PB96-964403
EPA/ROD/R08-96/114
March 1996
EPA Superfund
Record of Decision:
Ellsworth Air Force Base,
Operable Unit 6, SD
10/18/1995
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Final
Record of Decision for
Remedial Action at Operable Unit 6
Ellsworth Air Force Base, South Dakota
United States Air Force
Air Combat Command
Ellsworth Air Force Base
September 1995
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Final Record of Decision Operable Unit 6
Ellsworth Air Force Base. South Dakota
TABLE OF CONTENTS
Chapter Page
1.0 DECLARATION FOR THE RECORD OF DECISION l-l
1.1 SITE NAME AND LOCATION 1-1
1.2 STATEMENT OF BASIS AND PURPOSE l-l
1.3 ASSESSMENT OF THE SITE 1-1
1.4 DESCRIPTION OF SELECTED REMEDY l-l
1.5 STATUTORY DETERMINATION 1-1
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 OPERABLE UNIT 6 (OU-6) 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 2-5
2.5.3 Ground Water 2-6
2.5.4 Surface Water 2-6
2.6 SITE RISK SUMMARY 2-7
2.7 DESCRIPTION OF ALTERNATIVES 2-9
2.8 SUMMARY OF COMPARATIVE .ANALYSIS OF ALTERNATIVES . . . 2-10
2.8.1 Overall Protection of Human Health and the Environment 2-11
2.8.2 Compliance with ARARs 2-11
2.8.3 Long-Term Effectiveness and Permanence 2-13
2.8.4 Reduction of Toxicity, Mobility, and Volume Through Treatment 2-13
2.8.5 Short-Term Effectiveness 2-13
2.8.6 Implementability 2-14
2.8.7 Cost . 2-14
2.8.8 State Acceptance 2-15
2.8.9 Community Acceptance 2-15
2.9 SELECTED ALTERNATIVE 2-15
2.10 STATUTORY DETERMINATIONS 2-17
2.10.1 Protection of Human Health and the Environment 2-17
2.10.2 Compliance with ARARs 2-17
2.10.3 Cost Effectiveness 2-17
2.10.4 Utilization of Permanent Solutions and Alternative Treatment
Technologies to the Extent Possible 2-18
2.10.5 Preference for Treatment as a Principal Element 2-18
2.11 DOCUMENTATION OF SIGNIFICANT CHANGES 2-18
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base. South Dakota
3.0 LIST OF ACRONYMS AND ABBREVIATIONS 3-1
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 6
Figure 2-4 OU-6 Potentially Affected Wetlands
Figure 2-5 Operable Unit 6 Area of Attainment
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FINAL Record of Decision Operable Unit 6
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1.0 DECLARATION FOR THE RECORD OF DECISION
1.1 SITE NAME AND LOCATION
Operable Unit 6 (OU-6), Landfill No. 5 Area, Ellsworth Air Force Base (EAFB), National
Priorities List Site.
Meade and Pennington Counties, South Dakota
1.2 STATEMENT OF BASIS AND PURPOSE
This decision document describes EAFB's selected remedial action for Operable Unit 6 (OU-6), in
accordance with the Comprehensive Environmental Response. Compensation, and Liability Act of
1980 (CERCLA), as amended by the Superfiind 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-6, EAFB. The US
Environmental Protection Agency (EPA) and the South Dakota Department of Environment and
Natural Resources (SDDENR) concur with the selected remedial action.
13 ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from OU-6, if not addressed by implementing
the response action selected in this Record of Decision (ROD), may present an imminent and
substantial endangerment to public health, welfare, or the environment.
1.4 DESCRIPTION OF SELECTED REMEDY
Twelve potentially contaminated areas, or operable units, have been identified at EAFB. This ROD
is for a remedial action at OU-6 and is the third ROD for EAFB.
The selected alternative, capping, includes the following major components:
Placing a soil cover capable of sustaining perennial vegetation, over the landfill area;
Modification of storm-water discharge point and drainage;
Institutional controls for the landfill area;
Long-term ground-water, surface-water, and sediment monitoring; and,
Long-term maintenance of soil cover.
L5 STATUTORY DETERMINATION
The selected remedy is 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
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remedial action and is cosi-effective. This remedy utilizes permanent solutions and alternative
treatment (or resource recovery) technologies, to the maximum extent practicable for OU-6.
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
landfill 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 hazardous substances remaining on-site beneath the landfill cap
area at low levels, a review will be conducted within five years after commencement of remedial
action to ensure that the remedy continues to provide adequate protection of human health and the
environment.
1.6 SIGNATURE AND AGENCY CONCURRENCE ON THE REMEDY
THAD A. WOLFE j Date
Lieutenant General, US/
Vice Commander
MAX H. DODSON Date
Assistant Regional Administrator
Office of Ecosystems Protection
- "cTna Remediation
ronmental Prrvtection Agency Region VIII
US Envir
'/Ijj
NETTIE H. MYERS, Secretay Date
Department of Environment and Natural Resources
State of South Dakota
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2.0 DECISION SUMMARY
2.1 SITE NAME AND LOCATION
EAFB is a U.S. Air Force 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 OPERABLE UNIT 6 (OU-6) DESCRIPTION/HISTORY AND REGULATORY
OVERSIGHT ACTIVITIES
2.2.1 Description/History
Ellsworth Air Force Base (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 II missile systems. The Air Force has provided support, training,
maintenance, and/or testing facilities. Presently, the 28th Bombardment Wing (B-1B bombers) and
the 99th Tactics and Training Wing are the host units of EAFB.
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.
OU-6 consists of Landfill No. 5 which is approximately seven acres in size and is located in the
southeastern corner of EAFB (Figure 2-3). The landfill was active from 1960 to 1980 and was
primarily used to dispose of construction and demolition debris. Disposal of household waste, shop
waste, and wastewater treatment plant (WWTP) sludge may have taken place. However, no direct
physical evidence of household or hazardous/industrial waste disposal was found at OU-6 during
the 1993 remedial investigation (RJ) field activities. In the past, the OU-6 area was used to stockpile
digested wastewater treatment plant sludge prior to removal by contractors. Portions of the landfill
have been covered, graded, and vegetated. The southern and eastern portions of OU-6 are currently
pan of the EAFB golf course.
Aenal photo analysis conducted by the United States Environmental Protection Agency (EPA) from
historical photos (1938 to 1990) indicated the types of disposal practices at OU-6. Through
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interpretation of these photographs, landfill materials appear to have been placed in the area north
of the east-west drainageway indicated on Figure 2-3. A small building was present in this area at
one time, but has since been removed. Construction and demolition debris material may have been
placed along the railroad embankment on the west side of OU-6. Three small depressions identified
on aerial photos and pre-1984 topographic maps may indicate borrowing activities at OU-6. Utility
maps indicate two storm drain pipes terminating in the landfill. One storm drain discharged into the
largest of the borrow pits. According to EAFB grounds personnel, this pipe was disconnected from
service but never removed. The second storm drain is active and collects runoff from the fuel storage
area west of OU-6.
The topography at OU-6 is characterized by an east-west drainageway in the southern portion of
OU-6 and a north-south stream in the eastern portion of the OU. The drainageway and stream areas
both contain wetlands which are illustrated on Figure 2-4.
The shallow aquifer at EAFB is considered a potential drinking water source and possibly discharges
to the surface. The ground water is classified as having a beneficial use as a drinking water supply
suitable for human consumption (S.D. Chapter 74:03:15, Groundwater Quality Standards).
Deeper bedrock aquifers also exist beneath EAFB. These deeper aquifers are separated from the
shallow aquifer by 800 feet of impermeable clays and silts. In the past, EAFB utilized these deeper
aquifers for its water supply. Presently, EAFB obtains its potable water from the Rapid City
Municipal Distribution System.
2.2.2 Regulatory Oversight Activities
On August 30, 1990 (55 Federal Register 35509), EAFB was listed on the U.S. EPA's National
Priorities List (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 the Comprehensive Environmental
Response. Compensation, and Liabilities 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). It also states the oversight procedures for EPA and
the State to ensure Air Force compliance with the specific requirements. The FFA identified 11
potential source-area operable units as well as a Base-wide ground-water operable unit.
Listing on the NPL and execution of the FFA required the U.S. Air Force to perform a remedial
investigation/feasibility study (RI/FS) to investigate the 12 operable units. In 1993 and 1994, an
extensive RI field program was conducted to characterize conditions at OU-6. The program included
completion of boreholes, installation of monitoring wells, 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.
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23 HIGHLIGHTS OF COMMUNITY PARTICIPATION
Community relations activities that have taken place at EAFB to date include:
FFA process. After preparation of the FFA by the USAF, EPA, and SDDENR, the
document was published for comment. The FFA became effective April 1, 1992.
Administrative Record. An Administrative Record for information was established in
Building 8203 at EAFB. The Administrative Record contains information used to support
USAF decision-making. All the documents in the Administrative Record are available to
the public.
Information repositories. An Administrative Record outline is located at the Rapid City
Library (public repository).
Community Relations Plan (CRP). The CRP was prepared and has been accepted by EPA
and the State of South Dakota and is currently being carried out. An update to this plan will
be prepared in 1995.
Restoration Advisory Board (RAB). The RAB has been formed to facilitate public input
in the cleanup and meets quarterly. In addition to USAF, EPA, and South Dakota oversight
personnel, the RAB includes community leaders and local representatives from the
surrounding area.
Mailing list. A mailing list of all interested parties in the community is maintained by
EAFB and updated regularly.
Fact sheet. A fact sheet describing the status of the IRP at EAFB was distributed to the
mailing list addressees in 1992.
Open house. An informational meeting on the status of the IRP and other environmental
efforts at EAFB was held on May 6, 1993.
Newspaper articles. Articles have been written for the base newspaper regarding IRP
activity.
Proposed Plan. The proposed plan on this action was distributed to the mailing list
addressees for their comments.
A public comment period was held from July 6 to August 5, 1995, and a public meeting was held
on July 25, 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 Record of Decision (ROD).
This ROD is based on the contents of the Administrative Record for OU-6, in accordance with the
CERCLA, as amended by SARA, and the NCP. The RI/FS reports and the Proposed Plan for OU-6
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provide information about OU-6 and the selected remedy. These documents are available at the
Information Repositories at EAFB and the Rapid City Public Library.
2.4 SCOPE AND ROLE OF RESPONSE ACTION
The FFA identified 11 potential source area operable units (OUs) as well as a Base-wide ground-
water operable unit. The 12 operable units are identified as follows:
OU-1 Fire Protection Training Area
OU-2 Landfills Nos. 1 and 6
OU-3 Landfill No. 2
OU-4 Landfill No. 3
OU-5 Landfill No. 4
OU-6 Landfill No. 5
OU-7 Weapons Storage Area
OU-8 Explosive Ordnance Disposal Area (Pramitol Spill)
OU-9 Old Auto Hobby Shop Area
OU-10 North Hangar Complex
OU-11 Base-wide Ground Water
OU-12 HardfillNo. 1
This ROD is to document the selected remedy for the preferred remedial action (RA) at OU-6 and
is the third 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
landfill through containment.
The development of alternatives for the landfill was conducted under EPA's Presumptive Remedies
Approach [Presumptive Remedies: Policy and Procedures (EPA 1993a); Presumptive Remedy for
CERCLA Municipal Landfill Sites (EPA 1993b)]. By 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 capping, would remove risk associated with the ingestion, dermal contact,
and inhalation exposure pathways. The area of attainment defines the area over which preliminary
remediation goals would be achieved, and is based on the RAOs. The area of attainment would
include landfill areas not meeting appropriate closure standards. No consideration of leachate or gas
production was addressed, since identified wastes placed in the landfill are not likely to produce
significant amounts of gas, or does the waste typify that which would normally be associated with
leachate production. Furthermore, sample results indicate ground water has not been impacted by
leachate.
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2.5 SITE CHARACTERISTICS
This section describes the presence and distribution of contaminants at OU-6 as a result of past
activities.
2.5.1 Soils
Polynuclear Aromatic Hydrocarbons (PAHs)
PAHs were reported in several surface soil samples and in one subsurface soil sample. No specific
pattern of PAH contamination exists in the surface soil. The subsurface soil contamination is
believed to be associated with asphalt material found in the landfill during the RI. Because of
uncertainties associated with characterizing the contents of landfills, the PAHs were evaluated in the
risk assessment.
Pesticides
Low concentrations of pesticides were reported in many of the surface soil samples, but in only one
subsurface sample. The pesticides are from past pesticide application practices at EAFB, not from
the landfill activities. Supporting this conclusion is that the ground water beneath and downgradient
of the landfill did not contain pesticides. Had pesticides been leached from the landfill, the ground
water would have contained the contaminants.
Inorganic Contaminants
The concentrations of several inorganic compounds in the soil samples exist at levels above
background concentrations. This may be due to a combination of the 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.
2.5.2 Sediment
Organic Contaminants
Organic contaminants reported in sediment samples include volatile organic compounds (VOCs),
semivolatile organic compounds (SVOCs) and pesticides. Sample results from certain locations
indicate that the detected contaminants originated from surface water runoff from other areas of
EAFB and are not a result of the landfill activities. However, these contaminants were still evaluated
in the risk assessment.
Inorganic Contaminants
Inorganic compounds were detected in the sediment samples from the drainageways. Arsenic and
other inorganic compounds are within the range of naturally occurring concentrations. However, due
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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 do not indicate any discernable ground water contamination at OU-6.
Low levels of certain contaminants were intermittently detected in ground water samples from
isolated areas.
Organic Contaminants
One sample from a well upgradient of the landfill contained trichloroethylene (TCE), a commonly
used solvent, at 5 micrograms per liter (Mg/L); however, TCE was not detected in ground water
samples from beneath or downgradient of the landfill. Chrysene, a component of jet fuel, was
detected in one sample at a concentration of 2 ^g/L. Chrysene was not detected in any other ground-
water sample. The TCE detected in the upgradient well will be further investigated during the OU-11
Basewide ground water investigation.
Inorganic Contaminants
Inorganic compounds were detected in ground water samples, but at concentrations within the range
of naturally occurring characteristics. However, because of uncertainties associated in determining
the natural characteristics, zinc and lead were evaluated in the risk assessment.
2.5.4 Surface Water
Organic Contaminants
Several organic contaminants were detected in surface water samples taken from the drainageways.
In the surrounding surface soil samples, these same contaminants were either not detected or were
detected at very low concehtrations. Based on this and the surface water sampling locations, the
majority of the surface water contaminants are from storm water runoff from the refueling area,
upgradient of OU-6. The contaminants were evaluated in the risk assessment to facilitate the
investigations of the sources of the surface water contamination.
Inorganic Contaminants
Several inorganic compounds were detected in the surface water samples. The concentrations of
these compounds are within the range of naturally occurring characteristics. However, due to
uncertainties associated with determining the natural characteristics, these compound were still
evaluated in the risk assessment.
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2.6 SITE RISK SUMMARY
Human Health Risks
The assessment of human health risks for this OU considered the following topics:
(1) Contaminants of concern (COCs) in ground-water, surface water, sediment, and soil
samples taken at OU-6;
(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) ToxicityoftheCOCsiand
(7) Uncertainties in the assessments of exposure, toxicity, and general risks.
Noncarcinogenic and carcinogenic risks were calculated for the following five potential exposure
groups:
(1) Current EAFB maintenance personnel mowing grass on-site;
(2) The future child/adult living on-site who ingests surface soil;
(3) The future adult living on-site who ingests and showers with shallow ground water;
(4) Future adolescents who are exposed to surface water and sediment through wading;, and,
(5) Future adult construction workers who excavate on-site for building residences.
Due to the heterogeneity of the waste materials present within the landfill, 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 (EPA 540-F-93-035). The presumptive remedy for landfills is containment
(capping) 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
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OU-6 include (1) direct physical contact with the landfill contents and (2) consumption or contact
with ground water that may become contaminated.
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-6. Carcinogenic risks were estimated as the incremental probability of an
individual developing cancer over a lifetime as a result of exposure to a potential cancer causing
chemical. The acceptable risk range expressed as a probability is one cancer incident in one-hundred
thousand people to one cancer incident in a million people. This level of risk is also denoted by 1
x 10~* 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 potential risks and are excess (i.e., over background) cancer risks due to exposure from
contaminants at the OU.
The risk assessment for OU-6 indicated that the total site risk is within the acceptable risk range. Part
of the total site risk includes risk from exposure to surface soil contaminants from within the landfill.
The chemicals which contributed the majority of the risk in the soil were PAHs and manganese.
Benzo(a)pyrene (a PAH) is one of the primary contaminants identified in the risk assessment.
However, only three of the eleven surface soil samples actually contained concentrations of
benzo(a)pyrene that are of concern. Manganese was higher than background samples as a result of
variations in soil mineralogy. However, due to the heterogeneity of the landfill contents, great
uncertainty is associated with the calculated risk values for the surface soil. Remedial action is
warranted for the landfill based on the uncertainty in characterizing the contents. The presumptive
remedy as stated above was used as a guide to determine the appropriate remedial action.
Arsenic in the sediment of the drainage areas also contributed to the total site risk. The highest
concentration of arsenic in sediment was associated with a sample from a depression in the southern
drainage. It is typical for naturally occurring compounds to settle or become trapped in depression
areas of drainage areas. The arsenic in the sediment is not associated with the landfill. Remedial
action for the drainage areas outside of the landfill boundary is not warranted.
Results of the risk assessment indicated shallow ground water and surface water were not media of
current concern. Therefore, remedial action is not warranted for the ground water and surface water
at this time. The ground water at OU-6 will still be part of the Base-wide ground water evaluation
forOU-11.
Ecological Risks
An ecological risk evaluation of OU-6 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-6 habitats, particularly in the drainage
channels. These species include various types of invertebrates, amphibians, birds, and mammals.
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Because of the altered natural environment at OU-6, rare, threatened, or endangered species are
unlikely to utilize the area for more than brief, periodic habitat.
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.
Findings of the RI indicate that the contaminants at OU-6 are not altering the ecology to noticeable
levels. A Base-wide ecological risk assessment will be conducted as part of OU-11, and OU-6 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 abbreviated feasibility study (FS). The OSWER directive established containment
of the contamination within the landfill and the collection and treatment of landfill gas and
contaminated ground water within the landfill boundary as the presumptive remedy for CERCLA
municipal landfills.
Although not specifically identified as a municipal landfill, OU-6 exhibits characteristics that make
this presumptive remedy applicable. The landfill contents at OU-6 do not have the characteristics
to produce any significant leachate or gas. The risk assessment did not identify the ground water as
a pathway of concern. Even though the landfill contents were not identified as a source of
unacceptable risk to human health, the heterogeneity of the landfill contents causes uncertainties in
the risk assessment. Therefore, the presumptive remedy focuses on containment of the landfill
contents.
Alternative 1
No Action
The no action alternative represents the baseline condition at OU-6 and refers
to taking no further action at OU-6 other than monitoring of sediment, surface
water, and ground water.
Alternative 2 - Institutional Controls
Institutional controls (access restrictions and deed restrictions).
Monitoring of ground water, surface water, and sediment.
Long-term maintenance of existing soil cover.
Alternative 3-Capping
Monitoring and institutional controls as stated in Alternative 2.
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Place soil cover capable of sustaining vegetation on the area of attainment at the
landfill.
Modification of storm-water discharge point and drainage.
Long-term maintenance of soil cover.
2.8 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
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-6.
The remedial action objectives for OU-6 are as follows:
Landfill
Prevent dermal contact and ingestion of surface soils within OU-6.
Reduce the mobility of potential contaminants in the landfill.
Sediment
Prevent the ingestion of sediments within OU-6.
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-6 is the extent of Landfill No. 5 which is
approximately seven acres in size (Figure 2-5).
Pursuant to Section 300.430(e)(9)(iii) of the EPA's revised National Contingency Plan, 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
the EPA's evaluation criteria.
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base, South Dakota
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.
Alternative 1 (no action) does nothing to reduce risk at OU-6. While the risk assessment did indicate
risk associated primarily with PAHs. the levels of PAHs are within those of anthropogenic levels
of other industrial and agricultural areas. Alternative 2 (Institutional Controls) provides for care of
the OU through maintenance of erosional and/or non-vegetated areas. Access restrictions would
reduce risk by reducing exposure. Alternative 3 (Capping) provides containment (cover) of the
surface soil and the landfill contents. This would eliminate risk associated with exposure to soil and
the future risk associated with potentially contaminated ground water. Alternative 3 also includes
repair and extension of an existing storm water drain and relocation of the east to west drainageway
which will result in reduced surface water impacts to sediment within the OU.
2.8.2 Compliance with ARARs
Alternatives are assessed under this criterion in terms of compliance with ARARs. Applicable
requirements include cleanup standards, standards of control and other substantive environmental
protection requirements, criteria or limitations promulgated under Federal or state laws that
specifically address a hazardous substance, pollutant, contaminant, remedial action, location or other
circumstances at a CERCLA site.
Relevant and appropriate requirements address problems or situations sufficiently similar to those
encountered at a CERCLA site that their use is well suited to the environmental and technical factors
at a particular site. ARARs are grouped into 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-SpecificARARs 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.
W:\55202\REPORTS'WALS\Ol'6ROD.EPA 2-11 September, 1995
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base, South Dakota
Alternative 1 (No Action):
The No Action alternative does not comply with State solid waste landfill closure requirements. The
OU-6 RI concluded that ground water has not been adversely affected and was not a potential
transport pathway; therefore ground water ARARs at the OU are met. No permits are required for
this alternative. Alternative 1 does not meet the remedial action objectives for OU-6. An action would
not be taken to prevent human contact with surface-soil contaminants and potential contaminants
within the landfill may leach to the ground water.
Alternative 2 (Institutional Controls):
Alternative 2 does not comply with State of South Dakota solid waste landfill closure requirements.
The OU-6 RI concluded that ground water has not been adversely affected and was not a potential
transport pathway; therefore ground water ARARs at the OU are met. No Federal or State permits
are required for this alternative. Alternative 2 does not meet the remedial action objectives for OU-6.
Alternative 3 (Capping):
Alternative 3 will meet State of South Dakota Waste Management Regulations for the disposal of
solid waste by providing containment of landfill contents, access/development restrictions, and long-
term monitoring. Information from the remedial investigation indicates that approximately one to two
feet of cover material exists over the landfill. The exact cover thicknesses throughout the entire
landfill are unknown. The State requires a minimum of two feet of cover material. Additional cover
material (a minimum of one foot in depth) will be added under this alternative to achieve compliance
with the State requirements. 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).
The resulting cover will also ensure continued compliance with the Safe Drinking Water Act
Maximum Contaminant Levels (MCLs) by preventing the downward transport of contaminants to
the ground water
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
parts 320 through 330 and 40 CFR Part 230. To folly cover the landfill, the wetlands near the storm
drain discharge points must be filled. This may adversely affect a water of the United States. The
Executive Order on Protection of Wetlands (E.G. 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 wetlands at OU-6 will be adversely effected, an alternate area will be chosen for
construction of a new wetland for the mitigation purposes. This ARAR will be met.
Implementation of the presumptive remedy (containment by capping) strategy for landfills has been
shown by EPA to meet the remedial action objectives by preventing direct contact with landfill
contents and ingestion of surface soils and sediments.
W\55202\REPOKrSWNALS\OU6ROD£PA 2-12 September, 1995
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base. South Dakota
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.
Alternative 2 would provide for increased effectiveness of access restrictions (in addition to the
general EAFB access restrictions). Additionally, vegetation maintenance would reduce erosion
potential. Permanency and reliability of these controls would be enhanced through long-term
monitoring and maintenance of the OU. Uncertainties exist for the ability to provide long-term
access restrictions.
Alternative 3 would offer the highest level of long-term effectiveness. Reduction of risk would be
accorded by the soil cap. Erosion would be limited by the development and maintenance of a
vegetated area. Upon completion, long-term maintenance of the cover and monitoring of ground
water would be provided. Future land uses will be allowed for the landfill only if the integrity of the
landfill cover is not compromised.
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.
Alternative 1 would not provide for the reduction of toxicity, mobility, or volume of the chemicals
of concern in the surface soil and sediment. Alternative 2 would reduce the mobility of contaminants
in surface soils through long-term erosion maintenance of existing cover soils. Alternative 3 does
not use treatment technologies, but reduces the mobility of the contaminants in surface soils in the
landfill area through containment.
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 through earthwork and soil disturbance
would result in exposure to workers. Dust mitigation during these activities would minimize this
W:\S5202\REPORTS\FI\ALS\OU6ROD.EPA 2-13 September, 1995
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base. South Dakota
potential impact. Alternative 3 would present the potential for temporarily increasing 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 would not be difficult to implement since, aside from long-term monitoring using
existing monitoring wells, no further action would be undertaken.
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 will require further consideration
during the Remedial Design Analysis. Wetlands mitigation (as a result of drainageway
modifications) could also be implemented with standard construction equipment, materials, and
methods. Land use (or deed) restrictions can be implemented at EAFB by 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 include the sum of the direct capital costs (materials and labor) and indirect capital costs
(engineering, licenses, permits). Long-term O&M costs include labor, materials, energy, equipment
replacement, disposal, and sampling necessary to ensure the future effectiveness of the alternative.
The objective of the cost analysis is to eliminate those alternatives that do not provide measurably
greater protection of human health and the environment for additional costs that may be incurred.
A summarv of the costs for each alternative is as follows:
Alternative No. I (No Action)
Total Capital Costs
Total Annual (Sampling1 Analysis) Costs
30- Year Present Value for Annual Costs
Annual Cost = S 13,500
Years = 30
Discount Rate = 5%
TOTAL 30 Year Present Value
$0
$13.500
$93.700
593,700
W-\55202\REPORTS\FI\'ALS\OL'6ROD.EPA 2-14 September, 1995
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base. South Dakota
Alternative No. 2 (Institutional Controls)
Total Capital Costs
Total Annual (Sampling/Anaiysis/O&M) Costs
30- Year Present Value for Annual Costs
Annual Cost = $25,000
Years = 30
Discount Rate = 5%
TOTAL 30 Year Present Value
$48.300
S25.000
$173,500
322L800
Alternative No. 3 (Capping)
Total Capital Costs
Total Annual (Sampling/Analysis/O&M) Costs
30- Year Present Value for Annual Costs
Annual Cost = S25,000
Years = 30
Discount Rate = 5%
TOTAL 30 Year Present Value
$505,000
$25.000
$173,500
5678,500
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, Proposed Plan, and this ROD. After incorporating adequate responses
to the comments into the respective documents, the State concurred with the remedy.
2.8.9 Community Acceptance
Comments offered by the public were used to assess the community acceptance of the proposed
alternative. The community expressed 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
is Alternative 3, Capping. This alternative includes institutional controls in conjunction with physical
modification of the OU to reduce potential risk. Five-year review of the remedy will be required
W.\55202\REPORTS\F1NAIS>OL'6ROD.EPA
2-15
September, 1995
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base. South Dakota
because potential contaminants will remain at OU-6 following completion of remedial action. Major
components of Alternative 3 are:
Installation of fencing to control physical access to the landfill area. Posting the area
to indicate the landfill is closed to further use.
Implementing institutional controls (deed and land use restrictions) to prevent future
use of the area for residential use and/or limiting its use to industrial uses.
Providing a minimum of one foot of suitable earthen cover over the area of
attainment (approximately seven acres).
Grading and contouring the area to maintain stability and route surface water
precipitation away from previously active fill areas and prevent ponding of the water.
Extending an existing stormwater drain to the south and east of the landfill area to
prevent the erosion of fill material and future potential contact with contaminated
sediment.
Providing and maintaining suitable vegetation to enhance evapotranspiration and
reduce infiltration and soil erosion.
Mitigating any wetlands affected by placement of the cap.
Providing for long-term ground-water, surface-water, and sediment monitoring at the
OU to identify development of future risks associated with the OU. Providing long-
term maintenance of the remedial actions taken at the OU.
This alternative will meet the remedial action objectives and reduce the potential risk for OU-6 by
preventing future exposure to contaminants in the surface soils and by reducing the mobility of
potential contaminants in the landfill. This will be achieved by the construction of the landfill cap
and maintenance and modification of stormwater drainageways.
This alternative meets the statutory requirements of Section 121 of CERCLA as amended by SARA.
These statutory requirements include protectiveness of human health and the environment,
compliance with ARARs, cost effectiveness, and use of permanent solutions and alternative
treatment technologies to the extent practicable.
The statutory preference for treatment is not satisfied; however, the selected alternative is the
presumptive remedy (containment) developed by EPA for landfills.
Alternative 3 would achieve significant risk reduction by limiting exposure to landfill materials and
to contaminants present in surface soils and sediment at the OU. The selected alternative will be
protective of human health and the environment and will comply with ARARs.
W:\55202\REPORTS\FMALS\OU6ROD.EPA 2-76 September, 1995
\
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base. South Dakota
2.10 STATUTORY DETERMINATIONS
The selected remedy meets the statutory requirements of CERCLA as amended by SARA. These
requirements include protection of human health and the environment, compliance with ARARs,
cost effectiveness, utilization of permanent solutions and alternative treatment technologies to the
extent practicable. 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 landfill and preventing direct
contact with landfill materials. The selected remedy represents the best balance of tradeoffs among
the alternatives considered, with respect to pertinent criteria, given 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
The selected remedy addresses health and environmental issues that were identified in the OU-6 RI
report. Specifically, the capping alternative:
Eliminates exposure to landfill contents by installing an earthen cap.
Reduces the potential infiltration of contaminants to the ground water.
Prevents unauthorized access to the area by installing a perimeter fence and restricted
access signs.
Provides for long-term monitoring of ground water to identify potential future risks
associated with OU-6.
2.10.2 Compliance with ARARs
Alternative 3 will meet State landfill closure requirements by providing containment of landfill
contents, access/development restrictions and long-term monitoring. The OU-6 RI concluded that
ground water has not been adversely affected and was not a potential transport pathway; therefore
ground water ARARs at the OU are met. Wetlands adversely affected by the remedial activities may
need to be mitigated. Additional information about ARAR compliance is contained in Section 2.8.2.
Implementation of the presumptive remedy (containment by capping) strategy for landfills has been
shown by EPA to meet the remedial action objectives by preventing direct contact with landfill
contents and ingestion of surface soils and sediments.
2.103 Cost Effectiveness
The selected remedy provides overall effectiveness in reducing human health risks relative to its
costs. The presumptive remedy process insures cost effective remedies are chosen. The chosen
landfill cover type ensures containment of the landfill contents. Site specific conditions were used
W:\55202\REPORTS\F1XALS\OU6RODEPA
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September, 1995
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base. South Dakota
to determine the type of cover necessary for the landfill. Based on the information provided during
the remedial investigation, a more costly landfill cover would not be cost effective.
2.10.4 Utilization of Permanent Solutions and Alternative Treatment Technologies to the
Extent Possible
EPA has established that proper capping has proven effective in containing landfill contents. This
alternative provides long-term prevention of exposure to potential landfill material, prevents
unauthorized access, and provides for long-term ground water monitoring to detect movement of
chemicals from the area. A five-year review of the selected remedy will be performed due to the
uncertainty of the landfill contents. The review will be conducted five years after the
commencement of the remedial action to ensure the remedy continues to provide adequate protection
of human health and the environment.
2.10.5 Preference for Treatment as a Principal Element
Treatment of the landfill contents is not supported based on the findings of the remedial investigation
for OU-6. No identifiable hot spots were reported present and the risks associated with OU-6 can
be addressed by eliminating exposure to the landfill contents by capping.
2.11 DOCUMENTATION OF SIGNIFICANT CHANGES
The selected action is the same as the preferred alternative presented in the Proposed Plan for OU-6
remedial action. There have been no changes relative to the Proposed Plan.
W:\55202\REPORTS(FKALS\OU6ROD.EPA 2-18 September. 1995
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TABLE 2-1 EVALUATION OF FEDERAL AND STATE ARARS THAT APPLY TO OU-6, ELLSWORTH AFB, SOU HI DAKOTA
Applicable or Relevant and Appropriate Federal Standards, Requirements, Criteria and Limitations
Standard, Requirement, Criteria or
Limitation
Safe Drinking Water Act
National Primary Drinking Water
Standards
National Secondary Drinking
Water Standards
Maximum Contaminant Level
Goals
Clean Water Act
Water Quality Criteria
Criteria and Standards for the
National Pollutant Discharge
Elimination System
Toxic Substances Control Act
Archaeological and Historic
Preservation Act
Citations
42 USC 300, f, g
40CFRPart 141
40CFRPart 143
Public Law No. 99-
330, lOOStat. 642
(1986)
33 USC 1251-1376
40CFRPart 131
40CFRPart 125
40 CFR Part 761
16 USC 469
40 CFR Part 6.301 (c)
Description
Establishes health based standards for
public water systems (maximum
contaminant levels)
Establishes aesthetic based standards
for public water systems (maximum
contaminant levels)
Rstahlishes drinking water quality
goals set at concentrations of unknown
or anticipated adverse health effects
with an adequate margin of safety
Establishes criteria for water quality
based on toxicity to aquatic organisms
and human health
Establishes criteria and standards for
technology-based requirements in
permits under the Clean Water Act
Substances regulated include, but are
hot limited to, soils and other materials
contaminated as a result of spills
Establishes procedures to provide for
preservation of historical and
archaeological data which might be
destroyed through alteration of terrain
as a result of a federal construction
project for a federal licensed activity
or program
ARAR Type
Chemical
Chemical
Chemical
Chemical
Chemical
Action
Location
Applicability
Relevant and appropriate for
federal Class II aquifers.
Relevant and appropriate.
Relevant and appropriate
Relevant and appropriate.
Aquifer may be a federal
Class II A (discharge to
surface water).
Relevant and appropriate.
Applicable.
Applicable. OU-6 was used
for landfilling activities. No
known historic or
archaeological value, although
no confirmation study has
been performed. Applicability
will be determined during RD.
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TABLE 2-1 EVALUATION OF FEDERAL AND STATE ARARS Tl I AT MAY APPLY TO OU-6, E^LS WORTII AFB, SOU III DAKOTA
(Continued)
Potentially Applicable or Relevant and Appropriate Federal Standards, Requirements, Criteria and Limitations
Standard, Requirement, Criteria or
Limitation
Executive Order on Protection of
Wetlands
Citations
E.G. No. 11,990
40 CFR 6.302(a) &
Appendix A
Description
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
ARAR Type
Action/Location
Applicability
Applicable.
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TABLE 2-1 EVALUATION OF FEDERAL AND STATE ARARS THAT APPLY TO OU-6, ELL^WORTI I AFB, SOUTII DAKOTA
(Continued)
Applicable or Relevant and Appropriate State Standards, Requirements, Criteria and Limitations
Standard, Requirement, Criteria or
Limitation
South Dakota Waste Management
Regulations
South Dakota Waste Management
Regulations
South Dakota Waste Management
Regulations
South Dakota Waste Management
Regulations
South Dakota Water Quality
Standards
South Dakota Ground Water
Standards
South Dakota Surface Water
Quality Standards
South Dakota Remediation
Criteria for Petroleum-
Contaminated Soils
Citations
74:26:03:04
74:27:03:11
74:27:09:06
74:27:15
74:03:04:02, 10
74:03:15
74:03:02
74:03:32
Description
Establishes requirements for disposal
of hazardous wastes in sanitary
landfills
Defines requirements for closure of
solid waste disposal facilities
Defines criteria for permit applications
for other solid waste TSD facilities
Establishes standards for landfill
closure and post-closure monitoring
Defines use of Box Elder Creek and
certain tributaries
Defines ground water classifications
by beneficial use and sets chemical
standards
Establishes surface water quality
standards.
Establishes requirements for the
remediation of soil contaminated with
petroleum products.
ARAR Type
Action
Action
Action
Action
Action
Chemical
Chemical
Chemical
Applicability
Relevant and appropriate.
Relevant and appropriate.
Relevant and appropriate.
Relevant and appropriate.
Relevant and appropriate.
Relevant and appropriate.
Relevant and appropriate.
Relevant and appropriate.
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base. South Dakota
3.0 LIST OF ACRONYMS AND ABBREVIATIONS
ACC: Air Combat Command
AF: Air Force
AFB: Air Force Base
ARARs: Applicable or Relevant and Appropriate Requirements
CERCLA: Comprehensive Environmental Response, Compensation and Liability Act
COC: Chemicals of Concern
DNAPL: Dense non-aqueous phase liquid
EAFB: Ellsworth Air Force Base
EP: Extraction Procedure, the EPA's standard laboratory procedure for leachate generation.
EPA: Environmental Protection Agency
FFA: Federal Facilities Agreement
FPTA: Fire Protection Training Area
FTA: Fire Training Area
GPR: Ground Penetrating Radar
HQ: Headquarters
IN SITU: In the original place.
IRIS: Integrated Risk Information System
IRP: Installation Restoration Program
JP-4: Jet Propulsion Fuel Number Four; contains both kerosene and gasoline fractions.
LNAPL: Light Non-Aqueous Phase Liquid
MCL: Maximum Contaminant Levels
mgd: Million Gallons per Day
Mg/1: Micrograms per liter
mg/1: Milligrams per liter
MSL: Mean Sea Level
NAPL: Non Aqueous Phase Liquid
NCP: National Oil and Hazardous Substances Contingency Plan
NEPA: National Environmental Policy Act
NPDES: National Pollutant Discharge Elimination System
NPDWR: National Primary Drinking Water Regulations
NPL: National Priorities List
OU: Operable Unit
O&G: Symbols for oil and grease
PAH: Poly nuclear Aromatic Hydrocarbon
PCB: Polychlorinated Biphenyl; liquids used as a dielectrics in electrical equipment
W:\55202\REPORTS\F1XALS\OU6ROD.EPA
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September, 1995
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base. South Dakota
PCE: Perchloroethylene: liquids used in degreasing or paint removal.
PL: Public Law
ppm: Parts per million by weight
RCRA: Resource Conservation and Recovery Act
RI/FS: Remedial InvestigatioaTeasibility Study
SARA: Superfund .Amendments and Reauthorization Act
SACM: Superfund Accelerated Cleanup Model
SVOC: Semivolatile Organic Compound
TCA: -1,1,1,-tetrachloroethane
TCE: Trichloroethylene
TCL: Target Compound List
TCLP: Toxicity Characteristic Leaching Procedure
IDS: Total Dissolved Solids
TOC: Total Organic Carbon
TSD: Treatment, storage or disposal sites/methods
USAF: United States Air Force
U.S. EPA: United States Environmental Protection Agency
USDA: United States Department of Agriculture
USFWS: Unites States Fish and Wildlife Service
USGS: United States Geological Survey
VES: Vertical Electrical Sounding
VOC: Volatile Organic Compound
WQC: Water Quality Criteria
WWTP: Wastewater Treatment Plant
W:\55202\REPORTS\F1\ALS\OU6ROD.EPA
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September. 1995
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base, South Dakota
APPENDIX A
FIGURES
W:\S5202\R£PORTS\FI\ALS\OU6ROD.£P.4 September. 1995
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-------
? « |
2
2 & Z
- «" £
t)
»*i
Q
2 it £
UJ ^
o ^ <
^ < v.
II I II
LJ
h- Z Z
< LJ O
O Q. O
N
WINWOOTA
FIGURE 2-1
AREA LOCATION MAP
ELLSWORTH AFB. SOUTH DAKOTA
PREPARED FOR U.S. ARMY CORPS OF ENGINEERS
\
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in _:
at £
2 g
x I
o> x
o
OU-1
OU-2
OU-3
OU-4
OU-5
OU-6
OU-7
QU-8
OU-9
OU-10
OU-11
OU-12
JOT
0 1200 2400
SCALE IN FEET
LEGEND
OPERABLE UNITS
FIRE PROTECTION TRAINING AREA
LANDFILLS 1 8 6
LANDFILL 2
LANDFILL 3
LANDFILL 4
LANDFILL 5
LOW LEVEL RADIATION WASTE BURIAL AREA
EXPLOSIVE ORDNANCE DISPOSAL AREA a PRAMITOL
OLD AUTO HOBBY SHOP AREA
NORTH HANGAR COMPLEX
BASEWIDE GROUND WATER
HARDFILL N0.1
ELLSWORTH AFB IS 12 MILES EAST OF RAPID CITY,
JUST NORTH OF AND ADJACENT TO BOX ELDER
SOURCE; OU-4 Rl REPORT (EAf 1994) _____
CD
tl *-
LU
< LU
O Q.
FIGURE 2-2
SITE MAP
ELLSWORTH AFB, SOUTH DAKOTA
PREPARED FOR U.S. ARMY CORPS OF ENGINEERS
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PEN T'.8LE= F,\I32I46\TBL\I460U6. TBL
OATE=Thu Aug 24 10:58:03 I99S
Levels = i-4.6-8.iO-6?
Levels = i-63
REFERENCE FILE 02 = f :M32'4S\t»rCvbose\b«£«*fl6«Ofi3rfr ILE 04 = f:\l32l46Merc\bose\bcp\ca2.'C:
Levels = i-63 Levels = '-63
,.^p^,v.:--v 2^^:-X
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EAST-WEST
DBA IMAGE
FIGURE 2-4
OU-6 POTENTIALLY AFFECTED WETLANDS
ELLSWORTH AFB. SOUTH DAKOTA
-------
o Or*i
P £ip
:**
'Ai:
< »- -
- ii
z J^ t
i; 2 5
FinilRP ^R
AREA OF ATTAINMENT
ELLSWORTH AFB. SOUTH DAKOTA
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base. South Dakota
APPENDIX B
RESPONSIVENESS SUMMARY
W:\55202\REPORTStfl\ALS\OL'6ROD.EPA September, 1995
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FINAL Record of Decision Operable Unit 6
Ellsworth Air Force Base. South Dakota
Responsiveness Summary
Remedial Action at Operable Unit Six
^Ellsworth Air Force Base, South Dakota
1. Overview
The United States Air Force (USAF) established a public comment period from July 6, 1995 to August
5,1995 for interested parties to review and comment on remedial alternatives considered and described
in the Proposed Plan for Operable Unit Six (OU-6). 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 7:30 p.m. on July 25,1995 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 the Operable Unit (OU).
The Responsiveness Summary provides a summary of comments and questions received from the
community at the public meeting and during the public comment period as well as the USAF's responses
to public comments.
The Responsiveness Summary is organized into the following sections:
Background on Community Involvement
Summary of Comments and Questions Received During the Public Comment Period and
USAF Responses
Remaining Concerns
2. Background on Community Involvement
On August 30, 1990 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.
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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 1995.
Restoration Advisory Board (RAB). The RAB has been formed to facilitate public
input in the cleanup and meets quarterly. In addition to USAF, EPA, and South Dakota
oversight personnel, the RAB includes community leaders and local representatives from
the surrounding area.
Mailing list. A mailing list of all interested parties in the community is maintained by
EAFB and updated regularly.
Fact sheet. A fact sheet describing the status of the IRP at EAFB was distributed to the
mailing list addressees in 1992.
Open house. An informational meeting on the status of the IRP and other environmental
efforts at EAFB was held on May 6, 1993.
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 July 25,1995 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 action; i.e., what would be done, how it would be done? and what effects the action might
have. 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 II - Comprehensive Response to Specific Technical, Legal and
Miscellaneous Questions
The comments and questions below have been numbered in the order they appear in the written
transcript of the July 25,1995 public meeting.
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Comment 1. Marie Chirrel
Asked if anything could be built or constructed on OU-6 during the 30-year monitoring period.
Response 1: Conditions at the site are subject to a five-year review after the remedial action is
completed to ensure the remedy remains effective. If the remedy remains effective, the
property could potentially be used for some limited activities in the future.
Implementation of institutional controls, as part of the proposed remedy, would ensure
only limited activities would take place at OU-6.
Comment 2. Jan Deming
Asked about the status and purpose of the two stormwater drains
Response 2: The northern-most of the two drains is abandoned and no longer in use. The southerly
drain collects stormwater from areas west of the landfill. This drain line would be
extended farther to the southeast, past the landfill area that would receive additional soil
cover. The drain line would continue to be used and would drain into the existing
drainage swale, which flows to the south and east.
Comment 3. Phyllis Engelman
Stated that the active storm drain line drains water from the fuel-storage area to the west and
toward areas off-Base and to the southeast. Asked if there would be any danger from future fuel
spills.
Response 3: The drain will function in much the same way as it does now after it is extended. If there
is a fuel spill, it is possible but unlikely that spilled material would travel off-Base. It is
more likely to be contained by the Base spill response team and not leave Base property.
Comment 4. Lincoln Crum
Asked if the stormwater would still flow to the east so property to the west would not be
affected.
Response 4: It will still flow to the east as it does now. Nothing that will be done at the landfill would
affect property to the west.
Comment 5. Lincoln Crum
Asked about a possible increase in the amount of soil erosion and about what kind of grass
would be grown there, suggesting newer varieties of wheat grass be considered.
Response 5:
The additional soil cover would be graded, compacted, tilled and seeded so that the area will
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look much the same as it does now. Decisions about what type of grass seed to use will be made
in the near future.
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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