Superfund Record of Decision Loring Air Force Base Operable Unit 2A Limestone ME


                                    EPA/ROD/R01-96/120
                                    1996
EPA Superfund
     Record of Decision:
     LORING AIR FORCE BASE
     EPA ID: ME9570024522
     OU14
     LIMESTONE, ME
     03/31/1996

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                                         FINAL

                            OPERABLE UNIT 2A (OU 2A)
                              RECORD OF DECISION

                                   MARCH 1996



                         Installation Restoration Program
                           Loring Air Force Base, Maine

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                               TABIiE OF CONTENTS


Section                               Title                               Page  No.

DECLARATION FOR THE RECORD OF DECISION  	D-l

1.0  SITE NAME, LOCATION, AND DESCRIPTION   	1-1

2 . 0  SITE HISTORY AND ENFORCEMENT ACTIVITIES   	2-1
       2 .1  LAND USE AND RESPONSE HISTORY   	2-1
       2.2  INVESTIGATION AND RESPONSE HISTORY   	2-4

3.0  COMMUNITY PARTICIPATION  	3-1

4 . 0  SCOPE AND ROLE OF RESPONSE ACTION  	4-1

5 . 0  SUMMARY OF SITE CHARACTERISTICS  	5-1
       5 .1  LANDFILL 1   	5-1
       5 . 2  COAL ASH PILE  	5-2

6 . 0  SUMMARY OF SITE RISKS  	6-1
       6.1  SUMMARY OF RISKS AT LANDFILL 1   	6-2
       6. 2  SUMMARY OF RISKS AT THE CAP  	6-10

7 . 0  DESCRIPTION OF THE NO ACTION ALTERNATIVE   	7-1

8 . 0  DOCUMENTATION OF NO SIGNIFICANT CHANGES   	8-1

9 . 0  STATE ROLE  	9-1

GLOSSARY OF ACRONYMS AND ABBREVIATIONS

REFERENCES

APPENDICES
APPENDIX A    -    TRANSCRIPT OF PUBLIC MEETING
APPENDIX B    -    RESPONSIVENESS SUMMARY
APPENDIX C    -    MEDEP CONCURRENCE WITH NO ACTION REMEDY

                                 LIST OF TABLES


Table                             Title                                      Page No.

1     Human Health and Ecological Contaminants  of Concern from  1990  to
      1991 RI Sampling Data  	6-4
2     Human Health Risk Assessment Exposure Parameters   	6-7
3     Total Site Risks Under Current Land Use   	6-8
4     Summary of Ecological Risk Assessment for Terrestrial  Organisms  	6-9
5     Summary of Potential contaminants in Surface Soil   	6-12
6     Human Health Risk Assessment Exposure Parameters   	6-15
7     Summary of Human Health Risk  	6-16
8     Summary of Ecological Risk Assessment for Terrestrial  Organisms   	6-17

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                   DECLARATION FOR THE RECORD OF DECISION

SITE NAME AND LOCATION

Loring Air Force Base  (LAFB) Operable Unit  (OU) 2A consists of source control  (surface and subsurface
soils, and source areas) at Landfill 1 and the Coal Ash Pile  (CAP).

STATEMENT OF BASIS AND PURPOSE

This decision document was developed in accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act  (CERCLA) of 1980, as amended by the Superfund Amendments and
Reauthorization Act  (SARA) of 1986, and to the extent practicable, the National Oil and Hazardous
Substance Pollution Contingency Plan (NCP)  (USEPA, 1990).  It is based on the Administrative Record for
the site, which was developed in accordance with Section 113(k) of CERCLA and is available for public
review at the Air Force Base Closure Agency, 5100 Texas Road, Limestone, Maine.  It presents the selected
No Action under CERCLA
decision for OU 2A at LAFB.

The State of Maine Department of Environmental Protection  (MEDEP) concurs with the No Action under CERCLA
remedy for OU 2A.  In a separate action which is not part of this Record of Decision  (ROD), the U.S. Air
Force has undertaken a time-critical removal action at the CAP consistent with the criteria set forth
under Section 300.415  (b)(2) of the NCP.  The   objectives established in the "Time Critical Removal
Action Memorandum, Operable Unit 2A, Coal Ash Pile, "  (Air Force Center for  Environmental Excellence
[AFCEE]  1994), have been met as a result of the removal action and, therefore, no further action under
CERCLA is necessary at the CAP.

DESCRIPTION OF THE SELECTED REMEDY

The U.S. Air Force and U.S. Environmental Protection Agency  (USEPA), with concurrence of the MEDEP, have
determined that no action under CERCLA is necessary to address contamination at OU 2A, which comprises
Landfill 1 and the CAP.  It is recommended that Landfill 1 be classified as a construction debris
landfill with no CERCLA reguirement for action.



SITE NAME AND LOCATION

Loring Air Force Base  (LAFB) Operable Unit  (OU) 2A consists of source control  (surface and subsurface
soils,and source areas) at Landfill 1 and the Coal Ash Pile  (CAP).

STATEMENT OF BASIS AND PURPOSE

This decision document was developed in accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act  (CERCLA) of 1980, as amended by the Superfund Amendments and
Reauthorization Act  (SARA) of 1986, and to the extent practicable, the National Oil and Hazardous
Substance Pollution Contingency Plan (NCP)  (USEPA, 1990).  It is based on the Administrative Record for
the site, which was developed in accordance with Section 113(k) of CERCLA and is available for public
review at the Air Force Base Closure Agency, 5100 Texas Road, Limestone, Maine.  It presents the selected
No Action under CERCLA decision for OU 2A at LAFB.

The State of Maine Department of Environmental Protection  (MEDEP) concurs with the No Action under CERCLA
remedy for OU 2A.  In a separate action which is not part of this Record of Decision  (ROD), the U.S. Air
Force has undertaken a time-critical removal action at the CAP consistent with the criteria set forth
under Section 300.415  (b)(2) of the NCP.  The   objectives established in the "Time Critical Removal
Action Memorandum.  Operable Unit 2A, Coal Ash Pile, "  (Air Force Center for  Environmental Excellence
[AFCEE]  1994), have been met as a result of the removal action and, therefore, no further action under
CERCLA is necessary at the CAP.

DESCRIPTION OF THE SELECTED REMEDY

The U.S. Air Force and U.S. Environmental Protection Agency  (USEPA), with concurrence of the MEDEP, have
determined that no action under CERCLA is necessary to address contamination at OU 2A, which comprises
Landfill 1 and the CAP.  It is recommended that Landfill 1 be classified as a construction debris
landfill with no CERCLA reguirement for action.

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Completion of the time critical removal action of the coal ash at the CAP constitutes closure of the
source at the CAP.  The surface water and groundwater media at the OU 2A sites will be addressed in OU 13
and OU 4, respectively.

DECLARATION

The U.S. Air Force and USEPA, with concurrence of the MEDEP, have determined that no remedial action
under CERCLA is necessary at OU 2A.  As this is a decision for No Action under CERCLA, the statutory
requirements of CERCLA Section 121 for remedial actions are not applicable, and no five-year review will
be undertaken.

Department of the Air Force

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1.0 SITE NAME, LOCATION, AND DESCRIPTION

Loring Air Force Base (LAFB) is a National Priorities List (NPL) site. There are currently several area
of concern within LAFB that are under investigation. The area of concern at LAFB have been organized
into Operable Units (OUs) for investigation and remediation purposes. This Record of Decision (ROD)
relates to the Source Control Remedial Action for OU 2A, which is composed of Landfill 1 and Coal Ash
Pile (CAP) (Figure 1). The CAP includes the Coal Ash Disposal Area (CADA) , the Paint Can Disposal Area
(PCDA) , and the Drum Disposal Area (DDA) .

LAFB, in northeastern Maine, is bordered on the south and east by the Town of Limestone, on the north by
the towns of Caswell and Connor, and on the east by the City of Caribou. The base is approximately
three miles west of the United States/Canadian border and covers approximately 9,00 acres. Base
operations gradually decreased until base closure in September 1994.

Because of its primary mission, LAFB personnel were engaged in various operations, a number of which
reguired the use, handling, storage, or disposal of hazardous materials and substances. In the past,
these materials entered the environment through accidental spills, leaks in supply piping, landfilling
operations, burning of liguid wastes during fire-training exercises, and the cumulative effects of
operations conducted at the base's flightline and industrial areas. As part of the Department of
Defense's (DOD) Installation Restoration Program (IRP), the Air Force initiated activities to identify,
evaluate, and remediate former disposal or spill sites containing hazardous substances.

Since initiation of the IRP, the base has been placed on the U.S. Environmental Protection Agency's
(USEPA's) NPL of sites and will be remediated according to the Federal Facility Agreement (FFA), an
agreement under Section 120 of CERCLA signed by the Air Force, the USEPA, and the Maine Department of
Environmental Protection (MEDEP) on January 30, 1991 as amended.

The area which was comprised primarily of coal ash is referred to as the CADA. Construction and other
debris also were disposed of in this area. The types of debris found are described in the Final

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Remedial Investigation (RI) report (Advanced Sciences, Inc.[ASI], 1995), and consist primarily of coal
ash from the Base heating plant. In order to mitigate and prevent the release or threatened release of
hazardous substances, particularly polychlorinated biphenyls (PCBs) and polynuclear aromatic hydrocarbons
(PAHs), into the environment, removal actions began at the CAP site during the week of August 22, 1994
and ended the week of October 3, 1994. Approximately 140,000 cubic yards of coal ash were removed from
the CAP and transported to Landfill 2 and 3 for use as subgrade fill for construction of the landfill
caps as the remedial action for OU 2 (AFCEE, 1995). In addition approximately 44,000 cubic yards of
contaminated soil and concrete rubble were removed from the PCDA and DBA and incorporated into the
subgrade for capping Landfill 3 (AFCEE, 1996). The "Time Critical Removal Action Memorandum, Operable
Unit 2A, Coal Ash Pile Site," (AFCEE, 1994), the "Remedial Action Report/Project Closeout Report, OU2A,
OU2, OU6, OU7, and Other Sites" (AFCEE, 1995), and the "Remedial Action Report/Project Closeout Report
for the PCDA and DBA" (AFCEE, 1996) document the decision to perform the removal action. Removal of the
contaminated CAP soil and incorporation of this soil into the subgrade for capping Landfills 2 and 3 is
consistent with removal action criteria described in the National Contingency Plan (NCP), which describes
capping as an acceptable removal action for contaminated soil to reduce migration of hazardous
substances.

2.2 INVESTIGATION AND RESPONSE HISTORY

The investigation process began at LAFB in 1983 as part of the DOD IRP process, but was revised in 1988
in favor of a process that more closely followed the NCP used by the USEPA. Investigations performed to
date include a 1983 Preliminary Assessment (CH2M Hill, 1984) to investigate records of past activities
at LAFB. Unconfirmed guantities of hazardous substances were suspected of being buried at Landfill 1.
There was no record of activities at the CAP.

A Site Investigation was initiated in June 1985 to confirm the presence or absence of contaminants at
Landfill 1. A final report was issued in 1988 (R.F. Weston, Inc., 1988), which reported demolition
debris, primarily concrete, asphalt, lumber, and metal scrap was visible at scattered locations.
Exploratory borings and test pits identified the area of landfilling activities. No industrial or
hazardous waste was observed. The final report concluded that analytical results indicated no
significant contamination in groundwater or surface water. The only reported parameter identified as
contamination was a single sample of elevated chemical oxygen demand from one surface water location that
was explained as the result of natural decay of organic materials.

In addition, RI activities were conducted from 1988 through 1994. The purpose of the RI was to collect
data from environmental media at Landfill 1 and to evaluate human health and ecological risk at the site.
Additional surface and subsurface soils, surface water, groundwater and sediment samples were collected.
Although a variety of contaminants (primarily pesticides and concentrations of inorganics above
background) were detected sporadically; no incremental risk was identified relative to site-related
contaminants (ABB-ES, 1990; ASI, 1995). Surface water and sediment contamination will be addressed in OU
13.

LAFB was added to the NPL in February 1990. The Air Force entered into a FFA in 1991 with the USEPA and
MEDEP regarding the cleanup of environmental contamination at LAFB. The FFA was modified in December
1993 to address base closure-related issues, such as real property transfer and a revised schedule. The
FAA was modified in January 1995 to allow the Remedial Project Managers to make minor modifications to
the FFA, such as schedule adjustments or removal of petroleum-contaminated sites from the agreement.

Preliminary Remediation Goals (PRGs) were developed for OU 2A (ABB-ES, 1995a). Removal actions have
taken place at the CADA (AFCEE, 1995) and at the DBA and PCDA (AFCEE, 1996) . The removal actions were
consistent with the NCP, met the objectives of the Action Memorandum, and mitigated site risks.

A cover system consistent with the MEDDEP Solid Waste Regulations has been designed and is scheduled to
be constructed over Landfill 1 in 1996.

3.0 COMMUNITY PARTICIPATION

Throughout LAFB's history, the community has been active and involved to a high level in base activities.
The Air Force, USEPA, and MEDEP have kept the community and other interested parties apprised of LAFB
activities through informational meetings, fact sheets, press releases, public meetings, site tours, and
open houses, and Restoration Advisory Board (RAB) meetings. Membership of the RAB is composed of Air
Force, USEPA, MEDDEP, and local officials, and community representatives.

The LAFB community relations plan (CRP) was released in August 1991 and revised in May 1995. The CRP
outlined a program to address community concerns and keep citizens informed and involved during remedial
activities. The CRP can be found in the Administrative Record.

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On June 24, 1992, the Air Force made the Administrative Record available for public review.  The
Administrative Record is currently available for public review at the office of the Air Force Base
Conversion Agency Office, 5100 Texas Road, Limestone, Maine.

The Air Force published a notice and brief analysis of the OU 2A Proposed Plan with no further action
under CERCLA in the Bangor Daily News, the Aroostook Republican, the Fort Fairfield Review and the Star
Herald on January 10, 1996.

From January 16 through February 14, 1996, the Air Force held a 30-day public comment period to accept
public input on the information presented in the RI/Baseline Risk Assessment, Time Critical Removal
Memorandum, and the Proposed Plan, and on any other documents previously released to the public.  On
January 24, 1996, LAFB personnel and regulatory representatives held a public meeting to discuss the
removal action at the Coal Ash Pile and the Proposed Plan and to accept any oral comments.  A transcript
of this meeting is included in Appendix A, and the comments received during the comment period and the
Air Force's response to these comments are included in the Responsiveness Summary in Appendix B.

                     4.0 SCOPE AND ROIiE OF RESPONSE ACTION

The Air Force and USEPA have determined that no further CERCLA action is reguired at OU 2A.  Remaining
closure activities for Landfill 1 will be completed in accordance with Maine Solid Waste Management
Regulation.  Post-closure activities will be performed at Landfill 1 for a minimum of ten years.
Operation and maintenance  (O&M) reguirements are minimum.  Periodic site inspections and maintenance of
the cover  (e.g., mowing) are the primary components of O&M for Landfill 1.

The time critical removal action performed at the CAP, as described in the "Time Critical Removal Action
Memorandum, Operable Unit 2A, Coal Ash Pile Site," (AFCEE, 1994), provides closure at the CAP.

USEPA has the authority to revisit the No-Action under CERCLA decision even if the LAFB is removed from
the NPL.  This could occur if future conditions indicate that an unacceptable risk to human health or the
environment would result from exposure to contaminants at Landfill 1 or from the CAP.

                     5.0 SUMMARY OF SITE CHARACTERISTICS

Site investigations were conducted from June 1985 through 1994 to characterize the nature and
distribution of contaminants at OU 2A.  Detailed descriptions of the data are presented in the OU 2A
Final RI Report  (ASI, 1995).  The significant findings of these contamination assessments are summarized
in the following subsections.

5.1 LANDFILL 1

Investigations were conducted between 1985 and 1994 to assess if contamination was present, and if
present, characterize the nature and extent of surface soil contamination at Landfill 1.  Samples were
collected and analyzed for volatile organic compounds  (VOCs), semivolatile organic compounds  (SVOCs),
pesticides/PCBs, and Target Analyte List  (TAL)  inorganic elements/compounds using Contract Laboratory
Program (CLP)  methodology.

No clear contaminant sources were identified at Landfill 1, although the RI investigations at Landfill 1
have intermittently detected limited concentrations of inorganics, VOCs, SVOCs, pesticides, and the PCB
Aroclor-1260 in the various environmental media samples.

Inorganics were intermittently detected above background concentrations in surface soils, groundwater,
surface water, and sediment.  While several inorganics were detected slightly above background levels in
surface and subsurface soils, only cadmium, and lead were detected above background in more than one
sample from each media.  Inorganics in overburden and bedrock groundwater were evaluated at four selected
monitoring wells.  The evaluation was conducted in accordance with the consensus statement, "Inorganic
Contaminants in Overburden Groundwater", approved by the Air Force, USEPA and MEDEP in August 1995 for OU
12 and OU 13.   No inorganic contaminants of concern were found at LF-1.  Inorganics were the only group
of analytes detected above background concentrations in surface water.  However, these inorganics are not
uncommon to natural geologic systems similar to those found at LAFB.

VOCs and SVOCs were not detected in significant guantities in any media.  No VOCs were detected in
surface soils or surface water.  VOCs detected in subsurface soils were below Contract Reguired
Quantitation Limits  (CRQLs).  The limited VOCs detected in groundwater samples were also below CRQLs.
Several SVOCs were detected above CRQLs in surface soil,  while SVOCs were not detected above CRQLs in
subsurface soil.  No SVOCs were detected above CRQls in groundwater. No SVOCs were detected in surface
water or sediment samples.

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Pesticides were detected at concentrations less than background in surface and shallow subsurface soils
within the landfill and adjacent surface disposal areas. PCBs were detected at low concentrations in
surface and shallow subsurface soils but were not evaluated in the risk assessment because the risk
screening indicated that associated risks were relatively insignificant. Pesticides and PCBs were also
infreguently detected. Pesticides and PCBs were detected above background in sediments from Green Pond.
The presence of pesticides (DDT) is consistent with the widespread historical usage of the pesticide in
this area prior to the ban on its use. Pesticides and PCBs are not present in groundwater or surface
water.

The groundwater and surface water investigations have not been completed at this time; these
investigations will be evaluated separately in the OU 4 and OU 13 RI reports. Surface water and sediment
contamination will be addressed in OU 13.

5.2 COAL ASH PILE

Between 1991 and 1993, surface and subsurface soil/waste sample were collected and analyzed from the CAP
site. In general, analytical data indicate surface soil/waste contained more inorganics, SVOCs, and
pesticides than subsurface soil/waste.

Inorganics detected substantially above background levels in surface soils included barium, copper, iron,
lead, and zinc. Inorganics that slightly exceeded the background levels in subsurface soils include
beryllium, cadmium, calcium, cyanide, and selenium. Lead and zinc were detected in two CAP site borings
at concentrations well above background levels.

The only VOC detected was acetone, which was found in surface and subsurface soil/waste samples from the
CAP site.

Surface and subsurface samples collected from the CAP site contained SVOCs ranging from 44 to 14,000
micrograms per kilogram (]lg/kg) (benzo-(b)-fluoranthene), with the greatest number of detected SVOCs at
approximately of 10 feet below ground surface.

Pesticides were detected in subsurface soil/waste samples from the CAP site at concentrations ranging
from 0.18 to 52 jig/kg. There was no apparent vertical pattern of distribution. Additionally, one PCB
(i.e., Aroclor-1260) was detected in five of the 12 surface soil samples, at concentrations ranging from
60 jig/kg to 43,000 jig/kg. Aroclor-1269 was also detected in subsurface soils, ranging in concentrations
from 20 to 75 jig/kg.

Monitoring wells have been installed and screened within the bedrock in the vicinity of the CAP site.
Groundwater samples were collected and analyzed for inorganics, VOCs, SVOCs, pesticides/PCBs, and
miscellaneous parameters. Results of these data are presented in the OU 4 RI report (ABB-ES, 1995b).

Surface water samples were collected from a wet area southeast of the CADA and from an area to the
northwest that holds water after rainfall. Samples collected were analyzed for inorganics, VOCs, SVOCs,
pesticides/PCBs, and miscellaneous parameters. Results of these data are presented in the OU 13 Interim
RI report (ABB-ES, 1994).

6.0 SUMMARY OF SITE RISKS

A risk assessment was conducted to estimate the probability and magnitude of potential adverse human
health and environmental effects from exposure to contaminants associated with surface and subsurface
soils at OU 2A. The risk assessments followed a four-step process:

• contaminant identification, which identified those hazardous substances that, given the
specifics of the site, were of significant concern;

• exposure assessment, which identified actual or potential exposure pathways, characterized
the potentially exposed populations, and determined the extent of possible exposure;

• toxicity assessment, which considered the types and magnitude of adverse health effects
associated with exposure to hazardous substances; and

• risk characterization, which integrated the three earlier steps to summarize the potential
and actual risks posed by hazardous substances at the site, including carcinogenic and
non-carcinogenic risks.

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Excess lifetime cancer risks were determined for each exposure pathway by multiplying the exposure level
by the chemical-specific cancer slope factor. Cancer slope factors have been developed by USEPA from
epidemiological or animal studies to reflect a conservative "upper bound" of the risk posed by
potentially carcinogenic compounds. That is, the true risk is unlikely to be greater than the predicted
risk. The resulting risk estimates are expressed in scientific notation as a probability (e.g., 1x10-6
for 1/1,000,000) and indicate (using this example) that an individual has a one-in-a-million chance of
developing cancer as a result of site-related exposure over 70 years to the particular compound at the
stated concentration. Current USEPA practice considers carcinogenic risks to be additive when assessing
exposure to a mixture of hazardous substances.

The Hazard Quotient (HQ) was also calculated for each pathway as USEPA's measure of the potential for
noncarcinogenic effects. The HQ is calculated by dividing the exposure level by the reference dose (RfD)
or other suitable benchmark for noncarcinogenic health effects. RfDs have been developed by USEPA to
protect sensitive individuals over the course of a lifetime, and reflect a daily exposure level that is
likely to be without an appreciable risk of an adverse health effect. RfDs are derived from
epidemiological or animal studies and incorporate uncertainty factors to help ensure that adverse health
effects will not occur. The HQ is often expressed as a single value (e.g., 0.3) indicating the ratio of
the stated exposure to the RfD value (in this example, the exposure is approximately one-third of an
acceptable exposure level for the given compound). HQs are summed, resulting in a Hazard Index (HI) for
each pathway. If the HI is greater than 1, the predicted intake could potentially cause adverse health
effects. This determination is necessarily imprecise because the derivation of dose-response values
(i.e., RfDs) involves the use of multiple safety and uncertainty factors. In addition, the HQs for
individual compounds should be summed only if their target organs or mechanisms of action are identical.
Therefore, the potential for adverse effects from a mixture having an HI in excess of 1 must be assessed
on a case-by-case basis.

The results of the human health risk assessments are discussed below, followed by a discussion of the
ecological risk assessment for both Landfill 1 and the CAP.

6.1 SUMMARY OF RISKS AT LANDFILL 1

The Final RI conducted at Landfill 1 provided data that were used to support the Baseline Risk
Assessment. The Final RI focused on the source areas, although potentially affected media (groundwater,
surface water, and sediments) were also investigated and evaluated. (Groundwater and surface
water/sediments were the focus of RIs conducted for OU 4 and OU 13, respectively.) Investigations
revealed no distinct source within the contents of Landfill 1 that would indicate the presence of
hazardous substances in the investigated media. SVOCs present in surface soils at Landfill 1 may be
caused by asphalt found at or near the surface or by unburned fuels emitted by vehicles during site
activities. The relative lack of SVOCs in subsurface materials from Landfill 1 indicates that the
landfill contents are not a likely source. Pesticides were detected at very low concentrations in
groundwater, and were present at concentrations below background in soils and surface water, suggesting
that their presence at Landfill 1 is caused by the widespread use of pesticides at LAFB. Only arsenic,
cadmium, and lead were detected above published background values within and adjacent to the landfill,
but these detections may be a result of natural variations of background concentrations. Table 1
presents a summary of potential contaminants detected at Landfill 1.

In the human health risk evaluation, site-related contaminants in the soil at the landfill were not found
to pose an increased human carcinogenic risk in excess of the USEPA target risk range (1.0x10-4 to
1.0x10-6) to receptors participating in recreational activities in the vicinity of the landfill. The
risks were recalculated based on recent guidance on relative toxicity for carcinogenic PAHs and on dermal
absorption efficiencies (HAZWRAP, 1994), and are presented in Appendix P of the Final RI (ASI, 1994).
There was one analyte, arsenic, which is not considered site-related, which had carcinogenic risk above
the USEPA target risk range.

Table 2 presents human health risk assessment exposure parameters for Landfill 1. Table 3 presents the
total site risks under current land use.

Arsenic was the only analyte identified to present risks in exceedance of the USEPA target risk range.
These risks are based on an older child/teenager receptor inhaling dust during dirt biking activities.
However, arsenic was detected only once above background, at a concentration of 22.7 milligrams per
kilogram, which is less than 1.5 times the background concentration. Therefore, it is not considered to
be a site-related in the region.

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                     Table 1
SUMMARY OF POTENTIAL CONTAMINANTS OF  CONCERN
              SURFACE SOIL
    FROM 1990 TO 1994 RI SAMPLING DATA
             OU 2A LANDFILL 1
          LORING AIR FORCE BASE
       FREQUENCY
                          RANGE OF
                                                             MAXIMUMb
CONTAMINANT OF
METALS (jig/ kg) :
Aluminum
Arsenic
Barium
Beryllium
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Potassium
Selenium
Sodium
Vanadium
Zinc
SEMIVOLATILE ORGANICS (jig/kg) :
Acenaphtene*
Anthracene*
DETECTION DETECTION

10/10
10/10
10/10
8/10
2/10
10/10
10/10
10/10
10/10
10/10
10/10
10/10
10/10
1/10
10/10
10/10
2/10
6/10
10/10
10/10

1/11
1/11


12,500 - 17,700
5.1
33.4
0.43
1.
2,020
24.6
9.8
19.2
24,900
15.4
6,950
537
0
32.4
794
0.58
145
21.
55.



- 22.7
- 55.1
- 0.69
0-1.4
- 107,000
- 35.6
-15.0
- 27.5
- 33,700
- 123
- 9,730
- 755
.51
- 46.2
- 1,530
- 0.67
- 179
8 - 41.2
4 - 119

40
61
MEANa

14,460
8.33
43.84
0.50
0.66
24,682
28.79
11.53
21.87
27,965
33.59
8,244
660.95
0.104
38.55
1,048
0.38
123.3
27.2
66.73

179.32
181.23
BACKGROU:

25,400
16.2
93.3
1.8
0.21
69,700
56.9
18.5
65.6
47,100
22.6
12,700
1,400
0.17
73
2,900
0.71
110
40
83.9

c
c

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                                     Table 1
                   SUMMARY OF POTENTIAL CONTAMINANTS OF CONCERN
                                 SURFACE SOIL
                       FROM 1990 TO 1994 RI SAMPLING DATA

                                OU 2A LANDFILL 1
                             LORING AIR FORCE BASE

                            FREQUENCY         RANGE OF                      MAXIMUMb
     CONTAMINANT           OF DETECTION       DETECTION       MEANa       BACKGROUND
Benzo(a)anthracene*             6/11          41  -  280         165.41              c
Benzo(a)pyrene*                 3/11          68  -  220         185.59               c
Benzo(b)fluoranthene(1)*        6/11          71  -  710         337.45               c
Benzo(g,h,i)perylene*           3/11          49  -  220         183.82               c
bis (2-ethylhexyl)phthalate      9/11          42  -  170         115.05               c
Carbazole                        1/9             45            166.94               c
Chrysene*                       6/11          46  -  300         161.45               c
Dibenzo(a,h)anthracene*         1/11             54            180.59               c
Di-n-octylphthalate             3/11          73  -  220         177.77               c
Fluoranthene*                   7/11          58  -  670         228.27               c
Indeno(l,2,3-cd)pyrene*         3/11          44  -  200         183.59               c
Napthalene*                     1/11             69            181.05               c
Pentachlorophenol                2/8          40  -  180         506.56               c
Phenanthrene*                   3/11         120  -  360         201.59               c
Pyrene*                         7/11          65  -  460         192.18               c
PESTICIDES/PCBs (d)  (jig/kg) :
Aroclor-1260                    3/10          23  -  52           41.6               240
alpha-Chlordane                 5/10         0.39-3.3        10.73                c
gamma-Chlordane                 5/10         0.39-2.9        10.72                c
4,4'-DDD                        3/10         0.66 -  1.50        3.23                470
4,4'-DDE                        8/10         0.79 -  6.60        4.76                160
4,4'-DDT                        9/10         4.30 -  28.0       13.75                940
Endosulfan  II                  2/10         0.43-4.0         3.56                c

-------
                                       Table 1
                   SUMMARY OF POTENTIAL CONTAMINANTS OF CONCERN
                                 SURFACE  SOIL
                       FROM 1990 TO 1994  RI SAMPLING DATA

                                OU 2A LANDFILL 1
                             LORING AIR FORCE  BASE
     CONTAMINANT
Endrin Ketone
Heptachlor
Methoxychlor
MISCELLANEOUS  (mg/kg) :
Total Recoverable -
Petroleum Hydrocarbons
                   FREQUENCY
                     OF  DETECTION
                        2/10
                        1/10
                        1/10

                        6/6
RANGE OF
  DETECTION
 1.2 - 3.5
   0.17
    4.8

 51 - 2,800
MEANa
 3.61
 1.70
17.16

1,058.5
MAXIMUMb
BACKGROUND
  3
  0.2
  c
Notes:
a
c
d
(1)
The mean value represents the arithmetic average of all the samples; in the case of
non-detects, a value of one-half the SOL (or CRQLs if SOL cannot be obtained) is assigned
for each non-detected result.
Surface soil background concentrations data obtained form the Consensus Statement -
Background Concentrations for Soils, Surface Water, Sediments  (LAFB, 1994).
Background data are not available.
PCB/pesticides will not be removed from risk assessment data based on background
comparisons.

=     Includes benzo(k)fluoranthene
=     Polynuclear aromatic hydrocarbon

-------
                                       Table 2
                   HUMAN HEALTH RISK ASSESSMENT EXPOSURE PARAMETERS

                                OU 2A LANDFILL 1
                             LORING AIR FORCE  BASE

                                              OLDER  CHILD/
     PARAMETERS

Soil Ingestion Rate

Soil Adherence Factor


Surface Area Exposed


Fraction Ingested

Exposure Frequency

Exposure Duration

Body Weight

Averaging Time:

Cancer

Noncancer
(1-6 YES. )
Surface Soil -
200
1.0 - max .
0.6 - mean
2,295 - max.
1,983 - mean
100%
110
6
16
70
6
(7-16 YES. )
Ingestion and Dermal
100
1.0 - max
0.6 - mean
5, 400 - max.
4, 400 - mean
100%
110
11
40
70
11
(17-30 YES.)
Absorption
100
1.0 - max .
0.6 - mean
5,800 - max
5,000 - mean
100%
110
6
70
70
6
UNITS
Ug/kg
]lg/cm2
]lg/cm2
cm2

day/yr
yr
kg
yr
yr
SOURCE
EPA, 1991b
EPA, 1989a
EPA, 1989a
EPA, 1992
Assumption
Assumption
EPA, 1991b
EPA, 1991b
yr

-------
              Table 3
  TOTAL  SITE RISKS  UNDER CURRENT LAND USE

            OU 2A LANDFILL  1
         LORING AIR FORCE BASE
                             MEAN                      MAXIMUM
                            CONCENTRATIONS                CONCENTRATIONS
RECEPTOR EXPOSURE RATE
Child Soil Ingestion
Soil Dermal
Absorption
Total Soil
Older Child/Teenager Soil Ingestion
Soil Dermal
Absorption
Total Soil
Dust Inhalation
Adult Soil Ingestion
Soil Dermal
Absorption
TOTAL CANCER RISK
8.3x10-7
1.2x10-7
9.5x10-7
3.0x10-7
2.0x10-7
5.0x10-7
6.8x10-5
6.5x10-7
3.5x10-7
TOTAL CANCEI
l.lxlO-f
3.0x10-"
1.4x10-6
3.9x10-7
5.1x10-7
9.0x10-7
1.8x10-4
6.0x10-7
8.6x10-7
Total Soil                   1.0x10-6                     1.5x10-6

-------
                                         TABLE 4
            SUMMARY OF ECOLOGICAL RISK ASSESSMENT FOR TERRESTRIAL ORGANISMS

                                     OU 2A LANDFILL 1
                               LORING AIR FORCE  BASE

                              SUMMARY HAZARD  INDICES

     INDICATOR SPECIES          REASONABLE MAXIMUM            MOST PROBABLE          EXPECTED EFFECT

Short tailed Shrew                     1.4                           6.6               Effects  Possible

American Woodcock                       <1                          <1                Effects Unlikely

Garter Snake                            <1                          <1                Effects Unlikely

Fisher                                  <1                          <1                Effects Unlikely

Broad-winged Hawk                       <1                          <1                Effects Unlikely

-------
In the evaluation of risks to ecological receptors, lead is the only soil contaminant of concern (COG)
exceeding a hazard guotient of 1. Because average lead concentrations were only 1.5 times greater than
those of background lead concentrations, risks to terrestrial receptors from soil contamination at
Landfill 1 appear to be minimal. Short-tailed shrews ingesting soil or soil invertebrates from an area
with average soil concentrations may receive a daily dose of lead that exceeds a conservative
toxicological threshold be a factor of 4.8, but no other COCs exceeded levels of concern. Adverse
effects are unlikely (HI < 1) for the garter snake, American woodcock, fisher, and broad-winged hawk.
Although this evaluation identified Aroclor-1260, SVOCs and some inorganics as potential ecological risk
drivers in Green Pond sediment, the sources of these contaminants and their impact on ecological
receptors will be evaluated in depth in the investigation of OU 13, the surface water and sediment
operable unit. Table 4 presents a summary of ecological risk for terrestrial organisms.

Based on the evaluations, cadmium is not a risk to either human health or ecological receptors at the
reported concentrations within and adjacent to Landfill 1.

All media at Landfill 1 have been investigated to assess the nature and distribution of contamination and
to estimate risks to human and ecological receptors from landfill contents and affected media at the
landfill. The investigation indicates that detected SVOCs and inorganics are attributable to scattered
placement of construction debris, combined with transport of contaminants from other area or activities
not necessarily related to Landfill 1.

In summary, the human health and ecological risks associated with site-related contaminants in surface
soil and shallow subsurface soil at Landfill 1 and in the adjacent area do not exceed the USEPA target
risk range. The risks associated with surface water and sediments in Green Pond will be further
evaluated in the investigation of the surface water/sediment operable unit (OU 13). A removal action
has been completed for the CAP and the residual risks presented in the Removal Completion Report do not
exceed the USEPA target risk range.

6.2 SUMMARY OF RISKS AT THE CAP

The Final RI conducted at the CAP provided data that were used to support the baseline risk assessment.
The Final RI is focused on the source area, although potentially affected media (groundwater, surface
water, and sediments) were also investigated and evaluated to determine if any contamination has migrated
from the source area. OU 4 addresses groundwater associated with the landfills and Chapman Pit included
under OU 2 and OU 2A, while OU 13 addresses basewide surface water and sediments, including wetlands.
The potential source of contaminants at the CAP is the materials disposed there (coal ash, unburned coal,
and miscellaneous debris).

Several elevated detections of Aroclor-1260 in surface soils, subsurface soils, and sediments indicate
that PCB-containing wastes may have been disposed in the CAP. Pesticide detections in surface and
subsurface soils were at relatively low concentrations or were below background, which is consistent with
the widespread use of pesticides at LAFB.

Inorganics were found in excess of background in all media. In general, mean concentrations calculated
for each metal detected in surface and subsurface soils were below LAFB background values, indicating
detected concentrations can most likely be attributed to naturally-occurring concentrations in the
overburden material. Inorganic analysis of surface soil sample CSS-0008, a sample of the coal ash,
indicates that concentrations of metals detected in the coal ash are not significantly different from the
metal concentrations detected in the overburden material.

Table 5 presents the summary of potential contaminants in surface soil identified during the RI. Table 6
presents human health risk assessment exposure parameters for the CAP.

Contaminants from the soils/waster were found to pose potential human carcinogenic risks to receptors
participating in recreational activities in the vicinity of the CAP in excess of the MEDEP target risk
level (1x10-5) and the USEPA target risk range upper limit (1x10-4). Maximum carcinogenic risk to a
child from dermal contact with and incidental ingestion of soils/waste at the CAP was 2.4x10-3,
Carcinogenic risk to a teenager inhaling dust while dirt biking was 5.5x10-4. The greatest HI or
noncarcinogenic risk from dermal contact and incidental ingestion of soils/waste was 6.4, which exceeded
the USEPA HI target risk level of 1. Table 7 presents a summary of human health risk at the CAP.

-------
                                       TABIiE 5
                  SUMMARY OF POTENTIAL CONTAMINANTS IN SURFACE SOIL
                             1993 RI SAMPLING DATA

                                COAL ASH PILE
                            LORING AIR FORCE BASE
CONSTITUENTS
                      FREQUENCY OF
                     DETECTION
                  RANGE OF
                  DETECTION
                                       MEAN(a)
                                       MAXIMUM
                                      BACKGROUND(b)
METALS  (Ug/KG)

Aluminum
Arsenic
Barium
Beryllium
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Potassium
Selenium
Silver
Sodium
Vanadium
Zinc
12 of 12
12 of 12
12 of 12
 1 of 12
 5 of 12
12 of 12
12 of 12
12 of 12
12 of 12
12 of 12
12 of 12
12 of 12
12 of 12
 6 of 12
12 of 12
12 of 12
 1 of 12
12 of 12
 2 of 12
12 of 12
12 of 12
6950 - 16850
 49 - 15.1
 38 - 366
    3.4
 1.3 - 29.1
 2180 - 53700
 9.9 - 69.1
 6.4 - 28.9
 22.9 -  381
 5130 - 154000
 13.3 -  864
 674 - 8060
 63.5 -  1121
 0.15 -  1.6
 15.2 -  90.9
 806 - 1610
    4.0
  2.3 -2.5
 614 - 1230
  16.6 - 40
 38.4 -  5230
14083
8.38
95.63
0.85
3.59
16032
33.7
11.64
67.99
36523
153
6504
649
0.43
38.81
1269
0.86
1.14
245
27.69
631.7
25400
16.2
93.3
1.8
0.21
69700
56.9
18.9
65.6
47100
22.6
12700
1400
0.17
73
2900
<0.71
0.09
110
40.0
83.9
SEMIVOLATILE ORGANICS  (Ug/kg):
1,2, 4-Trichlorobenzne
Acenaphthene *
Anthracene*
Benzo(a)anthracene*
Benzo(a)pyrene*
Benzo(b)fluoranthene
Benzo(g,h,i)perylene*
1 of 12
2 of 12
3 of 12
8 of 12
5 of 12
8 of 12
2 of 12

78
57
47
130
65
320
200
- 210
- 580
- 7450
- 5200
- 13950
- 3900
322
315
330
908
695
1493
558
.5
.7
.6
.5

.75
.0
c
c
c
c
c
c
c

-------
                                   TABIiE 5
                 SUMMARY OF POTENTIAL CONTAMINANTS IN SURFACE SOIL
                             1993 RI SAMPLING DATA

                                     COAL ASH  PILE
                                LORING AIR FORCE BASE
CONSTITUENTS

Bis(2-ethylhexyl)phtl
Butylbenzlphthaiate
Carbazole
Chrysene*
Di-n-butylphthaiate
Dibenz(a,h)anthracen
Dibenzofuran
Fluoranthene*
Fluorene*
Indeno(1,2,3-c,d)pyn
N-Nitrosodiphenylan
Naphthalene *
Pentachlorophenol
Phenanthrene *
Pyrene*

PESTICIDES/PCBs(d)  (ug/kg):

4,4'-DDD
4,4' -DDE
4,4' -DDT
alpha-BHC
beta-BHC
delta-BHC
gamma-BHC  (Linda
Aldrin
alpha-Chlordane
gamma-Chlordane
Dieldrin
Endosulfan I
Endosulfan sulfate
Endrin
Endrin aldehyde
Endrin ketone
FREQUENCY OF
DETECTION
9 of 12
2 of 12
1 of 12
7 of 12
2 of 12
2 of 12
1 of 12
9 of 12
1 of 12
2 of 12
1 of 12
1 of 12
1 of 12
8 of 12
9 of 12
RANGE OF
DETECTION
46 - 2800
82 - 100
220
54 - 8450
73 - 980
100 - 1115
100
45 - 7450
240
400 - 4500
88
46
470
54 - 2200
53 - 10050

MEAN (a)
448.5
294.3
329.2
950.75
366.1
307.5
320.8
964.1
332.5
614.6
319.8
316.3
770
389.7
1179.2
MAXIMUM
BACKGROUND (b)
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
 8 of 12
10 of 12
 7 of 12
 2 of 12
 1 of 12
 2 of 12
 3 of 12
 2 of 12
 6 of 12
 9 of 12
 3 of 12
 2 of 12
 4 of 12
 2 of 12
 2 of 12
 1 of 12
0
0

0

0
0
0
0
0
0
0
0
0
1

.26 -
.68 -
1.5 -
.096 -
0.93
.21 -
.18 -
.17 -
.41 -
.68 -
.61 -
.59 -
.81 -
.87 -
.75 -
0.77
26
62.5
225
0.43

0.66
0.24
0.18
22
22
2.7
1.3
4.7
6.95
10

4.86
12.21
27.39
2.15
2.25
2.11
2.13
2.17
3.80
2.80
4.23
2.19
4.63
4.67
5.07
4.35
470
160
940
c
c
0.23
c
c
c
c
0.24
c
6.2
0.28
0.75
3

-------
                                   TABIiE 5
                  SUMMARY OF POTENTIAL CONTAMINANTS IN SURFACE SOIL
                                1993 RI SAMPLING DATA

                                COAL ASH PILE
                            LORING AIR FORCE BASE
CONSTITUENTS
                     FREQUENCY OF
                    DETECTION
Heptachlor            6 of 12
Heptachlor epoxide   6 of 12
Methoxychlor         7 of 12
Aroclor-1254         1 of 12
Aroclor-1260         5 of 12
RANGE OF
DETECTION

 0.12 - 2.3
 0.18 - 21
 1.04 - 89
    190
 60 - 43000
MEAN(a)

  1.97
   3.83
  25.57
    57.3
   3973
MAXIMUM
BACKGROUND(b)

0.2
0.11
 c
 c
240
NOTES:

(a)   The mean value represents the arithmetic average of all the  samples;  in  the  case  of
      non-detects, a value of one-half the SQL  (or CRQLs if  SQL cannot be  obtained)  is  assigned
      for each non-detected result.

(b)  Surface soil background concentration data was obtained from  the Consensus  Statement
     Background Concentrations for Soils, Surface Water, Sediment  (LAFB, 1994) .

(c)  Background data are either not available or are inappropriate if the  constituent is not
     naturally occurring.

(d)  Pesticides/PCBs will not be removed from risk assessment data based on background  comparisons.

(1)  Includes benzo(k)fluoranthene
* Polynuclear aromatic hydrocarbon

-------
                                                    TABIiE 6
                               HUMAN HEALTH RISK ASSESSMENT EXPOSURE PARAMETERS
                                                 COAL ASH PILE

                                                     OU  2A LANDFILL 1
                                                 LORING AIR  FORCE  BASE
     PARAMETERS



Soil Ingestion Rate

Soil Adherence Factc



Surface Area Exposec



Fraction Ingested

Exposure Frequency

Exposure Duration

Body Weight

Averaging Time:

Cancer

Noncancer
OLDER CHILD/
CHILD TEENAGER ADULT
(1-6 YES) (7-16 YES) (17-30 YES)
Surface Soil -
200
: 1.0- max .
0.6- mean
2,295 - max.
1, 983 - mean
100%
110
6
16
70
6
Ingestion and Dermal Absorption
100 100
1.0 - max . 1.0- max .
0.6 - mean 0.6 - mean
5,400 - max. 5,800 - max.
4,400 - mean 5,000 - mean
100% 100%
110 110
11 6
40 70
70 70
11 6
UNITS

mg/kg
mg/cm2
mg/cm2
cm2


day/yr
yr
kg
yr
yr
SOURCE

EPA, 1991b
EPA, 1989a
EPA, 1989a
EPA, 1992

Assumption
Assumption
EPA, 1991b
EPA, 1991b
yr

-------
                                                                     TABLE 7
                                                          SUMMARY OF HUMAN HEALTH  RISK
                                                               OU 2A COAL ASH  PILE
                                                              LORING AIR FORCE BASE
                          CHILD

SCENARIO             MAX        MEAN

RECREATIONAL  (current  and future)

Soil Ingestion       4.1E-1  7.9E-2

                       4.7E-2


TOTAL SOIL             4.6E-1

Dust Inhalation
                                           OLDER  CHILD
                                                     TEENAGER
       MEAN
1.3E-1

 6.4E+0
2.1E-2

1.7E+0
                                                    MEAN
                                                                5.4E-5
                                                                                                                                 CANCER RISK
                                                                             OLDER  CHILD
                                                                                    TEENAGER
                                                                              1.OE-4

                                                                              1.2E-3      4.9E-5
                                                                                                                          l.OE-4

-------
                                                  TABIiE 8
  INDICATOR SPECIES

Short-tailed Shrew

American Woodcock

Garter Snake

Fisher

Broad-winged Hawk
                      SUMMARY OF ECOLOGICAL RISK ASSESSMENT FOR TERRESTRIAL ORGANISMS
                                          COAL ASH PILE

                                         OU 2A LANDFILL 1
                                       LORING AIR FORCE BASE
              SUMMARY HAZARD INDICES

REASONABLE MAXIMUM            MOST PROBABLE

    28                             34

    3.2                             2.1

    3.4                            2.9

   <0.2                            <0.2

   <0.2                            <0.2
   EXPECTED EFFECT

Effects Probable

Effects Possible

Effects Possible

Effects Unlikely

Effects Unlikely

-------
Risk are most likely overestimated for PAHs and the dermal pathway because of the use of conservative
surrogates and absorption efficiencies. Benzo(a)pyrene, considered to be the most toxic of the PAHs, was
used as a surrogate for all carcinogenic PAHs lacking toxicity values. Dermal exposures to soils were
also calculated risk estimate most likely overestimates the risk to potential receptors. However, with
risk estimates on the order of 1.0x10-3 for soils, remedial action was warranted.

Calculated His indicate that adverse ecological effects to terrestrial wildlife exposed to contaminants
in soil and aguatic organisms exposed to contaminants in surface water or sediment are probable at the
CAP. Ecological risks as result of ingestion of soil, food, and water from the CAP were found to be
probable for the short-tailed shrew (His of 28 and 34 for maximum and average exposures, respectively)
and possible for the American woodcock (His of 3.2 and 2.1) and garter snake (His of 3.4 and 2.9). Risks
to the shrew are primarily associated with zinc, lead, cadmium, and selenium; risks to the woodcock and
snake are associated with zinc and lead, respectively. Adverse effects on the fisher and broad-winged
hawk were unlikely. Table 8 presents a summary of ecological risk for terrestrial organisms at the CAP.

Waster received at the CAP included coal ash, construction debris, and municipal wastes. Contaminants
produced by these wastes contributed to elevated levels of human and ecological risk that exceeded MEDEP
and/or USEPA target risk levels. Results from previous investigations indicated petroleum-contaminated
material and PCB-containing waste might have been disposed in the CAP.

Removal of materials from within the CAP has been conducted as part of a time-critical removal action in
accordance with 40 CFR 300.415. Approximately 140,000 cubic yards of material from the CADA has been
excavated and used as subgrade material for covers associated with Landfills 2 and 3 (AFCEE, 1995) .
Approximately 44,000 cubic yards of soil were removed from the DBA and PCDA in 1995 (AFCEE, 1996).
Removal of the CAP material is part of an on-going program to consolidate contaminated soils/materials
from various locations around LAFB for use as subgrade material under landfill covers associated with OU
2. A comparison of materials from the CAP to the Toxicity Characteristic Leaching Procedure Levels (55
Federal Register, March 19, 1980) has been performed. Results of this evaluation indicated that the CAP
material was below these levels; therefore, the material is suitable, without further treatment, for use
as subgrade material for the OU 2 landfill cover. Completion of the planned removal actions at the CAP
has mitigated additional risks associated with exposure to materials within the CAP. Because there are
no residual risks, no further action under CERCLA is necessary.

After removal actions at the CADA and DBA, confirmation sampling and analyses of soils at the bottom and
sides of the excavations detected some chemicals above PRGs. Residual risk assessments were performed
for both of these areas and the results are described in the following paragraphs.

At the CADA, silver was detected in concentrations up to 5 mg/kg, far below a human health PRG, but in
excess of a 2 mg/kg PRG based on a plant receptor. However, the plant toxicity benchmark for silver is
considered to be conservative and has a low level of confidence associated with it. In addition, soil
cover over the area will mitigate the remote potential for adverse effects due to exposure. Also at the
CADA, Aroclor-1260 was detected at concentrations which were below an ecological PRG but exceeded a human
health PRG by a small margin. The human health risk calculated for the Aroclor-1260 concentration is
within the USEPA target risk range. A Technical Memorandum containing additional details on the residual
risk assessment performed for the CADA is included as an attachment to Appendix B.

At the DDA, both benzo(a)pyrene and zinc were detected above PRGs in confirmation samples. For human
health, both compounds were within or below the USEPA target risk range. Benzo(a)pyrene concentrations
were well below an ecological PRG, but zinc contributes to a HQ above 1 for ecological receptors.
However, only one sample location had a concentration of zinc greater than two times the background
level, resulting in, at most, the potential for very localized effects to plants and invertebrates. Risk
for ecological receptors is further mitigated and minimized by covering the excavated area with at least
one foot of clean soil. A technical Memorandum containing additional details on the residual risk
assessment performed for the DDA is also included as an attachment to Appendix B.

7.0 DESCRIPTION OF THE NO ACTION ALTERNATIVE

Based on the results of the RI and Baseline Risk Assessment, no further remedial action under CERCLA in
necessary for OU 2A LAFB. No five-year site reviews will be conducted.

Although not reguired under CERCLA, it is recommended that Landfill 1 be classified as a construction
debris landfill. The remaining closure activities should be completed in accordance with the Maine Solid
Waste Regulations.

To close the landfill in accordance with the State of Maine Solid Waste Regulations, Chapter 401.6 and
404.5 (effective date May 24, 1989), a soil landfill cover system has been designed. Permits will not be

-------
required for cover construction. The proposed cover for Landfill 1 will consist of the following:

• 18 inches of well-graded soil with at least 35 percent fines;

• A final cover of 6 inches of soil suitable to support vegetative cover.

The primary objective of a construction debris landfill cover is to mitigate surface physical hazards. A
secondary objective is to reduce the impact on groundwater from infiltration through the landfill.
Additionally, the soil landfill cover system will mitigate any potential risk to ecological receptors
associated with surface soils at the site.

Post-closure activities would be performed at Landfill 1 for a minimum of ten years. O&M requirements are
minimal. Periodic site inspections and maintenance of the cover (e.g., mowing) are the primary
components of O&M for Landfill 1.

Contaminants identified to present or have the potential to present risk to human health and the
environment have been removed from the CAP under a time critical removal action. The rationale for this
removal action was described in the "Time Critical Removal Action Memorandum, Operable Unit 2A, Coal Ash
Pile Site," (AFCEE, 1994). Closure was documented in the "Remedial Action Report/Project Closeout
Report, OU 2, OU 2A, OU 6, OU 7, and Other Sites," (AFCEE, 1995), and in the "Removal Action
Report/Project Closeout Report for the PCDA and DBA", (AFCEE, 1996), satisfying the requirements under
Section 19.1 of the FFA.

Some chemicals detected in the soil after removal actions are above PRGs, but do not pose a risk to human
health. Zinc and silver exhibit localized ecological risk to plant receptors; however, this risk is
mitigated by covering the area with clean soil.

8.0 DOCUMENTATION OF NO SIGNIFICANT CHANGES

The Air Force prepared a Proposed Plan for OU 2A (ABB-ES, 1996) . The Proposed Plan described the Air
Force's decision to pursue no further action under CERCLA at OU 2A. There have been no significant
changes made to the No Action under CERCLA decision stated in the Proposed Plan.

9.0 STATE ROLE

MEDEP, on behalf of the State of Maine, reviewed the Final RI Report and Proposed Plan and indicated its
support for the selected remedy. MEDEP concurs with the selected remedy for OU 2A. A copy of the
declaration of concurrence is in Appendix C.

-------
                   GLOSSARY OF ACRONYMS AND ABBREVIATIONS
ABB-ES        ABB Environmental Services,  Inc.
AFCEE         Air Force Center for Environmental Excellence
CADA          Coal Ash Disposal Area
CAP           Coal Ash Pile
CERCLA        Comprehensive Environmental  Response,  Compensation,  and Liability Act
CPC           Contaminant of Potential Concern
CRP           Community Relations Plan
CRQL          Contract Required Quantitation Limits
CLP           Contract Laboratory Program
DBA           Drum Disposal Area
DOD           Department of Defense
FFA           Federal Facility Agreement
HI            Hazard Index
HQ            Hazard Quotient
IRP           Installation Restoration Program
LAFB          Loring Air Force Base
MEDEP         Maine Department of Environmental Protection
mg/kg         milligrams per kilogram
NCP           National Contingency Plan
NPL           National Priority List
O&M           Operation and Maintenance
OU            Operable Unit
PAHs          Polynuclear Aromatic Hydrocarbons
PCBs          polychlorinated biphenyls
PCDA          Paint Can Disposal Area
pRGs          Preliminary Remediation Goals
RAB           Restoration Advisory Board
RfD           reference dose
RI            Remedial Investigation
ROD           Record of Decision
SARA          Superfund Amendments and Reauthorization Act
SVOC          semivolatile organic compound
TAL           Target Analyte List
USAF          U.S. Air Force
USEPA         U.S. Environmental Protection Agency
jig/kg         micrograms per kilogram
VOC           volatile organic compound

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                              REFERENCES

ABB  Environmental Services, Inc.   (ABB-ES) , 1990.  "Remedial Investigation/Feasibility Study at Loring
     Air Force Base;  Status Report";  Installation Restoration Program; prepared for HAZWRAP; Portland,
     Maine; August 1990.

ABB  Environmental Services, Inc.   (ABB-ES), 1994.  "Base wide Surface Water/Sediment Operable Unit  (OU
     13) Interim Remedial Investigation Report"; Installation Restoration Program; prepared for HAZWRAP;
     June 1994.

ABB  Environmental Services, Inc.   (ABB-ES) 1995a.  "Preliminary Remediation Goals for Operable Unit 2A;
     Internal Technical Memorandum"; March 1995.

ABB  Environmental Services, Inc.   (ABB-ES), 1995b.  "Operable Unit  (OU 4) Remedial Investigation
     Report"; Final; Installation Restoration Program;  prepared for HAZWRAP; November 1995.

ABB  Environmental Services, Inc.   (ABB-ES), 1996.  "Operable Unit  (OU 2A) Proposed Plan"; Installation
     Restoration Program; prepared for HAZWRAP; January 1996.

Advanced Sciences, Inc.  (ASI), 1995 "Remedial Investigation Report for Operable Unit 2A  (OU 2A)"; Final;
     Installation Restoration Program; prepared for HAZWRAP; May 1995.

AFCEE, 1994.  "Time Critical Removal Action Memorandum"; Loring Air Force Base, Operable Unit 2A, Coal
     Ash Pile Site, December 1994.

AFCEE, 1995.  "Remedial Action Report/Project Closure Report, OU 2, OU 2A, OU 6, OU 7, and Other Sites";
     January 1995.

AFCEE, 1996.  "Removal Action Report/Project Closeout Report for the PCDA and DBA"; January 1996.

CH2M  Hill, 1984.  "IRP Records Search"; Loring Air Force Base; Limestone, Maine; January 1984.

E.C  Jordan Co.,  1989.  Remedial Investigation/Feasibility Study At Loring Air Force Base, Maine:
     Remedial Investigation Status Report"; Installation Restoration Program; prepared for HAZWRAP;
     Portland, Maine; May 1989.

HAZWRAP, 1994.  Loring Air Force Base Baseline Risk Assessment Methodology": Final; August 1994.

Maine Department of Environmental Protection (MEDEP), 1989.  "Solid Waste Management Regulations";
     Chapters 400-406, & 409; Bureau of Solid Waste Management; Augusta, Maine; May 23, 1989.

R.F. Weston, Inc.,  1988 "IRP Phase II Confirmation/Quantification"; Loring Air Force Base, Limestone,
     Maine; January 1988.

U.S. Environmental Protection Agency  (USEPA) , 1990a.  "National Oil and Hazardous Substances Pollution
     Contingency Plan  (National Contingency Plan)"; Code of Federal Regulations, Title 40, Part 300;
     Federal Register, Volume 55, Number 46, pp.  8666 et seg.;  March 8, 1990.

U.S. Environmental Protection Agency  (USEPA), 1990b.  "Toxicity Characteristics Leaching Procedures Final
     Rule"; Code of Federal Regulations; 55 FR page 11798, March 29, 1990.

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STATE OF MAINE

AROOSTOOK, ss.

              APPENDIX A

     TRANSCRIPT OF PUBLIC MEETING

                                CARIBOU, MAINE



        PUBLIC HEARING

    LORING AIR FORCE BASE
OPERABLE UNIT 2A PUBLIC HEARING
                         CARIBOU MUNICIPAL  BUILDING
                                 HIGH STREET
                               CARIBOU, MAINE
                              JANUARY 24, 1996
                                  7:15  P.M.
                            Pilip R. Bennett,  Jr.
                               Court Reporter
                              13 Vaughn  Street
                            Caribou, Maine  04736
                                207-498-2729

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          1
                                OPERABLE UNIT 2 A PUBLIC HEARING
          2

          3

          4                                 7:15 P.M.

          5

           6                                         MR.  FORBES:  Good evening

           7      and welcome to the public hearing to receive comments

           8      on the removal action at the Coal Ash Pile and the

           9      proposed plan for Operable Unit 2A at Loring Air

          10      Force Base.  Today's date is January 24th, 1996.  My

          11      name is Peter Forbes, the Remedial Project Manager

          12      for the Installation Restoration Program at Loring.

          13      Seated with me are Michael Nalipinski,  Remedial Project

          14      Manager at the US Environmental Protection Agency and

          15      Naji Akladiss, remedial Project Manager for the Maine

          16      Department of Environmental Protection.  They will be

          17      assisting me in receiving your comments.

          18          This hearing is being held in accordance with the

          19      provisions of the Comprehensive Environmental Response,

          20      Compensation, and Liability Act (CERCLA),  as amended in

          21      1986, also known as Superfund .  The act reguires federal

          22      facilities on the National Priorities List to present

          23      clean up proposals to the local community for comment

          24      and consideration before the final clean up decisions

          25      are made.  The purpose of this hearing is to receive

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     1                    OPERABLE UNIT 2 A PUBLIC HEARING





     2





     3     comments on the Proposed Plan for Operable Unit 2A,





     4     and the removal action at the Coal Ash Pile.





     5        Mr.   Philip Bennett from Aroostook Legal  Reporters





     6     will serve as the court reporter tonight,  preparing a





     7     verbatim record of the proceedings.   The verbatim





     8     record will become a part of the final clean up plan.





     9     The court reporter will be able to make a complete





    10     record only if he is able to hear and understand what





    11     you say.  With that in mind, please follow these ground





    12     rules.   Speak only after I recognize you and please





    13     address your remarks to me.  State your name and the





    14     organization you represent and present your statement.





    15     Please do not state your address or any other personal





    16     information which you do not wish to become a matter of





    17     public record.  Do not begin speaking until you have





    18     reached the microphone and speak slowly and clearly into





    19     the microphone.  If you have prepared your statement





    20     beforehand, you may read it aloud or you may paraphrase





    21     it and place it on this table.





    22          Are there any individuals wishing to make a comment





    23     or a statement at this time?





    24   Ladies and gentlemen,  it is 7:20 p.m.,  January 24,





    25     1996 and I declare the public hearing to receive

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           1                    OPERABLE UNIT 2 A PUBLIC HEARING





           2





           3     comments on the removal action at the Coal Ash Pile and





           4     the Proposed Plan for Operable Unit 2A at Loring Air





           5     Force Base closed.





           6





           7                        END OF HEARING
          9





         10





         11





         12





         13





         14





         15





         16





         17





         18





         19





         20





         21





         22





         23





         24





         25

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           1

           2

           3

           4

           5

           6

           7
            CERTIFICATION

I HEREBY CERTIFY THAT the foregoing is a true

and correct transcript of my stenographic notes

taken at the Operable Unit 2A Public Hearing on

the 24th day of January,  1996 at Caribou,  Maine.
           9

          10

          11

          12

          13

          14

          15

         16

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         25
             STATE OF MAINE

             AROOSTOOK,  ss.


                     
                                                         CARIBOU

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                                 APPENDIX B
                                    FINAL

                            Loring Air Force Base

                        OU 2A RESPONSIVENESS SUMMARY

                                 MARCH 1996

                                Prepared for:

                      Air Force Base Conversion Agency
                        Loring Air Force Base, Maine
                                (207) 328-7109

                                Prepared by:

          Service Center:  Hazardous Waste Remedial Actions Program
                            Oak Ridge, Tennessee

                Contractor:  ABB Environmental Services, Inc.
                               Portland, Maine

                            Project No.  9043-16

                              TABLE OF CONTENTS

Section                                  Title                        Page No.

PREFACE	 P-l

1. 0  OVERVIEW OF PREFERRED ALTERNATIVE	 1-1

2.0  BACKGROUND ON COMMUNITY INVOLVEMENT AND
     CONCERNS 	 2-1

3.0 SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC
     COMMENT PERIOD AND USAF RESPONSES 	 3-1

ATTACHMENT 1 -     TECHNICAL MEMORANDUM JUNE 8, 1995
ATTACHMENT 2 -     CORRESPONDENCE, JANUARY 4, 1996

The U.S.  Force (USAF) held a 30-day comment period from January 16 through February 14, 1996, to provide
an opportunity for the public to comment on the Proposed Plan and other documents developed for Operable
Unit No.  2A  (OU 2A) source control at Loring Air Force Base  (LAFB) , Maine.  The Proposed Plan is the
document that identities remedial action objective, evaluates remedial alternatives, and recommends the
alternatives that best meet the evaluation critical for OU 2A. The Air Force made preliminary
recommendations of its preferred alternative for remedial action at OU 2A in Section 6.0 of the Proposed
Plan, which was issued on January 12, 1996.  All documents on which the preferred alternative was based
are in the administrative record for review.  The administrative record is a collection of the documents
considered by the Air Force while choosing the remedial actions for the OU 2A source areas.  It is
available to the public at the following location:

       Air Force Base Conversion Agency Office
       5100 Texas Road
       Limestone, ME
       (207)  328-7109

The purpose of this Responsiveness Summary is to document Air Force responses to the guestions and
comments raised during the public comment period regarding the proposed OU 2A source controls.  The Air
Force considered all comments in this document before selecting a final remedial alternative to address
contamination from OU 2A.

A copy of this responsiveness summary will be included as Appendix B in the Record of Decision  (ROD) for
OU 2A.

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This Responsiveness Summary is organized into the following sections:

1.0    Overview of Preferred Alternative.  This section briefly outlines the preferred
       alternative presented in the Proposed Plan for OU 2A.

2.0    Background on Community Involvement and Concerns.  This section provides
       a brief history of community interest and concerns in OU 2A.

3.0    Summary of Comments Received During the Public Comment Period and
       USAF Responses.  This section summarizes and provides the USAF's
       responses to all written and oral comments received from the public during
       the public comment period.

                    1.0 OVERVIEW OF PREFERRED ALTERNATIVE

The following paragraphs outline the preferred final source control remedial alternative presented in the
Proposed Plan for OU 2A.  The Final Remedy for Ou 2A is set forth in the Record of Decision.

Based on the results of the Final Remedial Investigation  (RI), Draft Feasibility Study, Removal Action
Reports and Action Memorandum, and time-critical removal actions at the Coal Ash Pile  (CAP) site, no
remedial action under Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) is
considered necessary for OU 2A at LAFB.  Although the Draft Feasibility Study revealed a number of
alternatives the Air Force's preferred alternative is no action for the reasons set forth in the
transmittal memorandum  (January 5, 1996) for the "Removal Action Report/Project Closeout Report for the
Paint Can Disposal Area  (PCDA) and Drum Disposal Area  (DDA) "  (AFCEE, 1996) .

Although not reguired by CERCLA, a soil landfill cover system has been designed consistent with the State
of Maine Solid Waste Management Regulations, Chapter 401.6 and 404.5, effective date May 24, 1989.
Permits will not be reguired for cover construction.  The proposed cover for Landfill 1 will consist of
the following:

       •      18 inches of soil with at least 35 percent fines;  and

       •      a final cover of 6 inches of soil suitable to support vegetative cover.

The primary objective of a construction debris landfill cover is to mitigate surface physical hazards.  A
secondary objective is to reduce the impact on groundwater guality from infiltration through the
landfill.

No further action under CERCLA is recommended at the CAP site.  About 140,000 cubic yards of coal ash was
excavated from Coal Ash Disposal Area  (CADA) in 1994, and about 44,000 cubic yards of soil was excavated
from DDA and PCDA in 1995.  Residual risks at the site do not exceed the U.S. Environmental Protection
Agency  (USEPA) target risk range.  Removal of the contaminated CAP soil and incorporation of this soil
into the subgrade for capping Landfills 2 and 3 is consistent with removal action criteria described in
the NCP, which describes capping as an acceptable removal action for contaminated soil in order to reduce
migration of hazardous substances.

            2.0 BACKGROUND ON COMMUNITY INVOLVEMENT AND CONCERNS

Throughout LAFB's history, the community has been active and involved to a high level in base activities.
The Air Force, USEPA, and MEDEP have kept the community and other interested parties apprised of LAFB
activities through informational meeting, fact sheets, press releases, public meetings, site tours, and
open houses, and Restoration Advisory Board  (RAB) meeting.  Membership of the  RAB is composed of Air
Force, USEPA, MEDEP, and local officials, and community representatives.

The LAFB community relations plan  (CRP) was released in August 1991 and revised in May 1995.  The CRP
outlined a program to address community concerns and keep citizens informed and involved during remedial
activities.  The CRP can be found in the Administrative Record.

On June 24, 1992, the Air Force made the Administrative Record available for public review.  The
Administrative Record is currently available for public review at the office of the Air Force Base
Conversion Agency Office, 5100 Texas Road, Limestone, Maine.  The Air Force published a notice and brief
analysis of the Proposed Plan in the Bangor Daily News, the Aroostook Republican, the Fort Fair Field
Review and the Star Herald on January 10, 1996.

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From January 16 through February 14, 1996, the Air Force held a 30-day public comment period to accept
public input on the information presented in the RI/Baseline Risk Assessment and the Proposed Plan, and
on any other documents previously released to the public. On January 24, 1996, LAFB personnel and
regulatory representatives held a public meeting to discuss the Proposed Plan and to accept any oral
comments. A transcript of this meeting is included in Appendix A, and the comments received during the
comment period and the Air Force's response to these comments are included in the Responsiveness Summary
in Appendix B.

3.0 SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC
COMMENT PERIOD AND USAF RESPONSES

This Responsiveness Summary addresses comments received by the USAF and USEPA during the public comment
period from January 16 through February 14, 1996 relative to the Proposed Plan for OU 2A at LAFB.
Comments include those received from Caswell, Eichler & Hill dated January 24, 1996. No verbal comments
were received at the public hearing. The comments and corresponding responses are included herein.

Comment 1: Para. 4, p. 4-1; para. 4, p. 5-1. While the statements regarding risks at the CADA, DBA and
PCDA are not inconsistent with referenced residual risk analyses, the statement seem incomplete and may
be misleading. For instance, silver concentrations in soil remaining at the CADA exceeded Preliminary
Remediation Goals (PRGs) and general ecological exposure guidelines (i.e., hazard guotients exceeded 1).
The Air Force offered several points to consider when evaluation the silver exceedances. One suggested
that the exceedances did not warrant further consideration due to their magnitude. Others suggested that
the PRG was overly conservative due to the low confidence in the toxicological benchmark and naturally
high background concentrations of silver. And another suggested that removal action activities may have
partially mitigated the risks. We do believe that an estimate of residual risk from the silver at the
CADA is warranted at this time, the results of which should be referenced in the Proposed Plan. If the
PRG is overly conservative, as the Air Force contends, it should be corrected so that the calculated
risks can be used directly without a number of caveats. And, if removal action activities (i.e., the
placement of clean fill on the excavation site) have in some way affected the exposure scenario, this
should be factored into the risk calculation.

Further, zinc concentrations in soil remaining at the DDA exceeded PRGs and general ecological exposure
guidelines (i.e., hazard guotients exceeded 1). Again, the Air Force offered several points to consider
when evaluating the exceedances. One suggested that further consideration was not warranted due to the
magnitude and extent of the exceedances. One suggested that the toxicity benchmark was overly
conservative. And another suggested that removal action activities may have partially mitigated the
risks. We believe that the estimate of residual risk from the zinc at the DDA should be referenced in
the Proposed Plan. If the PRG is overly conservative, as the Air Force contends, it should be corrected
so that the calculated risks can be used directly without a number of caveats. If removal action
activities (i.e., the placement of clean fill on the excavation site) have in some way affected the
exposure scenario, this should be factored into the risk calculation. Additionally, if complete soil
removal has been affected to the bedrock (i.e., at sample location DD004, reference Table 3-2 of the
Removal Action Report for the DDA and PCDA) , it may be appropriate to eliminate these areas from further
consideration. Finally, we are inclined to agree with the Air Force's recommendation that further soil
removal or sampling is not warranted at the DDA but, would like to reserve our final comment until we
receive responses to the issues contained in this paragraph from the Air Force.

USAF Response: The Air Force will add to Section 6 of the OU2A ROD an explanation that some chemicals
exceeding PRGs remained in the soil at the CADA and the DDA. The following paragraphs explain the
strategy for addressing residual concentrations after performing a removal or remedial action.

Preliminary remediation goals (PRGs) are developed prior to any removal action. Risk based PRGs are
developed using approved methods and benchmark values presented in the Loring Air Force Base Risk
Assessment Methodology (HAZWRAP 1994). In general, the approach at Loring AFB has been one grounded in
conservatism, so that decisions can be made definitively if concentrations are near the PRGs. After the
removal action, confirmatory sampling is done to ascertain if PRGs2 have been met. Any compound that
exceeds the PRG is carried into the residual risk assessment screening.

For human health, the maximum detected concentration from the confirmatory sampling is put into the most
conservation exposure scenario that would be expected at the site. If risk is within or below the U.S.
Environmental Protection Agency (EPA) target risk range and below the Maine Department of Environmental
Protection (MEDEP) target risk level, then the removal action is determined to be successful.

For ecological risk assessment, residual risk calculations simply consist of comparing the maximum
detected concentration to the PRG or appropriate toxicological benchmark to obtain a hazard guotient for
the compound. Ecological risk assessment is inherently a more gualitative process when interpretation is

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done. There is no standard data base for toxicity values as there is for human health; therefore,
benchmarks are chosen based on literature searches. The benchmarks selected for Loring AFB have
purposefully been chosen to be conservative so that risk is more likely to be overestimated than
underestimated. In addition, because most studies are done in laboratory conditions, the natural or
background conditions of an area may also be taken into account when interpreting risk to ecological
receptors. It is unlikely that a background concentration of an inorganic would cause adverse effects to
a native ecological population.

The maximum detected concentration is used as a conservative residual risk screen as well. If risks are
significantly above the target risk level, other factors are considered in order to determine if further
removal actions are reguired. These factors included the distribution of detections, the freguency of
detection, and the number of compounds detected above the PRG.

In response to the comment that "If the PRG is overly conservative...it should be corrected...",
literature searches were performed and benchmark values selected in accordance with the agreed upon
approach to use conservative toxicity values in order to make decisions definitively. In the case of the
CADA, the compound under consideration is silver. Information on the toxicity of silver to ecological
receptor is sparse. The benchmark that was used was found in Will and Suter (1994), which stated, "There
were no primary reference data showing toxicity of silver to plants grown in soil." The benchmark is a
secondary reference, with no primary reference given, and is based on general adverse effects.
Therefore, the benchmark cannot be revised. It is standard and necessary practice in ecological risk
assessment to consider factors such as the certainty of the toxicity value, the concentration relative to
background, and the localization of the detections when interpreting ecological risk assessments.

At the CADA, silver and Aroclor-1260 exceeded PRGs and are discussed in the Technical Memorandum
(Attachment 1) entitled "Residual Risk Screening for the Coal Ash Pile Disposal Area Removal at Loring
Air Force Base" June 8, 1995. A residual risk assessment was performed, but an estimate of the human
health risk from silver was not provided because the human health PRG calculated (1327.27 mg/kg) for
comparison purposes was far above concentrations detected in confirmation sampling. The conclusion of
the Technical Memorandum is that silver and Aroclor-1260 do not present a risk to human health or the
environment at the CADA.

At the DDA the chemicals benzo(a)pyrene and zinc exceeded PRGs and are discussed in correspondence
(Attachment 2) from HAZWRAP to the Air Force dated January 4, 1996. The letter reports on a residual
risk analyses with a finding that neither chemical contributes to a human health risk above regulatory
guidelines. Only zinc contributed to a HQ above 1 for ecological receptors. The letter concludes further
soil removal is not warranted at the DDA.

The following paragraphs will be added to Section 6.2 of the ROD.

"After removal actions at the CADA and DDA, confirmation sampling and analyses of soils at the bottom and
sides of the excavations detected some chemicals above PRGs. Residual risk assessments were performed
for both of these areas and the results are described in the following paragraphs.

At the CADA, silver was detected in concentrations up to 5 mg/kg, far below a human health PRG, but in
excess of a 2 mg/kg PRG based on a plant receptor. However, the plant toxicity benchmark for silver is
considered to be conservative and has a low level of confidence associated with it. In addition, soil
cover over the area will mitigate the remote potential for diverse effects due to exposure. Also at the
CADA, Aroclor-1260 was detected at concentrations which were below an ecological PRG but exceeded a human
health PRG by a small margin. The human health risk calculated for the Aroclor-1260 concentration is
within the USEPA target risk range. A Technical Memorandum containing additional details on the residual
risk assessment performed for the CADA is included as an attachment to Appendix B of the ROD.

At the DDA, both benzo(a)pyrene and zinc were detected above PRGs in confirmation samples. For human
health, both compounds were within or below the USEPA target risk range. Benzo(a)pyrene concentrations
were well below an ecological PRG, but zinc contributes to a HQ above 1 for ecological receptors.
However, only one sample location had a concentration of zinc greater than 2 times the background level,
resulting in, at most, the potential for very localized effects to plants and invertebrates. Risk for
ecological receptors if further mitigated and minimized by covering the excavated area with at least one
foot of clean soil. A Technical Memorandum containing additional details on the residual risk assessment
performed for the DDA is also included as an attachment to Appendix B of the ROD."

Comment 2: Para. 2, p. 6-2. There is no mention of the residual risks at the CADA and the DDA. For
completeness, a reference should be made to paragraphs listed in Comment 1 above.

USAF Response: The following sentence will be added to Section 7.0 of the ROD. The proposed plan will
not be revised.

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"Some chemicals detected in the soil after removal actions are above PRGs, but do not pose a risk to
human health.  Zinc and silver exhibit localized ecological risk to plant receptor; however, this risk is
mitigated by covering the area with clean soil."

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                                      ATTACHMENT 1
                           TECHNICAL MEMORANDUM JUNE 8, 1995

MEMORANDUM FOR
Michael Nalipinski
US Environmental Protection
Agency
JFK Federal Building
Mail Code HAN CAN-2
Boston MA  02203-2211
        Naji Akladiss
       Maine Department of
Environmental Protection
       State House Station 17
       Augusta ME  04333-0017

           
FROM:   AFBCA/OL-M
       RR 1, Box 1719
        Limestone ME  04750-9743

SUBJECT:  Residual Risk Screening for the Coal Ash Disposal Area  (CADA) within Operable Unit  (OU) 2A

1.  A Technical Memorandum entitled Residual Risk Screening for the Coal Ash Pile Disposal Area  at Loring
Air Force Base has been prepared to evaluate the confirmation sampling data collected during  the removal
action at the Coal Ash Pile site.  The Technical Memorandum has been attached for your review.   Based on
our analysis, the current concentrations that exist at the CADA do not present a risk to human health or
the environment.  A similar evaluation will be performed on the confirmation sampling data collected from
the Drum Disposal Area (DDA) and the Paint Can Disposal Area  (PCDA) once these areas have been excavated
and disposed of at Landfill 3.
2.  Distribution of the subject document is as follows:
        a. U.S. Environmental Protection Agency  (USEPA), three
           Hailliburton-NUS;
        b. Maine Department of Environmental Protection  (MDEP), four
        c. AFBCA/NE, one  (1) copy;
        d. U.S. Fish and Wildlife Service, one  (1) copy;
        e. Air Force Center for Environmental Excellence  (AFCEE), for  (4) copies;
        f. Loring Development Authority  of Maine, one  (1)  copy to Limestone,  one
           Technical Advisor.
                                              (3) copies to Region I. five copies  (5) to

                                                    (4) copies to Augusta;



                                                                 (1) copy to  the
3.  If you have any questions, please call me or Denis St. Peters at  (207) 328-7109.

                                                       

Attachment:
Technical Memorandum

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TECHNICAL MEMORANDUM

Residual Risk Screening for the Coal Ash Pile Disposal Area Removal
at Loring Air Force Base
June 8, 1995

The analytical results from the Coal Ash Disposal Area (CADA) removal confirmation sampling were compared
with the preliminary remediation goals (PRGs) developed for the Coal Ash Pile site. The analytical
results were taken from the Remedial Action Report Report/Project Closeout Report, OU2, OU 2A, OU 6, OU7,
and Other Sites (AFCEE, January 1995) and the PRGs were taken from the PRGs for the Coal Ash Pile Site
Operable Unit (OU 2A) Technical Memorandum Report (ABB-ES, April 1995). The results of this comparison
are summarized in Table 1 (attached).

Only two chemicals of concern, silver and Aroclor-1260, exceeded the PRGs in the confirmation samples.
Although the PRGs of 2 for these compounds were slightly exceeded, the following points should be
considered:
Silver
• Silver exceeded the PRG of 2 mg/kg in 13 samples, but the highest detection was only 5 mg/kg. the
hazard guotient for silver at the maximum concentration detected is 2.5, indicating adverse
affects are unlikely.
• The PRG for silver is based on a plant receptor. According to the Toxicological Benchmarks for
Screening Potential Contaminants of Concern for Effects on Terrestrial Plants (Will and Suter,
September 1994), there is a low confidence in the benchmark for silver. This results in an overly
conservative estimate of risk. A portion of this document is attached for your reference.
• Ecological exposures, which are assumed to occur within the top 2 ft below ground surface, are
further mitigated by the addition of up to 1 ft of clean fill to the excavation site.
• A human health PRG for silver of 1327.27 mg/kg was calculated for comparison purposes (Attachment
2). This number is significantly higher than the concentrations of silver detected in the
confirmatory sampling.
• Silver was not detected in the groundwater, surface water, or sediment samples during the OU 2A
Remedial Investigation (RI). Therefore, it does not appear to be migrating.
• The uniform distribution of silver in the confirmation samples and the absence of silver in the
subsurface soil samples from the CADA (the two detections in the RI sampling were from the Drum
Disposal Area and the Paint Can Disposal Area) indicate naturally high background rather than
contamination.

Aroclor-1260

• Aroclor-1260 exceeded the PRG of 0.12 mg/kg in two samples by a small margin. The PRG for
Aroclor-1260 is based on an older child trespasser scenario. The risk from Aroclor-1260 at the
maximum concentration detected is 2.73 x 10-6, which is below the Maine Department of
Environmental Protection target risk range of 1 x 10-5 and within the U.S. Environmental
Protection Agency target risk range of 1 x 10-4 to 1 x 10-6.
• The concentrations of Aroclor-1260 detected in the confirmation samples were both below the
ecological PRG of 1.8 mg/kg.
• Risk would be further mitigated by the addition of clean fill to the excavation site.

The analysis indicates that the presence of silver and Aroclor-1260 does not present a risk to human
health or the environment at the CADA. Therefore, it is not necessary to perform an estimate of residual
risk at this site.

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                                                     TABIiE  1
           Screening of Proposed PRG' s with Analytical Results  for the Coal Ash Pile Removal Action
                                             OU-2A:   Coal  Ash Pile
                                               Loring Air Force  Base
Chemical of Concern
(mg/kg)
Silver
Silver
Aroclor-1260
Aroclor-1260
Proposed PRG (mg/kg)

         2
         2
         2
         2
         2
         2
         2
         2
         2
         2
         2
         2
         2
         0.12
         0.12
Environmental Sample
                 Analytical  Results
     CAP01CFD-
     CAP01CSA-
     CAP03CSA-
     CAP04CSA-
     CAP05CSA-
     CAP06CSA-
     CAP07CSA-
     CAP08CSA-
     CAP09CSA-
     CAP10CSA-
     CAP11CSA-
     CAP12CSA-
     CAP13CSA-
     CAP06CSA-
     CAP07CSA-
41000652-
41000651-
41000635-
41000636-
41000637-
41000638-
41000640-
41000641-
41000643-
41000642-
41000644-
41000646-
41000657-
41000638-
41000640-
•WC-2006
•WC-2005
•WC-2012
•WC-2013
•WC-2014
•WC-2015
•WC2017
•WC-2018
•WC-2020
•WC-2019
•WC-2021
•WC-2023
•WC-2024
•WC-2015
-WC-2017
 4
 4
 5
 5
 4
 5
 4
 4
 4
 4
 4
 5
 4
.230P
.300P
notes
J = Concentrations estimated; reported below  the  sample  guantitation limit
P = Pesticides/PCBs only:  Quantitation  is  estimated  since  percent  difference between the
    primary guantitation column and  secondary confirmation  column is greater than 25%

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                                       M. E. Will
                                     G. W. Suter II

                                  Date  Issued-September  1994

                                       Prepared by
                              Environmental Sciences Division
                              Oak Ridge National Laboratory
                                  under direction from the
                        Environmental Restoration Risk Assessment  Council

                                      Prepared for
                                  U.S. Department of Energy
                     Office of Environmental Restoration and  Waste Management
                            under budget  and reporting  code  EW  20

                               OAK RIDGE  NATIONAL LABORATORY
                              Oak Ridge,  Tennessee  37831-6285
                                        managed by
                               MARTIN  MARIETTA ENERGY  SYSTEMS,  INC.
                                          for the
                                  U.S. DEPARTMENT OF ENERGY
                               under contract DE-AC05-840R21400

-------
                                            Attachment 2

             Calculation of a Human Health Preliminary Remediation Goal for Silver
                for the Coal Ash Pile, Operable Unit 2A, Loring Air Force Base

Silver was selected as an ecological contaminant of concern  (COG) in the Operable Unit  (OU) 2A Remedial
Investigation  (RI) Report.  Silver was not selected as a COG for the human health risk assessment,
because it was screened out during the concentration/toxicity screening procedure used in the selection
of COCs.

For comparison purposes, a human health Preliminary Remediation Goal (PRG) was calculated based on the
ingestion of silver and noncarcinogenic effects.  Toxicity values are not available for carcinogenic
effects or for noncarcinogenic effects due to inhalation.  The dermal pathway is essentially
insignificant.

The parameters used in the equation were taken from the OU 2A RI Report recreational child receptor
scenario.

Oral RfD  (RfD) = 5.0e-03
Ingestion Rate of Soil  (IR) = 200 mg/day
Conversion Factor (CF) = 10-6 kg/mg
Exposure Frequency (EF) = 110 days/yrs
Exposure Duration (ED) = 6 years
Body Weight  (BW)  = 16 kg
Averaging Time (AT)  = 6 years
Concentration in Soil  (CS) = PRG

Equation:        CS = BW x AT x 365 days/yr x RfD
                   IR X CF X EF X ED

The resultant PRG is 1327.27 mg/kg for silver in soils.  The concentration of silver in soil detected in
the confirmatory sampling at the Coal Ash Pile is significantly lower than this value.  This value is
based on site specific exposures and should not be applied to other sites at Loring Air Force Base.

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CORRESPONDENCE, JANUARY 4, 1996

Dear Mr. St. Peter:

Drum Disposal Area Residual Risk Assessment

Per your request, the Hazardous Waste Remedial Actions Program has calculated residual risk based on the
results of confirmation sampling at the Drum Disposal Area (DDA) in Operable Unit 2A. Because of further
removals at sampling location DD008, sampling results from this location were excluded from residual risk
calculations. Sampling location DD102 was also not included in the residual risk calculations because
the sample was taken in an area where pieces of asphalt pavement are located, and the sample is not
indicative of the level of contamination at the site.

Only benzo(a)pyrene and zinc were detected above their respective Preliminary Remediation Goals (PRGs).
The maximum detected concentration was used in the residual risk calculations. Table 1 shows the
calculations risk levels associated with these compounds through the ingestion and dermal contact
exposure routes for the most conservation receptor, the child trespasser. Neither inhalation toxicity
values nor dermal absorption efficiencies are available for benzo(a)pyrene or zinc.

Benzo(a)pyrene contributes a carcinogenic risk of 1.7 x 10-6. This risk level is within the U.S.
Environmental Protection Agency (EPA) target risk range and below the Maine Department of Environmental
Protection (MEDEP) target risk level. Zinc contributes a noncarcinogenic HQ of 0.0046, which is below
the EPA and MEDEP target Hazard Index of 1.

In considering ecological receptors, the maximum concentration of benzo(a)pyrene detected of 0.73 mg/kg
is well below the PRG Of 34. Zinc was detected at a maximum concentration of 366 mg/kg. This value
exceeds the PRG of 93.9 based on background, resulting in a hazard quotient (HQ) of 18.3. The toxicity
benchmark for plant exposure is 20 mg/kg, indicating that the literature toxicity value for zinc is
overly conservative because plants are not likely to be adversely affected below the background level.
The detection would also exceed a PRG based on invertebrate exposure to zinc (130 mg/kg,) resulting in a
HQ of 2.8.

In summary, neither benzo(a)pyrene nor zinc contributed to a human health residual risk above regulatory
guidelines. Only zinc contributed to a HQ above 1 for ecological receptors. Location DD004 is the only
location where zinc exceeds the background concentration by more than a factor of 2. It is possible that
this location could present a localized risk of adverse effects to plants. However, all other detections
of zinc are less than two times the background concentration and are unlikely to cause adverse effects.
Risk at the DDA is further mitigated by the placement of at least 1 ft of clean fill across the site.
Therefore, further soil removal or sampling is not warranted at the DDA.

Please call me at 423-435-3291 if you have any questions or if you require additional information.

Sincerely,

BTS:

Attachment

c/attn.: S. H. Stines
File-RC-0770

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translocated to all parts of the plant, including the seed, in low molecular weight compounds (Broyer et
al. , 19972). Toxicity symptoms include chlorosis, stunting, and yellowing of the leaves. The mechanism
of toxicity is thought to be indiscriminate replacement of S by Se in proteins and nucleic acids with
disruptions in metabolism (Trelease et al. 1960)

3.1.23 Sliver

Experiments Conducted in Soil

There were no primary reference data showing toxicity of Ag to plants grown in soil. We have low
confidence in the benchmark because it is based on a report of unspecified toxic effects on plants grown
in a surface soil with the addition of 2 ppm Ag (Kabata-Pendias and Pendias, 1984) .

Experiments Conducted in Solution

Wallace (1979) examined the effect of Ag from AgNO, on shoot weight of bush bean seedlings grown in
nutrient solution (pH 5) for 13 days. Silver at 0.16 ppm reduced shoot weight 58% while 0.016 ppm had no
effort.

Confidence in the 0.1 ppm benchmark for toxicity to plants growing in solution is low due to lack of
data.

Mechanism of Phytotoxicity

Silver taken up by plants remains in the root system precipitated with phosphate or chloride (Ward et
al. , 1979) . The toxicity of Ag is related to the binding potential Ag ions to enzymes and other active
molecules at cell surfaces (Cooper and Jolly. 1970).

3.1.24 Technetium

Experiments Conducted in Soil

Wildung et al. (1977) investigated the affect of Tc on wheat and soybean grown in a silt loam soil (pH
6.8, % organic matter 1.4 ) from seed for 30 days. Addition of 1 ppm Te as TcOA reduced shoot weight of
wheat 100% and soybeans 99%, while 0.1 ppm had no effect.

Confidence in the benchmark of 0.2 ppm Te is low because it is based on this study alone. The authors'
chose to divide the LOEC by 5 because although it was not expressed as such in the study, the severity of
the effects seemed to border on mortality of the plants.

Experiments Conducted in Solution

Berlyn et al. (1980) conducted several experiments to examine the effect of Te on fresh weight of soybean
seedlings. When seedlings were germinated and allowed to grow for 20 days in nutrient solution
containing 0.2 ppm Te(TcO) plant weight was reduced 31% Technetium at

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Jenne,  E.A., and S.N. Luoma.  1977.  "Forms of trace elements in soils.  sediments, and
     associated waters:  An overview of their determination and biological activity.  InH.

Drucker  and R.E Wildung (eds)  Biological Implications of Metals in the Environment.
     CONF-750929. Tech. Info. Ctr., ERDA.  Washington pp. 110-143

John, M.K.  1973.  "Cadmium uptake by eight food crops as influenced by various soil levels of
     cadmium." Environ. Pollut. 47-15.

John, M.K. and C. Van Laerhoven.  1972. "Lead uptake by lettuce and oats as affected by lime,
     nitrogen, and sources of lead." J. Environ. Quai. 1(2):169-171.

John, M.K., H.H,. Chuah, and C.  Van Laerhoven.  1972a.  "Cadmium contamination of soil and
       its uptake by oats." J.  Environ. Qual.  6(6):555-557.

John, M.K., C. Van Laerhoven. and H.H.  Chuah.   1972b.  "Factors affecting plant uptake and
       phytotoxicity of cadmium added to soils.  "Environ. Sci.  Technical.   6(12):1005-1009

John, M. K., H.H. Chuah, and C.J. Van Laerhoven.  1977.  "Boron response and toxicity as
       affected by soil properties and rates of boron."  Soil Sci.  124:34-39

Johnson, C.M.  1966. "Molybdenum".  In Diagnostic Criteria for Plants and Soils.  Chapman,
       H.D. (ed.).   Univ.  of California,  Div Agric.  Sci., Riverside.

Kabata-Pendias, A., and H.  Pendias.  1984.  Trace Elements in Soils and Plants.  CRC Press, Inc.
       Boca Raton,  Flordia.

Kaplan, D.I., B.C.  Adriano.  C.L. Carlson.  and K.S. Sajwan.   1990.  "Vanadium:  Toxicity and
       accumulation by beans."   Water,  Air and Soil  Pollut.  49:81-91.

Keltjens,  W. G.  1990.  "Effects of aluminum on growth and nutrient status of Douglas-fir
       seedlings grown in culture solution."  Tree Physiol 6:165-75

Khalid, B.Y. and J. Tinsley.  1980 Some effects of nickel toxicity on rye grass."  Plant Soil 55/139-44.

Khan, D. H. and B.  Frankland.  1983.  "Effects of cadmium and lead on radish plants with
       particular reference to  movement of metals through soil profile and plant."   Plant Soil.
70:335-345.

Khan,  D.  H. and B. Frankland.   1984.  "Cellulolytic activity and root biomass production in
      some metal-contaminated soils."  Environ. Pollute.  33:63-74.

Koeppe, D.E.  1981.  "Lead:  Understanding the minimal toxicity of lead in plants."  In:  N.W.
         Metal Pollution on Plants.  Vol 1.  Effects  of Trace  metals on Plant

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TABIiE 1. REASONABLE MAXIMUM RISK CALCULATIONS FOR INGESTION AND DERMAL ABSORPTION OF
          SOIL BY A TRESPASSING/EXPLORING CHILD AT OU-2A - drum disposal area.
EXPOSURE PARAMETERS
                                                                       EQUATIONS
PARAMETER
                            SYMBOL
                                                VALUE
                                                              UNITS
                                                                                   SOURCE
Concentration in soil
Ingestion Rate
Fraction Ingestion
Soil Adherence Factor
Surface Area Exposed
Dermal Absorption Ellicie
Conversion Factor
Body Weight
Exposure Frequency
Exposure Duration
Averaging Time
                  Cancer
              Non cancer
   Permeability Constant
               Ingestion
                  Dermal
CS
IR
FI
SAF
SA
AE
CF
BW
EF
ED
AT
AT
PC
Comp.
Comp.
Max.
200
100%
1.00
2,295
0.06
0.000001
16.00
110.000000
6
70
6

Specific
Specific
mg/kg
mg/day

mg/cm3
cm3/day
unitless
kg/mg
kg
days/year
years
years
years



CANCER RIS1
EPA, 1991b
Assumption
EPA, 1989a
EPA, 1992
EPA, 1992
INTAKE = (:
EPA, 1991b
Assumption
Assumption
EPA, 1989a
Assumption

EPA, 1989b
EPA, 1989b
 INTAKE (mg/kg-day)x CSF  (mg/kg-day)-1
 HAZARD QUOTIENT = INTAKE (mg/kg-day)  / RID (mg/kg day)




AKE-INGESTION) +  (INTAKE-DERMAL)

 INTAKE- INGESTION = CS X IR X FI X CF X FF X ED
                    BW  x  ATx365  days/yr
 INTAKE-DERMAL
                = CS X SA X SAF X CF X FFx ED
                   BW x AT  x  365  days/yr
References:
EPA, 1989a.  Risk Assessment Guidance for Superfund
EPA, 1989b.  Supplemental Risk Assessment Guidance
EPA, 1991.  Standard Default Exposure Factors
EPA, 1992.  Dermal Exposure Assessment:  Principles and Applications
                                                                                          Note:
 CSF - Cancer Slope Factor
 RID - Reference Dose
 HO - Hazard Quotient
 COG - Constituent of Concern
                                          05 Jan 96

-------
CARCNOGENIC EFFECTS
  INTAKE
 INGESTION
(mg/kg-day)
                                                          DERMAL
                                                            AE
INTAKE
    DERMAL
  (mg/kg-day)
                                       CANCER
                                        RISK
                                  INGESTION
                                                                                                                                                             CANCER
                                                                                                                                                              RISK
                                                                                                                                                       DERMAL
 TOTAL
CANCER
 RISK
                                    2.4E-07
                                    1.2E-04
                                          NA
                                          NA
NONCARINOGENIC  EFFECTS
                                                          DERMAL
                                                            AE
    INTAKE
    DERMAL
  (mg/kg-day;
 INGESTION         DERMAL
    RID             RID
(mg/kg-day)  1  (mg/kgday)  1
                                                                      SUMMARY HAZARD INDEX
NA = No value  available
- No calculation  because invalid exposure pathway or no toxicity value available
                                                                                                                                                                             4.6E-03
                                                                                                                                                                             4.6E.03

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APPENDIX C
IiETTERS OF CONCURRENCE

February 5. 1996

Mr. Peter Forbes
Air Force Base Conversion Agency

Operation Location "M"
RR #1, Box 1719
Limestone, Maine 04750

Re: Loring Air Force Base Superfund Site, Maine

Dear Mr. Forbes:

The Maine Department of Environmental Protection (MEDEP) has reviewed the January, 1996 Draft Final
Record of Decision (ROD) regarding Operable Unit 2A (OU 2A) for the Loring Air Force Base Superfund Site
located in Limestone, Maine

Based on the Draft Final ROD, the MEDEP concurs with the Air Force's determination that no action under
CERCLA is necessary to address the contamination at OU2A. The MEDEP also concurs with the following
recommendations:

1. The Air Force and USEPA have determined that no further CERCLA action is reguired at OU2A.
Remaining closure activities for Landfill 1 will be completed in accordance with Maine Solid Waste
Management Regulations.

2. The time critical removal action performed at the Coal Ash Pile (CAP), as described in the "Time
Critical Removal Action Memorandum, Operable Unit 2A, coal Ash Pile Site". (AFCEE, 1994) provides
closure at the CAP.

3. USEPA in consultation with the state has the authority to revisit the No-Action under CERCLA
decision even if Loring is removed from the NPL. This could occur if future conditions indicate
that an unacceptable risk to human health or the environment would result from exposure to
contaminants at Landfill 1 or from the CAP.

Clean Up Levels:

The remedial alternative selected for the site must achieve goals for reducing contamination at OU2A.
Clean-up goals for OU2A have been set for contaminated soil and sediment, based either on background
concentrations, analytical detection limits, or on risk calculations.

Tables 1 through 8 list the compounds and elements for which a remedial goals have been set, as well as
the summary of risk associated with the sites included in this OU.

Description of No Action Alternative

The following describes the no action remedial alternative developed for Operable Unit 2A at Loring:

Based on the result of the remedial investigation (RI) and Baseline Risk Assessment, no further remedial
action under CERCLA is considered necessary for OU 2A at LAFB.

The DEP accepts the Air Force's recommendation that Landfill 1 be classified as a construction debris
landfill with no CERCLA reguirement for action. As such, the remaining closure activities should be
completed in accordance with the Maine Solid Waste Regulations, and no five year site reviews will be
conduct.

To close the landfill in accordance with the State of Maine Solid Waste Regulations, Chapter 401.6 and
404.5 (effective date may 25, 1989,) a soil landfill cover system has been designed. Permits will not be
reguired for cover construction. The proposed cover for Landfill 1 will consist of the following:

A. 18 inches of well-graded soil with at least 35 percent fines;

-------
B. A final cover of 6 inches of soil suitable to support vegetative cover.

The primary objective of a construction debris landfill cover is to mitigate surface physical hazards and
reduce the impact on groundwater from infiltration through the landfill. Additionally, the soil landfill
cover system will mitigate any potential risk to ecological receptors associated with surface soils at
the site.

Post closure activities would be performed at Landfill 1 for a minimum of ten years. 0 & M reguirements
are minimal. Periodic site inspections and maintenance of the cover (e.g. mowing) are the primary
components of 0 & M for Landfill 1.

Contaminants identified to present or have the potential to present risk to human health and the
environment have been removed from the CAP under a time critical removal action. The rationale for this
removal action was described in the "Time Critical Removal Action Memorandum, Operable Unit 2A, Coal Ash
Pile Site", (AFCEE, 1994). Closure was documented in the "Remedial Action Report, Project Closeout
Report, OU 2, OU 2A, OU 6, OU 7, and Other Sites", (AFCEE, 1995) and in the "Removal Action, Report,
Project Close-out
Report for the PCDA and DBA", (AFCEE, 1996) satisfying the reguirement under Section 19.1 of the FFA.

The State's concurrence in the selected remedy, as described above, should not be construed as the
State's concurrence with any conclusion of law or finding of fact which may be set forth in the Record of
Decision (for OU 2A). The State reserves any and all rights to challenge any such finding of fact or
conclusion of law in any other context.

This concurrence is based upon the State's understanding that the MEDEP will continue to participate in
the Federal Facilities Agreement and in the review and approval of operational, design and monitoring
plans.

The MEDEP looks forward to working with the Department of the Air Force and the USEPDA to resolve the
environmental problems posed by this site. If you need additional information, do not hesitate to
contact myself or Mark Hyland.

Sincerely,

pc: Mark Hyland, MEDEP
Mike Nalipinski, EPA
Hank Lowman, BCA

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