PB96-964407
EPA/ROD/R08-96/119
October 1996
EPA Superfund
Record of Decision:
Ellsworth Air Force Base,
Operable Unit 2, Rapid City, SD
5/10/1996
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Final
Record of Decision for
Remedial Action at Operable Unit 2
Ellsworth Air Force Base, South Dakota
United States Air Force
Air Combat Command
Ellsworth Air Force Base
April 1996
Air Force Project No. FXBM #947002
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base, South Dakota
TABLE OF CONTENTS
Chapter - Page
1.0 DECLARATION-FOR THE RECORD OF DECISION 1-1
1.1 SITE NAME AND LOCATION 1-1
1.2 STATEMENT OF BASIS AND PURPOSE 1-1
1.3 ASSESSMENT OF THE SITE 1-1
1.4 DESCRIPTION OF SELECTED REMEDY 1-1
1.5 STATUTORY DETERMINATION 1-2
1.6 SIGNATURE AND AGENCY CONCURRENCE ON THE REMEDY 1-2
2.0 DECISION SUMMARY 2-1
2.1 SITE NAME AND LOCATION 2-1
2.2 OU-2 DESCRIPTION/HISTORY AND REGULATORY OVERSIGHT ACTIVITIES 2-1
2.2.1 Description/History 2-1
2.2.2 Regulatory Oversight Activities 2-2
2.3 HIGHLIGHTS OF COMMUNITY PARTICIPATION 2-3
2.4 SCOPE AND ROLE OF RESPONSE ACTION 2-4
2.5 SITE CHARACTERISTICS 2-5
2.5.1 Soils : 2-5
2.5.2 Sediment 2-6
2.5.3 Ground Water 2-7
2.5.4 Surface Water 2-8
2.6 SITE RISK SUMMARY 2-8
2.6.1 Human Health Risks 2-8
2.6.2 Ecological Risks 2-11
2.7 DESCRIPTION OF ALTERNATIVES.:! 2-11
2.8 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 2-13
2.8.1 Overall Protection of Human Health and the Environment 2-14
2.8.2 Compliance with ARARs 2-14
2.8.3 Long-Term Effectiveness and Permanence 2-16
2.8.4 Reduction of Toxicity, Mobility, and Volume Through Treatment 2-17
2.8.5 Short-Term Effectiveness 2-17
2.8.6 Implementability 2-17
2.8.7 Cost 2-18
2.8.8 State Acceptance 2-20
2.8.9 Community Acceptance 2-20
2.9 SELECTED ALTERNATIVE ...2-20
2.10.1 Protection of Human Health and the Environment 2-24
2.10.2 Compliance with ARARs 2-25
2.10.3 Cost Effectiveness 2-25
2.10.4 Utilization of Permanent Solutions and Alternative Treatment Technologies to the
Extent Possible 2-25
. 2.10.5 Preference for Treatment as a Principal Element 2-26
2.11 DOCUMENTATION OF SIGNIFICANT CHANGES 2-26
3.0 LIST OF ACRONYMS AND ABBREVIATIONS 3-1
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base, South Dakota
APPENDICES
Appendix A Figures
Appendix B Responsiveness Summary
LIST OF FIGURES
Figure 2-1 Area Location Map
Figure 2-2 Site Map
Figure 2-3 Operable Unit 2 - Location of Landfill Nos. 1 and 6
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base, South Dakota
1.0 DECLARATION FOR THE RECORD OF DECISION (ROD)
1.1 SITE NAME AND LOCATION
• Operable Unit 2 (OU-2), Landfill Nos. 1 and 6, Ellsworth Air Force Base (EAFB),
National Priorities List (NPL) Site.
• Meade and Pennington Counties, South Dakota.
1.2 STATEMENT OF BASIS AND PURPOSE
This decision document describes EAFB's selected remedial action for OU-2, 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-2, EAFB. The US
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-2, 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 contaminated areas, or operable units (OUs), have been identified at EAFB. This ROD is
for a remedial action at OU-2 and is the 5th ROD for EAFB.
For Landfill No. 1, the selected alternative, an earth cover and institutional controls, includes the
following major components:
• Constructing an earth cover, capable of sustaining perennial vegetation, over those areas
of the landfill that are not adequately covered. Filling in low areas and grading the entire
landfill area to provide for positive drainage off the site;
» Institutional controls for the landfill area;
• Long-term ground-water monitoring; and,
• Long-term maintenance of soil cover.
• Realignment and lining of the storm-water channel.
For Landfill No. 6, the selected alternative, institutional controls, includes the following major
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components:
• Institutional controls for the landfill area; . ••_ •-. .
• Long-term ground-water monitoring; and,
• Long-term maintenance of existing cover.
1.5 STATUTORY DETERMINATION
The selected remedies are protective of human health and the environment, complies with Federal
and the 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 and
alternative treatment (or resource recovery) technologies, to the maximum extent practicable for
OU-2. However, because treatment of the principal threats of the OU was not found to be
practicable, this remedy does not satisfy the statutory preference for treatment as a principal
element. The size of the landfills and the fact that there are no apparent on-site hot spots that
represent major sources of contamination preclude a remedy in wiiich contaminants could be
excavated and treated effectively.
Because this remedy will result in low levels of hazardous or potentially hazardous substances
remaining onsite beneath the landfill covers, a review will be conducted no less 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. If the results of the review indicate that
conditions at OU-2 have changed, the remedies may be modified to reflect any changes.
1.6 SIGNATURE AND AGENCY CONCURRENCE ON THE REMEDY
\ /",
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BRETT M. DULA Date
Lieutenant General, USAF
Vice Commander
JACK W. MCGRAW Date
Acting Regional Administrator
US Environmental Protection Agency Region 8
NETTIE H. MYERS, Secretary Date
Department of Environment and Natural Resources
State of South Dakota
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For Landfill No. 6, the selected alternative, institutional controls, includes the following major
components:
• Institutional controls for the landfill area;
• Long-term ground-water monitoring; and,
• Long-term maintenance of existing cover.
1.5 STATUTORY DETERMINATION
The selected remedies are protective of human health and the environment, complies with
Federal and the 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 and alternative treatment (or resource recovery) technologies, to the maximum extent
practicable for OU-2. However, because treatment of the principal threats of the OU was not
found to be practicable, this remedy does not satisfy the statutory preference for treatment as a
principal element. The size of the landfills and the fact that there are no apparent on-site hot
spots that represent major sources of contamination preclude a remedy in which contaminants
could be excavated and treated effectively.
Because this remedy will result in low levels of hazardous or potentially hazardous substances
remaining onsite beneath the landfill covers, a review will be conducted no less 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. If the results of the review indicate that
conditions at OU-2 have changed, the remedies may be modified to reflect any changes.
1.6 SIGNATURE AND AGENCY CONCURRENCE ON THE REMEDY
BRETT M. DULA Date
Lieutenant General, USAF
Vice Commander
C
MCK W. MCGRAW Date
i^ctirigTlegional Adminrsaator
US Environmental Protection Agency Region 8
NETTIE H. MYERS, Secretary Date
Department of Enviroi^men/ and Natural Resources
State of South Dakota
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base, South Dakota
2.0 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, and 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 OU-2 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 at EAFB. Presently, the 28th Bombardment Wing (B-1B
bombers) is the host unit of EAFB.
The operable unit 2 (OU-2) study area consists of Landfill No. 1, Landfill No. 6, the drainage
channel in the western portion of Landfill No. 1, and the drainage channel near Landfill No. 6,
which includes Pond 002.
Landfill No. 1 is approximately 21.5 acres in size and is located at the southern boundary of
EAFB (Figure 2-3). The landfill was active from the early 1940s to 1964 and was used to dispose
of a variety of wastes including Base refuse, incinerator ash, sludge, oil, and possibly liquid
industrial wastes. Hardfill debris was also disposed of at Landfill No. 1.
Aerial photo analysis conducted by the EPA from historical photos (1938 to 1990) indicated the
types of disposal practices at Landfill No. 1. Through interpretation of these photographs, landfill
materials appear to have been placed in trenches in the eastern two-thirds of the landfill (Figure 2-
3). The western third of the landfill appears to have been used to dispose of primarily hardfill
materials. This is evidenced by the presence of exposed rubble piles in this area. Hardfill has been
placed along the embankment of the drainage channel in the western portion of the landfill. Other
disposal practices at Landfill No. 1 include open burning of refuse and debris.
In general, the surface topography of Landfill No. 1 slopes in a southeasterly direction from
Kenney Road to the southern Base boundary. An intermittent storm-water channel flows adjacent
to and through the western portion of the landfill area. The storm water flowing through the
channel originates from areas upstream of OU-2.
Landfill No. 6 is approximately 0.5 acre in size and is located northeast of Landfill No. 1 on the
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north side of Kenney Road (Figure 2-3). Landfill No. 6 was used from 1962 to 1965 and
primarily received general Base refuse. Waste oil, fuel, and solvents may also have been disposed
of at this location. However, no direct physical evidence of these chemicals was found at Landfill
No. 6 during the 1993/1994 remedial investigation (RI) field activities.
Landfill No. 6 is situated on an eastward sloping hillside just west of a small pond designated as
Pond 002. Surface drainage from Landfill No. 6 flows eastward toward Pond 002. In addition to
runoff from the landfill, Pond 002 receives runoff from the western one-half of the runway and
adjacent areas, and from storm water drains located on the alert apron. Outflow from Pond 002
empties into a small ephemeral stream that flows to the south.
A shallow aquifer has been identified at depths of 10 to 50 ft beneath the ground surface at
various areas of the Base. At OU-2, shallow ground water was found at depths ranging from 10
to 25 ft at Landfill No. 1, and 15 to 20 ft at Landfill No. 6. In general, the shallow ground water
at EAFB is classified as having a beneficial use as a drinking water supply suitable for human
consumption (ARSD Chapter 74:03:15, Groundwater Quality Standards), but is not currently
being used. The shallow aquifer may also discharge to the surface.
Deeper bedrock aquifers also exist beneath EAFB. These deeper aquifers are separated from the
shallow aquifer by 800 feet of low-permeability 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.
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 NPL. A
Federal Facilities Agreement (FFA) was signed in January 1992 by the Air Force, 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 Air Force compliance with
the specific requirements. The FFA identified 11 site-specific operable units (OUs) and a Base-
wide ground-water OU. The Base-wide ground-water OU is primarily used to address
contaminated ground water that was not addressed during an investigation of a site-specific OU.
Listing on the NPL and execution of the FFA required the U.S. Air Force to perform a remedial
investigation/feasibility study (PJ/FS) to investigate the 12 operable units. In 1993 and 1994, an
extensive RI field program was conducted to characterize conditions at OU-2. The program
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included drilling and sampling of boreholes, installation of monitoring wells, ground-water
sampling, geotechnical analysis of soil samples, ecological evaluation, 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 implemented. 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 State
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 at the open
house.
• 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
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addressees for their comments.
A public comment period was held from September 18 to October 18, 1995, and a public meeting
was held on September 26, 1995. 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-2, in accordance with
the CERCLA, as amended by SARA, and the NCP. The RI/FS reports and the Proposed Plan for
OU-2 provide information about OU-2 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 site-specific OUs and a Base-wide ground-water OU. 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 Hardfill No. 1
This ROD documents the selected remedial action (RA) at OU-2 and is the 5th ROD for EAFB.
The remedial action objectives (RAOs) are to reduce the potential risks posed by contaminants in
surface soils and to reduce the mobility of potential contaminants in the landfills through
containment.
The development of alternatives for the landfills was conducted under EPA's Presumptive
Remedies Approach /Presumptive Remedies: Policy and Procedures (OSWER Directive 9355.0-
47FS); Presumptive Remedy for CERCLA Municipal Landfill Sites (OSWER Directive 9355.0-
49FS,)/. In using this approach, selecting an alternative for remediation is streamlined by using
preferred technologies based on historical patterns of remedy selection and EPA's scientific and
engineering evaluation of performance data on technology implementation.
The presumptive remedy stipulates containment as the appropriate remedy for landfills. The
response action, containment by covering, would reduce risk associated with the ingestion, dermal
contact, and inhalation exposure pathways. The area over which remediation goals will be
achieved after remediation is complete is defined as the area of attainment, and is based on the
RAOs. For OU-2, the area of attainment consists of the identified boundaries of Landfills No. 1
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and 6. This includes the areas of the landfills not meeting appropriate State of South Dakota
closure standards. The remedial investigation determined that Landfill No. 6 presently meets the
appropriate closure.standards. Measures to address leachate or gas collection were not
considered since identified wastes placed in the landfills are not likely to produce significant
amounts of gas, nor does the waste typify that which would normally be associated with
significant leachate production. Further, analytical results indicate that chemicals detected in the
ground water beneath Landfill No. 1 have not moved beyond the boundaries of the landfill in the
30 years since it has been used.
2.5 SITE CHARACTERISTICS
This section describes the presence and distribution of contaminants at OU-2 as a result of past
activities.
2.5.1 Soils
Volatile Organic Compounds (VOCs)
Low concentrations of VOCs were detected in surface and subsurface soil samples collected at
Landfill No. 1, the majority of which were detected in subsurface samples. The most common
VOCs detected were benzene, toluene, ethylbenzene, xylene (BTEX), and acetone.
Trichloroethene (TCE) and dichloroethene (DCE) were also detected. The highest reported
values for these compounds were found in samples collected from suspected trench locations and
are believed to be the result of past disposal activities at OU-2. There were no VOCs in soil
samples collected from Landfill No. 6. VOCs were evaluated in the risk assessment for Landfill
No. 1.
Semivolatile Organic Compounds (SVOCs)
Several SVOCs were detected in surface and subsurface soil samples collected at OU-2, mostly at
Landfill No. 1. The most frequently reported SVOCs in soils were polynuclear aromatic
hydrocarbons (PAHs). The most frequently reported PAH in surface soil samples at OU-2 was
benzo(a)anthracene. Naphthalene, 2-methylnaphthalene, P-cresol, and chrysene were the most
frequently reported PAHs in subsurface soils. No specific pattern of PAH contamination exists in
the surface or subsurface soil. PAHs are commonly found in the environment at industrial sites.
The PAHs detected in surface soils are likely associated with overall Base-wide activities rather
than past disposal at the landfills. The subsurface soil contamination may be associated with
disposal of certain items such as waste oil or asphalt material. Because of uncertainties associated
with characterizing the contents of landfills, the PAHs were evaluated in the risk assessment.
Total Petroleum Hydrocarbons (TPH)
Total petroleum hydrocarbon, as jet fuel, was detected in one surface and one subsurface sample
collected at Landfill No. 1. TPH was not detected in soils at Landfill No. 6. The concentration of
TPH in the surface soil sample was above the State action level for petroleum contaminated soils.
TPH was also detected in samples collected from beyond (south of) the Base boundary. This
TPH is related to a leak in the fuel line located along the southern boundary of OU-2 and not
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related to past disposal activities at OU-2. This fuel contamination is being addressed separately
by the Air Force and the remediation is not included as part of OU-2.
Pesticides
Low concentrations of pesticides were reported in several surface and subsurface soil samples at
Landfill No. 1 and one surface sample at Landfill No. 6. The pesticides in surface soil samples are
likely from past pesticide application practices at EAFB, not from disposal in the landfills.
Pesticides detected in the subsurface may be from pest-management activities or disposal
activities. Large-scale disposal of pesticides in OU-2 landfills is not suspected. Supporting this
conclusion is that the ground water beneath Landfill No. 1 contained only low concentrations of
pesticides. There were no pesticides detected in ground water at Landfill No. 6. Pesticides were
included in the evaluation during the risk assessment.
Inorganic Contaminants
The concentrations of several inorganic compounds in the soil samples exist at levels above
background concentrations. This is believed to be due to a combination of landfill activities and
variations in the concentrations of naturally-occurring compounds in the soil. No specific pattern
of inorganic contamination exists in the soil. The risk assessment indicated that no unacceptable
risk exists for these inorganic compounds in soils.
2.5.2 Sediment
Organic Contaminants
Organic contaminants reported in sediment samples included SVOCs and pesticides. The most
commonly reported SVOCs in sediment were PAHs including naphthalenes, pyrenes, anthracenes,
and fluoranthenes. Pesticides were reported in samples collected from both the east and west
drainages. Reported pesticides are considered to be a result of historical Base-wide pest
management practices and are not considered to be a result of past disposal at OU-2.
Sample results from certain locations indicate that the contaminants detected in sediment
originated from surface water runoff from other areas of EAFB and cannot be specifically linked
to landfill activities. However, these contaminants were evaluated in the risk assessment.
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Inorganic Contaminants
Inorganic compounds were detected in the sediment samples from the drainage channels.
Inorganic compounds are within the range of naturally-occurring concentrations and are believed
to be the result of natural variations in geologic deposits. However, due to the uncertainties in
determining the contents of landfills, the inorganic compounds were also evaluated in the risk
assessment.
2.5.3 Ground Water
Ground-water sample results indicate that ground-water contamination at OU-2 is confined within
the limits of Landfill No. 1. Analytical data indicate that contaminants in the ground water
beneath OU-2 have not moved beyond the boundaries of the landfill in the 30 years since it ceased
operation. Ground-water contamination off-Base (to the south) is related to a fuel line rupture
that occurred in 1989 and is not related to landfill activities. Remediation of off-Base fuel
contamination is being addressed through State of South Dakota petroleum release regulations
(ARSD Chapter 74:03:33).
VOCs
Several VOCs were detected in ground-water samples collected at OU-2. The most notable
VOCs detected in samples collected within Landfill No. 1 include benzene, total BTEX, TCE, and
DCE. TCE and DCE were detected above Maximum Contaminant Levels (MCLs). These VOCs
are believed to be the result of past waste-disposal activities at Landfill No. 1. Landfill No. 1
ceased operation in 1964, and chemicals detected beneath the landfill have not moved beyond its
boundaries in the 30 years since it has been used. There were no VOCs detected in ground-water
samples at Landfill No. 6. VOCs in the ground water were evaluated in the risk assessment.
Other Organic Contaminants
Other organic contaminants detected in ground-water samples collected at OU-2 include low
concentrations of S VOCs (only two) and pesticides. The exact source of pesticides is not known.
Historical use of pesticides at the Base has been documented and it is believed that pesticides
detected in sediment at OU-2 are the result of past pest management activities. There are no
known records of disposal of pesticide products in the OU-2 landfills. These compounds were
included in the evaluation during the risk assessment.
inorganic Contaminants
Inorganic compounds were detected in ground-water samples, at concentrations exceeding
background. Also, five inorganic compounds (cadmium, nickel, lead, antimony, and selenium)
were detected above MCLs. The source of the high concentration inorganic compounds at OU-2
is not known. Samples collected upgradient and sidegradient of Landfill No. 1 also contained
high concentrations of inorganic compounds indicating that the source of these compounds is not
related to activities at the landfills. The distribution of inorganic compounds detected in OU-2
samples indicates that the high concentrations are the result of natural variations in geologic
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deposits. However, because of uncertainties associated in determining landfill characteristics,
inorganic compounds were-evaluated in the risk assessment.
2.5.4 Surface Water
Organic Contaminants
Surface water samples were taken from the surface water bodies at OU-2. Several organic
contaminants were detected in surface water samples taken from the drainage channel in the
western portion of Landfill No. 1, and upstream and downstream of Pond 002. There were no
VOCs or pesticides detected in the surface water samples. Only low concentrations of three
SVOCs were detected in surface water samples at OU-2.
Inorganic Contaminants
Many inorganic compounds were detected in the surface water samples. The concentrations of
several of these compounds (arsenic, iron, manganese, nickel, and selenium) were detected at
concentrations that exceeded Federal Ambient Water Quality Criteria (FAWQC) and State Water
Quality Standards. The highest frequency of compounds reported above FAWQC was in samples
collected upgradient of OU-2, which indicates that they are not related to activities at the landfills.
Inorganic compounds were evaluated in.the risk assessment.
2.6 SITE RISK SUMMARY
2.6.1 Human Health Risks
Risk Assessment Process
The assessment of human health risks for this OU considered the following topics:
(1) Chemicals of concern (COCs) in ground-water, surface water, sediment, and soil
samples taken at OU-2;
(2) Current and future land-use conditions;
(3) Potential environmental pathways by which populations might be exposed;
•(4) Estimated exposure point concentrations of COCs;
(5) Estimated intake levels of the COCs;
(6) Toxicity of the COCs; and
(7) Uncertainties in the assessments of exposure, toxicity, and general risks.
Noncarcinogenic and carcinogenic risks were calculated for the following five potential exposure
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groups at OU-2:
(1) Current EAFB maintenance personnel who ingest or have dermal contact with surface
soil while mowing grass onsite;
(2) The future adult living onsite who ingests or has dermal contact with surface soil, or
ingests or showers with ground water;
(3) Future adolescents living onsite who are exposed to surface water and sediment through
wading; and
(5) Future adult construction workers who perform excavation activities.
A quantitative risk assessment was performed for the ground water, surface water, soil, sediment,
and air. The risk assessment evaluated potential effects on human health posed by exposure to
contaminants within OU-2. 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 incidence in ten
thousand people to one cancer incident in one 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 upon 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 excess (i.e., over background) cancer risks due to exposure from
contaminants.
Noncarcinogenic health risks are evaluated using a hazard index (HI). If the hazard index is less
than or equal to one, the contaminant concentration is considered an acceptable level and
generally assumes that the human population may be exposed to it during a 30-year period
without adverse health effects.
Risk Assessment Results
The risk assessment for OU-2 indicated that the carcinogenic risk slightly exceeded the acceptable
range only from ingestion of ground water containing arsenic and beryllium. Arsenic and
beryllium are considered naturally occurring at OU-2. All other quantified carcinogenic risks
were within the acceptable risk range.
Part-of the remaining site risk includes risks from exposure to surface soil contaminants. The
chemicals which contributed the majority of risk in the soil were PAHs. Benzo(a)pyrene, a PAH,
is the primary contaminant identified in the risk assessment as contributing to risk from soils.
However, only one surface soil and two subsurface soil samples actually contained concentrations
of benzo(a)pyrene that are of concern. Due to the heterogeneity of the landfill contents,
uncertainty is associated with the calculated risk values for the surface soil.
Benzo(a)pyrene was also the primary chemical contributing to carcinogenic risk in the sediments
at OU-2. Five of seven sediment samples contained benzo(a)pyrene at concentrations that are of
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concern. However, the results of the risk assessment indicate that risk due to exposure to
contaminants in sediments at OU-2 is within the acceptable risk range. It is typical for
compounds in the surface soil to wash into adjacent drainages and to settle or become trapped in
the drainage areas. -Remedial action for the drainage areas outside of the landfill boundaries is not
warranted.
The risk assessment for OU-2 indicated that the only noncarcinogenic risk resulting in an HI
above 1.0 was from ingestion of ground water containing arsenic. Arsenic detected in samples
throughout the Base is considered to be naturally occurring.
Results of the risk assessment indicated that surface water was not a media of current concern.
Chemicals detected in the ground water which contributed to excess risk are considered to be
naturally occurring. Therefore, remedial action is not warranted for the ground water and surface
water at this time.
Risk Summary
Remedial action is warranted for the landfills based on the potential risk to human health from
future releases of hazardous substances from the landfills. Contaminants in the landfills may leach
downward to contaminate the underlying ground water. Off-Base residents may then ingest or
come in contact with the contaminated ground water. Also, the surface of the landfills may erode,
thus exposing off-Base resident to contaminants in both surface water and air.
Due to the potential heterogeneity of the waste materials present within the landfills, a complete
characterization of waste materials present was not possible during the RI. This adds a degree of
uncertainty to the risk assessment for the landfill contents. Rather than attempting to fully
characterize landfill contents and gain more certainty in the risk assessment for the landfill
contents, the Air Force utilized guidance developed by EPA titled Presumptive Remedy for
CERCLA Municipal Landfill Sites (OSWER Directive 9355.0-49FS). The presumptive remedy
for landfills is onsite containment of landfill contents. Using the presumptive remedy strategy, a
quantitative risk assessment is not necessary to evaluate whether the containment remedy
addresses all exposure pathways and contaminants potentially associated with a landfill. Rather,
all potential exposure pathways can be identified using the conceptual site model and compared to
the pathways addressed by the presumptive remedy. Containment of the landfill contents
addresses exposure pathways and risks normally associated with landfills. The contaminant
exposure pathways for the potential risks at OU-2 include (1) direct physical contact with the
landfill contents, (2) consumption or contact with ground water that is or may become
contaminated, (3) consumption or contact with potentially contaminated surface water, and (4)
ingestion of potentially contaminated sediment in the drainages adjacent to and downgradient of
the landfills.
Actual or threatened releases of hazardous substances from OU-2, 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, and the environment.
2.6.2 Ecological Risks
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An ecological risk evaluation of OU-2 was based on a combination of data and literature reviews,
field and laboratory analyses, analyte evaluation and screening, and preliminary risk screening.
The pertinent findings are summarized below.
A variety of animal species may live, forage, or nest in OU-2 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-2, 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-2 area ensures unacceptable
risk to a single individual will not occur.
Findings of the RI indicate that the contaminants at OU-2 are not altering the ecology to
unacceptable levels. A Base-wide ecological risk assessment will be conducted as part of OU-11,
and OU-2 will be included in this Base-wide evaluation.
2.7 DESCRIPTION OF ALTERNATIVES
Presumptive Remedy for CERCLA Municipal Landfill Sites, (OSWER Directive 9355.3-11FS)
was the basis for the focused feasibility study (FS). The OSWER directive established
containment of the contamination within landfills and the collection and treatment of landfill gas
within the landfill boundary (if applicable) as the presumptive remedy for CERCLA municipal
landfills.
Although not specifically identified as municipal landfills, Landfill Nos. 1 and 6 at OU-2 exhibit
characteristics that make this presumptive remedy applicable. The landfills' contents at OU-2 do
not have the characteristics to produce significant quantities of leachate or gases. The ground
water contained concentrations of VOCs above MCLs, but these chemicals were only detected
within the boundaries of Landfill No. 1. Since ground-water fluctuations over time have not
caused transport of the contaminants beyond the landfill boundary, the primary threat to cause
chemical transport is future infiltration of precipitation through the landfill contents into the
ground water. Also, at Landfill No. 1, the drainage channel running through the western portion
of the landfill could potentially erode into the landfill and transport contaminants downstream.
Ground water is not a pathway of concern at Landfill No. 6. The heterogeneity of the landfill
contents causes uncertainties in the risk assessment. Although the use of the presumptive remedy
focuses on containment of landfill contents, it will also serve to reduce the potential for infiltration
of precipitation into a landfill.
Since Landfill No. 1 and Landfill No. 6 are distinct areas, alternatives were developed separately
for each landfill; however, a similar approach (the presumptive remedy) was used to develop
alternatives for each landfill and the list of potential alternatives was the same for both landfills
(with the knowledge that additional consideration may be required for Landfill No. 1 because of
the storm-water channel). Alternatives for Landfill No. 1 and Landfill No. 6 are summarized
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below. Since the identified risks at Landfill No. 6 are within the acceptable risk range and the
existing cover complies with the State of South Dakota standards, only Alternatives 1 and 2 were
considered for this landfill. Alternative 3 applies to Landfill No. 1 only.
Alternative I - No Action
• No Action.
• The no action alternative represents the baseline condition at OU-2 and refers to
taking no further action at OU-2. It is expected that existing maintenance (e.g.,
grass mowing) would be continued.
The no action alternative does not meet remedial action objectives for OU-2
Alternative 2 - Institutional Controls
• Implementing access restrictions.
• Restricting future land and ground-water use.
• Developing a long-term monitoring and maintenance plan for the landfill.
This alternative does not meet the remedial action objectives for Landfill No. 1; however, because
of the present condition of Landfill No. 6, Alternative 2 would meet the remedial action objectives
for Landfill No. 6.
Alternative 3 - Earth Cover/Institutional Controls (Landfill No. 1 only)
For Landfill No. 1, major components of Alternative 3 are:
• Implementing access restrictions.
• Restricting land and ground-water use.
• Realignment and lining of the storm-water channel.
• Developing a long-term monitoring and maintenance plan for the landfill.
• Installing an earth cover over the areas of the landfill that are currently not
adequately covered (approximately 2-3 acres of rubble). Filling low areas and
grading the entire area of the landfill to provide positive drainage off the area.
Alternative 3 meets the remedial action objectives for Landfill No. 1. The access restrictions,
institutional controls, and the long-term monitoring and maintenance would be the same as
described in Alternative 2.
2.8 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
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The analysis of alternatives coupled with the use of the presumptive remedy combine for a
narrower range of feasible approaches to address remedial activities at OU-2. Remedial Action
Objectives (RAOs) were established for OU-2 to minimize the exposure potential and risk
associated with the landfills. In meeting these RAOs, the alternatives must also comply with State
and Federal ARARs. Specifically, remedial actions must meet State of South Dakota Waste
Management Regulations for the disposal of solid waste (ARSD Chapter 74:27:15), Federal MCL
levels for contaminants in ground water, and other ARARs discussed in Section 2.8.2.
The RAOs for OU-2 are as follows:
• Provide protection against direct contact with contents of the landfills.
• Provide protection against ingestion of contaminated ground water at
concentrations exceeding regulatory or risk-based goals.
• Minimize the potential for transport of contaminants in the soils and ground water
beyond the boundaries of the landfills.
There are three general areas of concern for OU-2: Landfill No. 1, Landfill No. 6, and the surface
water bodies. The levels of chemicals in the surface water bodies at OU-2 do not warrant
remediation. The area of attainment is defined as the area which will achieve the remedial action
objectives after remediation is completed. The area of attainment for OU-2 is the extent of
Landfill No. 1, which is approximately 21.5 acres in size and Landfill No. 6, which is
approximately 0.5 acres in size (Figure 2-3).
Pursuant to Section 40 CFR 300.430(e)(9)(iii), the remedial action to be implemented should be
selected based upon consideration of nine evaluation criteria. These criteria are as follows:
1. Overall protection of human health and environment.
2. Compliance with applicable or relevant and appropriate requirements (ARARs).
3. Long-term effectiveness and permanence.
4. Reduction of toxicity, mobility, or volume of contamination.
5. Short-term effectiveness.
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 EPA's 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.
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Alternative 1 does not reduce risk levels at Landfill No. 1 (there are no identified unacceptable
risks at Landfill No. 6). Alternative 2 consists of using institutional controls to restrict access to
the landfills and reduce exposures potentially associated with direct contact with landfill contents.
This alternative does not involve ground-water or soil remediation; rather, it includes ground-
water monitoring to determine if contaminants in the landfills are moving with or through ground
water. Alternative 3 (applicable to Landfill No. 1 only) does not include treatment of landfill
contents or ground water; however, it includes containment of the landfill contents through
installation of new cover and improvement of existing cover, to reduce potential exposures. This
alternative includes institutional controls similar to Alternative No. 2. Also, under this alternative,
the drainage channel in the western portion of Landfill No. 1 would be realigned, stabilized, and
lined with rip-rap to prevent erosion of the channel into the landfill and the potential transport of
contaminants via the channel. Alternative 3 would provide the greatest overall protection to
human health and the environment for Landfill No. 1.
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, and 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 that do not specifically address a
hazardous substance, pollutant, or remedial action. Rather, these requirements address problems
or situations that are similar to those encountered at a particular CERCLA site. Therefore, the
use of these requirements is suited to the environmental and technical factors at a particular site.
ARARs are grouped into these three categories:
• Chemical-Specific ARARs are health or risk-based numerical values or
methodologies which, 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.
• 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 and a narrative discussion of compliance with ARARs is
provided below for the alternatives considered.
Alternative 1 (No Action);
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The No Action alternative does not comply with State solid waste landfill closure requirements.
The OU-2 RI concluded that ground water that has been contaminated by the contents of Landfill
No. 1 has not moved beyond the boundaries of the landfill; therefore, MCLs are not applicable.
MCLs are applicable at the boundaries of the landfill and would have to be met if contaminated
ground water moved out of the landfill at a later date. Ground water at Landfill No. 6 is in
compliance with Federal MCLs. No State or Federal permits are required for this alternative.
Alternative 2 (Institutional Controls'):
For Landfill No. 1, Alternative 2 does not comply with State solid waste landfill closure
requirements. The OU-2 RI concluded that contaminated ground water is confined within the
boundaries of Landfill No. 1; however, this alternative would not reduce the potential for future
transport of contaminated ground water from beyond the landfill boundary.
For Landfill No. 6, Alternative 2 would meet State landfill closure guidelines. The conditions at
the landfill presently meet State minimum cover requirements. Implementation of institutional
controls would allow Landfill No. 6 to meet other State guidelines for landfills. Ground water at
Landfill No. 6 is in compliance with Federal MCLs.
No Federal or State permits are required for this alternative.
Alternative 3 (Earth Cover/Institutional Controls, Landfill No. 1 only):
Alternative 3 would meet State of South Dakota Waste Management Regulations for the disposal
of solid waste by providing a two-foot minimum earth cover capable of sustaining perennial
vegetation; implementing institutional controls including maintaining access control; filling,
grading, and contouring the site; maintenance of the cover and vegetation; and other
requirements as set forth in ARSD Chapter 74:27:15. The State is Federally authorized for the
Resource Conservation and Recovery Act (RCRA) Subtitle D Municipal Solid Waste Program (8
October 1993, 58 FR 52486). Information from the RI indicates that approximately two feet of
cover material exists over most of Landfill No. 1, with the exception being in the western portion
of landfill. Borings drilled during the pre-design study would be used to determine the quantity of
material required to construct a cover of the required thickness. The pre-design study would also
be used to determine the type of cover needed to reduce infiltration of precipitation through the
landfill and ensure continued compliance with the MCLs. Based on the results of the pre-design
study, either a single-layer earth cover or multi-layered reduced-permeability earth cover would
be constructed. The selected cover would be constructed to comply with State requirements.
Long-term ground-water monitoring would be used to verify compliance with Federal MCLs
(National Primary Drinking Water Regulations, 40 CFR 141.11-12) beyond the boundary of the
landfill. By following the presumptive remedy approach, the MCLs are not considered ARARs
for the ground water within the boundaries of the landfill.
Section 404 of the Clean Water Act (CWA) regulates the discharge of dredge or fill material into
waters of the United States. Section 404 is implemented through regulations set forth at 33 CFR
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parts 320 through 330 and 40 CFR Part 230. Based on the results of the pre-design study, to
fully provide containment of the landfill contents, the drainage channel in the western portion of
the Landfill No. 1 will need to be realigned and lined to prevent erosion. This may adversely
affect an existing wetland. The Executive Order on Protection of Wetlands (E.O. No. 11,990)
requires Federal Agencies to avoid, to the extent possible, the adverse impacts associated with the
destruction or loss of wetlands if a practical alternative exists. If the discharge of fill material into
a water body cannot be avoided, the use of appropriate and practicable mitigation measures to
minimize the adverse impact to the aquatic ecosystem will be required. Appropriate mitigation
measures may be implemented during the remedial action. If lining this channel as part of
Alternative 3 results in adverse impacts to wetlands at OU-2, an alternate area will be chosen for
construction of a new wetland for the mitigation purposes. This ARAR will be met.
2.8.3 Long-Term Effectiveness and Permanence
The assessment of this criterion considered the long-term effectiveness of alternatives in
maintaining protection of human health and the environment after response action objectives have
been met.
Alternative 1 would not provide additional effectiveness or permanence in reducing the potential
for direct contact or ingestion of the surface soil or sediments. No further controls for the OU
would be developed under this alternative.
For Landfill No. 1, Alternative 2 would be effective in reducing direct exposure to landfill
contents by restricting access to the site. Alternative 2 would not reduce the potential for erosion
of the drainage channel into the landfill and would not reduce potential impacts to ground water
from percolation of rainwater through those areas of Landfill No. 1 that are not adequately
covered.
For Landfill No. 6, Alternative 2 would provide long-term effectiveness in reducing exposures to
landfill contents through access restrictions and land-use restrictions. There was no unacceptable
health risk associated with Landfill No. 6, and no ground water contaminated above ARARs. The
existing cover over the landfill has prevented the landfill contents from significantly impacting
underlying ground water.
For both landfills, permanency and reliability would be evaluated through long-term ground-water
monitoring and maintenance of the existing landfill soil cover.
Alternative 3 (applicable to Landfill No. 1 only) provides long-term effectiveness in reducing risk
due to exposure of contaminants in the landfill, and significantly reduces the potential for landfill
contents to impact ground-water quality. Access restrictions would deter unauthorized access to
the site. Installing addition cover and improving existing cover would effectively contain the
contents of the landfill and reduce the potential for exposure to contaminants. Providing positive
drainage off the site would also reduce ponding on the landfill and further reduce the potential for
infiltration. Erosion of the drainage channel into the landfill will be limited by realigning and lining
the channel. The development and maintenance of a vegetated area would limit erosion of the
earth cover. Permanency and reliability would be evaluated through long-term ground-water
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monitoring and maintenance of the existing landfill cover and vegetation.
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 an alternative may employ.
Alternatives 1 and 2 do not reduce toxicity, mobility, or volume of contamination. Alternative 3
reduces the mobility of contaminants in the soil by preventing erosion of the drainage channel into
the landfill and reducing infiltration and potential wind-blown contamination (through installation
of a cover); however, treatment of the contamination is not being proposed.
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
response action objectives have been met.
It is not anticipated that the proposed alternatives would significantly impact worker or
community health and safety during the implementation period. Alternatives 2 and 3 may impact
community and worker health and safety through dust emissions during the initial construction
phase. The impact could be minimized through dust mitigation.
Alternatives 2 and 3 may create a short-term increase in risk during remedial activities due to the
inhalation exposure pathway. Disturbance of surface soil during earthwork could result in
exposure to workers. The use of personal protective equipment and dust mitigation measures
during construction would minimize this potential impact. Alternative 3 could temporarily
increase the opportunity for erosion of the disturbed soils, although erosion and sediment control
measures will help to minimize this adverse impact.
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 for
implementation of the response action.
Alternative 1 requires no implementation because of the No Action scenario.
Alternative 2 requires no special or unique activities and could be implemented using locally
available materials and contractors. Long-term monitoring would indicate whether additional
action would need to be implemented in the future.
Alternative 3 could be implemented with standard construction equipment, materials, and
methods. The availability of an on- or off-Base supply of cover material, and the design of channel
improvements require further consideration during the Remedial Design Analysis. If required,
wetlands mitigation (as a result of potential drainageway modifications) could also be
implemented with standard construction equipment, materials, and methods. Land use (or deed)
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restrictions could be implemented at EAFB using various administrative means.
2.8.7 Cost
The assessment of this criterion considers the capital and operation and maintenance (O&M) costs
associated with each of the alternatives. 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 cost includes 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 evaluate the alternatives
based on the ability to protect human health and the environment for additional costs that may be
incurred. Cost estimates do not include yearly escalation adjustments. A summary of the costs
for each alternative is as follows:
Alternative No. 1 (No Action)
Total Capital Costs
$0
Total Annual (Sampling/ Analysis) Costs = $0
30-Year Present Value for Annual Costs
Annual Cost = $0
Years = 30
Discount Rate = 5%
TOTAL 30-Year Present Value
$0
SO
Alternative No. 2 - Landfill No. 1 (Institutional Controls)
Total Capital Costs
Total Annual (Sampling/ Analysis/O&M) Costs - Years 1-5 = $107,350
Total Annual (Sampling/ Analysis/O&M) Costs - Years 6-30 = $55,650
30-Year Present Value for Annual Costs
Annual Cost - Years 1-5 = $107,350
Annual Cost - Years 6-30 = $55,650
Years = 30
Discount Rate = 5%
TOTAL 30-Year fresent Value
$132,100
$1,079,300
$1,211,400
Alternative No. 2 - Landfill No. 6 (Institutional Controls)
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Alternative No. 2 - Landfill No. 6 (Institutional Controls)
Total Capital Costs
Total Annual (Sampling/ Analysis/O&M) Costs - Years 1-5 = $18,000
Total Annual (Sampling/ Analysis/O&M) Costs - Years 6-30 = $9,500
30-Year Present Value for Annual Costs
Annual Cost - Years 1-5 = $18,000
Annual Cost - Years 6-30 = $9,500
Years = 30
Discount Rate = 5%
TOTAL 30-Year Present Value
$31,200
$182,800
$214,000
Alternative No. 3 - (Single Layer Earth Cover/Institutional Controls)*
(Landfill No. 1 only)
Total Capital Costs
Total Annual (Sampling/Analysis/O&M) Costs - Years 1-5 = $107,350
Total Annual (Sampling/Analysis/O&M) Costs - Years 6-30 = $55,650
30-Year Present Value for Annual Costs
Annual Cost - Years 1-5 = $107,350
Annual Cost - Years 6-30 = $55,650
Years = 30
Discount Rate = 5%
TOTAL 30-Year Present Value
$693,400
$1,079,300
57,772,700
Alternative No. 3 - (Multi-Layer Earth Cover/Institutional Controls)*
(Landfill No. 1 only)
Total Capital Costs
Total Annual (Sampling/Analysis/O&M) Costs - Years 1-5 = $107,350
Total Annual (Sampling/Analysis/O&M) Costs - Years 6-30 = $55,650
30-Year Present Value for Annual Costs
Annual Cost - Years 1-5 = $107,350
Annual Cost - Years 6-30 = $55,650
Years = 30
Discount Rate = 5%
TOTAL 30-Year Present Value
$3,187,600
$1,079,300
$4,266,900
' Note: For Alternative 3, single or multi-layer is dependent on results of the pre-design study. Under the single
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layer option, two feet of cover material will be placed over 2-3 acres of rubble in the western portion of the landfill
that are currently exposed. Over the remaining areas of the landfill, low areas will be filled and the entire area
graded to provide positive drainage off the site. Under the multi-layer option, the reduced permeability cover
would be placed over the entire area of the landfill. Costs for channel improvements are not included in
Alternative 3 and need-to be further evaluated in the Remedial Design Analysis.
2.8.8 State Acceptance
The assessment of this criterion considered the State's preferences for or concerns about the
alternatives.
The State concurs with the selected remedy. The State provided comments on the Remedial
Investigation, Feasibility Study, and Proposed Plan. In accordance with the requirements of the
NCP, the State of South Dakota was also provided the opportunity to review and comment on
the ROD. As a result of that review and 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 their concerns about the selected remedy during the public
comment period. The questions and concerns of the community are discussed 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 in consultation with EPA and the State, the Air Force has determined that the
selected alternative for Landfill No. 1 is Alternative 3, Earth Cover/Institutional Controls. This
alternative includes institutional controls, storm-water channel realignment and lining, in
conjunction with physical modification of the OU to reduce potential risk. The selected
alternative for Landfill No. 6 is Alternative 2, Institutional Controls. This alternative uses access
restrictions, monitoring, and other controls to reduce potential risk. Five-year reviews of the
remedies for both landfills would be required because potential contaminants will remain above
health-based levels following completion of installation of the landfill cover. If the five-year
reviews of the remedies indicate that conditions at landfills have changed, certain aspects of the
selected remedies may be modified to reflect these changes.
For Landfill No. 1, major components of Alternative 3 are:
• Installing an earth cover over the area of attainment at Landfill No 1.
• Institutional controls to restrict future use of the operable unit.
• Realignment and lining of the storm-water channel.
• Providing for longrterm monitoring to identify development of future risks
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associated with the operable unit. Providing long-term maintenance for the
remedial actions taken at the operable unit.
Each of these items are discussed below.
Installation of Soil Cover
A pre-design study would be conducted to verify the defined limits of the landfill and determine
the type of cover needed. It is anticipated that a single-layer earth cover that meets the State
landfill closure requirements will be used. The cover material must be capable of sustaining
vegetation. Information from the remedial investigation indicates that approximately two feet of
cover material exists over most of the landfill, except in the western portion of Landfill No. 1 .
Borings drilled during the pre-design study would be used to determine the quantity of material
required to construct a cover of the required thickness. The pre-design study would also be used
to determine the type of cover needed to reduce infiltration of precipitation through the landfill
and ensure continued compliance with the MCLs.
The 'area of attainment would be filled, graded, and contoured to maintain stability, eliminate
slumping, settling, or ponding of water above previously active disposal areas, and to provide
positive drainage off the landfill area.
Also under this alternative, the following activities would take place:
• Stabilize, realign, and line the banks of the existing storm- water channel in the
western portion of Landfill No. 1 with rip-rap or other energy dissipating material.
This activity is dependent upon the pre-design study.
• Level existing rubble piles.
• Seed under- vegetated areas and areas disturbed by new construction and cover
placement.
If the discharge of fill material into a water body cannot be avoided, the use of appropriate and
practicable mitigation measures to minimize the adverse impact to the aquatic ecosystem will be
required. Appropriate mitigation measures may be implemented during the remedial action. If
lining this channel as part of Alternative 3 results in adverse impacts to wetlands at OU-2, an
alternate area will be chosen for construction of a new wetland for the mitigation purposes.
Institutional Controls
Institutional controls would be implemented to prevent human exposure to contaminated soil and
ground water. These controls will include: (1) issuing a continuing order to restrict onsite worker
access to contaminated soil, and restrict or control temporary construction activities unless proper
protective equipment is worn; (2) filing a notice to the deed detailing the restrictions of the
continuing order and ground-water well restrictions; and (3) a covenant to the deed in the event
of property transfer.
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The continuing order would-be issued by the Installation Commander to restrict access to or
disturbance of the landfills as long as Ellsworth AFB owns the property. Specifically, it would:
• Restrict or place limitations on the installation of any new underground utilities or
. other construction activities in the area of the landfills; thus preventing accidental
exposures to construction workers.
• Provide for the use of proper protective equipment, in the event that access
through the landfill cover is required.
• Require that the integrity of the landfill covers are maintained. Limit future land
uses to non-intrusive activities only. Maintenance of the landfills will require
development of standard operating procedures (SOPs) to provide for inspections
and repairs. To assist with the institutional controls, a fence may be placed around
Landfill No. 1 and authorized personnel would have access through a locked gate.
Access would only be allowed to perform landfill monitoring and maintenance
activities. Warning signs would be posted at both landfills to deter unauthorized
access.
The continuing order also would mandate that, if the landfill covers were ever removed or
destroyed, the area of attainment would be re-evaluated to determine the need for a
replacement cap or other remedial action.
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 property within OU-2 by the United States to any
other person or entity, the Air Force will place covenants in the deed which will restrict access
and prohibit disturbance of the landfill or the remedial action 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.
Long-Term Monitoring and Maintenance
A long-term monitoring program will be developed and implemented during remedial action
and is subject to approval of both EPA and SDDENR. Contaminant concentrations in the
ground water will be monitored to evaluate the effectiveness of the existing landfill cover and
to determine if ground-water contaminants have been transported beyond the landfill
_
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base, South Dakota
boundaries. - --•- —
A maintenance program would be implemented to ensure the long-term integrity on the
remedial action and landfill conditions would be maintained. The maintenance program would
include development of (SOPs) to provide for inspections, repairs, and general maintenance of
the landfills.
For Landfill No. 6, major components of Alternative 2 are:
• Institutional controls to restrict future use of the operable unit.
• Providing for long-term monitoring to identify development of future risks
associated with the operable unit. Providing long-term maintenance for the
remedial actions taken at the operable unit.
The details of the items listed above are the same as to the respective items discussed for the
selected alternative for Landfill No. 1 except that the access restrictions for Landfill No. 6 will
consist of installing restricted access and warning signs only, not installing a fence. A fence
may be installed around Landfill No. 6 if it is determined it is needed during the remedial
design.
These alternatives for Landfill No. 1 and 6, respectively, will meet the remedial action
objectives and reduce the potential risk for OU-2 by reducing the potential for future exposure
to contaminants in the surface soils and by reducing the mobility of potential contaminants in
the landfills.
For Landfill No. 1, Alternative 3 would achieve significant risk reduction by limiting exposure
to landfill materials and to contaminants present in surface soils and would reduce the
potential for future movement of contaminants in the ground water beneath the landfill. For
Landfill No. 6, institutional controls and long-term maintenance of the existing cover would
reduce the potential for erosion and future exposures to landfill contents. The selected
alternatives will be protective of human health and the environment and will comply with
ARARs.
2.10 STATUTORY DETERMINATIONS
The selected remedies meet the statutory requirements of CERCLA as amended by SARA.
These requirements include protection of human health and the environment, compliance with
ARARs, cost effectiveness, utilization of permanent solutions and alternative treatment
technologies to the extent practicable. The statutory preference for treatment is not satisfied;
however, the selected alternative(s) is the presumptive remedy (containment) developed by
EPA for landfills. Containment, by definition, does not attempt to reduce the toxicity or
volume of potentially hazardous materials; rather, it reduces the likelihood of exposure to
these materials by preventing the movement of materials beyond the boundaries of the landfills
and preventing direct contact with landfill materials. The selected remedies represent the best
balance of tradeoffs among the alternatives considered, with respect to pertinent criteria, given
___
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base, South Dakota
the scope of the action.
The manner in which the selected remedy meets each of these requirements is discussed in the
sections below..
2.10.1 Protection of Human Health and the Environment
Implementation of the presumptive remedy (containment by covering) strategy for landfills has
been shown by EPA to meet the remedial action objectives and protect human health and the
environment by preventing (1) direct contact with landfill contents and (2) ingestion of surface
soils and sediments. Specifically, the cover alternative for Landfill No. 1:
• Eliminates exposure to landfill contents by installing an earth cover.
• Reduces the potential infiltration of contaminants to the ground water.
• Reduces the potential for erosion into the landfill by improving the drainage
channel within the boundaries of the landfill.
• Prevents unauthorized access to the area by installing a perimeter fence and
posting restricted access signs.
• Provides for long-term monitoring of ground water to identify potential future
risks associated with OU-2.
• Places land and ground-water use restrictions on the landfill.
Specifically, the institutional controls alternative for Landfill No: 6:
• Deters unauthorized access to the area by posting restricted access and
warning signs.
• Provides for long-term monitoring of ground water to identify potential future
risks associated with OU-2.
• Places land and ground-water use restrictions on the landfill.
2.10.2 Compliance with ARARs
Alternative 3 for Landfill No. 1 will meet State landfill closure requirements by providing the
required amount of cover over the landfill, site improvements, access and land/ground-water
use restrictions, and long-term monitoring/maintenance. Landfill No. 6 already meets
minimum cover requirements and Alternative 2 will comply with additional State landfill
closure requirements. The OU-2 RI concluded that contaminated ground water has not
moved beyond the limits of Landfill No. 1; therefore ground-water ARARs are met at the
boundaries of the landfill. The RI also concluded that the ground water beneath Landfill
• 2^24
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Final Record of Decision Operable Unit 2
— Ellsworth Air-Force Base, South Dakota
No. 6 has not been adversely impacted, therefore ground-waters ARARs are also met at this
landfill. Mitigation of adversely affected wetlands may be required. Additional information
about ARAR compliance is contained in Section 2.8.2.
2.10.3 Cost Effectiveness
The selected remedies for Landfill Nos. 1 and 6 respectively, provide overall effectiveness in
reducing human health risks relative to its costs. The presumptive remedy process ensures
cost effective remedies are chosen. The landfill cover ensures containment of the landfill
contents. Site specific conditions identified during the remedial investigations will be used to
determine the cover type considered for Landfill No. 1. Additional information will be
developed during the pre-design study to determine whether a single-layer or more costly
multi-layer cover would be needed.
2.10.4 Utilization of Permanent Solutions and Alternative Treatment Technologies
to the Extent Possible
EPA has established that installing a proper cover has proven effective in containing landfill
contents. The alternatives for both landfills provide long-term prevention of exposure to
potential landfill material, prevent unauthorized access, and provide for long-term ground-
water monitoring to detect potential movement of chemicals from the area. A five-year
review of the selected remedy will be performed due to the uncertainty of fully characterizing
landfill contents. The review will be conducted no less often than every five years after the
signing of the ROD to ensure the remedy continues to provide adequate protection of human
health and the environment. Results of the review will be used to determine if modification of
any or all parts of the selected remedies will be required.
2.10.5 Preference for Treatment as a Principal Element
Treatment of the landfill contents is not supported based on the findings of the RI for OU-2.
No identifiable hot spots were detected that would warrant removal and/or separate
treatment. The risks associated with OU-2 can be addressed by eliminating exposure to the
landfill contents by installing a cover and restricting access.
2.11 DOCUMENTATION OF SIGNIFICANT CHANGES
The selected actions for Landfill No. 1 and Landfill No. 6 at OU-2, the cover alternative and
institutional controls alternative respectively, are similar to the preferred alternative presented
in the Proposed Plan for OU-2 remedial action. However, there has been a change to that
part of the alternative relating to the drainage channel located in the western portion of
Landfill No. 1. (The Air Force had initially proposed to realign the channel as part of a
Basewide storm-water improvement project. Because the proposed realignment may have
disturbed fill and also impacted wetland areas in the drainage channel, plans for improvement
of this channel were removed from the storm-water project.)
In addition to the installation of a landfill soil cover, Alternative 3 (the preferred alternative for
_
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base, South Dakota
Landfill No. 1) has been modified to include the following channel improvements:
realignment, bank stabilization, and lining. These improvements will reduce the potential for
the channel to erode into the landfill and possibly transport contaminants downstream and off-
Base. The type'of improvements and lining required will be considered during the remedial
design/remedial analysis phase. For purposes of the cost estimate, limited channelization was
considered and rip-rap lining was used along the length of the channel running through
Landfill No. 1 and 100 feet upstream and downstream of the landfill boundaries.
There has also been a change to the preferred alternative for Landfill No. 6. The frequency of
monitoring at Landfill No. 6 has been reduced because there is no unacceptable risk associated
with this landfill. EPA and the State have agreed with this reduced monitoring. The actual
frequency of sampling will be determined in the remedial design/remedial analysis; however, it
is estimated that annual monitoring will be conducted for the first 5 years with biannual
monitoring for the next 25 years. This is the sampling frequency used to develop the revised
cost estimate. The reduced monitoring will result in a significant cost savings for the remedy
at Landfill No. 6. Also, the fencing requirement for Landfill No. 6 has been removed and is
not included in the cost estimate. Access control will be maintained by posting warning signs.
2-26
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base, South Dakota
TABLE 2-1 EVALUATION OF FEDERAL AND STATE ARARS THAT APPLY TO OU-2, ELLSWORTH AFB, SOUTH DAKOTA
A. Potentially Applicable or Relevant and Appropriate Federal Standards, Requirements, Criteria and Limitations
Standard Requirement, Criteria,
or Limitation
Safe Drinking Water Act of 1986
National Primary Drinking
Water Regulations
National Secondary Drinking
Water Standard]
Maximum Contaminant Level
Goali
Clean Water Act of 1977
• Water Quality Criteria
Clean Air Act of 1983
National Primary and
Secondary Ambient Air
Quality Standard
National Emission Standards
for Hazardous Air Pollutants
Solid Wai te Disposal Act » amended by
Resource Conservation and Recovery Act of
1976
Solid Waste Disposal Facility Criteria
Land Disposal Restrictions
Standard Requirement, Criteria,
or Limitation
Citations
42USC300g
40 CFR Part 141. 11-12
40 CFR Part 143.03
40 CFR Part 14 1. 50 A;
Pub. L. No 99-330, 100 Stal. 642 (1986)
33 USC 1251-1376
40 CFR Part 131
42 USC 7401
40 CFR Part 50 1-6, 8.9.11,12, and
Appendices A, II. I. K
40 CFR Part 61 .01
42 USC 6901
40 CFR Parts 257 and 258
40 CFR Part 268
Citations
Description
Specifies maximum chemical contaminant
levels (MCLs) of public water systems.
Establishes secondary maximum contaminant
levels (SMCLs) for public water systems.
These are federally non-enforceable standards
which regulate contaminants in drinking
water that primarily affect the qualities.
Establishes drinking water quality goals set at
levels of unknown or anticipated adverse
health effects, with an adequate margin of
safety.
Sets criteria for water quality based on
toxicity to aquatic organisms and human
health.
Establishes national primary and secondary
ambient air quality standards 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
Description
ARARType
Chemical
Chemical
Chemical
Chemical
Action
Action
Action
Action
ARARType
Applicability
•
Relevant and appropriate for Federal
Class 11 aquifer.
Relevant and appropriate.
Relevant and appropriate.
Relevant and appropriate. Aquifer may
be a Federal Class I1A (discharge to
surface water).
Relevant and Appropriate
Relevant and Appropriate
Relevant and appropriate for addressing
landfill closure performance standards.
Relevant and Appropriate Alternatives
may include the disposal of residual
waste due to treatment.
Applicability
2-27
April 1996
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base, South Dakota
Guideline! for the Land Diipoul of Solid
Waste
40CFR Part 241 100-213
Establishes requirements and procedures for
the disposal of solid waste
Action
Relevant and appropriate for meeting
landfill closure performance guidelines.
Resource Conservation and Recovery Act of
1976
Hazardous Waste Management
System: General
40 CFR Part 260
Establishes definitions as welt as procedures
and criteria for modification or revocation of
any provision in 40 CFR Parts 260-265
Action
Applicable for identifying hazardous
waste during soil placement at OU-2.
Identification and Listing of
Hazardous Wastes
40 CFR Part 261
Defines those solid wastes which are subject
to regulations as hazardous wastes under 40
CFR Parts 262-265 ___
Action
Applicable for identifying hazardous
waste during soil placement at OU-2.
Standards Applicable to
Generators of Hazardous
Wastes
40 CFR Part 262
Establishes standards for generators of
hazardous waste
Action
Applicable to alternatives relating to
removal or ofTsite transport of a
hazardous material.
Standards Applicable to
Transporters of Hazardous
Wastes
40 CFR Part 263
Establishes standards which apply to persons
transporting hazardous waste within the US
if the transportation requires a manifest under
40 CFR Part 262
Action
Applicable for any transport of hazardous
materials offsite.
Standards for Owners and
Operators of Hazardous Waste
TSDF's
40 CFR Part 264
Establishes standards for acceptable
hazardous waste management.
Action
Relevant and Appropriate for
performance guidelines for landfill
closure.
Standards for Owners and
Operators of Hazardous Waste
TSDF's with Interim Status
40 CI-R Part 265
Establishes standards for acceptable
hazardous waste management during interim
status
Action
Relevant and Appropriate for
performance guidelines for landfill
closure.
Toxic Substances Control Act (TSCA)
40 CFR Part 761.1
Substances regulated under this rule include,
but are not limited to. soils and other
materials contaminated as a result of spills
Action
Applicable
Executive Order on Floodplalni Management
Exec. Order No. 11,958
40 USC 7401
40 CFR 6 302(b) & Appendix A
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
Action/Location
Relevant and Appropriate. OU-2 has
identified wetland areas adjacent to the
site.
Executive Order on Protection of Wetlands
Exec. Order No. 11,990
40 CFR 6 302(a) & Appendix A
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
Action/Location
Relevant and Appropriate. OU-2 has
identified wetland areas adjacent to the
site.
B. Potentially Applicable or Relevant and Appropriate State Standards, Requirements, Criteria, and Limitations
Standard Requirement, Criteria,
or Limitation
South Dakota Air Pollution Control
Regulations
Citations
7426:01:09,24.25.26-28
Description
Establishes permit requirements for
construction, amendment, and operation of air
ARARTyne
Action
Applicability
Relevant and Appropriate
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April 1996
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base. South Dakota
South D»koU Waste Management Regulatlbni
South Dikoli Waste Management Regulation*
South Dakota Waile Management Regulation!
South Dakota Waite Management Regulations
South Dakota Waite Management Regulations
South Dakota Water Quality Standardi
South Dakota Remediation Criteria for
Petroleum-Contaminated Sold
South Dakota Water Quality Standardi
South Dakota Ground Water Standards
74:27:03 II
74:26:0304
742703:11
74.27:15
74:28:24:01
74:03:04:02, 10
74:03:32. 33
74:03:04 02. 10
74:03:15
discharge services
Defines requirements for closure of solid
waste disposal facilities.
Establishes requirements for disposal of
hazardous waste in sanitary landfills
Defines requirements for closure of solid
waste disposal facilities
Establishes standards for landfill closure and
postclosure monitoring
Establishes standard for transporters of waste
Defines use of Boxeleder Creek and certain
tributaries.
Establishes requirements for the remediation
of soil contaminated with petroleum products.
Defines use of Boxeleder Creek and certain
tributaries.
Defines ground water classifications by
beneficial use and sets chemical standards.
Action
Action
Action
Action
Action
Action
Chemical
Action
Chemical
Relevant and Appropriate
Relevant and appropriate for landfill
closure performance guidelines.
Relevant and appropriate for landfill
closure performance guidelines.
Relevant and appropriate '
Relevant and appropriate
Relevant and Appropriate
Relevant and appropriate for evaluating
acceptable levels of petroleum products
in the soil.
Relevant and Appropriate
Relevant and appropriate in evaluating
the beneficial use of impacted
groundwater.
nann Wf,
2-29
April 1996
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base, South Dakota
APPENDIX A
FIGURES
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base, South Dakota
3.0 LIST OF ACRONYMS AND ABBREVIATIONS
ACC: Air Combat Command
AFB: Air Force Base
ARARs: Applicable or Relevant and Appropriate Requirements
BTEX: benzene, toluene, ethylbenzene, xylene
CERCLA: Comprehensive Environmental Response, Compensation and Liability Act
COC: Chemicals of Concern
CRP: Community Relations Plan
CWA: Clean Water Act
EAFB: Ellsworth Air Force Base
EPA: Environmental Protection Agency
FAWQ: Federal Ambient Water Quality
IRP: Installation Restoration Program
MCL: Maximum Contaminant Levels
ug/1: Micrograms per liter
mg/1: Milligrams per liter
NCP: National Oil and Hazardous Substances Contingency Plan
NPL: National Priorities List
OU: Operable Unit
PAH: Polynuclear Aromatic Hydrocarbon
ppm: Parts per million by weight
RA: Remedial Action
RAB: Restoration Advisory Board
RAOs: Remedial Action Objectives
RCRA: Resource Conservation and Recovery Act
RI/FS: Remedial Investigation/Feasibility Study
ROD: Record of Decision
SARA: Superfund Amendments and Reauthorization Act
SACM: Superfund Accelerated Cleanup Model
SVOC: Semivolatile Organic Compound
TCE: Trichloroethylene
TPH: Total Petroleum Hydrocarbons
USAGE: United States Army Corps of Engineers
USAF: United States Air Force
VOC: Volatile Organic Compound
3-1
F:\PROJ\6037884\FS\OU-2ROD\FINAL\OU2RODJ!NL
April 1996
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O
2 CM
N
UNNESOTA
NORTH
—
SOUTH DAKOTA
ELLSWORTH AFB
Rapid Oly
Seal* In Mil**
APPROXIMATE
. EUUS WORTH
te^f AIR FORCE BASE
ELLSWORTH AFB
RAPE CITY. SOUTH DAKOTA
AREA LOCATION MAP
ROJECT UCR
DESIGNED BY
DRAWN BY
MRG
CHECKED BY
SCALE
AS SHOWN
DATE
OCT 95
PROJECT NO
60378.84
FIGURE:
2-1
-------
WASTEWATER
TREATMENT
PLANT
1200 .2*00
SCALE IN FEET
LEGEND
OPERABLE UNITS
OU-1 FIRE PROTECTION TRAINING
AREA (FT-01)
OU-2 LANDFILLS 1 ft 6 (LF-02)
OU-3 LANDFILL 2 (LF-03)
OU-4 LANDFILL 3 (LF-CM
OU-5 LANDFILL 4 (LF-05
OU-6 LANDFILL 5 (LF-06
OU-7 LOW LEVEL RADIATION WASTE BURIAL AREA (RW-07)
OU-B EXPLOSIVE ORDNANCE DISPOSAL AREA & PRAMITOL SPILL
OU-9 OLD AUTO HOBBY SHOP AREA (OT-15)
OU-10 " NORTH HANGAR COMPLEX (ST-19)
OU-11 BASEWIOE GROUND WATER
OU-12 HARDFILL NO. 1
-
CM
2«
is
o: <
00
ETL-USWORTH
AIR FORCE BASE
ELLSWORTH AFB
RAPID crrr. SOUTH DAKOTA
SITE LOCATION MAP
ROJECT MCR
DESIGNED BY
DRAWN BY
STAFF
CHECKED BY
SCALE
AS SHOWN
DATE
OCT 95
PROJECT 'NO
60378.84
FIGURE:
2-2
-------
APPROXIMATE OU-2
BOUNDARY
KFNNEY ROAD
REALIGNED DRAINAGE
APPROXIMATE
Rl LANDFILL NO. 6
BOUNDARY
—@— JP-4 JET FUEL LINE
— — SURFACE DRAINAGE
REALIGNED
SURFACE DRAINAGE
APPROXIMATE
Rl LANDFILL NO. 1
BOUNDARY
—— BASE BOUNDARY FENCE
— APPROX. OU2 BOUNDARY
AREA OF CUT AND FILL
TRENCHES
| | AREA OF HARDFILL
I'HOJI Cl NO
60378.84
OU-2
LOCATION OF LANDFILL
NOS. 1 & 6
ELLSWORTH AFB
RAPID CITY. SOUTH DAKOTA
ELLSWORTH
AIR FORCE BASE
.CAI
AS SHOWN
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base. South Dakota
APPENDIX B
RESPONSIVENESS SUMMARY
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base, South Dakota
Responsiveness Summary
Remedial Action at Operable Unit Two
Ellsworth Air Force Base, South Dakota
1. Overview
The United States Air Force (USAF) established a public comment period from August 8 to October
16, 1995 for interested parties to review and comment on remedial alternatives considered and
described in the Proposed Plan for Operable Unit Two (OU-2). 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 September 26, 1995 in the 28th Bomb Wing
Auditorium at Ellsworth Air Force Base (EAFB) to outline the proposed remedy to reduce risk and
control potential hazards at Operable Units 1, 2, and 4.
Some of the public comments pertained to the selected remedies in the Proposed Plans for all the
operable units. Rather than attempting to separate out the comments which pertained to an individual
operable unit, one Responsiveness Summary was prepared to address all the comments for all the
operable units.
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
For OU-2, Landfill No. 1, the selected remedy includes an earth cover with institutional controls and
consists of the following major components:
• Constructing an earth cover, capable of sustaining perennial vegetation, over those
areas of the landfill that are not adequately covered. Filling in low areas and grading
the entire landfill area to provide for positive drainage off the site;
• Institutional controls for the landfill area;
• Long-term ground-water monitoring; and,
B-l
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Final Record of Decision Operable Unit 2
Ellsworth Air Force Base, South Dakota
• Long-term maintenance of soil cover.
• Realignment and lining of the storm-water channel.
For OU-2, Landfill No. 6, the selected remedy is institutional controls and includes the following
major components:
• Institutional controls for the landfill area;
• Long-term ground-water monitoring; and,
• Long-term maintenance of existing cover.
2. Background on Community Involvement
On August 30, 1990 EAFB was listed on the USEPA's National Priorities List (NPL). A Federal
Facilities Agreement (FFA) was signed in January 1992 by the Air Force, EPA, 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, 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 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.
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• Fact sheet. A fact sheet describing the status of the IRP at EAFB was distributed to
the mailingJist 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 at the open
house.
• 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 September 26, 1995
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 Response 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.
The majority of the comments received during the public meeting were in the form of questions about
the remedial investigation findings, the remedial action; i.e., what would be done, how it would be
done, and what effects the action might have. In addition, one question addressed purchase of off-
Base property. Representatives of the USAF were available to provide answers to the questions and
also provided an overview presentation during the meeting to describe the proposed actions.
Part n - Comprehensive Response to Specific Technical, Legal and
Miscellaneous Questions
The comments and questions below, pertaining to OU-2, have been numbered in the order they
appear in the written transcript of the September 26, 1995 public meeting.
Comment 1. Jan Deming
Asked about whether deed restrictions were included in Alternative 3 for OU-2, what
deed restrictions were, and whether they will apply to private land.
Response 1: Deed restrictions restrict land use in the event of a transfer of ownership of the land.
The remedial action under the Record of Decision for OU-2 only addresses the
landfills, which are Air Force property. In the event of transfer of Air Force property,
restrictions will be placed on the deed for Air Force property at OU-2. Since the
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remedial action under Alternative 3 for OU-2 does not address property beyond the
Base boundary, deed restrictions for OU-2 do not apply to private property.
Comment 2. Jan'Deming
Asked about whether the remedial alternative for off-Base ground water would include
any clean up of soil in the off-Base area.
Response 2: The contaminated soil is all within the Base boundary. The remediation in the off-
Base area is aimed at ground water. The contamination carried off-Base by the
flowing ground water. Deeper soils within the ground-water zone are in contact with
the contaminants. When the off-Base ground water is cleaned, the deeper soils will
also be cleaned.
4. Remaining Concerns
Based on review of the transcript of the oral comments received during the public meeting, there are
no outstanding issues associated with implementation of the proposed remedial action.
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