United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPNROD/R08-92/060
June 1992
PB93-964407
Superfund
Record of Decision:
&EPA
Ogden Defense Depot (Oper-
able Unit 1), UT
EPA Report Collection
Information Resource Center
U~ EPA Region 3
Philadelphia, PA 19107
Hazardous Waste Collection
information Resource Center
US .EPA Region 3
Philadelphia, PA 19107
u . S. Environmental Protection Agency
Region III Hazardous Waste
Technical Information Center'
84 1 Chestnut Street, 9th Flo(Q)U'
Philadelphia, PA 19107
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NOTICE
The appendices listed in the index that are not found in this document have been removed at the request of .
the issuing agency. They contain material which suppMMnent. but adds no fuf1her appkabte information to
the content of the document.. AU supplemental material is, however. eontBined in the administrative record
for this site.
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.
REPORT DOCUMENTATION 11. REPORT NO. I ~ 3. Recipient'a Acceaaion No.
PAGE EPA/ROD/R08-92/060
4. Tltla and Sublltla S. Report Date
SUPERFUND RECORD OF DECISION 06/26/92
Ogden Defense Depot (Operable Unit 1), UT
6.
Second Remedial Action - Subsequent to follow
7. Author(a) 8. Performing Organization RepL No.
8. Performing Orgalnlzatlon Name and Addre.. 10. ProjecllT..kJWork Unit No.
11. Contract(C) or Grant(G) No.
(C)
(G)
1~ Sponaorlng Organization Name and Addreu 13. Type 01 Report & Period Covered
U.S. Environmental Protection Agency 800/000
401 M Street, S.W.
Washington, D.C. 20460 14.
15. Supplementary Notea
PB93-964407
16. Abatract (Umlt: 200 worda)
Since 1941, the 1,100-acre Ogden Defense Depot (DDOU) site, located in Ogden, Weber
County, Utah, has been a key installation in the Department of Defense supply system.
Land use in the surrounding area is predominantly residential. In the past, both
liquid and solid materials have been disposed of at this site. Oily liquid materials
and combustible solvents were burned in pits, and solid materials were buried, burned,
or taken offsite for disposal. In 1979, the U.S. Army Toxic and Hazardous Materials
Agency (USATHMA) identified three locations on the DDOU where hazardous materials might
have been used, stored, treated, or disposed of. A USATHMA 1980 report then broke the
three locations into about 40 separate areas. Operable Unit 1, which is located in the
southwest part of the DDOU, is composed of the backfill material in the Plain City
Can a 1, Burial Site 1, and Burial Site 3-B. The Plain City Canal was an irrigation
canal that flowed between two branches of Mill Creek until it was backfilled from 1969
to 1973 with burning-pit debris from Burial Site 4-A. During 1988, a soil-gas survey
revealed that a portion of the Plain City Canal backfill was the apparent source of
elevated VOCs in the soil gas. Burial Site 1 was reported to have been used for the
disposal of riot control agent (chloroacetophenone) and white smoke (hexachloroethane)
(See Attached Page)
17. Document Analyaia L Deac,iptora
Record of Decision - Ogden Defense Depot (Operable Unit 1), UT
Second Remedial Action - Subsequent to follow
Contaminated Media: soil, debris, gw
Key Contaminants: VOCs (TCE), other organics (dioxins, pesticides), metals (arsenic,
b. IdentlfleralOpen-Ended Terma lead)
c. COSATI F1eIdlGroup
18. Availability Statement 19. Security Cia.. (This Report) 21. No. 01 Pagea
None 64
20. Security Cia.. (This Page) n Price
None
OPTIO 272 (4-77)
50272 101
(See ANSI Z38.18)
See Inst,uctlons on Reverse
(Formerty N'T1S-35)
Deportment 01 Commerce
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EPA/ROD/R08-92/060
ogden Defense Depot (Operable Unit 1), UT
Second Remedial Action - Subsequent to follow
Abstract (Continued)
containers in the 1940's. In the early 1960's, Burial Site 3-B was reportedly the
burying ground for over 1,000 arctic-style rubber boots. The DDOU, with concurrence from
the state and EPA, has elected to divide the site into four operable units. This ROD
addresses a final remedy for OU1 that will reduce the principal threats posed by
contaminated soil and shallow ground water at the site. The final remedy for OU2, which
addresses soil and ground water in the french drain area, the pesticide storage area, and
the parade ground area, is currently under construction. The primary contaminants of
concern affecting the soil, debris, and ground water are VOCs, including TCE; other
organics, including dioxins and pesticides; and metals, including arsenic and lead.
The selected remedial action for this site includes excavating and transporting
4,000 cubic yards of contaminated soil and debris offsite to a RCRA permitted hazardous
waste or industrial landfill; backfilling the area with clean fill; extracting and
treating contaminated ground water onsite using air stripping to remove contaminants,
adding a GAC system to the air stripper if dioxins and furans are detected in the
effluent at concentrations above the proposed MCL for dioxins and furans; transporting
wastes from the ground water treatment process, including any spent carbon offsite for
incineration, stabilization/fixation or disposal; recharging the aquifer with the treated
water using injection wells; monitoring air emissions; and monitoring ground water. The
estimated present worth cost for this remedial action is $2,200,000, which includes an
annual O&M cost of $146,000 for 7 years.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific soil clean-up goals are health-risk based and include dioxin
0.001 mg/kg; arsenic 35 mg/kg; zinc 1,500 mg/kg; and lead 500 mg/kg. Chemical-specific
ground water clean-up goals are also health-risk based and include cis-1,2-dichloroethene
70 ug/l; trichloroethene 5 ug/l; and vinyl chloride 2 ug/l.
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Defense Depot Ogden, Utah
--_.. -- .--------
..... .. -- --
Final
Record of Decision and
Responsiveness Summary
for Operable Unit 1
June 10, 1992
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FINAL RECORD OF DECISION
AND
RESPONSIVENESS SUMMARY
FOR OPERABLE UNIT 1
DEFENSE DEPOT OGDEN, UTAH
. This is a primary document of the DDOU RI/FS. It will be available in the Administrative
Record, which is maintained at the:
Weber County Library
2464 Jefferson Avenue
Ogden, Utah
Hours: . 10 am - 9 pm (Monday-Thursday)
10 am - 6 pm (Friday and Saturday)
FFASubmittalDate: JUDe 10, 1992
Actual Submittal Date: June 10, 1992
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Defense Depot Ogden, Utah
Operable. Unit 1
Declaration for the Record of Decision
. .--.------
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DDOU OPERABLE UNIT 1
DECLARATION
FOR THE
RECORD OF DECISION
Site Name and Location
Defense Depot Ogden, Utah
Ogden, Weber County, Utah
Operable Unit 1 - Burial Sites 1, 3-B, and the Plain City Canal Backfill
StAtPnv>nt of Basis and Purpose
This decision document presents the remedy for Defense Depot Ogden, Utah (DDOU)
Operable Unit 1 (OU 1) selected in accordance with the Comprehensive Environmental
Response, Compensation, and Liability Act of 1980 (CERCLA), as amended by the
Superfund Amendments and Reauthorization Act of 1986 (SARA) and, to the extent
practicable, the National Oil and Hazardous Substances Pollution Contingency Plan
(NCP). This decision is based on the Administrative Record for DDOU OU 1.
The State of Utah and the U.S. Environmental Protection Agency (EPA) concur on the
selected remedy presented in this Record of Decision (ROD). .
Assessment of the Site
Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this ROD, may present an imminent and
substantial endangerment to public health, welfare, and the environment.
~pUon of the Selected Remedy
Operable Unit 1 is one OffOUT operable units at the DDOU National Priority List (NPL) site
for which a remedial investigation/feasibility study (RIIFS) has been conducted. The role
of the OU 1 RIlFS is to investigate the nature and extent of contamination present at OU 1,
to investigate the principal threats to human health and the environment posed by those
contaminants, and to develop a remediation alternative for reducing those threats.
Operable Unit 1 is composed of Burial Sites 1, 3-B, and the backfill material in the Plain
City Canal. Burial Site 1 was reportedly used for t~e disposal of riot control agent
(chloroacetophenone) and white smoke (hexachloroethane) containers. Only non-toxic
materials were placed in Burial Site 3-B, including over 1,000 arctic-style rubber boots. Of
the three potential sources of contamination at OU 1, only the backfill in the Plain. City
Canal has been identified as a source of ground-water contamination. Backfill in the'
Plain ~ity Canal consists of glass, ash, charcoal, asphalt, partially burned plastic-coated
electrical wire, ~ood, concrete, plastic, and metal fragments mixed with silty sand and
gravel. .
In general, only semi-volatile organic contaminants, pesticides, polychlorinated
biphenyls (PCBs), dioxins, and furans were detected in the soil at au 1, and they are in the
localized area of the Plain City Canal. Volatile organic compounds evOCs) were not
detected in the Plain City Canal soils and debris.
The ground water in the shallow aquifer underlying OU 1 is contaminated by a variety of
VOC breakdown products including vinyl chloride and cis-1,2-dichloroethene (cis-1,2-
-1-
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DCE). The Plain City Canal soils and debris are considered the original source of these
contaminants. While the contaminants are no longer detectable in this material, traces of
contamination or hot spots may be present that were not located during the site
investigation.
Currently, there is no complete exposure pathway to contaminants present at OU 1.
However, future threats to human health and the environment at OU 1 include exposure to
PCBs, dioxins, and furans in the soil and debris of the Plain City Canal and the potential
for exposure to VOCs in the shallow groUnd water. The remedy will remove these potential
threats by excavating the contaminated soil and removing the ground-water contaminants
through treatment.
The selected remedy for DDOU OU 1 consists of the following:
.
Excavation and transport of contaminated soil and debris off site for disposal
in a RCRA permitted hazardous waste or industrial landfill.
.
Extraction of contaminated ground water, treatment by air stripping and
carbon adsorption, and reinjection into the shallow aquifer.
.
Monitor ground water to ensure the effectiveness of the ground-water treatment
alternative.
This alternative will control potential future exposures and risks associated with
contaminated soil in the Plain City Canal and in the shallow ground water.
Statutory De~..\: nAtinns
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
the remedial action, and is cost-effective. This remedy utilizes permanent solutions and
treatment technologies to the maximum extent practicable and satisfies the statutory
preference for remedies that employ treatment that reduces toxicity, mobility, or volume as
a principal element, with respect to the remediation of ground water. Because treatment of
soils was not found to be practicable, the disposal of soils off site does not satisfy the
statutory preference for treatment as a principal element. In order to ensure that ground-
water treatment continues to provide adequate protection of human health and the
environment, a review will be conducted by DDOU within five years after commencement
of the remedial action.
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UNITED ST TES ENVIRONMENTAL
::OTEcr{ AGENCY
Jack W. McGraw
At:: NG REGIONAL ADMINISTRATOR
.3.
Date:
6/2-6/9 Z
/ I
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STATE OF UTAH
DEP~NT OF HEALTH '1
By: rf1~f tfIt;/d'
Kenneth L. Alkema
EXECUTIVE DIRECTOR,
UTAH DEPARTMENT OF
ENVIRONMENTAL QUALITY
Date:
-4.
I,T(/~?~/~z
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::,FE~
. . Correll, CAPl'., US!,/,
COMMANDING OFFICER
.'
-5-
Date:
~hr,/7~
t- ~
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Defense Depot Ogden, Utah
Operable Unit 1
Decision Summary for the Record
of Decision .
-.----'
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TABLE OF CONTENTS
1.0 SITE NAME, LOCATION, AND DESCRIPI'ION
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
2.1 History .
2.2 Enforcement History
2.3 Investigation History
2.4 Community Relations History
2.5 Scope and Role of Operable Unit 1
3.0 SITE CHARACTERIZATION
3.1 Nature and Extent of Contamination
3.1.1 Nature and Extent of Soil Contamination
3.1.2 Nature and Extent of Ground-Water Contamination
3.2 Public Health and Environmental Impacts
3.2.1 Contaminant Identification
3.2.2. Exposure Assessment
3.2.3 Toxicity Assessmenf
3.2.4 Risk Characterization
3.2.5 Uncertainties
3.2.6 Summary of Site Risks
4.0 ALTERNATIVES EVALUATION
4.1 Development of Preliminary Alternatives
4.2 Initial Screening of Preliminary Alternatives
4.3 Description of Alternatives
4.3.1 Alternative 1 - No Action
4.3.2 Alternative 2 - Off-Site Landfill Disposal of Soil and
. Ground-Water Treatment by Air StrippinglGAC
4.3.3 Alternative 3 - Off-Site Soil Incineration and Ground-
Water Treatment by Air StrippinglGAC
4.3.4 Alternative 4 . Off-Site Landfill Disposal of Soil and
Ground-Water Treatment by Spray Aeration/GAC
4.3.5 Alternative 5 - Off-Site Soil Incineration and Ground-
Water Treatment by Spray AerationlGAC
4.4 Comparative Analysis of Remediation Alternatives
4.4.1 Overall Protection of Human Health and the Environment
4.4.2 Compliance with ARARs
4.4.3 . Long-Term Effectiveness and Permanence
4.4.4 Reduction in Mobility, Toxicity, and Volume Through
Treatment .
4.4.5 Short-Term Effectiveness
4.4.6 Implementability
4.4.7 Cost
4.4.8 State Acceptance
4.4.9 Community Acceptance
PAGE
1
2
2
2
3
3
4
4
4
4
5
5
6
6
7
7
8
8
8
8
10
13
13
13
13
15
16
16
17
18
18
19
19
19
19
19
2n
2n
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TabJe of Contents
5.0 SELECTED REMEDY
5.1 Description of the Selected Remedy
5.1.1 Remediation Goals
5.1.2 Costs
5.2 Statutory Detenninations
5.2.1 Protection of Human Health and the Environment
5.2.2 Compliance with Applicable or Relevant and Appropriate
Requirements
5.2.3 Chemical-Specific Requirements
5.2.4 Location-Specific Requirements
5.2.5 Action-Specific Requirements
5.2.6 To Be Considered Requirements
5.3 Cost Effectiveness
5.4 Utilization of PennanentSolutions
5.5 Preference for Treatment as a Principle Element
5.6 Documentation of No Significant Changes
APPENDIX A - SOIL AND GROUND-WATER REMEDIATION CRITERIA .
APPENDIX B - PERFORMANCE AND COMPLIANCE MONITORING PLAN
~
~
21
23
23
24
24
25
25
25
26
26
26
Z1
Z1
APPENDIX C - FEDERAL AND STATE CHEMICAL AND ACTION-SPECIFIC ARARs
ii
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1
2
3
4
A-I
A-2
FIGURE
NO.
1
2
Table of Contents
LIST OF TABLES
TABLE
NO.
TITLE
PAGE
Screening Summary for Soil Remediation Alternatives
Screening Summary for Ground-Water Remediation Alternatives
Comparative Evaluation of Alternatives
Alternative 2 - Off-Site Landfi)) Disposal of Soil and Ground-Water
Treatment by Air StrippingiGAC
11
12
14
22
Ground-Water Remediation Criteria Based on a Future Residential
Exposure Scenario
Soil Remediation Criteria Based on a Future Residential Exposure
Scenario
A-2
A.3
LIST OF FIGURES
TITLE
FOLLOWING
PAGE NO.
Location Map
VOCs Detected in Sha))ow Ground-Water Samples in the Vicinity of
Operable Unit 1
1
5
iii
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DDOU OPERABLE UNIT 1
DECISION SUMMARY
FOR THE
RECORD OF DECISION
1.0 SITE NAME, LOCATION, AND DESCRIPTION
Defense Depot Ogden, Utah (DDOU) is located at 1200 South Street and 500 West in the
northwest part of the City of Ogden, Weber County, Utah as depicted in Figure 1. The
DDOU facility has been a key instaHation in the Department of Defense (DOD) supply
system since September 15, 1941.
Situated in a semi-rural setting with the smaH commtinities of HarrisviHe (population
2,500) 1.5 miles to the north, Farr West (population 1,750) 3 miles to the northwest,
numerous smaH ranches and a few smaH businesses located to the west, east, and south,
DDOU covers approximately 1,100 acres within the Great Salt Lake Valley. Located
approximately 1.5 miles to the northwest is the Walquist Junior High School. A residential
area is located approximately one mile east of the Plain City Canal, but this is upgradient
of the source of ground-water contamination. The nearest off-Base residence is located.
about one-quarter mile to the west. Mill and Four-Mile Creeks flow east to west and drain
the topographicaHy flat area of the instaHation.
The Depot is underlain by unconsolidated lacustrine and alluvial deposits of Quaternary
and Recent age. An unused shallow water table aquifer, ranging in thickness from
approximately 20 to 30 feet, underlies Operable Unit 1 (OU 1). The shallow aquifer is
classified by the State of Utah as a Class II Aquifer a potential future source of drinking
water. Ground-water flow in the shallow aquifer underlying OU 1 is toward the northwest.
A deeper, confined aquifer has been encountered at a depth of approximately 110 to 125 feet
below the ground surface in the northern part of DDOU. Where encountered, this aquifer
exhibits artesian conditions with water levels in the wells rising above the ground surface.
Regional studies indicate that there may be some hydraulic connection between the
shallow and deep aquifers. The strong upward gradient that currently exists could
potentially change in the future as a result of excessive pumping of ground water from the
deeper aquifers.
In the past, both liquid and solid materials have been disposed of at DDOU. Oily liquid
materials and combustible solvents were burned in pits, and solid materials were buried,
burned, or taken off site for disposal. Several waste disposal areas have been identified on
property currently or formerly controlled by DDOU, and divided into four operable units.
Under the National Oil and Hazardous Substance Pollution Contingency Plan (NCP), "an
operable unit is a discrete part of a remedial action that can function independently as a
unit and contributes to preventing or minimizing a release or threat of a release." This
Record of Decision (ROD) addresses Operable Unit 1.
Operable Unit 1,- which is located in the southwest part of DDOU (Figure 1), is composed of
the backfill material in the Plain City Canal, Burial Site 1, and Burial Site 3-B. Analysis
of soil samples revealed that the soil in the Plain City Canal has been contaminated with
polychlorinated biphenyls (PCBs), dioxins, and furans.
-Analysis of ground-water samples from monitoring wells installed in the vicinity of OU 1
indicate that ground water in the shallow aquifer underlying OU 1 is contaminated with
volatile organic compounds (VOCs) including trichloroethene (TCE), cis-1,2-
dichloroethene (cis-l,2-DCE), and vinyl chloride (VCL). Of these contaminants, only VCL
and cis-1,2-DCE are widespread at OU 1, and only VCL and TCE exceed their maximum
-1-
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.. Warren !------...,
l~-
.;IJJ .
-
#...:- .~-
. /j' :-.-. DEFENSE DEPOT
"-'-" OGDEN BOUNDARY
.- .--- .._~
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: . .\
~.~-4d /' . i Wes~ Weber
Warren '-A~ ~.. 42' -----," '..... .'-'..
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. -
Scale in Feet
500
..
Burial Site 3-8
(OU 1)
Rubber boots
Burial Site 1 (OU 1)
Whlte smoke grenades
Burial Site 3-A(OU3)
Chemical warfare agent
Identification kits; .
chemical warfare agent
detection kits;
miscellaneous Items
Ogden
Nature Center
. .
I
i DDOU Fence line
IC_"~-----'--'k
EXPLANATION
. Operable Unit (OU) 1 burial areas
. Operable Unit (OU) 3 burial areas
, 't!:
. ,,,,',
t... .., "..."
LOCATION MAP
FIGURE 1
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contaminant levels (MCLs) of 2 micrograms per liter (~) and 5 J,.Lg/L, respectively. An
MCL is the maximum concentration of a contaminant permitted in public drinking water.
2.0 SITE HISTORY AND ENFORCEMENT ACI'1VlTIES
2.1 mSTORY
Burial Site 1. Located adjacent to the southwest comer of the Depot, Burial Site 1 lies
outside the existing DDOU property boundary (Figure 1). The land surrounding Burial
Site 1 is undeveloped and used by visitors to the Ogden Nature Center. A trench near the
center of Burial Site 1 was reported to have been used for the disposal of riot control agent
(chloroacetophenone) and white smoke (hexachloroethane) containers in about 1945. In
1985, a series of magnetic surveys located buried ferrous materials. A disturbed area was
identified near the central portion of the site. Field observations made during the 1985
study reported corroded 55-gallon drums and smaller canisters present on the ground
surface near the center of Burial Site 1, adjacent to the backfilled tTench. In addition, an
aerial photograph taken in 1958 shows a disturbed zone near the southwest comer of the site.
Burial Site 3.B. Burial Site 3-B (Figure 1), was reportedly the location of over 1,000 arctic-
style rubber boots buried during the early 19605. However, no evidence of these materials
was obtained from soil borings drilled in this area.
Plain City Canal Backfill. The Plain City Canal was an irrigation canal that flowed
northwest between two branches of Mill Creek until it was backfilled with burning-pit
debris from Burial Site 4-A during the period from 1969 to 1973. A soil-gas survey
conducted during the summer of 1988 revealed that a portion of the Plain City Canal
backfill was the apparent source of elevated VOCs in the soil gas. Soil borings drilled in
the Plain City Canal backfill revealed the presence of debris consisting of glass, ash,
charcoal, asphalt, partially burned plastic-coated electrical wire, wood, concrete, plastic,
and metal fragments. The debris is buried from 1 1/2 feet to 5 feet below ground surface in
a channel that is 20 feet wide. Figure 1 depicts the areal extent ofthe debris backfill.
2.2 ENFORCEMENT HISTORY
A records search in 1979 by the U.S. Army Toxic and Hazardous Materials Agency
identified three locations onDDOU where hazardous materials might have been used,
stored, treated, or disposed of. These locations were recommended for further study.
Defense Depot Ogden, Utah was proposed for inclusion on the National Priorities List
(NPL) in 1984 and the decision was finalized in July of 1987. As a result, the Defense
Logistics Agency (DLA) conducted a study to determine the location of any past disposal
sites and the potential for ground-water contamination resulting from those sites.
On June 30, 1986, DDOU entered into a Memorandum of Agreement with the State of Utah
Department of Health (UDOH) and the U.S. Environmental Protection Agency (EPA) to
undertake a remedial investigation/feasibility study (RIIFS) under the Installation
Restoratio~ Program.
In November of 1989, DDOU entered into a Federal Facility Agreement (FFA) with EPA
and UDOH. The propose of the agreement was to establish a procedural framework and
schedule for developing, implementing, and monitoring appropriate response {ictions at
DDOU in accordance with existing regulations. The FFA requires the submittal of several
primary and secondary documents for each of the four operable units at DDOU. This ROD
concludes all of the RIfFS requirements for OU 1.
-2-
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2.3 INVESTIGATION HISTORY
In 1981, ten shallow monitoring wells were installed at DDaU, including two wells in the
vicinity of au 1. Analysis of the ground water sampled from these wells indicated the
presence of vacs.
In 1985 and 1986, an investigation and evaluation of the hydrogeology and delineation of
hazardous waste disposal areas of the various DDaU sites was conducted. Four additional
monitoring wells and two soil borings were installed in the vicinity of au 1. Analysis of
the ground water san_pled from both sets of wells indicated the presence of vacs in
samples from two wells downgradient of the Plain City Canal. ..
Samples of surface water and sediment were taken from Mill Creek during the spring of
1985 to determine surface-water and sediment quality in the vicinity of au 1. A second set
of samples were taken in January of 1990. None of the contaminants detected exceeded
maximum contaminant levels in Mill Creek waters downstream of au 1, and
contaminants detected in sediment samples downstream of au 1 were detected at similar
levels in the off.Depot sampling point upstream of OU 1.
During the summer and fall of 1988, site characterization activities included a soil-gas
investigation, drilling and sampling of soil borings, installation of shallow monitoring
wells, and sampling and analysis of all monitoring wells installed at DDOU. A water
well survey was conducted and a list of potential human, plant, and animal receptors was
developed and used in the preparation of an endangerment assessment. In general,
results of the site characterization activities indicated the presence of vacs in the soil gas
and ground water underlying the site.
Further site characterization activities conducted during November and December of 1989
and January of 1990, included excavation and sampling of test pits, drilling and sampling
of additional shallow soil borings, and installation and sampling of additional shallow
ground-water monitoring wells. Results of this site characterization confirmed the
presence of vacs in the shallow ground water underlying OU 1. Vinyl chloride exceeded
the MCL in one sample. The only vac detected in soil samples was cis-1,2-dichloroethene,
which was found in one soil sample from below the water table. The detection of this
contaminant in soil was attributed to its presence in ground water at the same location.
Pesticides, PCBs, dioxins, and furans were also detected at low concentratio~s in test pit
soil samples from the Plain City Canal backfill material.
.Additional site characterization activities were conducted in July and August of 1990 with
the installation of more shallow ground-water monitoring wells and soil borings. Sample
analysis detected PCBs, dioxins, and furans in soil samples from the PlaiD City Canal
and VOCs were detected in shallow ground-water samples. .
Site cha,racterization activities, conducted in April of 1991 included installation and
sampling of soil borings in the Plain City Canal backfill and sampling of selected shallow
monitOring wells to determine the extent of contamination. No VOCs were detected in soil
samples -from th'e Plain City Canal, but pesticides were detected at concentrations similar
to those detected in background soil samples. Analytical results of ground-water samples
confirmed the presence and extent of VOC ground-water contamination at OU 1. .
2.4 COMMUNITY RELATIONS HISTORY
The RI/FS Report and the Proposed Plan for DDOU au 1 were released to the public on July
26, 1991 and October 3, 1991, respectively. These documents were made available to the
public in both the Administrative Record and an information repository maintained at the
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Weber County Library. The notice of availability for these two documents was published
in the Salt Lake Tribune, the Deseret News, and the Ogden Standard Examiner on October
3,4, and 5,1991.
A public comment period was held from October 3, 1991 through November 3, 1991 and a
public meeting was held on October 17, 1991 as part of the community relations plan for
OU 1. At the public meeting, representatives from DDOU, EPA, and the State of Utah
presented the preferred alternative and answered questions. A court reporter prepared a
transcript of the meeting. A copy of the transcript and all written comments received
du. jng the comment period have been placed in the Administrative Record. In addition,
copies of the transcript were sent to all of the meeting attendees who requested one. A
response to the comments received during this period is included in the Responsiveness
Summary, which is part of this ROD. This decision document presents the selected
remedial action for DDOU OU 1, chosen in accordance with CERCLA, as amended by
SARA and, to the extent practicable, the NCP. The decision on the selected remedy for this
site is based on the Administrative Record.
2.5 SCOPE AND ROLE OF OPERABLE UNIT 1
Defense Depot Ogden, Utah, with concurrence from the State of Utah and EPA, has elected to
divide the site into four operable units. The remedial actions planned at each of the four
operable units are, to the extent practicable, independent of one another. However, with
respect to OU 1 and OU 3, the close proximity of these two operable units has resulted in
some interrelationships between the remedial actions at each operable unit. For example,
a portion of Burial Site 3-A in OU 3 has been shown to be a source of ground-water
contamination. Therefore, this area will need to be cleaned up as part of the remedy for
au 3 to ensure that the remedy for au 1 can achieve the remediation goals selected.
The role of the remedial action for OU 1 is to reduce the principal threats posed by
contaminated soil and shallow ground water that may occur as a result of future exposure
of residents or on-Depot workers. This will be done by removing a source of VOC
contamination in soil and remediating contaminated shallow ground water for beneficial
use in the future. The remedy for OU 1 is the second final response action for the DDOU
site. The remedy for OU 2 is currently under construction.
3.0 SITE CHARACl'ERIZATION
3.1 NATURE AND EXTENT OF CONTAMINATION
3.1.1 Nature and Extent of Soil Conb1'll;nJltiOD
Plain City Canal. No VOCs have been detected in the Plain City Canal backfill, however
pesticides, PCBs, metals, dioxins, and furans have been detected. The pestjcides
dichlorodiphenyldichloroethane (DDD), dichlorodiphenyldichloroethene (DDE), and
dichlorodiphenyltrichloroethane (DDT) were detected in five samples at depths ranging
from about 1.5 to 6 feet at concentrations ranging from 0.006 to 1.9 milligramslk.ilogram
(mg/kg).. These-concentrations are consistent with pesticide concentrations detected at
other operable units at DDOU and appear to be related to the historic use of pesticides on
Depot. PCBs were detected in the backfill at two sample locations at depths between 3 and
10.5 feet at concentrations of 0.5 to 3.6 mg/kg. Four metals (lead, zinc, barium, and
cadmium) were detected in the Plain City Canal backfill at concentrations above
calculated background concentration for DDOU soils in uncontaminated areas. Of the
metals contaminants detected, lead and zinc were found most frequently. Lead
concentrations in the debris material ranged from 7.5 to 1,000 mglkg, compared to a
background concentration of 16 mglkg. Zinc concentrations in the debris material ranged
-4-
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from 37 to 11,000 mWkg, compared to a background concentration of 52 mg/kg. Extraction
Procedure (EP) toxicity metals analyses were performed on two samples coUected from the
backfill. Of the eight EP tOxicity metals, only barium and cadmium were detected in the
EP toxicity extract but at levels well below the EP toxicity limits for these elements.
Dioxin and furan isomers were detected in several samples from 1.0 to 6.5 feet below the
ground surface in the backfill. The concentrations of the dioxin and furan isomers
detected in the samples ranged from non-detection to 11,000 picograms per gram (pglg) or
parts per tril1ion. However, in terms of an equivalent concentration of
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), all the dioxin and furan isomers detected in
the most contaminated sample produced a concentration of only 0.026 parts per billion.
The volume of contaminated soil and debris in the Plain City Canal is estimated at 4,000
cubic yards, based on a length of approximately 1,200 feet, width of 20 feet, and
contaminated soil thickness of 4 feel
3.1.2 Nature and Extent of Ground-Water Contsnn;I'IAtiOD
. .
The distribution of VOCs detected in the shallow ground-water aquifer underlying OU 1 is
depicted in Figure 2. The major source of VOCs in ground water appears to be the Plain
City Canal backfill and Burial Site 3-A (part of OU 3). While no VOC contaminants have
been detected in the PCC backfill, contaminants may still be present at levels below the
detection limit OJ" in hot spots. The Burial Site 3-A source area will be remediated, if
necessary, under the remedy for Operable Unit 3. .
While the total VOC concentration in each monitoring well is generally less than 10 ~,
vinyl chloride and TCE were detected at concentrations exceeding their MCLs.
Trichloroethene was detected above its MCL of 5 IJ.gIL in only one sample from a
monitoring. well that is located in Burial Site 3-A. The most widespread VOCs detected in
the shallow ground water at OU 1 are vinyl chloride and cis-1,2-DCE, both of which are
degradation products of TCE. Of these two contaminants, only vinyl chloride was detected
at concentrations in excess of its MCL of 2~. The total areal extent of the zone of ground
water containing vinyl chloride at concentrations above 2 ~, as depicted on Figure 2, is
estimated to be 32 acres and the total volume of ground water within this area is estimated to
be approximately 56 million gallons. This estimate is based on the assumption that the
entire thickness of the aquifer is contaminated within the defined area. No evidence of a
dense non-aqueous phase liquid (DNAPL) was detected during monitoring of OU 1 ground
water.
During the July and August 1990 sampling round, dioxin and furan isomers were detected
in sediment-laden ground-water samples collected from monitoring wells located in the
Plain City Canal at concentration.s of up to 2,400 picograms per liter (pg/L) or parts per.
quadrillion. However, during the April 1991 sampling round, these contaminants were.
not detected in sediment-free ground-water samples. The earlier detection of the dioxins
and ~ans in the ground water has been attributed to adsorption of dioxins and £urans that
originated in ~e debris from the Plain City Canal, to silt and clay particles in the shallow
aquifer.
3.2 PUBLIC HEALTH AND ENVIRONMENTAL IMPACTS
A baseline risk assessment was conducted for OU 1 following completion of the site
characterization activities. The purpose of the assessment was to determine the most
significant contaminants present at OU 1, the different ways by which people, plants, and
animals would potentially come into contact with the contaminants, and the probability of
any harmful effects occurring as a result of that contact. Based on the results of the
-5-
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I r1 . il'l klJ:' LJ11 I~~ h LJ ~ . !i Ii i~~
~U:::ESE.'5 --':. r"J C::::j.j ~~ D , = ~
':"?i.::.".,."., CE:o.9. ::::::::i i "8" Ave.)' . ( t 1-------' ---:-,: . ! ~
"'''''''''..VCL:2 9 ---- " J ., \ .! ffi
JIIM-6 CDCE=51. .~L.",,"LmNm --- I'~ il
. J~~ i i ~. NA ~~~~ .''',:'~:~'~~;' :: J.M~~48u~__,- I W ~
'- . TDCE=4.8 CDCE= 26':;:Um::' \\ ""< \ r ii f:
. , ! - J~1.~.~~~LQ.6': J¥ii. 6 ) . [,D~\Jr
--~ Direction of Shallow 5 i 11 '''''', \ iH
. Ground-Water Flow ~ 5 i i "\.:~\
I ~III c" \~ I ~ £ I D r 1 \~\
Ogden" -"4- (~ x--+r-x x.......-. -" ; ~~.
Nature Center III ,,., e;.IJc,.,; \ . \~ i'::'::::-~3L.
"-x-- -'-.:E~E-12 -----,(-.-.- i
.JII~1. . .o~ '-.- f --;JM::~ III '
NA , III
"~I: . I~
~ . lil-
ONe.o' ~ ,,',
NA . r""""'''''''''''''': ':
EXPLANATION
. i II
. II
~.o.-
11I.JM~'7
IJ NA
@
o
,
, .
Scale in Feet
.
JM~23
TCE=8.5
500
,
i
i
i
Shallow monitoring well location
Well number
Analyte and concentration (~IL)
CDCE-cis-1.2-Dichloroethane
DCA-1.1 -Dichloroethane '
PCA-1.1 ,2.2- Tetrachloroethane
TCE- Trichloroethane
TDCE-Irans- 1 .2-Dichloroethene
VCl-Vinyl Chloride
NA-Not analyzed
ND-Notdetec:ted
. Concentration exceeding its maximum contaminant level (MCL).
Note: Samples were collected in April 1991 except JMM-59
which was sampled in July 1991.
VOCS DETECTED IN SHALLOW
GROUND-WATER SAMPLES IN THE
VICINITY OF OPERABLE UNIT 1
FIGURE 2
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baseline risk assessment, the media of concern for au 1 were detennined to be the ground
water underlying au 1 and the backfil1 within the Plain City Canal. Surface water was
not considered a medium of concern for au 1 because investigations of surface water and
sediments did not detect any contamination related to au 1 contaminants. In addition,
upstream and downstream concentrations of contaminants are similar.
The health risk assessment for au 1 indicates that there are no currently complete,
significant exposure pathways within au 1. However, contaminants in the Plain City
. Canal soil could pose a future risk to human health. If the contaminated shallow ground
water is used for domestic purposes in the futute, there would be a potential for carcinogenic
health effects. No current or future environmental effects are expected to occur as a result
of contaminants present at au 1.
3.2.1 Contaminant Identification
The initial step of the risk assessment was the selection of indicator chemicals. The
indicator chemical selection process used in the risk assessment was designed to focus on
those chemicals that are the most toxic and were anticipated to result in greatest human
exposure. An indicator chemical was selected based on the potential route of exposure and
the particular chemical's carcinogenic and non-carcinogenic toxicity. Specifically, the
indicator chemicals were selected on the basis of an index calculated as the product of their.
maximum measured concentrations in the medium of concern and their toxicity.
Toxicity was measured by the slope factor and the reciprocal of reference dose for
carcinogenic and non-carcinogenic health effects, respectively. The frequency of
detection was also included as a criterion for selection of ground-water indicator
chemicals. Indicator chemicals for carcinogenic health effects for soil and their
maximum concentrations were PCBs (3.6 mglkg), 2,3,7,8-TCDD (0.000026 mglkg),
arsenic (19 mglkg), cadmium (9.8 mg/kg), and chromium (39 mg/kg). Carcinogenic
indicator chemicals for ground water were 1,1-dichloroethene (1.8 ~), trichloroethene
(1.6 ~L), vinyl chloride (10 ~L), and 2,3,7,8-TCDD (0.00000092 J,J.g/L). Indicator
chemicals for non-carcinogenic health effects for soil and their maximum concentrations
were arsenic, barium (350 mg/kg), chromium, lead (1,000 mg/kg), nickel (57 mg/kg), and
zinc (11,000 mg/kg). Non-carcinogenic indicator chemicals for ground water were cis-
1,2-DCE (26 J,J.g/L) and vinyl chloride.
3.2.2 Exposure Assessment
No current exposure pathways were considered complete. A significant potential future
exposure to au 1 ground-water contaminants exists for off-site and on-site residents who
use shallow ground water from a well installed in the au 1 ground-water contaminant
plume, and could therefore ingest contaminants in drinking water, and inhale and
dermally adsorb contaminants in a shower. Future exposure to ground-water
contaminants could also occur for on-site residents who consume crops or livestock
exposed to contaminated water through the food chain. Future significant exposure
scenarios to soil could include exposure of construction workers to dioxins, furans, and
heavy metals during excavation activities in the Plain City Canal backfill. Not
quantita:tively evaluated, but potentially significant, would be the ingestion of soil by
future residents, especially children. Because the remedy for au I was not based on the
results of risk assessment, but rather upon ARARs for ground water and prevention of
future ground-water contamination for soil, chronic daily intake factors for each
contaminant for each exposure pathway are not presented here. However, the
contaminants of concern, their maximum concentration, and the associated risks for soil
and ground water at au 1 are presented in Tables A-I and A-2 of Appendix A
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3.2.3 Toxicity Assessment
Cancer slope factors have been developed for estimating excess lifetime cancer risks
associated with exposure to potentially carcinogenic chemicals. Reference doses have
been developed for indicating potential for adverse health effects from exposure to
chemicals exhibiting noncarcinogenic effects. All carcinogenic compounds had slope
factors except for PCBs, which did not have an inhalation slope factor for use in evaluating
the risk to construction workers from inhalation of contaminated dust. No reference doses
were available 'for lead; no inhalation reference doses were available for cis-l,2-DCE,
arsenic, cadmium, nickel, ur zinc. Because the remedy for au 1 was not based on the risk'
assessment, the values of reference doses and slope factors and their sources are not
presented here.
3.2.4 Risk Characterization
Excess lifetime cancer' risks (sometimes referred to as carcinogenic risks) are
determined by multiplying the intake by the cancer slope factor. These risks are
probabilities that are generally expressed in scientific notation (e.g., 1 x 10-6). An excess
lifetime cancer risk of 1 x 10-6 indicates that, as a plausible upper bound, an individual has
a one in a million chance of developing cancer as a result of chronic site-related exposure
to carcinogens over a 70-year lifetime under the specific exposure conditions at the site.
The target risk lev.el for a site is 1 x 10-6, although a value in the range of 1 x 10-4 to 1 x 10-6
may be acceptable. .
Potential concern for noncarcinogenic effects of a single contaminant in a single
medium is expressed as the hazard quotient. By adding the hazard quotient for all
contaminants within a medium and across all media to which a given population may
reasonably be exposed, a hazard index can be generated. A hazard index greater than 1
indicates that there may be a concern for potential health effects, while a hazard index less
than 1 indicates that the concern for potential health effects is quite low.
The potential carcinogenic risk to future off-site residents who use the shallow ground
water at the western boundary over a period of 30 years is on the order of 3 x 10-5. The total
hazard index for noncarcinogenic effects to future off-site .residents is on the order of 0.7.
The estimated carcinogenic risk to potential future on-site residents is on the order of
1 x 10-4, and the total hazard index is estimated as 2. These are significant risks. The
potential carcinogenic and non-carcinogenic risks to future construction workers who
become exposed to contaminated soils in the Plain City Canal over a period of two years are
7 x 10-6 and 0.8, indicating that the risks associated with this scenario may be, but are not
necessarily, acceptable. The use of contaminated irrigation water could lead to a cancer
risk of 3 xlO-7, which is insignificant. .
No significant environmental threats appear to be associated with au 1. The only area
where . ecological receptors could possibly come into contact with contaminants is through
the water and sediments of Mill Creek. However, because Mill Creek only flows part of the
year, it is a small area, and it is not a critical habitat for wildlife in the area. With the
exception of 1985 sampling results for antimony, concentrations of metals are similar in
samples taken upstream and downstream of au 1. This indicates a low potential for
impact on ecological receptors. Finally, because the contaminants associated with
disposal activities at au 1 have not been detected in surface water or sediments, it appears
that contamination at au 1 is not migrating to Mill Creek, and would not be expected to
have an impact on Mill Creek in the future.
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3.2.5 Uncertainties
The primary uncertainty associated with the exposure pathway of greatest concern,
ingestion of ground water by future on-site or off-site residents, is whether or not the
pathway will become complete in the future. A second uncertainty is associated with the
fact that all of the estimates of the total hazard index for exposure through ground water are
incomplete, and therefore low due to a lack of reference doses for some compounds.
Additional uncertainty is related to the assumption that contaminant concentrations will
remain constant with time and unknowns associated with dermal uptake of some
indicator chemicals. With respect to exposure to contaminated soil, there is uncertainty
associated with the estimate of dust inhalation and ingestion rates, and the bioavailability
of contaminants.
The potential for contaminant exposure by future residents through ingesting
contaminated soil was not evaluated. The risks for this exposure may be potentially
greater than were estimated for the construction worker scenario. However, because the
two scenarios involve the same parcel of contaminated soil, a remedy that addresses risks
to construction workers will also address potential risks to future residents.
3.2.6 Snnnnsl'l'Y of Site Risks
Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this ROD, may present an imminent and
substantial danger to public health, welfare, or the environment. There are no current
significant risks to human health and the environment from exposure to soil or ground
water at OU 1, nor are significant risks likely to develop in the future as long as the Depot
remains in existence. Under future residential site use conditions, risks may exceed
EPA's point of departure of one in one million excess lifetime cancer risk or a total hazard
index of one. In addition, the Plain City Canal backfill is a source of the contamination
detected in the shallow aquifer ground water.
4.0 ALTERNATIVES EVALUATION
As part of the DDOU OU 1 feasibility study, six soil and seven ground-water remedial
alternatives were developed. Under Section 121 of SARA, the selected remedial action
must be protective of human health and the environment, cost effective, and attain Federal
and State applicable or relevant and appropriate requirements
-------
2.
Institutional Controls - Legal and administrative actions would be
imposed to limit potential exposure under both current and future use
scenarios.
3.
Containment - Contaminant migration from soil to ground water would be
controlled by reducing infiltration after constructing an engineered cap
over the Plain City Canal backfill material and containment by a slurry
cut-off wall. Alternatively, the contaminated soil could be excavated and
placed in an on-site Resource Conservation and Recovery Act (RCRA)
hazardous waste landfill.
4.
Off-Site Soil Disposal - Contaminated soil would be excavated and
transported off site for incineration or for disposal in a RCRA permitted
hazardous waste or industrial landfill according to classification of the
soil and debris during excavation. .
5.
On-Site Soil Treatment - Contaminated soil would be excavated and treated
on site using chemical or incineration technologies. Treated soil would be
returned to the excavation if suitable or the residue would be disposed of off'-
site.
6.
In-Situ Soil Treatment - Contaminated soil would be immobilized in place
using soil vitrification technology.
Ground water contaminated by vinyl chloride is the principal threat posed by au 1.
Therefore, removal of vinyl chloride is the primary concern for ground-water
remediation. If dioxin and furan concentrations are detected at levels that produce a
health risk of greater than one in ten thousand, dioxins and furans will be removed from
the ground water by a granulated activated carbon (GAC) system.
As DDaU has four operable units currently undergoing RI/FS or remedial design
evaluations, the potential exists for consolidation or sharing of treatment facilities or
process options between operable units, especially when the nature of contamination is
similar between the areas. Shallow ground water beneath au 2, located less than one mile
from au 1, will be treated by air stripping and GAC. As some economy of scale may be
obtained by building only one treatment plant for ground-water remediation at the two
operable units, several alternatives were developed to investigate this possibility.
1.
. No Action - Ground-water monitoring would continue (this is an element
common. to all alternatives), but no. active remedial actions would be taken
to reduc'e the levels of contamination.
2.
Institutional Action - Legal and administrative actions would be imposed,
as necessary, to limit potential exposures under both the current and future
use scenarios. For example, steps would be taken to block out water rights
for down gradient areas to prevent the possible future use of shallow ground
water.
3.
Containment - Contaminant migration potential would be reduced by
controlling ground-water movement by installing upgradient subsurface
barriers at the southeast end of the vinyl chloride contaminant plume.
4.
Air StrippiDgiGAC at OU 1 with Recharge at OU 1 - Contaminated ground
water would be extracted through wells or trenches, treated by air stripping
and GAC, and reinjected into the aquifer at au 1.
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5.
Air Stripping/GAC at OU lIOU 2 with Recharge at OU 1 - Contaminated
ground water would be removed by wells or trenches, treated by air
stripping and GAC at a combined OU 1 and OU 2 treatment facility and
reinjected near OU 1.
6.
Air Stripping/GAC at OU lIOU 2 with Recharge at OU 2 - Contaminated
ground water would be removed by wells or trenches, treated by air
stripping and GAC at a combined OU 1 and OU 2 treatment facility and
reinjected at OU 2.
7.
Spray Aeration to Lined Pond FoDowed by GAC Treao-:,nt and Recharge at
OU 1 by Injection Wells or Trenches - Contaminated ground water would
be removed by wells or trenches, sprayed into a lined pond, pumped through
a GAC treatment system, and reinjected into the aquifer at OU 1.
4.2 INlTIAL SCREENING OF PRELIMINARY ALTERNATIVES
Preliminary alternatives were screened using three broad criteria: effectiveness,
implementability, and cost. The purpose of this screening was to reduce the number of
alternatives requiring detailed analysis. Comparisons were made among those
alternatives that offered similar functions or extent of remediation. The most promising
were compared in a detailed analysis. Tables 1 and 2 indicate how each alternative
compared with the three major criteria for soil and ground-water remediation,
respectively.
The end result of the screening process was a shortened list of alternatives that were
recommended for detailed analysis. The initial screening retained those alternatives
that appeared more effective, easier to implement, and less costly than other alternatives
offering a similar level of protection or extent of remediation.
Remediation alternatives were formulated by combining selected soil and ground-water
remediation alternatives. All of the remediation alternatives share continued monitoring
of ground-water quality as a common element. The remediation alternatives for OU 1 are
listed below:
Alternative 1 .
No Action
Alternative 2 .
Off-Site Landfill Disposal of Soil and Ground-Water
Treatment by Air Stripping/GAC
Alternative 3 -
Off-Site Soil Incineration and Ground-Water Treatment by Air
StrippinglGAC
Alternative 4 -
Off-Site Landfill Disposal of Soil and Ground-Water
Treatment by Spray Aeration/GAC
Alternative 5 -
Off-Site Soil Incineration and Ground.Water Treatment by
Spray Aeration/GAC.
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TABLE 1
SCREENING SUMMARY FOR SOIL REMEDIATION ALTEltNATIVES
AJten\8t1ve Etl'ectJveness ImplementabUity Cost Selected Comments
1. No Adlon I\xJr ExceUent Excellent Yes Represents besellne CMe for comporison. Does not prevent continued
. contamination 01 ground water.
2. Inslilullonal Controls I'oor ExcIJllcnt Excellent No Affords non-Invaslvc exposurc control. Docs not prevcnt continued
contaminalion of ground water.
3. Containment
Slurry Wall and Cap Fair Good Good No lligh maintcnance. Restricts future site usc.
. Landfill Good Good Good No Clcan closurc. Requires continued monitoring of landfill.
Restricts future slle use.
4. Off-Site SoU TreatmentIDlspoeal
. incineration £Keenent Pcxr Por Yu EUmlnates source, but cost Ia high.
. aeon d08UJ'& AooeptahIe &0 State'EPA because It Is the best
.... demonstrated available technology (8DA'l'). However, no lacility Is
';" currently pennI&ted lor dioxin destruction.
LandfUi Good Good Good Yes Ellml~tes a potentlal80urce. Clean closure. Assumes acceptable
wute cla.s8lficatlon 018OU.
6. On-Slle Soli Treatment
Dechlorination Good Fair Fair No Requires treatability study and Is an innovativc tcchnology.
Incineration Good I'oor Fair No I'ermilling may be dlmcul~ due to air emissions and dloxin/furan
content. No fadllty Is currcntly permilled for dioxin destruclion.
6. In-Situ Soli Treatment
. Vitrification Fair .'alr Fair No Questions regarding overall effcctlvcness of vltrlficalion process and
mlgralion of contaminants Into parlially vltrificd sol1a.
Not suitable for contaminant dcpths at OU 1. I'rcrondltionlng of soils
requ I red.
Note: 80ld Indlcatcs a sclected alternative.
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TABLE 2
SCREENING SUMMARY FOR GROUND-WATER REMEDIATION ALTERNATIVES
Alternative. Etrectiven- lmplementability Colt Selected
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4.3 DESCRIPI'ION OF ALTERNATIVES
4.3.1 Alternative 1 - No Action
Ground-water monitoring would continue (ground-water remedial Alternative 1), but no
active remedial actions would be taken to reduce the levels of ground-water contamination
or to remove the potential source of these contaminants in the soils of the Plain City Canal
(soil remedial Alternative 1). Therefore, Alternative 1 does not reduce the risk to human
health and the environment and a no-action alternative is not required to comply with
ARARs. The indirect, capital, operating and maintenance costs associated with this
alternative are presented in Table 3, as are estimates of present net worth costs based on a
20 year monitoring period and a statutory review every 5 years.
4.3.2
Alternative 2 - OfJ-Site Landfill Disposal of SOU and Ground-Water Treatment by
Air StrippinglGAC
After removing 1 to 2 feet of clean fill overlying the Plain City Canal backfill,
approximately 4,000 cubic yards of soil and debris in the Plain City Canal would be
excavated and transported to an off-site facility for placement in a RCRA hazardous waste
or industrial waste landfill, depending on RCRA classification of the soil and debris. .
While this material does not present a significant hazard to human health, excavation and
off-site landfill disposal would reduce the risk to the environment by removing the
potential source of vinyl chloride, dioxin, and luran contamination observed in the ground
water. Excavation would continue until soils remaining on site contain less than 25
mg/kg of PCBs, less than IlJ.g/kg total equivalent 2,3,7,8-TCDD, and present a health risk
of less than one in ten thousand, with a target of one in one million for the remaining
contaminants. The excavation would then be backfilled with clean fill. This alternative
would achieve clean closure of the source area. This cleanup action would take a few
months to complete and would be conducted approximately 15 months to two years after the
ROD is signed.
Because the concentrations of contaminants within the soils and debris in the Plain City
Canal are below the concentration levels that would remain after implementing the RCRA
treatment standards for FOOl through F005 listed wastes, land disposal would comply with
the applicable requirements ofRCRA land disposal restrictions (40 CFR part 268) and State
regulations (UAC Rule 450-101). All soil and debris removed from the Plain City Canal
will be presumed to contain FOOl through F005 listed wastes because of previous sampling
results and generator knowledge of disposal activities. Therefore, all soil is initially
destined to be disposed in a RCRA hazardous waste landfill and will be subject to LDRs.
However, if during sampling and analysis, as described in Appendix B of. the ROD,
contaminants in any soil samples are determined to be below the analytical detection
limits for the acceptable analytical methods for determining "F' listed wastes, that unit of
soil represented by the sample(s) will be considered to be outside of CERCLA jurisdiction
and may be taken to an industrial waste landfill. Also, if any other contauUnants that are
subje~ to LDRs, such as dioxins, are detected in the samples, the soils containing those
contaminants ~ll be subject to RCRA Subtitle C requirements. While not required under
CERCLA, disposal of soils that do not contain listed or characteristic hazardous wastes in a
RCRA industrial landfill is being undertaken by DDOU to remove the potential for this
material to act as a source of ground-water contamination at DDOU.
Ground water in the shallow. Class II aquifer at OU 1 would be extracted through a
sufficient number of wells to achieve a total flow rate of approximately 75 to 100 gallons per
minute. The number of wells required to achieve this flow rate would be determined by
pump testing extraction wells during installation. It has been estimated that
approximately 12 wells would be required to achieve this flow rate. Following extraction,
-13-
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TABLE 3
COMPARATIVE EVALUATION OF ALTERNATIVES
Evaluation Altematlve 1 Alternative 2 Alternative S Alternative 4 Alternative 5
Criteria NoAdJon Otf-Slte LandlUl DIsposal Otf-Slte SOU incineration Off-Site Landftll DblposaI Otf-Slte SoU incineration
of SOU and Ground.Wat8' and Ground-Water of SOU and Ground-Water and Ground-Water
Treatment by Air TrMtllumt by AIr Treatment by Spray Treatment by 9I-y
StripplnglGAC 88rippInWGAC AeraUonIGAC AeraUonIGAC
'J1Ire8Idd Criteria
1. Protectlvene88 0 . . .' .
2. ARARs A . . . .
Ba1ancinl Criteria
3. LO~II-Term Effectiveness A 0 . 0 .
4. Reduction of mobility, A 0 . 0 .
, toxicity, or volume
......
~
, 6. Short-Term Effectiveness 0 0 0 0
.
6. Implement ability . . A . A
7. Cost:
Present Worth(a) $254,000(11) *2,2~,OOO $16,010,000 $2,170,000 $14,970,000
Capital Costs $0 $I,3~,OOO $14,100,000 $1,300,000 $14,100,000
Operation snd Maintenance $18,600 $146,000 $146,000 $138,000 $138,000
Indirect Costs $0 $200,000 $200,000 $210,000 $210,000
ModIfyin, Criteria
8. State Acceptance A . . . .
9. Community Acceptance A . . .0 .
. Meets criterion (a) Assuming 6-year remediation time frame, except where noted.
0 Partially meets criterion (b) Assuming 20 years of monitoring.
A Does not meet criterion
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the ground water would be treated by air stripping and GAC, if necessary, and reinjected
into the aquifer around the perimeter of the vinyl chloride contamination plume.. A GAC
system would be added to the air stripper if dioxins and furans were detected in the effluent
at concentrations that produce a cancer risk of greater than one in ten thousand. The GAC
system would reduce the excess cancer risks to less than one in ten thousand with a target
of one in one miHion. Wastes from the ground-water treatment process would be
transported off site for incineration or land disposal depending on how the wastes are
classified under RCRA.
Ground-water remediation would be protective of the environment ana would eventuany
achieve Federal and State MCLs for vinyl chloride and TCE that are considered to be
ARARs. The area of attainment for these ARARs is defined by the areal extent of vinyl
chloride contamination above its MCL. This is an area of approximately 32 acres and
includes approximately 56 miHion ganons of ground water.
The time frame required for compliance with ground-water MCLs for vinyl chloride and
TCE is estimated to be a minimum of five years, assuming treatment of a minimum of
five pore volumes (approximately 280 million gallons) will be necessary to attain ARARs.
However, the ability of the pump and treat technology to achieve very low residuals (less
than 2 J.l.g/L for vinyl chloride) in ground water may be limited, as evidenced by EPA
experience with other sites where standard extraction systems are often not suitable for
removing all of the contaminants present in the aquifer material. Compliance with
ground-water cleanup criteria would be determined using selected compliance monitoring
wens. The treatment system would be operated until contaminant levels were maintained
beiow cleanup levels for one year. Monitoring would continue until the next scheduled
statutory 5-year review. If cleanup criteria were exceeded within this period, ground-water
treatment would recommence.
The air stripper vapor emissions are expected to be orders of magnitude less than the Utah
ARAR for air emissions which is 1.5 tons of total VOCs per year. The air stripper
emissions are not expected to exceed the emission concentration standard for vinyl
chloride (10 parts per million) of the National Emission Standards for Hazardous Air
ponutants (NESHAPS), as defined in 40 CFR Part 61 that are considered relevant and
appropriate. The disposal of any spent GAC would comply with the land disposal
restrictions ARARby testing the GAC to determine whether it contains VOCs above
treatment standards or other contaminants that may exhibit hazardous characteristics
under TCLP. If test results indicate that spent GAC contains VOCs above treatment
standards or exhibits hazardous characteristics, and treatment by fixation/stabilization
failed, it would be treated by incineration to meet treatment standards prior to disposal in a
RCRA hazardous waste landfill. The indirect, capital, operating and maintenance costs
associated with this alternative are presented in Table 3, as are estimates of present net
worth costs based on a 5-year remediation time frame and a statutory review every five
years.
This alternative, and those presented below, win not affect any endangered species or their
habitats. This .view has been confirmed through discussions with the Fish and Wildlife
Serviee.. The alternative win not affect any wetlands because there are none at DDOU or
in the vicinity that would be impacted by remedial actions.
4.3.3
Alternative 3 - Off-8ite Soil Incineration and Ground-Water Treatment by Air
StlippinWGAC
Contaminated soil (4,000 cubic yards) in the Plain City Canal would be excavated and
transported to an off-site RCRA permitted incineration facility. While not a significant
risk to human health, incineration of Plain City Canal soils would be protective of the
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environment by removing the source of vinyl chloride, dioxin, and furan contamination
observed in the ground water and achieving complete destruction of the soil contaminants.
Excavation would continue until soils remaining on site. contain less than 25 mg/kg of
PCBs, less than 1 ~g total equivalent 2,3,7,8-TCDD, and present a health risk of less
than one in ten thousand, with a target of one in one million for the remaining
contaminants. This remedial action would take a few months to complete and would be
conducted within 15 months to two years after the ROD is signed.
Because the soils in the Plain City Canal contain dioxins and furans, they must be
incinerated at a facility permitt.~d for dioxin destruction that is capable of achieving a
99.9999 percent destruction and removal efficiency. The Plain City Canal soils would be
incinerated and the waste residue disposed of in compliance with the FOOl listed waste
treatment standards. The treated debris would be monitored using TCLP extract for
compliance with FOOl listed waste treatment standards and to ensure that dioxin and furan
concentrations in the TCLP extract are less than 1 J.1g/kg for each of the tetra, penta, and
hexa-dioxin and furan isomers prior to land disposal. However, this is contingent on
identification of an incinerator permitted to receive and treat dioxin and furan
contaminated material. Currently, no such facility exists in the United States. Therefore,
implementation of this alternative is impossible at this time.
The method of ground-water remediation has been discussed under Alternative 2. The
indirect, capital, operating and maintenance costs associated with this alternative are
presented in Table 3, as are estimates of present net worth costs based on a 5-year
remediation time frame and a statutory review every five years.
4.3.4
Alternative 4 . OfJ-Site Landfill Disposal of Soil and Ground-Water Treatment by
Spray Aeration/GAC
Contaminated soil in the Plain City Canal would be excavated and transported to an off-
site facility for placement in a RCRA permitted hazardous waste or industrial landfill
depending on waste classification, as described in Alternative 2. Ground water would be
extracted from the shallow aquifer using wells, sprayed into a lined pond, pumped from the
pond through a GAC system, if necessary, and reinjected into the shallow aquifer along the
margin of the vinyl chloride plume. Wastes from the ground-water treatment process
would be transported off site for incineration or land disposal depending on how the wastes
are classified under RCRA. As the method of ground-water treatment differs from that
described under Alternative 2 only in the use of a spray aeration pond in place of an air
stripper, remediation times and ARARs compliance would be similar to those presented for
Alternative 2. Treatability testing would be required to evaluate the seasonal performance
of this system. The indirect, capital, operating and maintenance costs associated with this
alternative are presented in Table 3, as are estimates of present net worth costs based on a
20-year monitoring period and a statutory review every five years.
4.3.5
Alternative 5 . OfJ-Site Soil Incineration and Ground-Water Treatment by Spray
Aeration/GAC
Contaminated soil in the Plain City Canal would be excavated and transported to an off-
site incineration facility, as described in Alternative 3. Ground water would be extracted
from the shallow aquifer using wells or trenches, sprayed into a lined pond, pumped from
the pond through a GAC system, if necessary, to remove dioxins and furans and reinjected
into the shallow aquifer along the margin of the vinyl chloride plume, as described in
Alternative 4. Wastes from the ground-water treatment process would be transported off
site for incineration or land disposal, depending on how the wastes are classified. The
indirect, capital, operating and maintenance costs associated with this alternative are
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presented in Table 3, as are estimates of present net worth costs based on a 5-year
remediation time frame and a statutory review every five years.
4.4 COMPARATIVE ANALYSIS OF REMEDIATION ALTERNATIVES
During the detailed analysis of remediation alternatives for au 1, each alternative was
assessed against the nine evaluation criteria defined under the NCP. These criteria were
developed to address the technical and policy considerations that have proven important for
selecting among remedial alternatives and serve as a basis for the detailed analysis,
assessment, and the subsequent selection of an appropriate remedial action. In assessing
alternatives, all must meet criteria 1 and 2, which are the threshold criteria. . Those
alternatives satisfying the threshold criteria are compared using the five balancing
criteria. The final two modifying criteria can change the preferred alternative selected as
a result of applying the balancing criteria. The evaluation criteria are described below:
'111reshold Criteria
Threshold criteria used in the comparative analysis include overall protection of human
health and the environment and compliance with ARARs. These threshold criteria must
be met by an alternative before it can be evaluated under the five balancing criteria.
1.
Overall Protection of Human Health and the Environment - The
assessment against this criterion describes how the alternative, as a whole,
achieves and maintains protection of human heaIth and the environment.
2.
Compliance with .ARARs - The assessment against this criterion describes
how the alternative complies with ARARs or, if a waiver is required, how it
is justified. The assessment also addresses other information from
advisories, criteria, and the guidance that the parties have agreed is "to be
considered."
Rs.1S1ncin~ Criteria.
The five balancing criteria fonn the basis of the comparative analysis because they allow
tradeoff's among the alternatives involving different degrees of performance.
3.
Long-Term Effectiveness and Permanence - The assessment of
alternatives against this criterion evaluates the long-term effectiveness of
each alternative in protecting human health and the environment after the
response objectives have been met.
4.
Reduction of Mobility, Toxicity, and Volume Through Treatment - The
assessment against this criterion evaluates the anticipated performance of
the specific treatment technologies an alternative may employ.
5.
Short-Term Effectiveness - The assessment against this criterion
-examines the effectiveness of alternatives in protecting human health and
the environment during the construction and implementation of a remedy
and until the response objectives have been met.
6.
Implementability - The assessment against this criterion evaluates the
technical and administrative feasibility of the alternatives and the
availability of the goods and services needed to implement them.
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7.
Cost - The assessment against this criterion evaluates the capital, indirect,
and operation and maintenance costs of each alternative. Cost can only be
a deciding factor for alternatives equally protective of human health and
the environment.
Modifvinp' Criteria
8.
State Acceptance - This criterion reflects the State's preferences among or
concerns about alternatives.
9.
Community Acceptance - This criterion reflects the community's
preferences among or concerns about alternatives.
The results of the assessment of alternatives against the nine criteria were arrayed to
compare the alternatives and identify the key tradeoffs among them (Table 3). A
comparative analysis of the alternatives was then conducted to evaluate the alternatives
with respect to their relative performance according to the threshold and balancing
criteria. The objective of the comparison is to assess the relative advantages and
disadvantages among the alternatives. The results of this comparison are presented
below.
4.4.1 Overall Protection of Human Health and the Environment
Assuming that present land practices at DDOU remain unchanged, all of the remedial
alternatives presented in this detailed analysis would be equally protective of human
health and the environment because there are currently no exposure pathways to
contaminated soil or ground water at OU 1. Under all remedial alternatives except the no-
action alternative, the risks to human health due to exposure to contaminated soil would be
reduced because contaminated soils would be excavated and disposed of off site
(Alternatives 2 and 4) or incinerated (Alternatives 3 and 5). Under Alternative 1, the no
action alternative, lack of action may result in off-site migration of contaminated ground
water in the future. While there is currently no domestic or on-Depot use of the shallow
ground-water aquifer in the vicinity of OU 1, the future risk to the public would increase
under these conditions. All other alternatives would prevent off-Depot migration of the
ground water and would reduce risks associated with potential future use of on-Depot
shallow ground water. Therefore, Alternative 1 may fail to meet these criteria in the
future. Although Alternatives 2 and 4, which include off-site landfilling of Plain City
Canal soils, comply with this criterion, Alternatives 3 and 5, which result in the complete
destruction of contaminants in the soil and ground water, have the highest degree of
protectiveness.
4.4.2 Compliance with ARABs
Under Alternatives 2 and 4, Plain City Canal soils and debris that contain listed wastes or
exhibit the characteristics of a hazardous waste as defined by RCRA would be placed in a
RCRA hazardous waste landfill. Knowledge of the history of the Plain City Canal
materiaT indicates that the material may have once contained FOOl listed wastes, although
. testing to date indicates that this material does not contain RCRA listed wastes. However,
while not required under CERCLA, if the soils and debris from the Plain City Canal do not
contain a RCRA listed waste or exhibit the characteristics of a hazardous waste as defined
by RCRA, under Alternatives 2 and 4, they will be placed in a RCRA industrial landfill.
Incineration alternatives (Alternatives 3 and 5) would comply with ARARs if a 99.9999
percent destruction and removal efficiency incinerator permitted for dioxin and furan
destruction were available.
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The no action alternative (Alternative 1) would fail to meet ARARs for remediation of
ground water because vinyl chloride currently exceeds its MCL. However, the no~action
alternative is not required to comply with ARARs. All other alternatives would result in
eventual compliance with ARARs for ground water, given the 1imitations of pump and
treat technology. Although the time frame for compliance has been estimated as 5 years,
the actual cleanup time would depend on the response of the aquifer during remediation.
4.4.3 Long-Term Effectiveness and Permanence
The no action alternative would provide the least compliance with this criterion.
Alternatives 2 through 5 would comply with this criterion to some degree due to. the
remediation of the shallow aquifer that would occur under each. However, the permanence
of landfiIling of contaminated soils under Alternatives 2 and 4 rates lower than the
complete destruction by incineration that would be achieved in Alternatives 3 and 5.
Therefore, Alternatives 3 and 5 rate highest under this criterion.
4.4A Reduction in Mobility, Toxicity, and Volume Through Treatment
Alternative 1 rates lowest under this criterion because no action would be taken to
remediate contaminated soil and ground water. Alternatives 2 through 5 rate higher than
Alternative 1 due to the remediation of the shallow aquifer that would be achieved under
each. Alternatives 3 and 5 rate highest overall due to the complete destruction of
contaminants in the soil that would occur under those alternatives.
4.4.5. Short- Term Effectiveness
With the exception of Alternative 1, all of the alternatives compare equally under this
criterion. As no action would be taken under Alternative 1, there are no short-term risks to
be considered under current land use. An other alternatives involve similar risks created
by the methods that would be used to excavate and treat the contaminated soil and ground
water at au 1. These risks could be minimized by use of standard worker protective
equipment during the few months that excavation would occur. Risks due to ground-water
treatment would be limited to those associated with air-stripper emissions. These would be
minimized by compliance with NESHAPS and the State of Utah Clean Air Act, and the use
of emission control technology, if necessary.
4.4.6 Implementability
The no action alternative would be the easiest alternative to implement. Alternatives 2
and 4 would be easier to implement than Alternatives 3 and 5. Under Alternatives 3 and 5,
off-site soil incineration would require a facility permitted for destruction of dioxins and
furans. Therefore, implementation of these alternatives may not be possible because no
incineration facilities in the U.S. are currently permitted for thermal destruction of
dioxins and furans. The spray aeration/GAC remediation alternatives may require
limited. treatability studies because of reduced efficiency during winter months. Air-
stripping/GAC treatment of ground water under Alternatives 2 and 3 may be the easiest
ground-water treatment processes to implement technically because of readily available
prefabricated components. Therefore, Alternative 1 would be the easiest to implement,
followed by Alternative 2, Alternative 4, Alternative 3, and finally Alternative 5. .
4.4.7 Cost
The no action alternative (Alternative 1) has the lowest cost of all the alternatives
considered, with a present worth value of $255,000 (Table 3). Alternatives 2 and 4 both have
present worth values of approximately $2.2 million. Alternatives 3 and 5, both of which
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employ off-site soil incineration, are the most costly, with present worth values of
approximately $15 million each.
4.4.8 State Acceptance
The State has been involved in each step of the RIlFS process and the presentation of the
preferred alternative in the Proposed Plan for OU 1. Therefore, this criterion has been
addressed in the development of a remedy for OU 1. The State is supportive of the selected
remedy, but had a preference for off-site incineration of all soil and debris. However, as
stated under the description of alternatives that employ incineration, this is not currently
implementable.
4.4.9 CnnlWnlnlity Acceptance
Community acceptance is implicitly analyzed for the selected remedy in the
Responsiveness Summary at the end of this document. All comments received during the
public comment period have been addressed and the alternatives altered. Therefore, public
concerns regarding the selection of a remedy for OU 1 have been addressed.
5.0 SELECTED REMEDY
The selected remedy for DDOU Operable Unit 1 is Alternative 2, off-site landfill disposal
of soil and debris and on-site ground-water treatment using air stripping and, if
necessary, GAC. This remedy was presented as the preferred alternative in the Proposed
Plan for OU 1 and has the support of the State and EPA. Because the State has been
intimately involved in the RIlFS process at OU 1, State acceptance of the selected remedy
has been achieved through incorporation of State comments on primary documents
prepared in support of this ROD, and included in the Administrative Record. Community
acceptance of the selected remedy has been achieved through the Community Relations
Program, public meetings, and the public comment period. A detailed description of the
selected alternative, including the remediation goals, cleanup levels, and the costs
associated with each component of the remedy is presented in the following discussion.
5.1 DESCRIPTION OF THE SELECTED REMEDY
Under Alternative 2, backfilled soil and debris from the Plain City Canal will be
excavated and transported off site for landfill disposal at a RCRA permitted facility. All
soil and debris removed from the Plain City Canal will be presumed to be contaminated
with FOOl through F005 listed wastes because of the "Contained-in Rule" and previous
generator kDowledge of disposal activities. Therefore, all soil is initially destined to be
disposed in a RCRA hazardous waste landfill and will be subject to LDRS. However, if
during sampling and analysis, as described in Appendix B of the ROD, contaminants in
any soil sample are determined to be below the analytical detection limits for the acceptable
analytical methods for determining "F" listed wastes, that unit of soil represented by the
sample(s) will be considered to be outside of CERCLA jurisdiction and may be taken to an
industrial waste landfiU. Also, if any other contaminants that are subject to LDRs, such
. as dioxins, are detected in the samples, the soils containing those contaminants will be
subject to RCRA Subtitle C requirements.
The excavation - will be backfilled with clean soil, regraded, and revegetated. It is
estimated that removal of approximately 4,000 cubic yards of soil from the Plain City Canal
wiU eliminate contamination in this area.
Ground water will be extracted through approximately 12 extraction wells at a combined
flow rate of approximately 75 to 100 gallons per minute, and treated by air stripping to
remove contaminants. A GAC system will be added to the air stripper if dioxins and
furans are detected in the effluent at concentrations above the proposed MCL for dioxins
and furans of 5 x 10-5 J,1gIL. This concentration corresponds to a risk level of one in one ten
thousand. Exhaust air from the air stripper wiU be vented to the atmosphere, while treated
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water win be used to recharge the aquifer using injection wens. Air emissions from the
air stripper tower will be monitored to ensure compliance with the Utah Clean Air
regulatory limit of 1.5 tons of total vacs per year and the NESHAPS requirements for
vinyl chloride of 10 parts per million, using an in-stack monitoring point. If emission
levels threaten or exceed these criteria, air emission controls such as GAC or some other
technology will be employed to ensure compliance. Wastes from the ground-water
treatment process will be transported off-site for incineration or land disposal depending
upon how the wastes are classified under RCRA.
The ground-water treatment Systel" will be operated either continuously, by pulsing the
system, turning off individual wells, or pumping alternate wens to vary ground-water
flow patterns. Such measures win be taken to reduce the remediation time frame where
practicable whHe ensuring compliance with ground-water and air emissions ARARs.
The ground-water treatment system will be operated untH the remediation goals for
ground water outlined below have been met and maintained for one year in an compliance
monitoring wells. When contaminant concentrations have been maintained below.MCLs
for one year, the treatment system will be shut down .but compJiance monitoring will
continue untH the next scheduled statutory five-year review. If remediation goals are
exceeded during this time in any compliance monitoring wen, ground-water treatment
win recommence and this procedure will be repeated. If compliance is maintained until
the next scheduled statutory review, the remedy win be considered complete. Compliance
monitoring is discussed in more detail in Appendix B of this document.
During construction of the extraction and reinjection wens, a pumping test will be
conducted on each wen as it is completed. The number, spacing, and pumping rate of
extraction and injection wens win be adjusted according to the results of these tests. The
process components of this alternative and pertinent information and assumptions on
sizing, concentrations, flow rates, etc., are presented in Table 4. It should be noted that
some changes may be made to this remedy during the remedial design and construction
phases of the project.
5.1.1 Remediation Goals
The point of compliance for soil will be defined by the clean-up criteria described below.
The first of these criteria consists of removing all debris and visually contaminated soils
from the Plain City Canal. Visuany contaminated soil is defined as any soil containing
manufactured or processed material, plant or animal matter, or unnatural discoloration.
Samples will be collected from the soil in the walls and bottom of the excavation and
analyzed for VOCs, PCBs, dioxins, furans, and metals. These sample results will be used
to confirm that the soHs remaining in the excavation:
1.
Do not contain more than 25 mg/kg of PCBs, as recommended in EP A
Directive 9355.4-01FS.
2.
Do not contain dioxin and furan concentrations of more than 1 ~g total
equivalent 2,3,7,8-TCDD, as recommended by the Dioxin Advisory
Council.
3.
Do not contain other contaminants that would present an unacceptable
future health risk. Excavation will continue until a total carcinogenic
health risk of less than one in ten thousand is achieved in the soHs
remaining in the excavation. In addition, a target cleanup level of one in
one million has been adopted for au 1 and will be achieved wherever
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TABLE 4
ALTERNATIVE 2. OFF.SITE lANDFILL DISPOSAL OF SOIL AND
GROUND.WATER TREATMENT BY AIR STRIPPING/GAC
Ground Water
Soil
Eqx>sure Control
Exposure ContnJl
Eliminate exposure pathways through remediation
Eliminate exposure pathways by removing backfilled soil and debris
Extraction - Extraction WeDs
Extraction - Excavation
System of 12 wells
Individual well flow rates == 10 gpm :1:25%
Excavate approximately 4,000 cubic yards of contaminated soil
Transport contaminated soil off.site to RCRA permitted landfill
Backfill excavation with clean soil
Regrade and revegetate excavation site
Treatment - Air Stripping
,
N
N
,
Flow rate =120 gpm
Surge Tank = 5,000 gallons
Influent water temperature = 50. F
Influent vinyl chloride concentration = <10 I1glL
Effluent vinyl chloride concentration = < 211gIL
Vapor phase controls = None
Disposal
RCRA hazardous waste landfill for hazardous waste containing soils
RCRA industrial landfill for soils that don't contain hazardous
wastes
Treatment
Disposal- Reif\iection into ShaDow Aquifer
System of 12 injection well~
Individual well flow rates;: 10 gpm :1:25%
Stabilization/fixation if necessary for FOOl listed wastes
Incineration,if necessary, for dioxins and furans or other contami-
nants in soil and GAC
Ground.Water Treatment Costs (Includes Air Stripping and GAC)
Soil DisposallTreatment Costs (RCBA lIazardous Waste Landfill
Assumed)
Indirect = $52,000
Capita] = $288,000
Annual O&M = $146,000
Indirect = $150,000
Capita] = $1,030,000
Annual O&M = $0
Indirect costs include administration, engineering, and design
O&M costs include monitoring program costs
Indirect costs include soil analysis necessary for landfill disposal
Capital costs include excavation/transporVdisposal
-------
practicable. Similarly, excavation will continue until the hazard index for
noncarcinogenic contaminants remaining in the soil is less than one.
Contaminant concentrations associated with these health risks are
presented in Table A-2 in Appendix A, assuming a future resident exposure
scenario. Risk based cleanup levels are only defined for those
contaminants that do not have specifically defined cleanup levels.
During the excavation process, excavated soil and debris will be periodically tested using
. appropriate methods, including the Toxicity Characteristics Leaching Procedure (TCLP)
for compliance with treatment standards for FOOl listed waste, dioxins, and furans. These
tests will determine whether the excavated material must be placed in a RCRA hazardous
waste or industrial landfill, and whether any treatment will be necessary prior to
disposal.
The point of compliance for ground-water cleanup is defined by the area within the 2 J,J.g/L
contour for vinyl chloride. Cleanup levels for ground-water contaminants at au 1 are
listed in Table A-I in Appendix A. Ground water will be treated until contaminant
concentrations are below their MCLs in all au 1 ground-water compliance samples.
When these goals are met, the shallow ground water will be available for beneficial use.
However, the ability of pump and treat technology to achieve and maintain low
contaminant levels may be limited, as evidenced by experience at other sites.
A Performance and Ground-Water Compliance Monitoring Plan for soil and ground-
water remediation at au 1 is presented in Appendix B. This plan summarizes the
remediation goals, areas of attainment, restoration time frame, and the performance
standards for soil and ground-water remediation.
5.1.2 Costs
The costs associated with remediation of au 1 using Alternative 2 are listed in Table 4.
The total capital cost of the project is estimated at approximately $1,320,000. This includes
costs of installing a ground-water extraction and injection system, storage tank, an air-
stripping system, equipped with GAC if necessary, ground-water monitoring, excavation,
soil disposal at a RCRA permitted hazardous waste landfill, and reclamation of the site.
The disposal costs for a RCRA hazardous waste landfill have been used to assess disposal
costs. While some soil may be placed in a RCRA industrial landfill and the disposal costs
for this are approXimately 50 percent lower than a RCRA hazardous waste landfill, the
volume of soil that may be disposed of in this way will be dependent on results of sample
analyses during site remediation. Indirect costs for administration, engineering, and
design services were estimated to be approximately $200,000, while annual operation and
maintenance costs are estimated at $146,000. The present worth cost of the project, using a
five percent discount value, is estimated at $2.2 million, based on a 7-year duration of
treatment and monitoring.
5.2 STATUTORY DETERMINATIONS
The selected rem~dy for au 1 meets the statutory requirements of Section 121 of CERCLA as
amended by SARA. These statutory requirements include protection of human health and
the environment, compliance with ARARs, cost effectiveness, utilization of permanent
solutions and alternative treatment technologies to the maximum extent practicable, and
preference for treatment as a principal element. The manner in which the selected
r~medy for' au 1 meets each of these requirements is presented in the following discussion.
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5.2.1 Protection of Human Health and the Environment
The selected remedy for OU 1 protects human health and the environment through the
following engineering controls:
.
Excavation and removal of all backfilled soil and debris from the Plain City
Canal to comply with the cleanup criteria defined in Section 5.1.1., and
.
Extraction and treatment of all ground water until contaminant
concentrations are below their MCLs.
Removal of the contaminated soil and debris in the Plain City Canal will eliminate a
source of contamination in the ground water and remove the potential for exposure to these
contaminants in soil. Treatment of contaminated ground water at OU 1 to a level below the
MCLs will reduce the health risks to potential future ground-water users by approximately
two orders of magnitude. The selected remedy for soil and ground water at OU 1 will not
pose an unacceptable short-term risk and will have the effect of minimizing cross-media
impacts. This latter point will be achieved by ensuring compliance with Utah air
regulations and Federal requirements for vinyl chloride defined by NESHAPS.
5.2.2 Compliance with AppJicable or Relevant and Appropriate Requirements
Section 121(d)(1) of CERCLA as amended by SARA, requires that remedial actions must
attain a degree of cleanup that assures protection ofhurnan health and the environment. In
addition, remedial actions that leave any hazardous substances, pollutants, or
contaminants on site must, upon completion, meet a level 01' standard that at least attains
legally applicable or relevant and appropriate standards, requirements, limitations, or
criteria that are "applicable 01' relevant and appropriate requirements" (ARARs) under the
circumstances of the release. ARARs include Federal standards, requirements, criteria,
and limitations and any promulgated standards, requirements, criteria, or limitations
under State environmental or facility siting regulations that are more stringent than
Federal standards.
"Applicable" requirements are those cleanup standards, standards of control, and other
substantive environmental protection requirements, criteria, 01' limitations promulgated
under Federal 01' State law that specifically address a hazardous substance, pollutant or
contaminant, remedial action, location, or other circumstance at a remedial action site.
"Relevant arid appropriate" requirements are cleanup standards, standards of control,
and other substantive environmental protection requirements, criteria, 01' limitations
promulgated under Federal 01' State law that, while not "applicable" to a hazardous
substance, pollutant or contaminant, remedial action, location, or other circumstance at a
remedial action site, address problems or situations sufficiently similar to those
encountered at the site that their use is well-suited to the particular site.
In determining which requirements are relevant and appropriate, the criteria differ
depending on the type of requirement under consideration, i.e., chemical-specific,
location-specific; or action-specific. According to the NCP, chemical-specific ARARs are
usually health or risk-based numerical values that establish the acceptable amount or
concentratIon of a chemical that may remain in, or be discharged to, the ambient.
environment. Location-specific ARARs generally are restrictions placed upon the
concentration of hazardous substances or the conduct of activities solely because they are in
special locations. Some examples of special locations include floodplains, wetlands,
historic places, and sensitive ecosystems or habitats. Action-specific ARARs are usually
technology- or activity-based requirements or limitations on actions taken with respect to
hazardous wastes, or ,equirements to conduct certain actions to address particular
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circumstances at a site. Remedial alternatives that involve, for example, closure or
discharge or dredged or fill material may be subject to ARARs of RCRA and the Clean
Water Act.
The remedial action proposed, the hazardous substances present at the site, the physical
characteristics of the site, and the potential receptor population, were all considered when
determining which requirements are applicable or relevant and appropriate to the selected
remedy for OU 1. Federal and State laws, standards, requirements, criteria, and
limitations were reviewed for possible applicability to the OU 1 site. The only State
regulations identified that required more stringent requirbments than equivalent Federal
regulations were the source control requirements of UAC Rule 450-101 and the spill
reporting requirements of UAC Rule 450-9.
Through careful review of all applicable or relevant and appropriate public health and
environmental requirements of Federal of State laws, it has been determined' that the
remedy selected for OU 1 will meet these ARARs. Therefore, no SARA Section 121(d)(4)
waiver will be necessary. A brief discussion of how the selected remedy for OU 1 satisfies
the principal ARARs associated with the site is presented below.
5.2.3 Chemical-Specific Reqmrements
Chemical-specific ARARs set health- or risk-based concentration limits in various
environmental media. Ground-water quality ARARs for OU 1 are based on the Safe
Drinking Water Act maximum contaminant level (MCL), the maximum permissible
level of a contaminant in water that is delivered to any user of a public water system.
MCLs are generally relevant and appropriate as cleanup standards for contaminated
ground water that is or may be used for drinking. The State of Utah public drinking water
regulations are also relevant and appropriate to the au 1 selected remedy. In addition, the
Utah ground-water quality protection and air quality regulations are applicable to the site.
Other applicable or relevant and appropriate requirements include the NESHAPS
standards defined in the Clean Air Act, the Occupational Safety and Health
Administration (OSHA) regulations, and the Department of Transportation (DOT)
hazardous material transportation regulations. Potential Federal and State chemical-
specific ARARs are presented in Appendix C, Tables C-1 and C-2, respectively.
5.2.4 Location-Specific ReqWrements
Location-specific ARARs set restrictions on remediation activities, depending on the
location of a site or its immediate environs. The only location-specific ARAR associated
with the selected remedy for OU 1 is the EP A ground-water protection strategy that
establishes a ground-water classification system for protecting ground water based on its
value to society, use, and vulnerability. This strategy contributes to application of the
National Primary Drinking Water Standards as ARARs for the selected remedy. As
OU 1 is not located in a wetlands area or flood plain, is not a historic place, and the remedy
will not affect any historic place, endangered species or habitat, regulations pertaining to
these 'concerns are not ARARs.
,5.2.5 Action-Specific Requirements
Performance, design, or other action-specific requirements set controls or restrictions on
certain kinds of remedial activities related to management of hazardous substances,
pollutants, and contaminants. Federal action-specific ARARs that are relevant to the
remediation activities at OU 1 include Federal Underground Injection Control
Regulations, RCRA Land Disposal and Closure Regulations, and OSHA. State
requirements include the Utah State Engineer's regulations for well construction and
-25-
-------
pumping activities, the Utah Corrective Action Cleanup Standards PoHey for cleanup
levels, and the Utah Air Quality Regulations. Potential Federal and State action~specific
ARARs are presented in Tables C-3 and C-4 of Appendix C, respectively.
5.2.6 To Be Considered Requirements
In implementing the selected remedy for OU 1, DDOU has agreed to consider requirements
that are not legally binding. The only requirements to be considered (TBC) for the selected
remedy at OU 1 are the recommendations of the Dioxin Disposal Advisory Group
regarding pentach:.Jrophenol waste and dioxin and furan contamination and .EPA
Directive 9355.4-01FS that presents recommended cleanup levels for PCBs. This TBC is
included in the Federal chemical-specific ARARs presented in Table C-l.
5.3 COST EFFECTIVENESS
Overall cost-effectiveness can be defined as the reduction in threat to human health and the
environm.ent per dollars expended on a remedy. The selected remedy for OU 1 is the most
cost-effective alternative because it provides the maximum effectiveness proportional to
cost of any of the alternatives analyzed.
5.4 UTn.IZATION OF PERMANENT SOLUTIONS
This section briefly explains how the remedy provides the best balance of tradeoffs among
all the alternatives with respect to the five balancing criteria described in Section 4.4.
Implementability played an important part in the selection of Alternative 2 as a remedy.
Because the Plain City Canal soils contain dioxins and furans, alternatives that employed
incineration of soils to achieve the greatest reduction in mobility, toxicity, and volume
would be impossible to implement because an incinerator permitted for dioxin and furan
destruction is currently not available. Therefore, Alternatives 2 and 4 would be more
implementable than Alternatives 3 and 5. In addition, the proven technology employed for
ground-water remediation in Alternative 2, when compared to the use of surface
impoundments and the difficulties in assuring consistent seasonal performance under
Alternative 4, would make the technical implementation of Alternative 2 easier than
Alternative 4.
While less effective than alternatives that employed incineration of soils (Alternatives 3
and 5), the long-term effectiveness of Alternatives 2 and 4 would be similar because both
employ landfiIling of Plain City Canal soils. Because all alternatives would employ
treatment of gTound water by extraction and removal of vinyl chloride prior to reinjection,
they compared equally with respect to long term effectiveness for this media. .
The greates~ degree of reduction in mobility, toxicity, and volume, would be achieved by
. those alternatives that employ incineration treatment of soil (Alternatives 3 and 5).
However,. these alternatives cannot be implemented. Therefore, the ground-water
remediation tec;hnology was used to compare the remaining alternatives under this
criterion. Because both the air stripping and GAC treatment under Alternative 2 and the
surface impoundment and GAC treatment under Alternative 4 would effectively reduce
toxicity, mobility and volume of contaminants in ground water through treatment, both
compared equally under this criterion.
The short-term effectiveness of Alternatives 2 and 4- were also considered to be similar
because both would result in similar risks to the environment, community, and
remediation workers due to air emissions from the ground-water treatment process and
during excavation of soils. Finally, the cost of Alternative 2 was comparable to that of
-26-
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Alternative 4 and significantly lower than Alternatives 3 and 5. Therefore, Alternative 2
was selected as the remedy for OU 1 because it is an implementable and effective remedy
that achieves a reduction in the principal threat posed by the site in a cost effective manner.
5.5 PREFERENCE FOR TREATMENT AS A PRINCIPLE ELEMENT
The selected remedy for OU 1 utilizes permanent solutions and treatment technologies to
the maximum extent practicable. Treatment of soil will only be undertaken if necessary
to achieve compliance with land disposal restrictions under RCRA. The use of air
stripping and GAC to remediate contaminated ground water satisfies the statutory
preference for treatment and will reduce the principal threat of human ingestion or
inhalation of VOCs present in contaminated ground water underlying the site.
5.6 DOCUMENTATION OF NO SIGNIFICANT CHANGES
The Proposed Plan for OU 1 was released for public comment in October 1991 and
identified Alternative 2, Off-Site Landfill Disposal of Soil and Ground-Water Treatment
by Air StrippingiGAC, as the preferred alternative for remediation of this operable unit.
All written and verbal comments submitted during the comment period were reviewed.
The conclusion of this review was that no significant changes to the preferred alternative
were necessary prior to it becoming the selected remedy.
-27-
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APPENDIX A
SOIL AND GROUND-WATER REMEDIATION
CRITERIA
-------
APPENDIX A
son. AND GROUND-WATER REMEDIATION CRITERIA
This appendix describes the remediation criteria for soil and ground water at Operable
Unit 1 (OU 1). Criteria for ground-water contaminants must be met in each compliance
monitoring well. Confirmational soil samples will be collected after removing debris and
visibly contaminated soil from the Plain City Canal. Results of these sample analyses
will be used to confirm that all material contaminated above the cleanup levels hciS been
removed from the excavation. .
Ground-Water Remediation Criteria
Contaminants of concern for ground-water remediation for OU 1 include
cis-l,2-dichloroethene (cis-l,2-DCE), trichloroethene (TCE), and vinyl chloride. The
remediation criteria for these compounds are their respective drinking water maximum
contaminant levels (MCLs) of 70, 5, and 2 ~.
Table A-I summarizes the cleanup criteria for each contaminant of concern in ground
water, the potential cancer risk and hazard quotient associated with each contaminant at
current concentrations, and the potential cancer risk and hazard quotient associated with
each contaminant at the cleanup concentrations. These risks have been estimated
assuming future use of the ground water as a residential source of drinking and shower
water.
The cleanup criteria for 1,2-DCE and TCE are higher than the baseline concentrations of
these compounds. These criteria have been included because in some cases, samples from
individual wells have higher concentrations than the baseline concentration, which is
derived from an average concentration of several wells.
Soil Remediation Criteria
Contaminants of concern for soil remediation include arsenic, lead, zinc, PCBs, dioxins,
furans, cis-1,2-DCE, TCE, and vinyl chloride. The "to be considered" (TBC) remediation
criterion for PCBs of 25 mg/kg is based on EPA Directive 9355.4-01FS, "A Guide on
Remedial Actions at Superfund Sites with PCB Contamination." The TBC criterion for
dioxins and furans of 0.001 mg/kg was derived from the "General Approach Used by the
Dioxin Disposal Advisory Group (DDAG) Regarding Pentachlorophenol Waste (also
. PCBs)" by P. des Rosiers, November 1988. Remediation criteria for TCE and' vinyl
chloride of 490 and 3.2 mg/kg, respectively, correspond to cancer risks of 1 x 10-5 under a
future residential soil ingestion scenario. The remediation criteria for cis-1,2.DCE and
zinc are 70 and 1,500 mg/kg, respectively, which correspond to hazard quotients of 0.1
under this scenario. The criterion for arsenic of 35 mg/kg corresponds to a cancer risk of 1
x 1O-4~ An arsenic concentration that corresponds to a potential cancer risk of 1 x 10-5 (3.5
mg/kg) is not practical at OU I because that concentration would be below naturally
occurring background concentrations present at DDOU, whereas, the proposed criterion
can be clearly distinguished from background levels. There is no reference dose or slope
factor for lead, so a cleanup criterion corresponding to a hazard quotient of 0.1 or' a cancer
risk of 1 x 10-5 cannot be established. The criterion for lead of 500 mg/kg is a typical
remediation criterion for residential soils at CERCLA sites.
Risks for soil contaminants were calculated under a residential ingestion scenario where
a person was assumed to be exposed asa 15 kg child ingesting 200 mg of soil per day for six
years, and also as a 70 kg adult ingesting 100 mg of soil per day for 24 years. Table A-2
A-I
-------
TABLE A-I
GROUND-WATER REMEDIATION CRITERIA
BASED ON A FUTURE RESIDENTIAL EXPOSURE SCENARIO
Ccmcentl'ation Clean-Up
in Level(a) Clean-Up
Chemical J,1glLlBasis Base RiskIHQ (~) RiskIHQ
cis-1.2-Dichloroethene 5.3/RME NC/0.03 70 NC/0.4
Trichloroethene 0.5/RME 3 x 10-7/-(b) 5 3 x 1O-6/--(b)
Vinyl chloride 2.3/RME . 1 x 10-412 2 1 x 10-4/2
(a)
(b)
All cleanup levels are MCLs
No reference dose available to calculate the hazard Quotient
HQ Hazard Quotient
NC Noncal'cinogen
RME Reasonable maximum exposure concentration corresponding to the 95 percent
confidence interval of the mean
A-2
-------
TABLE A-2
SOIL REMEDIATION CRITERIA
BASED ON A FUTURE RESIDENTIAL EXPOSURE SCENARIO
Concentration Clean-Up
in Level Clean-Up
Chemical mg/kgIBasis Base Riak/HQ (mg/kg) RiskIHQ
cis-1,2-Dichloroethene ND NA 700 NC/0.1
Trichloroethene ND NA 490 1 x 1O-5/__(a)
Vinyl chloride ND NA 3.2 1 x 10-5/0.05
Arsenic 13/RME 4 x 10-5/0.2 35 1 x 10-4/0.5
Lead 460/RME --/-.< a) 500(b) --/-- ( a )
Zinc 4, 150/RME NC/0.3. 1,500 NC/0.1
PCBs 1.5/RME 2 x 1O-5/__(a) 25(c) 3 x lO-4/-(a)
2,3,7,8-TCDD (TEF) 0.OOOO28/RME 7 x 1O-6/__(a) 0.001(<:) 2 x lO-4/-.
-------
summarizes the remediation criteria, baseline risks, and post-remediation risks for soil
contaminants.
It should be noted that the criteria for most of the contaminants of concern for soil exceed
the baseline concentratiops detected in soil samples collected from the Plain City Canal.
While there is no risk-based reason for remediating the soil at au 1 for contaminants
other than zinc, remediation criteria are necessary should hot spots be encountered where
contaminant concentrations exceed previously detected concentrations.
A-4
-------
APPENDIX B
PERFORMANCEANDCOMPLMNCE
MONITORING PLAN
-------
APPENDIXB
PERFORMANCE AND COMPLIANCE MONITORING PLAN
PERFORMANCE AND COMPLIANCE MONITORING FOR REMOVAL OF PLAIN CITY
CANAL SOIL AND DEBRIS
Remediation Goals
Remediation goals for soil are defined in Section 5.1.1. of the ROD.
Area ofAtt-Ainment
The area of attainment for remediation goals is the backfill material in the Plain City
Canal (PCC) as depicted in Figure 1 of the ROD. This consists of a 1,250-foot length of the
canal, an assumed width of 20 feet, and contaminated soil and debris extending from
approximately 2 feet to 6 feet below the ground surface. The volume of soil and debris
requiring remediation is approximately 4,000 cubic yards. This estimate assumes the two
feet of clean fill overlying the contaminated material in the PCC will be replaced in the
excavation. Volume estimates may be revised during the Remedial Design/Remedial
Action (RD/RA) based on soil sampling results.
Restoration Time Frame
The restoration time frame for this action is estimated to be approximately six months after
commencement of work on site, and will be completed within 15 months to 21 months after
the ROD is signed.
Performance Standards
Specific performance standards used to ensure attainment of the remediation goals for soil
are:
.
Reduce contaminant concentrations in soils within the area of attainment to
comply with the remediation goals specified in Section 5.1.1. of the ROD.
Meet all ARARs identified in the ROD for soil.
.
.
The soil will be remediated in a timely manner in compliance with the selected
remedy presented in the ROD to achieve remediation goals as soon as
practicable.
Completion of~tion
Remediation shall be considered complete after the soil remediation goals have been
attained 'in. all samples taken from the perimeter of the excavation. Samples to be used for
compliance monitoring will be specified during Remedial Design (RD) in the
Performance and Compliance Sampling Program. Sample locations will be approved by
EPA and UDEQ during the RD. The number and location of samples to be taken may be
modified during remediation to. ensure compliance with remediation goals. The frequency
of sampling will be determined during the RD. Any statistical methods to average soil
concentrations areally or vertically shall be specified during the RD. The guidance
entitled "Methods for Evaluating the Attainment of Cleanup Standards-Volume 1. Soils
B-1
-------
and Solid Media" (EPA 230/02-89-042) will be consulted when establishing the Performance
and Compiiance Sampling Program.
Performance and Compliance Monitoring Program
A Performance and Compliance Monitoring Program (PCMP) will be implemented during
the remedial action to monitor performance and compliance with remediation goals. This
program will be developed during the RD and will include locations of performance
monitoring points within the PCC, frequency of monitoring, analytical parameters,
sampling methods, analytical methods, and b&.8tistical methods for evaluating data. The
PCMP will be included as part of the remedial design but may be modified during the
remedial action to account for changed conditions.
PERFORMANCE AND COMPLIANCE MONITORING FOR REMEDIATION OF
SHALLOW GROUND WATER
Remediation Goals
Remediation goals for shallow ground water are defined in Section 5.1.1. of the ROD.
Area of Attainment
The area of attainment for remediation goals is the volume of ground water containing
vinyl chloride above its MCL of 2~. The volume of contaminated ground water within
this plume is estimated at 56 million gallons.
Restoration Time Frame
The restoration time frame for this action is estimated to be approximately five years after
commencement of work on site.
Performance Standards
Specific performance standards used to ensure attainment of the remediation goals for
ground water are:
.
Reduce contaminant concentrations in ground water within the area of
attainment to comply with the remediation goals specified in Section 5.1.1. of the
ROD.
.
Meet all ARARs identified in the ROD for ground water.
.
The ground water will be remediated in a timely manner, in compliance with
the selected remedy presented in the ROD, to achieve remediation goals as soon
as practicable. . .
CompJetion ofRemecfiation
As described in Section 5.1 of the ROD, remediation of the ground water in the shallow
aquifer will be considered complete when contaminant concentrations have been
maintained below MCLs for a period of one year, whereupon the treatment system can be
turned off. Monitoring of compliance wells will continue until the next statutory five-year
review. If MCLs are exceeded within this time the treatment of ground water will
recommence. Compliance monitoring well locations will be specified during the remedial
design in the Performance and Compliance Monitoring Program and will be approved by
B-2
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EPA and UDEQ. The frequency of sampling may be modified during remediation to
ensure compliance with remediation goals but will not be less than that detailed in Section
5.1 of the ROD.
Performance and Compliance Monitoring Program
A Performance and Compliance Monitoring PTogram (PCMP) will be implemented during
the remedial action to monitor performance and compliance with remediation goals. This
program will be developed during the RD and will include locations of performance
monito. jng points within the vinyl chloride plume, frequency of monitonng, analytical
parameters, sampling methods, analytical methods, and statistical methods for evalUating
data. The PCMP will be designed to provide information that can be used to evaluate the
effectiveness of the selected remedy with respect to the following:
.
Horizontal and vertical extent of the plume
.
Contaminate concentration gradients
.
Rate and direction of contaminant migration
.
Changes in contaminant concentrations or distribution over time
.
Containment of the plume
.
Concentrations of contaminants in the treatment system influent and effluent.
The PCMP may be modified during the remedial action to account for changed conditions.
B-3
-------
APPENDIX C
FEDERAL AND STATE CHEMICAL AND
ACTION-SPECIFIC ARABs
-------
TABLE C-t
IDENTIFICATION OF FEDERAL CHEMICAL-SPECIFIC ARARs
Applicable!
Relevant
Standard, Requirement, and
Criteria. or Limitation Citation Description Appropriate Comment
Safe Drinking Water Act 42 use Sec. 300g
National Primary 40CFRPart 141 Established health-based N o/Y e s Remediation Goals:
Drinking Water standards for public water Vinyl Chloride - 2 ~g/L
Standards systems (maximum Trichloroethene - 5 ~g/L
contaminant levels).
(')
. National Primary 40 CFR Part 142 Establishes regulations for N o/Y e s Relevant and appropriate to remediation
.....
Drinking Water . the implementation and of ground water in the Class II aquifer
Regulations enforcement of 40 CFR Part underlying OU 1.
Implementation 141
National Secondary 40 CFR Part 143 Establishes welfare-based N o/N 0 Not applicable or relevant and appropriale
Drinking Water standards for public water to remediation of ground water in the
Standards systems (secondary Class II aquifer underlying OU 1 as these
maximum contaminant regulations control contaminants in
levels). drinking water that primarily affect the
aesthetic qualities. The treated ground
water will not be used as a water supply.
Maximum Contaminant Pub. L. No. 99-339, Establishes drinking water No/Yes Relevant and appropriate to remedialion
Level Goals 100 Stat. 642 (1986) quality goals set at levels of of ground water in the Class II aquifer
no known or anticipated underlying OU 1.
adverse health effects, with
an adequate margin of
safety.
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TABLE C-l
IDENTIFICATION OF FEDERAL CHEMICAL-SPECIFIC ARARs
(CONTINUED)
Applicable/
Relevant
Standard, Requirement, and
Criteria, or Limitation Citation Description Appropriate Comment
Clean Water Act 33 USC Sec. 1251-1376
Emuent Limitations 40 CFR Part 440 No/Yes Relevant and appropriate to remediation
. of ground water in the Class II aquifer
underlying OU 1.
() Water Quality Criteria 40 CFR Part 131 Sets criteria for water quality No/Yes Relevant and appropriate to remediation
,
t-:)
Quality Criteria for based on toxicity to aquatic of ground water in the Class II aquifer
Water, 1986 organisms and human underlying OU 1.
health.
Clean Air Act
National Primary and 40 CFR Part 50 Establishes standards for No/Yes Relevant and appropriate to anyon-site
Secondary Ambient Air ambient air quality to protect activity which might result. in air
Quality Standards public health and welfare emissions during remedial actions at
(including standards for OU 1.
part.iculate matter and lead).
National Emission 40 CFR Part 61 Sets emission standards for No/Yes Relevant and appropriate t.o emissions of
Standards for Hazardous designated hazardous vinyl chloride from the air st.ripper.
Pollutants pollutants
Occupational Safety and 20 USC Sec. 651-678 Regulat.es worker healt.h and Yes/--- Applicable to any activity carried out. as
Health Act safet.y. part of the remedy for OU 1.
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TABLE C-I
IDENTIFICATION OF FEDERAL CHEMICAL-SPECIFIC ARARs
(CONTINUED)
Standanl, Requirement,
Criteria. or Limitation
Citation
Comment
D.O.T. Hazardous Material 49 CFR Parts 107,
Transportation Regul8tiODS 171-177
(')
.
Co)
Resource Con8en'8tion imd
ReooveI'y Aft
Section 3004(m)
GeneralApprooch Used by
the Dioxin Disposal
Advisory Group (DDAG)
Reprding Pentachloro-
phenol Waste (also PCBs),
des Rosien (1988)
De8tription
Regulates transportation of
hazardous materials
Waives prohibition of land
disposal of a particular
hazardous waste if levels or
methods of treatment
substantially reduce toxicity
. or likelihood of migration of
hazardous constituents to
minimize short- and long-
term threats to human health
and the environment.
Recommends a site
evaluation method, cleanup
levels, and treatment
standards for sites known to
be PCB, copper wire/core
reclamation, or PCP wood
treating sites.
Applicable!
Relevant
and
Appropriate
Ves/---
No/Ves
N o/N 0
Applicable to remc!dial actions involving
off-Depot movement of hazardous
materials during remediation.
Appropriate for remedial alternatives
involving landfilling of contaminated
soil. .
To be considered. Site evaluation method,
cleanup levels, and treatment standards
for dioxins and furans.
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TABLE C-I
IDENTIFICATION OF FEDERAL CHEMICAL-SPECIFIC ARARs
(CONTINUED)
Standard, Requirement,
Criteria, or Limitation
Citation
Description
Applicable/
Relevant
and
Appropriate
Comment
A Guide on Remedial
Actions at Superfund Sites
with PCB Contamination
(')
J..
EPA Directive
9355.4-01FS
Summarizes pertinent
considerations in the
development and selection of
remedial actions. Provides
a general framework for
determining cleanup levels.
No/No
To be considered. Suggests cleanup levels
for PCBs on an industrial or residential
site.
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TABLE C-2
IDENTIFICATION OF STATE CHEMICAL-SPECIFIC ARARs
Applimble/
Relevant
Standard, Requirement, and
Criteria, or Limitation Citation Description Appropriate Comment
Utah Public Drinking Water Utah Admin. Code EstabHshes maximum No/Yes Requirements are relevant and
Regulations (U.A.C.) R449 contaminant levels for appropriate to au 1.
inorganic and organic
chemicals. Establishes
secondary drinking water
standards.
(')
I Utah Ground-Water Quality . Utah Admin. Code Establishes ground-water Yes/--- Applicable to the Class II aquifer
en
Protection Regulations R448-6 quality standards for the underlying au 1.
. different ground-water
aquifer classes.
Division of Solid and Title 19, Chapter 6, Corrective action clean-up Yes/--- Lists general criteria to be considered in
Hazardous Waste, U.C.A., Utah Admin. standards policy - RCRA, estabHshing clean-up standards.
Deportment m Code R450-101 UST, and CERCLA sites.
Environmental Quality
Department m Agriculture Title 4, Chapter 14, Pesticide control--safe and N olY e s See particularly R68-7-10, U.A.C.,
Utah Code Annotated appropriate use of pesticides. regarding storage, transport and disposal,
(U.C.A.) Utah and R68-7-11, U.A.C., regarding other
Admin. Code R68-7 unlawful acts.
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TABLE C-2
IDENTIFICATION OF STATE CHEMICAL-SPECIFIC ARAR8
(CONTINUED>
Standard. Requirement,
Criteria, or Limitation
Citation
Description
Applicable!
Relevant
and
Appropriate
Comment
Division of Water Quality
Departmentm
Environmental Quality
(")
,
01
Title 19, Chapter 5, Definitions for Water
U.C.A., Utah Admin. Pollution Rules and General
Code R448-1 U.A.C. Requirements.
Title 19, Chapter 5, Standards of Quality for
U.C.A., Utah Admin. Waters of the State.
Code R448-2
Yes/---
Yes/---
Applicable to remediation of ground water
at OU 1.
These rules are specific to Utah waters,
though they are derived in part by using
Federal criteria. See particularly the
anti-degradation policy in Utah Admin.
Code R448-2-3.
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TABLE C-3
IDENTIFICATION OF FEDERAL ACTION-SPECIFIC ARARs
Applicablel
Relevant
Standard, Requirement, and
Criteria, or Limitation Citation Description Appropriate Comment
Guidelines for the Land 40 CFR Part 241 Establishes requirements Y est u- Applicable to landfilling of soils that do
Disposal of.Solid Wastes and procedures for land not contain listed or characteristic
disposal of solid wastes. hazardous waste.
Criteria for 40 CFR Part 257 Establishes criteria for use Y est m Applicable to landfilling of soils that do
Classification of Solid in determining which solid not contain listed or characteristic
() Waste Disposal waste disposal facilities and hazardous waste.
.
-.:J Facilities and Practices practices pose a reasonable
probability of adverse effects
on health or the
environment.
Standards Applicable to 40 CFR Part 262 Establishes standards for Yes/m Applicable to remedial alternatives
Generators of Hazardous generators of hazardous involving landfilling of contaminated
Waste waste. soils.
Standards Applicable to 40 CFR Part 263 Establishes standards which Yes/m Transport of hazardous materials ofT-site
Transporters of apply to persons transporting may occur during some remedial
Hazardous Waste hazardous waste within the alternatives.
U.S. if the transportation
requires a manifest under 40
CFR Part 262.
-------
TABLE C-3
IDENTIFICATION OF FEDERAL ACTION-SPECIFIC ARARs
(CONTINUED) .
Standard, Requirement,
Criteria, or Limitation Citation
Standards for Owners 40 CFR Part 264
and Operators of
Hazardous Waste
Treatment, Storage, and
Disposal Facilities
(')
00
. General Facility Subpart B
Standards
. Preparedness and Subpart C
Prevention
. Contingency Plan Subpart D
and Emergency
Procedures
. Manifest System, Subpart E
Record Keeping, and
Reporting
Description
Applicable/
Relevant
and
Appropriate
Comment
See. discussion of specific subparts.
Establishes minimum
national standards which
define the acceptable
management of hazardous
waste for owners and
operators of facilities which
treat, store, or dispose of
hazardous waste.
Yes/---
Yes/---
Yes/---
Yes/---
Yes/...
Applicable to the landfill receiving OU 1
soils.
Applicable to the landfill receiving OU 1
soils.
Applicable to the landfill receiving OU 1
soils.
Applicable to the landfill receiving OU 1
soils.
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TABLE C-3
IDENTIFICATION OF FEDERAL ACTION-SP"~CIFIC ARARs
(CONTINUED) .
Applicablel
Relevant
Standard, Requirement, and
Criteria, or Limitation Citation Description Appropriate Comment
. Releases from Solid Subpart F Yes/m Applicable to the landfill receiving au 1
Waste Management soils.
Units
. Closure and Post- Subpart G Yes/--- Applicable to the landfill receiving au 1
() Closure soils.
cD
. Financial Subpart H Yes/--- Applicable to the landfill receiving au 1
Requirements soils.
. Use and Manage- Subpart I Yes/--- Applicable to the landfill receiving au 1
ment of Containers soils.
. Tanks Subpart J N o/N 0 No tank storage proposed.
. Surface Subpart K N o/N 0 No surface impoundments proposed.
Impoundments
. Waste Piles Subpart L N o/Y e s Relevant and appropriate to temporary on-
site stockpiling of soil.
. Land Treatment Subpart M No/No No land treatment proposed.
. LandfiJIs Subpart N Yes/--- Applicable to the landfill receiving au 1
soils.
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.TABLE C-3
IDENTIFICATION OF FEDERAL ACTION-SPECIFIC A.RARs
(CONTINUED)
Standard, Requirement.
Criteria, or Limitation
Citation
Description
Applicable/
Relevant
and
Appropriate
.
Incinerators
Comment
o
,
~
o
Interim Standards for
Owners and Operators of
New Hazardous Waste
Land Disposal Facilities
Land Disposal
Restrictions
Safe Drinking Water Act
Subpart 0
40 CFR part 267
Establishes minimum
national standards that
define acceptable
management of hazardous
waste for new land disposal
facilities.
Yes/---
N o/Y e s
Yes/Yes
N o/Y e s
Applicable if incineration destruction of
dioxin and furan contaminated soils is
necessary.
Remedies should be consistent with the
more stringent Part 264 standards as these
represent the ultimate RCRA compliance
standards and are consistent with
CERCLA's goal of long-term protection of
public health and welfare and the
environment.
Applicable to off-site landlilling of soils
containing listed hazardous waste.
Relevant and appropriate for dioxin and
furan treatment standards.
Relevant and appropriate to ground-water
treatment system monitoring.
40 CFR Part 268
Identifies hazardous wastes
that are restricted from land
disposal.
42 USC Sec. 300g
40 CFR Part 136
Sets approved test methods for
waste constituent
monitoring.
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TABLE C-3
IDENTIFICATION OF FEDERAL ACTION-SPECIFIC ARARs
(CONTINUED)
Applicable/
.Relevant
Standard, Requirement, and
Criteria, or Limitation Citation Description Appropriate Comment
Underground Injection 40 CFR Parts 144.47 Provides for protection of No/Yes Relevant and appropriate to on-site
Control Regulations underground sources of ground-water reinjection system.
drinking water.
Toxic Substances Control Act 15 use Sec. 2601-2629
<;1 PCB Requirements 40CFR 761 Disposal of waste material N o/Y e s Some PCBs detected in PCC soils. Only
~
~
. containing PCBs. appJicable if PCB concentrations greater
than 50 ppm are detected.
Occupational Safety and 20 use Sec. 651-678 Regulates worker health and Yes/--- Applicable to all actions associated with
Health Act safety. the remedial alternative for OU 1.
D.O.T. Hazardous Material 49 CFR Parts 107, Regulates transportation of Yes/--- Applicable to ofT-site disposal of wastes.
Transportation Regulations 171-177 hazardous materials.
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TABLE C-4
IDENTWICATION OF STATE ACTION.SPECIFIC ARARs
Applicable/
Relevant
Standard, Requirement, and
Criteria, or Limitation Citation De8o'iption Appropriate Comment
State Engineer, Department Title 73, Chapter 3, Well drilling standards for Yes/--- Includes such requirements as
of Natural Re8ouroes U.C.A., Rule R625-4, drilling and abandonment performance standards for casing joints,
U.A.C. of wells. requirements for abandoning wells, etc.
Industrial Commission Title 35, Chapter 9, Utah Occupational Safety Yes/m . These rules are identical to Federal OSHA
U.C.A., Utah Admin. and Health Standards regulations.
\1 Code R500
....
t-:I
Division of Solid and Title 19, Chapter 6, Solid Waste. Not yet Yes/--- These rules govern solid waste landfills.
Hazardou8 Waste, U.C.A. . codified; copy available from
Deportment rA the Bureau of Solid and
Environmental Quality Hazardous Waste.
Title 19, Chapter 5, Solid and Hazardous Waste. Yes/--- R450-9, regarding spil1 reporting
U.C.A., Utah Admin. requirements, has no corresponding
Code R450 Federal provisions.
Title 19, Chapter 5, Corrective Action Clean-up Yes/-u Lists general criteria to be considered in
U.C.A., Utah Admin. Standards Policy - RCRA, establishing clean-up standards.
Code R450~101 UST, and CERCLA sites.
Division of Water Quality, Title 19, Chapter 5, Sewers and wastewater No/Yes Construction and performance
Department.of U.C.A., UtaJt Admin. treatment works. requirements.
Environmental Quality Code R448-3
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TABLE C-4
IDENTIFICATION OF STATE ACTION-SPECIFIC ARARs
(CONTINUED)
Standard, Requirement,
Criteria, or Limitation
Citation
Applicable/
Relevant
and
Appropriate
Comment
(')
,
....
c,.)
Division of Air Quality,
Department of
Environmental Quality
Description
Title 19, Chapter 5, Underground injection
U.C.A., Utah Admin. control.
Code 448-7
Yes/---
See particularly R448-7-9 specifying
technical requirements.
There is no corresponding federal
program.
Requires application of best available
control technology for any source, lists
criteria to be considered in establishing
visibility standards, sets visible emission
standards, regulates fugitive dust
emissions, allows the State to require
temporary closure of air pollution sources
in the event of an air pollution emergency
episode, and includes a limit of 1.5 tons of
annual emissions of VOCs without
obtaining a pennit. Relevant and
appropriate to on-site air stripper
emissions.
Title 19, Chapter 5, Ground-Water Quality
U.C.A., Utah AdIriin. Protection.
Code 448-6
Yes/---
Title 19, Chapter 2,
U.C.A., Utah Admin.
Code R446-12
Utah Air Conservation Rules
No/Yes
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