PB97-964606
EPA/541/R-97/050
November 1997
EPA Superfund
Record of Decision:
Elmendorf Air Force Base,
Operable Unit 3,
Greater Anchorage Borough, AK
12/5/1996
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UNITED STATES AIR FORCE
ELMENDORF AIR FORCE BASE, ALASKA
ENVIRONMENTAL RESTORATION PROGRAM
OPERABLE UNIT 3
RECORD OF DECISION
FINAL
JANUARY 1997
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DCN 97-269-109-12
RCN F33615-90-D-40J3 DO 0009
UNITED STATES AIR FORCE
ELMENDORF AIR FORCE BASE, ALASKA
ENVIRONMENTAL RESTORATION PROGRAM
OPERABLE UNIT 3
RECORD OF DECISION
FINAL
JANUARY 1997
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TABLE OF CONTENTS
Page
PART I. DECLARATION I-i
PART II. DECISION SUMMARY Il-i
1.0 SITE NAME, LOCATION, AND DESCRIPTION 1-1
1.1 Physical Description 1-1
1.2 Land Use 1-4
1.3 Hydrogeology and Groundwater Use 1-4
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 2-1
2.1 Identification of Activities Leading to Current Contamination at OU 3 2-1
2.2 Regulatory and Enforcement History 2-2
2.3 Role of Response Action 2-3
2.4 Community Participation 2-3
3.0 SITE CONTAMINATION, RISKS, AND AREAS REQUIRING RESPONSE
ACTIONS 3-1
3.1 Nature and Extent of Contamination 3-1
3.1.1 Soil and Sediment 3-4
3.1.2 Groundwater 3-9
3.2 Groundwater Modeling 3-10
3.3 Risk Evaluation 3-11
3.4 Summary 3-16
4.0 REMEDIAL ACTION OBJECTIVES, ALTERNATIVES, AND
COMPARATIVE ANALYSIS 4-1
4.1 Contaminants of Concern and Need for Remedial Action 4-1
4.2 Remedial Action Objectives and Goals 4-1
4.3 Alternatives 4-3
4.4 Summary of Comparative Analysis of Alternatives 4-5
4.4.1 Threshold Criteria 4-5
4.4.2 Balancing Criteria 4-6
4.4.3 Modifying Criteria 4-6
5.0 SELECTED REMEDY 5-1
5.1 Statutory Determinations 5-2
5.1.1 Protective of Human Health and the Environment 5-2
5.1.2 Applicable or Relevant and Appropriate Requirements (ARARs) 5-2
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TABLE OF CONTENTS (CONTINUED)
Page
5.1.3 Cost Effectiveness 5-2
5.1.4 Utilization of Permanent Solutions and Alternative Treatment
Technologies to the Maximum Extent Practicable 5-3
5.1.5 Preference for Treatment as a Principal Element 5-3
5.2 Documentation of Significant Changes 5-3
PART III. RESPONSIVENESS SUMMARY Hl-i
APPENDIX A: OU 3 Administrative Record Index
APPENDIX B: COPCs in Soil and Groundwater
ACRONYM LIST
11
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LIST OF TABLES
Page
3-1 Summary of Soil Contamination/Cleanup Standards at Operable Unit 3,
Elmendorf AFB, AK 3-5
3-2 Summary of Surface Water and Sediment Contamination/Cleanup Standards
at Operable Unit 3, Elmendorf AFB, AK 3-6
3-3 Summary of Shallow-Aquifer Groundwater Contamination/Cleanup Standards
at Operable Unit 3, Elmendorf AFB, AK 3-10
3-4 Exposure Assumptions for OU 3 , Elmendorf AFB, AK 3-12
3-5 Summary of Health Risks at Operable Unit 3 , Elmendorf AFB, AK 3-14
4-1 Cost and Duration for Remedial Alternatives 4-5
LIST OF FIGURES
Page
1-1 Site Location Map, Elmendorf AFB, AK 1-2
1-2 Location of OU 3 Study Area, Elmendorf AFB, AK 1-3
1-3 Hydrogeologic Conceptual Model 1-5
3-1 Soil Areas of Interest at OU 3, Elmendorf AFB, AK 3-2
3-2 Groundwater Areas of Interest at OU 3, Elmendorf AFB, AK 3-3
3-3 Location of Excavation and Reconstruction at Cherry Hill Ditch
Elmendorf AFB, AK 3-8
4-1 Approximate Location of Impacted Soil at Source Area SS21, Elmendorf AFB, AK 4-2
111
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PARTI.
DECLARATION
SITE NAME AND LOCATION
Elmendorf Air Force Base (AFB)
Operable Unit (OU) 3
Elmendorf Air Force Base, Alaska
STATEMENT OF BASIS AND PURPOSE
This Record of Decision (ROD) presents the selected remedial action for OU 3 at Elmendorf
AFB. It was developed in accordance with the Comprehensive Environmental Response, Compensation,
and Liability Act of 1980 (CERCLA) as amended by the Superfund Amendments and Reauthorization
Act of 1986 (SARA), 42 U.S.C. §9601 et seq.. and, to the extent practicable, in accordance with the
National Oil and Hazardous Substances Pollution Contingency Plan (NCR), 40 CFR §300 et seq. The
attached administrative record index (Appendix A) identifies the documents upon which the selection of
the remedial action was based. The U.S. Air Force (USAF), the U.S. Environmental Protection Agency
(USEPA), and the State of Alaska, through the Alaska Department of Environmental Conservation
(ADEC), concur with the selected remedy.
ASSESSMENT OF THE SITE
Contaminant concentrations in OU 3 soil and shallow-aquifer groundwater were compared with
risk-based criteria and interim remediation goals. As a result, the contaminant of concern (COC)
identified at OU 3 is polychlorinated biphenyls (PCBs) at site SS21. Risks for soil at SD31, SD16, and
Cherry Hill Ditch are within an acceptable range and resulted in no further action decisions for the soil at
SD31, SD16, and Cherry Hill Ditch. The risks for groundwater beneath OU 3 are above maximum
contaminant levels (MCLs) however; institutional controls exist at the base for the shallow aquifer and
groundwater monitoring of selected wells located within OU 3 is included as part of OU 5 groundwater
monitoring. Therefore, action is not required for groundwater under this ROD. The institutional control
against use of shallow groundwater at the base is through the Elmendorf Air Force Base Facility Board.
Actual or threatened releases of PCBs from SS21 at OU 3, if not addressed by implementing the
response action selected in this ROD, could present an imminent or substantial endangerment to public
health, welfare, or the environment.
DESCRIPTION OF THE SELECTED REMEDY
The selected remedy was chosen from many alternatives as the best method of addressing the
PCB contaminated soil at site SS21. It addresses the risks to health and the environment caused by the
hypothetical exposure of a future resident to contaminated soils. The selected remedy addresses this risk
by reducing soil contamination to below cleanup levels established for OU 3. The PCB concentrations
found at SS21 are below levels regulated by the Toxic Substances Control Act (TSCA).
The selected remedy is excavation and off-site disposal of soil at SS21 containing PCBs greater
than 5 ppm. The specific components of the selected remedy consist of the following:
January 1997 I-i OU 3 Record of Decision, Final
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To protect human health, a chain link fence will be used to temporarily restrict access to the
contaminated soil at SS21 until the soil has been removed and disposed off-site;
All soil with PCB concentrations in excess of 5 ppm will be excavated and shipped to a disposal
facility in the lower 48 which is acceptable for disposal of CERCLA waste under the Off-Site
Disposal Rule (40 CFR 300.440);
Confirmation sampling will be performed to ensure cleanup goals have been met;
The sampling and removal of PCB soils at SS21 is expected to be accomplished within one field
season; and
After cleanup, site SS21 soil will be available for unrestricted use. As a requirement of
previously signed RODs for Elmendorf Air Force Base, institutional controls have been
established to restrict the use of the shallow aquifer in the outwash plain on the base.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the environment, complies with federal
and state requirements that are legally applicable or relevant and appropriate to remedial action, and is
cost-effective. This remedy utilizes permanent solutions and alternative treatment technologies to the
maximum extent practicable. However, because treatment of the contaminants at the site was not found
to be practicable, this remedy does not satisfy the statutory preference for treatment as a principle
element.
OU 3 Record of Decision, Final I-ii January 1997
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LEAD AGENCY ACCEPTANCE
OF THE RECORD OF DECISION,
ELMENDORF AER FORCE BASE, OPERABLE UNIT 3
This signature sheet documents U.S. Air Force acceptance of the Record of Decision for
Operable Unit 3 at Elmendorf Air Force Base.
EUGENE D. SANTARELLI, Lt Gen, USAF Date
Chairman, HQ PACAF
Environmental Protection Committee
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LEAD AGENCY ACCEPTANCE
OF THE RECORD OF DECISION,
ELMENDORF AIR FORCE BASE, OPERABLE UNIT 3
This signature sheet documents United States Environmental Protection Agency acceptance
of the Record of Decision for Operable Unit 3 at Elmendorf Air Force Base.
CHUCK CLARKE Date
Regional Administrator
Region X
U.S. Environmental Protection Agency
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SUPPORT AGENCY ACCEPTANCE
OF THE RECORD OF DECISION,
ELMENDORF AIR FORCE BASE, OPERABLE UNIT 3
The Alaska Department of Environmental Conservation concurs with the Record of Decision for
Operable Unit 3 at Elmendorf Air Force Base.
r _ ~<^ *
V0' KUTtf FRgDRIKSSON Date
Director, Spill Prevention and Response
Alaska Department of Environmental Conservation
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PART II.
DECISION SUMMARY
This Decision Summary provides an overview of the problems posed by the contaminants at
Elmendorf Air Force Base (AFB) Operable Unit (OU) 3. It identifies the areas considered for remedial
response, describes the remedial alternatives considered, and analyzes those alternatives compared to the
criteria set forth in the National Contingency Plan (NCP). The Decision Summary explains the rationale
for selecting the remedy, and how the remedy satisfies the statutory requirements of the Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA).
January 1997 Il-i OU 3 Record of Decision, Final
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PART III.
RESPONSIVENESS SUMMARY
Public Input into the OU 3 Selected Remedy
The primary avenues of public input have been through the Proposed Plan and public comment
period. The Proposed Plan for OU 3 was issued to the public on June 19, 1995. The public comment
period was from June 20 through July 21, 1995. To encourage public comment, the USAF inserted a
pre-addressed comment form in distributed copies of the Proposed Plan. The comment forms were also
distributed at the July 12, 1995, public meeting, held at the University of Alaska in Anchorage.
The public meeting to receive comments on the Proposed Plan was attended by 37 people,
including 13 representatives from the Restoration Advisory Board (RAB). Oral comments were received
at the meeting. Prior to the conclusion of the public comment period, one written comment was
submitted.
All comments received are documented in the administrative record file for the site. A transcript
of the public meeting is available for public review at the site information repositories. The repositories
are located at the Bureau of Land Management's Alaska Resources Library and the University of Alaska
Anchorage's Consortium Library. Public comments, relevant to OU 3 and / or the environmental
restoration program at Elmendorf AFB, are presented below and have been paraphrased for clarity. This
ROD is based on the documents in the Administrative Record and comments received from the public.
Response to Written Public Comment:
Public Comment: Agreement with the selected alternative of treating the PCB-
contaminated soil at SS21 with bioremediation was expressed in a letter
to the base.
USAF Response: A treatability study performed in 1996 indicated that bioremediation
would not be effective in reducing PCB levels. The selected alternative
is excavation and transportation of soil greater than 5 ppm PCBs to a
USEPA-approved disposal facility.
Response to Oral Public Comments:
Public Comment 1: When the treatability study is performed, are efforts going to be made to
simulate actual field conditions? If so, how will this be done?
USAF Response: Yes, efforts were made to duplicate field conditions. The same soil
types were used. The test was conducted in the lab but did duplicate the
same conditions as in the field (e.g., temperature and soil conditions).
Public Comment 2: How long will the treatability study take?
USAF Response: The treatabiliry test was conducted from February through May of 1996
(approximately 90 days).
January 1997 IH-i OU 3 Record of Decision, Final
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Public Comment 3:
USAF Response:
Public Comment 4:
USAF Response:
Public Comment 5:
USAF Response:
Public Comment 6:
USAF Response:
Public Comment 7:
USAF Response:
Public Comment 8:
USAF Response:
Public Comment 9:
USAF Response:
Public Comment 10:
USAF Response:
Has the technology been tested in Alaska?
Not that we are aware of. This was the first time it was tested for use in
Alaska.
Are you going to try to thermally cycle the treatability like it would be in
its natural, in-situ situation? In other words, long sunlight exposure?
We kept the soil at a constant temperature, the mean average soil
temperature in summer in the Anchorage area. We did not simulate long
sunlight because sunlight is not considered to have a significant impact
on the effectiveness of this technology.
If for some reason bioremediation does not work, where would the soil
be stored if you had to excavate?
The soil will not be stored but will be excavated directly into containers
for shipping.
How deep are the PCBs at a dangerous level or at a level that needs to be
cleaned up?
The average depth is approximately one foot. There are several areas
that are about two-and-a-half feet. One area extends to approximately
four feet.
Will you try to roto-till to that depth?
All of the soil with PCB concentrations above 5 ppm is present in the
top six inches of soil. All of this soil will be removed.
I assume that the bioremediation must take place close to the surface so
that oxygen is present.
The bioremediation process is both aerobic and anaerobic. Therefore,
oxygen needs to be present for part of the life cycle and not for others.
The soil would have been initially disturbed to bring it to the surface and
then left alone for the bio-process to work.
What kinds of temperatures and resident times will be necessary to
thermally treat the soil if the bioremediation does not work?
In order to volatilize the PCBs, it would take 850 to 900 degrees
Fahrenheit. The technology is referred to as thermal desorption.
What is the total volume of contaminated soil?
The total volume of soil with greater than 5 ppm PCBs is 200 cubic
yards.
OU 3 Record of Decision, Final
Ill-ii
January 1997
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Public Comment 11:
USAF Response:
Public Comment 12:
USAF Response:
Public Comment 13:
USAF Response:
Public Comment 14:
USAF Response:
Public Comment 15:
USAF Response:
The Proposed Plan stated that none of the OU 3 sites have large areas of
elevated levels of fuel or solids (solvents?) in the soil. Therefore, the
sites at OU 3 do not appear to be current sources of solvents found in the
groundwater. Is it that the sites are no longer the current source or the
identified sites are not the source? Will there be further contamination
in the groundwater due to additional sources?
The sites investigated at OU 3 are believed to be the former sources of
the contamination identified in the groundwater due to infiltration
through the soil column. The sources have been removed but
contamination remains in the shallow groundwater aquifer. We believe
that there are no current sources of solvent contamination of the
groundwater at OU 3. The shallow-aquifer groundwater will be
monitored in the future (under other Records of Decision) to ensure that
the level of contamination remains low.
It appears that the levels of groundwater contamination are decreasing.
What is the time frame when you will say the contamination is removed
and monitoring is no longer required?
Groundwater modeling performed as a part of the base wide program
indicated that within 10 to 15 years the levels will decrease below any
concern. A basewide program of groundwater monitoring has been
developed to support RODs for OUs 1, 2, 4, and 5. Some wells at OU 3
will be included in this program and will be monitored to ensure that the
levels continue to decrease to acceptable levels. Groundwater
monitoring will not be a part of the OU 3 ROD. It is important to note
that the current contamination levels indicate a risk of less than 10'5.
This is a very low risk. This assumes people are drinking and bathing
with the shallow-aquifer groundwater, when in fact, this is not the case.
The water is not used for any purpose.
You mentioned that the bioremediation is an innovative technology. Is
this something "off the shelf?
The technology has been used effectively in many parts of the world and
had a reasonable chance for success in this instance. Since this
alternative did not work, we will use an alternate method to remediate
the soil.
What sort of levels have been treated with the bioremediation
technology?
Levels of PCBs in the thousands of parts per million have been treated
successfully at other sites.
Is this an active biological treatment or chemical enzyme?
It is an active biological treatment.
January 1997
OU 3 Record of Decision, Final
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Section 1.0
SITE NAME, LOCATION, AND DESCRIPTION
The following subsections describe the physical description, land use, and hydrogeology of
OU 3, as well as groundwater use.
1.1 Physical Description
Elmendorf AFB is located approximately two miles north of downtown Anchorage (Figure 1-1).
It is bordered to the north and west by the Knik Arm, to the east by Fort Richardson Army Post, and the
south by a light industrial area and land owned by the Alaska Railroad Company. The base provides
defense for the United States through surveillance, logistics, and communications support. OU 3 is
located in the southwest quarter of Elmendorf AFB, on relatively flat terrain at an approximate elevation
of 150 feet above sea level. OU 3 consists of three source areas and one receptor area (Figure 1-2). The
source areas include: a former shop waste disposal site (SD16), the former polychlorinated biphenyls
(PCB) transformer storage area (SS21), and a dry well at an aircraft maintenance hangar (SD31). Site
SD52 (Cherry Hill Ditch) is not considered a source of contamination but did receive water runoff from
the eastern portion of the base.
Source Area SD16 - Former Shop Waste Disposal Site
Source SD16 is composed of an open, grassy field north of Building 31-260, south of the west
ramp (Figure 1-2). This source area was a location where waste solvents were disposed in earthen
trenches. Due to regrading and revegetation of part of the source area, the former disposal trenches no
longer exist. The northern portion of this source area serves as a place to stockpile snow during the
winter and the eastern half of SD16 is used for heavy equipment storage.
Source Area SS21 - Former PCB Transformer Storage Area
Source SS21 is the site of former Building 31-357, which served as a storage building for PCB
transformers in the I970's. The site is located north of Nutmeg Boulevard and west of Elm Street
(Figure 1-2). The buildings have been demolished; however, two concrete pads remain. One concrete
pad and the loading dock were removed in 1996 as part of a sampling program.
Cherry Hill Ditch
Cherry Hill Ditch (SD52) is an artificial drainage channel which flows westward from the
east-west runway at Elmendorf AFB toward the Knik Arm of the Cook Inlet. The ditch is used to direct
surface water to the bluff above Knik Arm (Figure 1-2). Downstream of the ditch, a 30-inch pipe
discharges water at approximately 200 gallons per minute. The source of the water carried in the ditch
includes subsurface drains located under the runway and various buildings on the base, and a large
portion of the storm water runoff from the eastern half of the base.
Source SD31 - Hangar 5 Dry Well
Source SD31 is located on the southern part of the base, north of Second Street and east of Elm
Street (Figure 1-2). In the past, floor drains within the building discharged to a dry well located on the
northeast side of the building. This dry well was removed in July 1993 by excavating the well and the
surrounding soil. At present, the site is covered with an asphalt pad.
January 1997 1-1 OU 3 Record of Decision, Final
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Richardson-
Army Po§4~-'
SCALE
2345678
Figure 1-1. Site Location Map, Elmendorf AFB, AK
OU 3 Record of Decision, Final
1-2
January 1997
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ELMENDORF AFB
Figure 1-2. Location of OU 3 Study Area, Elmendorf AFB, AK
January 1997
1-3
OU 3 Record of Decision, Final
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1J2 Land Use
Land use for OU 3 includes base housing, maintenance, and equipment facilities. This includes
equipment storage, hangars, and snow melt accumulation areas. Other land uses include designated
outdoor recreation and open areas. The Base Master Comprehensive Plan has designated that present
land use will continue in the future. There are no wetlands, flood plains, or endangered species in OU 3.
1.3 Hydrogeology and Groundwater Use
The OU 3 study area is located in the glacial outwash plain portion of the base. The surface
sediments at OU 3 are typical of glacial deposits and consist predominantly of sand and gravel with
locally substantial amounts of silt. The outwash deposits are coarser grained (sands and gravels) in the
eastern portion of OU 3 and become more fine grained (sand, silts, and clays) in the western portion of
the operable unit.
Underlying the shallow glacial deposits is the Bootlegger Cove Clay Formation. This formation,
sometimes referred to as the "blue clay", consists of interbedded silt and clay deposits. The depth to the
top of the Bootlegger Cove Clay Formation, although locally variable, is generally greatest in the
northern portion of the base, becoming shallower toward the south and southeast. The formation is
exposed at the bluff along the Knik Arm and occurs within OU 3 at a depth of up to 50 feet and is
approximately 40 feet thick.
There are two aquifers underlying OU 3, an unconfmed shallow aquifer and a deep confined
aquifer. The aquifers are separated by the Bootlegger Cove Clay Formation (Figure 1-3). The
Bootlegger Cove Clay Formation serves as an aquitard separating the shallow and deep aquifers. The
shallow aquifer intersects the ground surface at some locations on the base, resulting in ponds, lakes, or
bogs. The depth to saturation in the aquifer varies from zero to approximately 50 to 60 feet along the
heights of the Elmendorf Moraine (north of OU 3). At OU 3, the depth to the top of the water table
ranges from 5 to 35 feet below the surface.
Groundwater flow in the shallow aquifer is to the south-southwest at OU 3 toward Ship Creek.
In the northern portion of OU 3, the groundwater gradient is approximately 69 feet per mile. In the
southern portion of OU 3, the gradient steepens to approximately 111 feet per mile. The hydraulic
conductivity for the shallow aquifer ranges from 0.1 to 0.3 centimeter/second. The transmissivity for the
aquifer ranges from 17,000 to 45,000 feetVday, and linear velocity is approximately 3.2 feet/day. The
water in the shallow.unconfined aquifer at OU 3 is not used for any purpose on base.
The deep aquifer consists of sand and gravel outwash deposits and is present at depths ranging
from 50 to 470 feet below the surface at OU 3. The groundwater in the deep aquifer flows regionally
toward Knik Arm in a west to northwest direction. The deep aquifer supplies large quantities of water
for light industrial use such as air conditioning cooling water and washing aircraft and vehicles. There
are three active base wells screened in the deep aquifer at OU 3 that were sampled during the remedial
investigation. Drinking water at the main base comes from Ft. Richardson. Water from the base wells,
screened in the deep aquifer, is used for drinking water for emergency purposes only. Contamination
resulting from OU 3 operations was not found in the base wells.
A hydraulic communication test between the shallow unconfined and deep confined aquifers
conducted at Operable Unit 2 (OU 2) is applicable to OU 3 due to the similarity of lithology between the
operable units. OU 2 is located adjacent to OU 3 to the northwest. Results from this test indicate that no
communication exists between the two aquifers. Based on the results of this test, combined with seismic
work performed at OU 3, as well as analytical sampling of base water supply wells screened in the deep
OU 3 Record of Decision, Final 1-4 January 1997
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N
O
3
OU3
Study Area
NOT TO SCALE
Knik Arm
Groundwater Flow
Gaining Area
Water Table /
Typically 5 to 35 feet
below ground surface
Bootlegger Cove Formation
Typically 5 to 200 feet thick
Unconfined Aquifer
(Sand and Gravel)
Typically 10 to 80 feet thick
with a 0- to 50-foot saturated thickness
Confined Aquifer
(Sand) Found 50 to 470 feet
below ground surface
and 550 feet thick
Figure 1-3. Hydrogeologic Conceptual Model
ELUENOI ORW lOrt/SS JH SAC
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aquifer, the Bootlegger Cove Clay Formation is believed to be a barrier for movement of groundwater
between the two aquifers.
OU 3 Record of Decision, Final 1-6 January 1997
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Section 2.0
SITE HISTORY AND ENFORCEMENT ACTIVITIES
The following subsections detail the contaminant history of OU 3, the regulatory and
enforcement history, the role of the response action, and the role of the community in defining the
response.
2.1 Identification of Activities Leading to Current Contamination at OU 3
As part of the ongoing mission at Elmendorf Air Force Base, shop facilities, storage buildings,
and hangars located within OU 3 are used to support base operations. These facilities have been in
operation for over 30 years. OU 3 consists of three source areas and Cherry Hill Ditch, which serves as a
receptor to potential contamination migrating from the eastern portions of the base.
SD16 is composed of an open, grassy field near Building 31-260 that was used in the 1950s and
1960s to dispose of shop wastes. Presently, the eastern portion of the area is occupied by heavy
equipment and the northern portion is used to stockpile snow during the winter. The disposal of shop
wastes no longer occurs at the site and any source of contamination has been removed.
The area encompassing SS21 includes concrete pads, formerly the location of Building 31-357.
This area was used as a storage site for PCB oil containing transformers during the 1970s. The area is no
longer used to store transformers.
SD31 is in the vicinity of Hangar 5/Building 32-060 and was used for general storage and
workshop space. It was reported that products used in the building were discharged into floor drains
which connected to a dry well. A dry well located on the northeast side of the building was used for
disposal of sewer-derived waste and later designated SD31. Discharge into the floor drains no longer
occurs and the dry well has been removed.
As mentioned above, Cherry Hill Ditch is an artificial drainage channel which flows westward
from the east-west runway toward Knik Arm. The area from the boundary with SD16 to the western
boundary of the base was originally designated as SD52. However, due to its current role in receiving
and channeling water runoff from the eastern portion of the base, the ditch was reclassified from a source
area to a receptor in 1993.
Environmental investigations have been conducted at OU 3 since the early-1980s. Several
studies discovered evidence of contamination in various parts of OU 3. The majority of these
investigations were broadly focused across Elmendorf AFB and covered only portions of the source
areas currently included in OU 3.
The first investigation to examine contamination at OU 3 was conducted by Engineering-Science
in 1983. The study was Phase I of the Installation Restoration Program (IRP) process and had the
objective of identifying potential environmental contamination associated with past disposal practices. A
Phase II Work Plan was also developed by Engineering-Science in 1983. In 1986 and 1987, Dames &
Moore performed Phase II, Stage 1 and Stage 2 investigations at OU 3. A Resource Conservation and
Recovery Act (RCRA) Facility Assessment was conducted by the Alaska Department of Environmental
Conservation (ADEC) in 1988 and consisted of a preliminary review and a visual site inspection of
potential source areas. Also in 1988, Harding Lawson conducted an IRP Phase II, Stage 3 investigation
at OU 3. IRP Phase III, Stage 3 and 4 studies were conducted by Black & Veatch in 1990. A Limited
January 1997 2-1 OU 3 Record of Decision, Final
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Field Investigation Work Plan and Draft Report was performed by CH2M Hill in 1992. In the summer
of 1993, a full scale Remedial Investigation (RI) was conducted by Radian Corporation. The RI
determined the nature and extent of contamination and the potential risks to public health and the
environment. The results were compiled and analyzed in an RI report. Alternatives for remedial action
were evaluated in detail in the OU 3 Feasibility Study (FS), submitted with the RI in March of 1995.
The RI/FS concluded that low levels of soil contamination at the source areas were primarily the
result of vehicular traffic, road paving, and pesticide application. PCB contamination present at one site
was the result of transformer storage. Limited shallow-aquifer groundwater contamination by solvents
and fuel related products was the result of disposal in open ditches and the spilling or leaking related to
underground storage tanks.
2.2 Regulatory and Enforcement History
Based on the results of environmental investigations, Elmendorf AFB was listed on the National
Priorities List by the U.S. Environmental Protection Agency (USEPA) in August 1990. This listing
designated the facility as a federal site subject to the remedial response requirements of the
Comprehensive Environmental Response, Compensation ?-. J Liability Act (CERCLA), as amended by
the Superfund Amendments and Reauthorization Act of 1986 (SARA). On November 22, 1991, the
U.S. Air Force (USAF), the USEPA, and ADEC signed the Federal Facilities Agreement (FFA) for
Elmendorf AFB. The contaminated areas of Elmendorf AFB were divided into seven OUs, each to be
managed as a separate region and investigated according to varying schedules.
In accordance with the FFA, the RI of OU 3 was conducted in the summer of 1993. The RI was
intended to investigate all possible past sources of contamination at OU 3, including past CERCLA and
RCRA sites. The RI determined the nature and extent of contamination and the potential risks to public
health and the environment. The results were compiled and analyzed in the RI Report.
During the RI investigation, a dry well and surrounding soil was removed at SD31. After the RI
was completed, a portion of Cherry Hill Ditch was reconstructed to regrade the ditch and remove soil
contamination. An enclosed storm drainage system was installed.
The Final RI/FS was submitted in March 1995. A Proposed Plan was distributed to the public on
June 20, 1995, and a public meeting to discuss the plan was held on July 12, 1995. At that time, the
identified preferred alternative was bioremediation. The USAF, USEPA, and ADEC agreed to a
treatability study to determine the effectiveness of this treatment alternative. The treatability study was
conducted during the Spring 1996 and demonstrated that the treatment would not reduce PCB
concentrations and could not achieve the soil cleanup goals. In July 1996, additional sampling was
performed at Source Area SS21 in order to further define the area of contamination and aid in the
selection of a feasible remedy from the alternatives identified in the Proposed Plan. Included in the
sampling program was the removal of one concrete pad and loading dock at the site and the collection of
surface and subsurface soil samples. Analytical results of the sampling confirmed the findings of the
remedial investigation conducted in 1993. The index of documents entered into the Administrative
Record for OU 3 is provided as Appendix A.
OU 3 Record of Decision, Final 2-2 January 1997
-------
2.3 Role of Response Action
This ROD is one of six RODs to be completed at Elmendorf Air Force Base. RODs have already
been completed and signed for OUs 1, 2, 4, and 5. The OU 3 and OU 6 RODs are expected to be
completed in 1996. Operable Unit 7 source areas are included in the OU 6 ROD.
The CERCLA process described above is intended to identify solutions to contamination issues
where they exist. The remedial action described in this ROD addresses threats to human health and the
environment posed by contamination at OU 3. The RI/FS Report defines these threats as both shallow-
aquifer groundwater and soil contaminants. Soil with contaminants that pose a potential threat to the
public will be removed, transported, and disposed in an appropriate facility. As a requirement of
previously signed RODs for Elmendorf Air Force Base, institutional controls have been established to
restrict the use of the shallow aquifer in the outwash plain on the base. These restrictions are enforced
through the Base Comprehensive Plan. Projects and other activities are reviewed during the planning
stage to ensure compliance with the Base Comprehensive Plan. In addition, construction projects and
other activities also undergo an environmental review. This review helps ensure compliance with
groundwater use restrictions.
2.4 Community Participation
Public participation has been an important component of the CERCLA process at Elmendorf
AFB in general, and at OU 3 specifically. Activities aimed at informing and soliciting public input
regarding OU 3 include:
Environmental Update: Environmental Update is a newsletter distributed to the community
and interested parties. It discusses the progress that has been made on operable units and advises
the public about opportunities to provide input concerning decisions to address contaminated
areas of the base. Aspects of the OU 3 CERCLA progress have been published in this
newsletter.
Community Relations Plan: The base environmental personnel maintain and regularly update
a Community Relations Plan. It describes how the base will inform the public of base
environmental issues and it solicits public comment on base environmental programs.
The Restoration Advisory Board/Technical Review Committee: Base personnel meet
regularly with representatives of the community to discuss base environmental programs and
solicit their comments.
Public Workshops: On February 5, 1992, approximately 75 people attended a public workshop
where base personnel discussed base environmental programs and encouraged public
participation.
Public Meeting: A public meeting was held in January 1994 at the Aurora School to present
the plans for reconstruction of Cherry Hill Ditch.
Videotape: Base personnel made a videotape describing base environmental activities. The
tape is shown to base employees as well as the general public.
Speakers Bureau: The 3rd Wing Public Affairs Office maintains a speakers bureau capable of
providing speakers versed in a variety of environmental subjects to military and civic groups.
January 1997 2-3 OU 3 Record of Decision, Final
-------
Newspaper Releases: News releases are published on significant events during the IRP. News
releases are made announcing all public meetings that are held to discuss proposed remedial
actions.
Information Repositories: Public access to technical documents is provided through
information repositories located at the Bureau of Land Management's Alaska Resources Library
and the University of Alaska Anchorage's Consortium Library. The information in the
repositories is also maintained in the administrative record. The remedial action was selected
based on the information held in the administrative record.
Display Board: During public functions, a display board, showing key elements and progress of
the Elmendorf AFB IRP, is used to communicate technical issues to the public. It is used during
both on-base and off-base events.
Proposed Plan: The OU 3 Proposed Plan was distributed to the public on June 20, 1995; a
public meeting was held July 12, 1995; and the public review period was from June 20 to
July 21, 1995. Comments from the public are contained in Part Ill-Responsiveness Summary of
this document.
Public Notice: Public notices have been issued prior to all significant decision points in the IRP.
For OU 3, public notice was issued for the Proposed Plan in the Anchorage Daily News
(June 18, 1995) and the Sourdough Sentinel (June 15, 1995).
Mailing List: A mailing list of parties interested in the restoration program is maintained by the
base. Notices and publications (news releases, including the OU 3 Proposed Plan meeting) are
released via the mailing list.
Responsiveness Summary: Public comments were received on the OU 3 Proposed Plan. The
USAF maintains a record of all comments and has published responses to the comments in this
Record of Decision.
All decisions made for OU 3 were based on information contained in the Administrative Record.
An index to the documents contained in the Administrative Record for OU 3 is provided as Appendix A.
OU 3 Record of Decision, Final 2-4 January 1997
-------
Section 3.0
SITE CONTAMINATION, RISKS, AND AREAS REQUIRING
RESPONSE ACTIONS
This section summarizes soil contamination at OU 3 and identifies the areas which may require
remedial action. One area was identified for response action based on the risk that contaminants pose to
human health and the environment. The basis of this analysis is the data collected during the Remedial
Investigation (RI) which identified the nature and extent of contamination in OU 3.
There are three source areas (SD16, SD31, and SS21) and one receptor (Cherry Hill Ditch) at
OU 3. Soil contamination is discussed below in terms of five geographic areas, including: source SD16.
source SS21. the cast intersource area. Cherry Hill Ditch, and the west intersource area. The locations of
these areas are shown in Figure 3-1. Shallow-aquifer groundwater contamination is discussed for two
areas of interest: the OU 3 east groundwater area (geographically containing source areas SD16, SS21,
and the east intersource area) and the OU 3 west groundwater area (geographically containing Cherry
Hill Ditch and the west intersource area). The locations of these shallow-aquifer groundwater areas are
shown in Figure 3-2.
Groundwater modeling was conducted as a part of the Operable Unit 5 (OU 5) investigation.
The modeling included a study of contaminant movement within groundwater across several operable
units at the base, including OU 3.
3.1 Nature and Extent of Contamination
During the Rl, samples of soil, sediment, and shallow-aquifer groundwater were collected and
analyzed for organic and inorganic constituents. Contaminants detected in the soil, sediments, and
shallow-aquifer groundwater include fuel products, volatile organic compounds (VOCs), semi-volatile
organic compounds (SVOCs), inorganic compounds, polychlorinated biphenyls (PCBs), and pesticides.
A detailed discussion of the determination of contaminants of potential concern (COPCs) is
included in the OU 3 Rl/FS Report (USAF, 1994). A list of the COPCs for OU 3 is included in
Appendix B of this ROD. In summary, COPCs were determined by statistically comparing site
analytical results with background/upgradient results available for the same constituents. Chemicals
retained as COPCs are those which were measured on-site at concentrations significantly above
background/upgradient concentrations of the same chemicals. Once COPCs were statistically
established, the list was further refined by removing affected analytes associated with analytical methods
that were determined to be non-representative of site conditions (within the range of background
concentrations), and analytes which had results that were all below instrument-specific detection limits
and were not second-column confined. The refined list of COPCs was then subjected to a conservative,
residential land use risk-based screening procedure during which maximum analyte concentrations were
compared with risk-based concentrations associated with: a) a systemic hazard quotient of 1.0; b) a
lifetime incremental cancer risk of 10"* for water; and c) a lifetime incremental cancer risk of 10'7 for
soil. This risk-based screen helped to produce a list of COPCs which were most likely to contribute
significantly to the risks associated with OU 3. Gasoline, diesel, and kerosene did not undergo the
rigorous statistical evaluations made on the individual compounds but were retained as COPCs.
January 1997 3-1 OU 3 Record of Decision, Final
-------
o
c
o
a.
o
V)
5'
Tl
5'
K)
North
7
ELMENDORF AFB
LEGEND
Source or R«c«ptor
Areas
wo IQOO rcn
Figure 3-1. Soil Areas of Interest at OU 3, Elmendorf AFB, AK
-------
3
O
ff
o
s?
O
iio'
I'
ta
North
WATER AREA
ELMENDORF AFB
Figure 3-2. Groundwater Areas of Interest at OU 3, Elmendorf AFB, AK
-------
3.1.1 Soil and Sediment
Soil data from OU 3 was evaluated by area based on surface and subsurface contaminant
occurrences. Sediment samples were collected at SD16 and Cherry Hill Ditch in areas where surface
runoff had deposited sediment. Contaminant migration into the subsurface soil from contaminant
sources is believed to be almost vertical due to the coarse, porous nature of the soil at OU 3.
Source SD16 Soil and Sediment Results
Several potential sources of contamination were identified at source SD16. These include a
snow melt runoff area, former solvent disposal trenches, heavy equipment storage and maintenance
activities, and potential fuel-related leaks from spills or near underground storage tanks. As a result of
present practices, the sources do not constitute an ongoing contamination threat. Contamination in the
soil at SD16 includes low levels of VOCs and SVOCs, generally within depths of 5 to 6 feet below the
surface. Metals and pesticides were also identified in soil and /or sediment samples.
The constituents found in the soil and sediments at SD16 were evaluated in a risk assessment
which is described in Section 3.3. Tables 3-1 and 3-2 list constituents found in the soil and sediment at
SD16 that were major contributors to risk. A complete list of constituents is included in the RI/FS report
for OU 3 (March 1995).
Source SS21 Soil Results
The results of the remedial investigation at source SS21 verified that PCBs are the principal soil
contaminants in this area. The most likely potential source of this contamination is leaks of PCB oil
from electrical transformers. Transformers are no longer stored at the site. Low levels of VOC and
SVOC contamination observed frequently in association with PCB contamination may also be related to
the transformer oils. Pesticides are present across the site as well as across the base. In addition, isolated
levels of arsenic and lead were detected at SS21. The metals may also be related to the transformer oils.
A treatability study was performed in 1996 on soil from SS21 to determine whether a
bioremediation technology would be effective in reducing the total PCB concentrations in soil and
concrete to less than 5 ppm. The bench scale study failed to demonstrate that PCB levels in either soil or
concrete could be reduced to the target level. An original concentration of 30 ppm PCBs was reduced
less than 18% (to approximately 24 ppm).
Also in 1996, a concrete pad and loading dock were removed from SS21 to facilitate additional
soil sampling activities. The removed concrete was designated investigation derived waste and since it
contained levels of PCBs greater than 50 ppm, it was classified as a Toxic Substances Control Act
material and disposed at a facility in the lower 48 which accepts CERCLA waste under the Off Site
Disposal Rule.
The additional sampling further defined the area at SS21 impacted by PCB contamination. Two
concrete pads remain at the site. These remaining pads were sampled for PCB contamination and results
show levels at or below 1.0 ppm PCBs.
The constituents in the soil at SS21 were evaluated in a risk assessment which is described in
Section 3.3. Table 3-1 lists constituents in the soil at SS21 that were major contributors to risk. A
complete list of constituents is included in the RI/FS report for OU 3 (March 1995).
OU 3 Record of Decision, Final 3-4 January 1997
-------
Table 3-1
Summary of Soil Contamination/Guidelines at Operable Unit 3
Elmendorf AFB.AK
Soil Location
SDI6
SS21
East Intersource
Area
SD52 (Cherry
Hill Ditch)
Contaminant
of Concern
PAHs
(benzo(b)fluoranthene)
Diesel
PCBs
(PCB-1260)
Arsenic
PAHs
(benzo(a)pyrene)
Diesel
PCBs
(PCB-1260)
PAHs
(benzo(b)fluoranthene)
Arsenic
Maximum
Concentration
(in parts per million)
15.5
130
27.6
26'
0.137
' 130
4.15
24.9
90.9*
Frequency
of Detection
(total bib/total
samples)
22/31
2/40
15/16
10/10
4/7
11/11
2/3
3/11
11/11
Guidelines*
(in parts per million)
0.88
2000"
5C
7.04"
0.088
2000"
5C
0.88
7.04"
RCRA Subpart S levels were originally used for screening in the Feasibility Study and Proposed Plan. However, the RCRA levels are 8 years old and no longer used
for the CERCLA program. Instead, slightly more stringent risk-based screening levels developed by EPA Region 3 have been used for screening.
* Slate of Alaska cleanup level D for underground storage tanks.
This level is the cleanup goal for OU 3 and is based on a site specific risk evaluation for PCBs. It is comparable to the risk of I ppm recommended in EPA Superfund
guidance for unrestricted residential use. A discussion on how the level was determined is included in Section 42 of this ROD.
' Arsenic levels exceed EPA Region 3 risk-based screening levels. Due to high local background levels and the lack of any identified source of arsenic on base, the
background level was used.
Result is for only one location. All other arsenic results for OU 3 are much lower and are in the range of naturally occurring concentrations.
January 1997
3-5
OU 3 Record of Decision, Final
-------
Table 3-2
Summary of
Surface Water and Sediment Contamination/Guidelines at Operable Unit 3
Elmendorf AFB, AK
Sediment
SD16
SD52 (Cherry
Hill Ditch)
Surface Water*
West Intersource
Contaminant
of Concern
PAHs
(benzo(a)pyrene)
Pesticides
(4,4-DDD)
PCBs
(PCB-1260)
Pesticides
(heptachlor epoxide)
PAHs
(benzo(b)fluoranthene)
Contaminant
of Concern
Pesticides
(4,4-DDT)
Copper
Selenium
Cadmium
Lead
Cyanide
Maximum
Concentration
(in parts per
million)
3.01
4.03
8.63
.680
3.98
Maximum
Concentration
(in parts per
billion)
0.0562
9.7
29.6
3.46
22
9.8
Frequency
of Detection
(total hits/total
samples)
2/2
I/I
22/43
3/43
7/10
Frequency
of Detection
(total hits/total
samples)
2/2
2/2
2/2
2/2
2/2
2/2
Guidelines*
(in parts per
million)
0.088
1.9
No Established
Guideline
0.07
0.88
Guidelines'
(in parts per
billion)
0.2
500
ISO
18
15"
730
' RCRA Subpart S levels were originally used for screening in the Feasibility Study and Proposed Plan. However, [he RCRA levels are 8 years old and no longer used
for the CERCLA program. Instead, slightly more stringent risk-based screening levels developed by EPA Region 3 have been used for screening.
* USEPA Region 3 has nol listed a risk based screening level for lead. Therefore, the level listed is from the Safe Drinking Water Act.
c Media investigated as surface water; however, actually represents storm water at the base.
OU 3 Record of Decision, Final
3-6
January 1997
-------
East Intersource Area Soil Results
The east intersource area includes former source SD3I, as well as additional pilot borings for
monitoring wells which were installed in the eastern and southern portion of OU 3. The dry well and
surrounding soil at SD31 were excavated in July of 1993. The dry well was found to be the repository
of sewer-derived waste with a minor amount of petroleum compounds. After all the sewer waste and
petroleum-impacted soil (measuring approximately 38 feet long, 22 feet wide, and 20 feet deep) was
removed, soil samples were collected from the sides and bottom of the excavation to confirm that the
contamination had been removed.
Very low levels of soil contamination were detected in the soil samples collected in the east
intersource area. Low concentrations of VOCs were detected in confirmation samples collected after the
dry well had been removed at SD31. Low levels of VOCs (including BTEX and solvent-type VOCs), as
well as SVOCs, were also detected in the soil borings in the east intersource area. Pesticides and metals
were also detected, but at low levels.
The constituents remaining in the soil at the east intersource area after the excavation was
completed were evaluated in a risk assessment which is described in Section 3.3. Table 3-1 lists
constituents at the east intersource area that were major contributors to risk. A complete list of
constituents is included in the RI/FS report for OU 3 (March 1995).
Receptor SD52 (Cherry Hill Ditch) Soil and Sediment Results
Soil and sediment contamination was found in Cherry Hill Ditch during the remedial
investigation. The predominant contaminants were PCBs and pesticides. Cherry Hill Ditch receives
runoff from the east-west runway as well as other areas on the eastern half of the base. The most likely
source of the contamination is the surface runoff of contaminated water and deposition of contaminated
particles migrating downstream from other parts of the base through the storm water system.
At Cherry Hill Ditch, elevated PCB and pesticide concentrations were detected south of the
intersection of the ditch with Acacia Street. The highest level of PCBs detected at Cherry Hill Ditch was
in the sediments at 39.4 mg/kg. Ethylbenzene and xylene were the primary VOCs detected. Elevated
concentrations of diesel, kerosene, polynuclear aromatic hydrocarbons (PAHs, or PNAs), and phthalates
were also detected in surface soil and sediment samples. Most of the locations where these contaminants
were detected coincided with the PCB occurrences. Among the inorganic constituents; arsenic, lead,
manganese, and zinc were detected.
From May to July of 1994, after the RJ investigation was completed, the section of Cherry Hill
Ditch between Acacia Drive and Cherry Street was reconstructed to regrade the ditch area and install an
enclosed storm drainage system. The area of reconstruction is shown in Figure 3-3. A portion of the
ditch approximately 10 feet long (along the flow line), two feet wide, and thirty inches deep was
excavated around the sediment sample with the highest PCB contamination. After the soil was removed,
samples were collected from the surrounding sediment to confirm that the area of highest contamination
was removed. Sample results after excavation ranged from 3.38 to 8.63 mg/kg PCB-1260. These sample
results were included in the evaluation of current risk at the site.
A new 36-inch diameter high density polyethylene (HDPE) storm drain, approximately
1,900 feet in length, was installed parallel to Cherry Hill Ditch. This new drain carries storm water from
the outlet of existing drains just south of Acacia Drive to an existing storm drain vault just north of
Cherry Street. A 100-foot long, 12-inch diameter HDPE storm drain was installed in the ditch to drain
January 1997 3-7 OU 3 Record of Decision, Final
-------
o
73
n
n
o
3.
T)
UJ
oe
AREA OF
EXCAVATION
CHERRY HILL
RECONSTRUCTION
AREA OF
RECONSTRUCTION
§
I
Figure 3-3. Location of Excavation and Reconstruction at Cherry Hill Ditch, Elmendorf AFB, AK
-------
water from just south of sample location SD19 to the inlet of the 36-inch pipe. The bottom of the
existing ditch was lined with an erosion control fabric. The ditch was then filled with a layer of
unclassified fill, a layer of drain rock, and 2 to 4 inches of topsoil. During times of normal surface water
flow, discharge will continue to flow in the former ditch area that has been filled with drain rock. The
HDPE storm drain will carry overflow during episodes of high discharge.
The sediment remaining in place at Cherry Hill Ditch is no longer considered sediment since it is
beneath the surface. The PCBs are not expected to be mobile and any pathways to reasonable exposure
have been eliminated. The constituents remaining in the soil at Cherry Hill Ditch were evaluated in a
risk assessment which is described in Section 3.3. Tables 3-1 and 3-2 list constituents remaining that
were major contributors to risk. A complete list of constituents is included in the RI/FS report for OU 3
(March 1995).
West Intersource Area Soil Results
Soil samples were collected during the drilling of ground water monitoring wells in the west
intersource area. In general, very little contamination was identified in the soil in this area of OU 3. The
contaminants detected are consistent with low levels of VOCs, SVOCs, and metals that are common
across OU 3. The observed contamination is likely the result of runoff from nearby parking lots,
vehicular activity, or the deposition of fugitive dust. The constituents found in the soil at the west
intersource area were evaluated in a risk assessment which is described in Section 3.3. A complete list of
constituents is included in the RJ/FS report for OU 3 (March 1995).
3.1.2 Groundwater
Shallow-aquifer groundwater contamination is discussed for two areas: the OU 3 east
groundwater area (geographically containing source areas SD16, SS21, and the east intersource area) and
the QU 3 west groundwater aj-ea (geographically containing Cherry Hill Ditch and the west intersource
area). Isolated contaminants were detected in the shallow aquifer in groundwater wells at OU 3. The
contamination was found in several wells but at low concentrations and no groundwater plumes could be
identified at the OU 3 source areas. As indicated in Section 1.3, samples collected from base wells
screened in the deeper aquifer do not indicate that contamination exists resulting from OU 3 operations.
OU 3 East Groundwater Results
Benzene, trichloroethene (TCE), dichloroethene (DCE), and tetrachloroethene (PCE) were
detected in the shallow aquifer in wells in the OU 3 east groundwater area. Sources for these compounds
could include the former earthen disposal trenches, heavy equipment storage and maintenance activities,
and leaks or spills in the vicinity of underground storage tanks at SD16.
Table 3-3 lists a summary of highest detections of contaminants found in the shallow aquifer in
the OU 3 east groundwater area. The majority of the detections are associated with TCE and other
halogenated VOCs, which also exceeded potential regulatory levels. Although TCE and benzene were
found in 70% and 50% of the wells respectively, they are at very low levels (less than MCLs in most
wells). The first sampling event occurred at the beginning of the field program before most of the wells
were installed. All wells were sampled in events 2 and 3.
January 1997 3-9 OU 3 Record of Decision, Final
-------
Table 3-3
Summary of
Shallow-Aquifer Groundwater Contamination/Guidelines at Operable Unit 3
Elmendorf AFB,AK
Location
East Intersource Area
(includes Sites
SD3I.SD16, SS21)
West Intersource
Area (includes Site
SD52)
Contaminant of Concern
TCE
PCE
Benzene
Methylene chloride
bis(2-cthylhexyl)phthalate
Cadmium
Lead
bis(2-ethy Ihexy 1 )phihalate
Cadmium
Maximum
Concentration
(in parti per billion)
140
9.37
6.17
6.43
1,150
25.6
26
520
7.4
Frequency of
Detection (total
hits/total
samples)
26/36
2/36
18/36
1/35
5/35
17/36
29/36
7/21
5/21
Guidelines'
(in parts per
billion)
5
5
5
5
6
5
15
6
5
1 For this table, the Primary Federal Drinking Water Standard Maximum Contaminant Levels are used.
OU 3 West Groundwater Area Results
To characterize the depth to the top of the water surface of the shallow aquifer in the southern
portion of OU 3 and thus to fill basewide hydrogeologic gaps, three groundwater monitoring wells were
installed in the west intersource area. In addition, six wells were installed adjacent to Cherry Hill Ditch
to determine the relationship between the ditch and the shallow aquifer.
Several VOCs were detected in shallow-aquifer groundwater samples including chloroform,
chloromethane, 1,1,1-trichloroethane, trichloroethene, and trichlorofluoromethane. Isolated occurrences
of bis(2-ethylhexyl)phthalate were observed intermittently in samples. Cadmium and vanadium were the
only inorganic COPCs detected in the shallow-aquifer groundwater samples.
Table 3-3 lists the levels of the highest detections of contaminants in the shallow aquifer in the
OU 3 west groundwater area.
3.2 Groundwater Modeling
Groundwater flow in the shallow aqujfer at OU 3 is to the south, toward OU 5, where several
sensitive receptors are present: Ship Creek, beaver pond wetland areas, drainage ditches, and seeps. The
OU 5 groundwater model ing report, which included modeling of basewide groundwater contamination
over the next 30 years, predicts that organic contaminants within the shallow aquifer at OU 3 will
naturally attenuate before reaching Operable Unit 5. Therefore, OU 3 is not expected to have an impact
to sensitive receptors.
OU 3 Record of Decision, Final
3-10
January 1997
-------
3.3 Risk Evaluation
Based on the concentrations of contaminants detected during the RI, human health and
environmental risk assessments were performed to determine if areas should be considered for remedial
action. All concentrations of contaminants, including all potential contaminants of concern, whether
exceeding potential regulatory levels or not, were included in the risk assessment. At Cherry Hill Ditch
and SD31, the constituents remaining in the soil after completion of the removal actions were included
in the risk assessment. Since soil was not removed from SS21 (only concrete), the highest soil PCB
results were included in the risk assessment.
Human Health Risk Assessment (HRA)
By determining under what land use conditions people are potentially exposed to what
chemicals, for how long, and by what pathways of exposure, the cancer and noncancer risks were
determined in the RI/FS.
Exposed Populations and Exposure Pathways Listed below are five possible exposure
pathways to contamination. Details on the parameters used in the Health Risk Assessment are shown on
Table 3-4.
Future On-Site Resident: The HRA evaluated exposure of residents to contaminated surface
soil through direct contact (incidental ingestion and dermal absorption) and inhalation of dusts.
Their exposure to shallow-aquifer groundwater through ingestion, inhalation (showering), and .
dermal contact (showering) was also evaluated.
Future On-Site Worker: The HRA evaluated exposure of workers to contaminated subsurface
soil through direct contact (dermal absorption and incidental ingestion) and inhalation of vapors
from the soil. Ingestion of on-site water was also evaluated.
Current On-Site Worker: The HRA evaluated exposure of workers to contaminated surface
soil through direct contact (incidental ingestion and dermal absorption) and inhalation of dusts.
Construction Worker: The HRA evaluated exposure of short term construction workers to
contaminated subsurface soil through direct contact (incidental ingestion and dermal absorption)
and inhalation of dusts.
Hypothetical Visitor: The HRA evaluated exposure of an adult and child visitor to
contaminated surface soil through direct contact (incidental ingestion and dermal absorption) and
inhalation of dusts.
Exposure Assumptions Risk can be calculated both for the average exposure and the
reasonable maximum exposure (RME) of the population. All chemicals detected during sampling were
evaluated as potential sources of cancer and noncancer health risks. In the case of metals, risks were
only calculated if the metals concentrations exceeded background concentrations. Background metals
concentrations in groundwater were collected by the U.S. Geological Survey (USGS) in the Anchorage
Bowl area and compiled in the ElmendorfAir Force Base, Base-wide Background Sampling Report
(USAF, 1993). These metals data have been used historically at Elmendorf AFB for comparison with
on-site groundwater metals concentrations. Confidence intervals of the USGS data mean for a given
metal were compared with confidence intervals for the OU 3 analytical results for the same analyte. If
the confidence intervals of the two means overlapped, the two means were considered not to be different
and the particular metal was removed from consideration as a COPC. Based on this evaluation, all
January 1997 3-11 OU 3 Record of Decision, Final
-------
8
u>
&
o
5.
o
Table 3-4
Exposure Assumptions for Oil 3, Elmendorf AFB, AK
Parameters
Body Weight (kg)
Exposure Duration (yrs)
Averaging time (carcinogens) (yrs)
Averaging time (noncarcinogens) (yrs)
Total inhalation rate (m'/day)
Soil Ingestion/Contact
Soil Ingest ion Rate (mg/day)
Soil to Skin Adherence Factor (mg/cnu)
Exposed Skin .
1 -A posed l:requency (days/yr)
Exposure Duration (yrs)
Water Use
Water Ingestion (1 'day)
Indoor Inhalation Kate (m'/day)
F.xposure Frequency (days/yr)
Skin Surface (cm1)
Shower Duration (min)
Hypothetical On-Site Residential
Adult
RME
70'
30'
70"
NA
20d
200/100"
lf
5000"
I85»
24/6"
2AJ
15'
350"
2300()f
I5f
Average
70'
9b
70d
NA
20J
100"
.02f
1900"
IIO»
9"
1.4'
15'
275'
20000r
I0f
Child
RME
15'
6"
N
b<
I6C
200/100"
lf
3900"
185"
24/6"
.OT
I2C
350"
10.600'
I5f
Average
15'
6"
NA
6"
16"
I00b
0.2f
1900"
110
6
0.41V
12
275
8,660
10
On-Site Occupational
Current
RME
70'
25'
70d
25J
20"
501
lf
3l60f
SS"
NA
NA
NA
NA
NA
Hypothetical
RME
70"
25'
70"
25"
20*
50"
lf
3160'
I85«
1'
NA
250*
NA
NA
Construction
Worker
RMC
70'
lc
70"
ld
20d
480'
1'
3160f
40C
NA
NA
NA
NA
NA
Visitor
Adult
RME
70'
3()c
IV
30d
20"
200/100"
lf
5000"
I2C
24/6"
NA
NA
NA
NA
NA
Child
RME
15'
6C
70d
6"
I6C
200/100"
1'
1900"
I2C
24/6"
NA
NA
NA
NA
NA
O
K>
' UShl'A. Risk Assessment Guidance'for Siincrfiiml Voluine I - Human lleallh I-valuation Manual. Supplemental Guidance. Inlrciin Final Report, Office of Emergency and Remedial Response, Washington, D.C., 1991.
uUStPA. Supplemental Guidance for Sunerfmid Risk Assessments in Region X 1-l'A 9IO/9-9I-OJ6. August 23, 1991.
' Tlie construction worker scenario evaluates deep soil risk.
' USnt'A. Hi»k A»ses»inenl Ciiiiilancc for Siinerfuml Volume I Human llcnllli livnluiilion Manual. I'art A. liilcrim I iiwl Rcjxirl Ollitc of l-jiicrgeiicy and Remedial Kespousc. Wiisliingion, D.C., Deccinlicr 1989.
USI-I'A l-»no»ure Facliirs Handbook. Office of Health and Ijivnon.ncniul Assesstnent. Waslunglon. L> C . I9S9. .
1 USIil'A, Denial Runosnre Asstssnitnl: Principles and Applications Interim Report. Office of Health and Environmental Assessment, Washington, D.C., January 1992.
Darnack. K. Personal Communications. 1994
' Site Specific
NA
Not applicable.
Reasonable Maximum Exposure.
-------
metals in groundwater at OU 3 were determined to be at background concentrations. The USGS mean
concentrations used for the comparisons are the following for the metals in question:
Antimony: 0.002 mg/L
Arsenic: 0.029 mg/L
Lead: 0.028 mg/L
Manganese: 6.81 mg/L
Average exposure risks were assessed using the measured concentrations at the site. RME risks were
assessed using the 95% upper confidence limit (UCL) of the arithmetic mean concentration in soil and
shallow-aquifer groundwater.
Conservative assumptions were used to avoid underestimating risk (Table 3-4). For example, the
HRA assumed that future residents would live where the contaminants are located for 30 years and they
would drink and shower with the contaminated, shallow-aquifer groundwater. This is a highly
conservative assumption since the primary land use of the OU 3 area is not conducive to residential
development and military personnel typically reside on-base for only 3 to 8 years. Snow and ice cover
the ground for part of the year which reduces the exposure to the soil. To account for this, an average
exposure of 110 days was used in the risk assessment. In addition, the shallow aquifer is not used for
drinking water and is unlikely to be used as a water supply in the future because of its poor yield relative
to the deep, confined aquifer.
Using exposure levels and standard values for the toxicity of contaminants, excess lifetime
cancer risks (ELCRs) and hazard indices (His) were calculated to describe cancer and noncancer risks,
respectively. The ELCR is the additional chance that an individual exposed to site contamination will
develop cancer during his/her lifetime. It is expressed as a probability such as 1 x 10"6 (one in a million).
The HI estimates the likelihood that exposure to the contamination will cause some negative
health effect. An HI score below one indicates that people exposed to the contamination will not
experience at least one health effect. The His at OU 3 were all less than 1.
ELCRs and His were calculated using Reference Doses (RfDs) and Cancer Slope Factors (CSFs)
which represent the relative potential of compounds to cause adverse noncancer and cancer effects,
respectively.
Two sources of RfDs and CSFs were used for this assessment. The primary source was
Integrated Risk Information System (IRIS) database, the USEPA repository of agency-wide verified
toxicity values. If a toxicity value was not available through IRIS, then the latest available quarterly
update of the Health Effects Assessment Summary Tables (HEAST) issued by the USEPA's Office of
Research and Development was used as a secondary source. For some chemicals detected at OU 3, no
toxicity value from IRIS or HEAST was available, and toxicity values were provided by EPA Region X
as provisional RfDs and cancer slope factors.
Table 3-5 summarizes the carcinogenic human health risks calculated for OU 3. The risks are
based on hypothetical exposure to soil and shallow-aquifer groundwater. The shallow groundwater
January 1997 3-13 OU 3 Record of Decision, Final
-------
aquifer is not presently used and will not be used in the future for supplying potable or non-potable
water. For carcinogenic soil risk, the calculated results for the future resident (RME), which evaluate
surface soil risks, are listed for SD16, SS21, east and west intersource areas, and the groundwater areas.
The construction worker scenario results, which evaluates subsurface soil risk, is provided for Cherry
Hill Ditch.
Table 3-5
Summary of Health Risks at Operable Unit 3, Elmendorf AFB, AK
Site
Source SD16
Source SS21
East Intersource Area
Receptor SD52b
West Intersource Area
Site
OU3 East Groundwater (Shallow Aquifer)
OU3 West Groundwater (Shallow Aquifer)
Soil Risk*
5.3 x ID'5
1.1 x IO-1
l.Ox 10*
9.9 x ID'7
1.9x IO'7
Groundwater Risk*
3.0 x 10"'
2.1 x 10"s
Major Contributors
and Percentage of Contribution
Benzo(a)pyrcne (34%)
Arsenic (31%)
Benzo(b)f!uoranthene (5%)
Arsenic (24%)
PCB-1260(71%)
Benzo(a)pyrene (98%)
PCB-1260(44%)
Arsenic (25%)
Benzo(a)pyrene (17%)
Arsenic (98%)
Major Contributors
and Percentage of Contribution
Chloroform (5%)
bis(2-ethylhexyl)phthalate (53%)
Trichloroethene (32%)
Chloroform (25%)
bis(2-ethylhexyl)phthalate (75%)
Note: Risks presented are for carcinogenic health risks at OU 3. Non-carcinogenic risks were examined; however, all were determined to be
less than I (i.e. His were less than I).
* Risks are calculated under the most conservative scenario which is excess cancer risks conservatively assumed for 30 years of exposure by
future residents (Reasonable Maximum Exposure).
* The risks at receptor SDS2 are calculated under the most likely scenario which is that of a construction worker in contact with subsurface
soils. This risk is calculated as excess cancer risks conservatively assumed for I year of exposure during on-site construction work.
The presence of PCBs in the soil at SS21 resulted in a risk of 1.1 x 10"1. This risk occurs for a
future 30-year resident, the most conservative scenario. For all the other areas at OU 3, the risk is below
10"6 or within the range of 10'5 to 10"*. Risks did not exceed 1 x 10"* in groundwater at OU 3. This risk is
based on future residents drinking and bathing with the shallow-aquifer groundwater in the area for 30
years.
In order to determine a cleanup level for PCBs at SS21, a risk evaluation was performed using
the same conservative assumptions. Under site conditions, a cleanup level of 5 ppm PCBs was
determined to be comparable to the EPA standard default risk of 1 ppm (EPA PCB superfund guidance
for unrestricted residential use). This means that if SS21 contains less than 5 ppm PCBs, the site will be
available for unrestricted use.
OU 3 Record of Decision, Final
3-14
January 1997
-------
Risks were calculated using assumptions regarding exposure pathways and the time receptors
were exposed to the contaminants. Each exposure was estimated in a conservative manner. Risk
management decisions were made considering the uncertainty in the assumptions used in the risk
assessment. At OU 3, the shallow groundwater is not used and is not expected to be used in the future,
so existing risks and potential risks are significantly less than the worst-case risk.
Ecological Risk Assessment (ERA)
The ERA was performed to determine if the reported concentrations of chemicals or calculated
exposures to plants and wildlife at OU 3 are likely to produce adverse effects. Ecological effects were
evaluated quantitatively by calculating Ecological Quotients (EQs). EQs are defined as the ratio between
measured concentrations or predicted exposures and critical effects levels. If an EQ is less than 1.0, the
effect is unlikely to occur. Critical effects are defined in the selection of assessment and measurement
endpoints. Assessment endpoints are the general environmental resource or value that is being protected.
A measurement endpoint is a specific criterium that is used to evaluate the more general assessment
endpoint.
Compared to undeveloped portions of the base, the sites that comprise OU 3 do not contain
major ecological resources. The naturally occurring vegetation has been removed from most of the
areas. The existing vegetation in the contaminated areas varies from barren to sparse grassy areas.
The moose, black-capped chickadee, masked shrew, merlin, peregrine falcon, and meadow vole
were selected as indicator species for the ERA. Exposures to all indicator species were evaluated for
surface soils at Cherry Hill Ditch. Only meadow vole exposures were evaluated for the other sources
because it is the only indicator species that occurs regularly in these areas. The EQ of 1.0 was exceeded
for meadow voles at SD16, SS21, east intersource area, and west intersource area; however, the upper
threshold limit of the background concentrations would also exceed 1.0. This fact indicates that the
modeled doses or reference criteria represent naturally occurring risks. In the case of selenium, the
concentrations in the soil are likely to be biased high due to interferences in the analysis. At Cherry Hill
Ditch, the EQ was exceeded for black-capped chickadee, masked shrew, and meadow voles before
reconstruction of the ditch. Since the remaining contamination, after construction, is below the surface,
it is unlikely that a significant population of these indicator species or other animals is threatened by the
contaminants.
No significant impacts to plants or animals warranting action were determined to be present
based on the results of the ERA.
Uncertainties Associated with the Risk Assessment
Risk assessments involve calculations based on a number of factors, some of which are
uncertain. Some of the major assumptions and uncertainty factors associated with the risk assessment
are the following:
Constituent concentrations were assumed to be equal to the 95% Upper Confidence Limit
(UCL), which is likely biased high (may overestimate risk).
Existing concentrations are assumed to be the concentrations in the future. No reduction through
natural degradation and attenuation over time is taken into account (may overestimate risk).
No increase through additional contamination is assumed (may underestimate risk).
January 1997 3-15 OU 3 Record of Decision, Final
-------
Potential degradation products of existing organic contaminants are not considered (may
overestimate or underestimate risk).
3.4 Summary
Actual or threatened releases of contaminants from OU 3, if not addressed by implementing the
response action selected in this ROD, may represent an imminent and substantial endangerment to public
health, welfare, or the environment.
Actions at Cherry Hill Ditch and SD31 resulted in the removal of contaminated soil from these
source areas. The risks for soil at SD31, SD16, and Cherry Hill Ditch are considered acceptable and
resulted in no further action decisions for the soil at SD31, SD16, and Cherry Hill Ditch. These sites are
available for unrestricted use. The only contaminant of concern for soil at OU 3 is PCBs at SS21.
The risks for groundwater, based on both organic and inorganic concentrations, are acceptable.
No current receptors exist for groundwater at the base due to institutional controls. The only potential
receptor of groundwater is at OU 5 and this is addressed in the OU 5 ROD. For these reasons, it was
determined remedial action is not required for groundwater at OU 3.
OU 3 Record of Decision, Final 3-16 January 1997
-------
Section 4.0
REMEDIAL ACTION OBJECTIVES, ALTERNATIVES, AND
COMPARATIVE ANALYSIS
The following subsections discuss the contaminants of concern (COCs) for OU 3 and present the
site requiring remedial action. In addition, remedial action objectives are presented for OU 3, as well as
a description of the various cleanup alternatives which were evaluated to achieve those remedial
objectives. The results of the detailed comparison made between those alternatives are also presented.
4.1 Contaminants of Concern and Need for Remedial Action
COCs were developed from the results of the risk assessment. By comparing contaminant
concentrations in soil with cleanup standards, risk-based criteria, and interim remediation goals, the
COC for soil at OU 3 is PCBs at site SS21. Although other contaminants at other sites at OU3 exceeded
interim remediation goals or action levels, the resulting risks were considered acceptable. The risks for
soil at SD31, SD16, and Cherry Hill Ditch are considered acceptable and this resulted in no further action
decisions for the soil at SD31, SD16, and Cherry Hill Ditch. These sites are available for unrestricted
use. The presence of PCBs in the soil at SS21 results in an unacceptable risk and the need for remedial
action.
Although organic constituents (e.g., TCE) are present above Maximum Contaminant Levels
(MCLs) in the shallow groundwater aquifer beneath OU 3, the concentrations are generally low, there
are no current receptors, and institutional controls at the base exist for the shallow aquifer to prevent use.
Metals were also identified above MCLs; however, based on a comparison of metals concentrations in
the shallow-aquifer groundwater beneath OU 3 and background concentrations, the metals were
determined to be at or below background concentrations (Section 3.3).
All sources of groundwater contamination in OU 3 have been or will be addressed as a part of
the remedial action at OU 3. No current receptors exist for groundwater at the base due to institutional
controls. As a requirement of previously signed RODs for Elmendorf Air Force Base, institutional
controls have been established to restrict the use of the shallow aquifer in the outwash plain on the base.
These restrictions are enforced through the Base Comprehensive Plan. Projects and other activities are
reviewed during the planning stage to ensure compliance with the Base Comprehensive Plan. In addition,
construction projects and other activities also undergo an environmental review. This review helps
ensure compliance with groundwater use restrictions. For these reasons, it was determined remedial
action is not required for groundwater at OU 3.
The identification and screening of remedial technologies and the detailed analysis of
alternatives was based on remediating PCBs in shallow soil at SS21. Figure 4-1 shows the approximate
location of impacted soil at SS21.
4.2 Remedial Action Objectives and Goals
Specific remediation alternatives were developed and evaluated for PCBs at SS21. Remedial
action objectives are:
Protect human health and the environment by reducing the risk from the potential exposure to
PCBs in surface soil;
Clean up PCB-contaminated soil to below the established cleanup level;
January 1997 4-1 OU 3 Record of Decision, Final
-------
o
OJ
o
o
s.
o
n
D
o
o
5'
5'
*
TI
5'
K>
ELMENDORF AFB
LEGEND
APPROXMATt AREA OF
MACTED SOU
Figure 4-1. Approximate Area of Impacted Soil at Source Area SS21, Elmendorf AFB, AK
-------
Protect uncontaminated media during cleanup activities; and
Restore contaminated media for future land uses.
The remedial action goal is to achieve a cleanup level of 5 ppm PCBs. The contamination is
limited to soil only (single media), is at relatively low levels, is localized, is relatively immobile, and is
nonvolatile in nature. A screening risk assessment was performed using the conservative, residential land
use scenario. The exposure assumptions are listed in Table 3-4 and include the assumption that family
housing will be built on the site. An average exposure of 110 days was used to account for the presence
of snow and ice covering the ground for most of the year. Using the screening risk assessment, a level of
5 ppm PCBs was selected as the cleanup level for SS21 because it represents a risk which, based on site
conditions, is comparable to the standard EPA Superfund PCB guidance level (1.0 ppm) for unrestricted
residential use.
4.3 Alternatives
Remedial action alternatives were identified that specifically address soil contamination
containing PCBs. Five remedial alternatives were identified to address the contamination scenario at
SS21.
Alternative 1: No Action
Evaluation of this alternative is required by CERCLA as a baseline reflecting current conditions
without any cleanup. This alternative is used for comparison with each of the alternatives. While natural
processes should degrade and reduce the concentrations of the chemicals over time, PCBs are very stable
and the timeframe to achieve cleanup levels is indefinite. This alternative does not include any
long-term monitoring. There are no costs associated with this alternative.
Cost: None
Alternative 2: Capping
This alternative involves the installation of an asphaltic concrete cap over all soil contaminated
above 5 ppm PCBs. The cap would cover approximately 1,000 square feet. A cap would eliminate the
migration pathways and exposure pathways, thus protecting human health, plants, and animals. Because
PCBs are very stable, the time required to achieve cleanup levels is indefinite. Maintenance actions, for
example repaying and crack repair, would be required over the life of the cap to maintain effectiveness.
Cost: $568,000 (Includes 30 years of maintenance. Cost of maintenance will extend past 30
years for an indefinite period of time.)
Alternative 3: Excavation and Off-Site Disposal
For this alternative, all soil above the cleanup level (estimated to be 200 cubic yards) would be
excavated and shipped to a disposal facility which is acceptable for disposal of CERCLA waste under the
Off-site Disposal Rule (40 CFR 300.440). The cleanup level was determined to be 5 ppm based on a risk
evaluation using site conditions. Clean soil would be backfilled to restore the original grade of the site.
The soil volume for this alternative was stated in the Proposed Plan (June 1995) to be 640 cubic
yards. The cost indicated in the Proposed Plan was $671,000. The additional sampling performed at SS21
January 1997 4-3 OU 3 Record of Decision, Final
-------
further delineated the area impacted by PCBs and resulted in a lower volume of impacted soil and a
lower cost.
Cost: $170,000
Alternative 4: In-Situ Bioremediation
This alternative was included in the Proposed Plan (June 1995) as the preferred alternative and
involves the degradation of PCBs through biological activity in the soil. All soil above the cleanup level
(5 ppm) would be treated. Biological organisms and additives such as nutrients, water, and air would be
added by mechanical spraying to maximize treatment effectiveness. A treatability study was performed
in the spring of 1996 to determine if bioremediation would be effective at reducing the concentration of
PCBs in the soil. The results of this study indicated that bioremediation is not an effective alternative for
reducing the concentrations of PCBs at SS21. The study and results are presented in the biotreatability
study final report (September 1996).
Cost: $ 181,000 (Includes treatability study.)
Alternative 5: Excavation and On-Site Treatment
This alternative was listed in the Proposed Plan (June 1995) as the contingency alternative and
involves the excavation and on-site treatment of approximately 200 cubic yards of contaminated soil.
All soil above the cleanup level (5 ppm) would be treated. An on-site treatment technology would be
used for remediation such as soil washing or thermal desorption. The specific technology would be
developed in the remedial design. A treatability study would be performed during the remedial design to
determine necessary treatment procedures needed to achieve the cleanup levels. After the procedures
have been defined, the contaminated soil would be excavated and processed through the treatment
system; the treated soil would be backfilled on site. Any residuals left from the treatment would be
properly disposed at a permitted disposal facility, if applicable.
The soil volume for this alternative was stated in the Proposed Plan (March 1995) to be 640
cubic yards. The additional sampling performed at SS21 further delineated the area impacted by PCBs
and resulted in a lower volume of impacted soil. The cost was not significantly affected by the decrease
in soil volume because of the large mobilization cost associated with this alternative.
Cost: $791,000
Costs and time to clean up for all alternatives are presented in Table 4-1.
OU 3 Record of Decision, Final 4-4 . January 1997
-------
Table 4-1
Cost and Duration for Remedial Alternatives
Alternative
1 : No Action
2: Capping
3: Excavation and Off-Site Disposal
4: In-Situ Bioremediation
5: Excavation and On-Site Treatment
Costs (S)
Capital Cost
0
464,000
170,000
181,000
791,000
Annual Cost
0
8,400
0
0
0
Present
Worth Cost*
0
568,000
170,000
181,000
791,000
Time to Achieve
Cleanup Goals
(Years)
0
Indefinite
1
a
1
* A discount rate of 7% was applied to annual costs in the present worth calculation.
' This alternative was evaluated in a treatability study and determined not to be effective in reducing PCB contamination in soil.
4.4 Summary of Comparative Analysis of Alternatives
The comparative analysis describes how each of the alternatives meet the CERCLA evaluation
criteria relative to each other.
4.4.1 Threshold Criteria
Protection of Human Health and the Environment
All alternatives, except the No Action and In-Situ Bioremediation alternatives, are protective of
human health and the environment. Alternative 2, capping, would provide protection because
contaminants would be inaccessible to the public due to their presence under the cap. Soil would not be
removed, so disposal concerns and short-term exposure would be minimal. However, Alternative 3,
Excavation and Off-Site Disposal, and Alternative 5, Excavation and On-Site Treatment, would be less
protective of human health while the soil is being excavated and handled. However, the soil would be
removed or treated, thereby eliminating any threat to future exposure. The potential for air emissions
during on-site soil treatment makes Alternative 5 somewhat less protective of human health and the
environment than off-site disposal. Alternative 4 would not be protective of human health and the
environment due to it not being effective in reducing PCB concentrations in soil.
Compliance With ARAJRs
All alternatives, except No Action and In-Situ Bioremediation, have the potential to comply with
applicable or relevant and appropriate requirements (ARARs) as listed in Section 5.1.2. However, the
off-site alternative (e.g. disposal) must be performed at a permitted facility and on-site treatment will
have to meet applicable storage and treatment standards. All alternatives applying excavation would
meet air quality requirements for dust emissions. Alternative 4 would not comply with ARARs due to it
not being effective in reducing PCB concentrations in soil.
January 1997
4-5
OU 3 Record of Decision, Final
-------
4.4.2 Balancing Criteria
Long-Term Effectiveness
The on-site treatment and off-site disposal alternatives would be more effective in the long term
because the contaminants are destroyed or removed. Capping and disposal would not be as effective in
the long term because the contaminants continue to exist, and management controls would have to be
used to maintain effectiveness. The cap would require routine maintenance and inspection. In-situ
bioremediation would not be effective in the long term.
Reduction of Toxicity, Mobility, and Volume Through Treatment
Only the on-site treatment alternative, Alternative 5, would reduce the toxicity, mobility, and
volume of contaminants through treatment. The in-situ bioremediation alternative would not reduce the
toxicity, mobility, or volume of contaminants because it is not effective (based on the treatability study).
No other alternative includes treatment.
Short-Term Effectiveness
The capping alternative would be very effective in protecting human health in the short term. No
action does not create short-term exposure threats; however, there would be no short-term benefit to
human health or the environment. The other alternatives could create short-term exposure risks through
excavation, but these risks can be mitigated through dust control procedures. The transport of
contaminated soil could create an impact in the event of an accident or any spillage. In-situ
bioremediation would not be effective in protecting human health.
Implementability
The alternatives can be implemented relatively quickly. The capping alternative protects human
health and the environment in the shortest time frame. In addition, disposal sites are not available in
Alaska but are available outside of Alaska in the continental Unites States. However, either of those
alternatives could be implemented in one field season. The in-situ bioremediation alternative can not be
effectively implemented at this site.
Costs
The No Action and Excavation and Off-Site Disposal alternatives have the lowest costs. Since
the In-Situ Bioremediation alternative is not effective in reducing contaminant concentrations, its cost
should not be considered. The Excavation and On-Site Treatment and Capping alternatives have the
highest costs. The capping alternative has a requirement for ongoing operation and maintenance for 30
years which results in a higher overall cost.
4.4.3 Modifying Criteria
State Acceptance
The State of Alaska accepted the in-situ bioremediation alternative, as identified in the Proposed
Plan, with the contingency to implement one of the other alternatives if the treatment test is not
favorable. The results of the treatability testing show that in-situ bioremediation is not an acceptable
alternative for this site. As a result, the State of Alaska accepts excavation and off-site disposal as the
preferred alternative.
Community Acceptance
Based on the comments received during the public comment period, the public does not object to
the selected alternative. All of the remedial alternatives, with in-situ bioremediation as the preferred
OU 3 Record of Decision, Final 4-6 January 1997
-------
alternative, were presented to the public at the Restoration Advisory Board meeting held on July 12,
1995. The Air Force informed the public that one of the other alternatives would be selected in the event
that the in-situ bioremediation alternative did not prove to be effective in the treatability study. The
public did not object to any of the other alternatives. Part III of this ROD summarizes public input into
the selection process.
January 1997 4-7 OU 3 Record of Decision, Final
-------
[This page intentionally left blank.]
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Section 5.0
SELECTED REMEDY
The risks for soil at SD31, SD16, and Cherry Hill Ditch are considered acceptable and this
resulted in no further action decisions for the soil at SD31, SD16, and Cherry Hill Ditch. These sites are
available for unrestricted use. The presence of PCBs in the soil at SS21 results in an unacceptable risk
and the need for remedial action.
No current receptors exist for groundwater at the base due to institutional controls. As a
requirement of previously signed RODs for Elmendorf Air Force Base, institutional controls have been
established to restrict the use of the shallow aquifer in the outwash plain on the base. These restrictions
are enforced through the Base Comprehensive Plan. Projects and other activities are reviewed during the
planning stage to ensure compliance with the Base Comprehensive Plan. In addition, construction
projects and other activities also undergo an environmental review. This review helps ensure compliance
with groundwater use restrictions.
The selected remedy for the PCB contamination at SS21 is Alternative 3, Excavation and
Off-Site Disposal. This alternative best meets the nine CERCLA criteria. It is protective of human
health and the environment and complies with ARARs. It is effective at reducing contamination at SS21
in both the short and long term, and is implementable, cost-effective, and acceptable to the public and the
State of Alaska. This alternative provides an appropriate level of contaminant removal to reduce risks
and comply with ARARs.
The specific components of the selected remedy consist of the following:
To protect human health, a chain link fence will be used to temporarily restrict access to the
contaminated soil at SS21 until the soil has been removed and disposed off-site;
All soil with PCB concentrations in excess of 5 ppm will be excavated and shipped to a disposal
facility in the lower 48 which is acceptable for disposal of CERCLA waste under the Off-Site
Disposal Rule (40 CFR 300.440);
Confirmation sampling will be performed to ensure cleanup goals have been met;
The sampling and removal of PCB soils at SS21 is expected to be accomplished within one field
season; and
After cleanup, site SS21 soil will be available for unrestricted use. As a requirement of
previously signed RODs for Elmendorf Air Force Base, institutional controls have been
established to restrict the use of the shallow aquifer in the outwash plain on the base.
Alternative 3, Excavation and Off-Site Disposal was selected because it best provides the
following specific benefits at OU 3:
Excavation and off-site disposal of these soils will effectively remediate PCB-contaminated
surface soils to acceptable levels (<5 ppm);
The cleanup will be completed within one field season; and
January 1997 5-1 OU 3 Record of Decision, Final
-------
After the cleanup goals are met, the site will be available for unrestricted use.
5.1 Statutory Determinations
The selected remedy satisfies the requirements under Section 121 of CERCLA to:
Protect human health and the environment;
Comply with ARARs;
Be cost effective; and
Utilize permanent solutions and alternative treatment technologies to the maximum extent
practicable.
5.1.1 Protective of Human Health and the Environment
The selected remedy (excavation and off-site disposal) is protective of human health and the
environment. The current points of exposure are limited to surface soil and the risks are low. Controls
will protect against the potential of risk by assuring that the contaminated soils will not come in contact
with people until they have been removed for disposal.
The selected remedy of off-site disposal is protective because it will reduce PCB contamination
at the site to an acceptable level of risk.
5.1.2 Applicable or Relevant and Appropriate Requirements (ARARs)
The selected remedy will comply with all ARARs. The chemical-specific, action-specific, and
location-specific applicable or relevant and appropriate requirements (ARARs) are as follows.
Toxic Substances Control Act, 15 U.S.C. 2601 et seq.. and 40 CFR 761.60 and 761.75(b) is
applicable for the disposal of investigation derived waste from SS21. This is due to concrete with
PCB levels greater than 50 ppm;
Alaska Air Quality Control Regulation 18 ACC 50.050(0 >s applicable for the selected remedy
for dust suppression during the excavation of PCB impacted soil;
Treatment, Storage, Disposal Facility Requirements for Disposal of PCBs, 40 CFR 761, Subpart
D, is appropriate for the off site removal of PCB impacted soil from SS21; and
Off Site Disposal Rule, 40 CFR 300.440 is applicable for the transportation and disposal of PCB
soil from SS21.
The Safe Drinking Water Act is not an ARAR for this remedy since no further action is
necessary for groundwater under the OU 3 ROD. However, it is the ARAR for the groundwater actions
selected in the OU 5 ROD to protect groundwater receptors. If further action to protect groundwater is
ever necessary, it will be done pursuant to the OU 5 or OU 6 RODs.
5.1.3 Cost Effectiveness
The selected remedy is significantly less expensive that the other alternatives (other than No
Action). It affords overall effectiveness proportional to its costs. The on-site treatment alternative is not
OU 3 Record of Decision, Final 5-2 January 1997
-------
cost effective because it costs 450% more without increasing protectiveness. A summary of the cost for
each alternative is presented in Table 4-1.
5.1.4 Utilization of Permanent Solutions and Alternative Treatment Technologies to the
Maximum Extent Practicable
The USAF, the State of Alaska, and the USEPA have determined that the selected remedy
represents the maximum extent to which permanent solutions and treatment technologies can be used in
a cost-effective manner at OU 3. Of those alternatives that are protective of human health and the
environment and comply with ARARs, the USAF, the State of Alaska, and the USEPA have determined
that the selected remedy provides the best balance of tradeoffs in terms of long-term effectiveness and
permanence; reduction in toxicity, mobility, or volume achieved through treatment; short-term
effectiveness; implementability; cost; and the statutory preference for treatment as a principal element
and considering State and community acceptance.
The off site disposal alternative is by far the most cost effective alternative while providing a
good balance of short and long term efieciiveness relative to the other alternatives. The off site disposal
alternative does not utilize treatment, but the only effective treatment alternative for this site is very
costly and does not result in a significant reduction in risk relative to excavation and off site disposal.
5.1.5 Preference for Treatment as a Principal Element
Although the selected alternative for soil relies upon off-site disposal instead of on-site
treatment; the USAF, the State of Alaska, and the USEPA have determined that this remedy represents
the maximum extent to which permanent solutions and treatment technologies can be used in a cost
effective manner at OU 3. A treatability study for on site bioremediation was performed and the
technology was not shown to be successful. The on-site treatment alternative is not cost effective as it
would cost 450% more without increasing protectiveness.
5.2 Documentation of Significant Changes
Changes in this ROD from the Proposed Plan are discussed below. These changes are a logical
outgrowth of the OU 3 Proposed Plan. No other significant changes have been made.
The preferred alternative presented in the Proposed Plan (in-situ bioremediation) was found to be
ineffective at reducing PCB concentrations in the soil at SS21 and therefore cannot be the
selected alternative. The preferred alternative is excavation and off site disposal.
The contingency alternative in the Proposed Plan was on site treatment of the PCB contaminated
soil. The additional sampling conducted at SS21 in 1996 further defined the area impacted by
PCBs. This lead to a lower cost for the alternative of excavation and off site disposal. This
resulted in this alternative being chosen instead of on site treatment.
The description of the selected alternative (Excavation and Off-Site Disposal) in the Proposed
Plan included excavation and stockpiling of the entire area at SS21 (640 cubic yards). The
additional sampling conducted at SS21 in 1996 further defined the area impacted by PCBs. The
revised alternative is more cost effective and more protective of human health and the
environment by reducing the volume of soil to be excavated and sent for off-site disposal from
640 to 200 cubic yards and eliminates the need for on-site stockpiles.
The Proposed Plan noted a cleanup goal of 1 ppm PCBs. This was based on EPA superfund
guidance for PCB impacted soil. In order to determine a site specific cleanup level for PCBs at
January 1997 5-3 OU 3 Record of Decision, Final
-------
SS21, a risk evaluation was performed on the PCB soil. Using site conditions, a cleanup level of
5 ppm PCBs was determined to be comparable to the EPA standard default risk of 1 ppm. This
means that if SS21 contains less than 5 ppm PCBs, the site will be available for unrestricted use.
The cleanup level for PCBs at SS21 will be 5 ppm PCBs as specified in Section 5.0 of this ROD.
OU 3 Record of Decision, Final 5-4 January 1997
-------
APPENDIX A
OU 3 Administrative Record Index
-------
[This page intentionally left blank.]
-------
w
Table A-l
Index to OU 3 Documents in Administrative Record
Date Submitted
08/30/93
09/27/94
10/03/94
01/21/94
07/01/93
07/01/93
07/01/93
07/01/93
07/01/93
03/01/95
03/01/95
03/01/95
03/01/9;
Document Number
025187-025289
044375
044376-044377
034253
023499-023782
023783-023912
023913-024277
024278-024393
024394-024517
045850-046468
046469-046499
046500-046553
046554-046821
Title/Subject
Confirmation Notice No. 8, Installation Restoration Program,
Remedial Investigation/Feasibility Study, Operable Unit 3
Correspondence From The Remedial Program Manager,
Elmendorf AFB, AK
Correspondence From U.S. EPA To Civil Engineering,
Elmendorf AFB, AK
Engineers Discover PCB's In Soil Taken From Cherry Hill Ditch
Management Plan, Operable Unit 3
Management Plan, Operable Unit 3, Appendix A, OU3 Field
Sampling Plan
Management Plan, Operable Unit 3, Appendix B, Quality
Assurance Project Plan
Management Plan, Operable Unit 3, Appendix C, Site Safety
And Health Plan
Management Plan, Operable Unit 3, Appendix D, Historical
Analytical Results, Risk Based Concentrations Calculations, And
Toxicity Assessments
Operable Unit 3 Remedial Investigation/Feasibility Study Report
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix A: Aquifer Test Data
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix B: Historical And Other Supporting Data
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix C: Background Data - Statistics
Author
USAF-ElmendorfAFB
USAF-ElmendorfAFB
United States Environmental
Protection Agency
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
o
C
o
s.
o
?
o
5>
5'
21
5°
-------
o
c
g
EL
o
>
O
n
o
Table A-l
(Continued)
Date Submitted
03/01/95
03/01/95
03/01/95
03/01/95
03/01/95
03/01/95
03/01/95
03/01/95
03/01/95
03/01/95
03/01/95
03/01/95
Document Number
046822-046829
046830-047032
047033-047170
047 17 1-04723 8
047239-047326
047837-047336
047337-047368
047369-047396
047397-047406
047407-047436
047437-047700
047701-048018
Title/Subject
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix D: Fate & Transport
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix E: Seismic Data - Geophysical
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix F: QA/QC Results Summary
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix G: Field QC Data
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix H: Field Logs (Soil Boring Logs, Groundwater
Monitoring Well Logs)
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix I: Geotechnical Results
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix J: Chemistry Appendix
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix K: Groundwater Monitoring Well Completion Logs
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix L: Survey Data
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix M: Waste Management Appendix
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix N: Risk Assessment Tables
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix O: Field Log Location Forms
Author
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
69
-------
§
I
i
Table A-l
(Continued)
Date Submitted
03/01/95
03/01/95
03/01/95
03/01/95
03/01/95
03/01/95
03/01/95
03/01/95
03/01/95
06/15/95
9/16/96
9/96
9/96
Document Number
048019-048126
048127-048149
048150-048779
048780-04806
048807-049743
049744-049977
049978-050025
050026-052131
052132-052543
052670-052685
062053-062065
062066-062083
062084-062086
Title/Subject
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix P: Well Development Logs
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix Q: Base Water Study Data
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix R: Laboratory Data
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix S: Reconstruction of Cherry Hill Ditch
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix T: Sample Logs
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix U: Chain Of Custody Records
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Appendix V: Cost Detail And Cost Sensitivity Backup
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Attachment To Appendix F
Operable Unit 3 Remedial Investigation/Feasibility Study Report,
Attachment To Appendix M
Elmendorf Air Force Base OU3, The Proposed Plan for Remedial
Action
Operable Unit 3 Record of Decision Comments
Response to Comments USEPA, Draft Final Record of Decision
ADEC Letter regarding Draft Final Record of Decision
Author
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USAF-ElmendorfAFB
USEPA
USAF-ElmendorfAFB
ADEC
O
8
o
a. i
o
"h
o|
re
o
Zo'
o'
2! I
69
-------
o
u»
if
o
a.
o
~>
a
0)
Table A-l
(Continued)
Date Submitted
9/96
9/96
6/95
9/96
Various
Document Number
062087-062090
062091-062095
062096
062097-062139
062140-062141
Title/Subject
Response to ADEC Comments, Draft Final Record of Decision
USAF Memo, Cost Estimates for OU 3 Alternatives
Public Written Comment, OU 3 Proposed Plan
SS2I Biotreatability Testing of PCB-Contaminated Materials,
Final Report
Public Notices for OU 3
Author
USAF-ElmendorfAFB
USAF-ElmendorfAFB
Public
USAF-ElmendorfAFB
USAF-ElmendorfAFB
-------
APPENDIX B
COPCs in Soil and Groundwater
-------
[This page intentionally left blank.]
-------
W
3
Table B-l
Contaminants of Potential Concern (COPCs) in Soil Evaluated in the OU 3 Risk Assessment
Inorganic Analytes
Organic Analytes
SUS2
Surface Soils
Arsenic
Calcium
Chromium
Copper
Lead
Magnesium
Manganese
Molybdenum
Nickel
Potassium
Selenium
Zinc
1 ,2,4-Trichlurobenzene
2-Melhylnaphthalene
4-Methylphenol
4,4'-DDD
4,4'-DDE
4,4'-DDT
Acenaphthylene
Acenaphthene
Aldrin
Anthracene
Benzo(a)anlhracene
Benzo(a)pyrene
Bcnzo(b)fluoranthene
Benzo(g,h,i)perylene
Benzo(k)i1uoranlhene
Benzoic acid
Benzyl alcohol
bis(2-Ethylhexyl)phlhalate
Bulylbenzylphthalatc
Chrysene
Uibenz(a,h)anthracene
Dibenzofuran
Dieldrin
Diesel
Di-n-butyl phthalate
I-ndosulfan 1
Endosulfan 11
Endrin
Endrin aldehyde
Ethylbenzene
Fluoranthene
Fluorene
Heptachlor
Heptachlor epoxide
Hydrocarbons
lndeno( 1 ,2,3-cd)pyrene
Kerosene
Melhylene chloride
Naphthalene
PCB-1260
Phenanthrene
Phenol
Pyrene
Total Xylenes
gamma-BHC
della-BHC
alpha-BIIC
Subsurface Soils
Arsenic
Aluminum
Barium
Beryllium
Calcium
Cyanide
Lead
. Manganese
Molybdenum
Potassium
Selenium
Thallium
Vanadium
Zinc
4,4'-DDD
4,4'-DDE
4,4'-DDT
4-Methylphenol
Acetone
Benzo(a)anthracene
Benzoic acid
Benzo(g,h,i)perylene
2-Butanone (MEK)
Butylbenzylphthalate
Chlorobenzene
Dibulylphthalate
Heptachlor epoxide
Hydrocarbons
lndeno( 1 ,2,3-cd)pyrene
Methylene chloride
PCB-1260
Pyrene
Toluene
alpha-BHC
m & p-Xylene
West Intersource Area (MW24)
Subsurface Soils
Antimony
Arsenic
Lead
Molybdenum
Selenium
Thallium
Cyanide
Mercury
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthcne
Benzo(k)nuoranthene
Chrysene
Kluoranthcne
Phenanthrene
Pyrene
CD
O
73
n
o
O
3.
o
O
n
o
'
5'
«
21
5'
-------
o
u>
2?
S
5.
o
o
*
3
5'
Table B-l
(continued)
Inorganic Analytes
Organic Analytes
SD16
Surface Soils
Arsenic
Barium
Calcium
Chromium
Cobalt
Copper
Cyanide
Lead
M?gnesium
Manganese
Molybdenum
Nickel
Potassium
Selenium
Zinc
2-Methylnaphlhalene
4,4-DDD
4,4'-DDE
4,4'-DDT
Acenaphihene
Endrin
Benzoic acid
Accnaphlhylene
Acetone
Anthracene
Uenzo(a)anthracene
Benzo(a)pyrene
lleptachlorepoxide
Di-n-butyl phthalate
Benzu(b)fluoranthene
Benzu(g,h,i)perylene
Benzo(k)fluoranthene
Butylbenzylphthalate
Chrysene
Methylene chloride
bis(2-ethylhexyl)phthalate
Dibenz(a.h)anthracene
Dibenzofuran
Ethylbenzene
Fluoranthene
Fluorene
Toluene
delta-BHC
Indeno(l,2.3-cd)pyrene
Naphthalene
Phenanlhrene
Phenol
Pyrene
Xylenes
Subsurface Soils
Aluminum
Arsenic
Barium
Beryllium
Calcium
Copper
Lead
Molybdenum
Selenium
Silver
Vanadium
Zinc
Cyanide
2-Butanone (MEK)
2-Melhylnaphthalcnc
Acenaphthene
Anthracene
Benzo(a)anihracene
Benzo(a)pyrene
Bcnzo(b)fluoranthene
Benzoic acid
Benzo(g,h,i,)perylene
Benzo(k)fluoranthene
Butylbenzylphihalate
Chrysene
Dibenz(a,h)anthracene
Oibenzofuran
Di-n-bulylphthalale
Fluoranthcne
Fluorene
Gasoline
Hydrocarbons
lndeno( 1 ,2,3-cd)pyrene
Methylene chloride
Naphthalene
Phenanlhrene
Pyrene
Toluene
Trichloroethene
Xylene (total)
SS2I
Surface Soils
Arsenic
Calcium
Chromium
Copper
Cyanide
Lead
Manganese
Molybdenum
Nickel
Potassium
Selenium
Zinc
2-Methylnaphthalene
4,4'-DDD
4,4'-DDE
4.4'-DDT
Aldrin
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(g,h,i)perylene
Benzo(k)fluoranthene
Chrysene
Dibenz(a,h)anthracene
Dibenzofuran
Dieldrin
Di-n-butylphthalate
Endosulfan 1
Endosulfan II
Endrin
Fluoranlhene
Heptachlor
Heptachlor epoxide
Hydrocarbons
lndeno( 1 ,2,3-cd)pyrene
Naphthalene
PCB-IOI6
PCB-1260
Phenanlhrene
Pyrene
Toluene
Xylene (total)
gamma-BHC
CD
I
K)
-------
ta
fa
Table B-l
(continued)
Inorganic Anaiytes
Organic Anaiytes
SS2I
Subsurface Soils
Aluminum
Arsenic
Calcium
Copper
Cyanide
Lead
Molybdenum
Selenium
Vanadium
Zinc
1 ,2,4-Trichloroben/.ene
2-Methylnaphlhalenc
4,4'-DDD
4,4'-DDE
4,4'-DDT
Aldrin
Anthracene
Uenzo(a)anthracene
Benzo(a)pyrene
Dcnzo(b)fluoranthene
Benzo(g,h,i)perylene
Bcnzoic acid
Benzo(k)fluoranthene
Bulylbenzyl phthalate
C'hrysene
Kasl Intmourcc
Dibenzofuran
Dibutylphlhalate
Dieldrin
Hndosulfan 1
b'ndosulfan II
l:ndrin
l-ndrin aldehyde
Huoranlhcne
Area (MW2S)
Heptachlur
llcptachlor cpoxide
Hydrocarbons
lndeno( 1 ,2,3-cd)pyrene
Melhylene chloride
Naphthalene
PCB-IOI6
Phenanthrene
PCB-1260
Pyrene
Toluene
Trichloroethene
Xylene (total)
alpha-BHC
detta-BHC
Surface Soils
Antimony
Arsenic
Cyanide
Lead
Molybdenum
Selenium
Thallium
2-Methylnaphlhalene
Anthracene
Benzo(a)anthracene
Uenzo(a)pyrene
Benzu(b)fluoranthene
Benzo(g,h,i,)perylene
Bcn/o(k)fluoranthenc
Chrysene
Dibutylphlhalate
Fluoranthcne
Indcno( 1 ,2,3-cd)pyrene
Naphthalene
Phenanlhrene
Pyrene (3
00
I
ui
O
C
o.
2,
D
n
o_
55'
5'
I'
-------
o
Table B-2
o
3.
§
Contaminants of Potential Concern (COPCs) in Ground water Evaluated in the OU 3 Risk Assessment
Inorganic Analytes
Organic Analytes
Oil 3 West Groundwiter Area
Aluminum Potassium
Cadmium Vanadium
1,1,2-Trichloroethane
1 , 1 -Dichloroelhene
2-Hexanone
4-Mc(hyl-2-pentanone (MIBK)
Ikn/ene
Carbon tctrachloride
Chloroform
Chloromethane
Elhylbenzene
bis(2-Elhylhcxyl)phthalate
Trichloroethene
Trichtorofluoromethanc
Toluene
Xylene (total)
cis-l,2-Dichlorocthenc
cis- 1 ,3-Dichlorpropcne
Oil 3 East Groundwaler Area
Aluminum
Cadmium Potassium
Cyanide Vanadium
1,1,1 -Trichloroethane
1,1-Dichloroc thane
1 ,2-Dichlorocthanc
1 -Chlorohexane
Benzene
Carbon letrachloridc
Chloroform
Chloromethane
Diesel
Ethylbenzene
Fluorene
Tetrachlorocthcne
Toluene
Trichloroethene
Trichlorofluoromethane
Xylenes (total)
bis(2-
Ethylhexyl)phlhalate
cis- 1 ,2-Dichloroethene
cis-1 ,3-Dichloropropene
trans- 1 ,2-Dichloroelhenc
------- |