Regulations
Cp.r.tification for Dredging and Filling in Waters
Drinking Water Regulations
Air Quality standards
Air Pollution Control Regulations
y.assachusetts Division of Water Pollution Control (MDWPC)
Regulations
Surface Water Quality standards
Groundwater Quality standards
Supp. Requirements for Hazardous Waste Management Facilities
Table 3 provides a synopsis of the applicable or appropriate
requirements for the selected remedy. A discussion of how the
selected r~medy meets those requirements follows.
"0 .-- --_..~- ~-- ..... - ....-.
- . ...~. ...._--_.,..~. ..
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54
g;--9.1d.nd~g~~!"
Safe Drinkinq Water Act
~::...c::~_~~b"~~~':"_t-ts DEOE Drinkinq Water Recrulations
ba3sc~t~satts ~DWPC Groundwater Ouality Standards
The groundwater at Sullivan's Ledge, both on-site and immediately
off-~itc, is not currently used as a drinking water source, but
is a potential drinking water source. Maximum Contaminant Levels
(MCLs) promulgated under the Safe Drinking Water Act and
Massachusetts Drinking Water Standards, which regulate public
drinking water supplies, are not applicable. However, because
the gro~ndwater could potentially be used as drinking water
source, MCLs are relevant and appropriate. Minimum Groundwater
Criteria established under the Massachusetts Groundwater Quality
Standards are relevant and appropriate.
In this Record of Decision, EPA is waiving compliance with
cert~in ARARs relating to groundwater. The waiver covers both
federal and state ARkRs. Specifically, the Maximum Contaminant
Levels (XCLs) prorn~lgated under the Safe Drinking Water Act,
Massachusetts Drinking Water Standards and Massachusetts
Groundwater Quality Standards are waived. EPA has determined
that compliance with the requirements of these ARARs is
technically impracticable from an engineering perspective.
Accordingly, EPA is waiving these requirements pursuant to
Section 121(d) (4) (C) of CERCLA, 42 D.S.C. ~ 9622(d) (4) (C).
The determination of technical impracticability is based
primarily on the nature of the wastes and contaminants within the
pi ts and along the bedrock fractures, "and the geology of the
site. EPA has concluded that the quarry pits and bedrock
fractures contain dense non-aqueous phase liquids (DNAPLs), as a
result of direct dumping of liquid wastes into the pits at depths
approaching 150 feet into bedrock. The bedrock fractures are
irregular both in length and orientation and as such cannot be
accurately located, especially at such depths. In addition,
DNAPLs will distribute along bedrock fractures under the
influence of gravity, not just in the direction of flow,
resulting in the inability to predict their locations even along
a specific fracture. Therefore, the pockets of highly
contaminated wastes located within the pits and along fractures
cannot be cleaned up by conventional excavation and pumping
methods as it is technically not possible to locate and extract
all the contaminated pockets. The excavation of the ~Jarry pits
would also require an operation which is logistically infeasible
to implement considering decontamination, staging and disposal
constraints for the liquid wastes and solid objects within the
pits. Even if the remedy did include excavation of the quarry
pits, some contaminants would certainly remain in the pits and
along the bedrock fractures.
- . . ~-...- -.. - .----- ------
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55
Groundwater will be treated to the target levels discussed in
Section X.B.3. The groundwater treatment facility will be
located outside of the 100-year floodplain on the golf course,
i=~cdi~te~y udjacent to the disposal site. The location of the
facility attains the siting requirements of MDWPC Supplemental
Requirements for Hazardous Waste Management Facilities. There
are no suitable areas on site for constructing the treatment
facility, because quarry pits underlie much of the site and
because construction of the facility may harm the cap. The
proposed location is within the areal extent of contamination,
and is considered to be part of the site for the purposes of
Section 121(e) of CERCLA. Therefore, no permit is required.
Discharges from the treatment facility into the unnamed stream or
to th~ l';E",i Bedford sewer will attain ARARs, as described below.
Soils and Sediments
The applicable or relevant and appropriate requirements for the
excavation, solidification and capping of the contaminated soils
and sedi~ents are regulations promulgated pursuant to TSCA, RCRA
and DEQE Hazardous Waste Management Regulations.
Toxic .substance~ control Act
The PCB Disposal Requirements promulgated under TSCA are
appl icable to the site because the s"elected remedy involves
.disposal of soils and sediments contaminated with PCBs in excess
of 50 pprn. Under the Disposal Requirements, soils contaminated
with PCBs ~ay be disposed of in an incinerator, chemical waste
landfill, or may be disposed of by an alternate method which is a
destruction technology and achieves an equivalent level of
performance to incin~ration. 40 C.F.R. SS 761.60(a) (4),
761.60le). In this case, placement of solidified soils and
sediments on the top of the ground surface of the existing
landfill and construction of an impermeable cap over 11 acres of
the site will satisfy the requirements of a chemical waste
landfill. The passive groundwater collection system will collect
leachate and monitoring of groundwater wells will be instituted,
as required by the chemical waste landfill regulations.
The Regional Administrator is exercising the waiver autho~ity
contained within the TSCA regulations at 40 C.F.R. S
761.75(c) (4), and is waiving certain requirements of the chemical
waste landfill. The provisions to be waived require construction
of chemical waste landfills in certain low permeable clay
conditions [40 C.F.R. ~ 761.75(b) (1)], the use of a synthetic
membrane liner (S 761.75(b) (2)], and that the bottom of the
landfill be 50 feet above the historic biqh water table (S
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56
The Regi'cnal Adlliinistrator hereby determines that, for the
following reasons, the requirements of 40 C.F.R. SS .
'761.75(0) (1), (~) and (3) are not necessary to protect against an
un~e~son~~le risk of injury to health or the environ~ent from
PCBs in this case.
Low permeability clay conditions for the underlying substrate are
not necessary at this site to prevent migration of PCBs. Soils
and sediments over 50 ppm will be solidified and placed on top of
the existing ground surface and clean fill. Solidification of
soils with PCBs over 50 ppm and an impermeable cap will
effectively encapsulate PCBs and prevent future migration. The
require~ent of a synthetic membrane liner is waived because there
will be no hydraulic connection between the solidified mass and
the groundwater or surface water. Although the water table at
Sullivan's Ledge is five to ten feet below the ground surface,
infiltration of PCBs to the groundwater will be prevented by
binding the PCBs in a solidified mass and placing them under an
impermeable cap. Also, installation of the active collection
system and the cap may further lower the groundwater level.
Surface erosion of PCBs in soils and transport of the soils into
the unnamed stream will essentially be prevented by the
co~~ination of solidification and placement under an impermeable
cap. The hydrologic requirement that the landfill must be fifty
feet above the historic high water table is waived because it is
extremely unlikely that the solidified soils and sediments will
ever come in contact with the groundwater. The solidified
materials will be placed on the ground surface, five to ten feet
above the water "table, and will not be located in a floodplain,
shoreland or groundwater recharge area. These factors ensure
that at this site there will not an unreasonable risk of injury
to health and the environment if the above requirements are
waived.
Hazardous and Solid Waste Amendments to the Resource
Conservation and Recovery Act
The Commonwealth of Massachusetts has been authorized by EPA to
administer and enforce RCRA programs in lieu of the federal
authority. Compliance with Massachusetts RCRA regulations is
discussed below. However, federal regulations promulgated under
the Hazardous and Solid Waste Amendments to RCRA (HSWA) are
potentially applicable.
... ..- . --..-.-...--....-
-- . --"-----.-.---. -----
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57
The appiicability 0: HSWA regulations depends on whether the
~astes are hazardous, as defined under RCRA.4 In this case,
c~r~ai~ cc~pounds which may exhibit characteristics of hazardous
waste, ~'JC~ AS hariurn and lead, are present in some limited areas
of the soils. However, HSWA regulations will not be applicable
to thC3~ soils, be~ause the Agency expects that after the soils
are solidified, they will no longer exhibit any characteristics
of hazardous wastes. Accordingly, HWSA land disposal
restrictions will not be applicable because placement of the
solidified soils on the land will not constitute disposal of a
hazardous ~aste. 5
The minimum technology standards for landfills promulgated
pursuant to HSWA are not applicable, because the Sullivan's Ledge
site is an existing landfill, rather than a new landfill, a
lateral expansion, or a replacement landfill. Furthermore, the
double liners required under these standards are not relevant and
appropriate to this site. Because contaminants exist deep within
the quarry pits and in the bedrock fractures, it is technically
infeasible to build double liners that would prevent contaminants
from coming into contact with groundwater. Accordingly, bottom
double liners would not serve the purpose of isolating
contaminants from the groundwater. Leachate collection
. requirements are relevant and appropriate, with the exception of
the length of operation requirement. The passive groundwater
collection system will collect leachate until Massachusetts water
quality standards are achieved.
~The agency has determined that none of the wastes in the
soils and sediments at Sullivan's Ledge are listed hazardous
~astes under RCRA because the specific processes creating the
wastes are unknown. The mere presence of a hazardous constituent
in a waste is not sufficent to consider the waste a RCRA listed
waste.
5 HSWA land disposal restrictions (LDR) would be applicable
to the disposal of those portions of the soils contaminated with
RCRA hazardous waste if they also contain certain restricted
wastes. Under LDR, if soils contaminated with a RCRA hazardous
waste (such as lead) also contain halogenated organic compounds
such as PCBs in excess of 1,000 ppm, they must be incinerated
prior to land disposal. At Sullivan's Ledge, it appears that the
soils with high lead content do not also contain PCBs greater
than 1000 ppm. Even if that were the case, incineration would
not be appropriate because of the high lead content, and EPA
would invoke a variance from the treatment standard pursuant to
40 CFR ~ 268.44, allowing treatment of the lead- and PCB-
contaminated soils by solidification.
--.
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58
y.assachusetts DEOr Hazardous Waste Requlations
M~~=achusetts' DEQE Hazardous Waste Regulations are r~l~v~~t and
~r~rorriate to this site, because the wastes to be managed are
either hazardous wastes or are similar to hazardous wastes.'
~he placement of contaminated soils and sediments under a cap
~ill occur outside the lOO-year floodplain, in accordance with
location standards in the Massachusetts Hazardous Waste
Regulations. Massachusetts closure and post-closure requirements
requiring, among other things, that a cap attain a certain low
permeability standard and act to minimize migration of liquids
through the landfill in the long term will be attained. In
addition, the substantive elements of the contingency plan,
emergency procedures, preparedness and safety requirements will
be satisfied.
The portio~ of th€ DEQE landfill regulations requiring a double
liner is not appropriate to the site and will not be attained.
Large volu~es of wastes will be left in the quarry pits
underlying the solidified material, because of the
i~practicability of excavation, as described above. Thus,
place~ent of a double liner over the wastes in the quarry pits
would be ineffective in containing the wastes. Leachate
collection requirements are relevant and appropriate, with the
exception of length of operation requirements. The passive
system will collect leachate and will operate until water quality
standards are achieved.
The groundwater monitoring program will comply with the
groundwater protection regulations under the DEQE regulations,
with the possible exception of s~mi-annua1 monitoring. As
currently conceived, the remedy calls for groundwater monitoring
quarterly during the first three years, and the frequency
thereafter will be finalized during remedial design. Semi-annual
monitoring requirements may not be appropriate to this site,
, Massachusetts Hazardous Waste Regulations are not
applicable, because the remedial action implementing this Record
of Decision will be initiated or ordered by DEQE as well as EPA.
In such circumstances, no license pursuant to the Massachusetts
hazardous waste statute and DEQE hazardous waste regulations is
required. 310 C.M.R. 30.801(11). Accordingly, DEQE does not
require strict compliance with all hazardous waste regulations
for such remedial actions, but only requires compliance with the
relevant and appropriate substantive sections of those
regulations.
~- --.
.~_. . - .
--- -. . ..---
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59
*here the primary purpose of groundwater monitoring is not to
check th~ effectiveness of the cap, but to assess the
effectiveness of the groundwater extraction and treatment
program.
Surface Water
Clean Water Act
Some regulations under the Clean Water Act are applicable to the
discharge of treated waters to the surface waters of the unnamed
stream. No permit is req-J!.red. under the NPDES program for this
discharge, becau~e the effluent from the treatment facility will
be discharged directly into the unnamed stream at a point
considered part of the CERCLA site. EPA has selected a treatment
method combining chemical oxidation/filtration for metals removal
and UV/ozonation for organics removal which will be capable of
achieving state water quality standards. Pilot testing of the
treatment system will be conducted as part of the remedial
action.
- .
If the City cf ~ew Bedford builds a secondary treatment plant
(POTW) at some point in the future, EPA may discharge groundwater
collected by the passive system indirectly to the POTW through
the sewer. In that case, EPA would comply with pretreatment
requirements of the Clean Water Act. These regulations contain
general prohibitions against interfering with the operation of a
POTW and against pass-through of pollutants, and specific
prohibitions against introducing pollutants that will create a
fire or explosion hazard, or cause corrosive structural damage to
the POTW, areonq other things.
Massachusetts Surface Water Quality Standards
u
Massachusetts water quality standards for discharge to surface
*aters are applicable to discharges to the unnamed stream. The
unnamed stream is classified as Class B, for the uses and
protection of propagation of fish, aquatic life and wildlife, and
for primary and secondary contact recreation. Massachusetts
standards state that water shall be free from pollutants that
exceed the recommended 'limits, that are in concentrations
injurious or toxic to humans, or that exceed site-specific safe
exposure levels determined by bioassay using sensitive species.
At Sullivan's Ledge, these standards will be attained by using
either ambient water quality standards or whole effluent toxicity
limits. Bioassay tests may also be performed to determine site-
specific safe exposure levels. Because the effluent from the
treatment facility will be discharged directly into the unnamed
stream at a point considered part of the site, no permit is
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60
FloooDlains and Wetlands ARARs
R€g~l~~icns under section 404 of the Clean Water Act are
applic~bl~, ~cCdUS= channelization and lining of the unnamed
stream and construction of roads in the wetlands will involve a
discharge of dredged or fill material. The Agency has determined
that in this case there is no other practicable alternative which
would address PCB contamination in sediments but which would alsc
have a less adverse impact on the aquatic ecosystem. The
selected ren,e~y will comply with the substantive requirements of
section 404 to ~iinimize adverse impacts to the aquatic ecosystem,
by creating sedimentation basins, by erecting baffles in the
lined part of the stream, and by restoring the stream and
wetlands.
In addition, the policies expressed in Executive Orders regarding
wetlands and floodplains were taken into account in the selected
remsdy. The remedy will include steps to minimize the
destruc~ion, loss, or degradation of wetlands in accordance with
Execut~ve Order 11990, and will include steps to reduce the risk-,
of floodplain loss in accordance with Executive Order 11988.
DEQE Wetlands Protection Regulations concerning dredging,
filling, altering or polluting inland wetlands are applicable to
the dredging of the unnamed stream and water hazards. The
remedial action will comply with the performance standards o£ the
regulations regarding banks, vegetated wetlands, and lands under
water, and a one-for-one replication of any hydraulic capacity
which is lost as the result of this part of the remedial action.
Because the stream and water hazards are within the areal extent
of contamination, they are considered part of the site, and no
permits will be necessary.
Air
Standards for particulate matter under the Clean Air Act and DEQE
Air Quality and Air Pollution regulations are applicable and will
be attained during construction phases.
OSHA/Riqht to Know
OSHA standards for general indu~tries and health and safety
standards will be attained. Informational requirements under the
Massachusetts right to know regulations will be attained during
implementation of the remedy.
Department of Transportation Regulations
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61
;~y hazardous wastes transported for off-site disposal, including
any solids extracted during the groundwater treatment program,
will be transported in accordance with Department of
T~~~~~=rta~icr. regulations.
C.
The Selected Remedial Action is Cost Effective
Of those remedial alternatives that are protective and attain all
technically practicable ARARs, EPA's selected remedy is cost-
effective. As discussed in the FS, solidification is the most
cost effective treatment alternative for soils and sediments,
based on the treatment of equivalent volumes. In particular, the
cost of on-site incineration is $13,500,000 (present worth) for
treatment of soils with PCBs in concentrations equal to or
greater than 50 ppm. This is $9,000,000 more than the cost of
solidification for treatment of the same volume of soils.
Although solidification is not a destruction technology,
solidification and capping, in combination with a long-term
maintenance program and institutional controls, will adequately
protect human health and the environment over the short- and
long-term. Because the site must be capped in ~ny event to
contain the wastes within the quarry pits, solidification of
soils and sediments represents the most cost-effective treatment
means of achieving the response objectives outlined in section
VIII A. .
D
Present worth costs were estimated in the FS for four groundwater
treatment technologies for the active collection system: air
stripping with granular activated carbon (GAC), air stripping
with GAC and vapor phase carbon, GAC alone and UV/ozonation. Of
the four referenced treatment systems, UV/ozonation has the
lowest cost estimate in present worth terms. Although GAC is a
commonly used treatment for removal of VOCs, vinyl chloride, one
of the contaminants of concern in the groundwater at the site,
quickly exhausts the adsorptive capacity of GAC. UV/ozonation is
a technology which has been proven to be effective in the
destruction of organic contaminants in groundwater, including
vinyl chloride. Therefore, the selection of UV/ozonation as a
groundwater treatment system is the most cost-effective both in
terms of its destruction efficiency and estimated cost.
Implementation of the active groundwater collection system will
be required until the time that the levels which the Agency
considers technically practicable, as described in section
X.B.3.a., are achieved. The combination of an active and passive
groundwater collection system is cost-effective because it
reduces the length of time of the operation of the active
collection system. If no passive system were in place, it would.
be necessary to operate the active system until water quality
standards were achieved in order to prevent degradation of the
unnamed stream. Construction of the passive system represents a
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62
D.
The Selected Remedy utilizes Permanent Solutions and
Alternative Treatment Technologies or Resource Recovery
'I'cotnologies to the Maxicum Extent Practlc~le
EPA has determined that the solidification, capping, and
groundwater treatment components of the selected remedy utilize
permanent solutions to the maxim~ extent practicable.
In this case, it is technically impracticable from an engineering
perspective to excavate all the wastes contained within the
quarry pits and deep bedrock fractures, and therefore technically
impracticable to eliminate permanently the source of groundwater
contamination. All the source alternatives which EPA evaluated
for cOwplete and permanent remediation of wastes contained within
the quarry pits were screened out in Chapter 9 of the FS, because
of problems with their effectiveness, implementability and cost.
The determination that it is technically impracticable to
excavate wastes in the quarry pits and bedrock fractures is based
primarily on the nature of the wastes present and the geology of -
the site. The evidence indicates that the quarry pits and the
bedrock fractures contain pockets of highly contaminated liquids.
These pockets cannot be cleaned up by conventional excavation and
pu~ping methods, as it is technically not possible to locate and
extract all contaminated liquids. The excavation of the quarry
pits would also require an operation which is logistically
impracticable to implement, considering decontamination, staging
and disposal of wastes and objects in the pits. Significant short
term hazards may result from excavating large bulky objects such
as cars and timbers which are significantly contaminated by the
liquid wastes.
The remedy also uses alternate technologies. Solidification of
soil and sediment is designated as an innovative treatment, as is
UV/ozonation.
E.
The Selected Remedy Satisfies the Preference for
Treatment as a principal Element
The selected remedy satisfies the statutory preference for
treatment as a principal element by specifying excavation and
solidification of contaminated soils and sediments equal to or
above human health-based and environmental risk-based target
levels. Solidification of contaminated soils and sediments is a
form of treatment which significantly reduces the mobility of
PCBs. Although not as permanent as destruction technologies,
solidification provides more long term protection than capping
alone.
-- --- - -----. -..-..-.. -.. ------...-----.-- _._--.. _... ------- - ---....-- - ..
-------
63
The qroundwater treatment system also utilizes treat~ent. As
described in preceding sections, EPA has determined that it is
tc~hnic~lly i~Fracticable, from an engineering perspective, to
exc~vate a~d treat all the solid and liquid wastes within the
quarry pits. However, since the liquid wastes within the pits
constitute the primary threat to human health and the
envircn~e~t, the remedy specifies a groundwater extraction and
trcat~cnt system located in close proximity to the pits in order
to significantly reduce the mass of contaminants in groundwater.
The groundwater treatment system of chemical precipitation
follo~ed by UV/ozonation will permanently destroy organic
contaminants and remove metal contaminants from collected
groundwater.
XII.
STATE ROLE
The Massachusetts Department of Environmental Quality Engineering
(MA DEQE) has reviewed the various alternatives and has indicated
its support for the selected remedy. The state has also reviewed
the Remedial Investigations and the Feasibility study to
determine if the selected remedy is in compliance with applicable
or relevant and appropriate state environmental laws and
regulations. ¥~ DEQE concurs with the selected remedy for the
sullivan's Ledge Site~ A copy of the declaration of concurrence
is attached as Appendix c. .
Because the city of New Bedford, a political subdivision of the
Commonwealth of Massachusetts, operated the site at the time of
disposal of hazardous substances, the state is responsible for a
minimum of 50 percent of the sums expended in response to
releases at the site, in accordance with section l04(C) (3) of
CERCLA. In the case of the selected remedy, the Commonwealth's
minimum share is estimated at approximately $5,050,000.
.... ---.. ~-_.._-_.--_._.- ..---.'
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USE MAP SOURCE' USGS OUAORANGL.E. 7., MINUTE SERIES
.' HEW 8EO'OAC NOATH. MA.
SCALE. ,8.2013'
AGURF ~
SITE LOCATION AP
SULlJVAN'S'LE~ srre
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FLOOD STAGE MAP (100 - YEAR FLOOD)
SULLIVAN'S LEDGE SITE. NEW BEDFORD. MA
SCALE ," = '00 I
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::::=: fOC1f ...... = = = ~O_O
" GRf EM un,," f'OS ( VOC ) ( ~b
PHASE. SAMPLING OF EXISTING OVERfJU110[N WELl!
SULLIVAN'S LEDGE !~11I
NEW 8EDFORD, MASSACHUSET1!
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FIGURE
SITE PREPARATtON PLA,
SULLIVAN'S LEDGE LANDFILl
-------
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LECEIIO
. .8~
. C~,""'- POWf
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F [CURE ()
SEDIMENT REMOVAL ARF.AS
SULLIVAN'S LEDGE I.ANDFILL
-------
FR:)3T P'CN-:TRJ..TION
R=,-vT 6~:=oR:>.-";A.
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7 6
2% MlNIMUM SLOPE
-,
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24" RECOMPACTED CLAY k = 1 X 10.7 em/see
1.;.(-8
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~:~::::::::::::::::::::::::::
r~~rr~rr\r/{rtrrrtt:@r~::::::::-'" EXISTING SURFACE
",
FiGURE 7
PROPOSED CAP OES)GN
SULLIVAN'S lEDC~ SITE
-------
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LEGEND
~---. FINAL GRADING CONTOUR
. - .-
-----
I
J AREAL f.XTENT Of' CAP
.
:I:::---:r: ~-- Tr.A CHANNEl AND
~ -=:L 5Uf. SlOf'ES
A A'
~---J CROSS Sf.CTIOH
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~~ A~A~.~
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FIGURE 8
PROPOSED SITE CAP
SULLIVAN'S LEOGt: 51 , t:
OttO MASSACHUSETTS
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72
TABLE
1
INDICA. TOR COMF>OUNDS
SULUVAN'S LEDGE SITE
NEW BEDFORD, MASSACHUSETTS
2-buU~one
4-m ~thyl.2 'pental'lone
be~zene
toluene
xylenes .
ethyl be nzene
chi orobenzene
1,2-dichloroe1hane
Penuehlorophenol
bis(2~th il hexyl) phthalate
polycyclic arorT'tatic hydrocarbons (PAHs)
acenapthane
acer'\~pthylene
anthracene
be~zo(a)anthracene
benzo(b)fluoranthene
benzo(k)fJuoranthene
be rtzo(g ,h,i)perylene
ber".zo(a)pyrene
chrysene
di be nzo(a,h)anthracene
fluoranthene
fluorene
ideno( 1 ,2,3-td)pyren.
ph ena nthr.ne
pyrene
naphthalene
2.methylnapnthalene
2-chl orona pnthalene
VOLATILE ORGANICS
SEMI-VOLATilE ORGANICS
Acid Extractables
Base/Neutral EXtractables
trans-1,2-dichloroethene
trichloroe1hene
vinyl chloride
chloroform
methylene chloride
Styrene
1,2-dichlorobenzene
1,3-dichlorobenzene
1,4-dichlorobenzene
1,2,4-trichlorobenzene
n-nitrosod i methyl ami ne
n.ni trosod i phenyl am i ne
bi s(2-<:hl oroethyl)ether
-------
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"13
Table 1 continued
INO:CA iOt: CO'M?OUNOS
SU~UVM\'S liOGE SiTe
PAGE TWO
PESTICIOeSIPCBs
PCB.1C16
ro. ~ 221
PCB.1232
PCB.1242
INORGANICS
barium
copper
iron
lead
manganese
mercury
nickel
PCB.1248
PCB.1254
PCB.1260
sil ver
sodium
-------
.
ALTERNATIVE
DEVELOPtfENT
(SECTION 9. 1)
SC-Soi Is-I
SC-Soi Is-2
SC-Soi ls-)
SC-Soi Is-I,
SC-Soi ls-S
SC-Soi ls-6
SC-Soils-7
SC-Soils-8
SC-Pits-I
SC-Pits-2
SC-Pits-)
SC-Pits-4
SC-Pits-S
SC-Pits-6
SC-Pi ls.-l
SC-Sed-)
SC-Sed-2
SC-Sed-)
SC-Sed-4
SC-Sed-S
SC-Sed-6
TABLE
2
SUtIHARY or SOIlRCE CONT~OI. ALTERNATIVES SCREENING
StJl.f.lVAN'S U:nGE SITE
NEW OmFOIW, HASSAClltJSETTS
AI.n:nNATIVE(S)
ELIMINATEn nUnlNG
COm'ATl 81 I.ITY
~!~TION 9.2)
AI.TElmATIVES AI.TERNATlVES
ELIHINATEU nURING R.:HA IN HIG f"OR
SCREENING or UETAI u:n
(SECTION 9.) EVAUJAT I ON
SC-I*
SC-Soi 18-2
SC~Soils-)
SC-Soi 1&-5
SC-Soi Is-6
SC-Soils-7
SC-Soi ls-8
......
SC-Pits-2 A
SC-Pits-J
SC-Pits-4
SC-Pits-S
SC-Pits-6
SC-Pits-7
SC-Sed-2
SC-Sed-J
SC-Sed-4
SC-Sed-S
SC-Sed-6
No Action
Containment
In-situ Vitrification
Off-sile HCRA Landfill
On-site Inctpcration
Off-site Inctneration
KPEG/Thermal Aer4tion
Solidification/on-site
Dhposa I
SC-Soi ls-I*
SC-Soih-4
SC-Pi ts-I*
SC-Sed-)*
*Note:
No Action
Containment
In-situ BiolQMical
Off-site RCRA Landfill
Solidificalion/Off-site
On-site Incineration
Off-site Incineration
Landfill
SC-Soils-l, SC-Pils-l, SC-Sed-J, Combined to SC-)
No Action
Containment
In-situ Bio)oR{cal
Excavation/On-site Disposal
Solidification/On-site Disposal
-------
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.
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TADLE
2 continued
SUMHARY OF HANAGEMENT OF HIGRATION AI.TERNATIVES SCREENING
SIII.LI VAN I S u:nGF. SITE
NEW Rt:OFOIW. HASSACIIUSETTS
ALTERNATIVF.
DEVF.LOPHENT
(SECTION 9. I)
A I.TEHNATIVF.
ELIMINATED DIINING
CmlPA" I It I L ITY
~ECTION 9.2)
AI.TERNATIVF.S
ELIHINATED DURING
SCHHNING 0..-
~ECTIQ~~}-
AI.TENNA1'IVF.S
Rt:MA I N I N(: FOR
I)I-:1'AIU:O
EVAWATIfIN
---- --
HH-I
No Action
HM-I
HH-2 Containment HH-2
HH-) Passive Collection HN-J
HH-4 Groundwater Diversion HH-4
HH-S Active Collection - Overburden HH-5
and Bedrock Groundwater
HH-6 Action Collection -Deep HH-6
Bedrock Fracture Groundwater
-I
-------
REQUIREMENT
76
Table
3 - ARARs
REQUIREMENT SYNOPSIS/CONSIDERATION
Safe Drinking Water Act
Regulations, 40 CFR
Part 141, Subpart B
TSCA PCB Disposal
Requirements, 40 CFR ~~
761.60
RCRA Land Disposal
Regulations, 40 CFR ~
268 Subpart C
RCRA Minimum Technology
Regulations, 40 CFR ~
264.300
Establishes MCLs for public
drinking water supplies. These relevant
and appropriate regulations will be
waived because of technical
impracticability.
Disposal of soils and sediments
with PCBs over 50 ppm, must be by
incinerator or equivalent alternative
method, or chemical waste landfill.
Remedy will result in chemical waste
landfill containing existing wastes
which have been previously landfilled on
site and solidified soils and sediments.
Some requirements of chemical waste
landfill which are not necessary to
protect against risk of injury to health'
or environment will be waived under the
waiver provisions of the TSCA .
regulations.
These regulations are not applicable
because solidified soils are not
expected to 'contain characteristic
or listed hazardous waste.
These regulations establish standards
for new or replacement landfills, or
lateral expansions of landfills,
including double liner and leachate
collection. Not applicable because
remedy does not involve creation of new
or replacement landfill, or lateral
expansion of landfill. Double liners
are not relevant and appropriate because
it is technically infeasible to
construct a double liner separating
wastes in quarry pits from the
groundwater. Remedy will comply with
leachate collection requirements, except
inappropriate length of operation
requirements. .
-------
Surface Water Discharge
Reg~laticns, 40 CFR ~~
122, pro~ulg~ted.
pursuant to Clean
\oiater Act
Pretreatment
Regulations for
Indirect Discharges
to POTWs, 40 CFR
Part 403
Discharge of Dredged
and Fill Materials
Regulations, 40 CFR 55
230, promulgated
under Section 404 of.
Clean Water Act
National Ambient Air
Quality Standards
(NAAQS), 40 CFR 5 50.6,
promulgated pursuant to
Clean Air Act
OSHA Worker Safety
Regulations, 29 CFR
Part 1910
Department of
Transportation
Regulations for
Transport of Hazardous
Materials, 49 CFR Parts
107, 171.1-172.558
.---"-' -- .-- .-.-
_. - '. -- --. .
77
Applicable to discharge of groundwater
treatment system effluent. If effluent
is discharged to surface waters,
regulations will be attained through
compliance with state water quality
standards, and monitoring of discharge.
These regulations control the discharge
of pollutants into POTWs, including
specific and general prohibitions.
If groundwater from passive collection
system is discharged to sewer after New
Bedford secondary treatment plant
becomes operational, these regulations
will be applicable, and the remedy will
comply through pretreatment.
This regulation applies to the use
of fill material in stream and wetlands.
Remedy will comply because there is no \
practicable alternative having a less
adverse impact on aquatic organisms, and
steps will be taken to minimize adverse
impacts, such as sedimentation basins,
baffles and stream and wetlands
restoration. .
These applicable regulations set primary
and secondary 24-hour concentrations for
emissions of particulate matter.
Fugitive dust from excavation,
treatment, solidification and disposal
will be maintained below these
standards, by dust suppressants if
necessary.
These applicable regulations contain
safety and health standards that will be
met during all remedial activities,
including construction of the cap and
installation of groundwater wells.
Requirements for transporting hazardous
materials off-site will be met.
_'__0-
-.-.--- .-...-"
-------
I'Iassachusetts
DEQE Drinking Water
~~.;~13'ti :':-.Z t : 1 C C~
22
Massachusetts MDWPC
Groundwater Standards,
314 CMR 6
Massachusetts
DEQE Hazardous Waste
Closure and Post
Closure Regulations,
3 1 0 C?'~ 9 9 3 0 . 58 0
and 30.590
Massachusetts
DEQE Hazardous Waste
Location Regulations,
310 CMR 30.700
Massachusetts
DEQE Hazardous Waste
Ground~ater Protection
Regulations, 310 CMR
30.660
Massachusetts
DEQE Hazardous Waste
Landfill Regulations,
310 CMR 30.620
Massachusetts
MDWPC supplemental
78
Establishes maximum contaminant levels
for public drinking water supplies.
Attainment of this relevant and
appropriate regulation will be waived
because of technical impracticability.
Establishes minimum groundwater
criteria. Attainment of this relevant
and appropriate regulation will be
waived because of technical
impracticability.
.The closure and post closure regulations
'are relevant and appropriate. The cap
will be constructed and maintained and
monitoring will be performed in
compliance with these requirements.
The 'cap will be constructed outside
the 100-year floodplain in accordance
with these relevant and appropriate
regulations.
The groundwater monitoring re~uirements
are. relevant and appropriate.
semi-annual monitoring for specified
indicators of hazardous constituents are
required to verify the effectiveness of
closure. The remedy will comply with
the substantive requirements, except
that monitoring will be quarterly for
the first three years and the frequency
will be reevaluated thereafter.
Landfill requirements include double
liners, leachate collection systems, and
technical requirements for cap.
Double liner requirements are not
appropriate to this site, since
groundwater below landfill will remain
contaminated. Other requirements are
relevant and appropriate and will be
attained, except that leachate
collection may be terminated prior to 30
years after closure, if target levels
for the passive system have been
achieved.
RCRA facilities subject to surface water
-------
Require~ents for
Hazardous Waste
Management Facilities,
3 :. .; Cl~ S
Massachusetts
MDKPC Surface Water
Quality Standards,
314 CMR 4
Massachusetts
DEQE Wetlands
Protection Regulations,
314 Cz.'oR 10
Massachusetts
DEQE Ambient Air
Quality Standards,
310 C~{R 6, and DEQE
Air Pollution, Control
Regulatio~s, 310 CMR 7
Massachusetts
Right to Know
Regulations
Standards to be Considered
Executive Orders
11990 and 11988
Interim Sediment
Quality Criteria
79
with DEQE re~~lations regarding
location, technical standards for
landfills, closure and post-closure, and
management standards.
Surface waters must be free from
pollutants which are present in toxic
amounts, which exceed recommended limits
for most sensitive use, or which exceed
safe exposure levels. These applicable
standards will be attained during
remedial design and operation of the
treatment system.
This applicable regulation sets
performance standards for dredging
banks, vegetated wetlands, and lands
under water. The remedy and mitigative
measures will attain these standards.
This applicable regulation sets primary
and secondary standards for emissions of
particulate matter. These standards
, will be met during implementation.
Informational requirements of these
regulations will be attained during
implementation.
These executive orders regarding
protection of floodplains and wetlands
were considered in the evaluation and
development of remedial alternatives.
The soil and sediment excavation and,
stream lining will be conducted in such
a manner to avoid or minimize adverse
impacts.
Interim sediment quality criteria were
considered in establishing target levels
for cleanup of sediments.
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