PB96-964411
EPA/ROD/R08-96/123
October 1996
EPA Superfund
Record of Decision:
Ellsworth Air Force Base,
Operable Unit 7, Rapid City, SD
6/7/1996
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Final
Record of Decision for
Remedial Action at Operable Unit 7
Ellsworth Air Force Base, South Dakota
United States Air Force
Air Combat Command
Ellsworth Air Force Base
Project No.: FXBM9.47002
June 1996
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Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South Dakota
TABLE OF CONTENTS
Chapter - Page
1. DECLARATION FOR THE RECORD OF DECISION 1
1.1 SITE NAME AND LOCATION 1
1.2 STATEMENT OF BASIS AND PURPOSE 1
1.3 ASSESSMENT OF THE SITE 1
1.4 DESCRIPTION OF SELECTED REMEDY 1
1.5 STATUTORY DETERMINATION 2
1.6 SIGNATURE AND AGENCY CONCURRENCE ON THE REMEDY 3
2. DECISION SUMMARY 1
2.1 SITE NAME AND LOCATION 1
2.2 OPERABLE UNIT 7 (OU-7) DESCRIPTION/HISTORY AND
REGULATORY OVERSIGHT ACTIVITIES 1
2.2.1 Description/History .....1
2.2.2 Regulatory Oversight Activities 2
2.3 HIGHLIGHTS OF COMMUNITY PARTICIPATION 3
2.4 SCOPE AND ROLE OF RESPONSE ACTION 4
2.5 SITE CHARACTERISTICS 5
' 2.5.1 Surface Soils 5
2.5.2 Subsurface Soils 6
2.5.3 UST Pit Soils 7
2.5.4 Sediment 7
2.5.5 Surface Water , 8
2.5.6 Ground Water 9
2.6 SITE RISK SUMMARY 10
2.6.1 Human Health Risks 10
2.6.2 Ecological Risks... 11
2.7 DESCRIPTION OF ALTERNATIVES 12
2.8 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 14
2.8.1 Overall Protection of Human Health and the Environment 15
2.8.2 Compliance with ARARs .....15
2.8.3 Long-Term Effectiveness and Permanence 17
2.8.4 Reduction of Toxicity, Mobility, and Volume through Treatment 17
. 2.8.5 Short-Term Effectiveness 17
2.8.6 Implementability 18
. 2=8.7 Cost.... : 18
2.8.8 State Acceptance 21
2.8.9 Community Acceptance 21
2.9 SELECTED ALTERNATIVE ..-. 21
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Final Record of Decision Operable Unit 7
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2.10 STATUTORY DETERMINATIONS 23
2.10.1 Protection of Human Health and the Environment 23
2.10.2 Compliance with ARARs 24
2.10.3 Cost Effectiveness 24
2.10.4 Utilization of Permanent Solutions and Alternative Treatment
Technologies to the Extent Possible 24
2.10.5 Preference for Treatment as a Principal Element 24
2.11 DOCUMENTATION OF SIGNIFICANT CHANGES 24
3. LIST OF ACRONYMS AND ABBREVIATIONS... '. 1
APPENDICES
Appendix A Figures
Appendix B Responsiveness Summary
LIST OF TABLES
Table 2-1 Evaluation of Federal and State ARARs that Might Apply to OU-7,
Ellsworth Air Force Base, South Dakota
LIST OF FIGURES
Figure 2-1 Area Location Map
Figure 2-2 Site Location Map
Figure 2-3 OU-7 Location Map
Figure 2-4 Alternatives 2 and 5 Institutional Controls for Soil and Ground Water
OU-7 (LLRWB)
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Final Record of Decision Operable Unit 7
Ells\vorth Air Force Base, South Dakota
1. DECLARATION FOR THE RECORD OF DECISION
1.1 SITE NAME AND LOCATION
Operable Unit 7 (OU-7), Weapons Storage Area, Ellsworth Air Force Base (EAFB),
National Priority List Site
Meade and Pennington Counties, South Dakota
1.2 STATEMENT OF BASIS AND PURPOSE
This decision document describes EAFB's selected remedial action for Operable Unit 7 (OU-7),
in accordance with the Comprehensive Environmental Response, Compensation and Liability Act
of 1980 (CERCLA), as amended by the Superfund Amendments and Reauthorization Act of 1986
(SARA), and the National Oil and Hazardous Substances Pollution Contingency Plan (NCP).
This decision is based on the contents of the Administrative Record for OU-7, EAFB. The U.S.
Environmental Protection Agency (EPA) and the South Dakota Department of Environment and
Natural Resources (SDDENR) concur with the selected remedial action.
1.3 ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from OU-7, if not addressed by
implementing the response action selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to public health, welfare, or the environment.
1.4 DESCRIPTION OF SELECTED REMEDY
Twelve potentially contaminated areas, or operable units, have been identified at EAFB. This
ROD is for a remedial action at OU-7 and is the 10th ROD for EAFB.
The selected alternative for soils, institutional controls, includes the following major components:
Institutional controls for future land use;
An extensive records search will be performed that may provide additional information
relating to the burial trenches. A removal action might be used to address waste within
the trenches if the weight of evidence from this records search combined with previous
information identifies and warrants this type of remedial activity.
The selected alternative for ground water, institutional controls with additional monitoring,
includes the following major components:
Institutional controls for ground water use;
Implementing a long-term ground-water monitoring and maintenance program.
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Final Record of Decision Operable Unit 7
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Implementation of the remedy will reduce the future risk to human health and the environment to
acceptable levels.
1.5 STATUTORY DETERMINATION
The selected remedy is protective of human health and the environment, complies with Federal
and State of South Dakota requirements that are legally applicable or relevant and appropriate to
the remedial action, and is cost-effective. This remedy utilizes permanent solutions to the
maximum extent practicable for OU-7. However, because treatment of the principal threats of the
OU was not found to be necessary or cost effective, this remedy does not satisfy the statutory
preference for treatment as a principal element. The fact that there are no apparent on-site hot
spots or plumes that represent major sources of contamination preclude a remedy in which
contaminants could be treated effectively.
Because this remedy will result in hazardous substances remaining on site within the soil and
ground water at low levels, a review will be conducted no less often than every five years after
signing of the ROD to ensure that the remedy continues to provide adequate protection of human
health and the environment.
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Final Record of Decision Operable Uni: 7
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1.6 SIGNATURE AND AGENCY CONCURRENCE ON THE REMEDY
~^\ /"
i /I
/ :
BRETT M. DULA Date
Lieutenant General, USAF
Vice Commander
JACK W. McGRAW Date
Acting Regional Administrator
U.S. Environmental Protection Agency Region 8
NETTIE H. MYERS, Secretary Date
Department of Environment and Natural Resources
State of South Dakota
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Final Record of Decision Operable Unit 7
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1.6 SIGNATURE AND AGENCY CONCURRENCE ON THE REMEDY
BRETT M. DULA Date
Lieutenant General, USAF
Vice Commander
JApC W. McGRAW Date7
£ting Regional Administrator
U.S. Environmental Protection Agency Region 8
NETTIE H. MYERS, Secretary Date
Department of Environment and Natural Resources
State of South Dakota
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Final Record of Decision Operable Unit 7
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The selected alternative for ground water, institutional controls with additional monitoring,
includes the following major components:
Institutional controls for ground water use;
Implementing a long-term ground-water monitoring and maintenance program.
Implementation of the remedy will reduce the future risk to human health and the environment to
acceptable levels.
1.5 STATUTORY DETERMINATION
The selected remedy is protective of human health and the environment, complies with Federal
and State of South Dakota requirements that are legally applicable or relevant and appropriate to
the remedial action, and is cost-effective. This remedy utilizes permanent solutions to the
maximum extent practicable for OU-7. However, because treatment of the principal threats of
the OU was not found to be necessary or cost effective, this remedy does not satisfy the statutory
preference for treatment as a principal element. The fact that there are no apparent on-site hot
spots or plumes that represent major sources of contamination preclude a remedy in which
contaminants could be treated effectively.
Because this remedy will result in hazardous substances remaining on site within the soil and
ground water at low levels, a review will be conducted no less often than every five years after
signing of the ROD to ensure that the remedy continues to provide adequate protection of human
health and the environment.
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Final Record of Decision Operable Unit 7
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1.6 SIGNATURE AND AGENCY CONCURRENCE ON THE REMEDY
BRETT M. DULA
Lieutenant General, USAF
Vice Commander
Date
JACK W. McGRAW
Acting Regional Administrator
U.S. Environmental Protection Agency Region 8
Date
NETTIE H. MY^RS, Sec,
Department of Environnn
State of South Dakota
Date
'atural Resources
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Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South Dakota
2. DECISION SUMMARY
2.1 SITE NAME AND LOCATION
EAFB is a U.S. Air Force (USAF) Air Combat Command (ACC) installation located 12 miles
east of Rapid City, South Dakota, and adjacent to the small community of Box Elder (Figure 2-1).
EAFB covers approximately 4,858 acres within Meade and Pennington Counties and includes
runways and airfield operations, industrial areas, housing and recreational facilities (Figure 2-2).
Open land, containing a few private residences, lies adjacent to EAFB on the north, south, and
west, while residential and commercial areas lie to the east of the Base.
2.2 OPERABLE UNIT 7 (OU-7) DESCRIPTION/HISTORY AND REGULATORY
OVERSIGHT ACTIVITIES
2.2.1 Description/History
EAFB was officially activated in July 1942 as the Rapid City Army Air Base, a training facility
for B-17 bomber crews. It became a permanent facility in 1948 with the 28th Strategic
Reconnaissance Wing as its host unit. Historically, EAFB has been the headquarters of
operations for a variety of aircraft, as well as the Titan I Intercontinental Ballistic Missile and the
Minuteman I and Minuteman n missile systems. The Air Force has provided support, training,
maintenance, and/or testing facilities. Presently, the 28th Bombardment Wing (B-1B bombers)
and the 99th Tactics and Training Wing are the host units of EAFB.
OU-7, 1 of 12 contamination study areas (Figure 2-2), includes the Low-Level Radioactive
Waste Burial (LLRWB) site located in the Weapons Storage Area (WSA) at the northern end of
the Base. The WSA covers approximately 65 acres and is currently active. The complex
included two storage buildings with vaults, a maintenance building, three other
assembly/maintenance buildings, several storage igloos, two waste burial pit areas, five
wastewater underground storage tanks (USTs), and 16 heating fuel USTs (Figure 2-3). The
wastewater USTs were used to store water from the wash-down and cleaning of nuclear weapons
that drained through the floor drains into the USTs.
Radioactive wastes were generated at EAFB between 1952 and 1962. The five wastewater USTs
and 16 heating fuel USTs were removed in 1993 as part of a Base tank removal program.
Although historical records indicate that there were two waste burial pits, the exact locations are
not known. No available information has indicated that any ordnance or explosive radioactive
wastes were disposed of at OU-7. However, it is possible that the disposal areas might contain
this type of material.
The topography at OU-7 gently slopes toward the west and southwest away from the high plateau
located in the northeastern corner of the WSA. Surface-water drainage from OU-7 generally
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flows into drainages directed to Boxelder Creek. Some surface water flows off Base to the east,
northeast, and southeast of the OU.
OU-7 surface geology generally consists of a surface layer of silty clay, approximately 3 to 6 feet
thick, underlain by a layer of silty sandy gravel to clayey gravel, 4 to 27 feet thick. These layers
overlie the Pierre Shale Formation. Depth to shallow ground water at OU-7 ranges from
approximately 10 to 31 feet.
The shallow aquifer at EAFB is considered a potential drinking water source and possibly
discharges to the surface. The ground water is classified as having a beneficial use as a drinking
water supply suitable for human consumption (S.D. Chapter 74:03:15, Ground-Water Quality
Standards).
Deeper bedrock aquifers also exist beneath EAFB. These deeper aquifers are separated from the
shallow aquifer by 800 feet of impermeable clays and silts. In the past, EAFB utilized these
deeper aquifers for its water supply. Presently, EAFB obtains its potable water from the Rapid
City Municipal Distribution System.
The petroleum-contaminated soil from the fuel oil UST near Building 88316 is underneath the
building's structure and is being addressed under a State-directed UST investigation. Therefore,
the alternatives addressed in the FS do not need to meet SDDENR criteria for petroleum-
contaminated soil (SD 74:03:32).
2.2.2 Regulatory Oversight Activities
Environmental investigation activities at EAFB were initiated by the Air Force in 1985 through an
Installation Restoration Program (IRP) Phase I Installation Assessment/Records Search and Phase
II Confirmation/Quantification. The Phase I study, dated September 1985, identified a total of 17
locations at EAFB where releases involving hazardous substances potentially occurred.
In Phase II of the IRP investigation, field activities included soil vapor surveys, geophysical
surveys, surface and subsurface soil sampling, ground-water sampling, ground-water hydrologic
testing, and ecological investigations.
On August 30, 1990 (55 Federal Register 35509), EAFB was listed on the EPA's National
Priority List (NPL). A Federal Facilities Agreement (FFA) was signed in January 1992 by USAF,
EPA, and the State of South Dakota (State) and went into effect on April 1, 1992. The FFA
establishes a procedural framework and schedule for developing, implementing, and monitoring
appropriate response actions for EAFB in accordance with CERCLA, as amended by SARA, and
the NCP. It also states the oversight procedures for EPA and the State to ensure USAF
compliance with the specific requirements. The FFA identified 11 potential source-area operable
units as well as a Base-wide ground-water operable unit.
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Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South Dakota
Listing on the NPL and execution of the FFA required the USAF to perform a remedial
investigation/feasibility study (RI/FS) to investigate the 12 operable units. In 1993 and 1994, an
extensive RI field program was conducted to characterize conditions at OU-7. The program
included a surface geophysical survey, a surface radiological survey, completion of 16 soil
boreholes, installation of two ground-water monitoring wells, soil sampling of five wastewater
UST excavations, assessment of human health risks, and review and compilation of previous IRP
investigations. Collection and laboratory analysis of soil, ground-water, surface-water, and
sediment samples were included in the RI field program.
2.3 HIGHLIGHTS OF COMMUNITY PARTICIPATION
Community relations activities that have taken place at EAFB to date include:
FFA process. After preparation of the FFA by the USAF, EPA, and SDDENR, the
document was published for comment. The FFA became effective April 1, 1992.
Administrative Record. An Administrative Record for information was established in
Building 8203 at EAFB. The Administrative Record contains information used to
support USAF decision making. All the documents in the Administrative Record are
available to the public.
Information repositories. An Administrative Record outline is located at the Rapid
City Library (public repository).
Community Relations Plan (CRP). The CRP was prepared and has been accepted by
EPA and the State of South Dakota and is currently being carried out. An update to
this plan will be prepared in 1996.
Restoration Advisory Board (RAB). The RAB has been formed to facilitate public
input in the cleanup and meets quarterly. In addition to USAF, EPA, and South Dakota
oversight personnel, the RAB includes community leaders and representatives from the
surrounding area.
Mailing list. A mailing list of all interested parties in the community is maintained by
EAFB and updated regularly.
Fact sheet. A fact sheet describing the status of the IRP at EAFB was distributed to
the mailing list addressees in 1992.
Open house. An informational meeting on the status of the IRP and other
environmental efforts at EAFB was held on May 6, 1993. This type of open house
meeting format was also used during the November 16, 1995 Restoration Advisory
Board meeting to present information.
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Newspaper articles. Articles have been written for the Base newspaper regarding IRP
activity.
Proposed Plan. The proposed plan on this action was distributed to the mailing list
addressees for their comments.
A public comment period was held from December 28, 1995 to January 27, 1996, and a public
meeting was held on January 11, 1996. At this meeting, representatives from EAFB answered
questions about the remedial action. A response to the comments received during this period is
included in the Responsiveness Summary, which is'part of this ROD.
This ROD is based on the contents of the Administrative Record for OU-7, in accordance with
CERCLA, as amended by SARA, and the NCP. The RI/FS reports and the Proposed Plan for
OU-7 provide information about OU-7 and the selected remedy. These documents are available
at the Information Repositories at EAFB and the Rapid City Public Library.
2.4 SCOPE AND ROLE OF RESPONSE ACTION
The FFA identified 11 potential source area operable units (OUs) as well as a Base-wide
ground-water operable unit. The 12 operable units are identified as follows:
OU-1 Fire Protection Training Area
OU-2 Landfill Nos. 1 and 6
OU-3 Landfill No. 2
OU-4 Landfill No. 3
OU-5 Landfill No. 4
OU-6 Landfill No. 5
OU-7 Weapons Storage Area
OU-8 Explosive Ordnance Disposal Area (Pramitol Spill)
OU-9 Old Auto Hobby Shop Area
OU-10 North Hangar Complex .
OU-11 Base-wide Ground Water
OU-12 HardfillNo. 1
This ROD documents the selected remedy for the preferred remedial action (RA) at OU-7 and is
the 10th ROD for EAFB. The remedial action objectives (RAOs) are to reduce the potential risks
posed by contaminants in soils and to prevent ingestion of ground water containing chemicals
that are risk drivers at concentrations exceeding maximum contaminant levels (MCLs).
A focused approach has been applied to the development of the remedial alternatives. The
alternatives that were developed focused on remedy components most important for attaining the
remedial objectives. While there is some risk associated with the contamination observed at the
OU, it is apparent that the levels are not indicative of a major source or release of contamination.
The known sources of contamination have been removed and mitigated (i.e., wastewater and
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fuel-oil USTs have been removed). Other contaminated media that are not directly associated
with a known release or known contamination source have been identified. The reported
disposal trenches with low-level radiological waste have not been located. Therefore, when
examining source area remedial action options for soil, emphasis was placed on evaluating
different methods of eliminating exposure routes by containing or removing the contaminated
media or controlling the area's activities. During examination of ground-water control
alternatives, emphasis was placed on evaluating different methods for monitoring water quality
and control and removal of contaminants in ground water.
An extensive records search will be performed that may provide information relating to the burial
trenches and, if necessary, remediation will be performed as a removal action.
2.5 SITE CHARACTERISTICS
This section describes the presence and distribution of contaminants at OU-7 as a result of past
activities. Inorganic and radionuclide concentrations in soils and sediment were compared to
estimated background concentrations. If detected, organic compounds are discussed in this
section. For surface water and ground water, some applicable or relevant and appropriate
requirements (ARARs) do exist for all types of analytes. Therefore, in addition to detected
organics and comparison of inorganics and radionuclides to background levels, exceedances of
ARARs are discussed. All ARARs and estimated background concentrations are presented in
detail in the FS report.
An electromagnetic (EM) survey and a radioactivity screening survey were performed to
determine the locations of the waste burial sites. However, the results of these surveys did not
reveal definitive anomalies that were indicative of the exact locations of the buried trenches.
Based on findings from a subsequent radiological investigation for OUs 2 and 7 performed in
May 1995, an anomaly was noted south of Building 88304. The report indicated that the
observed radiation levels could be due to normal variations in background levels, construction
materials buried in the area, or buried radioactive waste.
2.5.1 Surface Soils
2.5.1.1 Volatile Organic Compounds (VOCs)
Three VOCs were reported in surface soil samples for OU-7. Methylene chloride was reported in
3 of 20 samples with a maximum concentration of 38 micrograms per kilogram (ug/kg); toluene
was reported in 7 of 20 samples with a maximum concentration of 20 ug/kg; and
octamethyltetracyclosiloxane (OMTCS), a tentatively identified compound (TIC), was reported
in 16 of 20 samples with a maximum concentration of 780 ug/kg. OMTCS is a laboratory
contaminant. No specific pattern of VOC contamination exists in the surface soil.
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2.5.1.2 Inorganic Analytes
Thallium was the inorganic analyte most frequently found above background levels, with a
maximum concentration of 0.41 milligrams per kilogram (mg/kg). The elevated concentrations
of thallium were reported in samples collected near the monitoring wells and near the UST
disposal lines. Lead and manganese were also reported above background levels with maximum
concentrations of 56.8 mg/kg and 5,570 mg/kg, respectively.
2.5.1.3 Radioactive Analytes
Although radionuclides were sometimes detected in surface soils, the concentrations at OU-7 are
at this time considered to be within the normal background range due to natural variations in soil
types and geological characteristics,. The original gross alpha background concentrations used
for comparison of surface soils range from 8.17 pCi/g to 14.49 pCi/g. To verify this assumption,
a long-term background radiological investigation is ongoing, and the results of this investigation
may affect the evaluation of soil at the OU.
2.5.2 Subsurface Soils
2.5.2.1 Volatile Organic Compounds
Three VOCs were reported in the soil boring subsurface samples at OU-7. Methylene chloride
was reported in 3 of 18 samples with a maximum concentration of 24 ug/kg, toluene was
reported in 9 of 18 samples with a maximum concentration of 7 ug/kg, and OMTCS was
reported as a TIC in 11 of 18 samples with a maximum concentration of 730 ug/kg.
2.5.2.2 Inorganic Analytes
Thallium and manganese were the inorganics found most frequently above background (8 of 10
samples and 10 of 18 samples with maximum concentrations of 0.36 mg/kg and 7,900 mg/kg,
respectively). Arsenic was reported above background in 8 of 18 soil boring subsurface samples
with a maximum concentration of 146 mg/kg.
2.5.2.3 Radioactive Analytes
Although radionuclides were detected in subsurface soils, the concentrations at OU-7 are at this
time considered to be within the normal background range due to natural variations in soil types
and geological characteristics. The original gross alpha background concentrations used for
comparison of subsurface soils range from 12.28 picocuries per gram (pCi/g) to 18.16 pCi/g. To
verify this assumption, a long-term background radiological investigation is ongoing, and the
results of this investigation may affect the evaluation of soil at the OU.
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2.5.3 UST Pit Soils
2.5.3.1 Volatile Organic Compounds
Two VOC analytes were reported above detection limits in UST pit soil samples at OU-7.
Methylene chloride was detected in 4 of 11 samples with a maximum concentration of 11 ug/kg,
and OMCTS was detected in 6 of 11 samples with a maximum concentration of 210 ug/kg. The
heating fuel UST investigation conducted separately indicates the presence of benzene, toluene,
ethylberizene, and xylene (BTEX) compounds in soils located near the USTs.
2.5.3.2 Semivolatile Organic Compounds (SVOCs)
Ten SVOCs were reported in UST pit soil samples above detection limits. Dl-n-butylphthalate
was reported in all 11 samples with a maximum concentration of 1,800 ug/kg, fluoranthene and
prometon were reported in 3 of 11 samples with maximum concentrations of 58 ug/kg and 310
ug/kg, respectively, and pyrene was reported in 2 of 11 samples with a maximum concentration
of 48 ug/kg. No specific pattern of SVOC contamination exists in the UST pit soils.
2.5.3.3 Inorganic Analytes
Six inorganic analytes were reported above the background range in UST pit soils, including
seven exceedances for manganese with a maximum concentration of 4,170 mg/kg. The
remaining analytes that exceeded background were arsenic with a maximum concentration of
24.8 mg/kg, barium with a maximum concentration of 623 mg/kg, calcium with a maximum
concentration of 86,500 mg/kg, vanadium with a maximum concentration of 51.8 mg/kg, and
thallium with a maximum concentration of 0.3 mg/kg.
2.5.3.4 Radioactive Analytes
Although radionuclides were detected in UST pit soils, the concentrations at OU-7 are at this
time considered to be within the normal background range due to natural variations in soil types
and geological characteristics. To verify this assumption, a long-term background radiological
investigation is ongoing, and the results of this investigation may affect the evaluation of soil at
the OU.
2.5.4 Sediment
2.5.4.1 Volatile Organic Compounds
Three VOCs were detected in sediment samples at OU-7. Chloroform was found at all three
sampling locations with a maximum concentration of 36 ug/kg, methane at two locations with a
maximum concentration of 250 ug/kg, and carbon disulfide at one location with a maximum
concentration of 79 ug/kg.
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2.5.4.2 Inorganic Analytes
Several inorganic analytes were detected in sediment samples, and most exceed the background
levels for total soils." The maximum concentrations are as follows: aluminum - 30,800 mg/kg;
barium - 515 mg/kg; beryllium - 1.9 mg/kg; calcium - 349,000 mg/kg; total chromium - 39.7
mg/kg; copper - 54.8 mg/kg; lead - 90.8 mg/kg; magnesium - 17,000 mg/kg; manganese - 3,320
mg/kg; nickel - 65.9 mg/kg; potassium - 7,730 mg/kg; sodium - 3,590 mg/kg; vanadium - 92.6
mg/kg; zinc - 436 mg/kg; selenium - 2.1 mg/kg; and thallium - 0.86 mg/kg. Total soil
background levels were used for comparison because background concentrations for inorganics
in sediment have not been estimated.
2.5.4.3 Radioactive Analytes
Gross alpha, gross beta, and gamma emitters were detected in sediment samples with maximum
concentrations of 12.6±3 pCi/g, 25±5 pCi/g, and 0.86±0.167 pCi/g, respectively, but were below
the background concentrations for total soils. Total soil background levels were used for
comparison because background concentrations for radionuclides in sediment have not been
estimated. A long-term background radiological investigation is ongoing, and the results of this
investigation may affect the evaluation of sediment at the OU.
2.5.5 Surface Water
2.5.5.1 Volatile Organic Compounds
Two surface-water samples were collected from the ephemeral pond at OU-7. Chloromethane
was the only VOC detected in both samples with a maximum concentration of 6 ug/L. There are
no ARARs for chloromethane in surface water.
2.5.5.2 Inorganic Analytes
Several inorganics were detected in the surface-water samples and were compared to ARARs
(State ambient water quality criteria). The maximum concentration for arsenic was 3.2
micrograms per liter (ug/L). The RI report compares the detected arsenic concentrations to a
water quality standard of 0.0022 u.g/L. However, the reported standard in the RI is for human
consumption of fish and would apply only if the water body had a beneficial use classification for
recreation including fishing. Although the pond is not classified or used as a drinking water
supply, the MCL for arsenic (50 fig/L) is more stringent than the Federal freshwater acute and
chronic criteria (360 u.g/L and 190 u,g/L, respectively) and can be used as the ARAR. The
detected arsenic concentrations are well below the MCL for arsenic. For all other constituents
that have ARARs. the ARARs were not exceeded.
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2.5.5.3 Radioactive Analytes
Gross alpha, gross beta, and gamma emittors were also detected in the surface-water samples
with maximum concentrations of 3.2±0.6 pCi/g, 12±2 pCi/g, and 2.93±7.53 pCi/g, respectively,
and were compared to ARARs. The concentrations of radioactive analytes are below the
standards. A long-term background radiological investigation is ongoing, and the results of this
investigation may affect the evaluation of surface water at the OU.
2.5.6 Ground Water
2.5.6.1 Volatile Organic Compounds
Two monitoring wells were installed at OU-7 in 1993, and three ground-water samples were
collected (one from each of the newly installed wells and one from an existing upgradient well).
The only VOCs detected were chloromethane and trichloroethylene (TCE). Chloromethane was
reported in all three samples with a maximum concentration of 0.8 ng/L, but the ARAR (MCL)
for chloromethane was not exceeded. TCE was reported at a maximum concentration of 9 ug/L,
exceeding the National Primary Drinking Water Regulations (NPDWR) standard (or MCL) and
State Ground Water Quality Standard of 5 ug/L. In addition, ground-water sampling performed
as part of the OU-11 sitewide ground-water investigation at OU-7 to determine the extent of the
reported TCE contamination also detected TCE in well MW930702 exceeding the MCL at a
concentration of 32 ug/L. However, additional field screening ground-water samples collected
nearby found no detections, indicating that a plume does not exist.
2.5.6.2 Inorganic Analytes
Twelve inorganic analytes were detected by total analysis, and 12 analytes were detected in the
dissolved phase. Dissolved antimony slightly exceeded the NPDWR standard for one sample and
MCL goal (MCLG) for all three samples, with a maximum concentration of 6 ug/L. However,
the detected antimony concentrations were below the background levels. No other ARARs for
inorganics were exceeded, including State Ground Water Quality Standards. .Antimony is among
several inorganics believed to occur naturally at elevated levels in the area.
2.5.6.3 Radioactive Analytes
Gross alpha, gross beta, and gamma emittors were detected in the ground-water samples with
maximum concentrations of 26±5 pCi/g, 17±3 pCi/g, and 4.94±6.77 pCi/g, respectively, and were
compared to ARARs. The concentrations of gross beta and gamma emittors were below the
standards. Gross alpha concentrations exceeded the standard for two of the samples. However,
none of the radionuclides detected in ground water were above the background concentrations.
The gross alpha and gross beta background concentrations exceed the federal MCLs, while gross
alpha levels exceeded the State Ground Water Quality Standards. A long-term background
radiological investigation is ongoing. Any revaluation of the groundwater based on the results of
this investigation will occur as part of OU-11.
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2.6 SITE RISK SUMMARY
2.6.1 Human Health Risks
The selected alternative discussed in Section 2.9 will address the human health and ecological
risks presented in this section.
The assessment of human health risks for this OU considered the following topics:
(1) Contaminants of concern (COCs) in ground-water, surface-water, sediment, and soil
samples collected at OU-7;
(2) Current and future land-use conditions;
(3) Potential environmental pathways by which populations might be exposed;
(4) Estimated exposure point concentrations of chemical and radionuclide COCs;
(5) Estimated intake levels of the COCs;
(6) ToxicityoftheCOCs;and
(7) Uncertainties in the assessments of exposure, toxicity, and general risks.
Noncarcinogenic and carcinogenic risks were calculated for the following potential exposure
groups:
(1) Current EAFB maintenance personnel mowing grass on-site who ingest and have
dermal contact with surface soil;
(2) The future adult/child living on-site who ingests surface soil;
(3) The future adult/child living on-site who has dermal contact with surface soil and
ingests and showers with shallow ground water;
(4) The future adult/child living on-site who ingests surface water and sediment, has
dermal contact with surface water, and inhales volatile contaminants; and
(5) Future adult construction workers who excavate on-site for building residences who
ingest soil, inhale particulates, and inhale volatile contaminants.
A quantitative risk assessment was performed for the ground water, soil, sediment, and surface
water. The risk assessment evaluated potential effects on human health posed by exposure to
contaminants within OU-7. Carcinogenic risks were estimated as the incremental probability of
an individual developing cancer over a lifetime as a result of exposure to a potential cancer-
causing chemical. The acceptable risk range expressed as a probability is one cancer incident in
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ten thousand people to one cancer incident in a million people. This level of risk is also denoted
by 1 x 10"4 to 1 x 10~6. Risks within the acceptable risk range may or may not warrant remedial
action depending on site-specific circumstances. Risks below this range cannot be differentiated
from the background occurrence of cancer in human populations. Risks calculated in a risk
assessment are potential risks and are excess (i.e., over background) cancer risks due to exposure
from contaminants at the OU. Noncarcinogenic health risks are evaluated using the hazard index
(HI). If the HI is less than or equal to one, the contaminant concentration is considered an
acceptable level and it is generally assumed that the human population may be exposed to it
during a 30-year period without adverse health effects.
Some surface soil samples had concentrations of gross alpha and gross beta radioactivity
exceeding the soil background range. However, the risks associated with ingestion and
inhalation of, and dermal contact with, these contaminants by potential future residents and
construction workers are very small and within the acceptable range (1 x 10"4 to 1 x 10"6 or less).
Risks associated with construction worker exposure to gross alpha and gross beta and several
inorganic analyte (especially manganese) contaminants in UST pit soils are also minimal and
within the acceptable range. Although VOCs, inorganics, and radionuclides were detected in
sediment, the risks to potential future residents and construction workers from ingestion,
inhalation, and/or dermal contact are within the acceptable range. There are no unacceptable
risks to potential future residents and construction workers from ingestion and inhalation of, or
dermal contact with, contaminants in surface water or ground water. Based on the minimal risks
associated with contaminants in soils and ground water at the site, limited institutional controls
for these media are warranted.
2.6.2 Ecological Risks
An ecological risk evaluation of OU-7 was based on a combination of data and literature reviews,
field and laboratory analyses, analyte evaluation and screening, and preliminary risk screening.
Results of the evaluation indicate that OU-7 does not exhibit significant ecological value due to
its highly disturbed environment (OU-7 primarily consists of buildings, roads, and paved areas).
There are small areas of potential grassland and wetland habitats at the OU. A variety of animal
species may live, forage, or nest in OU-7 habitats. These species include various types of
invertebrates, amphibians, birds, and mammals. Terrestrial vegetation and soil faunal
communities do not reveal characteristics that indicate chemical-related impacts. This finding is
consistent with the relatively low levels of contaminants in the soil. Because of the altered
natural environment at OU-7, rare, threatened, or endangered species are unlikely to utilize the
area for more than brief, periodic habitat. Due to the low levels of contaminant concentrations,
the contaminants do not pose an unacceptable risk to these species. In addition, the limited
contact these species would have with the OU-7 area ensures unacceptable risk to a single
individual will not occur.
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Because of these considerations, an OU-specific ecological investigation and risk assessment was
not recommended or performed at OU-7. However, a Base-wide ecological risk assessment was
conducted as part of OU-11, and OU-7 has been included in this Base-wide evaluation. A
complete list of species that may visit the OU, and the Base-wide ecological risk assessment, is
presented in the Final Remedial Investigation Report, Operable Unit 11, Ellsworth Air Force
Base, South Dakota (USAF, 1995).
2.7 DESCRIPTION OF ALTERNATIVES
Using a focused approach to develop the remedial alternatives for OU-7, emphasis was placed on
eliminating or reducing exposures to contaminants in soil and ground water by containing or
removing the contaminated media or controlling the site's activities. The alternatives that were
developed were separated into those addressing soil and those addressing ground water:
Alternative I (Soil) - No Action
No action.
The no action alternative represents the baseline condition at OU-7 and refers to taking
no further action for the soil.
Alternative 2 (Soil) - Institutional Controls
Institutional controls for future land use;
An extensive records search will be performed that may provide additional information
relating to the burial trenches. A removal action might be used to address waste within
the trenches if the weight of evidence from this records search combined with previous
information identifies and warrants this type of remedial activity.
Alternative 3a (Soil) - Wastewater UST Soil Removal and Disposal at OU-4
Potentially contaminated soil would be delineated and excavated from the former
wastewater UST locations.
The UST piping and potentially contaminated soil surrounding the piping would be
excavated.
Removal of soil would consider contaminant levels based on risks associated with
manganese and radionuclides in soil.
The excavated soil and miscellaneous debris would be disposed of at the on-Base OU-4
landfill or could be hauled to the nearest RCRA landfill facility.
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Alternative 3b (Soil) - Waste Disposal Trenches Soil Removal and Disposal at OU-4
Potentially contaminated soil would be delineated and excavated from the suspected
waste disposal trench locations.
Removal of soil would consider contaminant levels based on risks associated with
manganese and radionuclides in soil.
The excavated soil and miscellaneous debris would be disposed of at the on-Base OU-4
landfill or could be hauled to the nearest RCRA landfill facility.
Alternative 4 (Ground Water) - No Action
No action.
The no action alternative represents the baseline condition at OU-7 and refers to taking
no further action for the ground water at OU-7.
Alternative 5 (Ground Water) - Institutional Controls with Additional Monitoring
Institutional controls for ground water use;
Implementing a long-term ground-water monitoring and maintenance program.
Alternative 6a (Ground Water) - Ground-Water Extraction Well/On-Base Wastewater
Treatment Plant/Discharge to Surface Water
Install a ground-water extraction well (pump) at MW930702 near the northeast corner
of the OU-7 boundary.
Install piping to convey extracted ground water to the nearest sanitary sewer line.
Treat extracted ground water at the existing on-Base sanitary wastewater treatment
plant for an estimated 5 years, and perform ground-water monitoring for an estimated
30 years.
Discharge treated ground water to the surface water drainage below the treatment plant.
Alternative 6b (Ground Water) - Ground-Water Recovery Trench/On-Base
Wastewater Treatment Plant/Discharge to Surface Water
Install extraction trench near well MW930702 near the northeast corner of the OU-7
boundary.
Install piping to convey extracted ground water to the nearest sanitary sewer line.
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Treat extracted ground water at the existing on-Base sanitary wastewater treatment
plant for an estimated 5 years, and perform ground-water monitoring for an estimated
30 years.
Discharge treated ground water to the surface water drainage below the treatment plant.
Alternative 6c (Ground Water) - Ground-Water Extraction Well/On-Site Treatment
Plant/Discharge to On-Base Wastewater Treatment Plant
Install a ground-water extraction well (pump) at MW930702 as stated in Alternative
6a.
Treat extracted ground water at an on-site portable carbon adsorption unit for an
estimated 5 years, and perform ground-water monitoring for an estimated 30 years.
Discharge treated ground water to the nearest sanitary sewer line and the on-Base
wastewater treatment plant.
2.8 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
The analysis of alternatives provides a narrower range of feasible remedial actions at OU-7. The
remedial action objectives (RAOs) for the site are as follows:
Soil
Reduce construction worker inhalation of surface and subsurface soil contaminants at
concentrations exceeding remediation goals.
Ground Water
Prevent ingestion of ground water containing contaminants at concentrations exceeding the
remediation goals.
The area of attainment for ground water is defined as the area that will achieve the RAOs after
remediation is completed. Ground water within the boundaries of OU-7 may be considered an
area of attainment.
Pursuant to Section 300.430(e)(9)(iii) of the revised NCP, the remedial action to be implemented
should be selected based on consideration of nine evaluation criteria. These criteria are as
follows:
1. Overall protection of human health and environment.
2. Compliance with ARARs.
3. Long-term effectiveness and permanence.
4. Reduction of toxiciry, mobility, or volume of contamination.
5. Short-term effectiveness.
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6. Implementability.
7, Cost.
8. State acceptance.
9. Community acceptance.
The following sections provide a brief review and comparison of the remedial alternatives
according to the NCP evaluation criteria.
2.8.1 Overall Protection of Human Health and the Environment
The assessment of this criterion considers how the alternatives achieve and maintain protection
of human health and the environment.
Alternatives I and 4 (no action alternatives for soil and ground water, respectively) do nothing to
reduce risk levels at OU-7. Alternatives 2 and 5 (institutional controls for soil and ground water,
respectively) reduce risk of exposures to soil and ground water by restricting site access and
restricting land use to eliminate primary receptor populations under future land use scenarios.
Alternative 5 also provides for additional monitoring to detect potential future contaminant
releases to ground water. Alternatives 3a and 3b eliminate potential exposure associated with
surface and subsurface soils and minimize the risk of the soil contributing contaminants to
ground water. Alternatives 6a, 6b, and 6c include remediation of the ground water to meet
ARARs.
2.8.2 Compliance with ARARs
Alternatives are assessed under this criterion in terms of compliance with ARARs. Applicable
requirements include cleanup standards, standards of control, and other substantive
environmental protection requirements, criteria, or limitations promulgated under Federal or
State laws that specifically address a hazardous substance, pollutant, contaminant, remedial
action, location, or other circumstances at a CERCLA site.
Relevant and appropriate requirements address problems or situations sufficiently similar to
those encountered at a CERCLA site that their use is well suited to the environmental and
technical factors at a particular site. ARARs are grouped into the following three categories:
Chemical-Specific ARARs are health or risk-based numerical values'or methodologies
that, when applied to site-specific conditions, result in establishment of the amount or
concentration that may be found in, or discharged to, the environment.
Location-Specific ARARs restrict the concentration of hazardous substances or the
conduct of activities solely because they are in specific locations such as flood plains,
wetlands, historic places, and sensitive ecosystems or habitats.
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Action-Specific ARARs are usually technology- or activity-based requirements or
limitations on actions taken with respect to hazardous wastes.
A summary evaluation of Federal and State ARARs pertinent to this remedial action is provided
in Table 2-1 at the end of Section 2.0. A narrative discussion of compliance with ARARs is
provided below for the alternatives considered.
Alternatives 1 and 4 (No Action for Soil and Ground Water):
Alternative 4 does not achieve ground-water ARARs, and alternatives 1 and 4 do not meet the
RAOs for OU-7. No action would be taken to prevent human contact with surface-soil and
ground-water contaminants. No Federal or State permits are required for these alternatives.
Alternative 2 (Institutional Controls for Soil):
Alternative 2 will not achieve ARARs because no ARARs exist for soils. However, it would
reduce potential exposure and subsequent risks associated with the soils at the OU by effectively
restricting site access and deterring unauthorized site entry. No Federal or State permits are
required for this alternative.
Alternative 5 (Institutional Controls for Ground Water):
Alternative 5 would reduce potential exposure and subsequent risks associated with ground water
at the OU by effectively restricting site access, deterring unauthorized site entry, and eliminating
ground-water consumption. Ground-water ARARs (MCLs) would not be met with this
alternative through active remediation. However, natural attenuation is likely to reduce existing
ground-water contamination levels below the MCL.
Alternatives 3a and 3b (Wastewater UST and Waste Disposal Trenches Soil Removal and
Disposal):
Alternatives 3a and 3b will not achieve ARARs because no ARARs exist for soils. However,
they would achieve risk-based cleanup levels and reduce the potential of contaminants from the
soil to migrate to ground water. Action-specific ARARs relating to the disposal of excavated soil
at the OU-4 landfill would include corrective action management unit (CAMU) regulations.
Land disposal restrictions (LDRs) would be the ARARs for the soil to be disposed of at an off-
site facility.
Alternatives 6a, 6b, and 6c (Ground Water Extraction/Treatment):
Alternatives 6a, 6b, and 6c would meet ground-water ARARs by treating the extracted ground
water to achieve MCLs. Sufficient ground water would be extracted and treated so that MCLs
would be met at the Base boundary.
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2.8.3 Long-Term Effectiveness and Permanence
The assessment of this criterion involves considering the long-term effectiveness of alternatives
in maintaining protection of human health and the environment after RAOs have been met.
Alternatives 1 -and 4 would not provide additional effectiveness or permanence in reducing the
potential for direct contact or ingestion of the soil or ground water. No further controls for the
OU would be developed under this alternative.
Alternatives 2 and 5 would provide for increased effectiveness of access restrictions (in addition
to the general EAFB access restrictions), thereby reducing risk of exposure to contaminants.
Permanency and reliability of these controls would be enhanced through long-term monitoring
and maintenance of the OU. Uncertainties exist with regard to the ability to provide long-term
access restrictions.
Alternatives 3a and 3b would provide the highest level of long-term effectiveness for soil.
Reduction of risk would be achieved by the removal of the soil that is driving the human health
risks associated with the soil. Unrestricted future land uses would be allowed.
Alternatives 6a, 6b, and 6c would offer a high level of long-term effectiveness for ground water.
Minimization of risk would be achieved by a reduction in the concentration of chemicals in the
ground water.
2.8.4 Reduction of Toxicity, Mobility, and Volume through Treatment
The assessment of this criterion involves considering the anticipated performance of specific
treatment technologies that an alternative may employ.
Alternatives 1, 2,4, and 5 would not provide for the reduction of toxicity, mobility, or volume of
the chemicals of concern in the soil and/or ground water. Alternatives 3a and 3b do not use
treatment technologies but reduce the mobility of the contaminants in soils by removal and
disposal/containment at the OU-4 landfill. Alternatives 6a, 6b, and 6c reduce the toxicity,
mobility, and volume of ground-water contaminants through extraction and treatment.
2.8.5 Short-Term Effectiveness
The assessment of this criterion considers the effectiveness of alternatives in maintaining
protection of human health and the environment during the construction of a remedy until RAOs
have been met.
The proposed alternatives are not expected to significantly impact worker or community health
and safety during the implementation period. Alternatives 3a and 3b might impact community
and worker health and safety somewhat through dust emissions during the initial construction
phase. Alternative 3b could, to a small degree, impact worker and community health and safety
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via hazardous air emissions and/or human contact with hazardous waste during potential
inadvertent radioactive waste intrusion. The impact could be minimized through dust mitigation
and adequate health and safety precautions during implementation.
2.8.6 Implementability
The assessment of this criterion considers the administrative and technical feasibility of
implementing the alternatives and the availability of necessary goods and services to fulfill the
response action.
Alternatives 1 and 4 would not be difficult to implement because no further action would be
undertaken.
Alternatives 2 and 5 require no special or unique activities and could be implemented using locally
available materials and contractors. Long-term monitoring would indicate whether additional
action is required in the future. Land use restrictions, annotations of base records and
administrative controls can be implemented at EAFB by various administrative means.
Alternatives 3 a and 3b could be implemented with standard construction equipment, materials,
and methods. Alternative 3b could potentially require radioactive waste specialists and equipment
to be on standby in case of inadvertent uncovering of radioactive waste materials.
Alternatives 6a, 6b, and 6c require no special or unique activities and could be implemented with
widely available equipment, materials, and methods. For alternatives 6a and 6b, the existing on-
Base wastewater treatment plant would be utilized to treat ground water. A single-pass trenching
system would likely be employed for the alternative requiring a ground-water recovery trench,
which is available from several venders. The portable carbon adsorption treatment system that
would be employed for Alternative 6c would be a small-volume unit and is also available from
several venders.
2.8.7 Cost
The assessment of this criterion considers the capital and operation and maintenance (O&M) costs
associated with each alternative. Alternatives are evaluated for cost in terms of both capital costs
and long-term O&M costs necessary to ensure continued effectiveness of the alternatives. Capital
costs .include the sum of the direct capital costs (materials and labor) and indirect capital costs
(engineering, licenses, permits). Long-term O&M costs include labor, materials, energy,
equipment replacement, disposal, and sampling necessary to ensure the future effectiveness of the
alternative. The objective of the cost analysis is to eliminate those alternatives that do not provide
measurably greater protection of human health and the environment for additional costs that may
be incurred.
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The total costs for Alternative No. 2 do not include costs for the extensive records review
relating to the burial trenches or any costs for the possible removal action. Costs have not been
included for ground:water treatment at the on-Base sanitary wastewater treatment plant for
Alternative Nos. 6a and 6b because these are included in (and would not significantly impact) the
Base operational costs. However, costs associated with the on-site carbon adsorption ground-
water treatment system have been included in Alternative 6c.
A summary of the costs for each alternative is as follows:
Alternative No. 1 (No Action - Soil)
Total Capital Costs
Total Annual (Sampling/Analysis/O&M) Costs
30- Year Present Value for Annual Costs
Annual Cost = SO
Years = 30
Discount Rates = 5%
TOTAL 30-Year Present Value
SO
$0
$0
$0
Alternative No. 2 (Institutional Controls Soil)
Total Capital Costs
Total Annual (Sampling/Analysis/O&M) Costs
30- Year Present Value for Annual Costs
Annual Cost = SO
Years = 30
Discount Rates = 5%
TOTAL 30-Year Present Value
$4,864
SO
SO
S4.864
Alternative No. 3a (Wastewater UST Soil Removal and Disposal at OU-4)
Total Capital Costs
Total Annual (Sampline/Analysis/O&M) Costs
30- Year Present Value for Annual Costs
Annual Cost = $0
Years = 30
Discount Rates = 5%
TOTAL 30-Year Present Value
$418.430
SO
$0
S4 18.430
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Alternative No. 3b (Waste Disposal Trenches Soil Removal and Disposal at OU-4)
Total Capital Costs
Total Annual (Sampling/Analysis/O&M) Costs
30- Year Present Value for Annual Costs
Annual Cost = $0
Years = 30
Discount Rates = 5%
TOTAL 30-Year Present Value
572,722
$0
$0
S72.722
Alternative No. 4 (No Action --Ground Water)
Total Capital Costs
Total Annual (Sampling/Analysis/O&M) Costs
30- Year Present Value for Annual Costs
Annual Cost = $0
Years = 30
Discount Rates = 5%
TOTAL 30-Year Present Value
$0
$0
$0
$0
Alternative No. 5 (Institutional Controls with Additional Monitoring Ground Water)
Total Capital Costs
Total Annual (Sampling/Analysis/O&M) Costs
30- Year Present Value for Annual Costs
Annual Cost = $60,000
Years = 30
Discount Rates = 5%
TOTAL 30-Year Present Value
$42,980
$60,000
$922,320
$965.300
Alternative No. 6a (Ground Water Extraction Well/On-Base Wastewater Treatment Plant/Discharge to
Surface Water)
Total Capital Costs
Total Annual (Sampling/Analysis/O&M) Costs
30-Year Present Value for Annual Costs
Annual Cost = $60,000
Years = 30
Discount Rates = 5%
TOTAL 30-Year Present Value
$121,500
$60,000
$922,320
$1.043.820
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Alternative No. 6b (Ground Water Recovery Trench/On-Base Wastewater Treatment Plant/Discharge to
Surface Water)
Total Capital Costs
Total Annual (Sampling/Analysis/O&M) Costs
30- Year Present Value for Annual Costs
Annual Cost = $60,700
Years = 30
Discount Rates = 5%
TOTAL 30- Year Present Value
$882,900
$60,700
$933,080
$1.815.980
Alternative No. 6c (Ground-Water Extraction Well/On-Site Treatment Plant/Discharge to On-Base
Wastewater Treatment Plant
Total Capital Costs
Total Annual (Sampling/Analysis/O&M) Costs
30- Year Present Value for Annual Costs
Annual Cost = $6 1,1 00
Years = 30
Discount Rates = 5%
TOTAL 30-Year Present Value
$84,200
$61,100
$939,290
$1.023.490
2.8.8 State Acceptance
The assessment of this criterion considers the State's preferences for or concerns about the
alternatives.
The State concurs with the selected remedy. The State provided comments on the RI/FS,
Proposed Plan, and this ROD. After incorporating adequate responses to the comments into the
respective documents, the State concurred with the remedy.
2.8.9 Community Acceptance
Comments offered by the public were used to assess the community acceptance of the proposed
alternative. The community expressed concerns about the selected remedy during the public
comment period. The questions and concerns of the community are described in detail in the
Responsiveness Summary, which is Appendix B of the ROD.
2.9 SELECTED ALTERNATIVE
Based on the requirements of CERCLA, comparative analysis of the nine criteria, public
comments, and consultation with EPA and the State, the Air Force has determined that the
selected alternative is a combination of Alternative 2, Institutional Controls for Soil and
Alternative 5, Institutional Controls for Ground Water with Additional Monitoring. This
alternative includes institutional controls in conjunction with comprehensive ground water
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monitoring and natural attenuation to evaluate and reduce potential future risk. Five-year reviews
of the remedy will be required because potential contaminants will remain at OU-7 following
completion of remedial action. Based on the results of this review ground water remediation may
be necessary if contaminants increase or the plume moves.
The following major components comprise Alternative 2:
Institutional controls for future land use;
An extensive records search will be performed that may provide additional information
relating to the burial trenches. A removal action might be used to address waste within
the trenches if the weight of evidence from this records search combined with previous
information identifies and warrants this type of remedial activity.
Alternative 5 includes the following major components:
Institutional controls for ground water use;
Implementing a long-term ground-water monitoring and maintenance program.
Institutional controls would be implemented to prevent human exposure to contaminated soil and
ground water. These controls will include: (1) issuing a continuing order by the Installation
Commander to restrict access to the site soils and to restrict or control temporary construction
activities unless proper protective equipment is worn; (2) filing a notice with the State of South
Dakota to recommend denial of water appropriation permit applications to install ground-water
wells within the WSA boundary and any area which may be affected by contaminants; (3)
annotation of base records in the event of property transfer.
A continuing order would be issued by the Installation Commander to restrict" access to or
disturbance of the soils and ground water as long as Ellsworth AFB owns the property.
Specifically, it would:
Restrict or place limitations on intrusive site activities, including the installation of any
new underground utilities or other construction activities in the area of the WSA; thus
preventing accidental exposures to construction workers.
. An existing fence would be maintained around the WSA as long as weapons storage
remains the use of this area, and warning signs would be posted at the former UST
locations and the waste disposal trench locations to deter unauthorized access.
Provide for the use of proper protective equipment, in the event that intrusion through
the site soils is required.
Continuing order requirements will be in effect as long as the property is owned by Ellsworth
AFB. In the case of the sale or transfer of the property within OU-7 by the United States to any
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other person or entity, the Air Force will place covenants in the deed which will restrict access
and prohibit disturbance of contaminated soils without approval of the United States. These
covenants will be in effect until removed upon agreement of the State of South Dakota, the U.S.
Environmental Protection Agency, and the U.S. Air Force or their successors in interest. The Air
Force will also include in the deed the covenants required by section 120(h)(3) of the
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), which
include (1) a warranty that the United States will conduct any remedial action found to be
required by law after the date of the transfer; (2) a right of access in behalf of EPA and the Air
Force or their successors in interest to the property to participate in any response or corrective
action that might be required after the date of transfer. The right of access referenced in the
preceding sentence shall include the State of South Dakota for purposes of conducting or
participating in any response or corrective action that might be required after the date of transfer.
These alternatives will meet the RAOs and reduce the potential risk at OU-7 by preventing future
exposure to contaminants in the soils and ground water. The selected alternative will be
protective of human health and the environment.
This alternative meets the statutory requirements of Section 121 of CERCLA as amended by
SARA. These statutory requirements include protectiveness of human health and the
environment, compliance with ARARs, cost effectiveness, and use of permanent solutions to the
extent practicable. The statutory preference for treatment is not satisfied; however, the selected
alternative reduces risk of impacts to human health and the environment.
2.10 STATUTORY DETERMINATIONS
The selected remedy meets the statutory requirements of CERCLA as amended by SARA. These
requirements include protection of human health and the environment, compliance with ARARs,
cost effectiveness, and use of permanent solutions to the extent practicable. The selected remedy
represents the best balance of tradeoffs among the alternatives considered.
The manner in which the selected remedy meets each of these requirements is described in the
following sections.
2.10.1 Protection of Human Health and the Environment
The selected remedy addresses health and environmental issues identified in the OU-7 RI report.
Specifically, the institutional controls alternative for soil and ground water achieves the
following goals:
Eliminates exposure to soil and ground-water contaminants by implementing
administrative actions that restrict site use and any intrusive activities.
Prevents unauthorized access to the area by maintaining a perimeter fence and
restricted access signs.
ip\310700S\dranrod.doc 2-23 April 30. 1996
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Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South Dakota
2.10.2 Compliance with ARARs
Alternatives 2 and 5 will meet requirements to reduce risks associated with site soils and ground
water to acceptable levels by providing access/development restrictions and controlling intrusive
site activities. Additional information about ARAR compliance is contained in Section 2.8.2.
2.10.3 Cost Effectiveness
The selected remedy provides overall effectiveness in reducing human health risks relative to its
costs. The selected ground-water remedy provides the most cost-effective alternative for ground-
water control.
2.10.4 Utilization of Permanent Solutions and Alternative Treatment Technologies to the
Extent Possible
The institutional controls and 30-year ground-water monitoring will provide long-term
prevention of exposure to contaminants in ground water.
A review of the selected remedy will be conducted every five years after signing of this ROD to
ensure that the remedy continues to provide adequate protection of human health and the
environment.
2.10.5 Preference for Treatment as a Principal Element
Treatment of the soil and ground water at the OU is not supported based on findings of the RI for
OU-7. No well-defined hot spots or contaminant plumes were present, and the risks associated
with OU-7 can be addressed by eliminating exposure to the contaminants in soil and ground
water by institutional controls.
2.11 DOCUMENTATION OF SIGNIFICANT CHANGES
The selected action, institutional controls for site soils and ground water with additional
monitoring of ground water, is somewhat different than the recommended alternative in the
Proposed Plan and Feasibility Study for OU-7. The alternative originally selected was
institutional controls for soils and ground water extraction/on-site treatment with a portable
carbon adsorption unit, and discharge to the existing sanitary sewer line and on-Base wastewater
treatment plant.
The primary reason for the change in the recommended alternative is that the FFA parties have
recently agreed, and public comments have recommended, that institutional controls for very
limited TCE contamination in ground water is the most cost-effective option. Natural
attenuation of the TCE is also anticipated.
ip\310700Mrafirod.doc 2-24 April 30. 1996
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Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South Dakota
Table 2-1
Evaluation of Federal and State ARARs that Might Apply to OU-7,
Ellsworth Air Force Base, South Dakota
Standard Requirement, Criteria, or Limitation
Citations
Description
A. Potentially Applicable or Relevint and Appropriate Federal Standards, Requirements, Criteria, and Limitations
Safe Drinking Water Act
National Primary Drinking Water Standards
National Secondary Drinking Water Standards
Maximum Contaminant Level Goals
Clean Water Act
Water Quality Criteria
Criteria and Standards for the National Pollutant Discharge
Elimination System
General Pretreaunent Regulations for Existing and New
Sources of Pollution
Guidelines Establishing Test Procedures for the Analysis of
Pollutants
42USC300g
40 CFR Part 141
40 CFR Part 143
Pub. L. No. 99-330, 100 Slat.
642(1986)
33 USC 1251-1376
40 CFR Part 131
40 CFR 125
40 CFR 403
40 CFR 136
ARAR Type
Applicability to OU-7
Establishes health-based standards for public water systems
(maximum contaminant levels).
Establishes welfare-based standards for the public water systems
(secondary maximum contaminant levels).
Establishes drinking water quality goals set at levels of unknown or
anticipated adverse health effects, with an adequate margin of
safety.
Chemical
Chemical
Chemical
Relevant and appropriate for Federal Class H aquifer.
Relevant and appropriate.
Relevant and appropriate.
Sets criteria for water quality based on toxicity to aquatic organisms
and human health.
Establishes criteria and standards for technology-based requirements
in permits under the CWA.
Establishes responsibilities of federal, state, and local government
and of the POTW in providing guidelines for and developing,
submitting, approving, and modifying state pretreatment programs.
Specifies standards for pretreatment.
Specifics analytical procedures for NPDES applications and reports.
Chemical
Chemical
Action
Action
Relevant and appropriate. Aquifer may be a Federal Class
1IA (discharge to surface water).
Applicable because of potential discharge stream or to
EAFB wastewater treatment plant.
Applicable because of potential discharge to EAFB
waslewater treatment plant.
Applicable because of treatment and discharge of ground
water.
Clean Air Act
National Primary and Secondary Ambient Air Quality
Standard
National Emission Standards for Hazardous Air
Pollutants
Solid Waste Disposal Facility Criteria
Land Disposal Restrictions
Guidelines for the Land Disposal of Solid Wast*
40 CFR Part 50
40 CFR Part 61
40 CFR Parts 257 and 258
40 CFR Part 268
40 CFR Part 241
Establishes standard for ambient air quality to protect public health
and welfare.
Establishes regulatory standard for specific air pollutants.
Sets forth revised minimum federal criteria for Municipal Solid
Waste Landfills (MSWLFs) for existing and new units.
Identifies hazardous wastes that are restricted from land disposal
and defines those limited circumstances under which a prohibited
waste may continue to be land disposed.
Establishes requirements and procedures for the disposal of solid
waste.
Action
Action
Action
Action
Action
Applicable.
Applicable. Several alternatives would require discharge to
the air following treatment.
Relevant and appropriate for addressing landfill closure
performance standards.
Relevant and appropriate. Alternatives may include the
disposal of residual waste due to treatment.
Relevant and appropriate for meeting landfill closure
standards.
tp\SW700fvlraflrtKl.doc
2-25
April 30. 1996
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Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South Dakota
Table 2-1 (continued)
Evaluation of Federal and State ARARs that Might Apply to OU-7,
Ellsworth Air Force Base, South Dakota
Standard Requirement, Criteria, or Limitation
Citation!
Description
A. Potentially Applicable or Relevant «nd Appropriate Federal Standard), Requirements, Criteria, and Limitations
ARAB Type
Applicability to OU-7
Resource Conservation and Recovery Act
Hazardous Waste Management System: General
Identification and Listing of Hazardous Wastes
Standards Applicable to Generators of Hazardous
Wastes
Standards Applicable to Transporters of Hazardous
Wastes
Standards for Owners and Operators of Hazardous
Waste TSDFs
Standards for Owners and Operators of Hazardous
Waste TSDFs with Interim Status
Tonic Substances Control Act (TSCA)
Fish and Wildlife Coordination Act
Endangered Species Act
Archaeological and Historic Preservation Act
Archaeological Resources Protection Act (1979)
40 CFR Part 260
40 CFR Part 261
40 CFR Part 262
40 CFR Part 263
40 Cm Part 264
40 CFR Part 265
40 CFR Part 761
16 USC 153 1 -666
40CFR6,302(g)
16 USC 1531-1543
50 CFR Parts 17. 402
40CFR6.302(g)
16 USC 469
40 CFR 6.301 (c)
93 Slat 721
16 USC 470
Establishes definitions, procedures, and criteria for modification or
revocation of any provision in 40 CFR Parts 260-265.
Defines those solid wastes that are subject to regulations as
hazardous wastes under 40 CFR Parts 262-265.
Establishes standards for generators of hazardous waste.
Establishes standards that apply to persons transporting hazardous
waste within the U.S. ifthe transportation requires a manifest under
40 CFR Part 262.
Establishes standards for acceptable hazardous waste management.
Establishes standards for acceptable hazardous waste management
during interim status.
Substances regulated under this rule include, but are not limited to,
soils and other materials contaminated as a result of spills.
Requires consultation when a federal department or agency proposes
or authorizes any modification of a stream or other water body and
adequate provision for protection of fish and wildlife resources.
Requires that federal agencies ensure that any action authorized,
funded, or carried out by the agency is not likely to jeopardize the
continued existence of any threatened or endangered species or
destroy or adversely modify critical habitat.
Establishes procedures to provide for preservation of historical and
archaeological data which might be destroyed through alteration of
terrain as a result of federal construction project for a federal
licensed activity or program.
Requires a permit for an excavation or removal of archaeological
resources from public or Indian land.
Action
Action
Action
Action
Action
Action
Action
Action
Location/Action
Location
Action/Location
Applicable for identifying hazardous waste during soil
removal, well placement, or trenching at OU-7.
Applicable for identifying hazardous waste during soil
removal, well placement, or trenching at OU-7.
Applicable to alternatives relating to removal or off-site
transport of a hazardous material.
Applicable for any transport of hazardous materials off site.
Relevant and appropriate for performance guidelines for
landfill closure.
Relevant and appropriate for performance guidelines for
landfill closure.
Applicable.
Not an ARAR.
Not an ARAR. Ecological Assessment did not identify OU-
7 as having critical habitat or endangered species.
Potential ARAR. OU-7 was used for landfilling activities.
No known historic or archaeological value, although no
confirmation study has been performed.
Not an ARAR.
lp\3107003^1 raft rod. doc
2-26
April 30. 1996
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Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South Dakota
Table 2-1 (continued)
Evaluation of Federal and State ARARs that Might Apply to OU-7,
Ellsworth Air Force Base, South Dakota
Standard Requirement, Criteria, or Limitation
A. Potentially Applicable or Relevant and Appro!
Executive Order on Floodplains Management
Executive Order on Protection of Wetlands
B. Potentially Applicable or Relevant and Appro
South Dakota Air Pollution Control Regulations
South Dakota Waste Management Regulations
South Dakota Waste Management Regulations
South Dakota Waste Management Regulations
South Dakota Waste Management Regulations
South Dakota Waste Management Regulations
South Dakota Water Discharge Permit Rules
South Dakota Water Discharge Permit Rules
South Dakota Water Discharge Permit Rules
South Dakota Water Quality Standards
South Dakota Remediation Criteria for Petroleum-
Contaminated Soils
South Dakota Ground Water Standards
Citations
Description
priale Federal Standards, Requirements, Criteria, and Limitations
Exec. Order No. 11.988
40CFR6.302(b)A
Appendix A
Exec. Order No. 11,990
40CFR6.302(a)A.
Appendix A
Requires federal agencies to evaluate the potential effects of actions
they may take in a flood plain to avoid, to the extent possible, the
adverse impacts associated with direct and indirect development of a
flood plain.
Requires federal agencies to avoid, to the extent possible, the
adverse impacts associated with the destruction or loss of wetlands
and to avoid support of new construction in wetlands if a practicable
alternative exists.
priale Stale Standards, Requirements, Criteria, and Limitations
74:26:01:09,24,25.26-28
74:26:03:04
74:27:03:11
74:27:09:06
74:27:15
74:28:24:01
74:03:18:01-17
74:03:19:01-08
74:03:01
74:03:04:02,10
74:03:32
74:03:15
Establishes permit requirements for construction, amendment, and
operation of air discharge services.
Establishes requirements for disposal of hazardous waste in sanitary
landfills.
Defines requirements for closure of solid waste disposal facilities.
Defines criteria for permit application for other solid waste TSD
facilities.
Establishes standards for landfill closure and post-closure
monitoring.
Establishes standard for transporters of waste.
Establishes surface-water discharge permit application requirements.
Establishes surface-water permit conditions.
Establishes requirements for individual and small on-site wastewater
systems.
Defines use of Boxelder Creek and certain tributaries.-
Establishes requirements for the remediation of soil contaminated
with petroleum products.
Defines ground- water classifications by beneficial use and sets
chemical standards.
ARAR Type
Location
Action/Location
Action
Action
Action
Action
Action
Action
Action
Action
Action
Action
Chemical
Chemical
Applicability to OU-7
Not an ARAR. Area not in 100-year flood plain.
Not an ARAR. OU-7 does not have identified wetland
areas.
Applicable.
Relevant and appropriate for landfill closure performance
guidelines.
Relevant and appropriate for landfill closure performance
guidelines.
Not an ARAR.
Relevant and appropriate.
Relevant and appropriate.
Applicable for any ground-water treatment discharge.
Applicable for any ground-water treatment discharge.
Applicable for any ground-water treatment plant.
Relevant and appropriate for any ground-water treatment
discharge to Boxelder Creek.
Relevant and appropriate for evaluating acceptable levels of
petroleum products in the soil.
Relevant and appropriate in evaluating the beneficial use of
impacted ground water.
lp\3l0700Mraflrod.doc
2-27
April 30. 1996
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Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South Dakota
3. LIST OF ACRONYMS AND ABBREVIATIONS
ACC: Air Combat Command
AF: Air Force
AFB: Air Force Base
ARARs: Applicable or Relevant and Appropriate Requirements
BTEX: Benzene, toluene, ethylbenzene, and xylene
CAMU: Corrective action management unit
CERCLA: Comprehensive Environmental Response, Compensation and Liability Act of
1980
COC: Contaminants of Concern
CRP: Community Relations Plan
EAFB: Ellsworth Air Force Base
EM: Electromagnetic
EPA: U.S. Environmental Protection Agency
FFA: Federal Facilities Agreement
FPTA: Fire Protection Training Area
FTA: Fire Training Area
GPR:. Ground Penetrating Radar
HI Hazard Index
HQ: Headquarters
IRIS: Integrated Risk Information System
IRP: Installation Restoration Program
LDR: Land disposal restriction
LLRWB: Low-Level Radioactive Waste Burial
MCL: Maximum Contaminant Level
MCLG: Maximum Contaminant Level Goal
p.g/kg Micrograms per kilogram
|0.g/L: Micrograms per liter
mg/kg Milligrams per kilogram
mg/L: Milligrams per liter
MSL: Mean Sea Level
tp\3107003Vraftrod.doc
3-1
April 30. 1996
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. Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South Dakota
NCP: National Oil and Hazardous Substances Contingency Plan
NEPA: National Environmental Policy Act
NPDES: National Pollutant Discharge Elimination System
NPDWR: National Primary Drinking Water Regulations
NPL: National Priorities List
OMTCS: Octamethyltetracyclosiloxane
OU: Operable Unit
O&M: Operation and maintenance
PAH: Polynuclear Aromatic Hydrocarbon
pCi/g Picocuries per gram
pCi/L: Picocuries per liter
PL: Public Law
ppm: Parts per million by weight
RA: Remedial action
RAB: Restoration Advisory Board
RAOs: Remedial action objectives
RCRA: Resource Conservation and Recovery Act of 1986
RI/FS: Remedial Investigation/Feasibility Study
ROD: Record of Decision
SARA: Superfund Amendments and Reauthorization Act
SDDENR: South Dakota Department of Environment and Natural Resources
SVOC: Semivolatile Organic Compound
TCE: Trichloroethylene
TCL: Target Compound List
TIC: Tentatively identified compound
UCL95 95 percent upper confidence limit
US AF: United States Air Force
UST: Underground storage tank
VOC: Volatile Organic Compound
WSA: Weapons Storage Area
tp\3107003\draftrod. doc
3-2
April 30, 1996
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Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South Dakota
APPENDIX A
FIGURES
tp\310700Mrafirod.doc A-l April 30, 1996
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-------
a
c
2:
<£
£E;
0.
22
UINKESOTA
HORW OWOTA
.
SOUTH DAKOTA
ELUSWOKIH AFB
BUCK ma
UPUT
ELLSWORTH AFB
Rapid Oty
Scale In Kile*
APPROXIMATE
ELLSWORTH
AIR FORCE BASE
ELLSWORTH AFB
RAPE OTY. soum MCOTA
AREA LOCATION MAP
PROJECT UGR
DESIGNED BY
DRAWN BY
MRG
CHECKED BY
SCALE
AS SHOWN
DATE
MAY 95
PROJECT NO
60378.85
FIGURE:
2-1
-------
o
I
32
~
DEBRIS
BURIAL
AREA
N
OU-1
OU-2
OU-3
OU-4
OU-5
OU-6
OU-7
ou-a
OU-9
OU-10
OU-1t
OU-12
1200 2«00
SCALE U FEET
LEGEND
OPERABLE UNITS
FIRE PROTECTION TRAINING
AREA (FT-01)
LANDFILLS 1 tc. 6 (LF-02)
LANDFILL 2 - - - -
LANDFILL 3
LANDFILL 4
LANDFILL 5
OU-2
(LF-03)
(LF-O4)
(LF-05)
(LF-06)
LOW LEVEL RADIATION WASTE BURIAL AREA (RW-07)
EXPLOSIVE OROANCE DISPOSAL AREA & PRAMITOL SPILL
OLD AUTO HOBBY SHOP AREA (OT-15)
NORTH HANGAR COMPLEX (ST-19)
BASEWIDE GROUND WATER
HARDna NO. 1
ELLSWORTH
AIR FORCE BASE
ELLSWORTH AFB
RAPID OTY. SOUTH DAKOTA
SITE LOCATION MAP
PROJECT MGR
OCSKMED BT
ORWH er
STAFF
CHECKED BT
SCALE
AS SHOWN
DATE
OCT 94
PROJECT NO
60378.86
FIGURE:
2-2
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Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South Dakota
APPENDIX B
RESPONSIVENESS SUMMARY
tp\310700Mrafirod.doc April 30. 1996
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Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South Dakota
Responsiveness Summary
Remedial Action at Operable Unit Seven
Ellsworth Air Force Base, South Dakota
1. Overview
The United States Air Force (USAF) established a public comment period from December 28,
1995 to January 27, 1996 for interested parties to review and comment on remedial alternatives
considered and described in the Proposed Plan for Operable Unit 7 (OU-7). The Proposed Plan
was prepared by the USAF in cooperation with the U.S. Environmental Protection Agency
(USEPA) and the South Dakota Department of Environment and Natural Resources (SDDENR).
The USAF also held a public meeting at 6:30 p.m. on January 11, 1996 at the Douglas Middle
School to outline the proposed remedy to reduce risk and control potential hazards at the
Operable Unit (OU).
The Responsiveness Summary provides a summary of comments and questions received from.the
community at the public meeting and during the public comment period as well as the USAF's
responses to public comments.
The Responsiveness Summary is organized into the following sections:
Background on Community Involvement
Summary of Comments and Questions Received During the Public Comment Period and
USAF Responses
Remaining Concerns
2. Background on Community Involvement
On August 30, 1990 Ellsworth Air Force Base (EAFB) was listed on the USEPA's National
Priorities List (NLP). A Federal Facilities Agreement (FFA) was signed in January 1992 by Air
Force, USEPA, and the State and went into effect on April 1, 1992. The FFA establishes a
procedural framework and schedule for developing, implementing, and monitoring appropriate
response actions for EAFB.
Community relations activities that have taken place at EAFB to date include:
FFA process. After preparation of the FFA by the USAF, USEPA, and SDDENR, the
document was published for comment. The FFA became effective April 1, 1992.
tp\3107003\rcspsum.doc B-l April 30,1996
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Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South Dakota
Administrative Record. An Administrative Record for information was established in
Building 8203 at EAFB.' The Administrative Record contains information used to support
USAF decision-making. All the documents in the Administrative Record are available to the
public.
Information repositories. An Administrative Record outline in located at the Rapid City
Library (public repository).
Community Relations Plan (CRP). The CRP was prepared and has been accepted by EPA
and the State of South Dakota and is currently being carried out. An update to this plan will
be prepared in 1996.
Restoration Advisory Board (RAB). The RAB has been formed to facilitate public input in
the cleanup and meets quarterly. In addition to USAF, EPA, and South Dakota oversight
personnel, the RAB includes community leaders and local representatives from the
surrounding area.
Mailing list. A mailing list of all interested parties in the community is maintained by EAFB
and updated regularly.
Fact sheet. A fact sheet describing the status of the IRP at EAFB was distributed to the
mailing list addressees in 1992.
Open house. An informational meeting on the status of the IRP and other environmental
efforts at EAFB was held on May 6, 1993. An open house was held November 16, 1995 in
conjunction with the Restoration Advisory Board meeting. Information on the status of
environmental efforts at EAFB was provided.
Newspaper articles. Articles have been written for the base newspaper regarding IRP
activity.
The Proposed Plan for this remedial action was distributed to the mailing list addressees for their
comments and additional copies of the Proposed Plan were -available at the January 11, 1996
public meeting. A transcript of comments, questions and responses provided during the public
meeting was prepared.
3. Summary of Comments and Questions Received During the Public Comment Period
and USAF Responses
Part I - Summary and Responses to Local Community Concerns
Review of the written transcript of the public meeting did not indicate community objections to
the proposed remedial action. No written comments were received during the public comment
period.
tp\3107003\respsum.doc B-2 April 30,1996
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Final Record of Decision Operable Unit 7
Ellsworth Air Force Base, South. Dakota
Part n - Comprehensive Responses to Specific Technical, Legal
_ and Miscellaneous Questions
The comments and questions below have been numbered in the order they appear in the written
transcript of the January 11, 1996 public meeting.
Comment 1. Jan Deming
Asked if this area will still be used during the cleanup process when USAF is
removing soils and if that is going to be a hazard.
Response 1.
USAF will not be removing soils from the Weapons Storage Area as part of the
recommended remedial alternative. The selected alternative only includes
institutional controls for soils. Therefore, this question is not applicable to the
selected remedial alternative.
Comment 2. JohnLuxem
Asked if USAF is going to take any soil out of the Weapons Storage Area.
Response 2.
See response to comment 1 above.
Comment 3. Phyllis Engleman
Asked if any contaminants will be in the treated effluent from the sanitary
wastewater treatment plant.
Response 3.
The selected remedial alternative for ground water does not include recovery of
potentially contaminated ground water and treatment at the on-Base sanitary
wastewater treatment plant. It only includes institutional controls for ground
water. Therefore, this question is not applicable to the selected remedial
alternative.
tp\3107003\respsum.doc B-3 April 30, 1996
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ELLSWORTH AFB
Rapid City. South Dakot
-------
Existing Controlled Access
Fence
MW93B603
(Existing Upgradient
Monitoring Well).
TANK UST
(TK02)
TANK UST
(TK01)
SUSPECTED
WASTE DISPOSAL
TRENCH
SURFACE-WA
POND
inniiniiniinunnniini
TANK UST
(TK05)
Jl X
NEW SUSPECTED LOCATION
THAT WAS NOT SURVEYED
~\
Existing
Controlled Access
Alternatives 2 and 5
Institutional Controls for Soil and Ground Water
OU 7 (LLRWB)
ELLSWORTH AFB
Rapid City. South DakoU
-------
§
MION
EN/
OIL
ABOVE
\L= 10'
APPROXIMAT
EXTENT OF OU-8 DEBRIS
BURIAL STUDY AREA
(AREA 2)
cr <
oo
EUUSWORTM
AIR FORCE BASE
ELLSWORTH AFB
SOUTH OWCOM
DEBRIS BURIAL AREA
ALTERNATIVE NO. 3
SOIL REMOVAL VEGETATIVE COVER/
INSTITUTIONAL CONTROLS
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