PB96-964414
EPA/ROD/R08-96/126
November 1996
EPA Superfund
Record of Decision:
F.E. Warren Air Force Base,
Operable Unit 3, Nob Hill, Cheyenne, WY
3/13/1996
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RECORD OF DECISION
FOR AN INTERIM ACTION
OPERABLE UNIT 3 - NOB HILL
F. E. WARREN AIR FORCE BASE, WYOMING
FEBRUARY 13, 1996
U. S. AIR FORCE
FINAL DOCUMENT
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TABLE OF CONTENTS
PAGE NO.
DECLARATION FOR THE RECORD OF DECISION
1
1
1
1
2
3
4
5
1.0
2.0
3.0
4.0
5.0
6.0
DECISION
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
SITE NAME AND LOCATION
STATEMENT OF BASIS AND PURPOSE
ASSESSMENT OF THE SITE
DESCRIPTION OF THE SELECTED REMEDY
STATUTORY DETERMINATIONS
SIGNATURE OF AGENCY ACCEPTANCE (EPA)
SIGNATURE OF AGENCY ACCEPTANCE (WDEQ)
SIGNATURE OF AGENCY ACCEPTANCE (USAF)
SUMMARY FOR THE RECORD OF DECISION
SITE NAME, LOCATION AND DESCRIPTION
SITE HISTORY AND ENFORCEMENT ACTIVITIES
HIGHLIGHTS OF COMMUNITY PARTICIPATION
SCOPE AND ROLE OF OPERABLE UNIT
SITE CHARACTERISTICS
SUMMARY OF SITE RISKS
DESCRIPTION OF ALTERNATIVES
SUMMARY OF COMPARATIVE ANALYSIS
DESCRIPTION OF SELECTED REMEDY
STATUTORY DETERMINATIONS
EXPLANATION OF SIGNIFICANT CHANGES
1
1
3
3
4
6
7
8
10
11
11
RESPONSIVENESS SUMMARY
INTRODUCTION 1
A. OVERVIEW 1
B. BACKGROUND ON COMMUNITY INVOLVEMENT 1
C. SUMMARY OF COMMENTS RECEIVED 2
D. STATE CONCERNS 2
ATTACHMENT A, COMMUNITY RELATIONS ACTIVITIES
APPENDIX A, FEDERAL AND WYOMING STATE ARARs
FIGURES
Figure 1 F. E. WARREN AFB 2
Figure 2 LOCATION OF LANDFILL 3 AND NOB HILL 5
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DECLARATION FOR THE RECORD OF DECISION
INTERIM ACTION
OPERABLE UNIT 3 - NOB HILL
1.0 SITE NAME AND LOCATION
F. E. Warren Air Force Base
Cheyenne, Wyoming
2.0 STATEMENT OF BASIS AND PURPOSE
The selected interim action (remedy) for Operable Unit 3 (OU3), Nob Hill,
at F.E. Warren Air Force Base (Base), in Cheyenne, Wyoming is the PROVISION OF
AN ALTERNATE WATER SUPPLY BY THE CONSTRUCTION OF A RESIDENTIAL WATER LINE. The
selected action was chosen in accordance with the Comprehensive Environmental
Response, Compensation and Liability Act (CERCLA), as amended by the Superfund
Amendments and Reauthorization Act of 1986 (SARA) , and the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP). The interim action will
ensure a safe, permanent drinking water supply for the Nob Hill community. The
remedy addresses exposure to contaminated ground water in the Nob Hill area.
Remediation of Landfill 3 and contaminated ground water associated with
Operable Unit 3 will be addressed under separate records of decision (RODs).
The decision for the Nob Hill portion of OU3 is based on the Administrative
Record for the site. The United States Environmental Protection Agency (EPA),
and State of Wyoming Department of Environmental Quality (WDEQ), serving as
oversight agencies, concur with the selected remedy. The United States Air
Force (USAF) is the lead agency for the site.
3.0 ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the remedy selected in this Record
of Decision (ROD), may present a current or potential threat to public
health, welfare, or the environment.
4.0 DESCRIPTION OF SELECTED REMEDY
The selected remedy for Nob Hill involves including the Nob Hill
residential area within City of Cheyenne's water supply system. This
remedy involves expanding the City of Cheyenne's current water supply
system by constructing a water supply line to the Nob Hill area,
permitting the residents of Nob Hill access to an alternate water supply.
This remedy for Nob Hill is considered final and supplants the current
action of supplying the Nob Hill residents with bottled water. The
remedy described above is specific to the Nob Hill portion of OU3;
remedies selected for the remaining portions of OU3 (Landfills 3 and 6)
will be described under separate RODs for OU3.
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5.0 STATUTORY DETERMINATIONS
The USAF has determined, with the concurrence of the EPA and the
WDEQ, that the final remedy selected for Nob Hill is protective of human
health, complies with Federal and State applicable or relevant and
appropriate requirements (ARARs) directly associated with this action,
and is cost-effective. This action of providing an alternate water
supply utilizes permanent solutions to the maximum extent practical for
this site. This remedy does not satisfy the statutory preference for
remedies that employ treatment that reduces toxicity, mobility, or volume
as a principal element of the remedy. However, treatment of ground
water, and remediation of Landfill 3, will be addressed in subsequent
actions which will be taken at Operable Unit 3.
CERCLA Section 121(c), 42 U.S.C. Section 9621(c), requires
five-year reviews in the event that hazardous substances, pollutants or
contaminants remain on site. The USAF will conduct reviews every five
years after issuance of this ROD.
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6.0 SIGNATURE OF AGENCY ACCEPTANCE OF REMEDY (EPA)
The undersigned representative concurs with the remedy selected within
this Record of Decision for Operable Unit 3, Nob Hill at F. E. Warren
AFB, Wyoming.
WILLIAM P. YElliOWTAIL Date
ADMINISTRATOR,EPA REGION VIII
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6.0 SIGNATURE OF AGENCY ACCEPTANCE OF REMEDY (WDEQ)
The undersigned representative concurs with the remedy selected within
this Record of Decision for Operable Unit 3, Nob Hill at F. E. Warren
AFB, Wyoming.
DEMNIS HEMMER ^^
Director
Wyoming Department of Environmental Quality
Date
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6.0 SIGNATURE OF AGENCY ACCEPTANCE OF REMEDY (USAF)
The undersigned representative concurs with the remedy selected within
this Record of Decision for Operable Unit 3, Nob Hill at F. E. Warren
AFB, Wyoming.
2 8 FEB 1356
\TRICK P. CARUANA, LT. GEN., USAF Date
Vice Commander, Air Force Space Command
Peterson AFB CO
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DECISION SUMMARY FOR THE RECORD OF DECISION
INTERIM REMEDY
OPERABLE UNIT 3 - NOB HILL
1.0 SITE NAME, LOCATION, AND DESCRIPTION
F. E. Warren Air Force Base (the Base), occupies approximately 5,866
acres immediately adjacent to the west side of the City of Cheyenne, Wyoming
(Figure 1).
The Base was placed on the National Priorities List on February 21, 1990.
Historically, the Base has served a number of military functions, including;
cavalry outpost, quartermaster depot and intercontinental ballistic missile
operations base. Operations began at the U. S. Army outpost named Fort D. A.
Russell in 1867. The name was changed to Fort F. E. Warren in 1930. The Base
was a major training facility during and after World War II. Fort F. E. Warren
was transferred to the newly formed U. S. Air Force in 1947 and was
subsequently named F. E. Warren Air Force Base. The Base underwent extensive
renovation after World War II. The majority of the Army training facilities
were torn down and not replaced. Construction since that time has centered on
facilities for Air Force operations. Beginning in 1958, F. E. Warren Air
Force Base became a Strategic Air Command base. Since then, F. E. Warren Air
Force Base has served as an operations center for the Atlas Intercontinental
Ballistic Missile (ICBM), followed by the Minuteman I and III and finally, the
Peacekeeper (MX) ICBMs. The Base was part of Air Combat Command from 1992 to
1993, and in July 1993, became part of Space Command.
F. E. Warren Air Force Base is bordered by agricultural land and rural or
suburban residential areas. The Base contains 831 residential housing units
and several unaccompanied personnel housing units (barracks), along with the
services required by residents.
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
OU3 consists of Landfill 3, Landfill 6, and Nob Hill. This ROD discusses
the selected interim action for Nob Hill. Remedial investigation (RI)
activities conducted as part of OU3 identified the off-base.movement of a
ground water contaminant plume originating from the Landfill 3 area. The
contaminant plume was determined to be migrating down-gradient toward the Nob
Hill subdivision.
A search of available records indicated that Landfill 3 was a
trench-and-fill operation from 1941 until 1947, and that hardfill was
deposited at the site after 1947. Some burning probably occurred in Landfill
3 based on the 1992 site reconnaissance which indicated the presence of ash,
cinder, general debris, and construction material at the surface of Landfill
3. The general refuse deposited at Landfill 3 includes waste from the Base
shops. A driver training area was located around the landfill area during
World War II. Construction of Happy Jack Road in 1988-89 involved the area to
the southwest of the landfill, but the landfill itself was not disturbed. A
more detailed description of site characteristics (including contaminants
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RE. WARREN
AIR FORCE BASE
EXPLANATION
APPROXIMATE AREA OF
WEAPONS PRACTICE
RANGES IN OPERABLE
UNIT 7 (March 22, 1994)
4c : LANDFILL AND NUMBER
PRINCIPAL AREAS WHERE THE
SHALLOW ZONE OF THE HIGH
PLAINS AQUIFER IS CONTAM-
INATED BY TRICHLOROETHENE,
1986-94, AND DESIGNATED
TCE PLUMES AND IDENTIFI-
CATION (A-E)~
BOUNDARY OF F.E. WARREN
AIR FORCE BASE
SPILL SITE AND NUMBER
FIRE PROTECTION TRAINING
AREA AND NUMBER
ACID DRY WELLS
@ OPEN BURNING/OPEN
DETONATION AREA
2,500
I
5,000 FEET
500
I I
1,000 1,500 METERS
Figure 1. F.E. Warren Air Force Base, Wyoming.
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detected during the OU3 RI) observed at both Landfill 3 and Nob Hill is
presented in Section 5.0.
On September 26, 1991, a Federal Facility Agreement (FFA) was signed
between the USAF, EPA, and WDEQ. The FFA is required by Section 120 of CERCLA.
The FFA provides the framework for EPA and WDEQ oversight of continuing
remedial investigations at the Base and further identifies USAF investigation
activities and schedules. The USAF submits work plans and reports to EPA and
WDEQ for review and comment, in accordance with the FFA.
3.0 fflGHLIGHTS OF COMMUNITY PARTICIPATION
The USAF has prepared and implemented a community relations plan (CRP) in
accordance with CERCLA requirements, and the FFA. The CRP describes community
involvement activities the USAF will undertake during remedial activities at
the Base. The USAF has followed the requirements of the CRP, including
issuance of periodic fact sheets, holding public meetings, and providing the
opportunity for public comment on the Proposed Plan throughout the OU3
investigation.
The Administrative Record has been established at an on-base location and
the Base maintains an Information Repository at the Laramie County Public
Library. The USAF has prepared and distributed fact sheets to all persons or
groups identified on the CRP mailing list (approximately 600 members). In
addition, the Proposed Plan for the preferred remedy at Nob Hill was briefed
and copies of the plan were passed out to the Restoration Advisory Board on
September 19, 1995.
The announcement of the commencement of the public comment period was
made on October 15, 1995, through advertisements in the Wyoming Tribune-Eagle
and in the Casper Star-Tribune. These advertisements announced and outlined
the public comment period and public meeting time. The public comment period
was scheduled from October 29 to November 27, 1995. Additional announcements
concerning the public meeting and proposed plan were printed in the Wyoming
Tribune-Eagle on 21 October, 31 October and 7 November 1995. An article
appeared in the Base Sentinel Paper on October 20 1995. A public meeting was
held at Cheyenne, Wyoming on November 7, 1995.
The Channel 5 KWGN television station carried a report about the Proposed
Plan for Nob Hill on November 7 1995. KRAE radio carried public meeting
announcements periodically throughout this time period.
Responses to all comments on the Proposed Plan are presented in the
Responsiveness Summary attached at the end of this ROD.
4.0 SCOPE AND ROLE OF OPERABLE UNIT
F. E. Warren Air Force Base has been divided into ten operable units.
Besides OU3, the other OUs include the following: OUl-Spill Sites 1 through 7;
OU2-Facility Ground Water; OU4-Acid Dry Wells; OU5-Fire Protection Training
Area 2; OU6-Open Burning/Open Detonation Area; OU7-Firing Range(s); OU8-
Landfill 5; OU9-Landfills 2 and 4; and OUlO-Landfill 7 and Fire Protection
Training Area 1.
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The ground water contamination associated with OUs 3, 6, 7, and 8 will be
investigated and remediated as part of their respective OUs, separate from OU2.
All of the investigations are being conducted in accordance with the FFA.
5.0 SITE CHARACTERISTICS
As described in Section 2.0, leachate originating from the Landfill 3
area is the source of the ground water contaminant plume which has reached the
Nob Hill residential area. The Landfill 3 plume was identified as containing
trichloroethylene (TCE), which is a suspected carcinogen.
No specific characterization has been performed for the Landfill 3
contents. Based on the EPA guidance on presumptive remedies for landfills,
the source of contamination is considered to be the entire landfill area. As
a result, this section will provide a brief summary of the site characteristics
of Landfill 3 as well as the contaminants observed at both Landfill 3 and Nob
Hill ground water monitoring wells.
Landfill 3 is a single area covering approximately 7 acres which is
located near the southeastern boundary of the Base, north of Happy Jack Road
and northwest of the Nob Hill area (Figure 2) . Workshop, domestic, and
construction wastes were disposed of here. Burning probably occurred in the
area as a means to reduce waste volumes. The volume of Landfill 3 is estimated
at 15,400,000 cubic feet but the exact depth and area of the landfill are
unknown. Depth to the water table in this area ranges from 12 to about 38 feet
below ground surface. The landfill has a soil and sparse native grass cover.
Leaching of contaminants from a landfill into the ground water and/or
having landfill contents in contact with the ground water are the primary
release mechanism for landfill contaminant movement. Leachate originating
from the landfill may occur as the result of rain water infiltration and
reaction with landfill contents, or from the movement of liquid waste from the
landfill to ground water. Also, the contents of the landfill may be in direct
contact with the ground water. Investigations are continuing to determine
this. As the leachate is mixed and dispersed through ground water transport,
contaminants may undergo degradation and transformation reactions producing
additional ground water contaminants. The movement of ground water transports
contaminants away from the landfill toward potential receptors such as the Nob
Hill residents.
As part of the OU3 RI field investigations, samples were collected from
Landfill 3 ground water monitoring wells. A ground water sample collected
from an on-base monitoring well located 100 feet up-gradient of the Nob Hill
area was found to be contaminated with TCE at a concentration of 8.8 parts per
billion (ppb). Analysis of a test well nearer the boundary of the Nob Hill
area showed TCE at 2.2 ppb. The maximum contaminant level (MCL) for TCE is 5
ppb. The MCL is the maximum permissible contaminant level for a public water
supply system as defined by the Safe Drinking Water Act.
Due to the potential for off-base movement of the Landfill 3 ground
water contaminant plume, the USAF proposed a ground water sampling program to
ascertain the quality of the water supplied by private wells in the Nob Hill
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subdivision. The Nob Hill subdivision is a triangular shaped residential area
located immediately adjacent to Base property (Figure 2). The Nob Hill
subdivision consists of 16 residences, 11 of which have private wells as their
drinking water source. All of the wells in the area except one were sampled
by the Air Force during the OU3 RI.
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E586.000
104'51'ic
E587.500
104* 50'50"
4 f 08' tO" -
N171.000
41'08' -
N 170.000 -
HEIGHTS
230 HOUSING
200 METERS
too
APPROXIMATE UNDFILL BOUNDARY
APPROXIMATE TRICHLOROETHENE PLUME
BOUNDARY—Boundary where shallow
zone of high plains aquifer Is
contaminated by trtchloroethent at
concentration equal to or grater than
1 microgram per liter
GENERALIZED GROUND-WATER FLOW
DIRECTION
F.E. WARREN AIR FORCE BASE BOUNDARY
D
EXPLANATION
MONITOR WELL AND NUMBER
SITE OF FORMER RESIDENCE WHICH
NO LONGER EXISTS
WELL AT 1929 CARLIN AVENUE USED
FOR IRRIGATION ONLY. DRINKING
WATER SUPPLIED BY WELL AT
4106 STATE STREET
RESIDENCE WITH A WELU WITHOUT
FUNCTIONING PUMP. VOLATILE
ORGANIC COMPOUNDS SAMPLE
COLLECTED
RESIDENCE WITH A WELL NOT
SAMPLED, UNABLE TO OBTAIN
PERMISSION OF OWNER
RESIDENCES SHARING WATER
SUPPLIED BY A SINGLE WELL
RESIDENCE WITH A WELL FROM
WHICH WATER SAMPLES
COLLECTED FOR COMPLETE
LABORATORY ANALYSIS
RESIDENCE WHERE INHABITANTS ARE
USING WELL WATER FOR DRINKING
Figure 2 -r-Locatlon of landfill 3f F.E. Warren Air Force Base, Wyoming,
and Nob Hill area, Laramle County, Wyoming.
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During April, 1994 the USAF initiated sampling of the Nob Hill water
wells and began providing bottled water to the residents of the Nob Hill
subdivision. Analysis of water samples from the Nob Hill water wells
indicated the presence of contaminants including tetrachloroethylene (PCE),
thallium, and nitrates at concentrations in excess of their respective federal
drinking water standards. The April 1994 analysis showed maximum
concentrations of PCE at 11.0 ppb (with a MCL of 5.0 ppb), thallium at
160.0 ppb (MCL =2.0 ppb), and nitrates at 36.9 parts per million (ppm)
(MCL = 10.0 ppm). In addition, TCE was detected in the ground water samples
at a maximum concentration of 2.2 ppb (MCL = 5.0 ppb). The well with the
maximum TCE concentration had an inoperative pump during an initial sampling
effort and was sampled only for volatile organic compounds (instead of the
full analytical suite proposed during this sampling effort). This well was
subsequently re-sampled and analyzed for the full suite. Analysis of this
latter sample showed TCE at 2.2 ppb, while PCE was detected at 130 ppb.
A complete listing of all constituents tested for and the contaminant(s)
concentrations observed at Nob Hill can be found in the Focused Remedial
Investigation Report for OU3, Landfill 3 (August 21, 1994). This report is
located in the Administrative Record on Base as well as the Information
Repository at the Laramie County Library.
6.0 SUMMARY OF SITE RISKS
A streamlined risk assessment (SRA) was performed as part of the OU3,
Landfill 3 and Nob Hill RI to determine the potential human and ecological
exposures and risks from chemicals under baseline conditions. However, the
remedy proposed within this ROD is designed to address the risk to human
health associated with exposure to ground water for the Nob Hill residents.
Indicator contaminants of concern (ICOCs) for ground water identified in the
SRA consist of aluminum, barium, chromium, manganese, nitrate, chloroform,
cis-1,2-dichloroethene and TCE, as determined from on-base well data.
Landfill 3 is the source of several contaminants found at concentrations
that exceed their respective Federal drinking water standard (see Section
5.0). The most prevalent is TCE, considered to be a suspected carcinogen.
The carcinogenic risk from exposure to TCE in ground water is within or
exceeds the target risk range of 10"4 to 10"6 (1 in 10,000 to 1 in 1,000,000).
Most of the non-carcinogenic ground water contaminants were observed at
concentrations that produced a hazard index (HI) well below the action level
of 1.0. The HI calculated for the non-carcinogenic chemicals observed within
monitor well 236 (about 500 feet north-east of the boundary of Nob Hill) was
3.4. The manganese concentration observed in this ground water sample was the
major contributing factor to the elevated HI. The next highest HI was
calculated at monitor well 207 (0.9).
The EPA performed an abbreviated human health risk assessment (AHHRA) in
1994 based on ground water data obtained from the Nob Hill residential wells.
The AHHRA listed chemicals of potential concern for ground water that
included: aluminum, antimony, arsenic, barium, beryllium, cadmium, copper,
lead, nickel, nitrate, selenium, thallium nitrate, vanadium, 2-butoxy-ethanol,
dichlorodifluoromethane, 1,2-dichloroethane, 1,1-dichloroethane, heptachlor
FINALROD.DOC : 2/15/96
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epoxide, methylene chloride, 1,1,1-trichloroethane, TCE, and PCE. Exposure
pathways that were considered in the AHHRA included: ingestion of ground
water; dermal contact with ground water while showering; inhalation of
volatiles from water use; inhalation of volatiles from the ground water
through soils; and ingestion of vegetables and fruits irrigated with the
ground water.
The AHHRA calculated that the carcinogenic risks derived from exposure
to the ground water chemicals of potential concern listed above ranged from
1.7 x 10"6 to 1.8 x 10"4 , which indicates that the total carcinogenic risks
may be within or exceed the target risk range of 10~4 to 10~6. While there was
no single significant chemical that produced an unacceptable risk, arsenic,
beryllium, 1,1-dichloroethane, and PCE all contributed accumulative factors.
All but one non-carcinogenic HI calculated within the AHHRA were below the
action level of 1.0. Thallium concentrations raised the HI to 49.0 at this
residence. The next highest HI was 0.77.
The selected remedy for Nob Hill will reduce the potential risks created
through exposure to the contaminated ground water emanating from Landfill 3 by
eliminating the potential exposure pathways (ingestion, inhalation, dermal
contact, etc.) associated with the ground water contaminants. Exposure to the
hazardous substances within the ground water specific to Nob Hill, if not
addressed, may present a current or potential threat to human health.
7.0 DESCRIPTION OF ALTERNATIVES
Three alternatives were evaluated within the Focused Feasibility Study
prepared for the OU3, Landfill 3, residential water wells (Nob Hill). All
three alternatives are summarized in this section. One of these alternatives
is expected to be the final remedy selected for Nob Hill and will thus be
incorporated within the final remedy selected for OU3.
Alternative 1 is no action. Consideration of the no action alternative
is required by the National Oil and Hazardous Substances Pollution Contingency
Plan. The no action alternative requires no further remediation beyond that
which has previously been accomplished or that which is currently underway
(bottled water deliveries began in April 1994 and are continuing). Ground
water monitoring activities of the private water supply wells in the Nob Hill
subdivision would be performed annually along with the continued delivery of
bottled water under this alternative.
Alternative 2 involves connecting the Nob Hill residences to the City of
Cheyenne municipal water supply (CCMWS) system. Potable water is available
from the CCMWS system by tapping a nearby city water transmission main. This
alternative would be effective in preventing exposure through ingestion of
contaminated water. Additionally, this alternative would be effective in
preventing exposure through inhalation of vapors or dermal absorption during
showering and other household uses. Connection of Nob Hill residences to the
municipal water supply is readily implemented and would provide long term
effectiveness in protecting human health.
Alternative 3 involves the installation of individual filtration treatment
units to each private water supply well in the Nob Hill subdivision. Carbon
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filtration, in addition to other treatment units if necessary, would be
effective in preventing exposure to TCE, PCE, and nitrates which have been
detected to date in the private residential water wells. Installation of
individual home treatment units would be a readily implemented technology.
Regular monitoring of the effectiveness of the units would be required to
ensure protection against exposure to contaminated water. The filtration and
processing units would require periodic replacement.
8.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
Alternatives 2 and 3 are protective of human health because they minimize
the potential risks associated with exposure to contaminated ground water.
Compliance with Federal and State ARARs directly associated with the
technologies employed with Alternatives 2 and 3 will be assured.
Each of the alternatives has been evaluated against the nine criteria
established in the NCP for conducting RI/FS activities under CERCLA to provide
a basis for comparison. The results of this comparative analysis are
summarized below.
1. Overall Protection of Human Health and the Environment: Alternative 1, (No
Action) does not provide protection to residents whose potable water comes
from private wells. Although drinking water is being provided, exposure could
still occur from domestic uses (i.e. bathing or cooking)through both dermal or
inhalation pathways. Under Alternative 1, Nob Hill residents would be exposed
to contaminated ground water which would potentially result in unacceptable
cancer and non-cancer risks. The provision of bottled water will stop once
the proposed interim action is in place. Alternative 2, (water line) would
provide water from a system which complies with federal drinking water
standards. As such, this alternative would be protective of human health.
Alternative 3 (Home treatment units/filters) would protect residents from
exposure to contaminated ground water.
2. Compliance with ARARs: Under Alternative 1, residents using private water
wells in the Nob Hill subdivision would be exposed to contaminated ground
water exceeding ARARs (federal drinking water standards). Since the City of
Cheyenne municipal water supply is subject to compliance monitoring, using
Alternative 2 would result in Nob Hill residents being provided with water
which meets ARARs (Federal Drinking Water Standards). Alternative 3 would also
comply with federal drinking water standards by removing the contaminants via
tap filters. Alternative 2 will meet the ARARs identified in Appendix A, but
not other ARARs identified in the Feasibility Study relating to remediation of
the ground water contamination or soil contamination that may cause ground
water contamination. Because this action is off-site, all required permits
for the construction of the water line will be obtained.
3. Long-Term Effectiveness and Permanence: Alternative 1 does not provide a
long term effective solution to the potential risks posed by the contaminated
ground water emanating from Landfill 3. Alternative 2 is considered to be a
permanent remedy. After connection of the Nob Hill residences to the CCMWS,
exposure to contaminated ground water in the residences would be eliminated.
Alternative 3 is not considered a permanent remedial action since replacement
of the carbon filters would be required on a periodic basis.
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4. Reduction of Toxicity, Mobility, and Volume Through Treatment: This
criterion is not addressed by alternatives one and two which were evaluated
under the feasibility study for OU3, Landfill 3 Residential Wells (Nob Hill).
Alternative 3 (filtration and water treatment)does treat the ground water in
the water wells but does nothing to remediate the ground water plume
originating from Landfill 3. The remedy selected for containment and/or
treatment of the contaminated ground water plume at OU3, Landfill 3 will be
documented within the OU3, Landfill 3 ROD.
5. Short-Term Effectiveness: Alternative 1 would have no short-term impacts
to the surrounding community or workers associated with the remedial action
since no action is taken. However, Alternative 1 would result in continued
exposure of Nob Hill residents to contaminated ground water. No exposure of
workers, residents, or the environment to ground water contaminants would
occur as a result of construction of the water line described under
Alternative 2. Once initiated, Alternative 2 could be completed within a
relatively short period of time (projected completion within 60 days). Under
Alternative 3, a possibility exists of worker exposure to ground water
contaminants during installation of the filter units. This exposure would be
limited to very brief periods of dermal exposure and vapor inhalation from the
ground water. It is anticipated that treatment units (Alternative 3) could be
installed for each of the sixteen residences within a 60 day time-frame.
6. Implementability: Alternative 1, which would include a long-term ground
water monitoring effort of the private residential water wells, is readily
implemented. The activities associated with Alternatives 2 and 3 are
routinely accomplished. Materials, equipment and services associated with
these alternatives are readily available. These alternatives are technically
and administratively feasible.
7. Cost: There are no capital costs associated with Alternative 1. Annual
ground water monitoring costs anticipated under Alternative 1 are estimated to
be approximately $20,000 for the 16 residences of Nob Hill. For a 30 year
project life and an assumed interest rate of 5 percent, the total present
worth cost associated with this alternative is approximately $310,000.
The estimated total capital expenditure for Alternative 2, including the
design and construction of the proposed water line, is approximately $366,000.
In addition, the USAF will pay the hook up costs, estimated at $1,000 per
household, for a total capital cost of $382,000. No operation and maintenance
(O&M) costs are associated with this alternative.
Capital costs estimated for implementation of Alternative 3, including
labor and material, is estimated at approximately $2,000 per household. This
results in a total capital cost of $32,000 for 16 homes in the Nob Hill
subdivision.
Alternative 3 would involve O&M costs associated with replacement and
maintenance of the filters. The estimated cost for each filter is $300, which
includes installation. Assuming the filters require replacement three times
per year, the annual O&M cost per household is estimated at $900. The total
O&M cost for the entire Nob Hill subdivision is estimated at $14,400 per year.
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An additional O&M cost which would be incurred under Alternative 3 involves
periodic monitoring of the filtered water to verify the effectiveness of
filtration. Annual monitoring costs for the entire Nob Hill subdivision is
estimated to be an additional $20,000, bringing the total annual O&M costs
under Alternative 3 at $34,400.
The total net present cost associated with Alternative 3 is estimated to
be $560,000. This estimate uses an assumed project life of 30 years and a
assumed interest rate of 5 percent.
8. State Acceptance: The State of Wyoming has indicated support of
Alternative 2, connection to City of Cheyenne's municipal water supply. It is
unknown whether the State would accept the individual treatment unit option.
It is doubtful that the State would accept Alternative 1..
9. Community Acceptance: Community acceptance of Alternative 2 has been
mixed, as based on past experiences at community meetings held to discuss the
alternatives in question. A survey of the residents in April 1995 revealed
that about half do want to be hooked up to city water. The other half either
did not respond to the survey or stated they did not want to be hooked up to
city water. The main reason expressed by those residents that did not want to
be hooked up to the CCMWS involved a clause in the city's standard agreement
for providing water service to out of town residents. This clause prevents
residents located outside of the city limits and yet whose potable water was
supplied by the CCMWS from fighting future annexation plans proposed by the
city.
After further discussions and neighborhood meetings, the Nob Hill
residents agreed to the remedy prescribed under Alternative 2. All of the Nob
Hill residents signed a petition supporting the water line project following
the August 31, 1995 neighborhood meeting.
Community acceptance of Alternative 3 (filtration) is unknown.
Community acceptance of Alternative 1 is unlikely.
9.0 DESCRIPTION OF SELECTED REMEDY
The selected remedy for Nob Hill involves including the Nob Hill
residential area within the City of Cheyenne's water supply system. This
remedy involves expanding the City of Cheyenne's current water supply system
by constructing a water supply line to the Nob Hill area, permitting the
residents of Nob Hill access to an alternate water supply. Since the City of
Cheyenne municipal water supply is subject to compliance monitoring, this
remedy results in Nob Hill residents being provided with water which meets the
ARARs for this action - Federal drinking water standards (Appendix A). Also,
because this is an off-site action all required permits for the construction
of a water line will be obtained. This remedy will reduce the potential risks
created through exposure to the contaminated ground water emanating from
Landfill 3 by eliminating the potential exposure pathways (ingestion,
inhalation, dermal contact, etc.) associated with the ground water
contaminants.
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The estimated total capital expenditure for this remedy, including
design and construction of the proposed water line, is approximately $366,000.
In addition, the USAF will pay the hook up costs, estimated at $1,000 per
household, for a total capital cost of $382,000. No operation and maintenance
(O&M) costs are associated with this alternative.
This remedy can be completed within a relatively short period of time
(projected completion within 60 days of commencement of construction.
10.0 STATUTORY DETERMINATIONS
The USAF's selected remedy for Operable Unit 3, Nob Hill is Alternative
2. Remedial actions implemented under this alternative would achieve risk
reduction by limiting exposure to the contaminated ground water by supplying
the residents of Nob Hill with an alternate potable water supply. Alternative
2 is more reliable than Alternative 3 because of the potential for the filters
to fail without proper maintenance. Regulatory water quality controls imposed
on the municipal water supply provides for a more reliable potable water supply
to the residents of Nob Hill. Based on the information available at this time,
the USAF believes the preferred alternative will be protective of human health
and will comply with ARARs.
The preferred alternative described above is intended to address the
potential human health risks associated with exposure to contaminated ground
water from using private drinking water wells. This interim remedy does not
address the remediation of the ground water plume associated with Landfill 3.
The final remedy selected for containment and treatment of the contaminated
ground water media at Landfill 3 will be documented within the Landfill 3 ROD.
11.0 EXPLANATION OF SIGNIFICANT CHANGES
The Proposed Plan was released for public comment on October 15, 1995. The
preferred alternative was Alternative 2, where the construction of a water line
would provide the Nob Hill residents with a safe, long term water supply. The
USAF, EPA, and WDEQ reviewed all written and verbal comments submitted during
the public comment period. It was determined that no significant changes were
necessary to the preferred alternative described in the Proposed Plan.
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RESPONSIVENESS SUMMARY
RECORD OF DECISION
OPERABLE UNIT 3
LANDFILL 3; NOB HILL
INTRODUCTION
The responsiveness summary is organized into sections as follows:
A. Overview
B. Background on Community Involvement
C. Summary of Comments Received
D. State Concerns
E. Attachment: Community Relations Activities at F.E. Warren Air
Force Base.
A. OVERVIEW
At the time of the public comment period, the preferred alternative for
the remedial action at Nob Hill, Operable Unit 3, at F. E. Warren Air Force
Base, included the provision of an alternate water supply to the residents of
Nob Hill via the construction of a municipal water main to the subdivision.
This remedial action had been selected by the USAF, with EPA and WDEQ
concurrence and was presented in the Proposed Plan. Based on the public's
response and comments received during the public comment period, there are no
objections to the preferred alternative.
B. BACKGROUND ON COMMUNITY INVOLVEMENT
Community interest in CERCLA/IRP (Installation Restoration Program)
activities at F. E. Warren Air Force Base has varied over the years since the
records search and interviews conducted by Engineering Science for the USAF in
September 1985. No specific individuals or representatives from organizations
have been consistently involved over this period, although numerous groups and
persons have been involved from time to time. There is an extensive history of
public comment and discussion by the Nob Hill residents, Air Force, EPA, WDEQ
and the City of Cheyenne.
The first neighborhood meeting was held with the Nob Hill residents in
April 1994 after the USAF discovered the possibility of contaminants reaching
the Nob Hill wells. Delivery of bottled water and sampling of the residential
water wells began immediately after that meeting. Discussions concerning the
proposed water line began in the fall of 1994 with a neighborhood meeting
conducted in November 1994. The water line was not accepted by the Nob Hill
residents at that time due to the language in the City of Cheyenne's users
agreement. This agreement stipulated that any users outside of the city
limits, which pertains to Nob Hill, must pay one and a half the standard water
users fee and agree to not fight annexation, if proposed, of the neighborhood.
Most of the Nob Hill residents did not want to sign this agreement.
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Another meeting with the Nob Hill residents in May 1995 still did not
resolve the annexation issue. A survey was distributed to the residents in
April 1995 to determine their opinions and thoughts on the water line. All
eight residents which responded to the survey said they were not interested in
a water line if the annexation clause remained in the water users agreement.
The Air Force asked the City Council to consider waiving the annexation part of
the users agreement. This proposal was presented for a vote to the City Council
in June of 1995 and was defeated.
Another neighborhood meeting, hosted by the WDEQ, was held on August 31,
1995 and the residents were once again briefed on the situation.
Representatives from several different agencies spoke including the WDEQ,
Laramie County and the City of Cheyenne. At this meeting, the Nob Hill
residents agreed to the water line and the standard users agreement, including
the annexation clause. A petition asking for confirmation of the acceptance of
the water line was circulated in September 1995 by the Air Force. All of the
Nob Hill residents signed it, thus clearing the way for the Air Force to begin
the water line project.
Up to the current date, there have been four neighborhood meetings,
approximately 20 newspaper articles, and numerous television and radio stories
broadcast that concerned the Nob Hill water line.
C. SUMMARY OF COMMENTS RECEIVED
The public comment period on the Proposed Plan for Landfill 3; Nob Hill
remedial action, at F. E. Warren Air Force Base was held from October 29 to
November 27, 1995. No comments were sent in. The only comments received during
the public meeting held on November 7, 1995 dealt with the actual location of
the waterline. This information will not be available until the design is
completed. Also, a question of when the waterline would be completed was
asked. The waterline should be completed by summer 1996.
As mentioned above, a survey of the residents was distributed in April
1995. Eight of the residents responded to the survey and all eight said they
did not want the water line if they had to sign the agreement with the
annexation clause. Three of the responses said they would like to be hooked up
to the water line if the annexation clause was waived. The other six did not
want to be hooked up even if the clause was waived.
Following the August 31, 1995 meeting, a petition was distributed to the
Nob Hill residents asking for signatures supporting the construction of a water
line under the terms of the standard water users agreement (with the annexation
clause) . All 14 of the residents currently in Nob Hill signed the petition.
D. STATE CONCERNS
The following are the comments received by the Wyoming Department of
Environmental Quality:
As a party to the FFA, the State of Wyoming has been involved in
ground water investigations and screening of potential remedial
alternatives for implementation at Nob Hill throughout the process. The
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state has indicated its support for the installation of the water line,
which will connect the Nob Hill residences to the City of Cheyenne's
water supply system, as the most expedient and reliable of available
options to ensure that safe water is accessible to the people living in
the Nob Hill area.
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ATTACHMENT A
COMMUNITY RELATIONS ACTIVITIES
At
F.E. WARREN AIR FORCE BASE
OVERVIEW
The unique community involvement needs of F. E. Warren Air Force Base
IRP/CERCLA activities are addressed in the Community Relations Plan (CRP) . In
late 1990, during plan development, interviews were held with 56 people
representing F. E. Warren Air Force Base, other Federal agencies, State, city
and county agencies, community groups, well owners, and other individuals. The
most significant issues identified in the interviews were concerns about
potential drinking water contamination and about the community involvement
process.
ADMINISTRATIVE RECORD and INFORMATION REPOSITORY
An Information Repository and an Administrative Record containing
documentation of the IRP/CERCLA process were established in October 1989 and
are maintained at the following locations to insure accessibility.
Information Repository Administrative Record
Laramie County Library 90 CES/CEVR
Reference Section Environmental Restoration Section
2800 Central Avenue 300 Vesle Drive
Cheyenne WY 82001 F. E. Warren AFB WY 82005-2788
Phone (307) 634-3561 Phone (307) 775-3468
These records are maintained according to EPA guidelines, by the
Environmental Restoration Flight, and are updated at least quarterly.
MAILING LIST
A major part of the public relations activities is the mailing list. In
an attempt to proactively contact the 2,300 well owners identified in the EPA
Superfund hazard ranking package submitted for the Base, the USAF sent a
general mailing to well owners within a 3-mile radius. The Wyoming State
Engineer's Office provided the mailing list of well owners. The mailing
included a brief status report and a coupon to be mailed back if the well owner
wanted to be added to the mailing list for distribution of later status
reports. This activity resulted in the current list that has about 600 names
on it. The mailing list is maintained in the F. E. Warren Air Force Base
Public Affairs Office. Status Reports or Fact Sheets are mailed on a quarterly
basis. Anyone who desires to be included on the list should contact either of
the following offices.
90 CES/CEVP 90 CES/CEVR
300 Vesle Dr., Suite 600 300 Vesle Drive
F. E. Warren AFB WY 82005-2788 F. E. Warren AFB WY 82005-2788
Phone (307) 775-4154 Phone (307) 775-3468
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INFORMATION CONTACT
An information contact person has been designated within the F. E. Warren
Air Force Base Environmental Restoration Section to maintain regular contact
with the community. This person will be responsible for responding to requests
for information and planning and scheduling activities included in the plan.
The preparation of materials for public distribution will be coordinated with
the Public Affairs Office. General public information requests should be
directed to (307) 775-3468. The media contact for F. E. Warren Air Force Base
is the Environmental Public Affairs office at (307) 775-4154.
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Appendix A
Federal and Wyoming State
Applicable, or Relevant and Appropriate Requirements (ARARs)
For Nob Hill Interim Action at F.E. Warren AFB
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Table A-l - Federal Chemical-Specific ARARs
[USC, United States Code; CFR, Code of Federal Regulations; Statute; Exec., Executive; DOT, Department of Transportation; FS, Feasibility Study]
Standard requirement, Citations Description Applicable/ Comments
criteria, or limitation Relevant and
Appropriate
Safe Drinking Water Act 42 USC 300g
National Primary Drinking-Water Regulations 40 CFR 141, Establish health based standards for the public No/Yes Groundwater is a potential or actual source of
Subparts B and G water systems (maximum contaminant levels) drinking water. This interim action is due to
groundwater contamination. The cleanup of
ground water will be addressed in subsequent
actions
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