EPA Siiperfund
Record of Decision:
PB96-963706
EPA/ROD/R01-96/123
November 1996
Loring Air Force Base,
Operable Unit 4, Limestone, ME
9/30/1996
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Final
Operable Unit 4 (OU 4)
Record of Decision
September 1996
The
Air Force
Rebuilding Our
Environment
Installation Restoration Program
Loring Air Force Base, Maine
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FINAL
Loring Air Force Base
Operable Unit 4 (OU 4)
Record of Decision
September 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 37831-7606
Contractor: ABB Environmental Services, Inc.
Portland, Maine 04101
Job No. 8741-16
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OPERABLE UNIT 4 RECORD OF DECISION
LORING AIR FORCE BASE, MAINE
TABLE 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 ACnVITIES 2-1
2.1 LAND USE AND SITE HISTORY 2-1
2.2 RESPONSE AND ENFORCEMENT HISTORY 2-3
3.0 COMMUNITY PARTICIPATION 3-1
4.0 SCOPE AND ROLE OF OPERABLE UNIT OR RESPONSE
ACTION 4-1
5.0 SUMMARY OF SITE CHARACTERISTICS 5-1
6.0 SUMMARY OF SITE RISKS 6-1
6.1 HUMAN HEALTH RISK ASSESSMENT 6-2
6.1.1 Landfill 1 6-2
6.1.2 Landfill 2 6-2
6.1.3 Landfill 3/Coal Ash Pile 6-6
6.1.4 Chapman Pit Debris Area 6-8
6.2 UNCERTAINTY EVALUATION 6-8
6.3 CONCLUSION 6-10
7.0 DEVELOPMENT AND SCREENING OF ALTERNATIVES 7-1
7.1 STATUTORY REQUIREMENTS/RESPONSE OBJECTIVES 7-1
7.2 TECHNOLOGY AND ALTERNATIVE DEVELOPMENT AND
SCREENING 7-2
8.0 DESCRIPTION OF ALTERNATIVES 8-1
8.1 No ACTION 8-1
8.2 MINIMAL ACTION .'. 8-2
8.3 GROUNDWATER COLLECTION/TREATMENT/DISCHARGE 8-3
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OPERABLE UNIT 4 RECORD OF DECISION
LORING AIR FORCE BASE, MAINE
TABLE OF CONTENTS
(Continued)
Section Title Page No.
9.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF
ALTERNATIVES 9-1
9.1 EVALUATION CRITERIA USED FOR DETAILED ANALYSIS 9-1
9.1.1 Threshold Criteria 9-1
9.1.2 Primary Balancing Criteria 9-1
9.1.3 Modifying Criteria 9-2
9.2 SUMMARY OF COMPARATIVE ANALYSIS 9-3
9.2.1 Overall Protection of Human Health and the
Environment 9-3
9.2.2 Compliance with Applicable or Relevant and
Appropriate Requirements 9-3
9.2.3 Long-term Effectiveness and Permanence 9-3
9.2.4 Reduction of Mobility, Toxicity, or Volume through
Treatment 9-5
9.2.5 Short-term Effectiveness 9-5
9.2.6 Implementability 9-5
9.2.7 Cost 9-5
9.2.8 State Acceptance 9-6
9.2.9 Community Acceptance 9-6
10.0 THE SELECTED REMEDY 10-1
10.1 ACTION LEVELS 10-1
10.2 DESCRIPTION OF REMEDIAL COMPONENTS 10-6
11.0 STATUTORY DETERMINATIONS 11-1
ll.l THE SELECTED REMEDY is PROTECTIVE OF HUMAN
HEALTH AND THE ENVIRONMENT 11-1
11.2 THE SELECTED REMEDY ATTAINS ARARs 11-2
11.3 THE SELECTED REMEDIAL ACTION is COST-EFFECTIVE 11-2
11.4 THE SELECTED REMEDY UTILIZES PERMANENT SOLUTIONS
AND ALTERNATIVE TREATMENT OR RESOURCE RECOVERY
TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE .. 11-4
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OPERABLE UNIT 4 RECORD OF DECISION
LORING AIR FORCE BASE, MAINE
TABLE OF CONTENTS
(Continued)
Section Title Page No.
11.5 THE SELECTED REMEDY DOES NOT SATISFY THE
PREFERENCE FOR TREATMENT WHICH PERMANENTLY AND
SIGNIFICANTLY REDUCES THE TOXICITY, MOBILITY OR
VOLUME OF THE HAZARDOUS SUBSTANCES AS A PRINCIPAL
ELEMENT 11-5
12.0 DOCUMENTATION OF NO SIGNIFICANT CHANGES 12-1
13.0 STATE ROLE 13-1
GLOSSARY OF ACRONYMS AND ABBREVIATIONS
REFERENCES
APPENDICES
APPENDIX A - TRANSCRIPT OF THE PUBLIC MEETING
(JUNE 11, 1996)
APPENDIX B - RESPONSIVENESS SUMMARY
APPENDIX C - LETTER OF CONCURRENCE
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OPERABLE UNIT 4 RECORD OF DECISION
LORING AIR FORCE BASE, MAINE
LIST OF FIGURES
Figure Title Page No.
1-1 Location of OU 4 Sites 1-2
10-1 Compliance and Institutional Control Boundaries 10-7
10-2 Interpreted Water Table and Groundwater Monitoring Wells 10-11
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OPERABLE UNIT 4 RECORD OF DECISION
LORING AIR FORCE BASE, MAINE
LIST OF TABLES
Table Title Page No.
6-1 Contaminants of Concern for Landfill 1 6-3
6-2 Chemicals of Concern for Landfill 2 6-5
6-3 Contaminants of Concern for Landfill 3/Coal Ash Pile 6-7
6-4 Contaminants of Concern for Chapman Pit Debris Area 6-9
6-5 Quantitative Risk Summary 6-11
9-1 Comparative Summary of Remedial Alternatives 9-4
10-1 LF-2 Bedrock Groundwater Action Levels 10-2
10-2 LF-3 Bedrock and Overburden Groundwater Action Levels 10-3
10-3 Groundwater Action Levels and Risk Summary 10-4
11-1 Chemical-Specific ARARs, Criteria, Advisories, and Guidance
Minimal Action Alternative 11-3
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DECLARATION
DECLARATION FOR THE RECORD OF DECISION
SITE NAME AND LOCATION
Operable Unit 4 (OU 4) addresses groundwater associated with Landfill 1 (LF-1),
Landfill 2 (LF-2), Landfill 3 (LF-3), the Coal Ash Pile (CAP), and Chapman Pit
Debris Area (CPDA) at the former Loring Air Force Base (LAFB), located in
Aroostook County, Maine.
STATEMENT OF BASIS AND PURPOSE
This decision document presents the final remedies for OU 4:
• No Further Action (NFA) for groundwater associated with LF-1 and
the CPDA
• Minimal Action for groundwater associated with LF-2 and LF-3/CAP,
in conjunction with the source control remedy selected for LF-2 and
LF-3 as described in the OU 2 Record of Decision (ROD) (ABB
Environmental Services, Inc., [ABB-ES], 1994b).
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 Substances Pollution
Contingency Plan (NCP). This decision is based on the administrative record for
OU 4, which was developed in accordance with Section 113(k) of CERCLA, and is
available for public review at the Air Force Base Conversion Agency, 5100 Texas
Road, Limestone, Maine. Through the combined source control remedy for OU 2
(ABB-ES, 1994b) and this groundwater mitigation remedy for OU 4, the U.S. Air
Force (USAF) plans to remedy the threat to human health posed by the presence of
contaminated groundwater at LF-2 and LF-3/CAP.
The Maine Department of Environmental Protection (MEDEP), concurs with the
selected remedy for OU4.
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DECLARATION
ASSESSMENT OF OU 4
The USAF has determined that NFA is necessary for the groundwater associated
with LF-1 and the CPDA, since risk estimates for domestic use of groundwater are
below U.S. Environmental Protection Agency (USEPA) target risk levels. Risks
associated with bedrock groundwater at LF-1 exceed the MEDEP cancer risk
guidance value of IxlO"5. However, a soil cover system has been installed as required
by Maine State Solid Waste Regulations.
Actual or potential releases of hazardous substances from LF-2 and LF-3/CAP, if not
addressed, may pose a risk to human health and the environment. This risk will be
addressed by implementing the Minimal Action groundwater remedy selected in this
ROD, in conjunction with the source control remedy outlined in the OU 2 ROD.
DESCRIPTION OF THE SELECTED REMEDY
The USAF has determined that NFA is appropriate for groundwater associated with
LF-1 and the CPDA.
The selected remedy for groundwater associated with LF-2 and LF-3/CAP is
Minimal Action. In addition to the low permeability cover systems, 30-year landfill
post-closure monitoring, and deed restrictions for Landfill 2 and Landfill 3 contained
in the OU 2 ROD, implementation of the OU 4 Minimal Action alternative would
include the following activities:
• institutional controls;
• groundwater monitoring;
• five-year site reviews; and
• contingency action, if necessary.
If results of monitoring show landfill-related contaminants are detected at the
compliance point at concentrations above the action levels, a contingency action will
be implemented. The contingency action is discussed in Subsection 10.2 of this
ROD.
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DECLARATION
STATUTORY DETERMINATIONS
The statutory requirements of CERCLA Section 121 for remedial actions are not
applicable to the NFA decision for groundwater associated with LF-1 and the CPDA.
Therefore, no five-year review will be undertaken for these sites.
The remedy selected by the USAF for LF-2 and LF-3/CAP is protective of human
health and the environment, complies with applicable or relevant and appropriate
requirements (ARARs) for this action, and is cost-effective. This remedy uses
permanent solutions and alternative treatment technologies to the extent practicable.
The selected remedy does not, however, satisfy the statutory preference for remedies
that employ treatment that reduces toxicity, mobility, or volume as a principal
element. Mobility of contaminants is expected to be reduced through the
containment features of the landfill cover systems under OU 2, which will also reduce
rainwater infiltration, leachate generation, and associated groundwater contamination.
Institutional controls will restrict human exposure to contaminated groundwater in
the vicinity and downgradient of the landfills.
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DECLARATION
DECLARATION
This ROD represents NFA under CERCLA for LF-1 and the CPDA and the
selection of a remedial action under CERCLA for LF-2 and LF-3/CAP. The
forgoing represents the selection of a remedial action by the Department of the Air
Force and the United States Environmental Protection Agency Region I with the
concurrence of the Maine Department of Environmental Protection.
Concur and-recommend for Jmmediate implementation:
Date:
Alan K. Olsen
Director
Air Force Base Conversion Agency
United States Environmental Protection Agency
By: g^lU^ SSJ< S/t^yzS Date:
Hrfda M. Murphy x ^
Director
Office of Site Remediation and Restoration
Region I
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SECTION 1
1.0 SITE NAME, LOCATION AND DESCRIPTION
The former 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
west by the City of Caribou. The base is approximately 3 miles west of the United
States/Canadian border and covers approximately 9,000 acres.
LAFB is a NPL site. There are currently several areas of concern under
investigation within LAFB, which have been organized into Operable Units (OUs)
for investigation and remediation purposes. This ROD relates to OU 4, which
consists of groundwater associated with LF-1, LF-2, LF-3, the CAP, and the CPDA.
Soils/sources for LF-2 and LF-3 were addressed under OU 2; soils/sources for LF-1
and the CAP were addressed under OU 2A; and soils/sources for the CPDA were
addressed under OU 3. Figure 1-1 shows the location of the five OU 4 sites and
their relationship to features at the western boundary of LAFB.
Landfill 1. LF-1 covers approximately 3.3 acres and is located in the southwestern
part of the base west of West Virginia Road and north of Green Pond. Site features
have changed since the Remedial Investigation (RI) as a result of grubbing and
grading in preparation for cover system construction. For more detailed information
on LF-1, including pre-construction conditions, see Section 7.1 of the OU 4 RI
Report (ABB-ES, 1995) and the OU 2A ROD (ABB-ES, 1996a).
Landfill 2. LF-2 covers nine acres approximately one mile west of the West Gate
on Nebraska Road and is surrounded by a densely wooded area. Site features have
changed since the RI as a result of grading during on-going cover system
construction. For more detailed information on LF-2, including pre-construction
conditions, see Section 5.1 of the OU 4 RI Report (ABB-ES, 1995) and the OU 2
ROD (ABB-ES, 1994b).
Landfill 3. LF-3 covers approximately 17 acres, is located on Sawyer Road, about
one half mile southwest of the West Gate, and is approximately 1,000 feet south of
LF-2. Site features have changed since the RI as a result of grading during on-going
cover system construction. For more detailed information, including pre-construction
conditions, see Section 6.1 of the OU 4 RI Report (ABB-ES, 1995) and the OU 2
ROD (ABB-ES, 1994b).
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ILANDFILL 21
RGUREH
LOCATION OF
OU 4 SITES
0 500 1000 2000 FEET
LORING AIR FORCE BASE
LIMESTONE, MAINE
SCALE: 1" = 1000'
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SECTION 1
Coal Ash PUe. The CAP was located northeast of LF-3 and south of Nebraska Road,
about one-half mile southwest of the West Gate. The CAP consisted of three
distinct areas where uniform types of waste were identified. These areas have been
provided unofficial names to allow them to be distinguished from one another. They
are the Coal Ash Disposal Area (CADA), the Drum Disposal Area (DDA), and the
Paint Can Disposal Area (PCDA). These three disposal areas combined occupied
five acres: The CADA is 4.1 acres; the DDA is 0.9 acres; and the PCDA is less
than 0.1 acres. For more detailed information, see Section 6.1 of the OU 4 RI
Report (ABB-ES, 1995) and the OU 2A ROD (ABB-ES, 1996a).
Chapman Pit Debris Area. The CPDA is located approximately 500 feet west of
LF-1, south of Chapman Pit Pond. The area is a relatively flat wooded area,
approximately two acres in size. The north side of the debris area is bounded by an
unimproved road and Chapman Pit Pond. The east and south sides of the debris
area slope steeply to wet areas. To the west, the debris area slopes steeply to a small
stream that ultimately drains into Greenlaw Brook. For more detailed information.
see Section 8.1 of the OU 4 RI Report (ABB-ES, 1995) and the OU 3 RI Report
(Law Environmental, Inc. [Law], 1996).
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SECTION 2
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
This section summarizes the land use, response history, and enforcement history for
each of the five OU 4 sites.
2.1 LAND USE AND SITE HISTORY
Landfill 1. Sand and gravel from the LF-1 site was mined for construction at the
base until 1952. The area reportedly was used for base waste disposal from 1952 to
1956. It was suspected that during its operation, the landfill received hazardous
waste generated by flightline activities. However, evidence of such wastes were not
encountered during RI explorations. This waste was reportedly burned and buried
on site (CH2M Hill, 1984). Based on reconnaissance and subsurface exploration
activities, the landfill area contains construction debris including asphalt, concrete
and rebar. The site has been inactive since 1956, although some dumping of
construction debris at the surface was reported to have occurred since that time. A
soil cover system has been designed for LF-1 in accordance with Maine Solid Waste
Regulations. Construction of the soil cover system was completed in 1996.
Landfill 2. The LF-2 area was quarried for gravel during construction of the base.
Waste disposal began in 1956 after the gravel had been exhausted, and continued
until 1974. The landfill was covered with approximately one foot of clean soil and
was closed in 1974. The LF-2 area soils settled over time, leaving a depression in the
LF-2 surface. In 1994 and 1995, nonhazardous contaminated soil and debris from
various removal actions were placed on LF-2 as subgrade for a cover system,
designed in accordance with Resource Conservation and Recovery Act (RCRA)
Subtitle C and Maine Hazardous Waste Regulations, and constructed in 1996.
Wastes buried or burned at the site include: domestic garbage, construction rubble,
flightline wastes, and sewage sludge. There are no records of waste segregation at
the landfill and waste was reportedly distributed evenly. Flightline wastes disposed
of at this site reportedly included oil, hydraulic fluids, solvents, thinners, and paints.
Disposal of hazardous substances at this site reportedly ended by 1968. No
additional information is available concerning daily operations at LF-2 or the burial
locations of different types of waste.
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SECTION 2
In accordance with the response action specified in the OU 2 ROD (ABB-ES,
1994b), the selected source control remedial action for LF-2 is containment using a
low permeability cover system. The cover system has been designed in accordance
with RCRA Subtitle C and Maine Hazardous Waste Regulations. Site preparation
for the cover system began in 1994, and the cover system was completed in 1996.
Landfill 3. The area occupied by LF-3 was quarried extensively for gravel during
construction of the airfield runway and the Fligbtline Area. Gravel quarrying
continued as late as 1994 in the northwestern portion of the site. The landfill
received waste from 1974 to 1991, and eventually was covered with six inches of
native soil. Between 1994 and 1996, nonhazardous contaminated soil and debris
from various removal actions were placed on LF-3 as subgrade for a cover system.
Waste brought to this site included base refuse such as domestic garbage, contents
of dumpsters from the flightline shops, and mess hall wastes. Hazardous wastes are
not known to have been placed at LF-3. However, it is suspected that small
quantities of hazardous substances such as partially-filled solvent cans, oily-water
wastes, and fuel-saturated soil are buried at this landfill. No additional information
about daily operations at LF-3 is available.
In accordance with the response action specified in the OU 2 ROD (ABB-ES,
1994b), the selected source control remedial action for LF-3 is containment using a
low permeability cover system. The cover system has been designed in accordance
with RCRA Subtitle C and Maine Hazardous Waste Regulations. Site preparation
for the cover system began in 1994 and the cover system scheduled to be completed
in 1998.
Coal Ash Pile. The CAP was used as a source of gravel during base construction.
Following depletion of the gravel in this area, the excavation appeared to have been
filled with coal ash and some construction debris. The time period during which the
CAP was active is not known. According to the "Master Plan for Limestone AFB"
dated 1957, coal ash had been dumped in an abandoned gravel pit outside the West
Gate during the early 1950s.
Coal ash generated from industrial and domestic sources comprised most of the
waste in the CAD A, along with some construction debris. The PCDA was located
south of the CADA and the DDA. Although it is not known how long this disposal
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SECTION 2
area was active, paint cans are the only wastes known to have been disposed of at
this location.
The CAP was eliminated in a removal action conducted in 1994 and 1995.
Approximately 184,000 cubic yards of coal ash, contaminated soil, concrete rubble,
and miscellaneous debris and refuse were removed from the area and placed at LF-2
and LF-3 as subgrade material for the cover systems.
Chapman Pit Debris Area. The CPDA was previously mined for sand and gravel
during construction of the base. After mining activities ceased, an earthen dam was
constructed across the southern portion of the pit, creating Chapman Pit Pond north
of the dam. During construction of the dam, fill was deposited in the southern
portion of the pit (i.e., CPDA), and unauthorized dumping may have occurred (Law,
1996).
Bituminous asphalt and concrete materials were reportedly disposed of in this area.
Equipment and construction supplies may also have been placed in the pit and
covered over with fill. Small amounts of household and construction debris were
encountered during field investigations, but there is no evidence of widespread debris
dumping.
22 RESPONSE AND ENFORCEMENT HISTORY
The response and enforcement history of OU 4 sites is summarized as follows:
• In 1984, a Preliminary Assessment (PA) was completed detailing
historical hazardous material usage and waste disposal practices at
LAFB (CH2M Hill, 1984).
• Initial Site Investigation (SI) field work was conducted in 1985 to
determine if contaminants were present at the OU 4 sites (Weston,
1988).
• The RI process commenced in 1988 and continued into 1994 (ABB-ES,
1995).
• LAFB was added to the NPL in February 1990.
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SECTION 2
• The USAF entered into a Federal Facilities Agreement (FFA) (FFA,
1991) with the USEPA and MEDEP in 1991, to address the cleanup
of environmental contamination at LAFB. The FFA was revised in
December 1993 to address base closure related issues, such as real
estate property transfer, and to revise the cleanup schedule. The FFA
was further modified in January 1995 to allow the Remedial Project
Managers to make minor modifications, such as schedule adjustments
and removal of petroleum-contaminated sites from the agreement.
• A Feasibility Study (FS) (ABB-ES, 1996b) was completed in 1996 for
OU 4 to determine remedial alternatives for LF-2 and LF-3 based on
information presented in the RI report; and
• A Proposed Plan (ABB-ES, 1996c) was submitted for public review in
May 1996.
• Public comment period from May 17, 1996 to June 15, 1996.
The following additional key milestones at LAFB indirectly relate to OU 4:
• Non-hazardous contaminated soils from other sites on base were
excavated and placed on LF-2 and LF-3 in 1994 and 1995 as subgrade
material for the cover systems. LF-3 will receive non-hazardous
contaminated soils from other sites on base in 1996 and 1997.
• A removal action was conducted at the CAP in 1994 and 1995 in which
excavated materials were placed at LF-2 and LF-3 as subgrade
material for the cover systems.
• Construction of a soil cover system at LF-1 was completed in 1996.
• Construction of LF-2 cover system was completed in 1996.
• Construction of LF-3 cover system is scheduled for completion in 1998.
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SECTION 3
3.0 COMMUNITY PARTICIPATION
Throughout LAFB's history, the community has been active and involved in base
activities at a high level. The USAF and USEPA 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, as well as
Restoration Advisory Board (RAB) meetings. The RAB is chaired by USAF 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 USAF made the LAFB Administrative Record available for
public review. The Administrative Record is currently available for public review at
the Air Force Base Conversion Agency Office, 5100 Texas Road, Limestone, Maine.
The USAF published a notice and brief analysis of the OU 4 Proposed Plan in the
Bangor Daify News, the Aroostook Republican, and the Fort Fairfield Review on
May 15, 1996, and made the Proposed Plan available to the public at the Air Force
Base Conversion Agency Office.
From May 17, 1996 through June 15, 1996, the USAF held a 30-day public comment
period to accept public input on the alternatives presented in the FS and the
Proposed Plan, as well as other documents previously released to the public. On
June 11, 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 as Appendix A, and a Responsiveness Summary is included as
Appendix B. The Air Force received no verbal or written comments on the OU 4
Proposed Plan at a public hearing held on June 11, 1996, or during the 30 day public
comment period.
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SECTION 4
4.0 SCOPE AND ROLE OF OPERABLE UNIT OR RESPONSE ACTION
The USAF has determined that NFA under CERCLA is appropriate for groundwater
associated with LF-1 and the CPDA. The concentrations of organic and inorganic
compounds detected in groundwater at these sites do not pose risks in exceedance
of USEPA target risk levels. A determination by the USAF not to pursue further
action under CERCLA for groundwater associated with LF-1 and the CPDA is not
a determination that no action is warranted for source control under other
regulations and statutes. The State of Maine's statutory authority is not limited by
NFA under CERCLA. A soil cover system at LF-1, in accordance with Maine Solid
Waste Management Regulations, was completed in 1996.
The selected remedy for LF-2 and LF-3/CAP was developed by combining
components of source control and groundwater mitigation alternatives to obtain a
comprehensive approach for groundwater remediation. The selected remedy for
groundwater associated with LF-2 and LF-3/CAP is Minimal Action in conjunction
with the source control remedy for LF-2 and LF-3 as outlined in the OU 2 ROD
(ABB-ES, 1994b). In addition to the low permeability cover systems, 30-year landfill
post-closure monitoring, and deed restrictions for LF-2 and LF-3 contained in the
OU2 ROD, implementation of the selected alternative for OU 4 would include the
following activities:
• institutional controls;
• groundwater monitoring;
• five-year site reviews; and
• contingency action, if necessary (see Subsection 10.2).
The Minimal Action alternative utilizes institutional controls to protect against
human exposure to contaminated groundwater. Groundwater monitoring will be
used to assess contaminant migration and to measure performance of the OU 2 cover
systems in reducing leacbate generation and associated groundwater contamination.
The combination of OU 2 cover systems and application of activities under OU 4
Minimal Action remedy will achieve the following remedial response objectives for
groundwater at LF-2 and LF-3/CAP:
• prevent human exposure to contaminated groundwater, and
• protect downgradient groundwater from contamination.
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SECTION 5
5.0 SUMMARY OF SITE CHARACTERISTICS
Section 2.0 of the FS (ABB-ES, 1996b) contains an overview of the OU 4 RI at LF-2
and LF-3/CAP, including discussions on the geology, hydrogeology, and nature and
distribution of contaminants. The RI Report (ABB-ES, 1995) gives the results of the
investigations at all five OU 4 sites. The significant findings of the RI are
summarized below.
Landfill 1. The site geology at LF-1 is characterized by fill material consisting of
landfill waste and granular soil, ablation till underlain by ice-contact deposits, basal
till, and bedrock consisting of dark gray, pellitic limestone. The ablation till, ice-
contact deposits, and basal till consist generally of fine to coarse sands and gravels
with varying amounts of silty materials. In general, the overburden thickness at LF-1
is about 15 feet, but increases significantly toward the southwest portion of the site
due to a steep drop-off in the bedrock surface. The upper 15 feet of bedrock is
typically highly weathered and fractured, but becomes more competent with depth.
Groundwater in the area of LF-1 is interpreted to be flowing to the southwest and
discharging to Green Pond. Downward vertical gradients near the northeastern edge
of the landfill suggest downward groundwater movement, or recharge, in this area.
At the southeastern edge of the landfill near Green Pond, the vertical gradients are
upward, suggesting groundwater discharge into Green Pond.
Upgradient of the landfill, the water table is typically just above the top of the
bedrock surface. The saturated overburden thickness increases steadily to
approximately 40 feet at the downgradient or southwestern edge of the landfill. The
increase in saturated thickness is a function of the rapid drop in the bedrock surface
across the site from northeast to southwest. It does not appear that overburden
groundwater extends into the landfill debris, with the possible exception of the toe
of the landfill.
A comparison of upgradient and downgradient groundwater samples does not suggest
an impact on groundwater from the landfill. Landfill leachate parameters indicated
no change in groundwater conditions upgradient to downgradient. Manganese and
aluminum were the only inorganics reported above maximum exposure guidelines
(MEGs) for unfiltered analyses; however, no exceedances of MEGs or MCLs were
noted in low-flow samples collected subsequent to the RI (ABB-ES, 1996b). Vinyl
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chloride was detected twice in one well at concentrations exceeding maximum
contaminant levels (MCLs)/MEGs.
Landfill 2. LF-2 geology is characterized as glaciofluvial, with associated deposits
consisting of ablation till underlain by ice-contact deposits, a discontinuous layer of
basal till, and dark gray, weathered, pellitic limestone. Overburden thickness ranges
from negligible in the central'area of the landfill to about 60 feet at the northwestern
portion of the site, outside the area of landfilled wastes. In most cases, landfilled
wastes were placed on ice-contact deposits; however, they were also placed directly
on the bedrock surface in some areas.
Based on interpretive bedrock contours, it appears that a northwest to southeast
trending bedrock trough exists beneath LF-2. The topographic high of the trough is
located near the northwestern end of LF-3. The trough plunges northwest in the
vicinity of LF-2.
The bedrock trough beneath LF-2 apparently influences groundwater flow in both
the shallow bedrock and overburden soils. Groundwater flow at LF-2 is to the north-
northwest, subparallel to the trend of the bedrock trough. This direction of flow
indicates that water flowing across LF-2 may also have flowed through the northern
portion of LF-3. Potentiometric head data for two overburden bedrock well pairs
show weak overall upward gradients in the area of LF-2.
The discontinuous shallow overburden aquifer and the fractured-bedrock aquifer
appear to form one groundwater system throughout the LF-2 area, due to the
permeable nature of the sand and gravel, and the weathered and fractured nature of
the bedrock. The water table is located in the overburden soils over the majority of
the LF-2 site. Therefore, it can be concluded that groundwater comes into contact
with some of the waste throughout the year.
Volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs),
pesticides, inorganics above background concentrations, total petroleum hydrocarbons
(TPHs), and oil and grease were detected in groundwater in and around LF-2. In
addition, several miscellaneous parameters which are typical indicators of landfill
plume contamination were detected in groundwater samples collected in 1993 and
1994.
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Contaminants detected in overburden wells inside the landfill perimeter include fuel-
related VOCs and chlorobenzenes, SVOCs (including bis(2-ethylhexyl)phthalate
[BEHP] above the MCL), pesticides, and inorganics. Concentrations of contaminants
detected in perimeter wells completed in the overburden adjacent to or downgradient
from LF-2 were generally lower than concentrations within the limits of the waste.
No significant organic contaminants were detected in overburden groundwater in
perimeter wells.
Based on the most recent sampling results, inorganics above background
concentrations were detected in all bedrock monitoring wells around LF-2. The
SVOC BEHP was detected, and the VOC vinyl chloride was detected above its
MEG, but not in excess of its MCL. Tetrachloroethene (PCE) was detected above
its MEG but not its MCL. The only inorganics identified as chemicals of potential
concern during low-flow sampling (LFS) were arsenic, barium, iron, and manganese.
Landfill 3/CAP. Because of the proximity of LF-3 and the CAP, these two OU 4
, sites will be discussed concurrently in this section. LF-3/CAP overburden geology
is characterized as a former esker deposit, consisting of ablation till underlain by ice-
contact deposits, and highly weathered, pellitic limestone. Thickness of the soils
outside the landfilled material ranges from about 5 feet on the northern side to a
maximum of 55 feet southeast of the site in the bedrock trough. Wastes appear to
have been placed directly on the ice-contact sand and gravel deposits.
Bedrock in the LF-3/CAP area is a gray pellitic limestone. The northwest-to-
southeast-trending bedrock trough present beneath LF-2 appears to continue beneath
LF-3, narrowing and rising to a saddle in the northwestern area of LF-3, then
deepening again to the southeast of the landfill. Bedrock is interpreted to be more
fractured within the trough axis than on the trough walls.
The water table was typically encountered above the bedrock surface within the
perimeter of LF-3 and the CAP. LF-3 waste appears to be partially saturated by
groundwater throughout the year. The groundwater system is bounded to the east
and west of LF-3 by the bedrock trough, and data indicate that the water table enters
bedrock in the axis of the trough south of LF-3. To the north of the divide,
groundwater flows northward toward LF-2, whereas south of the divide, groundwater
flow is interpreted to be southeast. Calculated vertical gradients suggest that
downward groundwater movement exists on the flanks of the bedrock trough, and
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SECTION 5
limited upward groundwater movement exists in the central areas of the bedrock
trough.
VOCs, SVOCs, pesticides, and inorganics above background concentrations were
detected in groundwater in and around LF-3. Oil and grease were also detected in
groundwater samples collected within the LF-3 boundary during 1993 sampling.
Concentrations of VOCs (including benzene, trichloroethene [TCE], PCE, and vinyl
chloride), SVOCs (including polynuclear aromatic hydrocarbons [PAHs]), and
inorganics (including lead, nickel, and cadmium) were detected above MEGs and/or
MCLs within the LF-3 boundary. The only exceedance for pesticides was heptachlor
in a single well. Concentrations of VOCs, SVOCs, and inorganics are generally
highest in wells within the southern half of the landfill.
Concentrations of contaminants in overburden outside the perimeter of the landfill
were generally much lower than concentrations within the landfill. There were no
exceedances of MEGs and/or MCLs for VOCs and pesticides/polychlorinated
biphenyls (PCBs). Only one SVOC, BEHP, was detected above MEGs and/or
MCLs. Arsenic, barium, iron, and manganese were identified above background
concentrations in overburden groundwater low-flow samples collected outside the
perimeter of the landfill.
VOCs (i.e., PCE, benzene, and vinyl chloride) were detected sporadically above the
MEGs and/or MCLs in bedrock wells, generally south, east, and west of LF-3.
SVOCs have been detected in several bedrock monitoring wells. The only SVOC
concentrations above MCLs or MEGs were for BEHP, which was detected in three
monitoring wells. Pesticides have been detected in most samples, although
concentrations were generally extremely low. No pesticides or PCBs were detected
above MEGs and/or MCLs in wells around LF-3. Inorganics above background
concentrations have been detected in bedrock wells in the vicinity of LF-3.
Chapman Pit Debris Area. The site geology at the CPDA is characterized as fill
material overlying native glacial and post-glacial deposits, which in turn are underlain
by pellitic limestone. The two fill materials present consist of silts, sands, and gravels
placed during LAFB gravel mining activities, and during construction of the dam
after mining activities ceased. The post-glacial deposits consist of peat, silt and clay
pond deposits, and medium to coarse sand and gravel stream channel deposits. The
basal till, a mixture of varying amounts of silt, sand, and clay, lies directly over a
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SECTION 5
highly fractured, pellitic limestone. Overburden thickness ranges from 10 to 20 feet
over much of the site, to as much as 42 feet at the southern boundary of the area.
The groundwater system associated with the CPDA is bounded to the north by a
recharge boundary (Chapman Pit Pond), to the east, south, and west by unnamed
streams and swamps that act as discharge boundaries. These boundaries are assumed
to control both overburden and bedrock groundwater flow in the CPDA.
Groundwater flow is generally south and southwest away from Chapman Pit Pond.
Organic contaminants at this site are present only at very low concentrations.
Methylene chloride was the only reported VOC at estimated concentrations above
the MCL in 1993 samples, but it was not detected in 1994 samples. BEHP was the
only SVOC detected above its MCL. Metals appear to be the primary constituents
present, with aluminum and manganese consistently exceeding regulatory criteria.
Lead exceeded MEGs in one overburden groundwater sample, but not at a
concentration that would cause exceedance of the blood lead level, which would
cause risk.
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SECTION 6
6.0 SUMMARY OF SITE RISKS
A baseline human health risk assessment (RA) was performed as part of the OU 4
RI Report (ABB-ES, 1995). A revised RA was performed as part of the OU 4 FS
(ABB-ES, 1996b). The revised RA focused on the recalculation of risk based on the
separation of OU 4 groundwater into bedrock and overburden samples for each of
the sites, and the incorporation of LFS results for inorganic analytes, as available.
The assessment was performed in accordance with USEPA guidance documents
(USEPA, 1989a,b,c,d; 1991a,b), MEDEP Guidance Manual (MEDEP/DHS, 1994)
and the Loring Air Force Base Risk Assessment Methodology (Hazardous Waste
Remedial Actions Program [HAZWRAP], 1994). The RA estimates the probability
and magnitude of potential adverse human health effects from exposure to
groundwater contaminants associated with the OU 4 sites. The human health risk
assessment followed a four step process:
1) contaminant identification identified those hazardous substances
which, given the specifics of the site, were of significant concern;
2) exposure assessment identified actual or potential exposure pathways,
characterized the potentially exposed populations, and determined the
extent of possible exposure;
3) toxicity assessment considered the types and magnitude of adverse
health effects associated with exposure to hazardous substances; and
4) risk characterization integrated the three previous steps to summarize
the potential and actual risks posed by hazardous substances at the
site, including carcinogenic and non-carcinogenic risks.
Although groundwater is not currently used on the former base, and residential
development will be restricted, the RA assumed domestic use of groundwater.
Exposure to residual contamination in the groundwater present at or migrating from
the OU 4 sites is assumed to occur through residential use (i.e., drinking, cooking,
washing, and showering). For more detail on the data sets used, contaminant
identification, exposure assessment, toxicity assessment, and risk characterization, see
Section 3 of the Final OU 4 FS (ABB-ES, 1996b).
Installation Restoration Program
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SECTION 6
Carcinogenic and noncarcinogenic risks are quantitatively evaluated for each site.
Carcinogenic risks are compared to the USEPA target carcinogenic risk range of
IxlO"4 to IxlO'6 and the MEDEP cancer risk guidance value of IxlO'5.
Noncarcinogenic risks are compared to the USEPA noncarcinogenic Hazard Index
(HI) of 1.0 (USEPA, 1989a).
6.1 HUMAN HEALTH RISK ASSESSMENT
A summary of the results of the human health risk assessment for LF-1, LF-2, LF-3/
CAP, and the CPDA groundwater is presented in the following subsections and are
tabulated on Table 6-5.
6.1.1 Landfill 1
Risks from exposure to bedrock and overburden groundwater at LF-1 were evaluated
separately. The contaminants of concern identified for each data set are presented
on Table 6-1.
Lead was not detected in either the bedrock or overburden data sets.
LF-1 Bedrock Groundwater. The total cancer risks for the average (i.e., most
probable case) and maximum (i.e. reasonable maximum exposure [RME]) scenarios
are 4xlO~5 and IxlO"4, respectively. These risks exceed the MEDEP cancer risk
guidance value of IxlO"1, but are within the USEPA carcinogenic risk range of 1x10"*
to IxlO4. The noncancer risks are less than an HI of 1. The HI for the average
exposure is 0.02, and for the maxitn\im exposure is 0.06.
LF-1 Overburden Groundwater. The total cancer risks for the average and maximum
scenarios are 7xlO~7 and 1x10*, respectively. These risks are less than the MEDEP
cancer risk guidance value of IxlO"5, and less than the USEPA carcinogenic risk
range of 1x10"* to IxlO4. The noncancer risks are less than an HI of 1. The HI for
the average exposure is 0.006, and the HI for the maximum exposure is 0.009.
6.12 Landfill 2
Risks from exposure to bedrock and overburden groundwater at LF-2 were evaluated
separately. Because of distinct differences in the nature of contamination, shallow
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TABLE 6-1
CHEMICALS OF CONCERN FOR LANDFILL 1
HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4 RECORD OF DECISION
LOFBNG AIR FORCE BASE
Compound
LF-1 BEDROCK GROUNDWATER
Chloroform
Vinyl Chloride
Aluminum
LF-1 OVERBURDEN GROUNDWATER
tais(2-EthylhaxyQphthalato
Minimum
DaMBtad
Conoontrauon
Jmofl.)
0.009
0.00211
0.0641
0.001
Maximum
Conoantraaon Conoantratlon
0.009 0.0027
0X10211 0.000822
0.177 0.09467
0.005 OJ0032S
Fraquanoy
• *» . •
Oetaetioh
1 / 5
1 / 5
S / 5
2 / 2
NOTE: For information on data aata (walk, analyscc. and sampla dataa) uaad in tha RA. aoa Tabla 3-1 of tha Srak Final FS (ABB-ES. 1996a).
6-3
OU4-COC.XLS
8/13/96
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SECTION 6
bedrock (less than 200 feet bgs) and deep bedrock (greater than 200 feet bgs
groundwater were evaluated separately. Similarly, overburden groundwater from
within the landfill boundary was evaluated separately from overburden groundwater
outside the landfill boundary. The contaminants of concern identified for each data
set are presented on Table 6-2.
Lead was detected in the data sets for both shallow and deep bedrock groundwater.
Lead was evaluated using the Integrated Exposure Uptake Biokinetic (IEUBK)
Model only in the data set for deep bedrock, where concentrations exceeded the
USEPA Action Level of 15 micrograms per liter (fig/L). IEUBK results indicate
that blood lead levels due to consumption of lead at both average and maximum
concentrations in drinking water would exceed the USEPA guidance blood lead level
of 10 micrograms per deciliter (jtg/dL).
LF-2 Shallow Bedrock Groundwater. The total cancer risks for the average and
maximum scenarios are IxlO"4 and 2x10"*, respectively. These risks exceed the
MEDEP cancer risk guidance value of IxlO"5. The maximum exposure risk exceeds
the USEPA carcinogenic risk range of IxlO"4 to 1x10"*, and the average risk equals
the upper end of the risk range. The primary contributors to the carcinogenic risk
are arsenic, vinyl chloride, and 2,6-dinitrotoluene. The noncancer risks exceed an HI
of 1. The HI for both the average and maximum exposure scenario is 3. The
primary contributors to the noncancer risk are manganese, iron, and arsenic.
LF-2 Deep Bedrock Groundwater. The total cancer risks for the average and
maximum scenarios are 6xlO~5 and IxlO4, respectively. These risks exceed the
MEDEP cancer risk guidance value of IxlO*5, but are within the USEPA carcinogenic
risk range of IxlO"4 to IxlO4. The primary contributor to the carcinogenic risk is
arsenic. The noncancer risks exceed an HI of 1. The HI for the average exposure
is 5, The HI for the maximum exposure is 9. The primary contributors to the
noncancer risk are iron, cadmium, and zinc.
LF-2 Overburden Groundwater Outside the Perimeter of the Landfill. The total
cancer risks for the average and maximum scenarios are 6x10"* and IxlO"5,
respectively. These risks are less than or equal to the MEDEP cancer risk guidance
value of IxlO"5, and within the USEPA carcinogenic risk range of 1x10"* to IxlO4.
The noncancer risks are less than an HI of 1. The HI for both the average and
maximum scenario is 0.1.
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TABLE 6-2
CHEMICALS OF CONCERN FOR LANDFILL 2
HUMAN HEALTH RISK ASSESSMENT
OPERABLE UMT 4 RECORD OF DECISION
LOMNQ AIR FORCE BASE
Compound
LF-2 SHALLOW BEDROCK OROUNDWATER «2OO' ba<)
<•. - -LI -L
TatrMnlOfuaUiai la
Vinyl Chlorida
ola-1 ,2-Diehloraatrwia
1 ,2.4 Triohtorobaniana
2.0-Oinitratoluana
bM2-Ethylhaxyl)phthalata
Araante
Barium
Iron
Manganaaa
LF-2 DEEP BEDROCK OROUNDWATER O2001 bo>)
bia(2-Ethylhaxyliphthalata
Aluminum
AiMnie
Barium
Cadmium
Chromium
Iron.
Laad
Manganaaa
Zinc
LF-2 OVERBURDEN OROUNDWATER OUTSIDE THE PERI
Vinyl Chlorida
bto(2-Ethylhaxvl|phthalata
Barium
Manoanaaa
LF-2 OVERBURDEN OROUNDWATER INSIDE THE PERUM
Banzana
Chlonbanzana
Vinyl Chloride
b»(2-€thylhaxYl|prrthalata
DMdrin
HaptaoMor
Barium
Manganaaa
AjBlAtMMtk
Oataotad
Comwntration
tow/1.)
A (TV19
U.UU2
0.00017
0.0007
0.016
0.002
0.011
0.0040
0.128
8.84
1.40
O.OO4
0.0570
O.OO17
0.023
0.0042
0.0107
1.49
0.051
0.0441
4.78
METER OF THE LANDFILL
0.00027
0.003
0.0588
0.144
=TER OF THE LANDFILL
0.001
O.O005
0.002
0.00010
0.003
O.OOOO02
0.000018
O.OS88
0.144
Maximum
Oft*otxj
tmo/U
A AAal
U.^V*V
0.00141
0.0007
0.010
0.002
0.011
0.0040
0.128
0.04
1.40
0.022
2.14
0.0042
0.910
0.0320
0.020
33
0.495
0.38
13
0.00027
0.003
0.0688
0.144
0.001
0.002
0.013
O.O0023
0.01
0.000002
0.00001 B
0.0688
0.144
Maan
Conoantration
ima/U
A AA1 9BA
V.UU 1 aCOD
O.O00351
0.000533
0.000571
0.004671
0.005867
0.0040
0.128
0.04
1.40
0.0125
0.71336
0.002488
0.270176
0.016876
0.013626
16.47
0.185203
0.174725
8.24
0.000111
0.000
0.0688
0.144
0.0000
0.00081
0.0033
O.O00108
0.0072
O.OOO008
0.000000
0.0688
0.144
fn>
Da
4
1
^
4
3
3
4
4
3
4
4
4
4
1
1
1
1
1
3
2
2
3
1
1
1
1
nMftotf
P^P"WJ
or ,
teotton
/ ^
/ /
/ 7
/ 6
/ 7
/ 7
/ 7
/ 1
/ 1
/ 1
/ 1
/ 4
/ 4
/ 4
/ 4
/ 4
/ 4
/ 4
/ 4
/ 4
/ 4
/ 4
/ 4
/ 1
/ 1
/ 6
/ 5
/
/
/
/
/
/ 1
/ 1
NOTE: For Information on data a»1» («»all», analyaa*. and Mmota d«t»») u»»d In tha RA, ••» Tabla 3-1 of tha Ora*> Final FS (ABB-ES. 1990a).
6-5
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SECTION 6
LF-2 Overburden Groundwater Inside the Perimeter of the Landfill. The total
cancer risks for the average and maximum scenario are 9x10* and 2xlO"3, respectively.
Only the maximum exposure risk exceeds the MEDEP cancer risk guidance value of
bclO"5. Both the average and maximum risks are within the USEPA carcinogenic risk
range of IxlO"4 to Ixlfr6. The noncancer risks are less than an HI of 1. The HI for
the average exposure is 0.4, and for the maximum exposure is 0.7.
6.13 Landfill 3/Coal Ash Pile
Risks from exposure to bedrock and overburden groundwater at LF-3/CAP were
evaluated separately. Because of distinct differences in the nature of contamination,
overburden groundwater from within the landfill boundary was evaluated separately
from overburden groundwater outside the landfill boundary. The contaminants of
concern identified for each data set are presented on Table 6-3. Lead was detected
in the bedrock data set at a maximum concentration less than the USEPA Action
Level of 15 /tg/L; therefore, no further evaluation of lead was performed for
LF-3/CAP.
LF-3/CAP Bedrock Groundwater. The total cancer risks for the average and
maximum exposures are 8xlO"5 and 3x10"*, respectively. These risks exceed the
MEDEP cancer risk guidance value of IxlO"3, and the maximum exposure risk
exceeds the USEPA carcinogenic risk range of 1x10"* to 1x10^. The priman
contributors to the carcinogenic risks are arsenic, vinyl chloride, and heptachlor. The
noncancer risks equal or exceed an HI of 1. The HI for the average exposure is 1.
and the HI for the maximum exposure is 6. The primary contributors to the
noncancer risks are iron and manganese.
LF-3/Cap Overburden Groundwater Outside the Perimeter of the Landfill. The
total cancer risk for both the average and maximum exposure is 4x10"*. This risk
exceeds the MEDEP cancer risk guidance value of lx!0~s, and the USEPA
carcinogenic risk range of 1x10"* to IxlO"6. The only contributor to the carcinogenic
risk is arsenic. The noncancer risks exceed an HI of 1. The HI for both the average
and the maximum scenario is 7. The primary contributors to the noncancer risk are
iron, arsenic, and manganese.
LF-3/CAP Overburden Groundwater Inside the Perimeter of the Landfill. The total
cancer risk for both the average and maximum exposure is 5xlO~*. This risk exceeds
the MEDEP cancer risk guidance value of IxlO"5, and the USEPA carcinogenic risk
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W0039621.060 8741-16
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TABLE 6-3
CHEMICALS OF CONCERN FOR LANDFILL 3/COAL ASH PILE
HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4 RECORD OF DECISION
LORINQ AIR FORCE BASE
Compound
LF-3/CAP BEDROCK OROUNDWATER
Benzene
Vinyl Chloride
bis(2-Ethylhexyl)phthalate
Haptaohlor
Heptachlor Epoxide
Aluminum
Arsenic
Copper
Iron
Manganese
Minimum
Detected
Concentration
Ifna/L)
0.003
0.0005
0.001
0.000072
0.000001
O.S33
0.0026
0.0048
0.0911
0.0077
Maximum
Detected
Concentration
(mg/U
0.003
0.00246
0.007
0.000072
0.000001
1.41
0.0062
0.124
22.7
2.78
Mean
Concentration
(mo/U
0.000727
0.00046
0.005136
0.000012
0.000004
0.283383
0.002183
0.013075
3.430533
0.3241
Frequency
«}
Detection
1 / 11
3 / 11
6 / 11
1 / 10
3 / 10
2/12
5 / 12
2 / 12
8 / 12
12 / 12
LF-3/CAP OVERBURDEN OROUNDWATER OUTSIDE THE PERIMETER OF THE LANDFILL
Arsenic
iarium
Iron
Manganese
0.018
0.337
23.2
2.40
0.018
0.337
23.2
2.46
0.018
0.337
23.2
2.46
1 / 1
1 / 1
1 / 1
1 / 1
LF-3/CAP OVERBURDEN OROUNDWATER INSIDE THE PERIMETER OF THE LANDFILL
1,1-Dichloroethane
1 ,4-Dichlorobenzone
!-Butanone
Benzene
'etraohloroethene
Toluene
'riohloroethene
Vinyl Chloride
cie-1 ,2-DicNoroethene
4-Methylphenol
Acenaphthana
Naphthalene
Arsenic
Iron
Manganese
0.003
0.006
0.017
0.011
O.OO4
0.25
0.007
0.00084
0.014
0.05
0.002
0.017
0.018
23.2
2.46
0.053
0.042
7.5
0.011
0.004
1.8
0.066
0.00084
0.22
2
0.002
0.082
0.018
23.2
2.46
0.053167
0.055333
3.51675
0.052583
0.051417
0.677583
0.056
0.000203
0.082833
0.7825
0.132417
0.12525
0.018
23.2
2.46
2 / 6
3 / 6
4/4
1 / 6
1 / 6
5 / 6
2 / 6
1 / 6
2 / 6
4 / 6
1 / 6
3 / 6
1 / 1
1 / 1
1 / 1
NOTE: For information on data «ett (walla, analyaei, and aample datea) used in the RA, aee Table 3-1 of the Graft-Final FS (ABB-ES. 1996a).
6-7
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SECTION 6
range of IxlO"4 to 1x10*. The primary to the carcinogenic risk are arsenic, vinyl
chloride, 1,4-dichlorobenzene, TCE, benzene, and PCE. The noncancer risks exceed
an HI of 1. The HI for the average exposure is 16, and for the maximum exposure
is 27. The primary contributors to the noncancer risk are 4-methylphenol, iron,
benzene, arsenic, manganese, and cis-l,2-dichloroethene (DCE).
6.1.4 Chapman Pit Debris Area
Risks from exposure to bedrock and overburden groundwater at the CPDA were
evaluated separately. The contaminants of concern identified for each data set are
presented on Table 6-4.
Lead was detected in the bedrock data set at a maximum concentration less than the
USEPA Action Level of 15 /*g/L; therefore, no further evaluation of lead was
performed for the CPDA.
CPDA Bedrock Groundwater. The total cancer risks for the average and maximum
exposures are 1x10* and 2x10"*, respectively. These risks are less than the MEDEP
cancer risk guidance value of IxlO"5, and within the USEPA carcinogenic risk range
of 1x10"* to 1x10"*. The noncancer risks are less than an HI of 1. The HI for the
average exposure is 0.4, and the HI for the maximum exposure is 0.7.
CPDA Overburden Groundwater. The total cancer risks for the average and
maximum exposures are IxlO4 and 3x10*, respectively. These risks are less than the
MEDEP cancer risk guidance value of IxlO"5, and within the USEPA carcinogenic
risk range of IxlO4 to 1x10*. The noncancer risks are less than an HI of 1. The HI
for the average scenario is 0.01, and the HI for the maximum exposure scenario is
0.02.
62 UNCERTAINTY EVALUATION
Quantitative estimates of risk are based on numerous assumptions, most of which are
intended to be protective of human health (i.e., conservative). A summary of
potential sources of uncertainty, and the likely tendency of their effects (i.e., to over-
or underestimate risks) is presented in the Final OU4 FS (ABB-ES, 1996b).
Although some uncertainties in the RA methodology might bias the evaluation in the
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TABLE 6-4
CHEMICALS OF CONCERN FOR CHAPMAN PIT DEBRIS AREA
HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4 RECORD OF DECISION
LORINO AIR FORCE BASE
Minimum
Detected
Compound Concentration
Imo/L)
CPDA BEDROCK QROUNDWATER
bit(2-Ethylhexyl)phthalate 0.002
Aluminum 1.12
Iron 0.41 1
Manganese 0.0968
Nickel 0.0173
CPDA OVERBURDEN QROUNDWATER
Methylene Chloride 0.0031
Di-n-butylphthalate 0.00052
bi«(2-Ethylhexyl)phthalate 0.00094
Maximum
Detected
Concentration
fmg/L)
0.007
1.12
1.58
0.513
0.0173
0.0079
0.0019
0.005
Mem
Concentration
Irrm/U
0.0045
0.64525
0.9955
0.3049
0.01275
0.004525
0.002327
0.002723
Frequency
of
Detection
2 / 2
1 / 2
2 / 2
2 / 2
1 / 2
4 / 8
4 / 6
e / e
NOTE: For information on data eeti (wellt, analyaea. and temple datea) uted in the RA. aee Table 3-1 of the Draft-Final FS (ABB-ES, 1996a).
6-9
OU4-COC.XLS
6/13/96
-------
SECTION 6
direction of an underestimation of risk, most assumptions will bias the evaluation in
the direction of overestimation of risk.
6.3 CONCLUSION
A summary of quantitative risks for each of the OU 4 sites is presented on Table 6-5.
Landfill 1 and Chapman Pit Disposal Area. The risk estimates for domestic use of
both overburden and bedrock groundwater at LF-1 and the CPDA are below
MEDEP and USEPA carcinogenic and noncarcinogenic target risk levels, with the
exception of bedrock groundwater at LF-1 which exceeds the MEDEP cancer risk
guidance value. Although risks associated with groundwater at LF-1 are within the
USEPA risk range of 1x10"* to 1x10*, a soil cover system is being installed in 1996
as required by the MEDEP Solid Waste Management Regulations. For these
reasons, the USAF has proposed NFA under CERCLA for LF-1 and the CPDA.
landfill 2. At LF-2, the noncarcinogenic risk estimates for domestic use of bedrock
groundwater exceed an HI of 1.0. The maximum exposure carcinogenic risk for
shallow bedrock groundwater exceeds the MEDEP and USEPA target risk levels.
The average exposure for shallow bedrock exceeds the MEDEP cancer risk guidance
value and equals the upper end of the USEPA target risk range. Both average and
maximum exposures for deep bedrock groundwater, exceed the MEDEP and USEPA
target risk levels. Detections of lead in bedrock groundwater were qualitatively
evaluated using the IEUBK Model, which indicated that blood lead levels due to
consumption of lead at both average and nigirimuin concentrations in drinking water
would exceed the USEPA guidance blood lead level of 10 pg/dL, No remedial
alternatives were evaluated in the FS for overburden groundwater, because risks do
not exceed MEDEP and USEPA target levels, with the exception of overburden
groundwater inside the perimeter of the landfill where the maximum exposure risk
slightly exceeds the MEDEP cancer risk guidance value. For bedrock groundwater,
five remedial alternatives were developed and screened, and the No Action, Minimal
Action, and Groundwater Collection/Treatment/Discharge alternatives were carried
through detailed analysis in the FS.
Landfill 3/Coal Ash Pile. At LF-3/CAP, both average and maximum exposure risk
estimates for domestic use of overburden groundwater exceed MEDEP and USEPA
carcinogenic and noncarcinogenic target risk levels. The average and maximum
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TABLE 6-6
QUANTITATIVE RISK SUMMARY
OPERABLE UNIT 4 RECORD OF DECISION
LORINQ AIR FORCE BASE
•BIT*
AVERAGE
MAXIMUM
Rl»k
hutex
Ifttk
IntUx
LF-1 BEDROCK GROUNDWATER
LF-1 OVERBURDEN GROUNDWATER
LF-2 SHALLOW BEDROCK GROUNDWATER « 200' bgs)
LF-2 DEEP BEDROCK GROUNDWATER O200' bgs)
LF-2 OVERBURDEN GROUNDWATER: OUTSIDE THE LANDFILL
LF-2 OVERBURDEN GROUNDWATER: INSIDE THE LANDFILL
LF-3/CAP BEDROCK GROUNDWATER
LF-3/CAP OVERBURDEN GROUNDWATER: OUTSIDE THE LANDFILL
LF-3/CAP OVERBURDEN GROUNDWATER: INSIDE THE LANDFILL
CPDA BEDROCK GROUNDWATER
CPDA OVERBURDEN GROUNDWATER
4E-05
7E-07
1E-04
6E-05
6E-06
9E-06
8E-OS
0.02
0.006
1E-04
1E-06
0.1
0.4
1E-05
2E-05
IE 06
1E-06
0.4
0.01
2E-06
3E-08
O.08
0.009
"=v i *\rv:>:
0.1
0.7
" %%%^5 Vjt
0.7
0.02
NOTES:
Sh.d.d v*tu» «xo.«d uppu «nd of USEPA Urgal risk rang* (10-6 to 10-4) or .n HI of 1.0.
Total riiks include ingcstion. deimal. and inhalation •xpoBuraa.
bga •• below ground aurface
OU4SUM.XLS
4/26/98
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SECTION 6
exposure risk estimates for bedrock groundwater exceed the MEDEP cancer risk
guidance value. The maximum exposure risk estimate for bedrock groundwater also
exceeds USEPA target risk levels. Remedial alternatives for both overburden and
bedrock groundwater were evaluated in the FS due to elevated risks.
Actual or threatened releases of hazardous substances to groundwater from LF-2 and
LF-3/CAP, if not addressed by implementing the response action selected in this
ROD in conjunction with the response action selected in the OU 2 ROD, may
present an imminent and substantial endangerment to public health. The objective
of the selected remedial action is to implement institutional controls and conduct
downgradient groundwater monitoring, in conjunction with the low permeability cover
systems being installed as source control under OU 2. Through this action, exposures
to the contaminants in groundwater at LF-2 and LF-3/CAP will be significantly
reduced.
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SECTION 7
7.0 DEVELOPMENT AND SCREENING OF ALTERNATIVES
Three alternatives for LF-2 and LF-3/CAP were developed and screened in the
OU 4 FS (ABB-ES, 1996b). This section describes the response objectives and the
development and screening of alternatives.
The USAF has determined that NFA under CERCLA is necessary for groundwater
associated with LF-1 and the CPDA, and therefore, no remedial alternatives were
developed for these sites.
7.1 STATUTORY REQUIREMENTS/RESPONSE OBJECTIVES
Under its legal authorities, the USAFs primary responsibility at NPL sites is to
undertake remedial actions that are protective of human health and the environment.
In addition, Section 121 of CERCLA establishes several other statutory requirement.*
and preferences, including: a requirement that the USAFs remedial action, when
complete, must comply with all federal and more stringent state environmental
standards, requirements, criteria or limitations, unless a waiver is granted; a
requirement that the USAF select a remedial action that is cost-effective and that
utilizes permanent solutions and alternative treatment technologies or resource
recovery technologies to the maximum extent practicable; and a preference for
remedies in which treatment that permanently and significantly reduces the volume.
toxiciry or mobility of the hazardous substances is a principal element over remedies
not involving such treatment. Response alternatives were developed to be consistent
with these Congressional mandates.
Based on preliminary information relating to types of contaminants, environmental
media of concern, and potential exposure pathways, remedial action objectives were
developed to aid in the development and screening of alternatives. These remedial
action objectives were developed to mitigate existing and future potential threats to
public health and the environment. These response objectives for groundwater at
LF-2 and LF-3/CAP are:
• to prevent human exposure to contaminated groundwater; and
• to protect downgradient groundwater from contamination.
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SECTION 7
12 TECHNOLOGY AND ALTERNATIVE DEVELOPMENT AND SCREENING
CERCLA and the NCP have set forth the process by which remedial actions are
evaluated and selected. In accordance with these requirements, a range of
alternatives were developed for LF-2 and LF-3/CAP.
With respect to groundwater response action, the FS developed a range of
alternatives considering the CERCLA statutory preference for a treatment that
reduces the toxicity, mobility, or volume of the hazardous substances. This range
included an alternative that removes or destroys hazardous substances to the
maximum extent feasible, eliminating or mmimmng to the degree possible the need
for long-term management. This range also included alternatives that treat the
principal threats posed by the site but vary in the degree of treatment employed and
the quantities and characteristics of the treatment residuals and untreated waste that
must be managed; alternative(s) that involve little or no treatment but provide
protection through engineering or institutional controls; and a no action alternative.
Of the five groundwater remedial alternatives screened in Section 6 of the FS, three
were retained for detailed analysis. Tables 6-1 and 6-3 in the FS identify the three
alternatives that were retained through the screening process, as well as those that
were eliminated from further consideration.
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SECTION 8
8.0 DESCRIPTION OF ALTERNATIVES
This section provides a narrative summary of each alternative evaluated in the FS.
The alternatives developed for LF-2 include No Action and Minimal Action. The
alternatives developed for LF-3/CAP include No Action, Minimal Action, and
Groundwater Collection/Treatment/Discharge. A detailed assessment of each
alternative can be found in Section 7.0 of the OU 4 FS (ABB-ES, 1996b).
The landfill cover systems at LF-2 and LF-3 under OU 2 are expected to result in
mitigation of groundwater contamination by isolating a large volume of the waste
from groundwater contact. All alternatives presented are evaluated, with
consideration given to the effects of the cover systems on contaminant concentrations.
8.1 NO ACTION
The No Action alternative was evaluated for both LF-2 and LF-3/CAP (alternatives
LF2-1 and LF3-1 in the FS), as required by the NCP, to provide a baseline against
which other alternatives could be compared during detailed analysis. This No Action
alternative differs from the "traditional" No Action alternative in that beneficial
impacts on groundwater quality are expected from remediation being done in
accordance with OU 2. Therefore, the No Action alternative does not assume that
current conditions, as described in the OU 4 RI Report, would remain even if this
alternative were selected.
Implementation of this alternative would not limit exposure of contaminated
groundwater to existing and future groundwater users outside of the area of landfilled
wastes at LF-2 and LF-3 in the short term. Future residential exposure to
groundwater would remain possible for both new users and existing users. There are
no costs associated with this alternative.
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8.2 MINIMAL ACTION
The Minimal Action alternative was also evaluated for both LF-2 and LF-3/CAP
(alternatives LF2-2 and LF-3-2 in the FS). The components of this alternative, in
addition to the OU 2 actions, are as follows:
• institutional controls
• groundwater monitoring
• five-year site reviews
• contingency action, if necessary (see Subsection 10.2)
This alternative would include institutional controls to protect against human
exposure to contaminated groundwater. Monitoring wells downgradient of LF-2 and
LF-3 would be used to monitor contaminant levels downgradient of the landfill.
These monitoring locations would be used to verify and define the zone of
attainment for action levels, as well as serve as compliance points between existing
groundwater users and the landfills.
Five-year reviews would evaluate the monitoring system, including the frequency of
monitoring, the zone of attainment, and the downgradient distribution of
contaminants. If landfill-related contaminants are detected at the compliance point
at concentrations above the action levels, a contingency action will be implemented.
The contingency action is discussed in Subsection 10.2.
Implementation of this alternative would limit exposure of existing and future
groundwater users to contaminated groundwater outside of the area of landfilled
wastes at LF-2 and LF-3.
Estimated Time of Operation: 30 Years
Estimated Capital Cost: $87,000
Estimated Operation and Maintenance (O&M) Costs (net present worth):
$810,000
Estimated Total Cost (net present worth): $897,000
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SECTION 8
8.3 GROUNDWATER COLLECTION/TREATMENT/DlSCHARGE
The Groundwater Collection/Treatment/Discharge alternative was also evaluated
for LF-3 (alternative LF3-4 in the FS). This alternative consists of components from
the Minimal Action alternative, along with a groundwater collection and treatment
system designed to recover contaminated groundwater from the overburden and
shallow bedrock aquifers downgradient of LF-3. Key components of this alternative
include:
• pre-design hydrogeologic studies
• groundwater extraction system construction
• groundwater treatment facility construction and operation
• treated groundwater discharge
• institutional controls
• groundwater monitoring
• five-year site reviews
Prior to design of this alternative, hydrogeologic studies are recommended to
optimize the design of the groundwater extraction system in controlling contaminant
migration from LF-3.
Because of the existence of a groundwater divide beneath LF-3, two extraction wells
with variable pumping rates of up to 25 gallons per minute (gpm) would be necessary
to prevent off-site migration of contaminated groundwater. One well would be
placed at the northwestern end of LF-3, the other at the southeastern end of the
landfill.
Extracted groundwater would be pumped to a centrally-located groundwater
treatment facility. The following treatment train was selected for this alternative,
based on an evaluation of available treatment technologies: chemical oxidation/
precipitation, filtration, air stripping, and carbon adsorption.
Discharge of the treated groundwater would be to the LAFB wastewater treatment
plant (WWTP) via a trenched forcemain.
Implementation of this alternative would limit exposure of contaminated groundwater
to existing and future groundwater users outside of the area of landfilled wastes at
LF-3. It would provide added protection by preventing the migration of groundwater
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SECTION 8
contaminants from beneath the landfill until the beneficial effects of the cover system
on groundwater quality are realized.
Estimated Time of Operation: 5 to 30 Years
Estimated Capital Cost: $2,257,000
Estimated O&M Costs (net present worth):
Range from $1,761,000 to $3,688,000
Estimated Total Cost (net present worth):
Range from $4,018,000 to $5,945,000
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SECTION 9
9.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES
Section 121(b)(l) of CERCLA presents several factors that, at a minimum, the
USAF is required to consider in its assessment of alternatives. Building upon these
specific statutory mandates, the NCP articulates nine evaluation criteria to be used
in assessing the individual remedial alternatives.
9.1 EVALUATION CRITERIA USED FOR DETAILED ANALYSIS
A detailed analysis was performed on the alternatives using the nine evaluation
criteria in order to select an interim site remedy. Section 92 contains a summary of
the comparison of each alternative's strengths and weaknesses with respect to the
nine evaluation criteria. These criteria are summarized in Subsections 9.1.1 through
9.1.3.
9.1.1 Threshold Criteria
The two threshold criteria described below must be met in order for the alternatives
to be eligible for selection in accordance with the NCP.
• Overall protection of human health and the environment addresses
whether or not a remedy provides adequate protection and describes
how risks posed through each pathway are eliminated, reduced, or
controlled through treatment, engineering controls, or institutional
controls.
• Compliance with applicable or relevant and appropriate requirements
(ARARs) addresses whether or not a remedy will meet all of the
ARARs of other Federal and state environmental laws and/or provide
grounds for invoking a waiver.
9.1.2 Primary Balancing Criteria
The following five criteria are utilized to compare and evaluate the elements of one
alternative to another that meet the threshold criteria.
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SECTION 9
• Long-term effectiveness and permanence addresses the criteria that are
utilized to assess alternatives for the long-term effectiveness and
permanence they afford, along with the degree of certainty that they
will prove successful.
• Reduction of toxicity, mobility, or volume through treatment addresses
the degree to which alternatives employ recycling or treatment that
reduces toxicity, mobility, or volume, including how treatment is used
to address the principal threats posed by the site.
• Short-term effectiveness addresses the period of time needed to
achieve protection and any adverse impacts on human health and the
environment that may be posed during the construction and
implementation period, until cleanup goals are achieved.
• Implementability addresses the technical and administrative feasibility
of a remedy, including the availability of materials and services needed
to implement a particular option.
• Cost includes estimated capital costs (indirect and direct) and annual
O&M costs, as well as present-worth costs.
9.13 Modifying Criteria
The modifying criteria are used on the final evaluation of remedial alternatives
generally after the USAF has received public comment on the RI/FS and Proposed
Plan.
• State acceptance addresses the state's position and key concerns
related to the preferred alternative and other alternatives, and the
state's comments on ARARs and to be considered (TBC) criteria or
the proposed use of waivers.
• Community acceptance addresses the public's general response to the
alternatives described in the Proposed Plan and RI/FS report.
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SECTION 9
92 SUMMARY OF COMPARATIVE ANALYSIS
During the detailed analysis of each individual alternative, a comparative analysis was
conducted, focusing on the relative performance of each alternative against the nine
criteria. The complete comparative analysis is presented in Section 7.0 of the OU 4
FS (ABB-ES, 1996b). The following subsections present the nine criteria and a brief
narrative summary of the alternatives and their strengths and weaknesses according
to the detailed and comparative analysis. A tabular assessment of each alternative
according to the criteria can be found in Table 9-1.
92.1 Overall Protection of Human Health and the Environment
The OU 2 cover system is expected to result in eventual attainment of remediation
goals at both LF-2 and LF-3. An increased level of protection to human health will
be provided in the interim by the Minimal Action alternative through the
implementation of institutional controls. The Groundwater Collection/Treatment/
Discharge alternative would further increase protection by preventing migration of
groundwater contaminants from beneath the landfill until the beneficial effects of the
cover system on groundwater quality are realized.
922 Compliance with Applicable or Relevant and Appropriate Requirements
The No Action alternative would not trigger action- or location-specific ARARs, and
there would be eventual attainment of Maximum Contaminant Levels (MCLs) due
to the effects of the cover system. The Minimal Action alternative will not trigger
location- or action-specific ARARs. Chemical-specific ARARs will be met by the
eventual attainment of MCLs. The Groundwater Collection/Treatment/Discharge
alternative would meet all ARARs during construction and operation, assuming
modifications are made to the WWTP discharge permits.
923 Long-term Effectiveness and Permanence
Because the cover systems currently being constructed at LF-2 and LF-3 are expected
to result in improved groundwater quality, all three alternatives would provide long-
term effectiveness. Permanence of the alternatives is dependent upon proper
maintenance and effectiveness of the cover system.
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TABLE 9-1
COMPARATIVE SUMMARY OF REMEDIAL ALTERNATIVES
OPERABLE UNIT 4 RECORD OF DECISION
LORING AIR FORCE BASE
ALTERNATIVE
LF2-1/
LF3-1
No Action
LF2-2/
LF3-2
Minimal
Action
LF3-4
Groundwater
Collection/
Treatment/
Discharge
OVuUUL PNOn-CTIOM
OU 2 cover system
expected to result in
eventual attainment
of action levels.
Human health may
not be sufficiently
protected during
interim.
OU 2 cover system
expected to result in
eventual attainment
of action levels.
Human health
protected during
interim by institutional
controls.
OU 2 cover system
expected to result in
eventual attainment
of action levels.
Human health
protected during
interim by
groundwater
extraction and
institutional controls.
COMPLIANCE WITH
ARARS
Action- and location-
specific ARARs not
triggered. Eventual
attainment of MCLs.
.
Action- and location-
specific ARARs not
triggered. Eventual
attainment of MCLs.
Meats ARARs during
construction.
Assuming permit
modification to
WWTP. meets
ARARs during
operation.
LONG-TERM
EFFECTIVENESS
Assuming proper
cover system
maintenance, this
alternative provides
long-term
effectiveness and
permanence.
Assuming proper
cover system
maintenance, this
alternative provides
long-term
effectiveness and
permanence.
Assuming proper
cover system
maintenance, this
alternative provides
long-term
effectiveness and
permanence.
REDUCTION OF MOBILITY.
Trt tfWI 1 V AMT^ VfHIMBC
i uwvi IT, nnv v umiivc
No reductions through
treetment, but
mobilizing influences
would be mitigated by
cover system.
No reductions through
treatment, but
mobilizing influences
would be mitigated by
cover system.
Contaminated
groundwater treated
during treatment facility
operation. Mobilization
influences would be
mitigated by cover
system.
SHORT-TERM
EFFECTIVENESS
Not effective
during short- term.
Domestic users of
downgradient
groundwater
potentially
exposed to
contaminants.
Effective during
short term.
Domestic users of
downgradient
groundwater
protected by
institutional
controls.
Effective during
short term.
Domestic users of
downgradient
groundwater
protected by
institutional
controls and
groundwater
extraction.
MtPLEMENTAMUTY
Easily
implementable.
Activities
implemented
under OU 2
closure plan.
Easily
implementable.
Institutional
controls are
assumed to be
implementable on
and off LAFB
property.
Groundwater
extraction and
treatment
implementable.
Discharge to
WWTP expected
to meet regulatory
approval.
COST
$0
$897,000
Variable costs
depending on
length of
operation.
5 Years:
$4,018.000
10 Years:
$4,696,000
20 Years:
$5,524,000
30 Years:
$5,945,000
Notes:
(1) Total Present Worth
21 .TSO/4
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SECTION 9
92A Reduction of Mobility, Toricity, or Volume through Treatment
Since the No Action alternative and the Minimal Action alternative do not
incorporate any treatment system, there would be no reduction due to treatment.
However, the cover system may reduce infiltration and leachate generation. The
Groundwater Collection/Treatment/Discharge alternative would also use the cover
system to mitigate the mobilizing influences, but would provide further protection by
using groundwater collection and treatment to reduce contaminant concentrations to
acceptable levels.
92.5 Short-term Effectiveness
The No Action alternative would provide protection only to potential receptors
engaged in activities in the immediate vicinity of the landfills. The Minimal Action
alternative would provide expanded protection with aggressive and widespread use
of institutional controls and environmental monitoring, while providing contingency
plans in the event that drinking water supplies are affected by contaminated
groundwater. The Groundwater Collection/Treatment/Discharge alternative would
provide a higher level of short-term protection for potential human receptors by
intercepting currently contaminated water that would otherwise continue to affect the
aquifer downgradient of LJF-3.
92.6 Implementability
The No Action alternative does not include remedial actions. Installation of
monitoring wells and well head treatment systems for Minimal Action involves easily
implementable technologies. Implementation of institutional controls would require
coordination with local governments. The technologies available for the construction
of a groundwater extraction and treatment system are more complex and would
require significantly more time to construct.
92.1 Cost
The cost criterion includes both the capital costs of implementing an alternative and
the O&M costs. The No Action alternative has no associated costs. The Minimal
Action alternative has an estimated cost of $897,000 for each landfill, including
installation and monitoring costs. The costs associated with the Groundwater
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SECTION 9
Collection/Treatment/Discharge alternative range from $4,018,000 to $5,945,000
depending on the length of operation of the treatment system.
9.2.8 State Acceptance
The MEDEP, as a party of the FFA, has provided comments on the FS and
Proposed Plan, and has documented its concurrence with the remedial action. As
stated in Section 13 of this ROD. A copy of the MEDEP's letter of concurrence is
presented in Appendix C of this ROD.
92.9 Community Acceptance
The Proposed Plan presents the preferred alternative for LF-2 and LF-3/CAP,
Minimal Action, and the preferred alternative for LF-1 and the CPDA, NFA. From
May 17, 1996 through June 15, 1996, the USAF held a public comment period to
accept public input. A public meeting was held on June 11, 1996 to discuss the
Proposed Plan and to accept any oral comments.
Community acceptance of the Proposed Plan was evaluated based on comments
received at the public meeting and during the public comment period. This is
documented in the transcript of the Public Meeting in Appendix A, and in the
Responsiveness Summary in Appendix B of this ROD.
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SECTION 10
10.0 THE SELECTED REMEDY
The selected remedy for groundwater associated with LF-2 and LF-3/CAP is
Minimal Action (Alternatives LF-2-2 and LF3-2 of the FS). In addition to the source
control remedy outlined in the OU 2 ROD (ABB-ES, 1994b), Minimal Action for
LF-2 and LF-3/CAP will include institutional controls, downgradient groundwater
monitoring, and a contingency action, if necessary, to protect against human exposure
to contaminated groundwater The remedial action is a final remedy for the
groundwater associated with LF-2 and LF-3/CAP.
10.1 ACTION LEVELS
In accordance with USEPA Risk Assessment Guidance for Superfund and the NCP,
the USAF has established, with concurrence of the regulatory agencies, site-specific
action levels that will be protective of human health and the environment. Action
levels have been established for LF-2 bedrock groundwater and LF-3/CAP bedrock
and overburden groundwater, based on the Chemical-specific ARARs (i.e., Drinking
Water MCLs and Maximum Contaminant Level Goals (MCLGs) presented in
Table 11-1 of this ROD, State MEGs, and Risk Assessment (i.e., 1x10* excess cancer
risk level and hazard quotient equals one per compound). If a value described by
any of the above methods was not capable of being detected with sufficient precision
and value, then the practical quantitation limit or background value was used as
appropriate for the groundwater action level. Compounds for which action levels
have been established are listed in Tables 10-1 and 10-2 for LF-2 and LF-3/CAP,
respectively.
Cumulative carcinogenic and noncarcinogenic risk posed by ingestion of groundwater
and inhalation of VOCs from domestic water usage has been calculated for the
contaminants of concern using the action level concentrations. Table 10-3
summarizes the individual and cumulative carcinogenic and noncarcinogenic risks.
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TABLE 10-1
LF-2 BEDROCK GROUNDWATER'"
ACTION LEVELS
OPERABLE UNIT 4 RECORD OF DECISION
LORINQ AIR FORCE BASE
CHEMICAL OF CONCERN
Bta(2-ethylhexyt)prrthalate
Tetrachloroethene
Vinyl Chloride
Cadmium
Iron
Lead
Zinc
MAXIMUM
DETECTED
CONCENTRATION
22
4
1.41
32.6
33,000
495
13,000
PRACTICAL
QUANTTTATION
LIMIT111
10
0.5
0.15
2
25
5
25
BACKGROUND
CONCENTRATION01
_
-
-
0.3
8,330
5.7
59.2
MCL*
6
5
2
5
300"
15W
5,000W
MEG1*
25
3
0.15
5
-
20
-
RISK-BASED
CONCENTRATION118
4.7
0.71
0.019
14
8,400
80
8,400
ACTION
LEVELS1*
10
3
0.15
5
8,400
80
8,400
RATIONALE
POL
MEG
MEG
MCL
Risk-Based
Risk-Based
Risk-Based
s
Source*:
(1)
<2)
(3)
(4)
(5)
(6)
Note*:
PACE, Inc., New England-ME Laboratory, Westbrook, Maine
January 1995 data from OU 12 bedrock wells sampled using conventional sampling procedures
Drinking Water Regulations and Health Advisories, U.S. Environmental Protection Agency, Office of Water, May 1995
The source of these MEGs Is the State of Maine Department of Human Services October 23, 1992 Letter Regarding Revised Maximum Exposure Guidelines.
Calculated at a carcinogenic risk level of 10* or an HI of 1. Lead concentrations would not result in exceedance of USEPA Guidance Blood Lead Level of
10 mterograms per (Her (calculated using Integrated Exposure Uptake Btoklnette Model)
Developed by comparison of maximum detected concentration to POL, background concentration, MCL, MEG, and risk-based concentration.
(a) Includes shallow bedrock (<200 feet bgs) and deep bedrock (>200 feet bgs) groundwater
(b) Secondary Drinking Water Standard, suggested level, not an ARAR
(c) Suggested action (eve) at tap for water systems (SDWA; 40 CFR 141.80). not an MCL or ARAR.
Units mlcrograms per War
MEG Maximum Exposure Guideline
MCL Maximum Contaminant Level
POL Practical Quantttatton UmH
No value
.TBO/1
8741-1
-------
TABLE 10-2
LF-3 BEDROCK AND OVERBURDEN GROUNDWATER
ACTION LEVELS
OPERABLE UNIT 4 RECORD OF DECISION
LORING AIR FORCE BASE
CHEMICAL OF
CONCERN
BEDROCK
Vinyl Chloride
Iron
Manganese
Overburden
1 ,4-Dichlorobenzene
4-Methylphenol
Benzene
Tetrachloroethene
Trichloroethene
Vinyl Chloride
Iron
Manganese
MAXIMUM
DETECTED
CONCENTRATION
2.46
22,700
2,780
42
2,000
11
4
66
0.84
23,200
2,460
PRACTICAL
QUANTTTATION
UMrt'1'
0.15
25
5
0.5
10
0.5
0.5
0.5
0.15
25
5
BACKGROUND
CONCENTRATION121
-
8,333
94
-
-
-
-
-
-
399
112
MCLl3i
2
300*"
50W
75
-
5
5
5
2
300W
50W
MEG'*
0.15
•
200
27
-
5
3
5
0.15
-
200
RISK-BASED
CONCENTRATION1111
0.019
8,400
1,300
1.5
140
1.3
0.71
3.4
0.019
8,400
1,300
ACTION
LEVELS'"
0.15
8,400
1,300
27
140
5
3
5
0.15
8,400
1,300
RATIONALE
MEG
Risk-Based
Risk-Based
MEG
Risk-Based
MCL
MEG
MCL
MEG
Risk-Based
Risk-Based
s
Sources:
(D
(2)
(3)
(4)
(5)
(6)
Notes:
(a)
Units
MEG
MCL
POL
PACE, Inc., New England-ME Laboratory, Westbrook, Maine
Bedrock - January 1995 data from OU 12 bedrock wells sampled using conventional sampling procedures. Overburden - July 1995 data from OU 12 overburden wells
sampled using low-flow sampling procedures.
Drinking Water Regulations and Hearth Advisories, U.S. Environmental Protection Agency, Office of Water, May 1995
The source of these MEGs la the State of Maine Department of Human Services October 23, 1992 Letter Regarding Revised Maximum Exposure Guidelines.
Calculated at a carcinogenic risk level of 10* or an HI of 1.
Developed by comparison of maximum detected concentration to POL, background concentration, MCL, MEG, and risk-based concentration.
Secondary Drinking Water Standard, suggested level, not an ARAR.
mlcrograms per liter (vg/L)
Maximum Exposure Guideline
Maximum Contaminant Level
Practical Quantitatlon Umlt
No value
W0039621.T80/2
8741-16
-------
TABLE 10-3
GROUNDWATER ACTION LEVELS AND RISK SUMMARY
OPERABLE UNIT 4 RECORD OF DECISION
LORING AIR FORCE BASE
LF-2 Bedrock Groundwater
CARCINOGENIC CHEMICAL
OF CONCERN
bis(2-ethylhexyl)phthaJate
Tetracholorethene
Vinvl Chloride
SUMMARY CANCER RISK
ACTION LEVEL
OKS/U
10
3
0.15
BASIS
PQL
MEG
MEG
LEVEL OF RISK
2.1X10"6
4.2X1 0"6
7.7x1 0"6
tXlO41
NONCARCINOQENIC
CHEMICAL OF CONCERN
bis(2-ethy1hexyl)phthalate
Tetrachloroethene
Cadmium
Iron
Lead
Zinc
SUMMARY HAZARD INDEX
ACTION LEVEL
10
3
5
8,400
80
8,400
BASIS
PQL
MEG
MCL
Risk-Based
Risk-Based
Risk-Based
TARGET ENDPOINT OF
TOXICITY
Uver
Uver
Blood
Uver
Central Nervous System,
Blood
Respiratory System*
HAZARD
QUOTIENT
0.018
0.02
0.36
1.0
1.0
2
LF-3 Bedrock Groundwater
CARCINOGENIC CHEMICAL
OF CONCERN
Vinyl Chloride
ACTION LEVEL
foo/14
0.15
BASIS
MEG
LEVEL OF RISK
7.7X1 0*
SUMMARY CANCER RISK : .:.;-."" "•'•'•"'v5"-'.. •'.•-•• .•••"•-•«lff*
CHEMICAL OF CONCERN
Iron
Manganese
Summary Hazard Index
ACTION LEVEL
uxa/U
8,400
1,300
BASIS
Risk-Based
Risk-Based
TttVIWTV
Liver
Central Nervous System
HAZARD
QUOTIENT
1.0
0.99
2
W0039621.T80/5
10-4
-------
TABLE 10-3
GROUNDWATER ACTION LEVELS AND RISK SUMMARY
OPERABLE UNIT 4 RECORD OF DECISION
LORING AIR FORCE BASE
LF-3 Overburden Groundwater
CARCINOGENIC CHEMICAL ACTION LEVEL
OF CONCERN fr/G/L)
1,4-Dichlorobenzene 27
Benzene 5
Tetrachoroethene 3
Trichloroethene 5
Vinyl Choloride 0.15
SUMMARY CANCER RISK
BASIS
MEG
MCL
MEG
MCL
MEG
LEVEL OF RISK
1.7X10'5
3.9x1 0"6
4.2x1 0"6
1.5X10"6
7.7x1 ff6
3x10* :-:;j;::' •'•;.;:- ••;:": • •••
NONCARCINOGENIC ACTION LEVEL
CHEMICAL OF CONCERN 0/Q/L)
Benzene 5
Tetrachloroethene 3
Trichloroethene 5
4-Methylphenol 140
Iron 8,400
Manganese 1,300
SUMMARY HAZARD INDEX
Notes:
(a) based on zinc compounds
fjg/L micrograms per liter
MEG Maximum Exposure Guideline
MCL Maximum Contaminant Level
POL Practical Quantitation Limit
BASIS
MCL
MEG
MCL
Risk-Based
Risk-Based
Risk-Based
TARGET ENDPOINT OF
TOXICITY
Blood
Liver
Liver, Respiratory System,
Heart, Central Nervous
System, Kidneys
Central Nervous System,
Respiratory System
Liver
Central Nervous System
HAZARD
QUOTIENT
1.1
0.02
0.053
1.0
1.0
0.99
4
10-5
W0039621.T80/6
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SECTION 10
The action levels are consistent with ARARs criteria for groundwater and attain
USEPA's risk management goal for remedial actions. The determination of the
effectiveness of the remedy cannot be made until residual levels are known. If
concentrations above action levels are detected at the compliance point, a risk
assessment will be performed on the residual groundwater contamination to
determine whether the remedial action is protective. This assessment and
contingency action are discussed in Subsection 10.2.
10.2 DESCRIPTION OF REMEDIAL COMPONENTS
The following paragraphs describe the remedial alternative developed by the USAF
for groundwater associated with LF-2 and LF-3/CAP: Minimal Action. In addition
to the OU 2 low permeability cover systems, 30-year landfill post-closure monitoring,
and deed restrictions, implementation of the selected alternative will include the
following activities:
• institutional controls;
• groundwater monitoring;
• five year site reviews; and
• contingency action, if necessary.
The components are described in the following paragraphs.
Institutional Controls. The ROD for OU 2 (ABB-ES, 1994b) specifies the use of
property deed restrictions on the land in the vicinity of the landfills (i.e., limits of the
cover systems) to limit subsurface development (excavation or drilling), use of the
property, and excessive vehicular traffic (including off-road vehicles and dirt bikes).
Consequently, installation of drinking water supply wells within the landfills will not
be possible. The OU 2 deed restrictions are intended to protect human health and
the environment from exposure to landfilled waste and to restrict activities that could
compromise the integrity of the final cover system.
In addition to the restrictions for OU 2, institutional controls will be established for
OU 4 to restrict the use of groundwater. The limits of institutional controls are
presented on Figure 10-1. These limits would restrict groundwater use from the
perimeter of the landfills to the adjacent property lines or a minimum of 500 feet
Installation Restoration Program
W0039621.080 8741-16
10-6
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KETCH POND
LEGEND
_ COMPLIANCE BOUNDARY
BASE BOUNDARY
INSTITUTIONAL CONTROL BOUNDARY
FIGURE 10-1
COMPLIANCE AND
INSTITUTIONAL
CONTROL BOUNDARIES
1600 FEET
LOHNG AIR FORCE BASE
LIMESTONE. MAINE
SCALE: 1"=800'
10-7
-------
SECTION 10
where possible, and would be inclusive of downgradient monitoring wells.
Restrictions on property transferred from the USAF and located in the vicinity and
downgradient of the landfills would prohibit installation of drinking water wells and
prohibit the use of underlying and downgradient groundwater.
Groundwater Monitoring. Groundwater monitoring at wells located upgradient,
within, and immediately downgradient of the landfill, is incorporated into the OU 2
ROD for the 30-year post-closure monitoring period. Monitoring wells will be used
further downgradient as part of the Minimal Action alternative, to monitor
contaminant levels downgradient of the landfill. These monitoring locations will be
at the compliance boundary, shown on Figure 10-1, and will serve as compliance
points between existing groundwater users and the landfills. One residential well
(Hopkins Residence) downgradient of LF-2 on Nebraska Road adjacent to the base
property line will also be monitored. If concentrations of contaminants above action
levels are detected at a compliance point, a contingency action will be implemented.
The downgradient zone beyond the compliance boundary will be covered by
groundwater use restrictions as a minimum requirement to protect human health.
OU 2 groundwater monitoring performed in conjunction with OU 4 groundwater
monitoring will be used not only to assess contaminant migration and geochemical
attenuation, but also to measure the performance of the cover systems in reducing
leachate generation and associated groundwater contamination.
The Post-Closure Plan for OUs 2 and 4 (ABB-ES, 1996d) proposes monitoring wells
for OU 2 post-closure monitoring based on knowledge of local hydrogeologic
conditions. At LF-2, the USAF has proposed a new upgradient bedrock and
overburden pair of wells southeast of, and adjacent to, the perimeter road; existing
downgradient bedrock wells JMW-0802 (Zone B) and JMW-0801 (Zone B); existing
downgradient overburden wells, JMW-0805 and JMW-0806; a new downgradient
overburden well to be installed next to JMW-0801; and existing overburden well
JMW-0882 located within the LF-2 waste boundaries. At LF-3/CAP, the USAF has
proposed existing upgradient bedrock wells JMW-0941 on the southwest, and
JMW-0960 on the northeast; existing upgradient overburden well JMW-0961; a new
upgradient overburden well to be installed next to JMW-0941; new overburden and
bedrock well pair is proposed for the south downgradient wells; new overburden well
and retrofitting bedrock well RFW-39 with a screen are proposed for north
downgradient wells; and overburden well JMW-0980 located within the LF-3 waste
boundaries.
installation Restoration Program
W0039621.080 8741-16
10-8
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SECTION 10
The USAF proposes to use two bedrock and overburden well pairs further
downgradient of LF-2 and LF-3/CAP for OU 4 monitoring to augment the proposed
OU 2 groundwater monitoring plan. New bedrock and overburden wells for LF-2
will be located approximately 400 feet northwest (downgradient) of LF-2. The
downgradient well pair for LF-3/CAP, JMW-0991 and JMW-0992, will be located
approximately 400 feet southeast (downgradient) of LF-3/CAP.
The monitoring locations selected will be at the compliance boundary and allow for
sufficient time to modify the minimal action remedy, should downgradient impacts
above the action levels be identified in the monitoring program. Selected monitoring
well locations as currently proposed are shown on Figure 10-2. The final selection
of monitoring well locations will be presented in the Final Post-Closure Plan for OUs
2 and 4.
OU 2 and OU 4 groundwater monitoring will be conducted on the same sampling
and reporting schedule. Details on the monitoring program, including sampling
frequency will be presented in the Post-Closure Plan for OUs 2 and 4. The Hopkins
(formally Gauvin) well downgradient of LF-2 on Nebraska Road adjacent to the base
property line will be sampled and analyzed annually. The analytical program for all
wells will use the same analytical methods and quality control levels presented in the
Post-Closure Plan for OUs 2 and 4 (ABB-ES, 1996d). Contaminants on Table 10-3
will be charted and tracked. Analytical results from downgradient wells will be
analyzed every year using statistical trend analysis to identify statistically significant
increases or decreases over time. Details on the statistical trend test and reporting
requirements can be found in the Post-Closure Plan for OUs 2 and 4 (ABB-ES,
1996d).
Contingency Action. Currently there are no exceedances of the action levels at the
compliance boundary. The Post-Closure Plan for OUs 2 and 4, discussed previously
in Subsection 10.2 of this ROD, will locate monitoring wells for evaluating the
effectiveness of the LF-2 and LF-3 cover system on groundwater migration and for
determining compliance. The Post-Closure Plan will also describe the manner in
which the USAF will monitor these wells. The USAF will notify the USEPA and
MEDEP immediately if concentrations above the action levels set forth in Tables 10-
1 through 10-2 are detected in any compliance wells.
If concentrations above action levels are detected at any of these compliance wells,
the USAF will also sample all potable water supplies downgradient of the landfills
Installation Restoration Program
W0039621.080 8741-16
10-9
-------
SECTION 10
which might be affected by contamination originating from the landfills. In addition,
the USAF will perform a risk assessment on the groundwater for OU 4 to determine
whether the remedial action adopted herein is protective. This risk assessment will
comply with the Loring Air Force Base Risk Assessment Methodology (HAZWRAP,
1994).
If, after review of the risk assessment, the remedial action is determined not to be
protective by the USEPA and MEDEP, the remedial project managers (as defined
in the FFA) shall decide what contingency action will be necessary. The contingency
action will include an evaluation by the USAF of the effectiveness of the LF-2 and
LF-3 cover systems to prevent groundwater migration, and may include either passive
or active remedial options. Passive components may include, but are not limited to,
the hook-up of threatened or affected residences to public water supplies and the
implementation of institutional controls on the affected properties. Active
components may include, but are not limited to, plume control measures, the
construction of a slurry wall, or a groundwater extraction and treatment system. Any
active component which may be implemented shall be presented in a CERCLA
decision document (e.g., ROD Amendment, Explanation of Significant Differences
[ESD], or a new ROD) pursuant to applicable USEPA guidance. If a future active
contingency measure is determined to be appropriate, groundwater ARARs will be
evaluated and designated at the time of the new CERCLA decision document.
The USEPA, MEDEP, or the Air Force have the authority to implement the Dispute
Resolution process for any action conducted within the scope of the Installation
Restoration Program, pursuant to Section 14.2(2) of the Loring Federal Facilities
Agreement (as amended).
Five-year Site Reviews. Results of groundwater monitoring for LF-2 and LF-3/CAP
will be included in an Annual Report to be submitted to the MEDEP as specified
by the Post-Closure Plan for OUs 2 and 4 (ABB-ES, 1996d). In addition to the
Annual Report, the USAF will review the LF-2 and LF-3/CAP monitoring program
at least once every five years in accordance with applicable USEPA guidance. The
five-year site reviews are intended to evaluate whether the response action continues
to protect human health and the environment, assess site conditions, and propose
further actions, if necessary.
Installation Restoration Program
W0039621.080 8741-16
10-10
-------
1600 FEETi
KETCH POND
SCALE: 1" = 800'
L LANDFILL 3
LEGEND
COMPLIANCE BOUNDARY
BASE BOUNDARY
INSTITUTIONAL CONTROL BOUNDARY
INTERPRETED GROUNDWATER
CONTOUR
OVERBURDEN MONITORING WELL LOCATION
BEDROCK MONITORING
WELL LOCATION
NEW MONITORING WELL LOCATION
FIGURE 10-2
INTERPRETED WATER TABLE
CONTOURS AND GROUNDWATER
MONITORING WELLS
_ INTERPRETED DIRECTION OF
"* GROUNDWATER MOVEMENT
LOHNG AIR FORCE BASE
LIMESTONE, MAINE
INTERPRETED GROUNDWATER
DIVIDE
10-11
-------
SECTION 11
11.0 STATUTORY DETERMINATIONS
The remedial action selected for implementation at the OU 4 locations, LF-2 and
LF-3/CAP, is consistent with CERCLA and, to the extent practicable, the NCP.
Implementation of this remedy is intended to be in conjunction with the LF-2 and
LF-3 cover systems constructed under OU 2. The selected remedy is protective of
human health and the environment, attains ARARs, and is cost- effective. The
remedy, applied in combination with the cover systems, uses permanent solutions to
the maximum extent practicable. The selected remedy does not satisfy the statutory
preference for remedies that employ treatment that reduces toxicity, mobility, or
volume as a principal element. However, the selected remedy, in combination with
the landfill cover systems, will most likely reduce toxicity through isolation of the
waste material from infiltrating rainwater, and reduce mobility of contaminants
through the containment features of the cover systems.
ll.l THE SELECTED REMEDY is PROTECTIVE OF HUMAN HEALTH AND THE
ENVIRONMENT
The selected remedy, in conjunction with the landfill cover systems, will meet the
response objectives of preventing human exposure to contaminated groundwater and
protecting downgradient groundwater from contamination. Landfill capping will
prevent a large volume of the pre-cap wastes above the water table from further
leaching and cause a large reduction in the generation of leachate. Groundwater
table conditions under the landfills are not anticipated to change to any great extent,
due to exclusion of recharge areas from capping. Therefore, the net effect of capping
will be a reduction in groundwater contamination beneath and downgradient of LF-2
and LF-3/CAP. Placement of the cover systems is expected to lead to the eventual
attainment of remediation goals at LF-2 and LF-3, through the reduction of
groundwater/waste interaction.
Elimination of human exposure to groundwater within and immediately downgradient
of the landfills is incorporated in OU 2, and will be augmented in the selected
remedy by the use of additional institutional controls, enhanced groundwater
monitoring, and contingency actions, if necessary.
Installation Restoration program
W0039621.080 8741-16
11-1
-------
SECTION 11
11.2 THE SELECTED REMEDY ATTAINS ARARs
The selected remedy will attain ARARs. The ARARs for this remedy and the
manner in which they will be met are summarized in Table 11-1.
11.3 THE SELECTED REMEDIAL ACTION is COST-EFFECTIVE
In the USAFs judgment, the selected remedy is cost-effective (i.e., the remedy
affords overall effectiveness proportional to its costs). In selecting this remedy, once
the USAF identified alternatives that were protective of human health and the
environment and that attain ARARs, the USAF evaluated the overall effectiveness
of each alternative by assessing the relevant three criteria - long term effectiveness
and permanence; reduction in toxicity, mobility, or volume through treatment; and
short-term effectiveness - in combination. The relationship of the overall
effectiveness of this remedial alternative was determined to be proportional to its
costs. The costs of this remedial alternative for each landfill are:
Estimated Capital Cost: $87,000
Estimated O&M Costs (net present worth): $810,000
Estimated Total Cost (net present worth): $897,000
The selection of this alternative represents a reasonable value with regard to the
other alternatives. Compared to the other alternative that provides overall protection
to human health and the environment and complies with ARARs, the selected
remedy is much less expensive. All costs of the landfill cover systems are incurred
under OU 2.
Installation Restoration Program
W0039621.080 8741-16
11-2
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TABLE 11-1
CHEMICAL-SPECIFIC ARARs, CRITERIA. ADVISORIES, AND GUIDANCE
MINIMAL ACTION ALTERNATIVE
OPERABLE UNIT 4 RECORD OF DECISION
LORINQ AIR FORCE BASE
MEDIA
REQUIREMENT
STATUS
REQUIREMENT SYNOPSIS
ACTION TO BE TAKEN
TO ATTAIN ARAR
GROUNDWATER
Federal
Safe Drinking Water
Act (SDWA) -
Maximum
Contaminant Levels
(MCLs) (40 CFR
141.11 - 141.16)
SDWA - Maximum
Contaminant Level
Goals (MCLGs) (40
CFR 141.50-
141.51)
Relevant and MCLs have been promulgated for several
Appropriate common organic and inorganic
contaminants. These levels regulate the
concentration of contaminants in public
drinking water supplies, but may also be
considered relevant and appropriate for
groundwater aquifers used for drinking
water.
Relevant and MCLGs are health-based criteria to be
Appropriate considered for drinking water sources.
MCLGs are available for several organic
and inorganic contaminants. Non-zero
MCLGs are to be used as goals when
MCLs have not been established.
Use of the minimal action
remedy will result in attainment
of MCLs in the groundwater at
the compliance boundary.
Use of the minimal action
remedy will result in attainment
of non-zero MCLGs in the
groundwater at the compliance
boundary.
Note*:
ARAR = Applicable or Relevant and Appropriate Requirement
CFR = Code of Federal Regulations
MCL = Maximum Contaminant Level
MCLG = Maximum Contaminant Level Goal
NCP = National Contingency Plan
OU = Operable Unit
SOWA = Safe Drinking Water Act
W003962I.T80/5
8741-16
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SECTION 11
11.4 THE SELECTED REMEDY UTILIZES PERMANENT SOLUTIONS AND ALTERNATIVE
TREATMENT OR RESOURCE RECOVERY TECHNOLOGIES TO THE MAXIMUM
EXTENT PRACTICABLE
Once the USAF identified those alternatives that attain or, as appropriate, waive
ARARs, and that are protective of human health and the environment, the USAF
identified that alternative which utilizes permanent solutions and alternative
treatment technologies or resource recovery technologies to the maximum extent
practicable. This determination was made by identifying the alternative that provides
the best balance of trade-offs among alternatives, in terms of: 1) long-term
effectiveness and permanence; 2) reduction of toxicity, mobility, or volume through
treatment; 3) short-term effectiveness; 4) implementability; and 5) cost. The
balancing test emphasized long-term effectiveness and permanence and the reduction
of toxicity, mobility or volume through treatment; and considered the preference for
treatment as a principal element, the bias against off-site land disposal of untreated
waste, and community and state acceptance.
The selected remedy, when implemented in conjunction with the OU 2 landfill cover
systems, provides the best balance of trade-offs among the alternatives. The selected
remedy provides long-term protection of human health and the environment because
once cover construction is complete, future migration of contaminants will be
reduced. Landfill capping will exclude a large volume of the pre-cap wastes above
the water table from further leaching, having the potential to cause a large reduction
in the generation rate of leachate. The net effect will be a reduction in groundwater
contamination beneath and downgradient of LF-2 and LF-3. Placement of the cover
systems is expected to lead to the eventual attainment of action levels at LF-2 and
LF-3 due to the reduction of groundwater/waste interaction.
The selected remedy will not reduce mobility, toxicity, or volume through treatment
of source area contaminants. However, the selected remedy, in combination with the
landfill cover systems, will most likely reduce toxicity through isolation of the waste
material from infiltrating rainwater, and reduce mobility of contaminants through the
containment features of the cover systems. Placement of the cover systems is
expected to lead to the eventual attainment of action levels at LF-2 and LF-3/CAP,
due to the reduction of groundwater/waste interaction.
The selected remedy provides expanded protection with use of institutional controls
and environmental monitoring. Adverse effects on workers are not anticipated,
installation Restoration program
W0039621.080 8741-16
11-4
-------
SECTION 11
provided safe working practices are followed. Adverse effects on the community are
not expected as a result of implementing the selected remedy.
Installation of the selected remedy involves easily implementable, reliable, and
available technologies.
The selected remedy is cost-effective in that it provides a reasonable value with
regard to the other alternatives. It provides overall protection to human health and
the environment, complies with ARARs, meets the response objectives, and is the
least expensive.
11.5 THE SELECTED REMEDY DOES NOT SATISFY THE PREFERENCE FOR
TREATMENT WHICH PERMANENTLY AND SIGNIFICANTLY REDUCES THE
TOXICITY, MOBILITY OR VOLUME OF THE HAZARDOUS SUBSTANCES AS A
PRINCIPAL ELEMENT
The selected remedy will not reduce mobility, toxicity, or volume through treatment
of source area contaminants as a principal element. However, the selected remedy.
in combination with the landfill cover systems, will most likely reduce toxicity through
isolation of the waste material from infiltrating rainwater, and reduce mobility of
contaminants through the containment features of the cover systems. Placement of
the cover systems is expected to lead to the eventual attainment of action levels at
LF-2 and LF-3/CAP through the reduction of groundwater/waste interaction.
Installation Restoration Program
W0039621.080 8741-16
11-5
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SECTION 12
12.0 DOCUMENTATION OF NO SIGNIFICANT CHANGES
The USAP presented a Proposed Plan (ABB-ES, 1996c) outlining the proposed
alternative of Minimal Action for groundwater associated with LF-2 and LF-3/CAP,
and NFA for groundwater associated with LF-1, the CAP, and the CPDA. The
Proposed Plan was presented to the public, and public comments have been
considered prior to the selection of the preferred alternative.
No significant changes have been made to the preferred alternative described in the
Proposed Plan.
installation Restoration Program
W0039621.080 8741-16
12-1
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SECTION 13
13.0 STATE ROLE
The MEDEP, as a party of the FFA, has reviewed the various alternatives. The
MEDEP has also reviewed the Remedial Investigation, Risk Assessment and
Feasibility Study to determine if the selected remedy is in compliance with applicable
or relevant and appropriate state environmental laws and regulations.
The MEDEP concurs with the selected remedy for OU 4. A copy of the letter of
concurrence is presented in Appendix C of this ROD.
Installation Restoration Program
W0039621.080 8741-16
13-1
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GLOSSARY OF ACRONYMS AND ABBREVIATIONS
ABB-ES ABB Environmental Services, Inc.
ACC Air Combat Command
AFCEE Air Force Center for Environmental Excellence
ARAR Applicable or Relevant and Appropriate Requirement
BEHP bis(2-ethylhexyl)phthalate
bgs below ground surface
CADA Coal Ash Disposal Area
CAP Coal Ash Pile
CERCLA Comprehensive Environmental Response, Compensation, and
Liability Act
CFR Code of Federal Regulations
COC chemical of concern
CPC chemical of potential concern
CPDA Chapman Pit Disposal Area
CRP Community Relations Plan
DCA dichloroethane
DCE dichloroethene
DDA Drum Disposal Area
DHS Department of Human Services
ESD Explanation of Significant Differences
FFA Federal Facilities Agreement
FS Feasibility Study
gpm gallons per minute
HAZWRAP Hazardous Waste Remedial Actions Program
HI Hazard Index
IEUBK Integrated Exposure Uptake Biokinetic
IRP Installation Restoration Program
LAFB Loring Air Force Base
Law Law Environmental, Inc.
W0039621.080
Installation Restoration Program
8741-16
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GLOSSARY OF ACRONYMS AND ABBREVIATIONS
LF Landfill
LFS low-flow sampling
MCL Maximum Contaminant Level
MCLG Maximum Contaminant Level Goal
MEDEP Maine Department of Environmental Protection
MEG Maximum Exposure Guideline
mg/L milligrams per liter
NCP National Contingency Plan
NFA No Further Action
NPL National Priorities List
O&M operation and maintenance
OU operable unit
PA Preliminary Assessment
PAH polynuclear aromatic hydrocarbons
PCB polychlorinated biphenyl
PCDA Paint Can Disposal Area
PCE tetrachloroethene
PQL Practical Quantitation Limit
RA risk assessment
RAB Restoration Advisory Board
RCRA Resource Conservation and Recovery Act
RI remedial investigation
RME reasonable maximum exposure
ROD Record of Decision
SAC Strategic Air Command
SARA Superfund Amendments and Reauthorization Act
SDWA Safe Drinking Water Act
SI site investigation
SVOC semivolatile organic compound
TBC to be considered
TCE trichloroethene
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GLOSSARY OF ACRONYMS AND ABBREVIATIONS
TPH total petroleum hydrocarbon
USAF U.S. Air Force
USEPA U.S. Environmental Protection Agency
/xg/Dl micrograms per deciliter
Hg/L micrograms per liter
VOC volatile organic compound
WWTP Waste Water Treatment Plant
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REFERENCES
ABB Environmental Services, Inc. (ABB-ES), 1994a. OU 2 Remedial Investigation/
Focused Feasibility Study; Final; Installation Restoration Program; Loring Air
Force Base; prepared for HAZWRAP; Portland, Maine; August 1993, revised
July 1994.
ABB Environmental Services, Inc. (ABB-ES), 1994b. OU 2 Record of Decision; Final
Installation Restoration Program; Loring Air Force Base; prepared for
HAZWRAP; Portland, Maine; November 1994.
ABB Environmental Services, Inc. (ABB-ES), 1995. OU 4 Remedial Investigation
Report; Final; Installation Restoration Program; Loring Air Force Base;
prepared for HAZWRAP; Portland, Maine; November 1995.
ABB Environmental Services, Inc. (ABB-ES), 1996a. Operable Unit 2A (OU 2A)
Record of Decision; Final; Installation Restoration program; Loring Air Force
Base; prepared for HAZWRAP; Portland, Maine; March 1996.
ABB Environmental Services, Inc. (ABB-ES), 1996b. OU 4 Feasibility Study; Final;
Installation Restoration Program; Loring Air Force Base; prepared for
HAZWRAP; Portland, Maine; May 1996.
ABB Environmental Services, Inc. (ABB-ES), 1996c. Proposed Plan, No Further
CERCLA Action and Minimal Action for Operable Unit 4; Installation
Restoration Program; Loring Air Force Base; prepared for HAZWRAP;
Portland, Maine; May 1996.
ABB Environmental Services, Inc. (ABB-ES), 1996d. Post-Closure Plan for OUs 2
and 4; Draft Final; Installation Restoration Program; Loring Air Force Base;
prepared for HAZWRAP; Portland, Maine; May 1996.
Advanced Sciences, Inc. (ASI), 1994. Draft Final RI Report for OU 2A, Loring Air
Force Base; prepared for HAZWRAP; Oak Ridge, Tennessee; December
1994.
Air Force Center for Environmental Excellence (AFCEE), 1995. Remedial Action
Report/Project Closure Report, OU 2, OU 2A, OU 6, OU 7, and Other Sites;
Loring Air Force Base; January 1995.
installation Restoration Program
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REFERENCES
CH2M Hill, 1984. Records Search Report; Installation Restoration Program; Loring
Air Force Base; prepared for HAZWRAP; Limestone, Maine; January 1984.
Federal Facility Agreement (FFA) Under CERCLA Section 120, The Matter of
Loring Air Force Base by U.S. Environmental Protection Agency Region I,
State of Maine, and the U.S. Department of the Air Force, January 30, 1991.
Hazardous Waste Remedial Actions Program (HAZWRAP), 1994. Loring Air Force
Base Risk Assessment Methodology; Final; Environmental Restoration and
Waste Management Programs, Oak Ridge, TN; August, 1994.
Law Environmental, Inc. (Law), 1996. Final RI/ASI Technical Report for Debris
Disposal Areas - Operable Unit 3; Loring Air Force Base; March, 1996.
Loring Air Force Base (LAFB), 1995. "Consensus Statement: Inorganic
Contaminants in Overburden Groundwater"; prepared for Loring Air Force
Base, the U.S. Environmental Protection Agency, Region I, and the Maine
Department of Environmental Protection; August 1995.
Patterson, James W., 1985. Industrial Wastewater Treatment Technology:
Butterworth Publishers; Stoneham, Massachusetts.
Maine Department of Environmental Protection and Department of Human Services
(MEDEP/DHS), 1994. Guidance Manual for Human Health Risk Assessments
at Hazardous Substance Sites; June 1994.
RKG Associates, 1995. "Executive Summary - Loring Redevelopment Plan;
Financial, Marketing and Implementation Strategy"; Prepared for Loring
Development Authority of Maine; Durham, New Hampshire; March 1995.
Tseng, W. P, Chu, H. M., How, S. W., Fong, J. M., Lin, C. S., and Yen, S., 1968.
"Prevalence of Skin Cancer in an Endemic Area of Chronic Arsenicism in
Taiwan"; J. Natl. Cancer Inst. 40: 453-463.
Installation Restoration Program
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REFERENCES
U.S. Environmental Protection Agency (USEPA), 1982. "Letter from Robert M.
Perry, Associate Administrator, Office of General Counsel to Rita Lavelle,
Assistant Administrator for Office of Solid Waste and Emergency Response";
September 1, 1982.
U.S. Environmental Protection Agency (USEPA), 1988a. Guidance for Conducting
Remedial Investigations and Feasibility Studies Under CERCLA; Office of Solid
Waste and Emergency Response; OSWER Directive 9335.01; Washington,
DC; March 1988.
U.S. Environmental Protection Agency (USEPA), 1989a. Risk Assessment Guidance
for Superfund: Human Health Evaluation Manual (Part A); Volume 1; Interim
Final; USEPA 540/1-89/002; Washington, DC; December 1989.
U.S. Environmental Protection Agency (USEPA), 1989b. Exposure Factors
Handbook; Exposure Assessment Group; Office of Health and Environmental
Assessment; USEPA/600/8-89/043.
U.S. Environmental Protection Agency (USEPA), 1989c. Ecological Assessment of
Hazardous Waste Sites: A Field and Laboratory Reference; Environmental
Research Laboratory; U.S. Environmental Protection Agency; Corvallis,
Oregon; EPA 600/3-89/013.
U.S. Environmental Protection Agency (USEPA), 1989d. Supplemental Risk
Assessment Guidance for Superfund Program; USEPA Region I Risk
Assessment Work Group; USEPA 901/5-89-001.
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 seq.; March 8, 1990.
U.S. Environmental Protection Agency (USEPA), 1991a. Risk Assessment Guidance
for Superfund. Volume I: Human Health Evaluation Manual, Part A,
Supplemental Guidance, "Standard Default Exposure Factors," Interim Final;
Office of Solid Waste and Emergency Response 9285.6-03; March 25, 1991.
Installation Restoration Program
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REFERENCES
U.S. Environmental Protection Agency (USEPA), 1991b. Loring RJ Report/Risk
Assessment Approach Meeting between representatives of EPA Region I,
Maine Department of Environmental Protection, U.S. Fish and Wildlife
Service, Loring AFB, HAZWRAP, ABB Environmental Services;
December 6, 1991.
U.S. Environmental Protection Agency (USEPA), 1995b. Health Effects Assessment
Summary Tables (HEAST), Annual FY 1995, EPA 540/R-95/O36.
PB95-921199. USEPA, Office of Solid Waste and Emergency Response. May,
1995.
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APPENDIX A
TRANSCRIPT OF THE PUBLIC MEETING (JUNE 11, 1996)
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STATE OF MAINE AROOSTOOK, ss
OPERABLE UNITS 4, 9 & 11
PUBLIC HEARING
JUNE 11, 1996
CARIBOU CITY COUNCIL CHAMBER
CARIBOU, MAINE
7:26 P.M.
BENNETT LEGAL TRANSCRIPT SERVICES
P. 0. Box 947
Caribou, ME 04736-0947
(207)498-2729
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TABLE OF CONTENTS
1 PETER FORBES
2
3
4 EXHIBITS
5 NONE
6
7
8
9
10
11
12
13
14
15
16
17
18
.19
20
21
22
23
24
25
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1
2
3 June 11, 1996
4
5 PETER FORBES: Good
6 evening. Welcome to the public hearing to receive
7 comments on the proposed plans for Operable Units
8 4 and 9 and 11 at Loring Air Force Base. Today's
9 date is June llth, 1996. My name is Peter
10 Forbes, the Remedial Project Manager for the
n Installation Restoration Program at Loring.
12 Seated with me are Michael Nalipinski, Remedial
13 Project Manager for the U.S. Environmental
14 Protection Agency, and Naji Akladiss, Remedial
15 Project Manager for the Maine Department of
16 Environmental Protection, and they will assist me
17 in receiving your comments
18 This hearing is being held in accordance with
19 the provisions of the Comprehensive Environmental
20 Response Compensation and Liability Act or CERCLA
21 as amended in 1986, also known as Superfund. The
22 ;' act requires federal facilities on the National
23 Priorities List to present clean up proposals to
24 the local community for comment and consideration
25 before the final clean up decisions are made. The
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4
i purpose of this hearing is to receive comments on
2 the Proposed Plans for Operable Units 4 and 9 and
3 11.
4 Mr. Philip Bennett from Aroostook Legal
5 Reporters will serve as the court reporter
6 tonight, preparing a verbatim record of the
7 proceedings. The verbatim record will become a
8 part of the final clean up plan. The court
g reporter will be able to make a complete record
10 only if he is able to hear and understand what you
n say. With that in mind, please follow these
12 ground rules. Speak only after I recognize you
13 and please address your remarks to me. State your
14 name and the organization you represent and
is present your statement. Do not begin speaking
16 until you have reached the microphone and speak
17 slowly and clearly into the microphone. If you
IB have prepared your statement beforehand, you may
19 read it aloud or you may paraphrase it and place
20 it on the table.
21 Are there individuals wishing to make a
22 comment or statement at this time?
23 Ladies and gentlemen, it is 7:30 p.m., June
24 11, 1996 and I declare the public hearing to
25 receive comments on the Proposed Plans for
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5
Operable Units 4 and 9 and 11 at Loring Air Force
2 Base closed. Thank you all for coming.
3
4
5
6
7
8 CERTIFICATION
9
10
n I HEREBY CERTIFY THAT the foregoing is a true and
correct transcript of my stenographic notes taken
13 at the Operable Units 4 & 9, 11 Public Hearing
14 held on June 11, 1996.
15
16
17
19 Philip R. Bennett, Jr.,
20 Court Reporter
21
22
23
24
25 STATE OF MAINE AROOSTOOK, ss.
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APPENDIX B
RESPONSIVENESS SUMMARY
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APPENDIX B
OU 4 RESPONSIVENESS SUMMARY
The Air Force held a 30-day comment period from May 17, 1996 to June 15, 1996,
to provide an opportunity for the public to comment on the Proposed Plan and other
documents developed for Operable Unit (OU 4) at Loring Air Force Base, Maine.
The Proposed Plan is the document that identifies remedial action objectives,
evaluates remedial alternatives, and recommends the alternative that best meets the
evaluation criteria for OU 4.
The Air Force made a recommendation of its preferred alternative for No Further
Action for Landfill (LF) 1 and Chapman Pit Disposal Area, and Minimal Action for
groundwater associated with LF-2 and LF-3/Coal Ash Pile (CAP) in the OU 4
Proposed Plan. The Proposed Plan was issued on May 17, 1996, before the start of
the comment period. All documents on which the preferred alternative is based were
placed in the Administrative Record for review. The Administrative Record is a
collection of the documents considered by the Air Force when choosing the remedial
action for OU 4 groundwater.
The Air Force received no verbal or written comments on the OU 4 Proposed Plan
at a public hearing held on June 11, 1996, or during the 30 day public comment
period.
The Air Force will select the Minimal Action alternative for groundwater associated
with LF-2 and LF-3/CAP, which includes institutional controls, groundwater
monitoring, five-year site reviews, and contingency action if necessary. Institutional
controls will be established to restrict groundwater use, and groundwater monitoring
will be integrated with OU 2 into a comprehensive monitoring program. Five-year
site reviews will be conducted to ensure that the remedial action continues to be
protective of human health and the environment If landfill-related contaminants are
detected at the compliance point at concentrations above the action levels, a
contingency action will be implemented. The contingency action is discussed in
Subsection 10.2 of the OU 4 ROD.
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APPENDIX C
LETTER OF CONCURRENCE
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*r - ^ DEPARTMENT OF ENVIRONMENTAL PROTECTION
ANCU/S S. KING, JR. EDWARD O. SULLIVAN
GOVERNOR COMMISSIONER
September 25, 1996
Mr. Alan K. Olscn
AFBCA/DR
1700 N. Moore Street, Suite 2300
Arlington, VA 22209-2802
Re: Loring Air Force Base Superfund Site, Maine
Dear Mr. Olsen:
The Maine Department of Environmental Protection (MEDEP) has reviewed the Draft
Final Record of Decision (ROD) regarding Operable Unit 4 (OU4) 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 recommendations, in
Section 10.0 which is summarized as follows:
The selected remedy for groundwater associated with LF-2 and LF-3/CAP is Minimal
Action (Alternatives LF-2-2 and LF3-2 of the FS). In addition to the source control
remedy outlined in the OU2 ROD (ABB-ES, I994b), Minimal Action for LF-2 and LF-
3/CAP will include institutional controls, downgradient groundwater monitoring, and a
contingency plan for providing additional remedial measures. The Minimal Action is a
final remedy for the groundwater associated with LF-2 and LF-3/CAP.
Clean Up Levels
The USAF has established, in conjunction with the regulatory agencies, sine-specific
action levels protective of human health and the environment. These action levels huve
been established for LF-2 bedrock groundwater and LF-3/CAP bedrock and overburden
groundwater, based on background concentration, analytical detection limits, MCL's.
MEG's or risk calculations. Tables 10-1 and 10-2 in the Final ROD. list the compounds
and elements for which action levels have been set. as well as summaries of risk
associated with the sites included in this operable unit. The State concurs with the action
levels listed in the tables above.
The State's concurrence with 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 OU4). The State reserves any and all
rights to challenge any such finding of fact or conclusion of law in any other context.
Serving Maine People & Protecting Their Environment
AUGUSTA PORTLAND SANQOR PR6SOU6 ISLE
17 STA11 HOME STATION 318CANCOROAD • To HASAN ROAD 12JS CIMTWU. OAIVS. SCTWAT r*HK
AUGUST* MAINE 04333-00-.7 ?omLAND. ME (Ml03 SJ-^QR. ME 91.101 Pr<.HArej:is;xG. HOSPITAL STRIST
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-2-
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
operation, design and monitoring plans. This concurrence is also based upon the ^ *
understandings set forth in the attached Letter of Understanding dated September 2<
1996.
The MEDEP looks forward to working with the Department of the Air Force and the
USEPA to resolve the environmental problems posed by this site. If you need additional
information, do not hesitate to contact myself or Mark Hyland.
Sincerely,
/^Edward 0. Sullivan
/^Department of Environmental Protection
attachment
pc: Mark Hyland, MEDEP
Mike Nalipinski, EPA
Hank Lowman, BCA
ONAALAN/dlb
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AMOA.EW K.ETTEAE*
ATTORNEY OeCRAL
84 HAUOW ST. fcu fux*
BAKOOt, UAIKC 04401
STATE OP MAINE S® Bffl
DEPARTMENT OF THE ATTORNEY GENERAL
6 SUTB HOUSE STATION
AUGUSTA. MAINZ 04333-0006
September 27, 1996
By Facsimile
A. DiBicouo, Esquire
U.S. EPA - Jtegiorv-I
JFK Federal Bulging
1 Congress Street
Boston, Massachusetts 02203-2211
Claire Biunno, Esquire
Assistant Chief Counsel
Air Force Bade Conversion Agency
1700 North Moore Street
Arlington. Virginia 22209-2808
Re: Letter of Uadirtfaading Concerning OUoVLorffig Air Force Base
Dear Bob and Claire:
Tht purpose of this letter is to document tha understanding reached by the
parted to the Loring Air Force Base Intaragency Agreement (TAG*) with regard to
the draft Kscord of Decision (TWD') for Operable Unit 4 (*CfU4"). As you know, a
dispute aross among the parties as to whether Maine's Maximum Exposure
Guidelines ("MEGs") should be considered as Applicable or Appropriate and
Relevant Laws (~ARAR5") at this Operable Unit. In order to avoid delaying
signature of the ROD/ the project managers have developed action levels for
compounds of concern at OU4 as shown on Tables 10-1 and 10-2 of the ROD.
The parti«» agree that tlteve action levels are only for the purpose of triggering
the contingency action described in five ROD and are not meant to be a
determination that MEGs are AEARs. The parties further agree that by entering this
agreement, no party waives any dcfanw or claim or effects any Itgal position with
regard to the MEG» » ARAR» U»ue. By way of example/ and not by way of
limitation, this agreement ir^y not be u»«d by any of the signatory parties In any
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OC/i/Uciiif Air POM* B«M
(MBG» - ARARc) dispute which may aziae at any other operable unit, aj 0vid«noe
that the State has failed to tw coosbtant with ngatd to d«dgnating MBGf u AKAR*.
Please rrview thto Letter of Undvatandin^ carefullv and Indicate your
approve! by aifning and ditiftg this Utter of Undemanding where indicated The
State of Main*'! concurrence tetter for the OU4 ROD will incorporate thl* Letter of
Understanding.
Very truly your*.
J. KARN1SH
Aieiatant Attorney General
DJH/tt
oc Naji
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Ute of UadftuM
ut
-3-
SE£N AND AGREED It*
Dated;
Dated;
DfiNNB J. HARNKH
Asalitant Attorney General
For thtStata of Maine
Senior Astiii&nt Regional Counsel
US.EPA-KegJoaI
For the U5. EPA
Dated:
CLAIRE BIUNNO
Affliitant Chief Counaol
Air Pprce Daoe Converalon Agency
For the US. DOD
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