United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R01-88/029
September 1988
&EPA
Superfund
Record of Decision
Charles George Landfill, MA
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50277-101
REPORT DOCUMENTATION r.- REPORT NO. 2.
PAGE ' EPA/ROD/RO 1-83/0 29 ;
4. Title and Subtitlt
SUPERF'JND RECORD OF DECISION
Charles George Landfill, MA
^^Third and Fourtn Remedial Actions - Final
^•*uthor
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EPA/ROD/R01-88/029
Charles George Reclamation, MA I
Third and Fourth Remedial Actions - Final
16. ABSTRACT (continued)
fourth operable units and focuses on the control and cleanup of contaminants that have
spread or are spreading from the site, including the treatment of leachate collected as
part of the cap system. Investigations have identified contaminated ground water in
overburden, shallow bedrock, and deep bedrock zones. In addition, an estimated 500
yd^ of sediments require remediation, and vent emissions from the landfill are
contaminated with a wide array of VOCs. The primary contaminants of concern affecting
the ground water, sediments and air, are VOCs including benzene and TCE, organics
including PAHs, and metals including, arsenic.
The selected remedial action for this site includes: extraction and treatment of
shallow ground water plumes and leachate collected from the landfill cap system using
biological treatment, metals precipitation and carbon adsorption with onsite discharge
of the treated water into the aquifer or offsite discharge into nearby surface water;
collection and incineration of landfill vent gas emissions; excavation and
solidification of approximately 500 yd^ of contaminated Dunstable Brook sediments and
placement beneath the Phase II landfill cap; and ground water monitoring. The estimated
present worth cost for this remedial action is $11,320,000 which includes O&M costs of
$601,000.
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Record of Decision
Remedial Alternative Selection
Site Name and Location
Charles George Reclamation Landfill
Tyngsborough, Massachusetts
State of Purpose
This Decision Document represents the selected phase III remedial
actions for this site developed in accordance with the
Comprehensive Environmental Response, Compensation, and Liability
Act of 1980 (CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA), and to the extent practicable,
the National Contingency Plan (NCP); 40 CFR Part 300 fi£ sea.. 47
Federal Register 31180 (July 16, 1982), as amended.
The Commonwealth of Massachusetts has concurred with the selected
remedies of this document.
Statement of Basis
This decision is based on the administrative record for the site
which was developed in accordance with Section 113(k) of CERCLA
and which is available for public review at information
repositories located in the Littlefield Public Library,
Tyngsborough, Massachusetts, and at 90 Canal St., Boston,
Massachusetts. The attached index to the administrative record
identifies the documents upon which the selection of the phase III
remedial actions are based.
Description of the Selected Remedy
The selected remedies for the phase III cleanup at the Charles
George site represent the remaining cleanup measures anticipated
to be necessary. These phase III remedial actions consist of:
1. Extraction of contaminated southwestern and eastern shallow
groundwater plumes, and combined biological-based treatment
of the extracted groundwater with leachate collected from the
landfill cap system;
2. Deep bedrock groundwater and residential well monitoring;
3. Collection and incineration of landfill vent gas emissions;
and
4. Excavation and solidification of approximately 500 cubic
yards of contaminated Dunstable Brook sediments. The
solidified sediments will be placed on the existing Charles
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George landfill for capping as part of the phase II, source
control remedy for the sita>
The estimated present worth costs for these remedies,
including design, construction, and operating costs, and
assuming thirty years for remediation, are $8,800,000,
$1,301,000, $1,034,000 and $79,000, respectively. The total
estimated present worth cost for the phase III remedies is
$11,320,000.
Declaration
The selected phase III remedies are protective of human
health and the environment. These remedies satisfy the
statutory preference for treatment that permanently and
significantly reduces the volume, toxicity and mobility of
the hazardous substances, pollutants and contaminants as a
principal element. They also utilize permanent solutions and
alternative treatment technologies to the maximum extent
practicable, and are cost-effective. Except for the
attainment of Safe Drinking Water Act maximum concentration
limits (MCLs) in eastern deep bedrock groundwater at and near
the site, these remedies attain Federal and State
requirements that are applicable or relevant and appropriate
(ARARs).
Finding under Section 121fd)(41(C)
As discussed in more detail in the summary document to this
Record of Decision, the attainment of MCL ARARs in the
residual eastern deep bedrock plume has been found to be
technically impracticable. Primarily, this is because of the
difficulty in predicting groundwater flow in bedrock, and thus
the difficulty in defining the spatial extent of bedrock
contamination. Also, extraction pumping of the site's eastern
deep bedrock aquifer could increase contaminant migration by
drawing shallow groundwater contaminants into bedrock
groundwater. For further discussion, please see Chapters 6,
7, 11, and 12 of the Remedial Investigation (Ebasco, 1988),
Chapter 7 of the Feasibility Study (Ebasco, 1988), and
sections V.A and XI.A of the summary document to this Record
of Decision.
Date Michael R. Deland
Regional Administrator, EPA Region I
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CHARLES GEORGE RECLAMATION LANDFILL
SUMMARY OF PHASE III
RECORD OF DECISION
ENVIRONMENTAL PROTECTION AGENCY
REGION I
SEPTEMBER 29, 1988
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CHARLES GEORGE RECLAMATION LANDFILL
RECORD OF DECISION SUMMARY
TABLE OF CONTENTS
Contents Page
I. SITE LOCATION AND DESCRIPTION .......... 1
I. SITE HISTORY ................... 2
A. Response History ................ 2
B. Enforcement History .............. 4
III. COMMUNITY RELATIONS .............. 4
IV. SCOPE AND ROLE OF OPERABLE UNIT AND BRIEF
DESCRIPTION OF THE SELECTED REMEDY ....... 5
V. SITE CHARACTERISTICS .............. 6
A. Groundwater ................... 7
B. Leachate . . .* ................ 9
C. Residential Drinking Wells ........... 9
D. Air Quality ................. . .10
E. Sediment .................... 11
F. Surface Water .................. 12
VI.- SUMMARY OF SITE RISKS AND RESPONSE OBJECTIVES.- .12
VII. DOCUMENTATION OF SIGNIFICANT CHANGES ...... 14.
VIII. DEVELOPMENT AND SCREENING OF RESPONSE
ALTERNATIVES ...... ............ 15
A. Statutory Requirements/Response Objectives . . . 15
B. Technology and Alternative Development and
Screening .................... 16
IX. DESCRIPTION AND SUMMARY OF THE DETAILED ANALYSIS OF
ALTERNATIVES .................. 17
A. Leachate and groundwater alternatives ...... 17
B. Landfill Gas Alternatives ............ 20
C. Sediment Alternatives .............. 23
X. THE SELECTED REMEDY ............... 25
A. Groundwater and leachate remedy ......... 26
B. Vent emission remedy .............. 28
C. Sediment remedy ................. 29
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CHARLES GEORGE RECLAMATION LANDFILL
Record of Decision Summary
Contents
Table
XI. RATIONALE TOR STTT.ELTIUII AND POINTS OF
COMPLIANCE . .................. 30
A. Groundwater »"d leachate ............ 30
B. Vent Emissions ........ ......... 32
C. Sediment .................... 33
XII. STATUTORY DETERMINATIONS ....... ...... 33
A. The Selected Remedy is Protective of Human
Health and the Environment ........... 34
fi. The Selected Remedy Attains ARARs ........ 34
C. The Selected Remedial Action is Cost Effective,
and Uses Permanent Solutions and Alternative
Treatment Technologies to the Maximum Extent
Practicable. .................. 36
D. The Selected Remedy Satisfies
the Preference for Treatment as a Principal
Element ............... . ..... 37
LIST OF FIGURES
^FiT^frn»f Page Number
1. Site Location Map ................ 39
2. Estimated Spread of Groundwater
Contamination ............ ....... 40
LIST OF TABLES
Page
1. Maximum Chemical Concentrations in Groundwater .41
2. Maximum Chemical Concentrations in Leachate. . .43
3. Landfill Gas Emission Concentrations ...... 44
4. Maximum Chemical Concentrations in Residential
Ambient Air. . . ................ 45
5. Contaminant Levels for Sediments from Dunstable
Brook ...................... 46
6. CGL Contaminants of Concern - Phase III ..... 47
7. Summary of CGL Risk Assessment ..... ..... 48
8. Target Cleanup Levels .............. 50
9. Technologies considered in Phase III Feasibility
Study ...................... 51
10. Evaluation of Remedial Alternatives Based on Nine
Criteria .................... 53
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CHARLES GEORGE TIECLAMATION LANDFILL
Record of Decision Summary
LIST OF TABLES
Table Number Page Number
11. Groundwater Discharge Levels 64
12. Potential Chemical-Specific ARARs 65
13. Potential Location-Specific ARARs 68
14. Potential Action-Specific ARARs 70
15. Selected Remedy Costs 73
APPENDICES
Responsiveness SummaVy Appendix A
Announcement of Public Hearing Appendix B
State Concurrence Letter Appendix C
Administrative Record Index Appendix D
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CHARLES GEORGE RECLAMATION LANDFILL
SUMMARY OF PHASE III {
RECORD OF DECISION
I. SITE LOCATION AND DESCRIPTION
The Charles George Reclamation Landfill (CGL) is a seventy acre
mixed industrial, municipal and hazardous waste landfill located
approximately one mile southwest of the Town of Tyngsborough,
Massachusetts. See Figure 1. Land use in the vicinity of the
site is predominantly rural residential but also includes some
light industry and seasonal livestock grazing. Drinking water is
supplied by groundwater as well as a new water main installed as a
result of the Environmental Protection Agency's (EPA's) first
Record of Decision (ROD) for the site. The site is bordered to
the east by U.S. Route 3, Flint Pond Marsh and Flint Pond,
respectively. Dunstable Road and Dunstable Brook border to the
west, and the Cannongate Condominium complex is about 800 feet to
the southeast. Blodgett Street forms the northwest border,
eventually becoming Cummings Road further north of the landfill.
Figure 1 also shows the residential areas near the site and the
route of the new water main. In addition to the condominium's
ninety-six units, there are homes along Cannongate Road, Dunstable
Road, Red Gate Road and Blodgett/Cummings Road. Residences on Red
Gate Road, Dunstable Road north of Cannongate Road, and
Blodgett/Cummings Road are not served by the water main. Across
Flint Pond, a neighborhood is located on the Pond's northern
peninsula about one-half mile from the site. The Academy of Notre
Dame is on the eastern shore of Flint Pond, and the town center of
Tyngsborough is at the northeast corner of Flint Pond.
The landfill itself contains hazardous industrial waste disposed
primarily in the western area of the site from 1973 until at least
1976. Municipal waste was disposed onsite from the mid 1950's
until the landfill's closing, per order of the Massachusetts
Attorney General, in 1983. Presently the site has a thin soil
cover, and it contains two combined surface water and leachate
lagoons, two leachate collection systems, one operable
recirculating pump station, and twelve shallow gas vents. The
site's existing condition is described further in pages 2-2 through
2-6 of the Remedial Investigation (RI) (Ebasco/E.C. Jordan Co.,
1988) and pages 1-2 through 1-3 of the Feasibility Study (FS)
(Ebasco/E.C. Jordan Co., 1988).
Construction of a full synthetic landfill cap, pursuant to EPA's
second ROD for the site, should begin in early 1989. The cap
design includes a shallow perimeter leachate toe-drain, four
leachate storage tanks, a passive gas collection and venting
system, and a surface water diversion and sedimentation system.
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Surficial geologic deposits at the CGL consist of stratified sand
and gravel in the eastern area of the site, and silty glacial till
deposits to the west. Unconsolidated surficial deposits overlie
fractured biotite-gneiss bedrock in which quartzite sills have
intruded. In the eastern area of the site, landfill refuse rests
on bedrock, and to the west, more than 20 feet of silty till lie
between refuse and bedrock.
Three general zones of groundwater underlie the area: saturated
overburden, shallow weathered bedrock, and deep bedrock.
Overburden and shallow bedrock groundwater gradients indicate
water movement away from the landfill in all directions except
north. Two plumes of contaminated shallow groundwater have been
found to be currently moving to the east and southwest. Shallow
aquifers in these areas discharge to Flint Pond Marsh and
Dunstable Brook, respectively. Some refuse lies beneath the
current early-spring water table in all areas of the landfill.
The saturated thickness of the refuse varies from negligible in
the east to over ten feet in the western area.
Contaminated groundwater in the eastern part of the site was
previously pulled southward and into deep bedrock from 1975
through 1982 when Cannongate's deep bedrock wells were in use.
The condominium's wells, 500 feet deep in bedrock, became
contaminated with volatile organic compounds (VOC's) as a result,
and were ordered closed by the Massachusetts Department of
Environmental Quality Engineering (DEQE) in 1982. Deep bedrock
groundwater remains contaminated in the Cannongate area and
northward to the landfill's eastern boundary at approximate depths
of 150-400 feet below ground surface. Since the cessation of
Cannongate's pumping, deep groundwater gradients have reverted to
an easterly direction at an estimated velocity of 20 feet per year.
More information on site characteristics, including air emissions
and sediment contamination is included in section five of this ROD.
II. Site Response & Enforcement History
A. Response History
EPA's involvement at the CGL began with groundwater testing,
conducted by EPA contractor Ecology and Environment, Inc. during
1981 and 1982. EPA also undertook emergency removal actions
beginning in August 1983 and continuing through March 1984. These
actions included the replacement of DEQE's temporary waterline to
Cannongate with another temporary but insulated waterline from the
North Chelmsford Water District. Other removal work included
construction of a security fence along the
northwestern entrance to the landfill, regrading and placement of
soil cover over exposed refuse, and installation of twelve gas
vents.
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As mentioned earlier, EPA has issued two previous RODs for
remedial operable units at the site. The first ROD, issued in
December 1983, selected an extension of an existing water supply
system to serve the Cannongate area. The new water line, an
extension of the City of Lowell's system, should be activated in
the Fall of 1988. The second ROD, issued in July 1985, selected a
full synthetic membrane landfill cap with surface water diversion,
off-gas collection and venting, and leachate seep collection. The
design for the cap and appurtenant systems has been completed, and
construction should begin in early 1989.
During its involvement with the CGL, EPA has undertaken various
site investigations and feasibility studies to explore the extent
and effects of contamination at the site and to evaluate
alternative remedies for each phase of cleanup. These studies,
listed chronologically, include:
1. Preliminary Site Assessment, (February 1981, Ecology and
Env i ronment, Inc.)
2. Field Investigations of Uncontrolled Hazardous Waste
Sites, Charles George Land Reclamation Trust, Final
Report (December 1982, Ecology and Environment, Inc.)
3. Water Supply Alternatives, Cannongate Area,
Tyngsborough, Massachusetts
a. Part 2 of 2 (September 1983, Fay Spofford &
Thorndike, Inc.)
b. Part 1 of 2 (October 1983, NUS)
4. "Remedial Action Master Plan (November 1983, NUS)
5. Source-Oriented Feasibility Study
a. Draft - March 1985, NUS
b. Final - November 1985, NUS
6. Feasibility Study on Treatment of Leachate from Charles
George Landfill (February 1986, Camp Dresser and McKee,
Inc.)
7. Wetlands Assessment, Charles George Landfill Site (June
1986, GCA Corp.)
8. Preliminary Remedial Investigation Report, Charles
George Site, Volumes I and II, (September 1986, NUS)
9. Zndangerment Assessment, Charles George Landfill
(January 1987, Planning Research Corp./Alliance
Technologies Corp.)
10. Remedial Investigation Report, Charles George Landfill
Site, Volumes I and II (July 1988, Ebasco/E.C. Jordan)
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11. Feasibility Study Report, Charles George Landfill Site
(July 1988, Ebasco/E.C. Jordan)
More information on EPA's cleanup history at the site can be found
on page 2-6 of the RI and page 1-3 of the FS.
B. Enforcement history
In 1982, 1983 and 1985, EPA notified parties who owned or operated
the landfill, arranged for the disposal of wastes at the landfill,
or transported wastes to the landfill, of their potential liability
with respect to the CGL. Information request letters were sent to
six of these parties in March 1984. In 1986, EPA notified fifty-two
additional parties who generated wastes that were shipped to the
facility of their potential liability with respect to the site.
The 52 potentially responsible parties (PRPs) have formed a
steering committee to represent them in their dealings with EPA.
The members of the Committee have been in close contact with EPA
since the Committee's inception by way of letters, telephone
conversations and meetings. Through said Committee, the PRPs have
been involved in the legal and technical discussion of the cleanup
work at the site.
The Steering Committee's technical subcommittee has met
regularly wi'ch EPA and DEQE, and has gained a full understanding
of the existing conditions at the site and the preferred cleanup
alternatives. Through these meetings the technical subcommittee
has presented to EPA and DEQE their ideas on cleanup alternatives.
In addition, the PRPs have submitted technical comments to EPA
during the public comment period. These comments have been
included in the administrative record for the site.
EPA has been in litigation with the first six noticed PRPs since
June 1985 for reimbursement of response costs, declaratory
judgement for future liability, voidance of fraudulent real
estate conveyances, and access to the site for implementation of
the second ROD. An access Order was issued by the court providing
for access to the site and surrounding properties by EPA and DEQE
for the implementation of the source-control (landfill capping)
remedy.
III. Community Relations
Through the site's history, community concern and involvement has
been high. LPA has kept the community and other interested
parties apprised of the site activities through informational
meetings, fact sheets, press releases and public meetings. Since
March 1988, EPA and the DEQE have met monthly with the local
citizens advisory committee.
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In August 1987, EPA released a revised community relations plan
which outlines programs-to address community concerns and to keep
citizens informed about and involved in activities during remedial
activities. The plans for the most recent RI and FS were
originally described at an informational meeting in Tyngsborough on
November 20, 1986.
The Agency published a public notice of upcoming public meetings
and a brief analysis of the Proposed Plan in both the Lowell Sun
and the Chelmsford Newsweekly on July 26 and July 28, 1988,
respectively. The Proposed Plan was also mailed out to 310
parties on EPA's mailing list for the site on July 21, 1988. On
July 22, 1988 the FS was made available to the public at the
Littlefield Public Library and at the Tyngsborough Town Hall.
Both volumes of the RI (narrative and appendices) were made
available to the public at the Littlefield Public Library by
August 4, 1988.
On August 3, 1988 EPA held a public informational meeting to
discuss the results of the RI and the cleanup alternatives
presented in the FS, as well as to present the Agency's Proposed
Plan. EPA also answered questions from the public during this
meeting. From August 4 through August 24, 1988 the Agency held a
three week public comment period to accept public comment on the
alternatives presented in the FS and the Proposed Plan and on any
other documents previously released to the public. On August 17,
1988, the Agency held an informal public hearing to accept any
oral comments. No oral comments were given at this hearing, but
EPA again explained the Proposed Plan and answered further
questions. A transcript of this hearing, and the Agency's
responses to written comments are included in the attached
responsiveness summary.
IV. Scope and role of -operable units and brief description of the
selected remedy
This ROD encompasses both the third and fourth operable units for
the CGL as defined by EPA. As such, the selected remedial actions
of this ROD represent the third and final phase of anticipated
cleanup at the site. The operable units for the site have been
defined as follows:
1. Provide alternative water supply for the Cannongate
area;
2. Control the source of contamination at the site;
3. Control the migration of contaminants from the site; and
4. Treat leachate collected as a result of the selected
source control remedy.
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Thus the focus of this ROD is on 'the control and cleanup of
contaminants that have spread or are spreading from the site,
including the treatment of leachate collected as part of the cap
system. Based on the evaluation criteria and viable options
discussed in detail in sections VIII-XII of this document, EPA
selected the three part remedy outlined below for the cleanup of
contaminated groundwater and leachate, landfill gas emissions and
stream sediment. The remedy is presented here to provide focus
for the reader during the following discussion.
1. Leachate collected from the landfill cap system will be
combined with contaminated overburden and shallow
bedrock groundwater and treated on site with biological
treatment, hydroxide precipitation, carbon adsorption,
and, if necessary, ion exchange water treatment units.
The treated leachate and groundwater will be monitored
and discharged into groundwater on-site, if feasible.
If not, the treated leachate and groundwater will be
discharged to a nearby approved surface water. An
upgradient groundwater diversion trench will also be
installed to assist in lowering the water table beneath
the landfill, thereby minimizing direct contact between
groundwater and landfill wastes. In addition,
groundwater monitoring will be performed to provide
early warning of possible increases in contaminant
concentrations that may impact residential drinking
wells in deep bedrock.
2. Landfill vent emissions will be collected and •
incinerated on site; and
3. Contaminated sediments in Dunstable Brook immediately
west of the landfill will be dredged, solidified on
site, and placed beneath the full synthetic cap that
will be constructed over the landfill per EPA's second
ROD.
As mentioned previously, construction of the landfill cap should
begin in early 1989. Collection of leachate could thus begin by
the end of 1989. Since it is possible that the phase III remedy
for leachate treatment will not be designed, constructed and
implemented within this time frame, some method of interim
leachate treatment and disposal may be required.
V. Site Characteristics
Section 3-3 of the FS contains an overview of the Remedial
Investigation, including the quantity and concentrations of
contaminants in groundwater, leachate, brook sediments and
landfill gas emissions. The significant findings of the RI are
summarized below.
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A. Groundwater
The RI identified three areas of contaminated groundwater which
warranted consideration for remedial action. These consist of
overburden groundwater in the southwestern area of the site;
overburden and shallow bedrock groundwater in the eastern area of
the site; and deep bedrock groundwater 150-450 feet deep in a
north-south plume stretching from the northeast boundary of the
landfill to the Cannongate area. These plumes are illustrated in
Figure 2, and the maximum contaminant concentrations found in each
plume during the 1987 remedial investigation are shown in Table 1.
Table 1 also lists concentrations of organic compounds detected in
southwestern shallow bedrock. The following paragraphs describe
these areas further.
1. Southwestern overburden and shallow bedrock groundwater
In overburden, the plume travels laterally relatively slowly at an
estimated 20-70 feet per year, and has been detected about 500
feet southwest of the landfill to the E & E/FIT 5 well area.
Depth to bedrock ranges from 10 to 20 feet, and surficial deposits
range from sandy glacial till to silty glacial till. Contaminant
levels in overburden measured during 1987 were approximately 50
percent lower than historical levels, with the exception of
benzene. Data indicate a trend of increasing overburden benzene
levels, from 31 ug/1 in 1985 to 229 ug/1 in 1987.
Shallow bedrock groundwater sampled from well MW-8 exhibits
organic contamination similar to overburden groundwater, with the
exception of benzene. Data from the one 1987 sample from well MW-8
indicate an estimated benzene concentration of 8 ug/1. Although
MW-s was analyzed for total metals rather than dissolved, arsenic
contamination appears to be less in shallow bedrock than overburden
(26 ug/1 total verses 249 ug/1 dissolved, respectively). Shallow
bedrock is characterized by small opening fractures rather than
large, high yield fractures, and its potentiometric surface (Figure
7-6 of the RI) strongly resembles the overburden water table
(Figure 7-4 of the RI). Contaminants in overburden and shallow
bedrock aquifers are expected to discharge primarily upward toward
Dunstable Brook, but some contaminated groundwater may pass beneath
Dunstable Brook and discharge at a more distant location from the
landfill. Deep bedrock groundwater (greater than 100 feet deep) is
not believed to be within the contaminant flow path.
Potential receptors include future well users living in or near
the now abandoned Hoare residence, and the biological communities
associated with the stream system across Dunstable Road. Leachate
seepage contributing to groundwater contamination in this plume
will be minimized once the landfill is capped, but if portions of
the refuse remain saturated the refuse will continue to be a
chronic source of contamination.
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2. Eastern overburden and shallow bedrock groundwater
Groundwater in the 20 foot tki£K sand and gravel overburden
aquifer underlying the eastern area travels laterally at
approximately 220 feet per year. This flow system discharges to
the Route 3 drainage system, Flint Pond Marsh, and possibly to
Flint Pond. The Route 3 drainage system ultimately discharges to
Flint Pond Marsh. Adequate time has already passed for
groundwater contamination to reach the Marsh and Pond. Present
contaminant concentrations in this aquifer are relatively low, but
deterioration and leakage of waste containers within the landfill
could cause contaminant concentrations to fluctuate markedly. In
the northeastern area of the landfill some refuse is saturated by
groundwater, but groundwater that just penetrates into the base of
refuse in the eastern area did not flow in sufficient quantities to
allow sampling. The closest drinking water wells to this plume are
located in the residential area on the northeast shore of Flint
Pond. Adverse impacts to these wells from CGL contaminants are
unlikely since contaminant concentrations in the plume moving
towards Flint Pond are low. Whatever contaminants that do
discharge into the pond are expected to be below detection limits.
Evidence for this is given by the results of the residential
drinking well and surface water monitoring discussed in sections
V.C and V.F of this document, respectively.
As Table 1 shows, shallow bedrock groundwater in the lightly
fractured zone at the top of the bedrock in this area is also
contaminated, at levels significantly higher than in the surficial
deposits. Although predicting specific routes of contaminant
transport in bedrock is difficult, water level data gathered for
overburden, shallow and deep bedrock monitoring wells suggest that
hydraulic gradients are downward at the eastern edge of the
landfill and upward in the vicinity of Flint Pond. Bedrock
groundwater would only be anticipated to discharge to Flint Pond
Marsh or Flint Pond if conductive fractures penetrate deep bedrock
zones with sufficient upward groundwater gradients.
3. Eastern deep bedrock groundwater
Contamination in deep bedrock groundwater exists along the eastern
edge of the landfill south to the Cannongate area at depths from
150 to over 450 feet below ground surface. As mentioned earlier,
this plume was drawn down and southward by the Cannongate
condominium wells. Natural eastward gradients and
flow rates of approximately 20 feet per year have been
reestablished since the condominium wells' inactivation in 1982.
Existing receptors in the Cannongate area will be eliminated with
the activation of the new water main. Identifying future
receptors is difficult due to the uncertainties associated with
predicting specific avenues of contaminant transport in bedrock,
and future pumping effects from outside of the immediate CGL area.
8
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Deep groundwater is not expected to rise at a steep enough
gradient to enter Flint Pond or the overburden aquifer, given the
low upward hydraulic gradient at well JDT-2. Some private deep
bedrock wells do exist along Middlesex Road over 4000 feet to the
east of the site, but contaminant concentrations should decrease
significantly, due to dilution, natural attention, and the
expected decades of travel time, before reaching these locations.
The neighborhood on the northeast shore of Flint Pond is not
considered a receptor, given the east to southeast deep
groundwater gradients detected along the eastern landfill boundary
and the lack of groundwater contamination in the area attributable
to the landfill. The Merrimack River is the inferred regional deep
groundwater discharge area.
A more detailed discussion of groundwater contamination at the
site can be found in Chapter 7 and section 11.2 of the RI.
B. Leachate
Above ground discharges of leachate occur at the CGL both as
seepage around the site, especially at the toe-of-slope, and as
discharges from the existing eastern and western collection
system. The western collection system includes a pump station
which recirculates the collected leachate into the western lagoon,
while leachate from the eastern system drains by gravity to the
eastern lagoon after by-passing an inoperable pump station.
Leachate existing as seeps discharge to various small wetlands and
intermittent brooks around the perimeter of the site.
Leachate from seeps and both existing collection systems will be
collected as part of the capping project, and thus will no longer
be a source of contamination to perimeter wetlands. This leachate
will, however, as defined by EPA's operable unit four, require
treatment after being collected. The leachate collection system
will be above the water table, and the quantity of leachate needing
treatment is estimated in the FS to be an average of 3600 gallons
per day (gpd). Initially, the flow rate should be higher, but as
the landfill drains down due to loss of recharge with capping this
flow rate should decrease. The maximum chemical concentrations
detected in leachate to date are listed in Table 2.
C. Residential drinking wells
Since 1983, EPA and the DEQE have been monitoring residential
wells in the vicinity of the site to ensure that residents are not
drinking contaminated well water. To date, 17 sampling rounds have
been conducted which have included in total more than 100 wells
located within one mile of the site. Analyses have concentrated on
the detection of organic compounds, and contaminants have not been
detected in most of the wells sampled to date. With the exception
of a few bedrock wells in the Cannongate area, concentrations of
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organic compounds have all been below 10 ppb. An .estimated mercury
concentration of 3200 ppb in May 1985 in a shallow well north of
the landfill is not considered to be site related since overburden
and shallow bedrock groundwater gradients (Figures 7-4 and 7-6 in
the RI) clearly demonstrate groundwater movement away from this
well towards the landfill. Mercury was not detected in this area
in October 1984 or May 1988.
Wells in the Flint Pond area in which organic compounds have been
detected have not shown the same presence of landfill contaminants
in subsequent sampling rounds. As discussed previously, these
wells are not expected to be impacted by groundwater contamination
from the landfill. The absence of repeat occurrences of landfill
contaminants in these wells suggests sources other than the
landfill.
D. Air Quality
Gaseous emissions from the landfill are generated throughout ±he
entire site.as a result of a biological and chemical processes
within the refuse. This landfill gas is estimated to be 50-
percent (by volume) methane, 40-percent carbon dioxide, and the
remaining 10-percent a mixture of other compounds including
hydrogen sulfide, mercaptans, and VOC's as listed in Table 3. The
maximum on-site VOC concentrations from three sampling episodes in
1984-85, 1986 and 1987 are also listed in Table 3. The landfill
gas is also characterized by a potent odor which has caused
numerous complaints from residents and motorists in the area. Site
observations and air sampling demonstrate that surface-based
gaseous emissions can be more significant than the vent emissions.
After capping, the landfill will continue to be a source of
gaseous emissions. The present cap design includes a passive,
crushed stone gas collection trench system under the cap liner
which will discharge to the atmosphere through twenty-eight new
vents to be constructed along the top of the landfill. The twelve
existing vents will be tied into the new gas collection system, and
then capped below the liner. Air quality computer modeling done as
part of the RI suggests that off-site
impacts could decrease after capping due to increased mixing,
dilution, and dispersion.
Present receptors include on-site trespassers as well as residents
in the surrounding neighborhoods, including north Flint Pond. VOC
concentrations detected off-site are shown in Table 4. Although
the entire site will be fenced as part of the capping project,
future impacts could result from on-site as well as off-site
exposure. Future trespassing cannot be ruled out given the close
proximity of the Cannongate neighborhood and the remote, wooded
characteristics of the site boundary in that area.
10
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E. Sediment
In the western landfill area, contaminated-sediments were detected
off-site in a small wetland on the northern boundary of the site
and in portions of Dunstable Brook downstream of the western pump
station. The small northern wetland (identified in the RI as JSED-
22) receives contamination via leachate seepage and surface runoff.
This area will be covered as part of the landfill capping project.
Approximately 500 feet in Dunstable Brook, including a small
tributary leading from the western pump station, receives
contamination via leachate seepage across and under Dunstable Road
and as a result of overflow from the western pump station during
down times. These sources will be eliminated upon construction of
the cap's leachate collection system.
The contaminants of most concern in Dunstable Brook and the
tributary consist of various polynuclear aromatic hydrocarbons
(PAH's) as listed in Table 5. Table 5 also lists sediment
concentrations of arsenic and cadmium detected in the Dunstable
Brook area. PAH's do not volatilize as readily as VOC's, and the
flow regime of the Brook should not cause sediment disruption and
significant downstream transport. Thus these contaminated
sediments are expected to remain in place subsequent to landfill
capping. The TS estimated that approximately 500 cubic yards (cy)
of Brook sediments require remediation.
To "the east of the landfill, contaminated sediments were detected
off-site in northern Flint Pond Marsh and to a lesser extent at
random sites in Flint Pond. Contamination in the Marsh sediments
consisted of various metals, especially arsenic at concentrations
up to 300 mg/kg, and VDC«s. Flint Pond sediments in several areas
contain a few VOC's and semi-volatile organic compounds (SVOC's),
low concentrations of lead and chromium, and low to moderate
concentrations of arsenic up to 110 mg/kg. Contaminant levels were
lower in 1987 than in 1984-85 for most of the sites that were
resampled. Also, similar concentrations of arsenic, lead,
chromium, acetone and SVOC's in two other Tyngsborough ponds
(Locust or Upton) beyond the influence of the landfill suggest high
background levels or additional contaminant sources.
The discharge of shallow groundwater from the previously discussed
eastern shallow plume has contributed contaminants to Flint Pond
Marsh, and possibly to Flint Pond. Again, this groundwater enters
the Marsh as flow under Route 3 and as seepage that enters the
highway's drainage system east of the eastern landfill lagoon.
This seepage then discharges to the Marsh through a culvert under
the highway. The highest concentration of arsenic detected in the
Marsh sediments (300 me/kg) was found near this culvert. The
average arsenic concentrations for Marsh sediments was an order of
magnitude lower at 30 mg/kg. This plume could continue to
introduce contaminants TO the Marsh after capping, especially if
barrels or other waste containers in the landfill corrode and
11
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release their contaminants. However, elimination of the eastern
lagoon and leachate seeps as a result of the cap will eliminate a
significant input of contaminants to the Marsh. The groundwater
draw down as a result of Cannongate's pumping most likely minimized
groundwater impacts on the Marsh, but future contributions from
rising shallow bedrock groundwater may occur since natural, locally
upward gradients have been reestablished.
F. Surface Water
The only organic contamination detected in Dunstable Brook, Bridge
Meadow Brook, Flint Pond Marsh or Flint Pond surface water during
the remedial investigation were very low levels of xylene in the
southwestern drainage swale within 500 feet of the landfill.
Aluminum was detected in three locations (Bridge Meadow Brook,
Flint Pond, and near the Hoare property) at concentrations less
than 1 mg/1, and cyanide was detected in one sample from Flint Pond
at 110 ug/1. On site, VOC concentrations in the landfill lagoons
were observed to be in the 104 ug/1 range in 1985, and in the 102
ug/1 range in 1987.
*
Sampling done by EPA in May 1988 also found only very low levels
of contamination in the southwestern swale immediately downstream
from the landfill. Landfill lagoon VOC concentrations, however,
were detected in the 104 ug/1 range in this sampling episode. VOC
concentrations in leachate are expected to vary seasonally, with
downstream contaminant migration occurring during periods of high
runoff. Construction of the landfill cap and the surface water
diversion system will eliminate this mechanism of contaminant
migration.
As mentioned previously, landfill contaminants can also be
transported to surface waters via groundwater discharge, with
Dunstable Brook, Flint Pond Marsh and possibly Flint Pond being
the principal receptors. Again, enough time has elapsed for
contaminants to reach the Marsh and Pond, but not enough to reach
Dunstable Brook. Groundwater modeling performed during the RI
predicted that once the southwestern plume does discharge to the
Brook) contaminant concentrations would be quickly diluted to
below detection levels.
VI. Summary of site risks and response objectives
The Endangerment Assessment completed by Alliance in January 1987
described the potential exposure and risks to human health and the
environment based on site data collected by NUS through 1985. The
baseline risk assessment done as part of the most recent remedial
investigation used this information as well as the 1987 data
generated during the RI to characterize future on- and off-site
risks subsequent to landfill capping.
12
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Thirty-one contaminants of concern, listed in Table 6, were
selected for quantitative evaluation in the risk assessment.
These contaminants constitute a representative subset of the more
then sixty contaminants identified at the site during the RI. The
thirty-one contaminants were selected to represent potential
on-site and off-site risks based on their toxicity, concentration,
prevalence, and persistence in the environment.
Potential human health effects associated with the contaminants of
concern as a result of exposure to these contaminants in
groundwater, landfill gas emissions, surface water, biota and
sediments were estimated quantitatively through the development of
several hypothetical exposure scenarios. Incremental lifetime
cancer risks and a measure of the potential for noncarcinogenic
adverse health effects were estimated for the various exposure
scenarios. The exposure scenarios were developed to reflect the
potential for exposure to hazardous substances based on the
characteristic use and location of the site. The results of the
risk assessment are summarized in Table 7. Carcinogenic risks are
considered acceptable by EPA if the computed total incremental
carcinogenic risk (ICR) for an individual, predicted as a result of
possible exposure to contaminants originating from a Superfund
site, is below 1x10~4. The threshold for acceptable non-
carcinogenic risks is usually a hazard index between 1 and 10. The
Hazard Index is the term used to describe the ratio between an
exposure dose (expressed in mg/kg/day) and a relevant contaminant
specific non-carcinogenic guideline such as the reference dose.
The carcinogenic and non-carcinogenic risks are presented in Table
7 by media and exposure scenario.
Given these results of the risk assessment, guidelines in the
Superfund Public Health Evaluation Manual (EPA, IS'86) were then
used to assist EPA in the development of response objectives.
These objectives were developed to mitigate existing and future
threats to human health and the environment. These response
objectives are:
Reduce potential future human health risks from
ingesting benzene and arsenic in overburden
groundwater southwest of the landfill.
Reduce potential human health risks from benzene,
arsenic, bis (2-ethylhexyl) phthalate, and
trichloroethene in deep bedrock groundwater east of the
landfill, with respect to use as a drinking water
supply.
Remediate shallow eastern groundwater to comply with
Safe Drinking Water Act (SOWA) maximum contaminant
levels (MCL's) and Resource Conservation and Recovery
Act (RCRA) groundwater corrective action requirements
(40 CFR §264.92-100).
13
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Reduce potential human health risks posed by bromoform
and various carcinogenic contaminants in landfill vent
emissions (primarily, 1,1-dichloroethene, 1,1,2,2-
tetrachloroethane, vinyl chloride, methylene chloride,
and carbon tetrachloride).
Reduce potential human health risks from PAHs in
sediments vest of Dunstable Road in the leachate
drainageway to Dunstable Brook, as well as short reaches
of Dunstable Brook itself.
Finally, since this cleanup phase includes operable unit four as
well as three (see section P7), response objectives include the
treatment of leachate collected from the landfill cap's leachate
collection system.
As a result of these response objectives, target cleanup levels
were developed for the southwestern shallow aquifer, the eastern
shallow bedrock and overburden aquifers, the Dunstable Brook
sediments, and the landfill vent emissions. These target cleanup
levels were developed to protect human health and the environment
in the areas of concern, and are based on the results of the risk
assessment or on applicable or relevant and appropriate regulatory
requirements (ARARs). Table 8 lists the cleanup levels for the
respective areas of concern, and also shows whether "the cleanup
level is risk—based or ARAR-based.
."711. Documentation of Significant Changes
"EPA adopted a preferred alternative for remediation of shallow
groundwater and leachate, landfill gas, and contaminated sediments
at the site in the Proposed Plan issued on July 21, 1988. The
preferred alternative for groundwater and leachate was extraction
of contaminated southwestern and eastern shallow groundwater
plumes, and combined treatment of the extracted groundwater with
leachate collected from the cap system. The treatment system
included biological treatment and would have discharged to
Dunstable Brook. The preferred alternative for the landfill gas
was collection and incineration of vent emissions, while for
sediments the preferred alternative was excavation, solidification
and landfill capping. The preferred alternative also included off-
site deep bedrock groundwater and residential well monitoring.
The selected remedies of this ROD are identical to the preferred
alternatives of the Proposed Plan, except that the final discharge
of treated groundwater and leachate will be to groundwater rather
than to Dunstable Brook, if feasible. This is not a significant
difference because the groundwater and leachate will be treated by
the same technologies and to the same standards as in the Proposed
Plan. In fact, groundwater reinjection will offer some natural
attenuation to the treated discharge. It was not preferred in the
Proposed Plan because an appropriate groundwater reinjection
14
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location with sufficient capacity for accepting the discharge had
not been identified with absolute certainty. In order to get State
approval of a Dunstable Brook discharge, however, a variance to thd
State's surface water anti-degradation policy would be needed. ThJ
variance would require that all other alternatives to a Dunstable
Brook discharge be infeasible. Thus further evaluation of a
groundwater reinjection discharge is required.
There are deep bedrock wells to the north and southeast of the
site that are strong candidates for reinjection wells. During
remedial design, these areas and others will be assessed in detail
to determine if groundwater reinjection is feasible and
appropriate. If it is found to be infeasible or inappropriate,
the treated discharge will be to a surface water, either Dunstable
Brook, Bridge Meadow Brook or the Merrimack River, approved by both
the State and EPA. Again, a variance from the State's surface
water anti-degradation policy would be needed for approval of a
discharge to either of the brooks. Appropriate surface water
discharge requirements will be developed if it is determined
necessary to discharge to surface water rather than groundwater.
VIII. Development and screening of response alternatives
A. Statutory requirements
Prior to the passage of the Superfund Amendments and
Reauthorization Act of 1986 (SARA), actions taken in response to
releases of hazardous substances were conducted in accordance with
CERCLA as enacted in 1980 and the revised National Oil and
Hazardous Substances Pollution Contingency Plan (NCP), 40 CFR Part
300, dated November 20, 1985. Until the NCP is revised to reflect
SARA, the procedures 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
practicable, 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 (ARARs)
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 preference 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
15
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treatment. Response alternatives were developed to be consistent
with these Congressional mandates.
B. Technology and alternative development and screening
CERCLA, the NCP, and EPA guidance documents (including "Guidance
on Feasibility Studies Under CERCLA" dated June 1985, and the
"Interim Guidance on Superfund Selection of Remedy", EPA Office of
Solid Waste and Emergency Response, Directive No. 9355.0-19 dated
December 24, 1986) set forth the process by which remedial actions
are evaluated and selected. In accordance with these
requirements and guidance documents, treatment alternatives were
developed for the site ranging from alternatives that, to the
degree possible, would eliminate the need for long-term management
(including monitoring) at the site to alternatives 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, no-action and, when
possible, containment alternatives were developed for each affected
media in accordance with Section 121 of CERCLA.
Section 121(b)(l) of CERCLA presents several factors that, at a
minimum, EPA is required to consider in its assessment of
alternatives. In addition to these factors and the other
statutory 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. Compliance with applicable or relevant and appropriate
requirements (ARARs);
2. Long-term effectiveness and permanence;
3. Reduction of toxicity, mobility or volume;
4. Short-term effectiveness;
5. Implementability;
6. Community acceptance;
7. State acceptance;
8. Cost; and
9. Overall protection of human health and the environment.
16
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Chapters four, five, and six of the FS identified, assessed and
screened response technologies based on effectiveness and
implementability. The effectiveness assessment considered the
degree to which technologies achieved cleanup target levels and
complied with applicable or relevant and appropriate requirements
(ARARs). The implementability assessment considered the technical
feasibility, demonstrated performance, and availability of major
component pieces of each technology identified. This initial
screening was performed on groundwater and leachate alternatives,
sediment alternatives, and landfill gas alternatives. Its purpose
was to narrow the number of potential remedial actions for further
detailed analysis while preserving a range of options. Remedial
alternatives for groundwater and leachate, -sediment, leachate only,
and landfill gas were then evaluated in detail in chapters 7,8,9
and 10 of the FS, respectively, based on effectiveness,
implementability and cost. Leachate remedies were analyzed both
with groundwater and separately in the event that the "no-action"
groundwater alternative were to be selected for operable unit
three. In summary, of the nineteen alternatives originally
developed in Chapter 5, sixteen were retained for detailed
analysis. Table 9 lists the technologies originally identified in
Chapter 4; and identifies the alternatives that were subsequently
eliminated in Chapter 4; the alternatives that were eliminated in
Chapter 6's initial screening; and the alternatives that were
retained for detailed analysis.
IX. Description and summary of the detailed analysis of
alternatives
This section presents a narrative summary of each alternative
evaluated in the detailed analyses chapters of the FS. A tabular
assessment of each alternative based on the previously mentioned
nine criteria is presented in Table 10. Both the narrative
summary and Table 10 are arranged by media.
A. Leachate and groundwater alternatives
1. No action (GW-1)
The "no-action" alternative provides a baseline against which
other alternatives can be compared. Landfill leachate would be
treated separately if the no-action alternative were selected for
groundwater. The no-action alternative would include a ground-
water monitoring program in which samples would be collected and
analyzed four times a year. Because contaminants would continue
to migrate from the site in this alternative, EPA would review
site conditions every five years to determine whether additional
remedial actions were necessary to protect human health and the
environment. This alternative requires no treatment technology
and thus could be readily implemented. However, it would not be
effective in protecting human health and the. environment, would
not reduce the toxicity, mobility, or volume of the site
17
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contaminants, and, as explained in Table 10-Criterion 7, would not
comply with SDWA and RCRA ARARs. The present worth costs listed
below, and those for the remaining leachate and groundwater
alternatives, are based on ten percent interest and thirty years of
operation.
Estimated Time for Construction and Operation: 30 Years
Estimated Capital Cost: $151,000
Estimated Annual Operation and Maintenance Cost: $113,000
Estimated Present Worth: $1,216,000
2. Extraction, carbon adsorption, and discharge (GW-2)
This alternative would entail extraction of shallow groundwater to
the east and southwest of the site, as well as deep bedrock
groundwater to the east of the site. Leachate from the landfill
cap system would be combined with the extracted groundwater and
treated on site to remove metals and organic compounds. For this
alternative, the treatment process would include hydroxide
precipitation, carbon adsorption, and, if necessary, ion-
exchange. Treated groundwater and leachate would be discharged
via pipeline to Dunstable* Brook or the Merrimack River, or
reinjected into groundwater. As discussed briefly in section IV
and in more detail in sections X and XI, the selected discharge
option is groundwater reinjection, if feasible. However, since
the feasibility and costs of a groundwater discharge will be
developed during remedial design, the costs presented below and
for the next two alternatives are based on discharge to Dunstable
Brook. The relative difference in costs for these alternatives
will be the same, though, since discharge costs, regardless of the
discharge location, will be the same for each alternative.
This alternative would protect human health and the environment by
reducing risks of exposure to contaminated groundwater, and would
permanently and significantly reduce the volume, mobility, and
toxicity of the groundwater contaminants. The extraction of
contaminated groundwater would attain SDWA and RCRA ARARs, and the
treated discharge would meet Clean Water Act (CWA) discharge
requirements as required by the National Pollutant Discharge
Elimination System (NPDES). The treatment technologies used in
this alternative are well proven, reliable, and would be easy to
implement. Construction of a discharge pipeline, however, would
cause some negative environmental impacts due to temporary
disruption of wildlife habitats. Moreover, acetone, 2-butanone
and benzoic acid, three aqueous contaminants of concern expected
at significant concentrations, would not be as amenable to removal
with this alternative as compared to the selected remedy.
Estimated time for Design and Construction: 2 1/2 years.
Estimated Time for Operation: 5-55 years
Estimated Capital Cost: $2,995,000
Estimated Annual Operation and Maintenance Cost $ 686,000
18
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Estimated Total Present Worth Cost: $9,809,000
3. Extraction, air stripping, carbon adsorption and discharge
(GW-3)
This alternative is similar to Alternative 2 above, except that
air stripping would be added to the treatment process.
Approximately one-half the amount of activated carbon would be
needed as a result. This alternative would permanently reduce the
mobility, toxicity, and volume of contaminants; would meet SDWA,
RCRA, and CWA ARARs as well as state allowable atmospheric ambient
levels (AAL's); and would provide long-term protection of public
health and the environment. This alternative could be readily
implemented, although construction of a discharge outfall would
pose some temporary negative environmental impacts. This
alternative poses potential risks to human health throughout its
implementation due to emissions of vapor phase vocs from the air
stripping process. These emissions could conceivably be tied into
a landfill gas treatment system, however. As with Alternative 2,
this alternative could present problems in
removing acetone, 2-butanone and benzoic acid.
Estimated Time for Design and Construction: 2 1/2 years
Estimated Time for Construction and Operation: 5—55 years
Estimated Capital Cost: $2,893,000
Estimated Annual Operation and Maintenance Cost: $695,000
Estimated Total Present Worth Cost: $9,792,000
4. Extraction, biological treatment, carbon adsorption and
discharge (GW-5)
This alternative is also similar to Alternative 2 above, except
that biological treatment would be added as the first step of the
treatment process. Estimated activated carbon usage would be
reduced to approximately four pounds per day (ppd) compared to 100
ppd and 50 ppd for Alternatives 2 and 3, respectively. As with
these other alternatives, some negative environmental impacts would
result due to the temporary disruption of wildlife habitats during
construction of a discharge outfall. Treatment residuals would be
increased by approximately fifteen percent, by weight,, as compared
to alternatives 2 and 3, but otherwise this alternative could be
readily implemented. It would permanently reduce the mobility,
toxicity, and volume of contaminants; would meet RCRA, SDWA and CWA
ARARs; and would provide long-term protection of public health and
the environment. In contrast to Alternatives 2 and 3, this
alternative should readily remove acetone, 2-butanone and benzoic
acid. For reasons explained in section XI, the treatment
technology of this alternative is the selected remedy's technology
for the treatment of groundwater and leacaate. The selected remedy
differs somewhat from this alternative, however, since it: a)
requires groundwater monitoring rather than extraction and
19
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treatment for the eastern deep bedrock plume; and b) selects final
discharge to groundwater rather than Dunstable Brook, if feasible.
Estimated Time for Design and Construction: 2 1/2 years
Estimated Time for Operation: 5-55 years
Estimated Capital Cost: $3,318,000
Estimated Annual Operation and Maintenance Cost: $593,00
Estimated Total Present Worth Cost: $8,800,000
5. Extraction, off-site treatment, and discharge (GW-6)
For this alternative, extracted groundwater and leachate would be
piped to on-site storage tanks and then transported off site to an
EPA-permitted hazardous waste facility using tanker trucks. This
alternative would provide long-term protection of public health and
the environment, and would comply with SOWA and RCRA ARARs. This
alternative is technically feasible, but it would require long-term
contracts with licensed firms to transport and treat the wastes.
These contracts and thus the reliability of this alternative could
be jeopardized by potential noncompliance of the off-site treatment
facility. Some health risks to workers would be posed by
transportation of the contaminated groundwater and leachate, and
truck traffic to and from the site would continue through the
entire.period of implementation. Costs for this alternative are at
least one order of magnitude higher than costs for the other
groundwater and leachate alternatives.
Estimated Time for Design and Construction: 1 1/2 years
Estimated Time for Construction and Operation: 5-55 years
Estimated Capital Cost: $1,861,000
Estimated Annual Operation and Maintenance Cost: $12,256,000
Estimated Total Present Worth Cost: $ 117,397,000
B. Landfill gas alternatives
1. No action (GAS-1)
In this alternative, landfill gas would be discharged directly to
the atmosphere without treatment. Since the gases would be
emitted from the landfill vents that will be constructed as part
of the landfill cap, there would be no immediate cost associated
with this alternative. Significant on-site risks to human health
and the environment would remain unmitigated. This alternative
would most likely not attain Massachusetts' allowable ambient
levels (AAL's), and would not reduce the toxicity, mobility, or
volume of contaminants. As required by SARA, EPA would review
this alternative every five years to determine whether remedial
action is necessary.
2. Gas flaring (GAS-3)
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In this alternative, gas emissions from the landfill vents would
be collected and treated with gas scrubbers to remove acidic
compounds and then piped to an on-site gas flaring unit. The
flaring unit would burn the landfill gas directly and, after
initial startup, would be fueled by methane contained in the
landfill gas emissions.
Flaring technology has been used to burn conventional landfill gas
but is not as well demonstrated for mixed waste sites. Pilot-scale
tests would be required to determine the efficiency of the system
in destroying the specific compounds present at the Charles George
site. This alternative and the following two alternatives would
produce secondary air pollutants from the combustion process, but
these would contain significantly less contaminants then the
current level of emissions. Nevertheless, scrubbing or similar air
treatment technology would be installed after flaring if air
monitoring demonstrates non-compliance with Clean Air Act (CAA)
national secondary ambient air quality standards (NAAQS). Thus CAA
ARARs would be attained. Also, gaseous landfill contaminants
should be well below state AAL's upon transport to off-site
residential areas. Risks due to inhalation of landfill gas and
nuisance odors would be reduced, but EPA's on-site risk-based
target cleanup levels may not be attained. Also, the wastewater
sidestream from the pre-flaring scrubber would require treatment
throughout the operation of the flare. The present worth costs
listed below and those for the remaining landfill gas alternatives
include design, construction and operating costs, and are based on
ten percent interest and thirty years of operation. Since design
costs are included, the total present worth cost for each
alternative will be different than as listed in the FS.
Estimated Time for Design and Construction: 13 months
Estimated Time for Operation: 20-30 years
Estimated Capital Cost: $237,000
Estimated Annual Operation and Maintenance Cost: $37,000
Estimated Total Present Worth Cost: $586,000
3. Incineration (GAS-4)
In this alternative, gas emissions from the twenty-eight (28)
future landfill vents would be collected and incinerated on site.
Complete combustion within the incinerator would be sustained by
blowing 3000-5000 cubic feet per minute (cfm) of air into it. No
pretreatment would be required, but auxiliary fuel would initially
be necessary to fire the incinerator to operating temperatures
above 1,200'F. Thereafter, methane in the landfill emissions would
fuel the combustion. The incinerator would discharge directly to
the atmosphere, unless scrubbing or other air treatment
technologies are demonstrated to be required.
Incineration is a proven technology for treating gaseous streams
containing both conventional landfill gases and hazardous
21
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compounds. Some secondary air pollutants would be generated by
the combustion process. However, incinerators have demonstrated
VOC removal rates above ninety-nine percent, and attainment of
such efficiencies would achieve all the target vent emission
cleanup levels. Nuisance odors would be minimized, and off-site
gaseous VOC levels from the landfill should be below AAL's. Thus
incineration would protect human health and the environment in
both the short and long term, and would provide a permanent
reduction in air-borne site contamination. For reasons explained
in section XI, incineration is the selected remedy for the
management of landfill gas emissions.
Estimated Time for Design and Construction: 16 months
Estimated Time for Operation: 20-30 years
Estimated Capital Cost: $685,000
Estimated Annual Operation and Maintenance Cost: $8,000
Estimated Total Present Worth Cost: $1,034,000
4. Combustion/Medium Btu gas recovery (GAS-5)
In this alternative, approximately twenty-four deep gas wells
would be installed within the landfill boundaries to extract the
gases generated by the landfill. Gas from these wells and from
the landfill vents would be passed through a scrubber to remove
acidic gases, and then burned in an internal combustion engine to
generate electricity. Exhaust gases from the combustion process
would be discharged directly to the atmosphere, unless scrubbing
or other air treatment technologies are demonstrated to be
required.
This alternative's technology has been proven for burning
municipal landfill gases, but not for sufficiently treating
hazardous substances. This technology could also be more prone to
corrosion failure and down time compared to flaring and
incineration. As with these other gas treatment alternatives,.
some secondary air pollutants would be generated. This
alternative would provide some protection of human health and the
environment, but it would not be as protective as gas flaring or
incineration. Based on estimated removal rates, EPA's target
cleanup levels would not be achieved for over half of the
contaminants of concern.
Drilling of the deep gas wells would initially contribute to air
quality problems, and could delay completion of the landfill cap.
Seams between the deep gas wells and the synthetic landfill cap
could increase the potential for leakage through the cap, and post
closure operation and maintenance costs could be increased.
Estimated Time for Design and Construction: 17 months
Estimated Time for Operation: 20-30 years
Estimated Capital Cost: $1,658,800
Estimated Annual Operation and Maintenance Cost:
$90,000 in revenue per year
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Estimated Total Present Worth Cost: $809,000
C. Sediment alternatives
1. No action (SED-1)
In the no action alternative, contaminated sediments would remain
in place and untreated in Dunstable Brook. As required by SARA,
EPA would review site conditions every five years to determine
whether remedial action is necessary. Public health risks expected
to be significantly above a 1x1O-6 incremental cancer risk in the
most probable exposure scenario would remain unmitigated, and there
would be no reduction in the toxicity, mobility or volume of
contaminated sediments. There are no costs associated with this
alternative.
2. In-site capping (SED-2)
This alternative would cover contaminated sediments located in the
Dunstable Brook tributary immediately west of the landfill and in
portions of Dunstable Brook. The cover would consist of a
synthetic fabric filter placed directly over the contaminated
sediments and a four-to-six inch layer of crushed stone placed on
top of the fabric layer. This alternative is technically feasible
and would reduce the mobility of PAH contaminants. This
alternative would protect human health by preventing direct
contact with contaminated sediments. It would protect the
environment to the extent that sediments would be prevented from
moving downstream from the capped area, but it would not prevent
contaminants from entering grouhdwater. In addition, installation
of the cap would cause adverse impacts to aquatic and terrestrial
habitats. Since the following sediment alternatives offer less
impacts to these habitats, this alternative would not comply with
CWA § 404 ARARs.
Estimated Time for Design and Construction: 6 months
Estimated Period of Operation: 30 year lifetime of cover materials
Estimated Capital Cost: $ 98,300
Estimated Annual Operation and Maintenance Cost: $ 4,900
Estimated Total Present Worth Cost: $ 144,200
3. Excavation and on-site disposal (SED-7)
This alternative and the remaining sediment alternatives would
entail excavating approximately 500 cubic yards (cy) of
contaminated sediments in Dunstable Brook and the tributary from
the western pump station down to a depth of approximately one
foot. Excavation machinery on land would be used as explained in
Chapter 8 of the FS. In this alternative, the excavated sediments
would then be placed on the landfill prior to construction of the
landfill cap. Completion of the cap over the sediments would
reduce further contaminant migration.
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Implementation of this alternative and the remaining alternatives
would pose some short-term environmental risks due to the
excavation process. Oil booms and silt screens would thus be used
during dredging to minimize PAH migration downstream due to
sediment resuspension. The impacted areas would also be restored
to their original condition. Thus this alternative would meet CWA
and Executive Order 11990 (EO 11990) ARARs (see section XII.B),
and would provide long-term protection of human health and the
environment. However, construction requirements for fill material
to be used during capping may not be attained.
Estimated Time for Construction and Operation: 3-6 months
Estimated Total Cost: $40,800
4. Excavation, solidification and on-site disposal (SED-3)
This alternative is similar to the previous alternative except
that the excavated sediments would be solidified on site before
being placed on the landfill for capping. Solidification entails
mixing the sediments with standard setting agents and silicate-
based additives to produce a granular soil-like material of low
solubility. Some bench-scale testing of additives would be
necessary to determine if. any are effective in immobilizing PAH's.
Solidifying and capping the sediments could minimize PAH migration
more so than capping only, and the solidified sediments would
attain construction requirements for fill material. This
alternative meets ARARs and would provide long-term protection of
human health and the environment.
Estimated Time for Design and construction: 3-6 months
Estimated Total Cost: $79,000
5. Excavation, thermal aeration, and on-site disposal
(SED-4)
This alternative is similar to the previous alternative, except
that the sediments would be treated by thermal aeration rather
than by solidification. Hot air would be forced through the
sediments to cause PAHs and other organic compounds to volatilize.
The contaminated air would be passed through an air pollution
control system to remove the contaminants before being released to
the atmosphere. The treated sediments would then be disposed on
site prior to landfill capping.
Thermal aeration has been demonstrated, on a pilot scale, to be
effective in removing PAHs. This alternative would reduce the
toxicity, mobility, and volume of contaminated sediments more so
than the previous sediment alternatives. On-site thermal aeration
would meet CWA, EO 11990 and CAA ARARs, and would provide long-term
protection of public health and the environment. This alternative
would cost significantly more than all the other sediment
alternatives, except off-site incineration (SED-6).
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Estimated Time for Construction and Operation: 3 to 6 months
Estimated Total Cost: $915,000
6. Excavation, off-site solidification and disposal
(SED-5)
In this alternative, contaminated sediments would be excavated and
placed in drums. The drummed sediments would be transported by a
licensed hazardous waste hauler to an EPA-permitted hazardous waste
treatment facility for solidification and disposal. This
alternative could be readily implemented, would meet RCRA, CWA and
EO 11990 ARARs, and it would provide long-term protection of human
health and the environment by removing contaminated sediments from
the site vicinity. By solidifying the sediments at the off-site
disposal location, the mobility of the contaminants would be
reduced. Some short-term environmental and human health risks
would be associated with excavation and transportation of the
contaminated sediments. This is the third most expensive sediment
alternative, and it would not respect CERCLA's statutory preference
for on-site treatment.
Estimated Time for Construction and Operation: 6 months
Estimated Total Cost: $208,500
7. Excavation, incineration, and off-site disposal (SED-6)
In this alternative, contaminated sediments would be excavated and
transported to an EPA-permitted hazardous waste facility for
incineration. Incineration would destroy organic compounds by
burning the sediment at a temperature up to 2,400'F, depending on
the type of incinerator used. The exhaust gases from the
incinerator would be passed through air pollution control devices
to remove particulate matter and acidic gases before being
released to the atmosphere. Incineration has been demonstrated to
be a reliable method of destroying organic compounds. This
alternative would meet RCRA, CWA, EO 11990 and CAA ARARs, would
permanently reduce the toxicity, mobility, and volume of the
sediment contaminants, and would protect human health and the
environment. Some short-term environmental and human health risks
would be associated with the excavation and transportation of the
contaminated sediments. This is the most expensive sediment
remedy, and it would not respect CERCLA's statutory preference for
on-site treatment.
Estimated Time for Construction and Operation: 3 to 6 months
Estimated Total Cost: $1,404,800
X. The selected remedy
The following selected remedy for the management of contaminant
migration and treatment of leachate represents the remaining
anticipated cleanup measures necessary for the Charles George
Landfill. Combined with the water supply and source control
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(landfill capping) remedial actions, implementation of the phase
III remedy will effect a, comprehensive response to the release of
contaminants at the site. The selected remedy for groundwater,
leachate, gaseous vent emissions, and off-site sediments is
detailed below.
A. Groundwater and leachate remedy
Leachate collected on-site as part of the landfill cap system will
be combined with contaminated overburden and shallow bedrock
groundwater and treated on-site with biological treatment, metals
precipitation, carbon adsorption and, if necessary, ion exchange
treatment units. The treated leachate and groundwater will be
monitored and discharged into groundwater on site, if feasible. If
not, the discharge will be to a nearby approved surface water.
An upgradient groundwater diversion trench will also be installed
to assist in lowering the water table beneath the landfill, thereby
minimizing direct contact between groundwater and landfill wastes.
In addition, groundwater monitoring will be performed to provide
early warning of possible increases in contaminant concentrations
that may impact residential drinking wells.
As discussed earlier in Section IV, some interim leachate
management should be necessary since collection of leachate as
part of the source control remedy will most likely begin before
implementation of this groundwater and leachate treatment remedy.
As recommended in the Feasibility Study on Treatment of Leachate
front Charles George Landfill (COM, 1986), this interim leachate
will be transported off-site for treatment at an EPA-permitted
hazardous waste treatment facility. This alternative is the most
practicable and protective solution given the time constraints
involved. Other alternatives developed during construction of the
landfill cap, such as leachate holding lagoons, will be considered,
however. In any event, construction measures should be taken
during installation of the landfill cap leachate collection system
to minimize the construction-phase collection of water runoff and
precipitation infiltration.
The details of the extraction systems and diversion trench will be
finalized during the design phase of the remedy. The upgradient
diversion trench should be carefully designed so that the trench
will intercept clean overburden groundwater only. If the trench is
installed too deep, it may draw contaminated groundwater from the
landfill. Based on existing geologic and hydrogeologic data, the
trench should be: a) approximately 700 feet long; b) located 250
to 350 north of the landfill (see Figure 7-2 in the FS); and c)
installed with a bottom elevation greater than 204 feet mean sea
level. The eastern contaminated groundwater extraction system
should, if possible, have the capability to independently withdraw
overburden and shallow bedrock groundwater, since the eastern
overburden aquifer could possibly attain cleanup levels before the
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eastern shallow bedrock aquifer. For the southwestern extraction
system, more monitoring of shallow bedrock groundwater will be done
to verify that this hydrologic unit does not warrant remediation.
If this monitoring indicates unacceptable risks (as defined in
Section VI) from carcinogenic or noncarcinogenic contaminants,
however, the southwestern extraction system will be designed to
remediate shallow bedrock groundwater as well as overburden
groundwater.
The extracted groundwater will be combined with leachate collected
as part of the cap system, and will be treated on-site to attain
the discharge levels listed in Table 11. Bench-scale or pilot-
scale testing of the selected treatment system using
representative leachate and groundwater samples should be
performed during remedial design to ensure that all the unit
processes are necessary, and that the discharge levels are
achieved in a cost-effective manner. This testing could
demonstrate that replacement or rearrangement of unit processes,
or that separate treatment schemes for leachate and groundwater,
are more cost-effective in meeting discharge requirements. The
final design will take these results into consideration, thus the
treatment system could conceivably be different than as outlined on
page 26.
After effluent monitoring to determine compliance with discharge
requirements, the treated groundwater and leachate will be
discharged into groundwater on site, if feasible. More
hydrogeological investigation will be performed during remedial
design to determine if a groundwater discharge is appropriate and
feasible. If groundwater discharge is found to be inappropriate
or infeasible, the treated groundwater and leachate will be
discharged to a surface water approved by the Commonwealth and
EPA. If a surface water discharge is needed, appropriate discharge
levels will be developed during remedial design for approval by the
Commonwealth and EPA. The clean diverted upgradient groundwater
will be discharged as appropriate.
Side streams generated from the treatment process will require
treatment or disposal. Spent activated carbon from the carbon
adsorption process and spent regeneration solution and resin beds
from the ion exchange process, if used, can be transported off-
site for reprocessing or disposal by equipment vendors. Waste
activated sludge from the biological treatment process and
hydroxide sludge from the precipitation process, if used, will be
dewatered onsite and properly disposed as a hazardous waste
according to Subtitle C of the Resource Recovery and Conservation
Act (RCRA). During remedial design, the feasibility of
constructing an extension to the CGL for the disposal of these
sludges will be evaluated. If it is determined that a secure
extension to the landfill, complete with the minimum technology
requirements of 40 CFR § 264.301, is not feasible or cost-
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effective, than these sludges will be disposed of in an off-site
Subtitle C landfill.
The groundvater monitoring to be performed as part of this remedy
will be in addition to the post-closure groundwater monitoring
required by EPA's second ROD. The post-closure monitoring will
focus on groundwater surrounding the landfill to assess effects of
the landfill cap, whereas the Phase III groundwater monitoring will
focus on detecting potential but unexpected contamination in both
groundwater monitoring wells and residential drinking wells further
off site. As the second ROD mentions, however, implementation of
the off-site groundwater monitoring can be incorporated into the
post-closure groundwater monitoring plan.
The details of the off-site groundwater monitoring will be
developed during remedial design. A list of approximately forty-
five off-site wells to be monitored once per year will be
generated. A representative subset of these wells will be sampled
quarterly for a minimum of 5 years in order to estimate seasonal
variations in contaminant concentrations. The well list should
focus on bedrock wells in the area, including wells 9, 11, 12, 27,
29, 53, 56, 57, 58, 59, 63, 66, 67, 70, 72, 84 and 88 as defined in
Table B-15 of volume II of the RI, as well as shallow wells in the
Dunstable/Red Gate Road Area, the Dunstable Road/Blodgett Street
area, and the Flint Pond area. Wells not on the list but in the
defined area and in similar groundwater zones can be substituted
into the monitoring program if needed. Future remedial actions
including extensions to the new waterline will be considered if the
monitoring program determines that landfill contaminants could pose
unacceptable risks to human health via residential drinking wells.
Implementation of institutional controls to prevent future use of
the contaminated deep bedrock aquifer, especially large yield
pumping, would increase the protectiveness of the remedy. EPA
will work with State and local officials to assist in determining
appropriate controls and in evaluating potential impacts from
development proposals involving large yield pumping.
B. Vent emission remedy
Landfill vent emissions from the twenty-eight landfill vents to be
constructed as part of the landfill cap will be collected and
incinerated on-site in a fume incinerator. During initial
startup, auxiliary fuel will heat the incinerator to oxidation
temperatures above 1,200*F. This temperature will be sustained by
using methane in the emissions as fuel. Landfill gas constituents
will be oxidized in the incinerator's central chamber. To prevent
leaks to the atmosphere, an exhaust fan downstream of the
incinerator will act as vacuum prior to oxidation.
Condensation/acid-scrubbing will not be required prior to
incineration, and the fan design and operation will allow proper
retention time for contaminant combustion in the central chamber.
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Incineration of vent emissions will continue for as long as
necessary to mitigate health risks.
Remedial design of the gas emission remedy should start with the
design of the gas collection system. This will allow for cost and
time savings if construction of the manifold system can be
incorporated into the upcoming construction of the landfill cap
and gas venting system. Also, the design of the collection and
incineration system should provide for mitigating measures such as
modular incinerator units or maximized atmospheric dilution in the
event the primary incinerator experiences down time. The design
should also provide for gas sampling throughout the collection
system and at the stack.
Combustion parameters such as temperature, carbon monoxide, carbon
dioxide, oxygen and total hydrocarbon concentrations will be
continuously monitored to provide an indication of the contaminant
destruction efficiency of the incinerator. As defined in Section
XI.B.2, periodic monitoring of the VOC contaminants of concern will
be performed to confirm attainment of EPA's on-site, risk-based
target cleanup levels. Operating conditions will be based on the
continually monitored combustion parameters which match with
acceptable VOC monitoring results.
On-site air monitoring will also be performed downwind of the
incinerator stack, within the stack plume, to assess compliance
with national secondary ambient air quality standards (NAAQS) and
State AAL's. The frequency of sampling will be the same as that
defined for VOC stack sampling in section XI.B.2. Parameters to be
included are sulfur dioxide, carbon monoxide, nitrogen dioxide, and
the target vapor phase VOC's. If this sampling demonstrates non-
compliance with the NAAQS, scrubbing or other appropriate air
treatment technologies will be promptly installed at the
incinerator so that compliance is attained.
C. Sediment remedy
Contaminated sediments in the Dunstable Brook tributary leading
from the landfill's existing western leachate pump station, and
possibly some downstream reaches of the Brook itself, will be
dredged down to about one foot in depth, transported to the site
for solidification, then placed on the uncapped landfill for
capping with the source control's high density polyethylene (HOPE)
liner. This sediment remedy requires some coordination with the cap
construction, but enough time is anticipated to allow for
implementation of this alternative before installation of the HOPE
liner. If needed, other alternatives which offer equal permanence
and protectiveness, and which meet construction fill requirements,
will be considered.
Remedial design will start with sediment sampling to determine the
present extent of PAH contamination above EPA's risk-based cleanup
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level of 1 mg/kg. Once this sampling defines the cleanup area,
construction of a small, temporary gravel road following the brook
can be completed as needed for excavation. Once the excavation
work is complete, the wetland area impacted will be restored to its
original condition. The excavation, solidification and placement
of the contaminated sediments will then proceed according to
Sections 8.1 and 8.4 of the FS. Bench-or pilot-scale tests will be
done to determine appropriate use of PAH-immobilizing additives.
XI. Rationale for selection and points of compliance
The rationale for choosing the selected alternatives is based on
the assessment of each criteria listed in section VIII of this
document. In accordance with Section 121 of CERCLA, to be
considered as a candidate for selection in the ROD, the
alternative must have been found to be protective of human health
and the environment, and able to attain ARARs unless a waiver is
warranted. In assessing the alternatives that met these threshold
statutory requirements, EPA focused on the other evaluation
criteria, including, short term effectiveness, long term
effectiveness, implementability, reduction of mobility, toxicity
and volume, and cost.
EPA also considered nontechnical factors that affect "the
implementability of a remedy, such as state and community
acceptance. Thus, the nine factors which were discussed in
section VIII, were evaluated during the decision process. Again,
these nine factors are compared for each alternative in Table 10.
Based upon this comparative analysis and taking into account the
statutory preferences of CERCLA, EPA selected the remedial
approach for the Site.
A. Groundwater and leachate
1. Rationale
Extraction and treatment of southwestern overburden is necessary
to reduce the unacceptable risks to human health and the
environment posed by this plume, as discussed in section VI, and
to comply with groundwater-quality ARAR's of SDWA and RCRA.
Southwestern shallow bedrock may also require remediation, as
described in section X.A, depending on the remedial design
monitoring results from this hydrologic unit. Extraction and
treatment of eastern overburden and shallow bedrock groundwater is
required for compliance with SDWA and RCRA MCL's. Remediation of
these eastern upper aquifers will also eliminate their
environmental threat to Flint Pond Marsh and Flint Pond.
Contaminated deep bedrock groundwater was not selected for
remediation other than continued monitoring for five reasons. The
first reason involves impracticability. Given the uncertainties in
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the spatial extent of the deep bedrock plume and the difficulty in
predicting groundvater flow in bedrock, it is considered infeasible
to extract the entire deep bedrock plume: Heavy pumping of the
eastern deep aquifer could cause further contaminant migration by
drawing contamination from the shallow aquifers into deep bedrock.
Second, upon activation of the new municipal waterline serving the
Cannongate area, scheduled for the fall of 1988, the deep aquifer
in the Cannongate area will not be used for drinking water. Third,
since the landfill is not expected to contribute more contaminants
to the deep plume, MCL's and acceptable risk levels should be
attained through natural attenuation at an approximate distance of
1000 east of the landfill/Cannongate axis. This area is comprised
mainly of highway and marsh, and is therefore undevelopable.
Fourth, this deep plume is not expected to recharge Flint Pond
Marsh, Flint Pond or the Flint Pond overburden aquifer. As such,
it will not pose environmental risks to these surface waters nor
human health risks to users of the Flint Pond overburden aquifer.
Finally, a groundwater monitoring program will be implemented to
provide early detection of contaminant increases from the deep
bedrock plume. Additional remedies will be considered, including
extensions to the new waterline, if this monitoring indicates
potential significant risks to human health from this plume.
Leachate requires treatment as defined by EPA's remedial operable
unit four for the site. Since contaminated groundwater will be
extracted for treatment, collected leachate can be combined with
groundwater for joint treatment. The biological-based treatment
alternative was selected rather than the carbon-based or air-
stripping-based alternative for treatment of the combined
groundwater and leachate because it should be more effective in
removing all the waste stream contaminants, especially acetone, 2-
butanone and benzole acid. The cost estimates for the three
combined groundwater arid leachate on-site treatment alternatives
were roughly equivalent, given the accuracy of the estimate, and
they were all significantly less costly than off-site treatment
(GW-6). As explained in section VII, final discharge to
groundwater was selected, if feasible, to comply with
Massachusetts' surface water anti-degradation requirements.
2. Points of compliance
The cleanup levels required for the protection of human health and
compliance with ARARs are listed in Table 8 for the aquifers to be
remediated. These aquifers must be extracted for treatment until
these cleanup levels are attained throughout the respective aquifer
from the upgradient landfill boundary to the extraction points. As
discussed on page 7-11 of the FS, this will result in the
attainment of SOWA and RCRA MCL's throughout these aquifers since
any downgradient contaminants not extracted will be quickly
attenuated to concentrations below respective MCL's. Sampling
throughout these aquifers will be continued through remedial design
and implementation to monitor compliance with these cleanup levels,
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and to also monitor other contaminants as listed in Table 11. Once
the cleanup levels are attained, a demonstration of consistent
attainment will be made by monthly monitoring of the Table 8
contaminants until the cleanup levels have been complied with for
twelve consecutive months. Jf during this demonstration cleanup
levels are exceeded, then extraction and treatment of the plume(s)
with exceedances will again be required. Once this consistent
attainment is demonstrated, the post-closure groundwater
monitoring as discussed in section X will be used to monitor
subsequent compliance with the cleanup levels.
The concentration levels required for groundwater discharge after
treatment are listed in Table 11. These levels shall be attained
at a representative sampling location prior to any mixing with the
diverted upgradient groundwater. If groundwater and leachate are
treated separately, both shall meet these discharge levels prior to
mixing.
The diverted upgradient groundwater shall be monitored monthly,
before mixing, for the compounds listed in Table 11 during its
first year of operation. Appropriate engineering responses will
be promptly implemented if contamination is detected. During
start up of the treatment plant, weekly monitoring of the Table 11
parameters will be required until compliance with the discharge
levels is demonstrated for four consecutive weeks. Monthly
monitoring will be required thereafter. If non-compliance is
detected, prompt and appropriate engineering responses will be
implemented, and weekly monitoring will again be required until
compliance is attained for four consecutive weeks.
B. Vent emissions
1. Rationale
The treatment of vent emissions is necessary to reduce
unacceptable on-site health risks posed by various gaseous VOC's
as discussed in section VI. Risks to human welfare as a result of
the objectionable odor, and potential off-site risks to human
health given a worst case exposure scenario were also considered
in the decision for treatment. Incineration was chosen as the
treatment technology because it has been demonstrated as the most
effective in achieving the VOC removal efficiencies required.
Also, unlike the gas flaring or gas recovery alternatives,
incineration will not generate sidestreams requiring treatment.
Incineration offers the least amount of adverse, short term
impacts, and is the most protective of the gas treatment
alternatives.
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2. Points of compliance
The cleanup levels required for vent emissions are listed in Table
8. These levels shall be attained at a representative location in
the stack. During initial start-up of the incinerator, sampling of
the VOC's listed in Table 8 will be performed until all the target
levels are attained during four consecutive sampling episodes.
Thereafter, the continually monitored parameters described in
section X.B will be used to indicate compliance with the target
levels. During steady-state operation of the incinerator, the
VOC's listed in Table 8 will be analyzed at least annually to
monitor long term compliance with the target levels. Appropriate
and prompt engineering responses will be implemented if non-
compliance is detected, and demonstration of a return to compliance
will be made.
C. Sediment
1. Rationale
Remediation of contaminated sediments in the Dunstable BrooJc
tributary from the existing western pump station, and possibly
reaches of the Brook itself, is necessary to reduce to acceptable
levels the existing incremental cancer risks above IxlO-6 for a
most probable exposure scenario. As discussed in footnote 5 of
Table 7, these risks are expected to be much higher than this in
the pump station tributary.
Solidification and on-site disposal was selected as the treatment
system because it will cost-effectively minimize PAH migration, and
it will be a cost-effective permanent remedy for the contaminated
sediments. It will also comply with construction requirements for
fill material.
2. Point of compliance
The horizontal extent to which Dunstable Brook sediments will be
dredged for treatment will be determined by remedial design
sediment sampling. Sediments in the western pump station
tributary or the Brook containing carcinogenic PAH concentrations
above 1 mg/kg will be excavated, solidified and placed on the
landfill for capping.
XII. Statutory Determinations
The phase III remedial actions selected for implementation at the
Charles George Landfill are consistent with CERCLA and, to the
extent practicable, the NCP. The selected remedies are
protective of human health and the environment, and, with the
exception of attaining SDWA MCLs in the residual eastern deep
bedrock plume, attain ARARs. The selected remedies also offer the
best combination of effectiveness, implementability, and cost in
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comparison with the other protective alternatives. The selected
remedies are consistent with section 121 of CERCLA and satisfy the
statutory preference for permanent solutions and for treatment
which reduces the mobility, toxicity or volume as a principal
element. Additionally, the selected remedies utilize permanent
solutions and innovative technology to the maximum extent
practicable.
A. The selected remedy is protective of human health and
the environment
Through collection and treatment of contaminated overburden and
shallow bedrock groundwater, leachate, gas emissions and
sediments, the phase III remedy at the Charles George Landfill
protects human health and environment against risks posed by these
media. Human health and the environment should not be jeopardized
by the residual deep bedrock groundwater plume, but any unknown
risks posed by this groundwater will be detected for further
remedial consideration through groundwater monitoring.
The Agency's risk analysis concludes that upon successful
implementation of this remedy, most probable total site risks,
excluding risks due to arsenic at or below its MCL, range from an
ICR of 1.2 x 10"5 to 8.9 x 10~6, depending on the exposure
scenario. Risks above these levels due to groundwater arsenic
concentrations at or below the MCL are considered adequately
protective because of the conservativeness and scientific
uncertainties associated with the arsenic risk level. Table 3-6
of the FS lists the multimedia risk assessment exposure scenarios
and the total site risk results. This table used 4000 feet
eastward for the exposure point of deep bedrock groundwater
because this is the distance of the closest existing deep bedrock
residential well within the projected path of the plume.
B. The selected remedy attains ARAJRs
Except for the attainment of SDWA MCL's for benzene, arsenic, and
possibly cadmium in the existing residual eastern deep bedrock
plume, this remedy will meet or attain all applicable or relevant
and appropriate federal and state requirements that apply to the
site. Environmental laws which are applicable or relevant and
appropriate to the selected remedial actions at the site include
the:
Resource Conservation and Recovery Act (RCRA)
Clean Water Act (CWA)
Safe Drinking Water Act (SDWA)
Clean Air Act (CAA)
Executive Order 11990 (Protection of Wetlands)
Table 12 and Table 13, taken from Chapter 2 of the FS, list the
chemical specific and location specific ARARs, respectively, and
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outline the action which will £& taken to attain the ARARs. Table
14 indicates the action specific ARARs, presents a brief synopsis
of the requirements, and outlines the action which will be taken to
attain the ARARs. A brief narrative summary of the ARARs follows:
As explained in Table 10 - criterion 7, extraction of the
contaminated shallow groundwater aquifers to the east and
southwest of the site will comply with RCRA corrective-action and
SDWA MCL ARARs since these aquifers will be extracted until
contaminant levels are below respective MCL's throughout these
aquifers up to the landfill boundary.
Also explained in Table 10 - criterion 7 and on pp. 30 - 31, the
monitoring-only remedy for the eastern deep bedrock plume is
expected to result in non-attainment of SDWA MCL's for about 1000
feet eastward from the plume's present location. However, due to
the site-specific factors involved - including the technical
infeasibility of extracting the entire deep bedrock plume, the
presence of municipal water supply, scientific uncertainties
associated with the risks of arsenic, and surface features above
the plume's predicted migratory path - the residual deep plume was
not selected for extraction. Since all aquifers in the area are
classified as Class I and potentially drinkable, SDWA MCL's are
considered ARARs for the deep bedrock plume as well as the other
southwestern and eastern plumes. Thus, SDWA MCL ARARs for benzene,
arsenic, and possibly cadmium are not expected to be immediately
attained within the eastern deep bedrock plume.
Groundwater modeling indicates that natural attenuation should
provide for the attainment of arsenic and cadmium MCL's before the
plume travels 500 feet eastward. Benzene concentrations, however,
could remain above the MCL for distances up to approximately 1000
feet eastward. Also, the Agency's risk analysis estimates that,
excluding the uncertain risks due to arsenic, acceptable risk
values will be attained in the deep plume before it travels 500
feet eastward.
Concerning other ARARs associated with groundwater and leachate,
the extracted groundwater and leachate will be treated until it
meets CWA discharge requirements and SDWA MCL's. Regardless of
whether the discharge is to groundwater or surface water, the
appropriate discharge requirements will be met. Also, the
ultimate disposal of treatment residuals will comply with RCRA
Subtitle C requirements for hazardous waste disposal regardless of
whether this sludge is disposed on site or off site.
Concerning the vent emission remedy, NAAQS ARARs will be attained,
as explained on p. 29, and State AAL's will be considered. The
target levels for VOC's are based on potential on-site health
risks, and in some cases are greater than the AAL's. Atmospheric
dilution should allow for attainment of AAL's in off-site
neighborhoods, however.
35
-------
The sediment remedy will comply with EO 11990 and §404 of the CWA
(40 CFR Part 230) in that the remedial design sediment sampling
will be used to limit the wetland area impacted to that required
only for the protection of human health and the environment. The
only practicable alternative to protecting human health and the
environment from the contaminated sediments is to cap the
sediments in place. This alternative has more adverse impacts
associated with it, however, including heavier losses to
terrestrial and aquatic habitats and lower benthic recolonization
potentials. The selected remedy's requirements for oil booms,
silt screens and wetland restoration also comply with the
requirements of EO 11990 and the CWA §404 for inclusion of all
practicable measures to minimize harm to wetlands.
C. The selected remedial action is cost-effective, and uses
permanent solutions and alternative treatment
technologies to the maximum extent practicable
Of those remedial alternatives that are protective and attain
ARARs, EPA selected remedial alternatives that are both cost-
effective and utilize permanent solutions to the maximum extent
practicable, based on balancing short and long term effectiveness,
implementability, reduction of toxicity, mobility and volume, and
cost. As previously discussed, it is impracticable to attain a
permanent solution, with any certainty, for deep bedrock
contamination.
Once the contaminated sediments are solidified and permanently
disposed beneath the landfill cap, successful implementation of
both the on-site biological-based groundwater and leachate
treatment plant and the fume incinerator will result in a long-
term solution to the remaining environmental problems at the site.
These two treatment systems offer the best capabilities for
attaining their respective target levels and discharge
requirements over the long-term. Given that the landfill will
remain capped where it is, these two treatment systems represent
permanent solutions to the maximum extent practicable.
The selected remedies for contaminated groundwater, leachate, vent
emissions and sediments are cost-effective in attaining
permanency. The biological-based groundwater and leachate
treatment plant is comparable in cost to the other on-site
alternatives, given the accuracy of the cost estimate, yet it
should provide more permanent attainment of discharge levels. As
compared to the off-site treatment facility, it represents the
same degree of permanency in remediating contaminated groundwater,
but its costs are significantly less. Regarding the vent emission
remedy, costs for the gas flaring or gas recovery alternatives are
estimated to be fifty-seven percent and seventy-eight percent of
the costs for incineration, respectively, yet incineration offers
significantly more permanence in attaining all the gaseous VOC
target levels. As for the sediment remedy, on-site disposal
36
-------
without treatment would cost less, but it would offer less
permanence as compared to on-site disposal with solidification.
The other sediment alternatives are all more costly while not
attaining a significantly greater degree of permanency. All the
phase III remedial design and implementation costs are presented in
Table 15.
In-site sediment capping was the principle alternative technology
carried through detailed analysis. For reasons discussed in
section IX.C, however, it was not considered adequately protective
or permanent. The gas recovery (electrical generation) vent
emission remedy was the only resource recovery technology
considered, but as previously discussed in Section IX.B, it was not
considered as effective as flaring or incineration. The selected
sediment alternative involving solidification of PAH's, however,
represents an innovative technology since bench-scale testing will
be required to determine the effectiveness of various additives at
immobilizing the PAH's within the solid sediment matrix.
D. The selected remedy satisfies the preference for
treatment as a principle element
The selected alternatives for treatment of contaminated
groundwater and leachate, incineration of vent emissions, and
solidification and disposal (capping) of contaminated sediments
all employ treatment as a principle element.
37
-------
nCDRES AND TABLES
-38-
-------
.3EORGELAND
RECLAMATION TRUST
Rojte of new waterline
FIGURE 1
SITE LOCATION MAP
-39-
-------
\<^—r
I
c
• OUHCI* SA1C M«^ PMIPAMf OfOM NU1
III MtPOMT INU1, l**«l LANDFILL
MttUNVITIO BY LANUN CMOINttMS AND
ANCHtTICTC Of MOCHISTCN.M.T. fOU 1C
JORDAN IM
1000 FIII
W-:/ ...
NOTES
I Wlllt tllOWN A* CONIAUMAIID • IOIAI VO> Alt I ONCAM
CUMCIMIHAIION I "CM IHO It *f» Al llAtl UNCI M
Itl* •! ri HN)O
I IfWI AO I AM II ON WAIID IAB1I CONIOUM MAP (IK. I • |
CAICU AIIOMAIIft Of GAM0OWAIIH I tOW. AND •* I WttD
Ol^C**A|4ut AHt Al
i trm AO»«SIO oxxiiNrm IAIKM o> MTDMAUIK UAIA
nrt tiNiin ON»Ar& wttiufnt 'It II
I IIX.IS ttt COMIAMmAIID AW At AM OMf AfTHOH XI Al 11Y
dNUWK
LEGEND
.HI
MU*fllOMV«O Will
tMAIAOW Will TttlDMG CONlAHMAIf O WAIIR'
Otl^ •IUAOCM Will VftlCMNG COMlAMNAItO WAIIH
ftlMAItQ CON1AMNANI KTf« AO AM.A M
o>
IWCONtOlOAltD UD
Ntt « tXAllOW MCMOCll
111
IIIMAIIO CONIAMMAMI •TRIAD AM A
ciixio uorocir''
FIGURE 2
ESTIMATED HISTORICAL
SPREAD OF LANDFILL
CONTAMINANTS IN GROUNDWATER
CGL SITE
-------
TABLE 1
Maximum Chemical Concentrations in Groundwater (ug/l)
Charles George Landfill - 19O7
Chemica 1
acetone
2 butanone (MCK
benzene
toluene
ethyl benzene
xylenes
4-methyl-2
pentanone
1 , l-dichloro
ethane
phenol
bonzoic acid.
4 -methyl phenol
bis (2-ethyl
hexyl )phthalatc
a luminufn
arsenic
bar ium
cadmium
chromium
cobalt
copper
i ron
lead
manganese
mercury
nickel
si 1 ver
sodium
z me
South
Western
Overburden1
'
229
710
20 J
450 J
16 J
21
110
140
»
231
249
2O0
16
50
38OOO
1 36OO
152
1 3 7OOO
130
South
Western
Shal low
bedrock^
SoO J*>
190 J
8 J
44O
Hi J
20 J
ISO
36 J
220
I
Pastern
Overburden*
4O J
14
e.
430
IH
12
433
70
it
~~»i i
t U
293OO
3H/OU
0.2
93 J
1 t*9OOO
40
[.astern
Sha 1 low
bedr ock4
5700 J
Wo
t.3 J
12
1 1C) J
4t. 7
12
tl* *
950OO
239OOO
/O
19
b 1 9OO
2
-------
TABLE 1 (continued)
Footnotes
1. Data are from monitoring wells E i E/FIT 3, E &. E/FIT4, and
MW-8A (January - .March 1987).
2. Data are from monitoring well MW-8 (May 28, 1987). Data are
not available for dissolved metals, however, since the
groundwater samples were not properly filtered.
3. Data are from monitoring wells E &. E/FIT 2, MW-5A and BF-5
(January - March 1987).
•5. Data are from monitoring wells MW-5 and JDT-3 (C) (January-
March 1987 ).
5. Data are from monitoring wells NUS/FIT1, NUS/FIT2 and JDT-3
(A i B)) (Januar.-^ - March 1987).
6".. "J" indicates the concentration value is estimated.
7. The current MCL for arsenic is 50 ug/1, the listed value is
tlie currently propose-d arsenic MCL.
-42-
-------
Table 2
Maximum Chemical Concentrations in Leachate
Charles George Landfill
1984 - 87
CHEMICAL CONCENTRATION (pi/2)
Acetoae 22,000.00
2-Butanone 21,000.00
4-Methyl-2-Pentanone 1,800.00
Toluene 700.00
Ethylbenzene 140.00
Total Xylenes 160.00
1,1,2,2-Tetrachloroethane 310.00
1,1,2-Trichloroethane 25.00
1,1-Dicbloroethane 83.00
Trichloroetheae 24.00
Trans-l,2-Dichloroethene 290.00
Vinyl Chloride 250.00
Chloroform 20.00
Metnylene Chloride 7,200.00
fienzoic Acid 38,000.00
Phenol 3,000.00
4-MethyIpfaenol 12,000.00
Heptachlor . 0.12
Aluminum 73,400.00
Antimony 496.00
Arsenic 342.00
Barium 843.00
Beryllium 153.00
Cadmium 483.00
Calcium 2,000,000.00
Chromium 242.00
Cobalt 57.00
Copper 229.00
Iron 817,000.00
Lead 110.00
Magnesium 367,000.00
Manganese 242,000.00
Mercury 2.70
Nickel 1,020.00
Potassium 342,000.00
Sodium 858,000.00
Tin 113.00
Vanadium 0.00
Zinc 2,900.00
-43-
-------
Table 3
landfill as Vent Emissions
Charles George -Landfill
1984 - B7 : ..
AVERAGE VENT
CHEMICAL CONCENTRATION
1,1-dichloroethene 6.0732
1,1,2,2-tetrachloroethane 522
methylene chloride 31.6922
vinyl chloride 26.9602
1 , 2-dichloroethane 15 ,2003
benzene 7.1103
1,1,2-trichloroethane 3793
trichloroethene 17,8872
carbon tetrachloride 26.5003
tetrachloroethene 12,1552
chloroform 9622
bromoform 5.69xl06 3
1 Highest average concentration from NUS data or REM III data for specific
vents.
Highest average concentration found in either of two NUS data sets (1984-
1985, 1986).
Highest concentration from REM III sampling of two landfill vents, 1987.
-------
Table 4
Maximum Chemical Concentrations in Residential Ambient air
Charles George Landfill
1987-88*
Hoare
Carcinogens Property
methylene chloride >5.26*
1,2-dichloroethane BOL
benzene 2.9O
chloroform 0.53
carbon tetrachloride 0.17
1,1,2,2-tetrachloro-
ethane BDL
tetrachloroethene BDL
trichloroethene BDL
Non-carci nogens
bromomethane BDL
toromoform BDL
chlorobenzene O.76
toluene 5.26
1,1,1-tnchloroethane BDL
xylenes BDL
Flint Pond
>3.30
BDL
>3.3O
1.63
1.63
4.88
4.88
BDL
BDL
0.17
2.44
>3.3
1.7
BDL
Cannongate
>2.88
>2.88
>2.88
0.43
2.16
BDL
BDL
4.9
0.29
BDL
0.53
>2.8B
1.4
2.4
(1) Data from Ebasco sampling (1987) and EPA, Region I Sampling
(1988).
(2) > indicates that the mass of the contaminant exceeded the
calibration range of the method. The true value is thus
greater than the listed value.
(3) BDL = Below Detection Limit
-45-
-------
TABLE 5
CONTAMINANT "LEVELS TOR SEDIJtENTS
FROM DUNSTABLE BROOK a
Sampling Site
Carcinogenic
PAHs (mg/kg) Arsenic (mg/kg)
Cadmiua (og/kg)
East of Dunstable Road
ECJ #24
ECJ V 8
1.54
5.30
Upstream of Outfall (background)
16.0
Includes NUS data (1984, 1985) and E.G. Jordan data (1987).
Carcinogenic PAHs include: benzo(a)pyrene, benzo(a)anthracene,
benzo(b)fluoranthene, benzo(k)£luoranthene, indeno (1,2,3-cd)
pyrene, and chrysene.
4.80
4.10
NUS #8-
NUS tf9
Dunstable Brook Outfall
NUS # 7 2.32
NUS #13 1.63
ECJ
-------
Table 6
CGL Contaminants of Concern - Phase III
Contaminant
Medium effected
2-butanone (MEK)
toluene
acetone
benzene
4-methyl 2-pentanone
ethyl benzene
1 , 1-dichloethene
trichloroethene
1 ,2-dacnloroethane
methylene chloride
chloroform
1 , 1,2,2- tetrachloroetr
vinyl chloride
tetrachloroethene
carbon tetrachlonde
1 , 1 ,2-trichloroethane
chlorobenzene
carbon disulfide
xylenes
bromome thane
bromof orm
benzoic acid
4-methyl phenol
2-methyl phenol
phenol
PAH'S
arsenic
chromium
copper
mercury
cadmium
Groundwater
and
Leachate
X
X
x
X
X
X
X
X
lane
X
X
X
X
X
X
^
X
X
Air
K— — . I— -
— — — —»—•
X
X
X
X
X
X
X
y
X
X
X
X
X
X
x
X
X
Sediment
•
h.
X
X
X
-47-
-------
TABLE 7
Summary of CGL Risk Assessment
Exposure Medium
I. Groundwater
A. Southwestern Plume
1. Overburden
2. Shallow bedrock*
B. Eastern Deep Grounc
1 . 500 ft
a. all contaminants
b. arsenic excluded
2. 1000 ft
a. all contaminants
b. arsenic excluded
3. 2000 ft
a. all contaminants
b. arsenic excluded
4. 4OOO ft
a. all contaminants
b. arsenic excluded
II. Air
A. On sight*
1. 1984-86
2. 1987
B. Off sight
1. 1987^
a. Flint Pond
b. Cannongate Pond
c. Abandoned House
2. Present Modeled RJ
a. Flint Pond
b. Cannongate
c. Abandoned House
3. Future Modeled Ri<
a. Flint Pond
b. Cannongate
c. Abandoned House
LI 1 . Sediment
m. Dunstable Brook*
^3. Flint Pond Marsh
C. Flint Pond
Individual Incremental
Cancer Risk
Most J worst
-Probable--H
1.8x10-2
6.6x10-6
3water2
6.9xlO-"
4.3x10-*
2.8x10-"
1.7X1O-*
9.4x10-*
5.2x10-6
3.7xlO-*
2. 3x10-0
5.2x10-*
3.0x10-"
1.2x10-*
4. 1x10-6
1.7xlO-6
sk"
1 . 1x10-6
5.6X10-6
5.6x10-6
5k"
2.8x10-7
1 .1x10-6
5.2xlO-7
>1 .2x10-6
1 .OxlO-8
9.9x10-9
2.2x10-2
4.6x10-"
1 .2x10-3
4.2x10-"
1 .5x10-"
6.2x10-*
>9. 2x10-6
1 .6x10-*
5.9x10-6
Hazard Index
MOSt
i-Probable-H
0.90
1.1
0.75
O.27
0.10
0.03
O.OO4
2.0
0.007
0.007
O.OO1
« 1
« 1
« 1
« 1
« 1
« 1
Worst
(•-Case
1.09
1.4
0.052
8.0
O.26
0.26
0.037
0.03
O.06
0.002
-48-
-------
IV. Biota*
V. Surface water
A. Flint Pond Marsh
B. Flint Pond
<4xlO-7
<7xlO-«
O.22
0.36
<1
. OO3
Footnotes
1. The carcinogenic risk assessment for shallow bedrock is
based solely on an estimated benzene concentration of 8 ppb
from one sampling episode.
2. Tne risk assessment for this plume is based on estimated
contaminant concentrations at varying distances east of the
site based on groundwater modeling. Risks with and without
arsenic are differentiated since the estimated arsenic
concentrations are below the arsenic riCL.
3. These on-site and off-site risks are based on actual,
monitored concentrations from NUS (1984-85) and Ebasco
(1987) sampling.
4. Present and future modeled risks were based on Ebasco's air
modeling of the existing, uncapped landfill (flux method)
and the future, capped and vented landfill (vent method),
respectively.
5. Risks due to sediment PAH's in the western pump station
tributary to Dunstable Brook are assumed to be greater than
the listed value. These listed values are for risks
downstream of the confluence of the tributary and the Brook.
Although no sediment data exist for the tributary, PAH
contamination is clearly higher here than after confluence
with the brook.
6. Biota ICR risks are qualified as maximum risks because these
risks are based on arsenic found in turtle tissue and not in
fish tissue.
-------
TABLE 8
Remediation Area
TARGET CLEANUP LEVELS
CHARLES"GEOBGE LANDFILL
Basis for Target Level Contaminant
Target Cleanup Level
Shallow Groundwater
Southwest
ARAR-based using MCI
for benzene and
arsenic .
Shallow Bedrock and ARAR-based using MCL
Overburden Ground- for benzene, arsenic,
water, East TCE, cadmium, and silver
Sediments, All Areas Risk-based using risk
level of 4xlO~6
Benzene
Arsenic
Benzene
Trichloroethene
Arsenic
Cadmium
Silver
PAHs
0.005 mg/2 (MCL for
benzene)
0.050 mg/£ (MCL for
arsenic)
0.005 n>g/£ (MCL for
benzene)
0.005 mg/£ (MCL fox TCE)
0.050 mg/£ (MCL for
arsenic)
0.010 mg/£ (MCL for
cadmium)
0.050 mg/S. (MCL for
silver)
1.0 mg/kg (based on risk
level of 4xlO~6
Emissions
Risk-based using cumulative 1,1-dichloroethene 12.7 |Jg/m3
site
risk level of 1x10 6 and
most-probable on-site
exposure scenario
1,1,2,2-tetra-
chloroethane
methylene chloride
vinyl chloride
1,2-dichloroethane
benzene
1,1,2-trichloro-
ethane
trichloroethene
carbon tetra-
chloride
tetrachloroethene
chloroform
bromoform
73.9
1,030 Mg/m3
591 Mg/m3
422 M8/m3
568 pg/m3
258
3,210
114
8,690
182 Mg/m3
3.23xl05
-50-
-------
TABLE 9
Technologies Identified and Screened in the FS
Groundwater and Leachate:
1. Groundwatar monitoring
2. Slurry walls*
3. Trench drains
4. Extraction wells
5. Metals precipitation
6. Aerobic/anaerobic1 biological treatment
7, Air/steam*-stripping
8. Uv/ozonation2
9. Reverse osmosis*
1O. Activated carbon adsorption
11. Clarificationsedimentation
12. Filtration
13. Chemical oxidation
14. Ion-exchange
15. Liquid-liquid extraction*
16. Supercritical water oxidation*
17. Off-site treatment at a KCRA facility
18. Off-site treatment at a Publicly Owned Treatment Works
(POTW)
19. Reinjection of treated wator into groundwater
20. Discharge of treated water to surface water
-51-
-------
TABLE 9 (continued)
Landfill Gas:
1. Condensation/acid-scrubbing
2. Carbon adsorption2
3. Molecular sieves2
•4. Flaring
5. Incineration
6. Combustion (electrical generation)
7. Atmospheric discharge
8. Discharge to natural gas pipeline
pediment:
.1. In-situ capping
2. Biodegradation*
3. Incineration
4. Molten glass electric reactor2
5. Thermal aeration
6. Solvent extraction1
7. Vitrification!
i Eliminated in preliminary screening in Chapter 4
2 Eliminated in Chapter 6 initial screening
-52-
-------
TABLE 10
EVALUATION OF REMEDIAL ALTERNATIVES BASED ON NINE CRITERIA
ALTERNATIVE
CRITERION 1: COST
Groundwater No-Action (GW-1)
roundwater and Leachate Alternatives
Carboa Adsorption (CV-2)
. Air-Stripping (GW-3)
. Biological Treatment (CW-5)
Off-Site Treatment (CW-6)
.odfill Gas Alternativei
Mo Action (CAS-1)
Gas Flarinc (CAS-3)
Incineration (CAS-4)
Combustion Recovery (GAS-5)
diment Alternative!
. No Action (SED-1)
. In-Situ Capping (SED-2.)
. On-Site Disposal (SED-7)
. On-Site Solidification
and Disposal (SED-3)
. On-Site Thermal Aeration
and Disposal (SED-4)
. Off-Site Solidification
and Disposal (SED-5)
. Off-Site Incineration
and Disposal (SED-6)
Estimated Capital Cost: 5151,000. Estimated Annual O&fl Cost: $113,000. Esti
Present Worth: $1,216,000.
Estimated Capital Cost: $2,995,000. Estimated Annual OM Cost: $6*6,000.
Estimated Present Worth Cost: $9,809,000.
Estimated Capital Cost: f*,«M,ooo Estimated Annual OUl Cost: I
Estimated Pretest Worth Cast: «
Estimated Capital Cast: $3,318,000. Estimated Annual OSH Cast: $394,000.
Estimated Present Worth Cost: 1$ %QQ QotO
Estimated Capital Cost: $1,161,000. Estimated Annual CAM Cost: $12,259,000.
Estimated Present Worth Cost: $117,397,000.
No immediate costs.
Estimated Capital Cost: $237,000. Estimated Annual OUl Cast: $37,000. Estimated
Present Worth Cost: $586,000.
Estimated Capital Cost: $959,000. Estimated Annual 04M Cast: $4,000. Estimated
Present Worth Cost: $1,034,000.
Estimated Capital Cost: $1,658,000. Estimated Annual O&H Cast: -$90,000. Estimated
Present Worth Cost: $809,000.
No
ediate costs.
Estimated Capital Cost: $98,300. Estimated Annual Off! Cost: $4,900. Estimated
Present Worth Cost: $144,200.
Estimated Total Cost: $40,800.
Estimated Total Cost: $79,000.
Estimated Total Cost: $915,000.
Estimated Total Cost: $208,000.
Estimated Total Cost: $1,404,700.
9.88.8?
0001.0.C
-53-
-------
TABLE 10 (cont.)
EVALUATION OF REMEDIAL ALTERNATIVES BASED ON NINE CRITERIA
.TERNATIVE
CRITERIOM 2: IMPLEMENTABILITY
l.^BPbundwater No-Action (CW-1)
Croundwater ind Leacbate Alternatives
2. Carbon Adsorption (GV-2)
3. Air-Stripping (CW-3)
4. Biological Treatment (GW-S)
•
5. Off-Site Treatment (GW-6)
Landfill Gas Alternatives
6. Mo Action (CAS-1)
7. Gas flaring (GAS-3)
B. Incineration (GAS-4)
9.
ustion Recovery (CAS-5)
Sedinent Alternatives
10. No Action (SED-1)
11. In-Situ Capping (SED-2)
12. On-Site Disposal (SED-7)
13. On-Site Solidification
and Disposal (SED-3)
14. On-Site Thermal Aeration
and Disposal (SED-4)
15. Off-Site Solidification
and Disposal (SED-5)
•
16. Off-Site Incineration
and Disposal (SED-6)
Installation and maintenance of new groundwater monitoring wells required.
easily and quickly implemented.
Could be
Treatment equipment is well proven and reliable. Lawful sludge disposal would be
required. Constable Brook discharge could be implemented sore easily than a
Merrimack River discharge since the latter would require easements for wetlands,
highways, and a railroad. Further investigation needed for groundwater discharge.
Approximately 2 1/2 years required for design and construction.
Same implementability concents as for GW-2.
Same impleaentability concerns as for GV-2. Also, approximately 151 lore sludge by
weight would require disposal. Bench- or pilot-scale testing recommended to assess
potential for nicrobial toxicity problems. Would require careful operation since
the biological system may be sensitive to changes in influent quantity and quality.
Discharge to a POTW could not presently be implemented (see Table 7-21 in PS).
Discharge to a RCRA facility considered feasible but would require long-term
contracts and would be dependent on compliance of the RCRA facility.
Not applicable.
Technically feasible; easily implemented. 13 months for design and construction.
Technically feasible; easily implemented. 16 months neces-sary for design and
construction.
Technically feasible. Coordination with the landfill cap construction project for
the drilling of the deep gas wells could push the design and construction time for
this alternative beyond the estimated 17 months otherwise required. Contract with
local utility required.
Not. applicable.
Technically feasible. Construction would take approximately six months.
Technically feasible. Coordination with landfill cap construction project required.
Three to six months necessary for total operation.
Technically feasible. Coordination with the landfill cap construction project and
testing of additives required. Three to six months necessary for total operation.
Technically feasible; thermal aeration equipment is available. Coordination with
the landfill cap construction project required. Moisture content of the sediments
could cause performance or operating problems. Three to six months necessary for
total operation.
Technically feasible. No coordination with cap construction required. Six months
necessary for total operation.
Technically feasible. Incinerator availability could be a problem. No coordination
with cap construction required. 3-6 months necessary for total operation.
9.88.87
0002.0.0
-54-
-------
TABLE 10 (cont.)
EVALUATION OF REMEDIAL ALTERNATIVES .BASED ON NINE CRITERIA
ALTERNATIVE
CRITERION 3: OVERALL PROTECTION OF HUNAN HEALTH AND THE EHVIROHMEMT
1. Croundwater No-Action (CW-l)
Croundwater and Leachate Alternatives
2. Carbon Adsorption (GW-2)
3. Air-Stripping (CW-3)
4. Biological Treatment (GW-5)
5. Off-Site Treatment (GW-6)
Landfill Gas Alternatives
6. No Action (CAS-1)
7. Gas flaring (GAS-3)
B. Incineration (CAS-4)
9. Combustion Recovery (GAS-5)
Sediment Alternatives
10. No Action (SED-1)
11. In-Situ Capping (SED-2)
12. On-Site Disposal (SED-7)
13. On-Site Solidification
and Disposal (SED-3)
\99X, and 901, respectively. Based on these rates,
this alternative may not attain clean-up levels.
More protective than all other landfill gas alternatives. Target clean-up levels
would be achieved if designed and operated properly.
Least protective of the three gas treatment alternatives, but more protective than
the no-action alternative.
Unprotective. Risks posed by sediment contaminants would not be eliminated, reduced
or controlled.
Since contaminated sediments in Dunstable Brook would be contained only, sedi
clean-up levels would not be attained. This alternative would not present
appreciable human health risks, but it does not adequately protect the environment.
Benchic recolonization potential would be the lowest for this alternative than for
Alternatives SED-3 - SED-7.
As with all the renaming alternatives involving excavation, some temporary
destructive environmental effects would occur. Contaminants would be removed,
however, and the area would be restored to its original state. Thus this alternative
and the remaining alternatives offer overall protection to the environment. Human
health would also be adequately protected.
Adequate protection of human health and the environment.
Adequate protection of human health and the environment.
Adequate protection of human health and the environment.
Adequate protection of human health and the environment.
9.88.87
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TABLE 10 (cont.)
EVALUATION OF REMEDIAL ALTERNATIVES BASED ON NINE CRITERIA
ALTERNATIVE
CRITERION A: SHORT-TERM EFFECTIVENESS
1. ^dwater No-Action (GW-1)
Croundwater and LeachiCe Alternatives
2.' Carbon Adsorption (CW-2)
3. Air-Stripping (GW-3)
i.« Biological Treatment (CW-S)
5. Off-Site Treatment (CW-6)
•
Landfill Gas Alternatives
6. No Action (CAS-1)
7. Gas Flaring (GAS-3)
3. Incineration (GAS-A)
9. Combustion Recovery (CAS-S)
Pediment Alternatives
•
10. Rtion (SED-1)
11. In-Situ Capping (SID-2)
12. On-Site Disposal (SED-7)
13. On-Site Solidification
and Disposal (SED-3)
1A. On-Site Thermal Aeration
and Disposal (SED-A)
IS. Off-Site Solidification
and Disposal (SED-S)
16. Off-Site Incineration
and Disposal (SED-6)
Not applicable.
All three on-site groundwater and leachate treatment alternatives (GW-3, GW-4, and
GW-S) are equally effective in the short-tern since all would take about 2 1/2 years
to design and construct.
Equivalent to GW-3 la start up requirements. Air emissions would be generated
throughout implementation.
Equivalent to CW-3 in start-up requirements.
Could be implemented saoaer than the on-site alternative assuming administrative
problems with a RCRA-coopliant facility would be overcome.
Not applicable.
Could be implemented somewhat faster than GAS-A and GAS-5 (13 months verses 16 and
17 months, respectively). Secondary pollutants would be created by the combustion
process in all three treatment alternatives.
Could be implemented sooner than gas recovery, but would take longer to implement
than flaring.
Of the three gaa treatment alternatives, this would take th» longest to implement.
Construction of the deep gas wells would release gaseous contaminants causing adverse
impacts to human health and the environment.
Not applicable.
All remaining sediment alternatives would have temporary negative environmental
impacts due to construction of a temporary access road. The area would be restored,
however.
Temporary access road required.
Temporary access road required.
Temporary access road required. Vapor-phase PAHs would need treatment before
discharge.
Temporary access road required.
Temporary access road required.
9.88.87
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TABLE 10 (coat.)
EVALUATION OF REMEDIAL ALTERNATIVES BASED ON NINE CRITERIA
ALTERNATIVE
1. Croundwater No-Action (GW-1)
Crouadw«ter and Leachate Alternatives
2. Carbon Adsorption (CW-2)
3. Air-Stripping (GW-3)
4. Biological Treatment (GW-S)
5. Off-Site Treatment (CVI-6)
Landfill Gas Alternatives
6. No Action (CAS-1)
7. CM flaring (GAS-3)
6. Incineration (GAS-*)
9. Combustion Recovery (CAS-5)
Sediment Alternatives
10. No Action (SED-1)
11. In-Situ Capping (SEO-2)
12. On-Site Disposal (SED-7)
13. On-Site Solidification
and Disposal (SED-3)
14. On-Site Thermal Aeration
and Disposal (SED-4)
IS. Off-Site Solidification
and Disposal (SED-S)
16. Off-Site Incineration
and Disposal (SED-6)
CRITERION 5: LONG-TERM EFFECTIVENESS AND PERMANENCE
Would not maintain reliable protection of human health and the environment.
Of the three on-site groundwater and leachate alternatives which offer overall
protection to human health and the environment, CW-2 should be most prone to
reliability problems since carbon adsorption is the only treatment unit in this
alternative able to remove organic contaminants. Carbon adsorption has not been
proven effective in removing acetone, 2-butanone and benzoic acid.
Should offer more reliability than CW-2 since both air-stripping and carbon
adsorption units could remove organic contaminants. Could be less reliable than
CW-5, though, since 2-butanone, acetone, and benzoic acid may not be effectively
removed.
CW-5 offers the best long-term effectiveness at removing site contaminants,
especially 2-butanone, acetone, and benzoic acid. This alternative would require
careful operation since the biological system may be sensitive to changes in influent
quality and quantity.
CW-6 could pose reliability problems in the long-term if off-site facilities became
unable to accept site «aste because of compliance or capacity problems.
Not applicable.
Aqueous side streams would be generated throughout implementation of this
alternative. May not reliably attain cleanup goals for vapor-phase VOCs.
CAS-4 would be the most effective of the three gas treatment alternatives ia tae
long-term. No side streams would be generated, and all gaseous target levels should
be attained.
CAS-S is considered the least effective of the three gas treatment alternatives.^mVC
removal efficiencies are less and corrosion related down time is more frequent for
this alternative's technology than for those of CAS-3 and CAS-4. Target levels may
not be attained.
Not applicable.
SED-2 offers the least permanence and long-term effectiveness of the remaining
sediment alternatives. The sediment cap would require on-going maintenance and
possibly replacement.
Since the remaining sediment alternatives involve dredging and some form of treatment
and/or disposal. They are all roughly equivalent in long-term effectiveness and
permanence. The varying degrees of treatment do offer minor differences in
permanence, though.
Offers somewhat more permanence than SED-7 since the sediments would be solidified
before capping.
Could provide more permanence than both SED-7 and SED-3 since thermal aeration
could be more effective in removing PAh's thin solidification is in containing
PAH's.
Equivalent to SED-3 in permanence.
Incineration is well demonstrated for PAH removal, thus SED-6 offers the best
permanence.
9.88.87
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TABLE 10 (cent.)
EVALUATION OF REMEDIAL ALTERNATIVES BASED ON NINE CRITERIA
. ALTERNATIVE
ll^^pbundvater No-Action (CW-1)
Groundwater lod Leachate Alternatives
2. Carbon Adsorption (GW-2)
3. Air-Stripping (CW-3)
4. Biological Treatment (GV-5)
•5. Off-Site Treatment (CW-6)
landfill Gas Alternatives
.6. No Action (CAS-1)
7. Ca* Flaring (CAS-3)
8. Incineration (CAS-4)
9. Combustion Recovery (CAS-5)
Sediment Alternatives
ID. Ho Action (SID-})
11. la-Sitii Capping (SID-2)
12. Qn-Site Disposal (SED-7)
'Site Solidification
ii Disposal uLb-3)
14. On-Site Thermal Aeration
and Disposal (SED-4)
15. Off-Site Solidification
and Disposal (SED-5)
16. Off-Site Incineration
and Disposal (SED-6)
CRITERION 6: HEDUCTIOM OF TOXICITY. MOBILITY OR VOLUME
No reduction in tozactty, mobility or volume.
Toxicity and mobility of aqueous contaminants would be significantly reduced since
groundwater would be extracted and treated aloag with leachate.
Toxicity and nobility would be significantly reduced.
Toxicity and mobility would be significantly reduced.
Toxicity and nobility would be significantly reduced.
No reduction in toxicity, mobility or volume of gaseous contaminant*.
Would reduce toxicity of gaseous contaminants by open flaring.
Would offer tbe most reduction of gas toxicity by incineration.
Of tbe tbree gas treatment alternatives, CAS-5 should offer the least reduction in
landfill gas toxicity.
No reduction in PAH toxicity, mobility or volume.
Capping would reduce the mobility of sediment PAHs.
On-site disposal and capping would remove PAH mobility more than SED-2 since »>»•
sediments would be prevented from contacting groundwater.
On-site solidification and disposal could remove PAH mobility more than SED-7
since additives may immobilize the PAHs within the solid matrix.
Since on-site thermal aeration and disposal would remove PAHs from the sediments and
reduce any remaining contaminant mobility via capping, SLD-A offers more reduction
in contaminant mobility than SEC-3.
Similar advantages as with SED-4.
Off-site incineration would offer the most reduction in PAH toxicity.
9.88.87
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TABU 10 (cent.)
EVALUATION OF REMEDIAL ALTERNATIVES BASED ON NINE CRITERIA
ALTERNATIVE
1. Grouadwater No-Action (CW-J)
,roundwater and Leachate Alternatives
:. Carbon Adsorption (CW-2)
. Air-Stripping (CW-3)
Biological Treatment (GW-5)
Off-Site Treatment (CW-6)
jndfill GJI Alternative*
No Action (CAS-1)
CRITERION 7: COMPLIANCE WITH ARARS
*™"^™^«^»»«™«"«^m»«»»*»«l»««™^m»™»«*m»»«m»m»«B»™^»»™lll«»«^mB»I^Bl«
Since groundwater ia the southwestern are* of the site will potentially be
drinking water, MCLs established under the SDWA are relevant aad appropriate
requirement*. Siace MCLs for benzene and arsenic nave been exceeded aad are
expected to continue to be exceeded in this area, no-action would not comply with
the SOWA nCL ARARs. BCRA groundwater corrective action ARARs would also be
unattained.
Overburden aad shallow bedrock groundwster to the east of the site is less likely
than southwestern site groundwater to be used for drinking water since these eastern
aquifers dlscharge primarily to Float Poad (Ursh (see Section V.A..2). FuCure Large
yield pumping of these upper aquifers in the area could potentially draw
contaminants froai these aquifers, however. Thus, SOWA HCL* are also relevant aad
appropriate for these aquifers. Arsenic, csdsu.ua, silver, sad beazeae
concentrations have been detected in 1987 at levels above tbeir respective SDWA
nCLs, although the magnitude of excecdances is not as significant as ia the
southwestern overburden. Arsenic, cadmium, and silver BCLs established under USA
for maximum permissible levels at the downgradient property boundary were also
exceeded in 19B7. The Landfill could potentially release further contamination to
these aquifers. Thus, if contaminant concentrations remain above HCL levels ia the
future, no-action in the eastern shallow aquifers would not attain SDWA MCL ARARs or
RCRA corrective action ARARs (40 CFR §264.92-100).
The monitoring only remedy for the Eastern Deep Bedrock Plum* is expected to result
in non-attainment of SDWA MCLs for about 1000 feet eastward from the plume's
present location. However, due to the site-specific factors involved - including
the technical infeasibility of extracting the entire deep bedrock plume, the
presence of municipal water supply, scientific uncertainties associated with the
risks of arsenic, and surface features above the plume's predicted migratory path -
the residual deep plume was not selected for extraction. Siace all the aquifers ia
the area are classified as Class I and potentially drinkable, SDWA MCLs are
considered ARARs for the deep bedrock plume. Thus, SDWA MCL ARARs for beazeae,
arsenic, and possibly cadmium are not expected to be immediately attained wit
eastern deep bedrock pit
CW-2, CW-3, and GW-5 all comply with RCRA and SDWA MCL ARAR's for groundwster
quality. The treated discharge will comply with Massachusetts' groundwater
discharge standards, or alternatively, its surface water discharge standards aad
Clean Water Act NPDES standards if groundwater discharge is infeasible. Sludge will
be disposed in accordance with RCRA Subtitle C.
See comments for CW-2. Also, vapor-phase VOCs from the air-stripping unit could
conceivably be tied-into the landfill gas treatment system, thereby meeting federal
and state air discharge requirements.
See comment for GW-2 above.
The off-site facility would have to comply with RCRA requirements to be eligible.
Requirements to be considered included in Massachusetts' Allowable Ambient Levels
(AALs) would not be attained if gas emissions were to be unmitigated.
9.88.87
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TABLE 10 (coot.)
EVALUATION OF REMEDIAL ALTERNATIVES BASED ON NINE CRITERIA
ALTERNATIVE
CRITERION 7: COMPLIANCE WITH ARARS
Gas Flaring (CAS-3)
a. Incineration (GAS-4)
9. Combustion Recovery (CAS-5)
Sediment Alternatives
10. No Action (SED-1)
11. In-Situ Capping (SED-2)
12. Qn-Site Disposal (SED-7)
13. On-Site Solidification
Add Diipos.il (SED-3)
14. Qa-Site Thermal Aeration
and Disposal (SED-4)
IS. Off-Site Solidification
and Disposal (SED-5)
16. Off-Site Incineration
Disposal (SED-6)
Should attain AALs off-site. National Ambient Air Quality Standard! (NAAQS) will t
attained. Scrubbing technology will be installed to do so if monitoring desMUStrat
non-compliance with aUAQS (especially sulfur dioxide).
See comment for CAS-3 above.
See coaaeat for CAS-3 above.
Nat applicable.
Would not comply with Section 404 of the. Clean Water Act since other alternatives
are available which have less negative impact on aquatic and terrestrial
In accordance with the Clean Water Act, the remaining sediatent alternatives were
developed which have less impacts on wetland habitats. Land Ban requirements for
PAHs are not yet in effect. SED-7 may not comply with construction requirements foi
characteristics to be used in the capping project.
SED-3 would conform to fill requirements acceptable for use in
capping project.
Pollution control devices should allow attainment of federal and state air discharge
regulations. SED-4 would not involve solidification and therefore may not comply
with construction requirements.
ARARs would be complied with assuming the off-site facility(ies) used are in
compliance with RCRA.
See comment for SED-5.
9.86.87
0008.0.0
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TABU 10 (coat.)
EVALUIZIQN OF «£0EDIAL ALTERNATIVES BASED ON HUE CSITFBU
ALTERNATIVE
CRITERION 8: STATE ACCEPTANCE
1. Gcoundwater No-Action (GW-1)
Croundwater and Leachate Alternatives
2. Carbon Adsorption (GW-2)
3. Air-Stripping (GW-3)
4. Biological Txeatmeat (GW-S)
S. Off-Site Trcjtacox («*•«)
landfill Cas Alternatives
6. Mo Action (GAS-1)
7. CM flariat (GAS-3)
B. Incineration (CAS-A)
9. Combustion Recovery (CAS-5)
Sediment Alternatives
10. No Action (SED-1)
11. la-Situ Capping (SED-2)
12. On-Site Disposal (S£D-7)
13. Oo-Site Solidification
•ad Disposal (SED-3
K. On-Site Thermal Aeration
and Disposal (SED-4)
15. Off-Site Solidification
and Disposal (SED-5)
16. Off-Site Incineration
and Disposal (SED-6)
Ac DEQE would not concur with grou&duater "oo-action" because of risks to
above Coapomiealtn standards.
Tbe DEQE will base concurrence with specific on-site treatment tecnnolo|ies 00 tot
results of bench- or pilot-scale testing of representative (roundwatcr and leadiate
ttmplet. State water quality anta-dejradaiion regulation* require al£«zaative
discharge other than iato Dunstable Brook, if feasible.
Sec co
at for GW-2 above.
See coanent for CW-2 above.
Tbe Q£Q£ would not concur witi Bt~6 based on cost-eifccxiveacsa.
Unacceptable health risks would prevent the UEQE fro* cancurrinf wita "ao-action"
for veoz
Suie would accept tbls alternative.
State would accept this alternative.
•
State would not accept Ibis alternative because huau health vay not be protected
liven the lower VOC removal efficiencies associated with Lhis .aJuuaative'a
technoloiy.
State concurrence
upcoauni restedial
State concurrence
upcoming reswdial
State concurrence
upcoauog reaiedial
Stale concurrence
upcoming remedial
State concurrence
upcoauog remedial
State concurrence
upcoming remedial
State concurrence
upcoming remedial
on all sediment remedies will
design PAH sampling.
on all sediment remedies will
design PAH sampling.
on all sediment remedies will
design PAH sampling.
on all sediment remedies will
design PAH sampling.
on all sediment remedies will
design PAH sampling.
on all sediment remedies will
design PAH sampling.
on all sediment remedies will
design PAH sampling.
be dependent on the results of
be dependent on the results of
be dependent on the results of the
be dependent on the results of the
be dependent on the results of the
be dependent on the results of the
be dependent on the results of the
9.88.87
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TABLE 10 (coot.)
EVALUATION OF REMEDIAL ALTERNATIVES BASED ON NINE CRITERIA
ALTERNATIVE
CRITERION 9: COHHCHITY ACCEPTANCE
iroundwater No-Action (GW-1)
Croundwater nod Leacbate Alternatives
2. Carbon Adsorption (GW-2)
3. Air-Stripping (GW-3)
4. Biological Treataent (GV-5)
5. Off-Site Treatment. (CV-6)
Landfill Gas Alternatives
6 Actioa (CAS-1)
7. Gas Flaring (CAS-3)
8. Incineration (GAS-4)
9. Combustion Recovery (GAS-S)
Sediment Alternatives
10. No Action (SED-1)
11. In-Situ Capping (SED-2)
12. On-Site Disposal (SED-7)
A remedy without ray groundwater clean-up would not be accepted by the local
community because the threat at c""****•*«* irtn to residential drinking wells would
remain unmitigated. Comments received during the comment period and questions asked
at the public eeeting and hearing; however, indicate community acceptance of the
"monitorug only" reaedy selected for deep bedrock groundwater. This acceptance is
obviously contingent on implementation of the shallow aquifer remedies. There is
also remaining local concern about the need for institution control of deep aquifer
use by future development.
No negative public cements were received concerning this alternative. The community
accepts discharge to Dunstable Brook provided that target levels are attained. The
community does not accept on*site disposal of hydroxide precipitation treatment
residuals, although the RCRA Subtitle C minimum technology requirements for secure
disposal may not be thoroughly understood. Cooaunity acceptance n^gh* be
attained if these reouiremenu were clearly articulated.
Same as GU-2 above.
Community acceptance for this alternative is somewhat lest than for GW-2 and GW-3
above since biological treatment would generate approximately 15 percent*more sludge
by weight in addition to the metal hydroxide sludge.
No comments were received oa this alternative. The local community vould presumable
accept off-site treatment and disposal, but it might not accept the increased truck
traffic throughout the remedial action that would result. The community would
definitely not accept temporary shut downs of the groundwater extraction systems if
the disposal to the off-site facility were to be prohibited, due to facility
non-compliance, during the remedial action.
The local coae-.unit ies ac'l Pnu'.f- 3 commuters would not accept this alternative because
tLe associated ou- and oti-nte risks and objectionable nuisance odors would remain
unmitigated.
Community acceptance would be less for this alternative than for the selected
incineration alternative because of the lower estimated VOC removal rates.
Comments from and discussions with the local community indicate their acceptance
with this alternative. Local concerns remain, however, about the need for scrubbers
and correct operating temperatures.
The local community would be opposed to the increased air emissions generated by the
deep gas well drilling required in this alternative. It would also be opposed to
the lower estimated VOC removal rates for gas recovery as compared to incineration
and flaring.
The local community most likely would not accept this alternative because of the
potential for future releases of contaminants to surface water or groundwater.
Community acceptance would be less for this alternative than with the excavation
alternatives because as a containment option it does not completely remove
contaminants from the area and it is projected to be effective for thirty years
only. The destruction of aquatic habitat would also be opposed.
Some opposition exists against on-site disposal. Non-acceptance would be greater
for this alternative than for the following two on-site disposal and treatment
alternatives (SED-3 and SED-*.).
9.88.87
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TABLE 10 (coat.)
EVALUATION OF RHEDItt ALTERNATIVES BASED OH HIKE CRITERIA
ALTERNATIVE
CRITERION 9: COMMUKITY ACCEPTANCE
13. On-Site Solidification
and Disposal (SED-3)
14. On-Site Thermal Aeration
•ad Disposal (SED-4)
IS. Off-Site Solidificatioo
ad Disposal (SED-5)
16. Off-Site Incineratioa
(SED-6)
Soaw opposition exist* against oa-aitc disposal. Oppositioa would bo IMS
alternative compared to SED-7 above, however. Oppositioa could also b« less foT tali
than tor SED-4 below since SED-4 would produce treated air csuaaioos.
Soae opposition e»ista against oo-ait* disposal. Oppositioa would be less for this
alternative coapared to SED-7 abov« since treatawnt would be involved, but oppositio
•ight be hichec far tais than for SED-3 above since so«e treated air Missions would
be generated.
CoMimity acceptance would be oiga for this alternative.
rnnaimity acceptance wo*ild be high for this alternative.
9.88.87
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TABLE 11
Groundwater Discharge Levals
Contaminant
acetone
2-butanone
tricnioroethene
benzene
toluene
ethlytoenzene
xylenes
bis (2-ethyl hexyl) phthalate
4-methyl-2-pentanone
benzic acid
4-methylphenol
arsenic
cadmium
chromium
nganese
mercury
nickel
silver
sodium
zinc
Other parameters
PH
effluent flow
biochemical oxygen demand
total suspended solids
Discharge ConcentrationCug/1)
250
60
5
5
2000
680
440
15
(monitor only)
(monitor only)
(monitor only)
50
10
50
300
50
SO
2
150
50
20
(monitor only)
6.5 -8.0 s.u.
(monitor only -gpd)
(monitor only - mg/1
(monitor only - mg/1)
-64-
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POTENTIAL CHEMICAL-SPECIFIC ARARS
1TERIA, ADVISORIES, AND GUIDANCE
ICOIA
REQUIREMENT
STATUS
REQUIREMENT SYHOPSIS
CONSIDERATION ?H THE RI/FS
Croundwater
Federal Regulatory
Requirement*
SDWA • Maximum Contaminant
Level! (MCL*) (40 CIH
141.11 - 141.16)
RCRA - Maximum Contaminant
Limit* - (40 CFH 264.94)
RCRA - Subpart F Ground-
water Protection Standard!
Alternative Concentration
Levela (ACLa)
Relevant and MCL* have been promulgated for a number
Appropriate of common organic and inorganic con-
taminants. Tbeae levcla regulate tbe
concentration of contaminanta in public
drinking water auppliea, but may alao be
considered relevant and appropriate for
groundwater aquifer* uaed for drinking
water.
Relevant and Staodarda for 14 toxic compounds bave
Appropriate been adopted aa part of RCRA groundwater
protection (tandarda. Tbeae limits are
act at MCL*.
Relevant and ACLa are one of three possible standards
Appropriate (aside from MCLs and background concen-
trations) available under Subpart F for
setting • clean-up level for remediating
groundwater contamination from a RCRA
facility.
When risks to public bealtb due to consumption
of grouodwater were assessed, concentrations of
contaminanta of concern, including benzene and TCE,
were compared to tbeir HCLa. Projected concen-
trations of benzene exceeded the HCL in several
locations. SDWA MCL's also were used in setting
discharge requirement*.
Groundwater contaminant levels were compared to
tbeae limits. Although eastern shallow groundwater
ia not a potential drinking water source, it does
exceed these limits. Therefore, it requires re-
mediation.
ACLs may be relevant and appropriate if certain
condition* relating to transport and exposure are
met. ACLs may need to be determined by EPA.
Procedures for developing ACLs are outlined in
RCRA Subpart F, Section 264.94.
u-i
vO
Slate Regulatory
Requirements
Standards (3U CMR 6.00)
DEQE - Massachusetts
Cronndwaler Quality
Federal Criteria,
Advisories, and
Guidance
DEQE - Drinking Water
Requirement* (310 CMR 22.00)
SDWA - Maximum Contaminant
Level Goal* (HCLCa)
Health Advisorie* (EPA
Office of Drinking Water)
EPA Rick Reference Dove*
(RfDs)
Applicable
Relevant and
Appropriate
To Be
Considered
To Be
Considered
To Be
Considered
Massachusetts Croundwater Quality Standards
have been promulgated for a number of
contaminants. When slate levels are
more stringent than federal level*, tbe
state levels will be used.
MCLCs are bealth-based criteria that are
to be considered for drinking water
•ource* a* a reault of SARA. Tbeae goals
are available for a number of organic and
inorganic contaminants.
Health Advisories are estimates of risk
due to consumption of contaminated
drinking water; they consider non-
carcinogenic effects only.
RfDs are dose level* developed by
EPA for poncarcinogenic effect*.
DEQE Groundwaler Standard* were considered when
determining diacbarge levels.
Requirements were considered; however, standards
do not apply to contaminants found in CGLRT
grouodwater.
Projected groundwater concentrations of copper,
trans-l,2-dichloroethene, toluene, benzene, and TCH
were compared to their MCLGs. For benzene and TCE,
MCLCs are set at zero.
Health advisories were considered for contaminants
In groundwater that may be uaed for drinking water.
EPA RfDs were used to characterize riak* due to
exposure to contaminanta in groundwater, aa well
aa other media. They were conaidered for
noncarcinogens including toluene, 2-butanone.
a-dibutylpbtbalate, acetone, mercury, and
thallium.
6.BB.1U
0107 00
-------
TABLE 12 (Continued)
POTENTIAL CHEMICAL-SPECIFIC ARARfi AND CRITERIA, ADVISORIES, AND GUIDANCE
CCL
MEDIA
REQUIREMENT
BTATU3
REQUIREMENT SYNOPSIS
CONSIDERATION IN THE Rl/FS
Massachusetts
Criteria, Advisories,
•ad Guidance
EPA Carcinogen Assessment
Group Potency Factor*
Acceptable Intake - Cbroplc
(AIC) and Subcbroolc (A1S)
- EPA Health Assessment
Documents
EPA Office of Water
Guidance - Water-related
Fate of 129 Priority
Pollution (1979) .
Massachusetts Drinkip| Water
Health Advl»oriei
Discharge to Publicly Owned Treatment Worki
Federal Regulatory
Requirements
RCRA - Pretreatmeot
Standard* («0 CFR 403) -
GLSD POTW Approved
Prelreat»ent Program
Requirement!.
To Be potency factor! are developed by EPA
Considered fro* Health Effect! Assessments or
evaluation by tbe Carcinogenic Assessment
Croup.
To Be AIC aod AIS valuea are developed from RfDa
Considered and HEAa for noncarcioogenic compounds.
To Be This guidance Manual givea traoaport and
Considered fate infoniation for 129 priority
pollutanta.
To Be DEQE Health Advisories are guidance
Contidered criteria for drinking water.
Applicable Discharges to a POTW aiuit comply with tbe
POTW'a EPA-approved pretreatment
requirements.
EPA Carcinogenic Potency Factors were used to
compute tbe individual incremental cancer risk
reaultlng from exposure to benzene, arsenic, PAHs,
tricbloroetbene, and 1,1-dicbloroetbene.
AIC and AIS values were used to characterize tbe
risks due to several honcarcinogeoi in various
•edia. These noncarclnogena include cadmium,
chromium, copper, and lead.
The manual was used to aasess tbe transport and
fate of a variety of contaminants.
DEQE Health Advisories were used to develop
discharge levels for surface water and
groundwater .
vO
vO
I
POTWs in the area with approved pret reatment
programs are being identified and the discharge
must be treated to those levels required by the
program.
Discharge to Surface WaEer/Hcrrlajack ftjy>r
Slate Regulatory
Requirements
DEQE - Massachusetts
Surface Water Quality
Standards (310 CNR 4.00)
Applicable DEQE Surface Water Quality Standards
•re given for dissolved orygen,
temperature increase, pH, aod total
coliform and there is a narrative
requirement for toxicants in toxic
amounts. In tbe abaence of a numeric
state standard for a compound, federal
AWQC would be appropriate.
Requirements were considered; however, no numerical
standards exist for contaminants found in CCLRT
groundwater which would be discharged to surface
water. Federal AWQC will be used in the absence of
nsrrative standards.
6.88.IH
0108.0 C
-------
POTEHTJAi CHEMICAI-BPECIFIC
(Continued)
AMP CRITERIA, ADVISORIES, AMD GUIDANCE
COL
MEDIA
STATUS
REQUIREMENT SYNOPSIS
CONSIDERATION IN THE Rl/FS
Federal Criteria,
Advisories, and
Guidance
Federal Ambient Water
Quality Criteria (AVQC)
Applicable
Air
Federal Regulatory
Requirea>eota
Stale Regulatory
Requirements
Federal Criteria,
Advisories, and
Guidance
Hassachuaetts
Criteria, Advisories,
and Guidance
CAA • National Ambient Air
Quality Standards (NAAQS) •
40 CFR 4,0.
DEQE - Air Quality, Air
Pollution (310 CMH 6.00 -
8.00).
Threshold U»it Values
(TLVa.)
Hastachusetts Guidance on
Acceptable Aaibienl Air
Levels (AALs)
Relevant and
Appropriate
Relevant and
Appropriate
To Be
Considered
To Re
Considered
Federal AWQC are health-based and
environmentally based criteria
which have been developed for 95
carcinogenic and noncarcinogenic
compounds.
These standards were primarily developed
to regulate stack and automobile emissions.
These standards were primarily developed
to regulate stack and automobile emissions.
These standards were issued as consensus
standards (or controlling air quality
in workplace environments.
These are guidelines in discharge permit
writing.
AWQC were considered in characterizing public
health risks to aquatic organisms due to
contaminant concentrations in surface water at
Flint Pond. Because this water is not used as a
drinking water source, the criteria developed
for aquatic organism protection and ingest ion of
contaminant aquatic organisms were considered.
AWQC were also used for setting limits for
discharge to the Nerrimack River.
Standards for sulfur dioxide, carbon monoxide and
nitrogen dioxide will be complied with.
TLVs could be used for assessing site inhalation
risks for soil removal operations.
AALs were considered when assessing the
significance of monitored and modeled residential
contamination.
6.88.114
0109.0.0
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TABU: 13
POTENTIAL LOCATION-SPECIFIC ARARS AND CRITERIA, ADVISORIES. AND GUIDANCE
CCL
SITE FEATURE
REQUIREMENT
STATUS
REqUlRErtEKT SYNOPSIS
CONSIDERATION IN THE Rl/FS
Wetland,*
Federal Regulatory
Requirement!
State Regulatory
Requirement*
Clean Water Act (CVA)
40 CFR P«rl 330
Fiib and Wild)if*
Coordination Act (16 U.6.C
661)
DEQE - Vetland* Protection
(310 CUR 10.00)
Haiardoui Waste Facility
Siting Regulations (990
CMS 1.00)
Federal Nonregulalory
Requirement* to be
Considered
Wetland* Executive Order
(EO 11990)
Applicable Under this requirement, no activity tbat
adversely affecli a wetlandt abill be
permitted if a practicable alteroative
tbat bat leaa effect ia available.
Applicable Tbi* regulation requires that any federal
agency proposing to modify a body of
vater siust consult with the U.S. Fith and
Wildlife Service*. Tbis requireateot i*
addressed under CVA Section 404
requirecent*.
Applicable Tbece regulation* are promulgated under
Wetlands Protection Laws, which regulate
dredging, filling, altering, or polluting
inland wetland*. Work within 100 feet of
a wetland i* regulated under this
requirement. The requirement also define*
wetlands based on vegetation type and
requires tbat effects on wetlaoda be
mitigated.
Relevant and Thete regulations outline tbe criteria for
Appropriate the construction, operation, and eeinteo-
•nce of a new facility or increase in
an existing facility for the storage,
treatment, or disposal of hazardous waste.
Specifically, no portion of the aite may
be located witbin a wetland or bordering a
vegetated wetland.
TO Be Under this regulation, federal agencies
Considered are required to minimize the destruction,
loss, or degradation of wetlands, and
preserve and enhance natural and
beneficial values of wetlaoda.
During the identification, screening, and
evaluation of alternatives, tbe effecta on
wetlanda are evaluated.
Requirement addressed under CVA Section 404.
If alternatives require thst work be completed
within 100 feet of a DEQE-defioed wetland, these
regulations will be considered. Mitigation of
impacts on wetland* will be addressed under
CWA 404.
These regulstions will be addressed during
the design phase of tbe treataent facility
construction.
oo
Many of the requirements of this EO will be
addressed under CWA Section 404. Any renaining
requirements will alao be considered during
tbe identification, screening, and evaluation
of alternativea.
0.0.0
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POTENTIAL LOCATION-SPECIFIC
(Continued)
AMP CRITERIA, ADVISORIES. AND GUIDANCE
COL
Jiff FEATURE
REQUIREMENT
STATUS
REQUIREMENT SYNOPSIS
CONSIDERATION III THE Rl/FS
Landfill §M leachate Popda
Federal Regulatory
Requirementa
State Regulatory
Requiremeota
RCRA - Standards for Owperi
••4 Operators of Permitted
Nasardoue Waal* FacllltiM
(40 CFR 264.IO-264.il)
•CRA - Preparedoesa and
Prevention (40 CPU 264.30-
264.37)
RCRA - Contingency PUn aod
Emergency Procedure*
(40 CFR 264.SO-264.S6)
RCRA - Croundwater
Protection (40 CFR 264.90-
264.109)
RCRA • Closure aod Post-
Closure (*C CFR 264.110-
264.120)
9
DCQC - Mazardou* Watte
Regulations, phase 1 and II
Relevant and General facility requirement* outline
Appropriate waale analyaia, aecurity measures, aod
training rcquireventa.
Relevant spd This regulation outlinea aafety equipment
Appropriate and aplll control requirementa for
hazardous waste facilitiea. Part of the
regulation includes a requirement that
facilitiea be deaigned, maintained,
constructed, and operated ao that the
possibility pf an unplanned releaae
which could threaten public health or
the environment is minimized.
Relevant and Tbia regulation outlines requirements for
Appropriate emergency procedures to be used following
explosions and fire*. This regulstioo
also require* that threats to public
health and the environment be minimised.
Relevant and Under tbia regulation, groundwater
Appropriate monitoring program requirements sre
outlined.
Relevant and Tbia requirement details the specific
Appropriate requirements for closure aod post-
closure of batardous waste facilities.
Relevant and These regulations provide a comprebeoaive
Appropriate program for the handling, atorage, aod
recordkeeping at hazardous waate
facilitiea. They supplement RCRA
regulations.
Treatment residuals from the waatewater treatment
facility will be diapoaed according to RCRA
Subtitle C.
RCRA requirementa must be considered when
evaluating eitenaions to the present landfill.
RCRA requiremeota must be considered when
evaluating eitenaioos to the present landfill. g>
A groundwater monitoring system must be installed
as part of any alternative. During site charac-
terization, the location and depth of monitoring
wells will be evaluated lor use in this monitoring
program.
A poat-closure plan is currently being developed
for the aite by EPA.
Because these requirements supplement RCRA
hazardoua waate regulations, they must alao be
conaidered at the CGLRT aite.
6.81.114
0111.0.0
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TABU 14
POTENTIAL ACTION-SPECIFIC ARARs
CCL
ARARS
REQUIREMENT SYNOPSIS
ACTION TO BE TAKEN TO ATTAIN ARAKS (IF NECESSARY)
RCRA • Standards for Owners cod
Operator* of Permitted Hatardous
Waste Facilities (40 CFR 244.10 -
(264.1)
RCRA - Preparedness snd Prevent-
ion (40 CFR 264.30 - 264.31)
RCRA - Contingency Plan and
Emergency Procedures (40 CFR
264.50 • 254.56)
RCRA - Hani testing, Recordkeeplng,
and Reporting. (40 CFR 264.70 *
264.77)
RCRA - Croundwater Protection
(40 CFR 264.90 • 264.109)
RCRA - Closure and Post-closure
(40 CFR 264.110 - 264.120)
OSHA - General Industry Standards
(29 CFR Part |910)
OSHA - Safety and Health
Standards (29 CFR Part 1926)
OSHA - Recordkeeping, Reporting,
and Related Regulations
(29 CFR 1904)
RCRA - 40 CFR 268 EPA Regulstions
on Land Disposal Restrictions
Genera.) facility requirement* outline general waste
analysis, security measure*, inspections, and train-
ing requirements.
Thia regulation outline* requirements for ssfety
equipment and spill control.
This regulation outlines th* requirements for
emergency procedures to be used following
explosions, fires, etc.
This regulation specifies the recordkeeping sod
reporting requirements for RCRA facilitiea.
This regulation details requirements for a ground-
water monitoring program to be inslslled si the site.
Toll regulation details specific requirements for
clofurt sod post-closure of hazardous waste facilities.
Tbjs regulation specifies the 8-bour time-weighted
average concentration for various organic compounds.
This regulation specifies the type of safety equip-
ment snd procedures to be followed during site
remediation.
This regulation outlines the recordkeeping snd report-
ing requirement* for sn employer under OSHA.
This regulation outlines land disposal requirement*
and restrictions for hazardous wastes.
All facilities on-site will be constructed, fenced, potted, snd
operated in accordance with this requirement. All workers
will be properly trained. Process waatea will be evaluated
for the characteristics of hazardous waates to assets
further landing requirements.
Safety and communication equipment will be installed at the
site; locsl authorities will be familiarized with site
operations.
Plant will be developed sod implemented during aite work
including installation of monitoring wella, and implementa-
tion of site remedies. Copies of the plsnt will be kept
oo-site.
Records of facility activities will be developed and main-
tained during remedial actiona.
A groundwater monitoring program ia a component of all
alternatives. RCRA regulations will be considered during
development of thia program.
Those parts of the regulation concerned with long-term
monitoring and maintenance of the site will be considered
during remedial deaign.
O
r-,
I
Proper respiratory equipment will be worn if it it
impossible to maintain the work atmosphere below the
concentrationa.
All appropriate ssfety equipment will be on-site. In
addition, safety procedures will be followed during
on-site activities.
These requirements apply to sll site contractors and
aubcontractors and must be followed during all site work.
Regulations to be phased in over the next few years require
contaminated soils to be treated to the Betl Demonstrated
Available Technology levels before being plsced or replaced
on the land. Hazardous waste cannot be stored except when
accumulated for recovery, treatment, or disposal. Land disposal
restrictions for PAH's bsve not yet been developed.
114
0.0
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14 (coo11)
POTENTIAL ACTION-SPECIFIC ARARs
CCl
AKAii
Requirement Bynopiti
Action to be Taken te Attain ARARs
CWA - 40 CFH P«rti 122, 12S
CWA • 40 CFP fart 403
CWA - 40 CHI Part 230
CAA - NAAQS for Tol.l Suspended
Particulars (40 CFR 129.10S.7SO)
Protection of Arcbeological
Resource! (32 CFR Part 229,229.4|
49 CFR Parts 107, 171.1-171.5)
DOT Rule* for TranaportatioQ of
Hazardous Materials (49 CFR Parti
107, 171.1-171.5)
DEQE - Hazardous Vaite
Regulations, Phaie 1 and 11.
(310 CNR 30.000, NGL Cb. Z1C)
General Lava Ch. Ill, Sec. ISO!
Any point aourca discharge* must meet NPDE8
permitting requirement!, which Include compliance
witb applicable water quality ataodardi; eetablisb-
•ept of a discharge monitoring system; aod routine
completion of discharge monitoring recorda.
Toil regulation apecifiea pretreatment atandardi
.for discharges to a POTV.
Tbit regulation outlinea requirement* for
discbargea of dredged or fill material. Under
tbil requirement, no activity tbat impacts a
wetland will be permitted if a practicable
alternative tbat baa leaa impact on tbe wetland
it available. If there ia no otber practicable
alternative, impacts mutt be Mitigated.
Tbil regulation apecifiea makimum primary and
•econdary 24-bour concentration! for particulale
matter.
Thil regulation developa procedure! for tbe
protection of arcbeological reaourcea.
Tbil regulation outline! procedurea for tbe
packaging, labeling, manifeating, and trans-
portation of bazardoua material!.
Tbil regulation provide! a comprehensive program
for the handling, atorage, aod recordkeepiog at
bazardoua waate facilitiei. Tbey lupplement
RCRA regulation!.
Under tbil regulation, the local board of health may
require a local aite aaaigiuaenl for bazardoui waate
treatment, atorage, and/or diapoaal faclltttea.
If groundwater that baa been treated by on-aite treatment
proceaiei ia discharged to surface watera oo-aite, treated
grouodwater must be in compliance with applicable water
quality atandarda. In addition, a diacbarge monitoring
program must be implemented. Routine discharge monitoring
records must be completed. •
If s leachate collection ayatem la installed and tbe
diacharge ia sent to a POTV, the POTV must have an approved
prelreatmeot program. The collected leacbate runoff must
be in compliance with the approved program. Prior to dia-
chargiog, a report must be submitted containing identifying
information, liat of approved permits, description of
operations, flow messuremeots, measurement of pollutants,
certification by a qualified professional, and a compliance
acbedule.
During tbe identification, acreening, and evaluation
of alternativea, the effecla on wellanda must be evaluated.
Fugitive dust emissions from site eicavation activities
will be maintained below 260 MB/"1 (primary standard) by
dust suppressants, if necessary.
If arcbeological resources are encountered during coil
excavation, work will stop until the srea has been reviewed
by federal and atale arcbaeologiata.
Contaminated materials will be packaged, manifested, and
transported to a licensed off-site disposal facility in
compliance with these regulations.
Because these requirements supplement RCRA bazsrdous
waste regulatiooa, they must slso be considered at the
CCLRT aite.
Tbe local board of health ahould be made aware of any
hazardous waate activitlea.
• .M.II4
0101.0.0
-------
TABLE H (con't)
POTENTIAL ACTION-SPECIFIC ARAIU
CCLRT FS
Requirement Synopsis
Action to be Taken to Attain ARARs
Kelt of 1982, Cb. 232, Bee. I50A
•od 150B •
DEQE - Air Quality, Air Pollution
(310 CHR 6.00 - 8.00)
DEQE • Wetlands Protectioq
(310 CHR 10.00)
HDWPC - Massachusetts Surface Water
Discharge Permit Program
(314 CHK l-PO-7.00)
NDWPC • Supplemental Require-
ment! for Hazardous Waste
Management facilities (314 CNR
8.00)
Waterways Regulations
(314 CMR 9.00 MCL Cb. 91)
Operation and Maintenance and
Prelreatment Standards for
Wastewster, Treatment Works, and
Indirect Discharges (31* CHR 12.00)
Implementation of M.C.L. C.lltr,
Employee and Community "Right to
Know" (310 CHR 33.00)
Worker "Right to Know" (441 CHR
21.00)
This regulation requires that notice be recorded io
tbe Registry of Deeds whenever certain types of solid
or hazardous waste activity occur on property.
This regulstion outlines tbe atandsrds sad require-
ments for air pollutioo control in tbe State of
Massacbuietts; all provisions, procedures, and
definitions are described.
Tbit regulstion outlines the requirements necessary
to work within 100 feet of s coastal or inland
wetland. Tbe set sets forth a public review
and decision-asking process by which activities
affecting waters of tbe stste sre to be regulated
to contribute to their protection.
This section outlines the requirements for
obtaining an NPDES permit in Massachusetts.
This regulation outlines the additional
requirements that must be sstisfied io
order for a RCRA facility to couply with the
HPDES regulations. These regulations apply
to a water treatment unit; a surface
impoundment that treats influent wsstewater;
snd a POTW that generates, accumulates, and
treats hazardous wast*.
This regulstion is prostqlgsfed to estsblish
procedures, criteria, and stsndtrds for
the watar quality certification of dredging
• P
-------
TABLE 15
COST SUMMARY FOR SELECTED REMEDY
CGL
Capital Costs:
Landfill Gas Incineration
Groundvater Extraction System
Groundvater Treatment System
Sediment Removal, Treatment, and Disposal
Discharge to Dunstable Brook
Total Capital Costs
$ 959,000
878,000
2,089,000
79,000
26.000
$ 4,031,000
Operation and Maintenance Costs:
Landfill Gas Incineration
Groundvater Extraction System
Groundwater Treatment System
Groundwater Monitoring System
Discharge System
Total Annual Operation and Maintenance Costs
$ 8,000/yr
42,000/yr
552,000/yr
138,000/yr
33.000/yr
$ 773,000/yr
Total Present Worth"' (with costs for discharge to
Dunstable Brook)
$11,320,000
*10% interest, 30 year pw factor = 9.427
6.88.114
0163.0.0
-73-
-------
EBASCO SERVICES INCORPORATED
APPENDIX A
EBftSCO
211 Congress Streel. 8lh Floor. Boston. MA 02110-2410. (617) 451-1201
September 29, 1988
REM-SMI-88-556
Ms. Kathleen James
Community Relations Coordinator
U.S. Environmental Protection Agency
Region I
John T. Kennedy Federal Building
Boston, MA 02203
Subject: REM III - ETA CONTRACT NO. 68-01-72
WORK ASSIGNMENT NO. 60-1L16
CHARLES GEORGE LANDFILL RECLAMATION TRUST
SUPERFUND SITE
FINAL RESPONSTVENESS SUMMARY
Dear Ms, James:
Ebasco Services, Incorporated is pleased to submit this
Final Responsiveness Summary of comments and EPA responses
to public comment received on the Feasibility Study and
Proposed Plan for the Charles George Landfill Reclamation
Trust site in Tyngsborough, Massachusetts.
If you have any comments or questions regarding this
submittal, please call Russell H. Boyd at (617) 451-1201 or
Richard Quateman at (617) 723-3860.
Sincerely,
Russell H. Boyd, Jr., P.E.
Ebasco Services Inc.
REM III Regional Manager
Region I
RHB/RG/es
CC: N. Barmakian (w/o encl.)
D. Dickerson
M. Amdurer
J. McAdoo
G. Vaillancourt
FILE: CHAR
-------
KB* III PROGRAM
REMEDIAL PLANNING ACITV
AT
TED UNOONrROLIZp HAZARDOUS SUBSTANCE DISPOSAL SUES
WITHIN EPA REGIONS I -IV
FINAL •RESPONSIVENESS SUMMARY
CHARLES GEORGE RECLAMATION TRUST LANDFILL SITE
TYNGSBOROUGH, MASSACHUSETTS
SEPTEMBER 28, 1988
Prepared By:
Approved By:
'Richard 1C QAoateman
Contnunity Relations Specialist
REM III/ICF Incorporated
Russell H. Boyd, Jr., P.E.
REM III Regional Manager
Region I
Ebasco Services, Inc.
-------
QF OCNTE3CS
Page
PREFACE 1
I. OVERVIEW OF REMEDIAL ALTERNATIVES CONSIDERED IN THE
FEASIBILITY STUDY INCLUDING IHE PREFERRED ALTERNATIVE 3
Figure 1. Charles George Site Jtep 3-1
II. BACKGROUND ON COMMUNITY INVOLVEMENT AND CONCERNS 6
HI. SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD
AND EPA RESPONSES 7
A. Summary of Citizen and Other Interested Party Comments 7
1. Comments Regarding the Phase I ROD:
Waterline Installation 7
2. Comments Regarding the Phase II ROD:
Landfill Cap 8
3. Comments Regarding the Phase III Proposed Plan 9
4. Future Use of the Site 11
5. Site Information ,11
B. Summary of Potentially Responsible Party
Comments 12
IV. REMAINING CONCERNS 15
ATTACHMENT A - COMMUNITY RELATIONS ACTIVITIES CONDUCTED AT THE CHARLES
GEORGE SITE
ATTACHMENT B - TRANSCRIPT OF THE AUGUST 17, 1988 INFORMAL PUBLIC HEARING
-------
Pr
The U.S. Environmental Protection Agency (EPA) held a public cxiimtait period
frcn August 4, 1988 to August 24, 1988 to provide an opportunity for
interested parties to cuuimit on the July 1988 Phase lU Feasibility Study
(FS) and the Proposed Plan prepared for the Charles George Reclamation Trust
landfill (Charles George) Superfund site in Tyngsborough, Massachusetts. The
Phase lU FS examines and evaluates various options,
alternatives, for addressing lanrifm gas emissions, leachate and groundwater
contamination, and contamination of sediments in Dunstable Brook. EPA
identified its preferred alternative for the cleanup of the site in the
Proposed Plan issued on July 21, 1988 before the start of the public comment
period.
The purpose of this responsiveness summary is to document EPA responses to
the comments and questions raised during the public comment period. EPA will
consider all of the comments summarized in this document before selecting a
final remedial alternative for the contamination at the Charles George
Reclamation tand-f-m Trust Superfund site in Tyngsborough, Massachusetts.
This responsiveness summary is divided into the following sections:
I. Overview of Rg^gdiai ftlt^rnativgg Consid^r**^ jfi the Feasibility Study
and Prorx?s^d Plan — f^ns section briefly ^Tfrl ir0*6 the y«*"«a<3iai
alternatives evaluated in the FS and Proposed Plan, including the
preferred alternative: biological treatment, metals precipitation,
carbon adsorption, and ion exchange for shallow groundwater and
leachate; deep bedrock groundwater and residential well monitoring;
incineration for landfill vent emissions; and, excavation, on-site
solidification and disposal of contaminated sediments.
II. Background on Community Involvement and Concerns - This section
provides a brief history of community interests and concerns regarding
the Charles George Landfill site.
III. Summary of Cmm>sn^'g Received nuking the P^Mic Comment P**T*iod and
Responses to These Comments - This section summarizes, and provides
EPA responses to the comments received from the public and other
interested parties during the public comment period. These comments
are organized by subject area. In addition, comments received from
the Potentially Responsible Parties are summarized along with EPA's
responses.
IV. Remaining Concerns - This section describes issues that may continue
to be of concern to the community during the design and implementation
of EPA's selected remedy for the Charles George Landfill site. EPA
will address these concerns during the Remedial Design and Remedial
Action (RD/RA) phase of the cleanup process.
-------
Attachment A - dis attachment provides a list of the commonity relations
activities that EPA has conducted to date at the Charles George
site.
Attachment B - Transcript, of the August 17, 1988 Informal Public
held in Tyngsborough,
-------
I. OVERVIEW OF REMEDIAL ATZEEFNAT1VUS CCNSHERED IN tfflE FE&STTm.TTV S1DDY AND
PROPOSED HAN
Using the information gathered during the Phase in Remedial Investigation
(RT) — a study that investigates the nature and extent of contamination at
the site — and Risk Assessment — a study that assesses the potential risks
to human health and the environment aggnrjat-ari with the site contamination —
EPA identified several objectives for the cleanup of the Charles George site.
(See Figure 1 for a nap of the Charles George site. ) The objectives are:
i
(1) Reduce potential risks posed by contact with contaminated sediments in
Dunstable Brook and the tributary originating at the landfill;
(2) Reduce potential health risks posed by drinking contaminated
groundwater near the site;
(3) Reduce public health risks posed by breathing landfill gas emissions;
(4) treat or dispose of landfill leachate as required by £B&'s Phase n
1985 Record of Decision.
After identifying the cleanup objectives, EPA developed and evaluated
potential cleanup alternatives. The Phase III F5 report describes the
alternatives considered for addressing contamination of groundwater and
leachate, landfill gases, and sediments, as well as the criteria EPA used to
narrow the list to sixteen potential remedial alternatives. Ihree of these
alternatives were chosen by EPA as the combined preferred alternative to
address the different aspects of site contamination.
Each of the sixteen alternatives is described briefly below. The July 1988
Proposed Plan should be consulted for detailed explanations of the preferred
alternative.
Alternatives Evaluated for Treatment of Groundwater and Landfill Leachate
1. No Action. The no-action alternative would involve long-term monitoring
of shallow and deep groundwater with a review of site conditions every five
years to determine if additional cleanup activities were necessary. While
groundwater would not be treated, a separate leachate treatment program would
be instituted.
2. Extraction. Biological Tr^^tJnent and Disch^Trre (PPA/S Preferr
-------
landfill, if feasible. If this is not determined to be feasible, the sludge
would be placed in a federally approved hazardous -waste facility. A pilot
test of the leachate and groundwater treatment system will be conducted prior
to full scale inplementatim of the cleanup.
3. ExtidcLion. ("^Tljon A^^uiuticn. and DJgf"friarge. This alternative would
utilize the same extraction and treatanent system as the preferred alternative,
except that it would include extraction of eastern deep bedrock groundwater
and it would not include biological Lrtiatiimit. Treated water would be
discharged to Dunstable Brook, the Merrimack River, or reinjected into
groundwater.
4. Extraction. Air Stripping, and Pisciiaiue. This alternative is similar to
the above alternative, except that air stripping would be added to the
treatment process. Air stripping involves punping the groundwater into a
vertical column through which air is forced to remove, or strip, volatile
organic compounds (VDCs) from the water.
5. ZxLrdc*"von. Off— site TreaLiitniL. and Disch^TTre. In this alternative,
groundwater and leachate would be collected and trucked off site to an EE&-
permitted hazardous waste treatment facility.
Alternatives Evaluated for Treatment of landfill fv^ Emissions '
6. Mb Action. In this alternative, landfill gas emissions would be
discharged to the atmosphere without treatment.
7. On-site Incineration (EPA's Preferred Alternative) . In this alternative,
landfill gases will be collected with a series of gas vents and piped to an
on-site incinerator where the contaminants are destroyed at a temperature of
greater than 1200 degrees Fahrenheit. After start-up, the incinerator will be
fueled by the methane present in the vent emissions.
8. Gas Flaring. In this alternative, landfill gas emissions would be treated
to remove acidic ccnpounds and then burned in an on-site gas flaring unit.
9. Combust ion/Medium Btu Gas Recovery. In this alternative, landfill gases
would be collected through a combination of the vent system and a series of
deep gas wells throughout the landfill. The collected gases would be piped to
an internal combustion engine that would burn the gas to produce electricity.
Alternatives Evaluated for Treatment of Sediments
r
10. No Action. In this alternative, the contaminated sediments would be left
in place in Dunstable Brook and a tributary to the brook. EPA would review
site conditions every five years to determine if remedial actions are
necessary.
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11. Pamirn/al,. On—site SoilldTf icgftion. and Pi^P^y*! Qf ^Tt^^jjLUhsted Brook
sediments in Dunstable
Brook and a tributary to the brook will be excavated, combined with a
solidifying material such as Portland cement to stabilize the contaminants,
and rijgrnnMri on-site under the landfill cap.
12. On-site Capping. This alternative would involve covering, or capping,
sediments in the brook and tributary with a synthetic fabric and fbur-to-sdbc
inches of crushed stone.
13. Excavation. Tty^nraT Aeration, and BibLE**^- This alternative would
require excavation of contaminated earHmcnt-g followed by thermal treatment in
which hot air would be forced through sediments to remove VDCs. Air emissions
would be treated prior to release to the atmosphere, and treated sediments
would be placed on the landfill for capping.
14. Excavation. Off-site Solidification, and Disposal. In this alternative,
contaminated sediments would be excavated and shipped off-site to an approved
hazardous waste treatment facility for solidification and disposal.
15. Excavation. Incineration,. and 9i*ij!T'nj!rAl » In this alternative,
contaminated sediments would be excavated and shipped off-site to an approved
hazardous waste incineration facility where the contaminants would be
destroyed at high temperatures.
16. Excavation and On-site Disp^al. This alternative would entail
excavating contaminated sediments and placing them in the landfill. The
sediments would be contained by the landfill cap once it is completed.
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BACKGROUND CN QCWdNTTX UMJDUEHEHT MID GGNCS&S
The Charles George landfill site is a 70-aore municipal and industrial
waste landfill located approximately one mile southwest of the town of
Tvngsborough, Massachusetts. A portion of the site is also located in
neighboring Constable, Massachusetts. A 96 unit condominium complex is
located within 800 feet of the site. In addition to municipal and industrial
waste, the landfill owners accepted hazardous waste from 1973 through at least
1976. EPA involvement in the site began in 1981 with a field investigation of
groundwater contamination. Local residents have been very active in landfill-
related issues for over a decade. Initial concerns focused on dust and noise
associated with the landfill operation, and later turned to concerns over the
hazardous wastes disposed of at the site. On two separate occasions
Tyngsborough residents formally voiced their opposition to the operations of
the landfill. A formal condominium owners association focusing on groundwater
pollution concerns was formed in the early 1980 's, and a separate neighborhood
association concerned with contamination of Flint Pond and Marsh *igo
developed. A formal citizens advisory committee (CAC) was formed in March
1987. EPA representatives regularly meet with the CAC to discuss issues of
community concern surrounding the landfill and the results of on-going EPA
investigations.
The principal community concerns are summarized below:
Ifra**e I Waterline Installation
Citizens expressed concern about the time it is taking for EPA to connect a
permanent waterline to the condominium conplex.
Groundwater Treatment
Residents expressed concern about the amount of sludge that would be
generated by the groundwater and leachate treatsnent plant, and stressed their
apprehension over EPA's plans for on-site disposal of the sludge.
Flint Pond and
Residents expressed strong concerns about the possible contamination of
Flint Pond, noting that area children regularly use the pond for swimming.
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UI.
SUMARY OF COMMENIS
DCRDG
PUBLIC CCMffiNT H3UJUU AND EPA
This responsiveness summary addresses the comments received by EPA
concerning the draft FS and Phase III Proposed Plan for the Charles George
Tandf i 1 1 Superfund site in Tyngsborough, Massachusetts. Five sets of
written cements were received during the public cuinitmt period (August 4 -
August 24, 1988) : One from the Town of Tyngsborough Conservation Ccranission,
two sets from the Potentially Responsible Parties, and tud letters from
concerned citizens. In addition, the EPA Project Manager answered jjifumvO.
questions from the public. Copies of the transcript of the August 17, 1988
informal public hearing are available at the Tyngsborough Board of Health,
Tyngsborough Town Hall, 10 Kendall Road; Littlefield Public Library, 252
Middlesex Road; and, the EPA Records Center at 90 Canal Street, First Floor,
in Boston, Massachusetts.
A. Summary of Citizen and Other Interested Party Comments
These comments, along with EPA responses, are summarized and organized into
the following categories:
1. The Phase I Record of Decision (ROD) : Waterline Installation
2. The Phase II ROD: landfill Cap
3. The Phase III Proposed Plan
4. Future Use of the Site
5. Site Information
ing the
I ROD; Wa'tfi-line installation
Comment 1. A town official stated that the Flint Pond area has received
intermittent contamination from landfill leachate and that the wells in the
area should therefore be considered threatened. The commenter further
stated that EPA should amend the Phase I ROD to provide users of these
wells with municipal water.
EPA Response; Remedial Investigation (RI) data do not provide absolute
proof that contaminant sources other than the Charles George landfill are
responsible for low contaminant concentrations in Flint Pond area wells.
However, the following three findings based on RI data suggest that
contamination in these wells was not derived from the Charles George site.
1. Existing hydraulic data do not indicate that groundwater is moving in
the northeastward direction from the site to these wells. The actual
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8
flowpath appears to be approximately 45 degrecis off course, Two factors
could cause the plume to deviate to the north. First, the Town of
Tyngstorough may be pumping enough deep groundwater to create hydraulic
gradients in this direction. Second, conductive bedrock fractures could
run in the northeast direction under Flint Pond. If these two conditions
exist, Flint Pond well contamination could be due to Charles George
contamination. Charles George contaminants would not reach these veils in
detectable levels via transport through Flint Pond or shallow groundwater
in glacial sediments.
2. Unless the Town of Tyngsborough H*g been pumping a large quantity
(greater than 100 gallons per minute [gpm] ) of deep bedrock groundwater for
many years, contamination from the Charles George site has not had
sufficient time to reach Flint Pond area wells (based on measured
gradients) .
3. Because none of the wells have shown consistent levels of
contamination, there is no conclusive evidence of a plume in the Flint Pond
area. Also, the one-time flow levels of several compounds do not suggest a
conductive fracture or a correlation with well depth. Contaminants
identical to those found in landfill groundwater have not been detected
more than once in any individual well in the Flint Pond area.
EPA plans to continue the residential well monitoring program as well as
additional groundwater monitoring to provide continuing data on the
potential for groundwater contamination from the landfill to impact the
Flint Pond residential area. Appropriate remedial action, possibly
including an extension to the water line, will be implemented if a
contaminant plume exhibiting unacceptable human health risks is discovered.
2. Comments Concerning the Phase II ROD: Landfill Cap
Comment 2. A town official noted that little information is available on
the long-term durability of synthetic caps for an area as large as the
Charles George Landfill. The commenter requested that EPA institute a
monitoring and maintenance program to ensure the continuing integrity of
the cap.
EPA Response: The integrity of the cap will be monitored and maintained as
part of the post-closure activities for the landfill. These activities
will include nearby groundwater monitoring and visual inspection of the
liner material via the 20 inspection ports designed into the cap.
Continued surveying of the landfill is also being done to monitor landfill
settlement and to analyze potential impacts on liner integrity. All post-
closure activities including appropriate responses to potential problems
are presently being finalized in a Post-closure Plan.
Comment 3. A number of citizens expressed concern over potential erosion
during cap construction and urged EPA to implement an effective erosion
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trol
EPA Response: The specifications for the cap project include a requirement
for complete perimeter erosion control vising stacked hay bales car pre-
assembled silt fence structures. The specifications also require the
construction contractor to submit an erosion control plan for ERA review
and approval. Par •ftjy^J^T* information, ^°ft yaftHrr^ Q2150 of frh*» larrikin
cap specifications.
CunnifciiiL. 4. A town official questioned if EPA plans to 'disturb the landfill
cap after it is constructed in order to install the leacnate treatment and
vent collection systems. The commenter expressed concern over the timing
of the operation.
EPA Response: The landfill liner will not be disturbed by construction of
either the leacnate treatment system, the vent emission collection system,
or the incinerator. The collection systems for both the leacnate and the
landfill gas will be installed as part of the cap project. The upcoming
Phase TTT remedy will implement the cleanup by installing and connecting
the on site treatment systems to the collection systems.
Comment 5. A Town official stated that all sludge from the water treatment
plant and all sediments excavated from Dunstable Brook should be disposed
of off site.
EPA Response: Sludge from the leacnate and groundwater treatanent system
will be disposed on site only if it is found to be a feasible option for
disposal according to the requirements of Subtitle C of the Resource
Conservation and Recovery Act (RCRA) for secure disposal of hazardous
waste. These requirements include the installation of two or more liners
with leacnate collection systems above and between each liner. The
treatment plant sludge will be dewatered and should not release
contaminants. The sludge also will have a sufficiently high pH so that
metals are rendered insoluble and will, therefore, not easily be released.
If it is determined that construction of a secure extension of the landfill
is not feasible, the sludge will be disposed in an off-site facility.
Disposal of Dunstable Brook sediments under the landfill cap will
significantly reduce the mobility of the polynuclear aromatic hydrocarbons
(PAH) sediment contaminants. Solidification of the sediments will further
reduce their mobility. Sediments with higher PAH contamination are being
similarly managed on site by using the designated spoil disposal area of
the capping project. The incremental contamination and associated risks
from Dunstable Brook sediments will be negligible.
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10
Comment 6. One commenter imjal EPA "bo install air pnllntinn control
devices on the vent gas incinerator.
EPA Response: Air pollution devices will be installed on the incinerator
if air sampling indicates that permissible air quality standards are
exceeded. Continuous air monitoring equipment will be installed to measure
carbon monoxide, oxygen, and total hydrocarbons in the stack emissions, and
downstream, on-site plume sampling will be done to monitor sulfur dioxide,
nitrogen dioxide, carbon monoxide, and volatile organic compounds (VOCs).
*
Cuuntait_.7. A Town official expressed concern over the quality and
timeliness of the data collected in the Phase HI RI. The commenter
questioned the lack of current data on water quality in residential wells
and the impact of "laboratory contamination" of site samples.
•
EPA Response; Concerning the air investigation of the RI, the dual
objectives of the air monitoring and modeling were to (a) establish the
nature of any risks posed to public health or the environment under the
current, uncaged condition of the landfill, and (b) predict the nature of
risks posed under the future capped, vented condition of the landfill. The
air study established that off-site risks due to gaseous emissions were low
under both current and future conditions, exceeding EPA's target risk range
only under worst-case conditions. Most significantly, however, results of
the air study indicate that on-site risks due to potential exposure under
either current or future scenarios would be at levels considered
unacceptable to EPA. As a result, the remedial alternative splpcfpri will
include incineration of vented landfill emissions. This action will jneduce
future on-site risks to a level considered acceptable, and will reduce off-
site risks to levels significantly below those currently existing.
Concerning the residential well data, recent sampling done by EPA supports
the conclusions discussed in the RI and in this responsiveness summary.
The results of this sampling and all future sampling will be included into
a database and made available to the public. "Laboratory contamination"
usually refers to the detection of low parts per billion concentrations of
cleaning solvents, but can also include similarly low levels of phthalates
dissolved from plastic or rubber sampling equipment. These low levels do
not interfere with the detection of other contaminants.
Comment 8. A Town official reminded EPA that any off site remediation
activities that affect wetlands must be conducted in accordance with State
and local wetland regulations. The commenter expressed the willingness of
the Town to work with EPA to find solutions that will allow EPA to conduct
the cleanup.
EPA Response: Excavation of Constable Brook sediments will conform to all
the substantive requirements of Federal, State, and local wetland
protection requirements. Impacts will be minimized by using silt curtains
and oil boons, and by restoring the impacted wetland area to its original
condition.
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11
4. Future Site Use
Garment 9. A number of citizens asked what EPA would do to
inappropriate future development of the Charles George site. Citizens
stated that a ban on new M»Vlg that "-"i* tap the contaminated deep aquifer
should be instituted.
EPA Response; As discussed in the Phase HI POD, jjqplHtentatinn of
institutional controls over de*r bedrock grcundwater use would increase the
protectiveness of the remedy. EPA will work with the State and Town in
developing appropriate zoning or deed controls, and in evaluating
development proposals involving large-yield pumping.
5. Site Information
A town official stated that EPA has not made site information
available to the public in a timely fashion, and also noted that the Town
Hall information repository lacked documents.
EPA Response: EPA made the PI, FS and Proposed Plan available to the
public as scon as possible. The 75 and Proposed Plan were sent out well in
advance of the public comment period to provide tune for review. The RI
was made available as soon as it had been finalized. All don merits were
hand delivered or express mailed to the two local information repositories,
The Tyngsborough Board of Health at the Tyngsborough Town Hall and the
Littlefield Public Library, before the start of the comment period.
Apparently, for reasons unknown to the Agency, Volume II of the RI was not
available at the Town Hall by the start of the comment period, although it
had been express mailed on August 1, 1988. Volume II was available at the
Littlefield Public Library, however, since it was also express mailed on
August 1. Volume II was nade available at the Town Hall, along with
another complete set of documents for the Town Clerk, on August 22, 1988.
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12
B. Summary of Potentially Pm-p«»MKi«» Parties (EBP)
Comments received from the PRPs, and ZPA's responses are summarized in the
following section.
Comment 1. Ihe PRPs support and encourage EPA's plans to conduct pilot and
pre-design studies of the leachate and groundwater treatment technologies.
Pilot testing of the vent gas incineration system is also suggested.
EPA Response: Pilot testing of other gas treatment systems before
completion of the landfill cap and gas collection system is impracticable,
and the delays that would be caused by pilot testing are unacceptable.
Once the incineration system is implemented, however, safe pilot-testing of
other treatment systems could conceivably, be done by routing vent gases
through the pilot plant, and then routing pilot-plant effluent gases to the
incinerator. Auxiliary fuel would most likely be needed for the
incinerator if pilot testing were done in this manner.
Comment 2. Shallow groundwater contamination should be further evaluated
to determine if treatment is actually required to protect public health and
the environment. Naturally occurring levels of arsenic should be
determined.
EPA Response: EPA acknowledges that the eastern overburden aquifer could
meet the target levels established in the Phase III ROD before the other
contaminated aquifers. As described in the ROD, treatment of this aquifer
is only required if target levels are exceeded. A two-stage extraction
system in the eastern area could be advantageous and will be investigated
during remedial design. If found to be feasible, it will then be
implemented. Arsenic concentrations in uncontaminated groundwater around
the landfill will be further evaluated as a result of the post-closure
groundwater monitoring, and these results will be given appropriate
consideration in evaluating whether the arsenic target level should be
readjusted. It should be noted, however, that during the 1987 Remedial
Investigation, arsenic was detected in the contaminated southwestern and
eastern plumes (including the shallow eastern plume) only.
Comment 3. EPA should investigate the feasibility and cost-effectiveness
of treating landfill leachate and groundwater separately.
EPA Response: If the pilot-testing discussed in the Phase III ROD
demonstrates that it is cost-effective to treat groundwater and leachate
separately, then design and operation of the treatment system(s) should
follow accordingly. If treated separately, however, both leachate and
groundwater must individually meet the target cleanup goals before being
mixed together for discharge.
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13
Comment 4. Solidification of Unstable Brook sadiaents, p-l"r to
in the landfill, is unnecessary,
EPA Response: Solidification of SHliiaaiLs provides for a more permanent
remedy, and it satisfies CERdA's statutory preference for treatment as a
principle element. Also, depending on the season, solidification of
sediments may be necessary to meet construction requirements for amppfahio
fill to be used in the capping project.
CunnaiL 5. Details and projected costs of the deep bedrock groundwater
"early warning" monitoring system fh^ti^ be provided.
EPA Response: The Phase HI POD describes the scope of the groundwater
monitoring plan, and explains that more specific details of the plan will
be developed during remedial design. Costs for the monitoring as presently
projected are included in the ROD.
Cmiimait 6. The time allowed for PRP and general piKijr? review of the Phase
IIT Remedial Investigation study was inadequate.
"EPA "Response; The RI and the FS were distributed to the PRPs and placed in
the public information repositories before the start* of the public cxinueiit
period. In fact, EPA finalized and distributed the FS before final
printing of the RI in order to provide the PRPs and the public a chance to
read the FS (which contained a discussion of the contamination detected
during the Remedial Investigation) before the start of the juuimeiiL period.
The twenty one day comment period is consistent with the current National
Contingency Plan (NCP) .
Comment 7. Off-site disposal of leachate by trucking to a RCRA facility
should be re-evaluated during the pilot studies.
EPA Response: Should off -site disposal of leachate to RCRA facility prove
to be a viable option in the future, EPA will consider implementation of
it.
Comment 8. The cleanup criteria for sediment removal of 1.0 part per
million (pom) for PAHs should be reconsidered. A 20 ppm level would result
in a risk that would fall within EPA's target range of 1 x 10"4 to 1 x 10~7
for carcinogenic risk.
EPA Response: Under the worst realistic case, the carcinogenic risk (8.2 x
10~5) associated with a target clean-up level of 20 ppm would be at the
uppermost limit of the EPA target range. Because a target clean-up level
of 1 ppm would result in a risk (4.1 x 10~6) at the lower end of the range,
it would be more protective of human health and the environment at the
Charles George site.
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14
Comment 9: Ihe southwesterly sedimentation basin oTthe landfill cap
should be relocated.
EPA Response; Appropriate engineering responses will be implemented to
ensure that surface water £11111 this sedimentation basin will not recharge
the groundwater extraction system in the area.
CunuimiL 10; Alternative methods of disposal should be considered for the
contents of the landfill lagoons during Phase II'cap construction.
«
EPA Response; EEA, together with the U.S. Army Corps of Engineers, will
consider alternative methods for disposing of the lagoon contents. The
possibility of using the proposed percolation pits as lined holding ponds
will be investigated. Biis cmild allow for a source of pilot plant
influent.
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15
IV. REMAINING GGNCEfOE
During the public tiiniiuiiL period, act the public informational mooting en
August 3, 1988, and at the informal public hearing held in Tyngsborough on
August 17, 1988, EPA representatives and Inral residents and officials
discussed Issues of community concern as the site moves into the design and
implementation phase of EPA's selected remedies for the Charles George
landfill site. These issues and concerns are described briefly along with EPA
on how the Agency intends to aririrpss these concerns.
(A) Sludge and TmaLmmt Residuals
Citizens agv^rf EPA to provide more exact figures on the expected amount of
sludge to be generated by the water treatment plant along with detailed
plans for disposal of the sludge.
Pg*=ponse; Hie PS conservatively ggfrjpat-orf that apppnaH mat^»i y 200
pounds per day of sludge from the biological treatment unit and 1400 pounds
per day of sludge from the metals precipitation unit would be generated.
As discussed previously in this responsiveness summary and in the ROD, on-
site sludge disposal will occur only if found to be feasible and capable of
meeting RCRA standards for hazardous waste disposal. These standards
include extremely protective engineering requirements, including
installation of at least two liners with leachate collection systems above
and between each liner.
fB)
Citizens remain concerned that additional homes in the Charles George
landfill area may have contaminated wells. Citizens have asked EPA to
further investigate wells in the vicinity of Flint Pond and provide an
alternative water source to these homes.
EPA Response: As previously discnsspri, EPA will continue the residential
well monitoring program, and will implement appropriate water supply
responses if landfill contamination poses unacceptable risks to human
health via groundwater.
rage Tanks
Citizens noted that possible emissions from the leachate storage tanks
could contain VDCs, and stated that EPA should consider connecting the
tanks to the landfill vent emissions incinerator.
EPA Response; During the Remedial Design phase, EPA will consider
connecting the leachate storage tank emissions to the landfill vent
emission incinerator system.
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ATTACHMENT A
COMMUNITY RELATIONS ACTIVITIES
CCNDUCXED AT THE
CHARUES GEORGE REOAMATICN TRUST IANDFHL SITE
IN TYNGSBOROUGH, MASSACHUSETTS
Community relations activities conducted to date for Phase TIT
activities at the diaries George Superfund site include:
i
o November 1986 - EPA released a fact sheet to inform the public
about the preliminary findings of the Remedial Investigation (RI)
and Endangerment Assessment.
o November 20, 1986 - EPA held a public informational meeting to
discuss the preliminary findings of the RI and Endangennent
Assessment.
o 1987 - On several occasions, EPA and T3EQE staff have met with
residents and local officials to discuss local concerns and
remedial activities.
o August 1987 - EPA released a revised community relations plan to
provide an update of community concerns and community relations
and remedial activities.
o July 1988 - EPA issued a public notice to announce the time and
place of the Feasibility Study (FS) public informational meeting
for the site and to invite public comment on the FS and Proposed
Plan.
o July 1988 - EPA mailed the Proposed Plan announcing EPA's
preferred alternative for addressing contamination at the site to
all those on the site mailing list.
o August 3, 1988 - EPA held a public informational meeting to
HjgnicLg the results of the FS and the Proposed Plan.
o August 4 - August 24, 1988 - EPA held a public comment period on
the Proposed Plan.
o August 17, 1988 - EPA held an informal public hearing to accept
comments on the remedial alternatives evaluated in the FS and
Proposed Plan.
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1
2
3
4
5
6
7
B
9
1C
11
12
12
ATTACHrtiNT B (APPENDIX A)
UNITED STATES OF AMERICA
ENVIROIvHENTAL PROTECTION AGENCY
BOSTON REGION
1-8
| In the Matter of:
jl
II SUPEHFUND PROGRAM
!i
i: CHARLES GEORGE RECLAMATION
• TRUST LANDFILL SITS
j TYNGSBOROUGH, MASSACHUSETTS
August j7, 19SB
Auditorium
Tyngsborough High school
50 Norris Road
Tyngsborcug.i, Ilassachu?etts
;^ Whereupon the above entitled Master cair.e en for
15 hearing pursuant to Notice at 7:50 P.M.
16
17 BE>ORE:
18 R"CK CAVAGNERO, Chief-Massachusetts '^uoerfuniJ -ection
19 DAVE DICKERSON, Remedial Project manager
20 : DALE YOUNG, Massachusetts D.E.Q.E.
21 ,
22
23
24
25
APEX Reporting
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D E
2
SPEAKERS .. PAGE
Richard A. Cavagnero "3
4
David Dickerson .5
8 I1
9 M
10 ,
ii ;
i:
IS
16
17
18 :
19 :
'i
20 ;
i
21 I1
,i
ii
22 I'
i
23 i'
24 I
APEX Reporting
A'. :.-•>.',•'. ,//',„.•. ..,.,„,;/ A1-;..,-/
i'jl7'i I.1',- tit.~7
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1 PROCEEDINGS
2 (7:50 p.m.)
3 '' MR. CAVAWJ.fc.ROi We're going~to get started, if
4 i everyone's ready. My name is "Rich Cavagnero, I'm the Chief
of the Massachusetts Superfund Section of EPA, and with me
to my left, your right I guess, is Dave Dickerson, who's the
7 f Remedial Project Manager for the Charles George Land
8 ji Reclamation Trust Site in Tyngsborough, and on my other side
9 I1 is Dale Young, who's our contact frcm the Massachusetts
1C , Department of Environmental Quality Engineering, DEQE.
r The purpose of tonight's meeting is, for most
12 of yru -..'V.c were heir back on August 3rd, we had a public
12 rectirg nt vhich D = v= ar.d E. C. Jordan, our contractors, explained
i.i the results of the feasibility study, what option? had been !
i
• i
15 looked at, and also EFA's proposed plan, that is what we're i
i
16 , leaning towards as far as a remedy for the Charles George j
17 site. !
18 .: We're here tonight to basically hear what you i
19 ; have to say about that proposed plan or the feasibility study. :
i
20 We have people from Apex Recording here who will be transcrib- :
i
i
21 \ ing any comments made, and we'll be producing a transcript.
J!
22 I This transcript will go into what we call the Administrative
23 ' Record, which will be used, along with all the studies that
24 ' EPA has done and the comments subnitted by the State, and
25 •! any written cozmerts submitted prior to the close of the cociml
APEX Reporting
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4
period on August 24th, and based on all this material, EPA
will come to a final decision on a remedy at this site and
3 i
will issue something called a Record of Decision, which will
be a document that explains in some detail what we found at
5
the site, what the problems are, what options were looked
at, and why we chose the option we chose.
M *
7 ''
!' It will also include a portion called the
|i
8 ;; ness sumnaTy, which will be a response to all comments submitted,
:; I
9 :' either orally tonight at this hearing or written comments. J
'c . So you have ycur choice, you can do either or both. And as i
11 ., I mentioned the last time we were here, we do feel it's necessary
I
H .. to got your cements because we do war.t to take then into
i
12 account before we cone to a final decision. i
'- ; So to reiterate, the comment period does close >
15 :' on August 24th. In order for your connent£ to be considered j
16 .< before decision is. made, we need then to our office, postmarked:
i
i
17 by that date or orally tonight. :
I
i
16 • Dave Dickerson will briefly rehash for you, :
i
19 < although it seems to be the same people here, but once again '
20 ; he'll rehash EPA's preferred alternative, after which we will !
2i j; start the formal part of the hearing, if you will.
i
22 I If you are going to make a statement, we would
23
ask that you fill out one of the forms, just with your name
24 I and address, so that we make sure we get it right for the
i.
j!
25 '! hearing transcript. And once all the statements are made,
i
j; APEX Reporting
I' /Y/i'M/vW Prof' \iii»i'ti /\if.'nrfr\
(>il71 -t'21'i- -JU77
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5
we'll close che hearing officially, and Dave and I and Dale
M
M
2 ij
! will hang around and cake questions and answers, if you have
3 j any.
So with chat, I'll turn it over to Dave
,.. ,
TJickerson.
6 ij MR. DICKEHSON: Thank you, Rich.
7
r
Just to recap the proposed plan, if anyone
8 • wasn't here and needs an update, our proposal, basically,
9 ' consists of three main parts, the treatment of groundwater
I
12 and leach'ate, treatment of the landfill gas emissions, and j
' * !
'• _ the treatment of some contaminated stream sediments. j
II . Taking the groundwater and leachate first, |
i
13 x'e propose to extract contaminated shallow groundwater from I
'«: two areas near the landfill. One area is in the southwestern i
•; i
15 part of the landfill and the other area is on the eastern !
i
16 .part of the landfill, right next to Route 3. Those two plures ,
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17 would be combined with leachate collected as part of the '
i
15 capping system, ar.d treated on site to drinking water standards.
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19 After monitoring to make sure we met chose !
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20 standards, the treated groundwater and leachate would Chen j
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2i •; be discharged into Dunstable Brook.
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22 ' In addition to that groundwater and leachate
23 !' treatment, we would have an upgrading in groundwater diversion
24 ; trench that would lower the groundwater table beneath the
25 "landfill, and that water would also get diverted to Dunstable
i
! APEX Reporting
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1
2
6
: Brook after monitoring, to make.sure that it was siill clean.
In addition, we would propose.to monitor deep
3 !
! bedrock ground water as well as private drinking wells to
4 I
; make sure that people's wells were safe to drink.
To go into just a little bit of detail OB the
6 i
{ on-site treatment plant, it would be comprised of three, perhap
7 j!
j, four treatment schemes. The first would be biological treat-
8 !'
" ment, the second would be metals prescipitation, the third ,
9 ;!
|. would be carbon adsorption, and if necessary, ion exchange, j
': if we hadn't net our drinking water standards yet.
11 "
Moving on to the landfill gas emissions, we
12 '
propose to collect the landfill gas from the 28 vents that
12 !
will be installed as part of. tie capping system, pump those j
/ emissions to a fune incinerator on site and estroy the compounds
15 , ,
of concern in the gas e. ... ons in that incinerator.
16
i Moving on to the stream sediments, contaminated •
sediments in a short section of Dunstable Brook to the uest
i - '
18
: of the landfill would be dredged, brought to the site, solidified,
19' i
ii using cement-like substance, placed on the landfill, and :
' i
; covered as part of the landfill with the synthetic landfill i
i • i
21 i; cap- i
23
24
i
j So that's a very, very brief description of
I
i
the proposed plan. Again, it's treatment of groundwater and
! leachate, air emissions, and some stream sediments.
25 j Rich?
APEX Reporting
i-i \li-ri'i l'rnt''*\tiinril Rtf)
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1
j MR. CAVAGNERO: Thank you, Dave. We will now
2 «
ij basically, open the hearing., to comments,.... We would ask that
3 :' •
! if you want to .make a comment, if you could come down to the
4
mike, which is not an amplifier but is hooked up to Apex
Recording, so that we make sure that we get your statement
6 i!
;j right, and we would like you to identify yourself by name
7 j'
|j and address and any affiliation, if you have one.
8- i1
; (Pause.)
•i
9 •<
.MR. CAVAGNERO: Well, no one wants to make
10 ,.
, a connent, it's going to be a short hearing.
i
11 '
Okay. We do have your option of sending it
to us in writing, and we hope that we will hear fron you.
T'
David's address is in the fact sheet, and proposed plan, we
*A '
!' do have some handouts here, I believe most of you are probably |
on the nailing list and have that. j
i
The administrative record is located at the
Littlefield Library, and there are copies of the feasibility '
is : !
: study and proposed plan at both the Littlefield Library and i
19 !; Tyngsborough Board of Health, as well as at out office, EPA's •
20 i office at Canal Street in Boston. j
! j
So if there are no comments, my first time |
22 ' ever at a hearing where we had none, but we will close the
j;
23 !' hearing and entertain any questions that anybody may have.
24 [ (Whereupon, at 7:58 p.m., the hearing was
2^ J concluded.)
APEX Reporting
i-!ll>tfTid l'n>fr\Ui)'ia! Kfpint'i i
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CERTIFICATE OF "REPORTER AN'D TT-ATTS CRISES
This is to certify that the attached proceedings
bef = re EWVTP.ONMZNTr-vL PROTECTION 7.GEUCY
ir. the Matter of:
SUPERPUND PROGRAM
CHA7.LES GEORGZ RECLAMATION
TRUST LANDFILL SITE
TYNGS30ROUG1I, MASSACHUSETTS
• x- /-% *-
Place: Tyngsborough, Massachusetts
Date:. August 17, 1983
:ld as herein appears, and that this is the true,
:e £r.d cc.~.plete transcript prepared from the r.ctes
rsccrdir.c = taker, cf the above titled crcceedinc.
/q p
J. Rasmus sen B/?VRR
Date
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APPENDIX B
NFWSWEEKLY, THURSDAY, JULY 2*. IMS
O» Ihe Phas« m Fr MlMHly Stsrfy A»d Proposed
FwTh*
/' >.-•
.•£-.vif.-s'jrV.vjr ;-••- .
• v- -^Vi:-. !..'•..>.•*•.-
aPhas«nr<
The U.S. Environmental Protection Aacnc> (EPA)
Feasibility Study (FS) that evaluated cleanup alternatives to address^
Charles George site in Tynpborough, Massachusetts.'The Phase ID n mfcuiiil ilsu
natives to address contamination in leachatc lad gasemissioosjt txjcsitcas weJlataiKer-
natives to address contamination ia off-sUeYeat. naarrl im the Phase ffl FS*£PA nej'
selected a pieferied deaoap alternative for the Ate. EPA mnta pubic comment on all of.
the alternatives evaluated in the FS and the pulu'iol abvemtmdescribedin EPA*s P*«-
posed Plan. ' • ••-•=•
EPA will host a pabtte Infonsatloanl meetta* «• Aaf«at3,90-at Ut+m. at tk»
Tynfsborough Hith School (located at SO Norm Road m Tyngstorouffa) to describe Ike
FS and the preferred aitemative and to answer quc9tk>u. Resuha.of the Phaac 111
Remedial Investigation also will be divnuvd at this meeting. EPA wffl boida HjivMPMk-
p«Mic comm«at period f rwa Aagwl 4 lhro«th Aafisl 34,- BfJ to provide'an opportHai-
ty for the pubbc to participate in the selection of a final cleanup plan. The pubbc is invited
to review the Proposed Plan, the RJ, and the FS (available at theinfonnationrenosiuiriei
bsted below) and to offer written of oral comment to EPA during the comment period.
EPA will hold a pobttc hearing
7)GasFbuiB«
8) CombastioB/M«
i Btu GM Recovery
9) No Action
Sediments
10) Excavation. On-siie Sobdification, and Dtspoctl
11) In-utu Capping
12) Excavation, Thermal / crauoa. and Disposal
13) Excavation. Off-site Scnrand Disposal
14) Excavation, Off-site Incineration, and Disposal
15) Excavation and On>si>:. Duposal
1C) No Action
EPA's preferred abcrutrfc b a three part pfew.
CTO lrt*4 ab«vc. Biological Treatment and Carbon Adsorption would entail extracts!*
shallow groundwater from th^ southwestern and eastern areas of the tandftD and tiweJMf
the groundwater, along with landfill kachate, in a treatment system aaing I
four treatment processes to remove organic compounds and metals: biological I
precipitation; carbon adsorption; and ion exchange. Treated groondwaia i
would be discharged to DunstabJe Brook. In addition, a program would be i
to monitor deep bedrock groundwater to ensure that it docs not pose a risk to driakmc
wdb.
Incineration of landfill gas emissions would entail collecting all emissions from the
•t
-------
. ... .• ,.«uc ... .-j cva.uaico ave alternatives to acaress leachate and groundwater con-
tamination, four alternatives to address contamination in landfill gas emissions, and
seven alternatives to address contamination in off-site sediments. These alternatives are:
Leachate and Groundwater
1) Biological Treatment and Carbon Adsorption
2) Carbon Adsorption
3) Air Stripping and Carbon Adsorption
. 4) Off-Site Treatment
5) No Action Landfill Gas EmMins
6) Incineration
7) Gas Flaring
8) Combustion/Medium Bto Gas Recovery
9) No Action
10) Excavation. Go-site Solidification, and Disposal
11) la-titu Capping
12) Excavation. Thermal Aeration, and Disposal
13) Excavation, Off -rite Solidification, and Disposal
14) Excavation, Off-site Incineration, and Disposal
IS) Excavation and On-sitt Disposal
16) No Action
EPA'i pufurtd alfci Mli n h • three part pin, compose* of «h«r»«tfrei fl, K.
no acted ab*v«. Biological Treatment and Carbon Adsorption would entail extracting
shallow groundwater from the southwestern and eastern areas of the landfill and treating
the groundwater, along whh landfill leachate, in a treatment system using the following
four treatment processes to remove organic compounds and metals: biological treatment;
precipitation; carbon adsorption; and ion exchange. Treated groundwater and leachate
would be discharged to Dunstabie Brook. In addition, a program would be implemented
to monitor deep bedrock groundwater to ensure that it does not pose a risk to drinking
weib.
Incineration of landfill gas emissions would email collecting all emissions from the
landfill gas vents and tearing them in an on-sitc incinerator. Excavation, solidification,
and disposal of sediments would entail excavating approximately 500 cubic yards of con-
taminated sediments from Dunstabie Brook and from a tributary that flows into
Dunstabie Brook from the western side of the landfill. The excavated sediments would be
solidified in an on-site facility *nd l^en disposed underneath the landfill cap that EPA will
i constructing at the site in 1989. The preferred alternative is described in detail in
|A's Proposed Plan.
• Proposed Plan, the Phase III FS, and other site-related documents are available
for review at the following information repositories:
Tyngsborough Board of Health LJttlefield Publk Library
Tyngsborough Town Hall 22 2 Middlesex Road
10 Kendall Road • .Tyngsborough, MA 01 879
Tyngsborough, MA 01 879 (508)649-7361
(508)649-7441 . Tues.andFri.: 9:00a.m. -4:00p.m.
Moo-Fri: 9tfOa.m. - 12 Wed.: 9:00 a.m. -9:00 p.m.
l.*00pja. -4:00p.m. Thun.: 9:00 a.m. -4:00p.m.
EPARecordsCemer 7:00 p.m. -9:00 p.m.
90 Canal Street. 1st Floor
Boston, MA 02108
(617)573-5729
Mon.-Fri.:8:30a.m.-l:OOp.m..2:00-5:OOp.m.
In addition, EPA has compiled the Administrative Record for the Charles George site.
The Administrative Record contains all of the documents and reports prepared to date
thai have been and will be used by EPA and the Massachusetts Department of En-
vironmental Quality Engineering a the basis for selecting cleanup remedies for the site.
The Administrative Record will be available for public review by August 1 , 1988 at the Li t-
Uefield Publk Library and the EPA Records Center (addresses listed above}.
If you would tike to comment in writing on the FS or EPA's Proposed Plan, please mail
your written comments f postmarked no later than August 24) to:
David Dickerson, Remedial Project Manager
U.S. Environmental Protection Agency, Region I
Waste Management Division
J.F.K. Federal i^.JingfHR
Boston. MA 02203-22 11
(617)573-5735
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APPENDIX C
Daniel S. Greeriaur.
uc^^/7^c^^a^ecuu
C
^icfi, fy -iJTyT^T-^fly-f-f
ue
u nanjeewia,
. 0*1 C8
Sept. 28. 1988
Michael R. Deiand
Regional Administrator
U.S., E.P.A.
JFK Federal Building
Boston. .MA 02203
Dear Mr. Deland;
Re: Tyngsboro-Concurrence with
for Charles George Landfill
Federal Superfund Site
The Department of Environmental Quality Engineering (the Department) has
reviewed the preferred remedial action alternative recommended by EPA for mana-
gement of off-site migration at the Charles George Landfill federal Superfund
site. The Department concurs with the selection of the preferred alternative
for the site.
The Department has evaluated EPA's preferred alternative for consistency
with M.G.L. Chapter 22E as amended in November. 1986. and the Massachusetts
Contingency Plan (MCP). The preferred alternative addresses the final two pha-
ses or operable units for clean-up at the site and includes the following three
components :
(2) combined treatment of landfill leachate and groundwater.
(2) incineration of landfill gas emissions, and
(3) excavation, solidification, and disposal of sediaents.
The Department has determined that the preferred alternative is not a permanent
remedy as defined in M.G.L. c. 21E and the MCP due to the exceedance of the
Total Site Carcinogenic Risk Limits. The preferred remedy, however, would be
considered a temporary solution if institutional controls are used to prevent
future use of contaminated groundwater. The Department therefore recommends
that institutional controls be used to prevent future use of the contaminated
groundwater.
As the preferred remedy is a temporary solution, the MC? requires that a
Final Remedial Response Plan (FRRP) be prepared for the identification and deve-
lopment of a feasible permanent solution. As part of the FRRP. the Department
anticipates evaluating the effectiveness of both the groundwater monitoring
program and the institutional control provisions. These programs may. in time,
-------
Michael R. Deland
September 28. 1988
Page Two
indicate the need for further remedial action or that a permanent solution has
been achieved if the Total Site Risks are demonstrated to meet the MC? risk
liaits.
The proposed remedy appears to neet ail ARARs. The Department will con-
tinue to evaluate the ARARs as remedial design progresses and during implemen-
tation and operation of the remedy.
The Dep^rtaent looks forward to working with you in implementing the pre-
ferred alternative. If you have any questions or require additional infor-
mation, please contact Dale Young at 292-5785.
Very truly yours.
Daniel S. Greenbaum. Commissione:
Department of Environmental
Quality Engineering
DY,'sc:lgw
Edmond 3eno;.t. DEQE/CKO
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