N
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Unhed States
Environmental Protection
Agency
Off ice of
Emergency and
Remedial Response
SEP 191994
EPA/ROD/R06-93/082
September 1993
PB94-964202
SERA Superfund
Record of Decision:
Tenth Street Dump/
Junkyard (Amendment), OK
X
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AMENDED RECORD OF DECISION
TENTH STREET SITE
OKLAHOMA CITY, OKLAHOMA
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
SEPTEMBER 1993
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DECLARATION
TENTH STREET SITE
Statutory Preference for Treatment
as a Principal Element is Not Met
and Five-Year Review is Required
SITE NAME AND LOCATION
Tenth Street Site
3200 N.E. Tenth Street
Oklahoma City, Oklahoma
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for
the Tenth Street Site, in Oklahoma City, Oklahoma, which was
chosen in accordance with the Comprehensive Environmental
Response, Compensation, and Liability Act of 1980 (CERCLA), as
amended by the Superfund Amendments and Reauthorization Act of
1986 (SARA) (42 U.S.Code, Section 9601, et seq.), and, to the
extent practicable, the National Contingency Plan (NCP)(40 CFR
Part 300). This decision is based on the Administrative Record
for this site.
The State of Oklahoma concurs with the selected remedy.
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 Record of Decision, may present an imminent and
substantial endangerment to public health, welfare, or the
environment.
DESCRIPTION OF THE REMEDY
This Record of Decision (ROD) amends the original Record of
Decision executed by the Regional Administrator on September 27,
1990. This amended remedy addresses approximately 9,800 cubic
yards of soil at the site contaminated with polychlorinated
biphenyls (PCBs) at or above 25 ppm. Specifically, this amended
remedy addresses the threats to human health and the environment
at the site by eliminating the inhalation, ingestion, and direct
contact exposure pathways.
The major components of the selected remedy include:
Excavation and placement of contaminated soil from the
roadway right-of-way on the south side of N.E. Tenth Street
onto the existing cap;
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Allowing the Oklahoma Department of Transportation's
widening of Tenth Street to cover contaminated soil in the
roadway right-of-way on the North side of N.E. Tenth Street;
Construction of a new cap meeting the technical requirements
for caps under the Toxic Substances Control Act (TSCA), 40
CFR S761.75(b)(1) and (2) ;
Maintenance of the cap and ground water monitoring.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that
are legally applicable or relevant and appropriate to the
remedial action, and is cost-effective. This remedy utilizes
permanent solutions and alternative treatment technologies to the
maximum extent practicable. However, because contamination at
the site presents only low level threats, and treatment of the
contaminated soil at the site was not found to be practicable,
this remedy does not satisfy the statutory preference for
remedies that employ treatment as a principal element. The
questionable success of alternative technologies, the comparable
risks of off-site disposal, and the strong preference of the
State for onsite disposal preclude the selection of a remedy in
which the contaminants of concern would be treated.
Because this remedy will result in hazardous substances remaining
onsite above health-based levels, a review will be conducted
within five years after commencement of remedial action to ensure
that the remedy continues to provide adequate protection of
public health, welfare, and the environment.
A
D. Winkle Date
Acting Regional Administrator
Region 6
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TENTH STREET SUPBRFUND SITE
OKLAHOMA CITY, OKLAHOMA
AMENDED RECORD OF DECISION
TABLE OF CONTENTS
TITLE PAGE
I. INTRODUCTION 1
a. Site Name and Location 1
b. Background 6
c. State Agency Involvement 6
d. The Previous Record of Decision 6
II. SITE CONTAMINATION AND RISKS TO HUMAN HEALTH 6
III. RATIONALE FOR AMENDING THE RECORD OF DECISION 8
a. Circumstances Leading to this ROD Amendment 8
b. Experience With the KPEG Process at Other Sites....8
c. Rationale for Changing the Remedy 10
IV. HIGHLIGHTS OF COMMUNITY PARTICIPATION 11
V. REMEDIATION GOALS 11
a. Areas of Concern 11
b. Remedial Obj ectives 12
VI. DESCRIPTION OF ALTERNATIVES 12
a. Common Elements 13
b. Description of Alternatives 13
VII. EVALUATION OF ALTERNATIVES 16
a. Explanation of Evaluation Criteria 16
b. Comparative Analysis 18
VIII. SELECTED REMEDY 23
IX. STATUTORY DETERMINATIONS 26
X. DOCUMENTATION OF SIGNIFICANT CHANGES 30
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FIGURES
Figure 1 - Site Location
Figure 2 - Site Map
Figure 3 - Area of PCB Contamination Above 25 ppm.
Figure 4 - Conceptual Cap Cross-Section
, .2
, .3
, .5
,25
TABLES
Table 1 - Comparative Analysis of Alternatives.
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APPENDICES
APPENDIX I
APPENDIX II -
APPENDIX III -
RESPONSIVENESS SUMMARY
OKLAHOMA STATE AGENCY COMMENT LETTERS
ADMINISTRATIVE RECORD INDEX UPDATE
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DECISION SUMMARY
FOR THE
TENTH STREET SUPERFUND SITE
OKLAHOMA CITY, OKLAHOMA
I. INTRODUCTION
a. Site Name and Location
The Tenth Street Superfund Site (the "site") is located at
3200 Northeast Tenth Street, on the east side of Oklahoma
City, Oklahoma (Section 31, Township 12 North, Range 2 West,
of Oklahoma County) (Figure 1). The site is approximately
3.5 acres in size and is fenced. The site is situated
immediately south of N.E. Tenth Street, between the North
Canadian River on the east and south, and Bryant Avenue on
the west (Figure 2).
The site is in an area of mixed residential and industrial
land use, and is surrounded on three sides by active
automobile salvage yards. In the September 27, 1990, Record
of Decision (ROD), the Environmental Protection Agency (EPA)
assigned an industrial land use to this site. This
industrial land use is maintained in this ROD.
b. Background
Between 1951 and 1959, the site was operated as a municipal
solid waste landfill. From about 1959 until his death in
1979, Mr. Raymond Cobb leased the site and operated it as a
salvage yard. During this time, used electrical
transformers, as well as other materials such as used tires
and paint thinners, were accepted by the salvage yard.
Substantial quantities of dielectric fluid from the
transformers were spilled on the ground during salvage
operations. This dielectric fluid contained polychlorinated
biphenyls (PCBs). After Mr. Cobb's death, Mr. Rolling
Fullbright operated the site as an automobile salvage yard
called Deadeye's Salvage Yard.
As the result of investigations during 1983, 1984 and 1985,
EPA determined the site represented an unacceptable risk to
human health and the environment. In August 1985, the EPA
Region 6 Regional Administrator approved a removal action
for the site. The removal action consisted of: (1) removal
of electrical equipment and drums containing hazardous
substances (e.g., benzene, acetone, and tetrachloroethylene)
from the site; (2) decontamination and relocation of junk
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automobiles; (3) consolidation of PCB contaminated soils to
the center of the site and grading for drainage; (4)
installation of a temporary cap, consisting of a visqueen
layer overlain by approximately 18 inches of clay; and (5)
erection of a fence.
In July 1987, the site was placed on the National Priorities
List (NPL). In 1989, EPA conducted a remedial investigation
and feasibility study (RI/FS) for the site. The RI was
finalized in March 1990, and EPA determined no ground water
contamination was present at the site and that soil
contamination with concentrations of PCBs at or above 25
parts per million (ppm) was limited to approximately 7,500
cubic yards of soil under the cap at the site. The FS and
risk assessment were completed in July 1990. Based on
concentration and risk, PCBs were determined to be the
contaminants of concern.
The FS concluded, based on a treatability study, the KPEG
chemical dechlorination process was an innovative technology
which would be capable of destroying the PCB contamination.
Additional investigations conducted during the remedial
design (RD) have since increased the volume estimate to
identify approximately 9,800 cubic yards of soil
contaminated with PCBs at or above 25 ppm at the site. The
majority of the contaminated soil is contained under the
existing temporary cap constructed during EPA's removal
action in 1985. However, some contaminated soil is present
off-site in the roadway right-of-way on both the north and
south sides of N.E. Tenth Street (Figure 3).
In addition to indicating no ground water contamination is
present at the Tenth Street Site, the water table across the
area was measured during the RI. The water table was
approximately 8 feet below the original ground surface and
ranges from 1151.75 feet above mean sea level (+MSL) to
1150.52 feet +MSL. The highest water level measured within
the site boundary was 1150.82 feet +MSL; the deepest
contamination is reported to be at 1154.5 feet +MSL, a
difference of 3.68 feet.
Although insufficient information exists to classify the
alluvial aquifer at the site, EPA believes the appropriate
classification is Class II, potential drinking water supply.
The aquifer is not contaminated with PCBs, meets primary
drinking water standards, does not exceed 10,000 ppm total
dissolved solids, and probably yields more than 150 gallons
per day. No users of the alluvial aquifer have been
identified; all known water supply wells in the immediate
area are probably completed in the Garber-Wellington.
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c. State Agency Involvement
EPA is the lead agency for the Tenth Street Site. The
Oklahoma Department of Environmental Quality (ODEQ) and its
predecessor, the Oklahoma State Department of Health (OSDH),
have provided administrative and technical support on this
site, and have reviewed the Administrative Record and the
Proposed Plan for this Amended ROD.
d. The Previous Record of Decision
The original ROD was signed on September 27, 1990, by the
Regional Administrator for EPA Region 6. The ROD selected
the chemical dechlorination process (KPEG), an innovative
treatment technology, to treat the PCB contaminated soils
with concentrations at or above 25 ppm.
II. SITE CONTAMINATION AND RISKS TO HUMAN HEALTH
During the RI, EPA conducted sampling of the soil, ground water
and surface water to determine the nature and extent of
contamination. Additional sampling was conducted during the RD
phase for the original remedy. The results of these
investigations indicated that soil contamination presents
unacceptable long-term health risks. Based on concentration and
risk, PCBs are the contaminants of concern for this site. PCBs
are also hazardous substances as defined in Section 101(14) of
the Comprehensive Environmental Response, Compensation and
Liability Act (CERCLA), 42 U.S.C. §9601(14) and 40 CFR S302.4.
Aroclor 1260 is the predominant species present, but Aroclor 1242
and Aroclor 1254 are present in minor amounts. EPA estimates
9,800 cubic yards of soil are present at the site with PCB
contamination at or above 25 ppm.
In its usual form, PCBs are immobile. Investigations conducted
at this site revealed the PCB contamination appears to be
strongly bonded with the soil and is very immobile. PCB
concentrations in soil samples range from 41 ppm to 1,700 ppm.
The average concentration of PCBs in the soil is 110 ppm.
EPA has performed two human health risk assessments for this
site. A baseline risk assessment was conducted in July 1990, and
was discussed in the September 27, 1990, ROD. As part of the ROD
amendment process, a second risk assessment was prepared in March
1993. Both risk assessments examined potential threats to
workers exposed to the site in an industrial setting, reflecting
EPA's determination that the most likely potential future land
use of the site is industrial. Both risk assessments considered
the effects of direct exposure to the soil, without regard to the
mitigating effects of the present cap.
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Two exposure scenarios were examined in the 1993 risk assessment.
The Central Tendency Exposure (CTE) addresses a worker on an
industrial site for eight hours per day, five days a week, 50
weeks per year, with an average duration of exposure of nine
years. The Reasonable Maximum Exposure (RME) differs in that it
assumes a duration of exposure of 25 years. Pathways of exposure
examined included ingestion of soil and dermal absorption of soil
and dusts. Both exposure scenarios assumed a PCB concentration
of 1700 ppm in the soil, which was the highest concentration
detected during the RI.
The 1993 risk assessment indicated that for noncarcinogenic human
health effects from PCBs, the Hazard Index (HI) for the CTE
exposure was l, and for the RME exposure the HI was 7. An HI
greater than 1 indicates a potential for human health concern.
For carcinogenic effects from PCBs, the CTE exposure may result
in 9 excess cancer cases (above the normal average cancer
occurrences) in 10,000 individuals (a risk of 9 x 10"4). For the
RME exposure, 4 excess cancer cases may result in 1,000
individuals (a risk of 4 x 10'3). Action is generally warranted
at Superfund sites if, as at the Tenth Street Site, the
cumulative carcinogenic risk to an individual based on the RME
for both the current and future land use is less than 1 x 10"4
(OSWER Directive 9355.0-30).
Additionally, the RI indicated lead is present in the soil at
this site. The average lead concentration in soil at the site is
1,100 ppm. This level slightly exceeds the EPA recommended
cleanup range of 500 - 1,000 ppm for residential areas (OSWER
Directive #9355.4-02). As EPA does not have a recommended model
for an industrial exposure scenario, the 1993 risk assessment
evaluated this site using EPA's Uptake/Biokinetic (UBK) model.
The UBK model is used to predict blood lead levels in children
ages birth to 7 years old (which represents the sensitive
population) who are exposed in a residential setting. (This
model cannot be modified to simulate an industrial exposure.)
The UBK model predicted that 81% of children would develop a
blood lead level below the 10 micrograms per deciliter (/ig/dl)
benchmark. For exposures to children in a residential setting,
EPA recommends a model projection of 95% with blood lead levels
below 10 Mg/dl (Don Clay Memo, "Update on OSWER Soil Lead Cleanup
Guidance", August 29, 1991). Therefore, the model indicates the
site would pose an unacceptable lead exposure to children in a
residential setting. However, because (1) the most likely future
use of the site would be industrial rather than residential, and
(2) the automobile salvage industry surrounding the site is
generally associated with high lead levels and would continue to
be a source of exposure and possibly recontaminate the site, EPA
does not believe lead poses a significant risk at this site, and
lead is, therefore, not a contaminant of concern to be addressed
in this ROD.
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However, as a point of clarification, the potential health
threats from both PCBs and lead discussed above would only be
posed by direct exposure to contaminated soil at the site.
Currently, because of the protection offered by the temporary cap
and fencing, threats to human health and the environment from
direct exposure to the contaminated soil are minimal at the site.
The U.S. Fish and Wildlife Service granted a release from natural
resources damages for the site on August 27, 1987. However, if
not addressed by this remedy or some other measures, actual or
threatened releases of hazardous substances from this site may
occur, and may endanger public health, welfare, and the
environment.
III. RATIONALE FOR AMENDING THE RECORD OF DECISION
a. Circumstances Leading to this ROD Amendment
Following the signature of the ROD on September 27, 1990,
EPA began the RD phase of the KPEG chemical dechlorination
process to address the PCB contaminated soils. The ROD had
estimated costs for remediation of this site to be
approximately $4 million.
The State of Oklahoma did not support the remedy selected in
the September 27, 1990, ROD. The State believed that the
risks posed by the site were minimal and that public health
protection achieved through the use of physical and legal
land use restrictions would be comparable to the protection
achieved by the KPEG treatment process. The State also
believed that the cost associated with KPEG was not
warranted.
EPA proceeded with the design of the selected remedy in
November 1990. EPA believed that issues with the State of
Oklahoma could be resolved as the remedial design
progressed, with the goal of minimizing project delays.
On October 25, 1991, EPA received from the remedial design
contractor the 60% remedial design submittal, which included
the proposed schedule and cost estimate. The contractor
estimated the cost of the remediation to be $8.125 million.
On November 22, 1991, EPA issued a stop work order to the
remedial design contractor, suspending the remedial design.
EPA intended to re-evaluate the appropriateness of the
selected remedy.
b. Experience With the KPEG Process at Other Sites
As part of EPA's re-evaluation of the KPEG process, EPA
considered information from the Industrial Transformer/Sol
Lynn (IT) Superfund Site in Houston, Texas.
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EPA had selected the KPEG chemical dechlorination process as
an innovative technology treatment remedy for the IT site in
a ROD issued in March 1988. The IT site's treatment unit
became operational in November 1991. The Responsible Party
for the IT site. Gulf State Utilities (GSU), began treating
soil from the site with an average PCB concentration of 50
ppm in December 1991.
In February 1992, GSU contacted EPA and asked permission to
discontinue treatment due to numerous problems with the
treatment process. GSU claimed that due to the low
production rate of the unit, the increasing odor problem,
and the condition of the treated soil, continuation of the
KPEG innovative technology was not justified.
Following the request from GSU to cease treatment of the
soils, EPA undertook an evaluation to determine the validity
of GSU's concerns about the effectiveness and efficiency of
the KPEG chemical dechlorination process. EPA Region 6
requested the assistance of the EPA Office of Research and
Development, Risk Reduction Engineering Lab to assess the
following factors affecting the KPEG process:
1. The offensive odor that persists during treatment
of the soil, and the residual odor in the soil after
treatment.
2. Treating the soil increased the volume of the soil
by approximately 100%.
3. The leaching of residual reagent from the soil
following treatment.
4. The physical characteristics of the treated soil,
which required storage in 30 yard roll-off boxes
because of its physically "soupy11 nature, resulted in
the need for stabilization before using as backfill.
5. The rate of production of the treatment unit was
averaging one to two tons/day, although it was
estimated in the IT site's RD at 20 tons/day.
On February 25, 1992, a representative from the EPA Office
of Research and Development (ORD) visited the IT site to
evaluate the problems with the KPEG innovative technology
treatment process. The evaluation included meetings with
the vendor operating the chemical dechlorination equipment;
the managing consultant for the project; and representatives
of GSU. An onsite inspection of the equipment and review of
the treatability study and design documents was also
conducted. ORD summarized their evaluation in a memo to EPA
Region 6 dated February 27, 1992, stating that three
fundamental problems are associated with using the chemical
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dechlorination treatment process: poor materials handling
abilities, low production rates, and poor soil quality. ORD
concluded that it was not possible to set a reliable
schedule for completion of the remediation using the KPEG
chemical dechlorination process. EPA sent a follow-up
letter to the vendor, asking for their input into solving
problems involving the KPEG process. The vendor did not
offer viable solutions to solve these inherent problems.
EPA Region 6 concluded, based on the assessment by ORD, that
the KPEG chemical dechlorination process was no longer
feasible at the IT site. Following treatment of
approximately 140 tons of contaminated soil and upon
approval from EPA on March 6, 1992, the process was
demobilized.
c. Rationale for Changing the Remedy
This amendment is necessary because of (1) the
implementation difficulties with the an innovative
technology of the KPEG chemical dechlorination process
discussed above, and (2) the increased costs associated with
this innovative technology at this site.
Even though treatability tests were conducted as part of the
FS for both the IT and Tenth Street Sites, this does not
ensure that full scale production is always successful. EPA
feels because the contaminants, soil conditions, and
treatment processes are very similar, the problems at the IT
site described above would likely be encountered at the
Tenth Street Site. The innovative technology of the KPEG
chemical dechlorination process therefore appears
technically impracticable, and thus would prevent an
effective implementation of the KPEG process at the Tenth
Street Site.
Additionally, the increased cost estimate of $8.125 million
greatly exceeds the costs projected in the September 27,
199O, ROD. Based on actual costs incurred for the KPEG
process at other sites, remediation costs at the Tenth
Street Site would likely exceed $10 million. This
additional cost would not result in an increase in overall
protection to human health and the environment. Actually ,
the problems with the KPEG innovative technology treatment
process may increase the risks at the site.
Therefore, EPA has determined that because of the technical
difficulties and increased costs, the innovative technology
of the KPEG chemical dechlorination process is no longer
appropriate for the Tenth Street Site.
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IV. HIGHLIGHTS OF COMMUNITY PARTICIPATION
The Amended Proposed Plan for the Tenth Street Site was released
for public comment in July 1993, pursuant to 40 CFR
§300.435(C)(2)(ii) and $117 Of CERCLA, 42 U.S.C. §9617. This
document, as well as other site related documents, were made
available to the public as part of the Administrative Record,
which has been updated in accordance with 40 CFR §300.825(a)(2).
Information repositories for the Administrative Record were
located at the EPA Region 6 offices at 1445 Ross Avenue, Suite
1200, Dallas, Texas, and at the Ralph Ellison Library, 2000 N.E.
23rd Street, Oklahoma City, Oklahoma. These locations, as well
as the preferred remedial alternative, were identified in the
Amended Proposed Plan and announced in notices in The Daily
Oklahoman on July 12, 1993, and in The Black Chronicle on July
15, 1993. The public comment period for the proposed plan began
on July 15, 1993 and ended on August 14, 1993. EPA conducted a
public meeting on July 29, 1993, to discuss the preferred
remedial alternative and to accept verbal comments. Responses to
the written and verbal comments received during this period are
included in the Responsiveness Summary, which is included as part
of this Amended ROD. This Amended ROD will be added to the
Administrative Record for this site. An update to the
Administrative Record Index is included as an Appendix III of
this document.
V. REMEDIATION GOALS
a. Areas of Concern
EPA classifies low-level threat wastes as those source
materials that generally can be reliably contained and that
would present only a low risk in the event of a release.
Wastes that generally will be considered to constitute low-
level threat wastes include, but are not limited to:
1. Nonmobile contaminated source material of low
toxicitv - surface soils containing contaminants of
concern that generally are relatively immobile in air
or ground water (i.e., nonliguid, low volatility, low
leachability contaminants such as high molecular weight
compounds) in the specific environmental setting.
Contamination at the Tenth Street Site is limited to
immobile contaminants (PCBs) and only in soil.
Additionally, EPA's Guidance on Remedial Actions for
Superfund Sites with PCB Contamination (OSWER Directive No.
9355.4-01, August 1990) identifies principal and low-level
threats for Superfund sites with PCB contamination. For
sites in industrial areas such as the Tenth Street Site,
principal threats are generally defined as concentrations of
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500 ppm or greater. Due to the consolidation and mixing of
contaminated soils during the removal action, it is not
practicable to separate soils from the Tenth Street Site
into those with PCB concentrations above and below 500 ppm.
However, the average concentration of PCBs in soils at the
Tenth Street Site is 110 ppm PCBs, which is considered a
low-level threat.
Based on the above criteria, the contamination at this site
presents only low-level threats.
However, as stated in Section II, "Site Contamination and
Risks to Human Health", risk assessments conducted for the
site show the site poses unacceptable risks to human health,
and remedial action is necessary to ensure continued
protection from exposure to contaminated soils.
b. Remedial Objectives
The objective of remediation at this site, as stated in the
September 27, 1990, ROD, is to protect human health and the
environment "...by preventing current or future exposure to
the contaminated soil through treatment and/or containment,
and reducing or controlling the potential migration of
contaminants from the soil to ground water." This continues
to be the objective of remediation at this site.
The target action level for this remedial action addresses
PCB contamination in soil at or above 25 ppm. This standard
assumes the industrial land use specified in the September
27, 1990, ROD, and is based on the Toxic Substances Control
Act (TSCA) PCB Spill Cleanup Policy (40 CFR S?61 Subpart G).
EPA estimates 9,800 cubic yards of soil with PCB
contamination at or above 25 ppm are present at the Tenth
Street Site and subject to this remedial action.
No ground water contamination has been identified at the
Tenth Street Site.
VI. DESCRIPTION OF ALTERNATIVES
Six remedial alternatives were developed for the Tenth Street
Site in the 1990 FS. An Addendum to the FS was prepared in April
1993 which updates these six alternatives. These documents can
be found in the Administrative Record for the Tenth street Site.
The remedial alternatives are:
Alternative 1: No Action
Alternative 2: Capping in Place
Alternative 3: Excavation and Off-site Disposal
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Alternative 4: Excavation, Onsite Chemical Dechlorination (KPEG)
and Disposal
Alternative 5: Excavation, Onsite Thermal Treatment and Disposal
Alternative 6: Excavation, Off-site Thermal Treatment and
Disposal
The original remedy selected for the site in the September 27,
1990, ROD, was Alternative 4: Excavation and Onsite Chemical
Dechlorination (KPEG) and Disposal. EPA has determined this
remedy is no longer appropriate for this site; however, for
comparison purposes only, the Alternative 4 is described below.
a. Common Elements
All alternatives address the approximately 9,800 cubic yards
of soil with concentrations of PCBs at or above 25 ppm.
Alternatives 1 and 2 would leave the contaminated soil in
place on the site. Monitoring would be conducted to ensure
no migration of PCBs to the ground water. Alternatives 3,
5, and 6 would excavate the contaminated soil for either
treatment or off-site disposal. All alternatives except
Alternative 1 would be subject to the requirements of the
Occupations Safety and Health Act (OSHA) of 1970 {29 U.S.C.
651 et seq.I. the EPA regulations set forth in 40 CFR Part
300, and the Oklahoma Clean Air Act. An air monitoring
program and dust control measures would be implemented to
reduce/minimize any potential adverse short-term health
effects during excavation and treatment activities.
b. Description of Alternatives
Alternative is No Action
Estimated Capital Costs: $2,500
Estimated Annual (O&M) Costs: $14,900
Estimated Total Present Worth Costs: $229, 500
Estimated Implementation Timeframe: 30 years for Operation
and Maintenance (O&M)
The Superfund program requires that the "No Action"
alternative be evaluated at every site to establish a
baseline for comparison. Under this alternative, deed
notices would discourage soil excavation and construction
activities on the site. The ground water monitoring wells
located downgradient from the site would be sampled and
analyzed for PCBs at least annually to ensure no migration
of PCBs to ground water has occurred. The TSCA PCB disposal
requirements (40 CFR 761 Subpart D) and the PCB Spill
Cleanup Policy would not apply to this alternative because
the soils would be left in place and no waste would be
generated.
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Alternative 2: Capping in Place
Estimated Capital Cost: $407,800
Estimated Annual (O&M) Costs: $15,600
Estimated Total Present Worth Costs: $648,000
Estimated Implementation Timeframe: 3 months construction;
30 years for O&M
Under this alternative, the waste would remain in place. A
new, multimedia cap meeting the requirements for chemical
waste landfill covers (found at 40 CFR 5761.75 (b)(1) and
(2)) would be constructed over the existing cap. Off-site
contamination in the roadway right-of-way on the south side
of N.E. Tenth Street would be excavated and placed onto the
existing cap. All soil contaminated with PCBs above 25 ppm
would be capped under either the new cap or, in the case of
off-site contamination in the roadway right-of-way on the
north side of N.E. Tenth Street, the new, widened pavement,
which would serve as a cap. EPA and the Oklahoma Department
of Transportation have agreed clean fill soil would be
placed over the existing soil prior to construction of the
new road to ensure no disturbance of PCB contaminated soil
during construction. The downgradient ground water
monitoring wells would be sampled and analyzed for PCBs
annually to ensure no migration of PCBs to ground water.
The site will be fenced and deed notices filed to restrict
access to the site. TSCA's PCB disposal requirements and
PCB Spill Cleanup Policy would not apply to this alternative
because the soils would be left in place and no waste would
be generated. However, this alternative does comply with
the 25 ppm cleanup level established in the TSCA Spill
Cleanup Policy.
Alternative 3: Excavation and Off-Sit* Disposal
Estimated Capital Cost: $5,507,600
Estimated Annual (O&M) Costs: $0
Estimated Total Present Worth Costs: $5,507,600
Estimated Implementation Timeframe: 3 months
Under this alternative, the estimated 9,800 cubic yards of
contaminated soil would be excavated and disposed of in an
off-site commercial landfill approved under TSCA to accept
PCB contaminated soils. The excavated area would be
backfilled with clean soil. The final surface would be
graded and seeded to blend with the surrounding area. No
after action monitoring and/or maintenance would be
required. This alternative would meet TSCA's PCB disposal
requirements and the PCB Spill Cleanup Policy.
14
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Alternative 4: Excavation, Onsite Chemical Dechlorination,
and Onsite Disposal
Estimated Capital Cost: $8,125,000
Estimated Annual (O&M) Costs: $0
Estimated Total Present Worth Costs: $8,125,000
Estimated Implementation Timeframe: 18-20 months
Under this alternative, the estimated 9,800 cubic yards of
contaminated soil would be excavated and treated. This
remedy was described in the September 27, 1990, ROD as
follows:
"Contaminated soil is mixed with an alkaline reagent
consisting of potassium or sodium hydroxide in a
solution of mixed polyethylene glycol and dimethyl
sulfoxide. The reagent mixture dechlorinates the aryl
halide to form a PEG ether and a totally dechlorinated
species.
"In soil processing, the soil/reagent mixture is heated
to 30° - 150° C with mixing until the reaction has been
completed. At the end of the reaction, reagent is
recovered by decantation and washing the soil with
several volumes of water. The decontaminated soil is
then discharged" and placed backed on the site.
EPA no longer considers the KPEG innovative treatment
technology to be appropriate for this site due to the
reasons discussed in Section III, "Rationale for Amending
the Record of Decision".
Alternative 5: Excavation, Onsite Thermal Treatment and
Disposal
Estimated Capital Cost: $11,068,600
Estimated Annual (O&M) Costs: $0
Estimated Total Present Worth Costs: $11,068,600
Estimated Implementation Timeframe: 6-9 months
Under this alternative, the estimated 9,800 cubic yards of
contaminated soil would be excavated and treated in a mobile
incinerator which would be brought to the site. The thermal
destruction unit would comply with the technical standards
for PCS incinerators found at 40 CFR $761.70. Emissions
resulting from the incineration would be scrubbed before
venting to the atmosphere. Scrubber water would be
incinerated or treated by filtration through activated
carbon columns. The spent carbon would then be incinerated.
The incinerator would operate with a demonstrated removal
efficiency (DRE) of 99.9999 percent for PCBs. After
incineration, the ash would be graded and seeded to blend
with the surrounding area. If necessary, supplemental clean
15
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soil would be added to site. No after action monitoring
and/or maintenance would be required. The alternative would
meet TSCA PCB incineration requirements, the TSCA PCB Spill
Cleanup Policy, and the Oklahoma Clean Air Act.
Altarnative 6: Excavation, Off-sit* Thermal Treatment and
Disposal
Estimated Capital Cost: $34,207,100
Estimated Annual (O&M) Costs: $0
Estimated Total Present Worth Costs: $34,207,100
Estimated Implementation Timeframe: 3 months
Under this alternative, the estimated 9,800 cubic yards of
contaminated soil would be excavated and transported to an
off-site, TSCA permitted, commercial incinerator. The
excavated area would be backfilled with clean fill soil and
graded and seeded to blend with the surrounding area. No
after action monitoring and/or maintenance would be
required. The alternative would meet TSCA requirements for
PCB disposal and incineration, and the TSCA PCB Spill
Cleanup Policy.
VII. EVALUATION OF ALTERNATIVES
EPA uses the nine criteria set forth in 40 CFR
§300.430(e)(9)(iii) to evaluate alternatives for addressing a
Superfund site. These nine criteria are categorized into three
groups; threshold, primary balancing, and modifying. The
threshold criteria must be met in order for an alternative to be
eligible for selection. The primary balancing criteria are used
to weigh major tradeoffs among alternatives. The modifying
criteria are taken into account after state and public comment is
received on the Proposed Plan of Action.
a. Explanation of Evaluation Criteria
The nine criteria used in evaluating all of the alternatives
are as follows:
Threshold criteria
• Overall Protection of Human Health and Environment
addresses whether or not a remedy provides adequate
protection and describes how risks posed through each
pathway are eliminated, reduced, or controlled through
treatment, engineering controls or institutional
controls. Total elimination of risk is often
impossible to achieve. However, a remedy must
eliminate, reduce or control exposures to assure that
human health and the environment are protected.
16
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• Compliance with ARARs addresses whether or not a remedy
will meet all of the applicable or relevant and
appropriate requirements of other Federal and State
environmental statutes and/or provide grounds for
invoking a waiver.
Primary Balancing Criteria
• Long-term effectiveness and permanence refers to the
magnitude of residual risk and the ability of a remedy
to maintain reliable protection of human health and the
environment over time once remediation goals have been
met.
• Reduction of toxicity, mobility, or volume through
treatment is the anticipated performance of the
treatment technologies that may be employed in a
remedy. Factors considered include the nature of the
treatment process and the materials they will treat;
the amount of hazardous materials that will be
destroyed by the treatment process; how effectively the
process reduces or destroys the toxicity, mobility or
volume of contaminated material; the degree to which
the treatment is irreversible; the type and quantity of
contamination that will remain after treatment; and the
degree to which treatment reduces the inherent hazards
posed by principle threats at the site.
• Short-term effectiveness refers to the speed with which
the remedy achieves protection, as well as the remedy's
potential to create adverse impact on human health and
the environment that may result during the
implementation period.
• Implementability is the technical and administrative
feasibility of a remedy, including the availability of
materials and services needed to implement the chosen
solution.
• Cost includes capital and operation and maintenance
(O&M) costs. Costs are compared to the overall
effectiveness that will result from implementing the
alternative.
Modifying Criteria
• State Acceptance indicates whether, based on its review
of the Amended Proposed Plan, the State concurs with,
opposes, or has no comment on the preferred
alternative, or whether the State comments on ARARs or
the proposed use of waivers.
17
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• Community Acceptance allows for a public comment period
for interested persons or organizations to comment on
the proposed remedy. EPA considers these comments in
making its final remedy selection. The comments are
addressed in the Responsiveness Summary which is
attached to this Amended ROD.
b. Comparative Analysis
The original remedy selected for the site in the September
27, 1990, ROD, was Alternative 4: Excavation and Onsite
Chemical Dechlorination (KPEG) and Disposal. EPA has
determined this remedy, which utilized an innovative
treatment technology, is no longer appropriate for this
site; however, for comparison purposes only, the KPEG
alternative is retained for analysis. A brief synopsis of
this analysis is contain in Table 1.
Overall Protection of Human Health and the Environment
Under Alternative 1, No Action, the site does not protect
human health and the environment due to off-site PCB
contamination above 25 ppm in the roadway right-of-way.
Additionally, because of the temporary nature of the
original cap construction, and the lack of cap maintenance,
Alternative l may not provide adequate protection of human
health and the environment in the future from risks
associated with the PCB contaminated soil under the cap, and
will not be considered further in this analysis as an option
for this site.
Under Alternative 2, Capping in Place, a new cap would be
constructed of low permeability clay and a flexible membrane
liner (FML), with a drainage layer and vegetative cover. The
new cap would be constructed over the existing cap.
Integrity would be much more reliable as a result of more
stringent construction standards and continued maintenance.
Also, site access would be restricted and deed notices would
discourage excavation or construction activities at the
site. Although no migration of PCBs to ground water is
predicted, contamination will remain at the site and the
potential for contaminant migration to the ground water will
exist. Therefore, ground water monitoring will be conducted
to verify no PCB migration is occurring. Alternative 2
provides adequate protection of human health and the
environment.
Alternatives 3, 4, 5 and 6 would provide a higher degree of
protection of human health and the environment at the site
than Alternative 1. Alternatives 3, 4, 5 and 6 achieve
protection by eliminating, reducing, or controlling risk
through removal and/or treatment of the PCB contaminated
soil. However, these alternatives do not provide a greater
18
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degree of protection than Alternative 2, so long as the
integrity of the cap is maintained.
All five (excluding Alternative l, No Action) remaining
alternatives would adequately reduce excess cancer risk from
exposure to soils with PCB contamination at or above 25 ppm,
and prevent migration of contamination from the site,
thereby providing overall protection of human health and the
environment.
Compliance with ARARs
Of the remaining five alternatives, all would comply with
their respective ARARs. Alternative 2, because it would
leave the waste in place, would not generate a waste subject
to the PCB disposal regulations of TSCA, which require
incineration, treatment or placement in a chemical waste
landfill; these are, however, requirements to be considered.
The TSCA PCB Spill Cleanup Policy is also a requirement to
be considered. This policy's 25 ppm cleanup level will be
complied with.
Because the contaminated soil is not left in place, the TSCA
PCB disposal regulations and the TSCA PCB Spill Cleanup
Policy do apply to Alternatives 3, 4, 5 and 6. These
alternatives would comply with these requirements.
PCBs are not regulated by the Resource Conservation and
Recovery Act (RCRA) as a hazardous waste and RCRA is not
applicable to this remedy.
All alternatives, except Alternative 1, would be subject to
the requirements of the Occupational Safety and Health Act
(OSHA) of 1970 {29 U.S.C. 651 et sea.I. the EPA regulations
set forth in 40 CFR Part 300, and the Oklahoma Clean Air
Act.
No other ARARs have been identified for this site.
Long Term Effectiveness and Permanence
Alternatives 4, 5 and 6 provide the highest degree of long-
term effectiveness and permanence as they use irreversible
treatment technologies to eliminate hazards posed by
contamination at this site.
Alternative 3 would provide a level of effectiveness and
permanence to the site equivalent to Alternatives 4, 5, and
6. However, the PCBs would not be destroyed, but rather
relocated to a TSCA regulated chemical waste landfill.
Therefore, long-term management of the waste will be
required similar to that of Alternative 2.
20
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Although Alternative 2 does not remove contamination from
the site and would require periodic maintenance and
monitoring, it can be fully effective as long as cap
integrity is maintained. Long-term maintenance of the cap,
which is provided for in this alternative, would effectively
control residual risk at the site. Cap technology has been
proven to have good reliability. Monitoring will be
conducted to ensure the cap remains effective at preventing
migration of PCBs to ground water and exposure to
contaminated soils.
Reduction in Toxicity, Mobility or Volume Through Treatment
Because no treatment is involved, Alternatives 2 and 3 would
not reduce the toxicity, mobility or volume of the
contaminants. Alternative 4 can destroy PCBs below 2 ppm
through chemical dechlorination. Alternatives 5 and 6 would
destroy 99.9999% of the PCB contamination in the soil
through an incineration treatment process.
Snort-term Effectiveness
Alternative 2 presents the least amount of risk to workers,
the community and the environment during the implementation
stage. Only contaminated soil in the roadway right-of-way
on the south side of N.E. Tenth Street would be excavated
and, therefore, the lowest level of potentially PCB
contaminated particulate emissions would be created.
Construction would be completed in 3 months.
Alternatives 4 and 5 would create particulate emissions from
the excavation, stockpiling, and handling of contaminated
soil. Emission control systems would be required on the
treatment processes to reduce or eliminate the release of
hazardous substances from the site. Alternative 4 would
require 18-20 months to implement, while Alternative 5 could
be complete in 6-9 months.
Alternatives 3 and 6 would have similar levels of short-term
effectiveness, with particulate emissions resulting from the
excavation and loading of contaminated soils. Additionally,
potential releases of contaminants could occur along the
route of transportation to an off-site facility. Each of
these alternatives could be completed in 3 months.
As fugitive dust emissions would be generated by each of
these alternatives, air monitoring and particulate controls
would be required to mitigate potential impacts on workers
the community and the environment.
All alternatives require site workers to have received OSHA
health and training for hazardous waste operations and to
comply with requirements for protective equipment.
21
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Implementability
Experience at other sites indicates Alternative 2 would be
relatively simple to implement and construct. The
engineering of protective caps is well established. Labor
and materials are readily available through many sources.
No special permits are required. Additional land will have
to be acquired in order to install the new cap over the
existing cap.
Alternatives 3 and 6 would be the simplest to implement as
no treatment or construction would be required onsite. No
special techniques, materials, permits or labor would be
required for implementation. Commercial facilities are
readily available.
Based on experience at other sites, Alternative 4 would be
very difficult to implement. Vendor availability is
limited. Treatment rates are low. Treated soil is of very
poor quality. Odors associated with the treatment process
and treated soil are objectionable and no odor controls have
been developed. Residual process reagent leaches from the
treated soil. Because of the poor physical integrity of the
treated soil, additional stabilization is required prior to
replacement of the soil into the excavated area. Because of
the doubling of soil volume in treatment/stabilization, some
soil may require off-site disposal.
Alternative 5 is the most complex alternative to implement.
Despite anticipated frequent downtime due to mechanical
complexity, incineration could reliably meet the required
treatment levels. It would require specially trained
operators. During operation, constant monitoring of the
emissions and periodic monitoring of the residues would be
required.
Cost
The total present worth for Alternative 2 is $648,000.
Capital costs for construction are $408,000. Annual
operations and maintenance costs are $15,600, with and
estimated present worth of $240,000.
Estimated capital costs are $5,508,000 for Alternative 3;
$8,125,000 for Alternative 4; $11,069,000 for Alternative 5;
and $34,207,000 for Alternative 6. No further operation and
maintenance is required for these alternatives.
These costs are detailed in the FS Addendum, which is
included in the Administrative Record.
22
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State Acceptance
After review of the Proposed Plan and the Administrative
Record, the State of Oklahoma has indicated that the risks
posed by this site do not warrant implementation of any of
the presented alternatives except Alternative 2.
The State of Oklahoma had previously stated the low degree
of risk posed by the site and the lack of a treatment
process with a proven operating experience (other than
incineration) make additional cleanup of this site
unnecessary. 40 CFR §300.510 (a) and (b)(1) prevent EPA
from implementing a fund-financed remedy unless the State
provides assurance to share 10 % of the cost of remedial
action. The State has indicated that because of the limited
availability of matching funds and the low risks, and
consequently low priority, of this site, the State did
notbelieve the original remedy was appropriate to this site
and would not provide the 10 % State match. EPA believes
the same circumstances would prevent the State from
providing the 10 % match for any other treatment remedies.
Therefore, EPA believes only Alternative 2 is acceptable to
the State of Oklahoma in this circumstance.
The State of Oklahoma through the Oklahoma Department of
Environmental Quality (ODEQ) has been provided the
opportunity to review and comment on this Amended ROD. The
State concurs with the selected remedy of capping in place.
Community Acceptance
At the Public Meeting held on July 29, 1993, some members of
the community expressed a preference for off-site disposal.
The location of the flood plain and the appropriateness of a
containment remedy in the floodplain was questioned. One
commentor suggested long-term storage until a new treatment
process capable of destroying PCBs without incineration is
developed. Several professional environmental consultants
felt treatment processes offered by their respective firms
may be appropriate for the site. All comments are addressed
in the Responsiveness Summary attached to this ROD.
VIII. SELECTED REMEDY
Based on consideration of the requirements of CERCLA, the
detailed analysis of the alternatives using the nine criteria,
and public comments, both the EPA and ODEQ have determined that
Alternative 2, Capping in Place, is the most appropriate
alternative for remediating the soil contamination at the Tenth
Street Site. The major components of this remedy include:
23
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• Elimination of exposure pathways by construction of a multi-
media cap over the existing cap, capping in place of
approximately 9,800 cubic yards of soils with PCB
concentrations equal to or greater than 25 ppm (Figure 4).
• The multi-media cap shall comply with the requirements for
soil and liners of chemical waste landfills specified at 40
CFR §761.75 (b)(1) and (2).
• Contaminated soil on the south side of N.E. Tenth Street
will be excavated and returned to the site prior to
construction of the new cap.
• Contaminated soils on the north side of N.E. Tenth Street
will be capped in place by the Oklahoma Department of
Transportation's widening of the Tenth Street pavement.
Clean soil will be placed over the contaminated soil prior
to commencement of operations in order to prevent exposure.
Oklahoma County has agreed to accept responsibility for
costs associated with removal of the new pavement should
remediation be determined necessary in the future.
• Erection of a fence to prevent public access.
• Prior to any soil handling activities an air monitoring plan
will be activated to ensure no health based exposure levels
are exceeded.
• Annual ground water monitoring of the downgradient
monitoring wells will be conducted to ensure no migration of
contamination. Should ground water contamination by PCBs be
confirmed, EPA shall evaluate the need to conduct additional
investigations. A second operable unit for ground water
may, or may not, be declared.
• Routine inspection and maintenance of the cap will be
conducted at least annually.
• Because this remedy leaves waste in place. Five Year Reviews
of the site are required to determine if the remedy remains
protective of human health and the environment.
• EPA and ODEQ have determined, based on information provided
by the Corps of Engineers, the Oklahoma City Chief Engineer,
and the Oklahoma Climatological Survey, that the site is
adequately protected from a 100-year flood and no additional
engineering controls are required.
This remedy meets the remedial objectives for the site, as
expressed in Section V. b., "Remedial Objectives", by controlling
exposure to PCBs in soil at concentrations above 25 ppm, and
preventing migration of PCBs to ground water, through containment
by capping in place.
24
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EPA believes that by eliminating exposure to soils contaminated
with PCBs above 25 ppm at the site, the increased risk posed by
those soils will be controlled to a level consistent with an
industrial land use. The 25 ppm PCB remediation goal for sites
with limited access, such as the Tenth Street Site, is a health
based criterion established under the Toxic Substances Control
Act (TSCA) and is contained in 40 CFR §761.125, "Requirements for
PCB Spill Cleanup".
EPA believes the selected alternative provides the best balance
among alternatives with respect to the criteria used to evaluate
remedies. Based on the information currently available, EPA
believes the selected alternative will (1) provide protection of
human health and the environment; (2) comply with ARARs; (3)
provide good short and long-term effectiveness; (4) be
implementable; (5) be cost effective; and (6) is acceptable to
both the State and community. Although this remedy will not meet
the statutory preference for remedies which employ treatment of
principle threats, it is consistent with EPA regulations, policy
and guidance on containment of low-level threat material.
IX. STATUTORY DETERMINATIONS
EPA's primary responsibility at Superfund sites is to undertake
remedial actions that achieve adequate protection of human health
and the environment. In addition, Section 121 of CERCLA
establishes several other statutory requirements and preferences
that the selected remedy must meet. Section 121 of CERCLA
specifies that when complete, the selected remedial action for
this site must comply with ARARs established under Federal and
State environmental laws unless a statutory waiver is justified.
The selected remedy also must be cost effective and utilize
permanent solutions and alternative treatment technologies or
resource recovery technologies to the maximum extent practicable.
Finally, the statute includes a preference for remedies that
employ treatment that permanently and significantly reduce the
volume, toxicity, or mobility of hazardous wastes as their
principal element. The following sections discuss how the
selected remedy meets these statutory requirements at the Tenth
Street Site.
Protection of Hmnan Health and the EnviroTi''T»f*'*
The selected remedy protects human health and the environment by
capping soils contaminated with PCBs above 25 ppm. Containment
of the contaminated soil beneath a multi-media cap controls risks
due to direct contact, inhalation or ingestion of PCBs, and
prevents migration of PCBs to the ground water.
The capping of the soils with concentrations of PCBs above 25 ppm
meets the remedial objectives established in the 1990 ROD and
stated in Section V.b. of this ROD. The remediation goal for
26
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this site of 25 ppm PCBs in soil is based on a health-based
criterion in the TSCA Spill Cleanup Policy. EPA determined in
the September 27, 1990, ROD that the most likely future land use
of the site is industrial; this land use is maintained in this
ROD.
EPA's investigations have determined that PCBs at the Tenth
Street Site are not likely to migrate to the ground water.
Further, installation of the multi-media cap should prevent the
formation of significant quantities of leachate. Because of the
specific site conditions, any leachate which is generated is not
likely to contain PCBs.
Although no ground water contamination has been detected, annual
monitoring of the downgradient monitoring wells well be conducted
to ensure no migration of PCBs to ground water is occurring.
Should contamination be detected, additional evaluations shall be
conducted in the future.
Compliance with Applicable or Relevant and Appropriate
Requirements;
The selected remedy will comply with all applicable relevant and
appropriate action-, chemical-, and location-specific
requirements (ARARs). The ARARs are presented as follows:
Action-specific Remediation ARARs:
The EPA regulations addressing the Superfund program as set
forth in 40 CFR Part 300 are applicable.
Dust Suppression - The State of Oklahoma has set applicable
standards for net ground level concentrations of particulate
emissions. The levels are established in the Oklahoma Clean
Air Act, Subchapter 29. The activities at the site will be
monitored for this standard. If the standards are exceeded,
then dust suppression activities will be implemented.
Chemical-specific Remediation ARARs:
The remediation goal is based on a health-based criterion in
the TSCA Spill Cleanup Policy. The criterion of 25 ppm PCBs
was selected as the remediation goal for the site. Because
this is a policy and not a requirement, the Spill Policy is
not an ARAR for this site; however, this policy was used to
establish the health-based remediation goal in the 1990 ROD
for the site, which establishes it as a remediation
requirement.
The requirements for chemical waste (PCB) landfills
specified at 40 CFR §761.75(b)(1) and (2) are not ARARs for
the cap to be constructed over the site, but will be
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complied with.
Location-specific Remediation ARARs:
Construction in a 100-year flood plain requires additional
engineering controls for protection from a 100-year flood
event (40 CFR §761,75(b)(4)). Prior to 1950, the Tenth
Street Site was in the North Canadian River channel. The
Corps of Engineers channelized the North Canadian River for
flood control, expanding and relocating the channel to its
current location. Although the Federal Emergency Management
Agency (FEMA) Flood Rate Insurance Map shows the site in the
100-year flood plain, the Corps of Engineers and the City
Engineer of Oklahoma City have stated the project design
flood for the river channelization project had a 100-year
frequency, which was to remain contained in the channel.
EPA accepts these assertions in determining the site is
adequately protected from a 100-year flood. Additionally,
the FEMA map shows the 100-year flood elevation at the site
is 1163 feet +MSL. The currently existing temporary cap
exceeds this elevation; construction of an additional cap
thickness will further elevate the cap above the flood
elevation. EPA has determined no additional engineering
controls for flood protection are required.
Cost-Effectiveness;
The selected remedy is cost-effective because it has been
determined to provide overall effectiveness proportional to its
cost of $648,000. The selected remedy effectively reduces the
hazards posed by contaminants at the site at a cost which is an
order of magnitude below the other alternatives' costs.
Utilization of Permanent Solutions and Alternative Treatment
Technologies (or Resource Recovery Technologies) to the Maxim11"
Extent Practical:
EPA has determined that the selected remedy represents the
maximum extent to which permanent solution and treatment
technologies can be utilized in a cost-effective manner for the
Tenth Street Site. EPA has determined that the selected remedy
provides the best balance in terms of long-term effectiveness and
permanence; reduction through treatment of toxicity, mobility, or
volume; short-term effectiveness; implementability; costs; the
statutory preference for treatment of principal threats; and
considering State and community acceptance.
The selected remedy does not include treatment as a principal
element. Treatment was found to be impracticable based on the
low level threats posed by the PCB contaminated soil; the
implementation problems of the previously selected innovative
technology; the strong preference by the State for the selected
alternative; and an order of magnitude increase in cost over
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those projected in the September 27, 1990, ROD, with no increase
in the overall protection offered by the remedy.
The capping in place alternative does provide long-term
effectiveness by eliminating any exposure pathways associated
with the soil by permanently containing the contaminated soil
beneath the cap. The alternative does not achieve a reduction of
toxicity, mobility, or volume through treatment because the
alternative does not involve treatment. The remedy will be
implemented quickly, minimizing short-term effects. Only a
minimal amount of excavation will occur.
Alternative treatment technologies have been attempted at the
site through the selection of the chemical dechlorination process
selected in the 1990 ROD. This technology was determined to no
longer be appropriate for the Tenth Street Site due to poor
performance at other Superfund sites.
Preference for Treatment as a Principal Element*
EPA's selected soil remedy does not employ treatment as a
principal element. The alternatives investigated for this site
included those which employ treatments which would satisfy
CERCLA's preference for remedies that employ treatment that
permanently and significantly reduces the volume, toxicity or
mobility of the hazardous substances, pollutants, and
contaminants over remedies that do not employ such treatment.
However, the treatment technology that is available is an order
of magnitude higher in cost and does not afford a greater overall
benefit.
EPA's Guidance on Remedial Actions for Superfund Sites with PCB
Contamination (OSWER Directive No. 9355.4-01, August 1990)
identifies principal and low threat areas for Superfund sites
with PCB contamination. For sites in industrial areas such as
the Tenth Street Site, principal threats are generally defined as
concentrations of 500 ppm or greater. As mentioned earlier, the
average concentration of PCBs in the soil at the site was 110
ppm, which is considered a low-level threat. The guidance
suggests that principal threats be addressed through treatment
while low-level threats may be suitable for containment remedies.
Exceptions to this suggestion are cost of treatment versus cost
of containment, the site is located in a sensitive area such as a
wetland, or containment is not feasible because the site is
located in a flood plain. None of the exceptions apply to the
Tenth Street Site.
Based on the above reasons, additional treatment does not appear
to be appropriate or beneficial.
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X. DOCUMENTATION OF SIGNIFICANT CHANGES
The Amended Proposed Plan for the Tenth Street Site was released
for public comment in July 1993. The Amended Proposed Plan
identified Alternative 2, Capping in Place, as the preferred
alternative. EPA conducted a public meeting on July 29, 1993, to
discuss the preferred alternative and obtain verbal comment from
the public and other interested parties. EPA reviewed all
written and verbal comments submitted during the public comment
period. Upon review of theses comments, EPA determined that no
significant changes to the proposed remedy, as identified in the
Amended Proposed Plan, were necessary.
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APPENDIX I
RESPONSIVENESS SUMMARY
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STATE OF OKLAHOMA
DEPARTMENT OF
TRANSPORTATION
200 N. E. 21st Street
Oklahoma City, OK 73105-3204
July 19, 1993
Ms. Melanie Ontiveros, P.E.
Community Relations Coordinator
U.S. EPA (Region 6)
1445 Ross Avenue (6H-MC)
Dallas, Texas 75202-2733
Dear Ms. Ontiveros:
Re: Proposed Plan to address soil contamination at the Tenth Street
Superfund site in Oklahoma City.
The Oklahoma Department of Transportation (ODOT) supports the
Environmental Protection Agency's preferred alternative of Capping
In Place soils that have been contaminated by polychlorinated
biphenyls (PCBs) at the Tenth Street Superfund site in Oklahoma
City. ODOT feels that because PCBs are not highly mobile this
remedial action will be an adequate solution.
Sincerely,
R."J. Driskill, P.E.
Planning Engineer
RJD/Jck
cc: Scott Thompson, Solid Waste Managemet Service, ODEQ
AN EQUAL OPPORTUNITY EMPLOYER
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MARK S. COLEMAN W*^W DAVID WALTERS
Executive Director xgjsijISy Governor
State of Oklahoma
DEPARTMENT OF ENVIRONMENTAL QUALITY
August 9,1993
Mr. Donald H. Williams, Chief
Oklahoma/Texas Remedial Section
U.S. Environmental Protection Agency
1445 Ross Avenue, Suite 1200
Dallas, Texas 75202-2733
Dear Mr. Williams:
Attached is an explanation of the position of the Oklahoma Department of Environmental
Quality (DEQ) on the proposed plan for the Tenth Street Superfund site. This can be
considered as our comments on the preferred alternative. If you have any questions do not
hesitate to call me at (405)271-7169.
Sincerely,
Dennis J. Hrebec, Ph.D.
Director, Superfund Program
Solid Waste Management
Attachment
. o
1 c.---
1000 NortlMMl T«iih Stmt, Oklahou City. OkUhom. 73117-1212
<& ncyctedMi
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The purpose of this document is to explain the position of the Oklahoma Department of
Environmental Quality (DEQ) regarding the proposal by the United States Environmental
Protection Agency (EPA) to construct a permanent cap on the Tenth Street Superfund Site
in Oklahoma City, Oklahoma. A public meeting was held in Oklahoma City on July 29,
1993, regarding the proposed plan by EPA. At this meeting public concerns were expressed
that the installation of a cap on the site was inappropriate because of the possible occurrence
of catastrophic flooding or ground water contamination.
Site History
The Tenth Street site was operated at 3200 ME Tenth Street in Oklahoma City as a salvage
yard from 1959 until 1979 by an individual who reclaimed electrical transformers and
capacitors containing polychlorinated biphenyls (PCBs). A second individual then operated
an auto salvage yard on the site until 1985. EPA detected PCBs in the soil on the site in
sampling events from 1983 through 1985. They also found other compounds present in
drums on the site. In August of 1985, EPA began an emergency response action and
decontaminated and relocated the auto salvage operation, removed and disposed of electrical
equipment and the drums that were on the site. Contaminated soils were consolidated on
the site and a temporary clay cap was placed over the contaminated soils. Vegetation was
established on the cap and fencing was installed around the site to limit access.
In 1987, EPA added the site to the National Priorities List (NPL) to determine whether any
further action was necessary. EPA completed a remedial investigation and a feasibility
study for the site in 1989. The Agency chose an innovative technology called KPEG that
would reportedly destroy the PCBs by chemical dechlorination. A remedial design was
started by EPA for this remedy. The KPEG process was also implemented at two other
Superfund sites in New York and Texas that were contaminated with PCBs. Significant
problems were encountered with the KPEG process, and EPA discontinued the imple-
mentation of KPEG at these two sites and chose different alternatives. Subsequently, EPA
terminated the remedial design for the 10th Street Superfund Site.
Alternatives Presented by EPA
EPA is now in the process of choosing a new remedy. The alternatives that have been
presented by EPA for consideration include:
Alternative 1 - No Action
Estimated capital cost - $2,500
Alternative 2 - Capping in Place
Estimated capital cost - $407,800
(This is the alternative preferred by EPA)
Alternative 3 - Excavation and Offsite Disposal
Estimated capital cost - $5,507,600
(The off site disposal is by landfilling the contaminated soil)
Alternative 5 - Excavation and Onsite Thermal Treatment and Disposal
Estimated capital cost - $11,068,600
(A mobile incinerator would be placed on the site to treat the contaminated soil)
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Alternative 6 - Excavation and Offsite Thermal Treatment and Disposal
Estimated capital cost - $34,207,100
(Contaminated soil would be shipped to a permitted commercial incinerator)
DEO Evaluation
While the Tenth Street site was being operated as a salvage yard, actual exposure of salvage
yard workers and customers to PCBs either was occurring or was highly likely. The relo-
cation of the salvage yard and the installation of a temporary cap eliminated this exposure
route and significantly reduced the likelihood of any future exposure to the contamination.
The possibility that the PCBs could leach from the contaminated soils and affect groundwater
is highly unlikely. The PCB contaminated soils were exposed on the surface for many years
before the temporary clay cap was placed over them, and at the time of the EPA studies no
groundwater contamination had yet occurred. PCBs bind to soils very strongly and do not
mix well with water. Therefore, they are not expected to pose a threat to groundwater. DEQ
agrees with the concerns expressed at the recent public meeting that too much time has
elapsed since the groundwater elevations have been checked and groundwater samples have
been taken. We believe that EPA should perform these tasks in the very near future. If a
permanent cap is constructed over the contaminated soils, long term groundwater monitoring
will be conducted to observe whether any groundwater impacts occur in the future. The
five year review of the remedy, conducted by EPA, will determine whether the remedy is
still adequately protective of public health and the environment.
The concerns regarding the possible effects of flooding on the site are understandable given
the recent problems of flooding along the Mississippi River and some of its major tributaries.
It should be noted that the Mississippi River and its tributaries drain much larger areas with
higher precipitation rates than does die North Canadian River. The map of the area prepared
by the Federal Emergency Management Agency (FEMA) does indicate that the Tenth Street
site could be in the 100-year flood plain. However, EPA has consulted with the Corps of
Engineers and the City Engineer for Oklahoma City who both stated that the North Canadian
River was channelized to contain a 100-year flood event. This means that the site should
no longer be in die current 100-year flood plain.
Another concern expressed at the public meeting regarding the effects of flooding was that,
under saturated conditions, the PCBs might move into the groundwater. This is highly
unlikely because the movement of PCBs through the subsurface is not dependent upon
saturated conditions, but is dependent upon the characteristics of PCBs. The large molecular
size of PCBs and their very strong attraction to organic carbon present in soils are factors
which effectively limit PCB migration in the subsurface. PCB contaminated soils on the
site were periodically exposed to rainfall for many years, and the investigation of the site
revealed no evidence of the migration of PCBs into groundwater.
The low degree of risk presently posed by the site does not justify the selection of any
alternative put forth by EPA other than Alternative 2 - Capping In Place. The other alter-
natives proposed by EPA are not justifiable for the Tenth Street site. Alternative 1 - No
Action, is not acceptable because the present cap on the site is temporary in nature.
Alternative 3 - Excavation and Offsite Disposal is not useful because it merely moves the
waste from one location to another without achieving any significant improvement in
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environmental protection. Alternatives 5 and 6 involve incineration, which is currently a
controversial technology and most incineration projects face a great deal of public oppo-
sition. Although incineration would destroy the PCBs, it would be at an enormous cost that
is excessive considering the low risk posed by the small volume of contaminated soils on
the Tenth Street site. If EPA identifies any additional effective and cost-efficient technol-
ogies to remediate the site, the DEQ is willing to consider them.
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