PB96-963125
EPA/ESD/R01-96/126
March 1997
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Pinette's Salvage Yard Superfund Site,
Washburn, ME
6/20/1996
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DECLARATION FOR THE EXPLANATION OP
SIGNIFICANT DIFFERENCES
SITE NAME AND LOfATTOM
Pinette's Salvage Yard Superfund Site
Washburn, Maine
STATEMENT OF PURPOSE
This decision document sets forth the basis for the determination
to issue the attached Explanation of Significant Differences
(ESD) for the Pinette's Salvage Yard Superfund Site in Washburn,
Maine.
STATUTORY BASIS FOR ISSUANCE OF ESD
Section 117(c) of the Comprehensive Environmental Response,
Compensation and Liability Act (CERCLA) requires that, if any
remedial or enforcement action is taken under Section 106 of
CERCLA after adoption of a final remedial action plan, and if
such action differs in any significant respects from the final
plan (i.e., scope, performance or cost), the United States
Environmental Protection Agency (EPA) shall publish an
explanation of the significant differences and the reasons such
changes were made. Current EPA guidance (OSWER Directive 9355.3-
02) further provides that issuance of an ESD is appropriate where
the Agency determines the need for changes to the ROD which are
significant but which do not fundamentally alter the overall
remedy. In the present case, because the required adjustments to
the ROD do not fundamentally alter the selected remedy for the
Site, this ESD is being issued properly.
In accordance with Section 117(d) of CERCLA, this ESD will become
part of the Administrative Record which is available for public
review at both the EPA Region I Record Center in Boston/
Massachusetts and the Washburn Town Hall in Washburn, Maine.
DECLARATION
For the foregoing reasons, by my signature below, I approve the
issuance of an Explanation of Significant Differences for the
Pinette's Salvage Yard Superfund Site in Washburn, Maine and the
changes stated therein.
.Date '^-Linda M. Murphy, Dir«
' Office of Site Remediation
and Restoration
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EXPLANATION OF SIGNIFICANT DIFFERENCES
PINETTE'S SALVAGE YARD SUPERFUND SITE
WASHBURN, MAINE
I. INTRODUCTION
A. Site Name and Location
Site Name: Pinette's Salvage Yard Superfund Site
Site Location: Washburn, Maine
B. Lead and Support Agencies
Lead Agency: United States Environmental Protection
Agency
Support Agency: Maine Department of Environmental
Protection
C. Legal Authority
Section 117(c) of the Comprehensive Environmental Response,
Compensation and Liability Act (CERCLA) requires that, if
any remedial or enforcement action is taken under Section
106 of CERCLA after adoption of a final remedial action
plan, and if such action differs in any significant respects
from the final plan, the United States Environmental
Protection Agency (EPA) shall publish an Explanation of the
Significant Differences and the reasons such changes were
made.
D. summary of Circumstances
On May 30, 1989 EPA issued a Record of Decision (ROD) for
the Pinette1^ Salvage Yard Superfund Site. The ROD included
requirements for source control and management of migration.
On June 2, 1993, the EPA amended the Source Control
component of the 1989 ROD by changing the remedy for
contaminated soil from on-site treatment and off-site
incineration to off-site land disposal and off-site
incineration. The ROD required active treatment of
groundwater as a component of the Management of Migration
(groundwater).
Since the issuance of the ROD and completion of the Source
Control remedy, the EPA has evaluated the new information
obtained during the remedial pre-design process, has re-
evaluated the administrative record information supporting
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the 1989 ROD, and has determined that active groundwater
treatment is no longer necessary. Accordingly, EPA is
issuing this Explanation of Significant Differences (ESD).
E. Administrative Record
In accordance with Section 117(d) of CERCLA, this ESD and
the new information obtained will become part of the
Administrative Record which is available for public review
at both the EPA Region I Record Center in Boston,
Massachusetts and the Washburn Town Hall in Washburn, Maine.
II. SUMMARY OF SITE HISTORY, CONTAMINATION PROBLEMS AND SELECTED
REMEDY
A. Site History
Pinette's Salvage Yard Site is situated on less than one
acre in the town of Washburn in Aroostook County, Maine.
Currently, the site is fenced and used as an automobile and
scrap metal salvage' yard. About 15 persons live within a \
mile radius of the site. These persons rely on private
wells for drinking water.
In June 1979, three electrical transformers were reportedly
brought on-site where they ruptured and released about 900
to 1,000 gallons of dielectric fluid containing
polychlorinated biphenyls (PCBs) and volatile organic
compounds (VOCs) directly onto the ground.
From October 4, 1983 to November 4, 1983, under emergency
removal authority, the EPA removed about 1,000 tons of
contaminated soil and debris. The excavated soils were
transported to a. hazardous waste landfill in New York. In
1994, under remedial authority, the EPA completed the Source
Control Remedial Action during which approximately 1,000
tons of contaminated soil were excavated and incinerated at
an off-site incinerator and approximately 5,000 tons of
contaminated soil were excavated and disposed of at an off-
site hazardous waste landfill.
B. Remedial investigation/Feasibility Study (RI/FS)
An investigation into the nature and extent of contamination
at the Site was conducted from 1987 to 1989. The Remedial
Investigation was performed to characterize the geology,
hydrogeology, and distribution of contaminants in soil,
groundwater, surface water, and sediments at the Site. The
Remedial Investigation and Feasibility Study dated March
1989 are included in the Administrative Record.
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Based on the Feasibility Study, EPA proposed a remedy called
the "preferred alternative" for the Site in a Proposed Plan
dated March 1989.
C. Summary of the 1989 selected Remedy
On May 30, 1989, the EPA signed a Record of Decision (ROD)
for the Pinette's Salvage Yard Superfund Site. The selected
cleanup approach for the Site includes two primary
components: Source Control and Management of Migration.
Only the Management of Migration component is affected by
this BSD and is summarized below. The Source Control
component (as amended in June 1993) has been completed. The
Source Control component of the 1989 ROD originally called
for on-site solvent extraction treatment and off-site
incineration of contaminated soils, but was amended in 1993
for 'off-site land disposal and off-site incineration. Refer
to the 1989 Record of Decision and the 1993 ROD Amendment
for a complete description of the Source Control and
Management of Migration components.
The Management of Migration component of the 1989 ROD
required that contaminated groundwater containing
concentrations above the following target cleanup goals be
extracted from the ground and treated on site using
filtration and carbon adsorption.
The 1989 Target Cleanup Goals in groundwater were as
follows:
Polychlorinated biphenyls (PCBs): .5 ppb
Benzene: 5 ppb
1,4 - Dichlorobenzene: 27 ppb
Chlorobenzene: 47 ppb
1,2,4 Trichlorobenzene: 680 ppb
Chloromethane: 10 ppb
Lead: 5 ppb
The target cleanup goal for lead was based on a proposed
maximum contaminate level (proposed MCL) for drinking water
which was never adopted by the EPA. This BSD adjusts the
site target cleanup goal for lead to the current nationally
accepted MCL of 15 ppb.
The objectives of the Management of Migration component of
the 1989 ROD were l) to reduce the potential for off-site
migration of PCBs by reducing the concentration of
associated VOCs that facilitate the transport of PCBs, 2) to
prevent persons from ingesting contaminated water from the
site, and 3) conduct five year reviews. The 1989 ROD did
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not require restoration of the "groundwater to drinking water
quality, but rather explicitly recognized the technical
impracticability of reducing the PCS contamination to drinking
water quality. In recognizing this treatment limitation, the
1989 ROD waived the legal requirement of achieving the State of
Maine Maximum Exposure Guideline (ME MEG) of 0.5 ppb for PCBs in
groundwater beneath the site.
The 1989 ROD determined that treatment of groundwater was,
however, warranted to reduce the mobility of the PCBs by
reducing the concentrations of certain volatile organic
compounds. Volatile organic compounds, including
trichlorobenzene, were typically used in transformers to
decrease the viscosity of PCBs which are naturally waxy and
not very mobile. While VOCs were never found in residential
wells at levels that would pose the need for remedial
action, it was believed that by reducing the concentration
of these carrier VOCs in groundwater, the potential for off-
site migration of PCBs would be sufficiently prevented.
0. Source Control Remedial1Action
In May 1991, EPA initiated source control remedial
activities at the site. These activities included removing
junk cars, erecting a fence around the perimeter of the
site, excavating, dewatering, installing concrete pads on
large portions of the site, and removing soils contaminated
with PCBs. In 1993, after unsuccessful attempts to use the
selected on-site solvent extraction treatment technology,
the EPA issued an amendment to the source control remedy to
dispose of contaminated soil at off-site facilities.
Depending on the concentrations of PCBs, the contaminated
soils were disposed of at either a TSCA landfill or TSCA
incinerator. The source control remedial action work was
completed in 1993, and grading and revegetation of the site
were completed in 1994.
E. Management of Migration Pre-design Studies
In August 1990 and December 1991, EPA conducted further
groundwater sampling at the site. Analytical results of
this sampling in comparison to earlier rounds of sampling
conducted in 1987 and 1988 indicated that VOC contamination
of the groundwater was decreasing over time. To understand
the impact the Source Control remedial activities were
having on groundwater contamination, -EPA conducted further
sampling of monitoring wells in March 1993, July 1993,
January 1994, April 1994, October 1994, April 1995, July
1995, and October 1995.
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Residential wells were sampled yearly: November 1987, June
1988, August 1990, August/December 1991, March 1993, April
1994, and April 1995. The two residential wells farthest
from the site were removed from the sampling program after
the August 1991 sampling round because EPA determined that
the chemicals detected from these wells during previous
sampling rounds indicated that they were not at levels of
health concern and these residential wells were located a
great distance away from the Site and would not be impacted
by the site. Groundwater flow direction is to the
southeast. All of the Residential wells are located to the
northeast and southwest of the site.
III. DESCRIPTION OF SIGNIFICANT DIFFERENCES
A. Additional Extraction and Treatment of Groundwater not
Warranted
Groundwater sampling data collected during the Management of
Migration Pre-design studies following the completion of the
source control remedy indicates that the concentrations of
VOCs have decreased to below or near the target cleanup
goals established in the 1989 ROD. Decrease in VOC levels
are attributable to the natural attenuation/degradation of
contaminants, to the extraction and treatment of over one
million gallons of contaminated groundwater during source
control remedial activities, and to improved groundwater
sampling techniques.
Unfiltered groundwater samples were analyzed for VOCs, semi-
volatile organics, pesticides, PCBs, metals and total
dissolved solids. Filtered groundwater samples were
analyzed for PCBs and metals. Beginning with the April 1995
round, EPA began using low flow sampling procedures. Low
flow sampling is considered by EPA Region I as the optimal
groundwater sampling method for evaluating mobility of
contaminants in groundwater and is also considered most
representative of human exposure through ingestion of
groundwater.
In monitoring wells, the maximum concentration of lead
detected in unfiltered samples since EPA began using low
flow sampling in 1995 has been 14.5 ppb, below the target
cleanup goal (as amended by this BSD) of 15 ppb. The
maximum concentration of PCBs in unfi-ltered monitoring well
•samples detected since the low flow sampling began is 8.5
ppb, which is still above the target cleanup goal of 0.5
ppb. VOCs for which there are target cleanup goals
established for the site have not been detected in
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unfiltered samples above MCLs since low flow sampling began.
In residential wells, the maximum level of lead detected in
unfiltered groundwater sample was at 7.1 in April 1995.
There is no reason to believe that this lead can be
attributed to the transformer spill at the site. None of
the residential wells are downgradient of the site. PCBs
have never been detected in residential wells. VOCs for
which target cleanup goals have been established for the
site have not been detected in unfiltered samples above MCLs
in residential wells.
The results and evaluation of the data are presented in
"Management of Migration, Summary of Environmental Data and
Evaluation Report, June 1996." This report is included in
the Administrative Record.
The monitoring results demonstrate that,the primary
objective of the Management of Migration component of the
ROD has been achieved—PCS migration has been sufficiently
reduced. The 1989 ROD required active groundwater treatment
to reduce the concentration of VOCs to their cleanup goals
as a means of reducing the migration of PCBs. The
concentrations of VOCs are already below their cleanup
goals. Furthermore, the migration of PCBs has been
sufficiently reduced; downgradient wells have not shown any
contamination. Consequently, there is no need to actively
treat the groundwater.
B. Adjusted Target Cleanup Goals
In the 1989 ROD, the EPA established a cleanup goal for lead
based on a proposed maximum contaminate level (proposed MCL)
for drinking water which was never adopted by the EPA. This
BSD adjusts the site target cleanup goal for lead to the
current nationally accepted MCL of 15 ppb. None of the on-
site monitoring wells or off-site residential wells have
lead levels above the 15 ppb level established for drinking
water.
IV. SUMMARY OP FUTURE RESPONSE ACTIONS
A. Institutional Controls
As foreseen by the 1989 ROD and based on an evaluation of
the 1995 low flow sampling data, the groundwater is still
contaminated with concentrations of contaminants which would
pose an unacceptable risk if ingested. Exceedances of MCLs
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for PCBs, bis(2-ethylhexyl)phthalate, antimony, and chromium
have been detected in unfiltered groundwater samples from
on-site monitoring wells. Additionally, the following VOCs
were detected, although below MCLs, in unfiltered samples
from on-site monitoring wells: chlorobenzene, 1,3-
dichlorobenzene, 1,4-dichlorobenzene, 1,2-dichlorobenzene,
1,2,4-trichlorobenzene, 1,2,3-trichlorobenzene, benzene, and
xylene.
To prevent the ingestion and use of contaminated
groundwater, institutional controls (e.g., deed
restrictions) will be established to prevent the
installation of domestic wells on the site.
B. Five Year Reviews
Five year reviews of the site will be conducted to ensure
that the remedy remains protective. At a minimum,
groundwater samples will be collected from the monitoring
well network during these reviews. These five year reviews
will" determine whether the institutional controls are being
effective and enforced, whether residential wells should be
sampled, whether site conditions have changed with respect
to potential migration which would warrant a different
remedial approach, or whether the institutional controls can
be removed.
EPA requested the Agency for Toxic Substances and Disease
Registry (ATSDR) for a recommendation regarding future
residential well sampling. The ATSDR has reviewed the
environmental data and has concluded that contaminants
detected in groundwater samples from residential wells are
not at levels of public health concern. This is consistent
with earlier groundwater sampling of residential wells which
concluded that contaminants would not pose a health hazard
to those persons who use it on a daily basis. Furthermore,
site related contaminated groundwater does not flow'in the
direction of the domestic wells.
ATSDR does not see the need for further residential well
sampling but recommends that EPA continue to sample the on-
site monitoring wells. If conditions change at the Site,
ATSDR recommends that EPA reevaluate the need for sampling
residential wells.
V. SUPPORT AGENCY COMMENTS
The Maine DEP acknowledges that the Maine DEP has had an
opportunity for review and comment and concurs with this ESD-
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(Attachment 1).
VI. STATUTORY DETERMINATIONS
Considering the adjustment to the selected remedy set forth
in the 1989 ROD and as described in this ESD, the EPA
believes that the remedy remains protective of human health
and the environment, complies with all Federal and State
requirements that are applicable or relevant and appropriate
to this remedial action and is cost effective.
VI. PUBLIC PARTICIPATION
In accordance with Section 117(d) of CERCLA, this ESD will
become part of the Administrative Record which is available
for public review at both the EPA Region I Record Center in
Boston, Massachusetts and the Washburn Town Hall in
Washburn, Maine.
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FIGURE 1 - SITE LOCATION MAP
FIGURE 2 - SITE FEATURES MAP
ATTACHMENT 1 - STATE CONCURRENCE LETTER
8
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FIGURE 1
SITE LOCATION MAP
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REFERENCE:
U.S.G.S. 7.5 Minute Topographic Quadrangle Map
Washbum, Maine, 1984. SCALE 1:24,000
USEPA ARCS I PROGRAM
CONTRACT NO. -68-W9-0034
PINETTE'S SALVAGE YARD SITE
SITE LOCATION MAP
FIGURE1
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FIGURE 2
SITE FEATURES MAP
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ATTACHMENT 1
STATE OF MAINE CONCURRENCE LETTER
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STATE OF MAINE
DEPARTMENT OF ENVIRONMENTAL PROTECTION
ANGUS S KING Jfl HOWARD 0 SULLIVAN
JUN 1»
June 10, 1996
John DeVillars
Regional Administrator
U.S. Environmental Protection Agency
JFK Building (HBT)
Boston MA 02203-2211
Subject: State Concurrence of ESD for Pinette's Salvage Yard Superfund Site
Dear Mr. DeVillars:
The Maine Department of Environmental Protection (MDEP) has reviewed the May 30,
1996 Draft Explanation of Significant Differences (ESD) with regard to the Management
of Migration for Pinette's Salvage Yard Superfund Site in Washbum, Maine.
Groundwater samples were collected and analyzed during the Management of Migration
following the completion of the Source Control remedial activities. The groundwater
sampling data document a decrease in the concentration levels of Volatile Organic
Compounds (VOC's) that facilitate the transport of PCB's to within target cleanup goals
established in the 1989 Record of Decision (ROD). Decrease in the VOC levels are
attributable to the natural attenuation/degradation of contaminants, to the extraction and
treatment by carbon adsorption of over one million gallons of water during Source
Control remedial activities, and to improved groundwater sampling techniques. It was
not the objective of the Management of Migration component of the 1989 ROD to restore
groundwater to drinking water quality because it was technically impracticable to remove
the PCBs. The concentration of PCBs in groundwater have decreased following Source
Control remedial activities but still remain above the Maine Maximum Exposure
Guideline (MEG) of 0.5 ppb.
Since EPA began using low flow sampling techniques in 1995, the maximum
concentration of lead detected in monitoring wells was 14.5 ppb which is below the
federal Maximum Contaminant Level (MCL) and the Maine Maximum Exposure
Guideline (MEG) of 20 ppb for lead.
The Department concurs with the following changes to The Management of Migration
components of the 1989 Record of Decision (ROD).
Serving Maine People cV Protecting Their Environment
AUGUSTA PORTUWD 8ANGOB PHESOUE ISLH
17 STATE HOUSE STATION 3i2CA*coflOAO KMHOGAMHOAO 1335 CENTRAL Crave, SKYMVAY PARK
AUGUSTA MAINE 0*113-0077 PORTLAND ME 04103 BAWQOJI ME 04401 PHESOUS ISLE. ME 04769
(JOT) 2B7.76M FAX (207) 2B7-7S28 (JOT) 322-«300 FAX (207) E22-S303 (207) 941-4S70 FAX <»7) 941-4J84 (207) 76*-O4T7 FAX 1207) 784.1507
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A. Removing the requirement for further extraction and treatment of contaminated
groundwater. Further treatment is not warranted to reduce the potential of PCB
migration.
B. Adjusting the site cleanup goal for lead in groundwater from 5 ppb to 15 ppb.
The 19X9 ROD selected 5 ppb based on an EPA proposal to change the MCL for lead
from 15 ppb to 5 ppb. The proposal was never adopted and 15 ppb remains the current
MCL.
Maine DEP accepts 15 ppb as the cleanup level for lead in that it is more restrictive than
the MEG of 20 ppb for lead.
Furthermore, it is the understanding of the Department, that EPA will conduct a review
every five years following the remedial action to ensure that the remedy continues to
provide adequate protection of human health and the environment.
The Department shall receive the analytical results reports from the EPA contractor and
will be awarded reasonable opportunity to review monitoring plans and participate in any
meetings regarding this site.
Institutional controls such as deed restrictions will be implemented to prevent ingestion
and use of PCB contaminated water from the installation of drinking water wells on the
site.
The State will not be responsible for any future Operation and Maintenance at Pinette's
Salvage Yard Superfund Site.
The Department in partnership with EPA is pleased to have cleaned up this Superfund
site.
Sincerely,
>v
Edward O. SuMvan
cc: MarkHyland
Denise Messier
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