United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R06-92/068
March 1992
PB93-964208
&EPA Superfund
Record of Decision:
Koppers (Texarkana Plant)
(Amendment), TX
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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 supplement, but adds no further appHcabte information to
the content of the document All supplemental material is, however, contained in the administrative record
for this site.
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Statutory Preference for Treatment as a
Principal Element is Met
and Five-Tear Site Review is Required
SITE KAME AMD LOCATION
Koppers TexarXana Site
Texarkana, Texas >
STATEMENT OF BASIS AND PURPOSE
This decision document is based upon the administrative record file
that supported the 1988 Record of Decision (ROD) and information
received since the signing of the 1988 ROD, which is set forth in the
attached administrative record file index. This document will
supplement the existing 1988 ROD, thus creating one inclusive ROD
which will govern the remediation activities planned for this site.
This amendment will enable the Environmental Protection Agency (EPA)
to implement the requirements contained in the fiscal year 1991 (FY91)
Appropriations Conference Report and Bill, and in the FY92
Appropriations Bill, concerning this site.
Under the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA), 42 U.S.C. Section 9617 and 40 CFR 300.435
(c)(2)(ii), as amended in 1986, EPA is required to develop this
document when fundamental changes to components of a selected remedy
outlined in an approved ROD are needed. This document is issued by
EPA as the Lead Agency responsible for remedying the contamination
problems that exist at this site.
The State of Texas concurs on this amended remedy.
ASSESSMENT OP THE SITE
Actual or threatened releases of hazardous substances from this site,
if not addressed by implementing the response action selected in the
1988 ROD and this Amended ROD, may present an actual or potential
threat to public health, welfare, or the environment.
DESCRIPTION OF THE AMENDED AND SELECTED REMEDY
Based on the Departments of Veterans Affairs and Housing and Urban
Development, and Independent Agencies Appropriations Act, 1991, Pub.
L. No.. 101-507, Title III/ 104 Stat. 1351, 1373 (1990), hereafter
cited as "FY91 Appropriations Bill",, the Joint Conference Report to
the FY91 Appropriations Bill, I?SR.: Conf. Rep. No. 101-900, 101st
Cong., 2ncl"Sess. 35 (1990), hereafter "Conference Report", and the
Departments of Veterans Affairs ali(|t; Housing and Urban Development, and
Independent Agencies Appropriatietis Act, 1992 Pub. L. No. 102-139,
Title III, 105 Stat. 736, 764 (1'99£), hereafter "FY92 Appropriations
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Bill", EPA is amending the existing 1988 ROD to include: 1)
of the Carver Terrace Community located on the Hoppers
Superfund site (Koppers) and, 2) relocation assistance for the
affected residents. This action will include reclassification of the
purchased residential; area to non-residential use, and affirmation
that the 100 parts per^million (ppm) total carcinogenic polynuclear
aromatic hydrocarbons (PAHs) action level is still appropriate to
remediate the site.
The ROD signed on September 23, 1988 calls for an action level for
removing greater than 100 ppm total carcinogenic PAHs in /the soil to
a depth of one foot, treatment of contaminated soils, and remediation
of contaminated ground1 water in the upper aquifer (Stratum I). The
contaminated ground water will be treated to levels .equal to the Best
Available Treatment Requirements (BAT) for the Organic Chemical,
Plastics, and Synthetic-Fibers Industry as specified "in the 1988 ROD.
Ground water cleaned to BAT will be reinjected into the aquifer along
with surfactants to -help recover the non-aqueous, phase liquids
(NAPLs). Ground water collection will continue until the NAPLs have
been recovered to the maximum "extent possible. This level will be
determined during the Remedial Design based upon pilot testing of the
collection and treatment system. After this pointf^is reached, the
ground water collection will cease and the ground water will be
allowed to naturally attenuate to background levels. A sampling
program will monitor the effectiveness of the selected remedy and
provide data necessary to trigger future corrective action, if
necessary. Based on information contained in the
Investigation/Feasibility Study (RI/FS), an estimated 19,400
yards of soil and 45 million gallons of groundwater will
treatment. The technology that will be utilized consists of
mechanical soil washing, and oil/water separation and either carbon
adsorption or fluidized carbon bed treatment of contaminated ground
water.
The 1992 Inclusive Amended Remedy (the 1988 ROD and this buyout
amendment), will be addressed in three operable units. The first
operable unit will involve purchasing the homes and providing
relocation assistance. The second operable unit will involve the
destruction, removal and disposal of the structures and debris to the
appropriate facility, the excavation and treatment of contaminated
soils, and replacement of the excavated areas with clean fill. The
third operable unit will be the treatment of the contaminated ground
water to standards contained in the 1988 ROD. The remediated area
will be limited to non-residential use through deed restrictions and
zoning changes. Also, the remediated area will be fenced and allowed
to return to its natural state until such time that the State of Texas
and/or the City of Texarkana plan to utilize the property consistent
with land use limitations called for in this ROD amendment.
This amendment to the 1988 ROD will not alter the intent of the 1988
ROD, with respect to the remediation of the site. However, it will
change the land use to non-residential, include institutional
controls, and permanently relocate the residents.
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DECLARATION :
. i! ,
This ROD amendment for the site is based on the FY91 Appropriations
Bill1 and Conference Report for EPA, the FY92 Appropriations Bill, and
community acceptance.
The remedy selected in 1988 along with this amendment, is protective
of public health and welfare and the environment, and complies with
Federal and State requirements that are legally applicable or relevant
and appropriate to the remedial action. The 1988 remedy utilizes
permanent solutions and alternative treatment technologies to the
maximum extent practicable, satisfies the statutory preference for
remedies that employ treatment that reduces toxicity, mobility, or
volume as a principal element, and is cost effective.
Because the 1988 remedy along with this amendment will result in
hazardous substances remaining on site (i.e., residual subsurface
soils contaminated with PAH compounds with concentrations less than
100 ppzn, and long term treatment of contaminated ground water), a
review will be conducted at least every five years after commencement
of the remedial action to ensure that the remedy continues to provide
adequate protection of public health and the environment.
B. J. Wynne Date
Regional Administrator
Region VI
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TABLE OF CONTENTS
I. INTRODUCTION ...................... 1
II. SITE HISTORY AND CONTAMINATION PROBLEMS ........ 1
1988 Selected ReMdy ............ ...... 3
III* liFpFQBq^ffflgvy ACTIVITIES AND OTHER BITB >
RELATED ACTIVITIES ........... ........ 3
IV. HIQHLIQHTfl OF COMMUNITY PARTICIPATION ......... 6
The Administrative Record ............... 6
VI. DESCRIPTION OF THE CHANGES ASSOCIATED
WITH THIS RECORD OF DECISION .............. 8
implementation of the Chang** ............. 9
VII. SITE RISKS ...................... 10
1988 Baseline Risk Assessment ........... , 1
1990 Revised Action Level for Residential Us* .... 11
Depth Criteria and Iner«a««d Voliui* Associated
with the 1990 Revised Action Level .......... 16
Reevaluation of the Action Level ........... 17
1988 and 1991 Risk Evaluations ............. 17
Governing Action Level for the Koppers' site ...... 24
VIII. 1992 INCLUSIVE AMUKDED REMEDY ............. 24
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AMENDED
RECORD OF DECISION
Koppers Texarkana
Superfund Site
Region 6
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R06-92/068
3. Recipient's Accession No.
4. Title and Subtitle
SUPERFUND RECORD OF DECISION
Koppers (Texarkana Plant)(Amendment),
First Remedial Action - Amendment
TX
5. Report D»te
03/04/92
7. Authors)
8. Performing Organization Repl No.
9. Performing Organization Nwne and Addreaa
10. Project/TMk/Work Unit No.
11. Contract(C) or Grant(G) No.
(C)
12. Spomoring Organization Name end Addrew
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report * Period Covered
800/000
IS. Suppta
ay Note
PB93-964208
4
16. Abstract (Limit: 200 words)
The 62-acre Koppers (Texarkana Plant) site is a former wood treatment facility located
in Texarkana, Texas. The site consists of a 34-acre residential area and a 28-acre
former sand and gravel operation. The entire site lies within a 100-year flood plain.
From 1910 to 1961, the Koppers Company treated wood onsite using PCP, creosote, and
metallic salts. After onsite operations ceased in 1961, the structures were removed
and the property was sold for residential and industrial development. In 1964, Carver
Terrace, Inc. developed the northern 34 acres of the site for residences. Kennedy Sand
and Gravel Company owns the remaining southern 28 acres, which operated as a sand and
gravel quarry from the late 1970s to 1984. In 1975, Mount Zion Missionary Baptist
Church purchased a small portion of the site from Carver Terrace Inc. to construct a
church. In 1980, an investigation conducted by both the state and the Koppers Company
identified onsite soil and ground water contaminated with PCP, arsenic, and creosote.
In 1985, EPA placed clean soil and sod on some of the yards in the subdivision as a
protective measure to reduce exposure to contaminated
(See Attached Page)
17. Document Analysis a. Descriptors
Record of Decision - Koppers (Texarkana Plant)(Amendment), TX
First Remedial Action - Amendment
Contaminated Media: soil, sediment, debris, gw
Key Contaminants: VOCs (benzene, toluene, xylenes), other organics (PAHs, PCP),
metals (arsenic)
b. Identifiers/Open-Ended Terms
c. COSATI FieWGroup
18. Availability Statement
19. Security Class (This Report)
None
20. Security das* (This Page)
None
21. No. of Page*
45
22. Price
(See ANSI-Z39.18)
See Instructions on Reverse
OPTIONAL FORM 272 (4-77)
(Formerly NT1S-35)
Department of Commerce
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EPA/ROD/R06-92/068
.Koppers (Texarkana Plant) (Amendment), TX
First Remedial Action - Amendment
stract (Continued)
soil. A 1988 ROD provided for onsite treatment of contaminated soil using soil washing
and treating the ground water and non-aqueous phase liquids (NAPLs) using oil/water
separation and carbon treatment. However, the remedial action was not initiated because
of a Congressional mandate set forth in the Conference Report to the FY92 Appropriations
Bill stipulating that EPA purchase homes located on the site and provide relocation
assistance to the residents. This 1992 ROD amendment appends the provisions of the
mandate to the remedy, as established in the 1988 ROD. The primary contaminants of
concern, as provided in the 1988 ROD, affecting the soil, sediment, debris, and ground
water are VOCs, including benzene, toluene, and xylenes; other organics, including PAHs
and PCP; and metals, including arsenic.
The amended remedial action for this ROD includes implementing all treatment actions
provided for in the 1988 ROD, which include onsite soil washing as well as treatment of
ground water using an oil and water separator and granular activated carbon treatment
purchasing onsite residences; permanently relocating affected residents; demolishing
homes and removing and disposing of debris offsite; implementing institutional controls,
including deed and land use restrictions; and reclassifying the property from residential
to non-residential use. The estimated amended present worth cost for this remedial
action is $12,400,000, which includes an annual O&M cost ranging from $316,200 to
$329,200 for 30 years.
PERFORMANCE STANDARDS OR GOALS:
hemical-specific clean-up goals remain the same as those provided in the 1988 ROD. Soil
'clean-up goals include excavation to a 100 mg/kg action level of total carcinogenic PAHs
based on a risk level between 10-6 and 10-4. Ground water clean-up goa'ls are not
provided but were based on Best Available Treatment Requirements (BAT) for the Organic
Chemical, Plastics, and Synthetic Fibers Industry.
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LIST OF FIGURES
FIGURE 1 SITE AREA MAP 2
FIGURE 2 CARCINOGENIC PAHS 12
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TABLE 1
TABLE 2
TABLE 3
x
TABLE 4
TABLE 5
LIST OF TABLES
1988 Potential Risks for Carver Terrace Soils
if Site is Remediated to 100 ppm Carcinogenic
PAHS (Assumes Residential Usage) 13
1990 Revised Remediation Goals
Assuming Residential Use 14
1988 Potential Risks for Carver Terrace Soils
if No Action Performed at the Site . . . . i
1991 Evaluation of the 100 ppm Action Level
for Industrial Use .'
1991 Risk at 100 ppm Carcinogenic PAH Chemical
Concentration in Soil
18
19
23
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LIST OF EXHIBITS
EXHIBIT 1 Commercial/Industrial Soil - Carcinogenic
Effects 21
EXHIBIT 2 Soil to Air Volatilization Factor 22
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LIST OF ATTACHMENTS
ATTACHMENT 1 - COST EVALUATION OF THE SELECTED REMEDY
ATTACHMENT 2 - RESPONSIVENESS SUMMARY
ATTACHMENT 3 - STATE OP TEXAS CONCURRENCE LETTER
ATTACHMENT 4 - AMENDED ADMINISTRATIVE RECORD INDEX
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DECISION SUMMARY
FOR THE
KOPPER8 TEXARKANA SITE
TEZARXAMA, TEXAS
I. INTRODUCTION
This Amended Record of Decision (ROD) presents the specific changes
that will become a part of the selected remedy discussed in the
Koppers Texarkana site ROD signed on September 23, 1988. Under the
Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA), 42 U.S.C. Section 9617 and 40 CFR 300.435(c)(2)(ii), as
amended in 1986, the Environmental Protection Agency (EPA) is required
to develop this document when fundamental changes to components of a
selected remedy outlined in an approved ROD are needed. This document
is issued by EPA as the Lead Agency responsible for remedying the
contamination problems that exist at this site.
The Koppers Texarkana site is located in a 100 year flood plain, in
Texarkana, Texas, approximately one mile vest of downtown Texarkana.
The site consists of 62 acres and is a former wood treatment facility
which began operations in 1910. The operation area consisted of a
drip track, treated and untreated wood storage areas, wood treating
cylinders, chemical storage tanks, and a waste water lagoon
(Figure 1). The chemicals used to treat the timber included
pentachlorophenol (PCP), creosote, and metallic salts. Operations
ceased in 1961, the structures were removed, and the property was
later sold for residential and industrial development. During 1964,
Carver Terrace, Inc. purchased 34 acres and subsequently constructed
79 homes on the northern half of the site, which is known as the
Carver Terrace subdivision. The remaining 28 acres on the southern
half of the site were sold to the Kennedy Sand and Gravel Company
which mined sand and gravel from the late 1970's to 1984. In 1975,
Mount Zion First Missionary Baptist Church purchased a half-acre tract
on the southern half of the site from Carver Terrace, Inc. and built
a church.
In 1980, the State of Texas and the Koppers Company found that the
soil and ground water were contaminated with chemicals commonly used
to preserve wood; PCP, arsenic, and creosote. In 1984, EPA placed the
Koppers Texarkana site on the National Priorities List.
As a protective measure in 1985, clean soil and sod were placed on
some of the yards in the subdivision to prevent residents from being
exposed to contaminated soils until the remedial action is
implemented. A Remedial Investigation and Feasibility study (RI/FS)
was also conducted on the site in February 1985. The RI determined
the types, amounts, and location of the contaminants. The FS
identified and screened remedial alternatives for site remediation
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JDO fl, fQ QOQQOn
•a
j-
CiD
i
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and analyzed in detail the technology and costs of the alternatives.
A risk assessment was also conducted to define the pathways of
potential exposure to contaminants and establish action levels for the
soil that are protective of public health.
1988 8«l«Ct«d R«B«4y
The ROD signed on September 23, 1988, calls for removing greater than
100 parts per million (ppm) total carcinogenic polynuclear aromatic
hydrocarbons (PAHs) in the soil to a depth of one foot, treatment of
contaminated soil, and remediation of contaminated ground water in the
upper aquifer (known as Stratum I). It assumes the residents will
continue to reside in the Carver Terrace subdivision, and deems the
100 ppm action level to be protective for residential use.
Contaminated ground water is to be treated to levels equal to the Best
Available Treatment Requirements (BAT) for the Organic Chemical,
Plastics, and Synthetic Fibers Industry. Ground water cleaned to BAT
will be reinjected into the aquifer along with surfactants to help
recover the non-aqueous phase liquids (NAPLs). Ground water
collection will continue until the NAPLs have been recovered to the
maximum extent possible. This level will be determined during the
Remedial Design based upon pilot testing of the collection and
treatment system. After this point is reached, the ground water
collection will cease and the ground water will be allowed to
naturally attenuate to background levels. A sampling program will
monitor the effectiveness of the selected remedy and provide data
necessary to trigger future corrective action, if necessary. The 1988
ROD estimated that approximately 19,400 cubic yards of soil and 45
million gallons of ground water will require treatment. The
technology that will be utilized consists of mechanical soil washing,
and oil/water separation and either carbon adsorption or fluidized
carbon bed treatment of contaminated groundwater. The 1988 projected
cost to implement this remedy is $6.4 million.
III. ENFORCEMENT ACTIVITIES AMD OTHER SITE RELATED ACTIVITIES
During November 1989, EPA initiated the negotiations for implementing
the 1988 ROD to conduct the Remedial Design/Remedial Action (RD/RA)
for the Koppers site with several potentially responsible parties
(PRPs). However, in February 1990, Region 6 suspended the RD/RA
negotiations with the PRPs in order to reevaluate the action level for
the residential portion of the site. This decision was primarily
based upon the findings discovered during a review of the 1988 risk
assessment that was developed for the site. The 1988 risk assessment
was developed in compliance with EPA risk assessment guidelines in
effect in 1988. Upon review in 1990, it was observed that the
exposure assumptions used to derive the action level for contaminated
soil in 1988 were not reflective of a residential subdivision occupied
by residents on a continuous basis, and therefore needed further
refinement. Furthermore, revising the 1988 action level using 1989
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guidelines would provide a more protective action level. Through
use of a fact sheet, a door to door visit with the residents that
conducted on April 24-25, 1990, and a workshop that was held on April
26, 1990, Region 6 informed the public that the Agency intended to:
1) revise the action level established in the 1988 ROD for the
residential area, to a level that was reflective of a residential
subdivision that is occupied by residents on a continuous basis, and
2) separate the RD/RA into two phases. Phase I consisted of a fast
track removal in which contaminated soil in the Carver Terrace
subdivision would be excavated and replaced with clean fill. Phase
II would have been the actual treatment of the contaminated soil and
ground water.
Upon reevaluating the data collected from the Remedial Investigation
and applying 1989 exposure assumption guidance, EPA derived the 1990
revised action level for remediating the residential portion of the
site. EPA determined the 1990 revised action level to be .33 ppm
benzo(a)pyrene equivalent for a residential area. This level provided
the necessary protection of human health and eliminated the potential
threat of long term exposure from contaminants in the subsurface
soils.
Also during the month of April 1990, the Agency for Toxic Substances
and Disease Registry (ATSDR) issued a health assessment for the
Koppers site. In response to concerns raised by the citizens, Members
of the United States Congress reviewed this report to determine if
there was a need to purchase the property of the residents.
EPA and ATSDR have always agreed on the long term health threats pose
by the site. The concerns viewed by the citizens stemmed from the
interpretation of language contained in ATSDR's April 10, 1989, health
assessment of the site. Specifically, ATSDR's health assessment
stated "Long-term exposures to contaminated soils in the residential
area pose a potential health risk for ingestion and dermal absorption
of soil contaminants". The assessment further stated that "the
remedial action previously taken by EPA to safeguard the health of
residents until final cleanup, is not sufficiently protective of
public health".
The remedial action ATSDR referred to, is actually a removal action
that was completed by EPA in 1985. This removal action consisted of
removing soil in yards that had concentrations of benzo(a)pyrene
greater than 325 ppm, replacing with clean fill and then resodding.
This action alleviated any imminent and substantial endangerment by
acting as a protective barrier until the final remedial action could
be taken. ATSDR's statement that the removal action was not
"sufficiently protective" meant that further action or remediation
will be required to remove long-term threats, which EPA plans to do.
In the following months, Region 6 met with the primary PRP on several
occasions to discuss implementing the 1988 remedy utilizing the 1990
revised action level of .33 ppm benzo(a)pyrene equivalent. In August,
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this PRP submitted to EPA, a draft statement of work which discussed
the implementation of the fast track RD/RA excavation activities
(Phase I). This draft SOW assumed the residents would remain in the
subdivision. Through September 1990, Region 6 pursued plans to
implement the fast track removal of contaminated soils.
The cost projected to implement the original 1988 remedy as stated in
the ROD is approximately $6.4 million. The projected costs to
implement the remedy using the 1990 revised action level would have
increased the cost of remediation by an estimated cost of $1.173
million (see Attachment 1), bringing the total cost of remediation to
approximately $7.573 million. These costs assumed the residents would
remain in the subdivision.
EPA provided interested members of Congress with a copy of the new
proposed plan, including the 1990 revised action level with the
accelerated removal schedule, and advised Congress of the factors
which led EPA to conclude that the selected remedy was protective of
human health and the environment. However, in the Conference Report
to the FY91 Appropriations Bill, Congress called upon Region 6 to
purchase the homes located on the Koppers Texarkana Superfund site in
Texarkana, Texas, and provide relocation assistance to the residents.
The Conference Report embodied provisions of the FY91 Appropriations
Bill for EPA, among other federal agencies, which was signed into law
on November 5, 1990. EPA Region 6, in accordance with the
Congressional mandate set forth in this report, terminated efforts to
implement the 1990 revised action level for the residential portion
of the site, and instead, pursued measures to implement the buyout.
EPA issued an Amended Proposed Plan (Plan) to the public in January
1991, that: 1) identified the changes that would modify the selected
1988 remedy and 2) explained the reasons for amending the 1988 ROD
to include a buyout. A public meeting was conducted on January 22,
1991, to discuss this Plan and receive community input. The public
comment period started January 15, and was extended until April 1,
1991, to allow the primary PRP the opportunity to comment on the Plan.
The FY92 Appropriations Bill that was subsequently passed, requires
for EPA to implement the Koppers buyout. The FY92 Bill states,
"...notwithstanding any other provision of law, the Administrator of
the Environmental Protection Agency shall from funds previously
appropriated under this heading in Public Law 101-507, obligate up to
$5,000,000 for Koppers Texarkana Superfund site relocation.", FY92
Appropriations Bill, Pub. L. No. 102-139, Title III, 105 Stat. 736,"
763-4 (1990).
The Amended Proposed Plan of Action and this Amended ROD will not
alter the intent of the 1988 ROD, with respect to the remediation of
the site. However, there is a fundamental difference in that the
Amended ROD calls for a permanent relocation of the affected
population, and a change in the expected land use from residential to
non-residential. Accordingly, the cost associated with the
implementation of the amended remedy will change. In addition to the
existing $6.4 million remedy, the cost associated with the buyout is
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projected to be $5 million. Another cost is that cost associated witflP
demolition of the homes and removal and disposal of the structures and
debris to the appropriate facility (see Attachment 1). Thus, the
charge associated with this activity is projected to cost $960,000.
The amended remedy will consist of the provisions previously
established in the 1988 ROD, and will include a buyout, the relocation
of residents, reclassification of the land use of the residential
portion of the site, demolition of the homes, and removal and disposal
of the structures and debris in the appropriate facility. The
remediated area will be limited to non-residential use through deed
restrictions and zoning changes. Also, the remediated area will be
fenced and allowed to return to its natural state until such time that
the State of Texas and/or the City of Texarkana plan to utilize the
property consistent with land use limitations called for in this ROD
amendment. The total estimated cost required to implement the amended
remedy is $12.4 million.
IV. q[JQ*ffrT<;gT8 OF COMMUNITY PARTICIPATION
The Amended Proposed Plan for the Koppers Texarkana site was released
to the public on January 9, 1991. This document and the Amended ROD
will be included in the administrative record. Notice of the public
meeting on the Amended Proposed Plan of Action was published in the
Texarkana Gazette on January 13, 1991. The public meeting was held
on January 22, 1991, and the public comment period started January
1991 and ended April 1, 1991. At the meeting, representatives
EPA and the U.S. Army Corps of Engineers (COE) discussed the
contents of the Amended Proposed Plan, the time frame associated with
the buyout and RD/RA activities, and the role the COE is expected to
have when the buyout is implemented. Afterwards, both agencies
entertained questions pertaining to the buyout. Representatives of
the Texas Department of Health and the ATSDR were present and answered
questions concerning the health study that would be performed in the
community in March 1991. Representatives of the Texas Water
Commission also attended this meeting and were available to answer
questions. A court reporter was present to transcribe the meeting,
and a copy of the transcript is included in the Administrative Record
file. A response to the comments received during this period is
included in the Responsiveness Summary (see Attachment 2).
The Administrative Record
This Amended ROD and the information received after the 1988 ROD was
signed in September 1988, will be included in, and become a part of,
the Administrative Record file.
The Administrative Record file for the Koppers Texarkana site provides
a step by step summation of all of the actions that have been
conducted at this site. It also supports and provides the basis for
the Agency's decision in selecting and amending the 1988 remedy. The
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record file is available for review at the EPA office in Dallas and
at the following repositories:
Texarkana Public Library Monday - Wednesday
600 West Third Street 9 a.m. until 9 p.m.
Texarkana, Texas 75501 Thursday - Saturday
(214) 794-2149 9 a.m. until 6 p.m.
Texas Water Commission Monday - Friday
Library - Basement 8 a.m. until 5 p.m.
17100 Congress /
Stephen F. Austin Bldg.
Austin, Texas 78711
(512) 463-7834
V. BA8I8 POR ISSUING THE AKgHDED ROD
It has long been the belief of many of the residents of this area,
that this site is affecting their health. The Carver Terrace
subdivision is located on the Koppers Texarkana Superfund site, which
is situated in a low lying area that is part of a 100-year flood
plain. This particular subdivision has been plagued by numerous
floods because of its location in a flood plain and because of its
lack of a proper drainage structure. Severe floods, compounded by the
fact that this community was built on a Superfund site, have
heightened the fears of the residents who believe they are being
exposed to hazardous substances.
Despite the efforts made by the Agency to assure the community that
a short-term health threat does not exist at the site, the community
continued to express their concerns involving the impact that the site
was having on their health to various city, state and federal
government officials. Community grievance intensified with the delays
the Agency experienced in implementing the RD/RA, the amount of time
that had lapsed before the community obtained a copy of the ATSDR
health assessment for the Koppers site, and the perceived
inconsistency of ATSDR's assessment of the site, with EPA's own
evaluation. Attempts were made by both EPA and ATSDR representatives
to discuss and resolve the perceived inconsistency viewed by the
residents and citizens concerning this assessment, but all efforts
were unsuccessful. In response to the community's urgency for a
buyout, Congress reviewed ATSDR's assessment for the site and amended
the Appropriation Bill for the Departments of Veterans Affairs and
Housing and Urban Development and Independent Agencies to include $5
million for the purchase of the homes on this Superfund site and
relocation assistance for the residents. The decision to amend the
1988 ROD is based on the contents of the Conference Report to the FY91
Appropriations Bill, the language requiring EPA to conduct a buyout
which is contained in the FY92 Appropriations Bill, and community
acceptance.
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VI. DESCRIPTION OF THB CHAMQB8 ASSOCIATED
The buyout amendment will require certain components of the remedy
selected in 1988 to change. First, the original ROD and the revised
action level for the residential portion of the site that was under
consideration, were designed to implement the remedy selected in 1988
with the intent that the residents would continue to live in the
subdivision. Under this buyout, the residents will be permanently
relocated. Another change associated with this buyout is that future
use ofx the residential property will be changed to disallow any
further residential development, once the existing homes have been
removed. Reasons for this measure are: 1) the remediation that will
be implemented on the property will leave residual contaminants in
subsurface soil, that would not be protective for long term
residential use, 2) the site area is prone to frequent flooding,
therefore, future development is not advised unless measures are taken
to prevent flooding, and 3) the City of Texarkana and the community's
desire that the area not remain residential.
During a meeting conducted on January 31, 1991 in Texarkana, Texas,
representatives of EPA, the Texas Water Commission, the General Land
Office for the State of Texas, and the City of Texarkana discussed
potential land uses for the property once the buyout was completed.
The City expressed at this meeting and on several other occasions that
they would not support future residential development of the property,
because of the flooding problem. However, the City does want th
possibility of using the land for industry, and stated it would
willing to assist in zoning the property for non-residential use afte
the remedial action is complete. The institutional control of zoning
that the City could provide is considered important to insuring that
future land use be non-residential.
By classifying the property as non-residential use, the action level
of 100 ppm carcinogenic PAHs would allow for industrial, trespassers,
wetlands or abandonment scenarios. However, if the property is to be
utilized in the future for industrial or commercial purposes it is
highly advised that flood protection be provided since this remedy
does not provide for any such protection.
The classification of the residential portion of the site will be
changed to non-residential use. This classification will facilitate
implementation of the amended remedy, and enable the State of Texas
(which will accept title to the former residential property) to
utilize the remediated property consistent with the land use
limitations called for in this.ROD amendment. EPA will work closely
with City and State officials'to ensure that their concerns on any
phase of the remediation are addressed consistent with the NCP. Also,
EPA will work with the State of Texas and the City of Texarkana to
have this property reclassified. Finally, EPA has reevaluated the
effectiveness in utilizing the 1988 action level of 100 ppm
carcinogenic PAHs, to remediate the reclassified portion of the site.
8
-------
The evaluation confirmed the 1988 action level is acceptable for non-
residential use; consequently, the basic approach to contaminant
remediation in the 1988 remedy will not change.
In summary, the two fundamental changes from the 1988 ROD are:
1) the buyout of the Carver Terrace Community, including relocation
assistance to the residents, demolition of the homes, and removal and
disposal of debris in the appropriate facility, and 2) the
reclassification of the property from residential to non-residential
use, and the affirmation that the 100 ppm carcinogenic PAHs action
level is still appropriate to remediate the site, and will provide
long term protection of human health, and the environment.
Implementation of the Changes
To implement the buyout, using Fund monies, the Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA) as
amended by the Superfund Amendments and Reauthorization Action of 1986
(SARA) requires the State to match 10 percent of the funds, and agree
to accept title to the property in question, on or before the
completion of the remedial action. The Texas Water Commission signed
the Superfund State Contract (SSC) on February 26, 1992. The SSC
represents the State's assurance that it will accept title to the
property. The EPA has designated the COE through an Interagency
Agreement that was approved May 13, 1991, to implement the relocation
of the residents residing in the Carver Terrace Community and the
purchase of this real estate. The COE will be the lead Agency for
this portion of the project, and EPA will be the supporting Agency.
Once the acquisition process is initiated, EPA will resume the lead
on activities associated with the remediation of this Superfund site.
Such activities will include: negotiating with the responsible
party(s) to reimburse the Fund for the buyout; resuming negotiations
to allow the responsible party(s) to finance the remediation of soil
and ground water contamination; coordinating with various State and
government agencies to insure that their concerns associated with this
site are addressed consistent with the NCP; developing and finalizing
plans that will be used to implement the 1988 ROD as amended; and,
remediating the site. These activities will be performed during the
same time frame that the COE executes the acquisition process.
The COE projects that it will take 9 to 10 months to acquire the
property. In some instances, similar actions have taken as long as
two years. EPA's time frame associated with the RD/RA negotiation
period may range from 90 to 150 days, achieving approved work plans
may take 6 to 10 months, and remediation of contaminated soil may take
18 months to 3 years. The period of time required to complete ground
water remediation has not been determined. However, the ground water
and Wagner Creek monitoring program will continue for at least 30
years, unless it can be shown during the remedial action that a
shorter length of time is appropriate.
Until the purchases of the homes are completed, the implementation of
-------
the Remedial Action cannot be initiated. During the period that
COE coordinates and implements the measures necessary to purchase
homes/ EPA will be negotiating and finalizing activities associated
with the final remediation for the site with the responsible party(s).
Health and Safety Plans, the Remedial Design, the air monitoring
program, etc. for the site can be developed while the buyout is being
conducted. Moreover, EPA expects the ground water remediation
measures to proceed concurrently with response activities associated
with operable unit 2.
The RD/RA will be addressed in three operable units. / The first
operable unit will involve purchasing the homes and providing
relocation assistance. The second operable unit will involve the
destruction, removal and disposal of the structures and debris in the
appropriate facility, excavation and treatment of contaminated soils,
and replacement of the excavated areas with clean fill. The third
operable unit will involve the treatment of the contaminated ground
water. The remediated area will be limited to non-residential use
through deed restrictions and zoning changes. Also, the remediated
area will be fenced and allowed to return to its natural state until
such time that the State of Texas and/or the City of Texarkana plan
to utilize the property consistent with land use limitation called for
in this ROD amendment. Operable units 2 and 3 will be performed
simultaneously, and initiated at the completion of operable unit l.
VII. BITE RISKS
The intent of this assessment is to provide a discussion and basis
the succession of risk evaluations that were performed for the Koppers
Superfund site. Specifically, this assessment will explain how the
1990 revised action level for contaminated soil on the residential
portion of the site was derived, and, given the fact that a buyout
will be performed, confirm that the 1988 action level of 100 ppm
carcinogenic PAH is protective of human health for non-residential
use, and the environment.
In 1985, a RI was conducted at the Carver Terrace subdivision. The
results of samples collected from yards showed the highest
concentrations of PAHs existed in soils located in the former
operation and drip track areas of the old wood preserving facility.
This included the yards on the south side of West Third Street,
several lots along Travis Street, and several lots bordered by Fannin
street and Nettie street which remain undeveloped. To reduce the
short tern exposure created by these contaminants, protective soil/sod
barriers were installed in those areas that had elevated levels of
surface contamination. Approximately 24 residential lots required a
protective soil/sod barrier. Sampling results also indicated that
lower concentrations were more widespread across the site. This is
possibly due to the grading conducted on the residential portion
during the development of the subdivision.
10
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1988 Baseline Risk Assessment
A Baseline Risk Assessment was conducted on the Koppers Texarkana site
utilizing data gathered from the RI. In the 1988 Koppers assessment,
PAHs were determined to be the class of chemicals of concern for the
site. In general, PAHs consist of a number of chemicals, of which the
carcinogenic PAHs represent a class of seven chemicals. At present,
benzo(a)pyrene is the only chemical of the seven chemicals that has
an interim cancer potency factor and was therefore used as a
representative of carcinogenicity of this group of PAH chemicals, to
determine the risk posed by the contaminated soils, as well as the
action level for remediating the site. Upon reviewing the RI data,
benzo(a)pyrene toxicity value was used to represent carcinogenic PAHs
as a class of chemicals, and was used as the basis for the 1988 risk
assessment for the site (Figure 2).
The 1988 assessment determined that an action level for the entire
site of 100 ppm total carcinogenic PAH for soil exposure had an
additional cancer risk of 3 x 10"5 (Table 1), assuming no relocation
of residents (i.e. residential use). The risk of cancer 3 x 10'5
means that three additional people in their lifetime (70 years), out
of one hundred thousand residents living on the remedied area will
have a statistical chance of developing cancer from the site. By
comparison, the national risk of developing cancer over a 70 year life
span is estimated at 2 x 10"1, or one chance in five. It is EPA's
policy to evaluate remedial options that will result in remedying
Superfund sites so that the risk from developing cancer is between one
in ten thousand (1 x 10'4) to one in one million (1 x 10"6).
The action level established for this site was in compliance with the
risk assessment guidelines in effect at the time the RI was conducted.
However, in reevaluating the action level of 100 ppm total
carcinogenic PAHs for soil on the residential portion, the Agency
determined that the exposure assumptions used to derive this action
level were not reflective of a residential subdivision that is
occupied by residents on a continuous basis, and therefore needed
further refinement. For this reason and the fact that the 1988 action
level would not provide adequate protection for residential use (1.5
x 10"3, Table 2), EPA revised the action level for the residential
portion of the site to be consistent with the present residential use.
New guidance was also a factor in reevaluating the 1988 action level,
as well as EPA's desire to further protect the residents at the
Koppers' site.
1990 Revised Action Level for Residential Us*
In calculating both the original and revised action level, benzo(a)
pyrene was used as the representative carcinogenic PAH because it is
one of the most toxic compared to the other carcinogenic PAHs. The
exposure scenario used was based on residential use for present and
future land use. The revised remediation goal considered the
11
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KOPPERS SUPERFUN'D SITE
C.COC?
O
N*S
ffi
0.0006 -
0.0005 -
c.ooo*-
O.OOC3 -
O.OOC2 -
r 7
Figure 2 Carcinogenic PAHs
1988 Baseline Risk Assessment
-------
TABLE 1
1988 Potential Risks for Carver Terrace Soils if(i)
Site is Remediated to 100 ppm Carcinogenic PAHs
(Assumes Residential Usage)
Contaminant
Carcinogenic PAHs(b)
PCP
Dioxin Equivalents(b)
Arsenic
Chromium
Copper
Lead
Mercury
Zinc
Maximum
Concentration
(mg/kg soil)
100
17
0.0000077
3.3
18
27
106
0.355
552
Total
Lifetime
Intake
(mg/kg/day)
2.58E-06
6.15E-06
.59E-13
.57E-06
.98E-06
.99E-06
.51E-05
.18E-07
.84E-04
6.
1,
5.
8.
3.
1,
1.
Hazard
Index
2E-04
Excess
Maximum
Lifetime
Cancer
Risk
= :•==:
3E-05
1E-07
2E-06
3E-02
3E-05
Contaminant
Carcinogenic PAHs(b)
PCP
Dioxin Equivalents*6*
Arsenic
Chromium
Copper
Lead
Mercury
Zinc
Average
Concentration
(mg/kg soil)
7.8
1.35
0.0000077
2.7
3.9
2.6
12.9
0.18
3.4
Total
Lifetime
Intake
2.01E-07
5.21E-07
6.59E-13
1.29E-06
2.70E-06
3.24E-06
1.33E-05
5.97E-08
5.37E-05
Hazard
Index
2E-05
Excess
Average
Lifetime
Cancer
Risk
2E-06
1E-07
2E-06
1E-02
4E-06
(t> Exposure reflects the scenario in the FS Report called
"Future Carver Terrace".
(b) Concentrations reflect present levels; degradation
reflected in intake calculations.
13
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TABLE 2
1990 Revised Remediation Goals
Assuming Residential Use
The remediation goal accounts for ingestion of potentially
contaminated soils.
IF(ingestion) - Sum [(SI * EF * ED) / (BW * AT)] -
Intake » IF * soil cone. /
Where: IF(ingestion) « Intake Factor from soil ingestion
SI « Age-specific Soil Ingestion Rate (RAGS and
OSWER Directive 9850.4)
EF = Exposure Frequency (days/year)
ED = Age-specific Exposure Duration (years)
BW = Age-specific Body Weight (Handbook)
AT - Averaging Time (70 years)
soil cone. * soil concentration
Age-specific exposure parameters for soil ingestion:
Age Class Body
(years) Weight (kg)
0
1
6
12
18
- 1
- 6
- 12
- 18
- 70
10
17
30
55
70
Ingestion
Rate (kg/ day)
0
0.0002
0.0001
0.0001
0.0001
Frequency
(days /year)
365
365
365
104
52
Duration
(years)
1
5
6
6
52
IF(ingestion) - Sum [(SI * EF * ED) / (BW * AT)]
» 1.3 x 10'8 kg/kg-day
Intake = 1.3 x 10'6 kg/kg-day * soil cone, mg/kg
Risk = IF (ingestion) * oral slope factor for b(a)p * soil cone.
Risk = 1.3 x 10'e kg/kg-day * 11.5/mg/kg-day * soil cone, mg/kg
Risk = 1.5 x 10'5 kg/mg * soil cone, mg/kg
14
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TABLE 2 - Continued
Soil cone, or Remediation Goal at 10"6 Target Risk Level is:
1 x 10"6 » 1.5 x 10"5 kg/mg * soil cone, mg/kg
Soil Cone.
or s /
Remediation Goal - 1 x 1CT6 / 1.5 x 10'5
= 0.07 mg/kg
Risk at a soil concentration of 100 mg/kg is:
Risk = 1.5 x 10'5 kg/mg * 100 mg/kg
• 1.5 X 10"3
The 1 x 10'6, l x 10'5, l x 10"4 target remediation goals are 0.07, 0.7,
and 7 mg/kg benzo(a)pyrene equivalents, respectively. These target
remediation goals are below or close to the contract-required
quantitation limit for benzo(a)pyrene of 0.33 mg/kg. A remediation
goal of 0.33 mg/kg benzo(a)pyrene equivalents would approach an upper
bound excess lifetime cancer risk of five in one million (5 x 10'6)
and be within EPA's acceptable risk range.
15
-------
protection of individuals living at the site for their entire lifetim
(70 years), including childhood exposure. The remediation goal also1
assumed no degradation of the carcinogenic PAHs in the soils, and a
gastrointestinal absorption factor of 1, accounted for ingestion of
potentially contaminated soils.
Remediation goal development used the Risk Assessment Guidance for
Superfund, Human Health Manual, Volume 1, Part A (RAGS - EPA/540/1-
89/002, December 1989) and the Exposure Factors Handbook (EPA/600/8-
89/043, March 1990). The interim oral slope factor for benzo(a)pyrene
is used as the representative carcinogenic PAH. The oral slope factor
for benzo(a)pyrene is under review by the Carcinogen Risk Assessment
Verification Endeavor (CRAVE) work group.
With the parameters established, the soil samples (0 to 2 feet) taken
from the residential portion were reevaluated to determine the
specific concentrations of all of the carcinogenic PAHs. Each
compound was given a toxicity rating expressed as an "equivalent
amount of benzo(a)pyrene". Adding the toxicities of each of the
compounds produced the sample's overall toxic equivalency to
benzo(a)pyrene. Adding the different PAH compounds in this manner
allowed EPA to characterize the possible risk posed by the site as if
it contained a single "equivalent" compound and, more importantly, to
establish a single remediation goal that encompassed a wide variety
of PAH compounds. The revised action level selected to remediate the
residential portion was 0.33 ppm benzo(a)pyrene equivalent which is
the contract-required quantitation limit (Table 2). This revisedj^
action level further reduces the likelihood of developing cancer, andflV
provides an upper bound additional lifetime cancer risk of five in one
million (5 x 10'6).
Depth Criteria and Increased Volua* Associated with the 1990 Revised
Action L«v«l
The 1990 revised action level for the residential portion affected the
initial projections made for the volume of soil requiring excavation,
the cost, and the time needed to conduct the excavation activities.
Unlike the one foot depth criterion established by the 1988 ROD, the
depth of excavation was to be governed by the results obtained from
the pre-excavation sampling exercise, and the possible interference
encountered from the shallow ground water aquifer. Technical
consideration would determine what method (ground water treatment or
excavation) to use to retrieve contaminated soils below a depth of
three feet. The existing data collected from yards where access was
granted was extrapolated to also project the quantity of contaminated
soil that possibly existed in yards that did not grant access. The
volume of soil targeted for excavation was approximately 23,765 cubic
yards. The cost associated with excavating and treating contaminated
soil was estimated to cost $1.173 million, and approximately 15 to 27
months would be required to complete the tasks associated with this
activity.
16
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Reevaluation of the Action Level
Implementation of the 1990 revised action level for the residential
portion of the site was suspended, based on the Conference Committee
Report on the FY91 Appropriations Bill, that contained language
calling for the buyout of homes on the Koppers Texarkana site and the
provision of relocation assistance to the residents. With approval
of this Bill, EPA redirected its effort to amend the 1988 ROD to:
include a property buyout, discuss the reclassification of the
residential portion of the site to non-residential use, and confirm
the 198* action level of 100 ppm carcinogenic PAHs is protective and
appropriate to remediate the area for non-residential use.
1988 and 1991 Risk Evaluations
Once the buyout is completed, institutional controls will be put in
place to prevent this property from being utilized for residential
use. The risk from 100 ppm carcinogenic PAHs falls within the 10'4 to
10"6 acceptable risk range given an industrial scenario only and not
for residential use. Though the area exists in a 100 year flood
plain, it can be used to facilitate proper drainage for the
surrounding area, and/or for industrial purposes, if flood protection
is provided. The risk from 100 ppm carcinogenic PAH does not fall
within the 10"4 to I0"e risk range for residential land use.
To ensure adequate protection of human health and the environment, EPA
reevaluated the risk posed by the site to determine if the 1988 action
level of 100 ppm total carcinogenic PAHs is appropriate given the
changes in classification and utilization of the property from
residential to non-residential use and industrial scenario
respectively.
In reevaluating the method used to derive the 1988 action level,
a comparison was performed between the guidance used in 1988, to
current guidance. The 1988 baseline risk from benzo(a)pyrene if no
remediation is performed is estimated to be 6 x 10'r (Table 3) .
However, when this risk was reevaluated using new guidance, it was
estimated to be 1.04 x 10'3 (Table 4). It was observed in the 1988
assessment that indicator chemicals or those chemicals which pose the
greatest potential public health risk were used as recommended by the
old Superfund Public Health Evaluation Manual (SPHEM - EPA 1986). As .
discussed in the Risk Assessment Guidance for Superfund, Human Health
Manual, Volume 1, Part A (RAGS -EPA/540/1-89/002, December 1989) which
replaces SPHEM, the new procedure requires the inclusion of all
chemicals of potential concern, and the exclusion of those chemicals
evaluated to be of no concern. A final list of chemicals is then
prepared for the quantitative risk assessment. The 1991 evaluation
used the interim oral slope factor for benzo(a)pyrene as the
representative carcinogenic PAH. The oral slope factor for
benzo(a)pyrene is under review by the Carcinogen Risk Assessment
Verification Endeavor (CRAVE) work group. Differing from the 1988
approach, biodegradation or the natural biological breakdown of the
17
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TABLE 3
1988 Potential Risks for Carver Terrace Soils if<4)
No Action Performed at the site
Contaminant
Carcinogenic PAHs Concentrations reflect present levels; degradation
reflected in intake calculations.
18
-------
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PAHs was not included in the 1991 evaluation since a conservative
approach was desired. In establishing the parameters for the 1991
evaluation, 25 years instead of 40 years exposure duration and an
inhalation rate of 20 m3/day instead of 15 m3/day were used in
accordance with the updated guidance on Standardized Exposure
Parameters (Risk Assessment Guidance for Super fund, Volume I: Human
Health Evaluation Manual, "Standard Default Exposure Factors", OSWER
Directive 9285.6-03, March 25, 1991). It was noted during the review
of the 1988 risk assessment that 5 years was used as -the exposure
duration for workers. According to current standards (OSWER Directive
9285.6-t)3), an individual is assumed to work 25 years at the same
location (95th per cent ile; Bureau of Labor Statistics, 1990). A
gastrointestinal absorption factor of 1, accounted for ingestion of
potentially contaminated soils in the 1991 evaluation for a
commercial/ industrial exposure scenario. Inhalation and ingestion
potency factors for benzo(a)pyrene as cited by the Health Effect
Assessment for PAHs (September 1984) are 6.11 (mg/kg/day) '' and 11.53
(mg/kg/day) ~1 respectively. The reduced default equation for
carcinogenic effects was used to determine the risk at 100 ppm total
carcinogenic PAH chemical concentration in soil assuming
commercial/ industrial land use (see Exhibit 1 and 2) . The risk
associated with the action level of 100 ppm total carcinogenic PAHs
assuming industrial use, was found to be 2.0 x 10'4 using toxicity
values for benzo(a)pyrene (see Table 5). This risk falls above the
acceptable risk range discussed in the National Contingency Plan.
With the parameters established, the samples (0 to 2 feet) taken
the residential portion were reevaluated to determine the
concentrations of all of the carcinogenic compounds in PAHs found at
the site. Each compound was given a toxicity rating expressed as an
"equivalent amount of benzo(a)pyrene". Adding the toxicities of each
of the compounds produced the sample's overall toxic equivalency to
benzo(a)pyrene as opposed to the 1988 approach which treated all of
the compounds as being as potent as benzo(a)pyrene. Summing the
different compounds in this manner allowed EPA to characterize the
possible risk posed by the site as if it contained a single
"equivalent" compound and, more importantly, it established a single
remediation goal that encompassed a wide variety of PAH compounds.
A site specific risk assessment associated with the PAHs was also
performed. The risk was adjusted by using carcinogenic relative
potencies. The adjusted risk was found to be 22% of the risk
calculated by using the potency factor of benzo(a)pyrene for all
carcinogenic PAHs. The cancer risk associated with the 100 ppm
carcinogenic PAHs soil action level at Koppers superfund site was
calculated with these adjustments, and the risk was found to be 4.0E-5
(Table 4) . The site specific risk is well within the EPA's acceptable
risk range assuming an industrial/commercial scenario.
20
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Exhibit 1 _
COMMERCIAL/INDUSTRIAL SOIL - CARCINOGENIC EFFECTS
TR m §T. * C x 10"* toJmt » Ex ED s IB.., -f SF »
x ED x
n/VF * 1/PEFt
BW x AT x 365 days/yt
C (m^lcf; ritlc- =
based)
where:
BW x AT x 365 daytftr
: BW jt AT x 365 davs/Vr
TR .
SFj
SFB
BW
AT
EF
£D
VT
PEF
where:
Parameters
K.
K.C
OC
£FxEDx[(SF.x 10* ki/mg x IR^) + (SF, x IR^, x [1AT f 1/PEF])]
(6)
Parameters Deanhioe funim
. chemical coneemntioc te nil (mj/tg)
iwfet txoea.iDUJvKtual Efelioe cuctr mk
ichalatioo aacer Hope bctor ((mi^l^oy)'
onl ameer slope Actor ((tnjfcj-diy)"1)
aduft body wifi
iverapni tine (yr)
exposure fiequeaey
expenure duruioB (yr)
l io|ettioo rate (mf
workday inUalatioo me (m'/day)
(oil-to-air volatilisation betor
paniculate emissioo fiaor(m'/ks}
X1X1^ * (««•.)
Definition (units \
soil saturation concentration (mj/kg)
soikwaier partitioa coefficient (LtJ)
orgaaic carbOo partitioa coefficient (lAj)
organic carbon content of soil (fraction)
solubility (mg/Ixrttef)
soil moifiure content, expressed as a weight fraction
soil moisture content, expressed as l-waier/kf-soii
Default Value
. .
cbenucal-tpeofic
70 kg -
70 yr
2SOdayt/yr
25yr
SOmt
ebemieal^peciflc (MC Section 3 J.I)
4.63 s 10*ioVk| (see Section 1.3.2)
(6a)
Detauit Vaiue
ehemiCBl4peetflc, or X.. x OC
eheiaicaJ-cpeeifle
tite-ipecific. Or 0.02
cttemicaMpecific
t(te-ipectfic
lite-jpecifie
REDUCED EQUATION: COMMERCIAUINDUSTRIAL SOIL - CARCINOGENIC EFFECTS
Risk-based PRO
; TR • 1C4)
where
SF,
VF
[((5 x 10-*) x
• onl slope tactor in
• jonamtton Hope fiieior m
s ch«mksl4pecJfic ioil-to-air volatilization factor io m'/Vfi (tee Section 5J.1)
(6')
If PRG > C^, tbco let PRO » C» (where C^, * soil tatuntion concentration (mg/zf); see Equation (6a)
and Seotoc 33.1).
Exhibits 1 and 2 may be found in "Risk Assessment Guidance for Superfund,
Human Health Evaluation Manual—Part B, Development of Risk-based Remedial
Goals" (OSWER Directive 9285.01B).
-------
Exhibit 2
VF cm-Vies)
wn«re:
« O-Sx Vx
SOIL-TO-AIR VOLATILIZATION FACTOR
x fa 14 x«
(8)
, xEl
Sifcndvd default parameter values (hat can he used to reduce Equation (8) ate feted below. These represent "lypiaT
values w identified in • number of sources. For example, wbca wie-speciGc values are net available, the tenfih of a
side of ine contaminated area (LS) is assumed to be 45 m; this is based on a contaminated area of 0.5 acre which
approximates tbc >iee of an average residential tot. The "typical* value* LS. DK, and V are from EPA1986/ Typical'
value* for E, OC, and p, are from EPA 19&, EPA 19886. and EPA l9SSf. Site-«peeifk data should oe substituted
tor the default values listed below wherever possible. Standard values for cnemicai-spcciflc Dj, K. and K^ can be
Obtained by cailioj the Superfund Health Risk Tecbaieal Support Center.
Parameter
VF
LS
V
DH
A
P.
T
O.
K
OC
Definition
volatilization factor (m'/lcg)
length of side of contaminated area (m)
wind speed in mixio; zoue (mA)
diffusion height (m)
area of contamination (cm1)
effective diffusivity (enVs)
true soil porosity (unittesi)
toil/nir partition coefficient Cs soil/em1 air)
frefaup
4Sm
125 nvj
2m
2D.250,000 em2
true soil density or paniculate density
exposure interval (s)
molecular diffusely (cm:/»)
Henry't ttw constant (aun-m'/mon
soil^aier panition coefflcif nt (cnr/|]
organic carbon partition coeflicient (em1/!)
grpnk carbon content of soil (fraction)
0.35
(H/K() x 41, where 41 it a units
conversion saoor
2.651/cai1
IS x Vf i
chemicol4pecific
chemicaMpecific
chemical-specific, or
ehemicanpeciDc
dte-tpedfie, or QJOZ
x OC
PARTICULATE IMISSION FACTOR
PEF (afkS)
WtoC
Parameter
PEF
LS
V
DH
A
0.036
G
u.
u,
F(x)
• LSxVxDHxHOOi/hr
A
Definition funHsl
paniculate emission factor (m'/kg)
width of contaminated area (m)
wind speed in rnwng toot (ovs)
dilfusioa beifbt (m)
area of coBtamattion (m1)
respirable (netion fjto'-ftr)
fraction of vegetative cover (unltlew)
mean annual wind speed (fflA)
equivalent threshold value of wind speed
at 10 m (m»)
functioo dependent on UJU, (uajdess)
x looo tyke m
0.036 x (1-G) x (UJU,tf x F(X)
-
fjeftuit
4.63 x 10* ataf
45m
125 m/i
2m
2025 or*
0.036 i/m1-^
0
4JmA
IZSffl/k
0.0497 (determined using Cowherd 1983)
-------
TABLE 5
1991 Risk at 100 ppm Carcinogenic PAH
Chemical Concentration in Soil
Equations used:
Risk at Chemical concentration = (see Exhibit l)
in soil
Volatilization factor VF = (see Exhibit 2)
Soil water partition ,
coefficient (Kd) = Organic carbon partition coefficient (Koc)
X Organic Carbon Soil Content (2%).
Kd = Koc X OC = 5.5 X 106 X 0.02 = 110,000
Henry's Law Constant = 1.55 X 10'6
Benzo(a)pyrene = C20H12
0.001T1'75 X (1/M, + 1/M2)0'5
Molecular Diffusivity (Dt)
at 25°C P[( V,)1'3 + ( V2)1/3]2
where : T = absolute temperature (K)
M, & Mg = molecular weights of components 1 and 2 (g/mole)
V, & V2 = atomic diffusion volume of components 1 and 2
P = absolute pressure, atm.
17.42 X (0.044)0'5 X 110000
VF = ----------------------------------------------------------
[0.35 + (0.042 X 110000) /1. 55X10'6 ]°'5 X 0.044 X 1.55 X 10'6
VF = 1.08 X 108
Risk at Chemical « 100 X 250 X 25 X [(11.5 X 1E-6 X 50) + (6.11 X
Concentration 20 X (1/1080.DOOOO + 1/4630000000)]
in Soil _
70 X 70 X 365
Risk at Chemical
concentration = 2.0 X 10"4
in Soil
For a 10'6 cancer risk the clean up level is 0.5 mg/kg
For a 10"4 cancer risk the clean up level is 50 mg/kg
-------
Governing Action Level for the Coppers' Site
The 1988 action level of 100 ppm total carcinogenic PAHs will continue
to be utilized for the planned remediation of the Koppers Texarkana
Super-fund site because it provides an acceptable level of protection
for industrial scenario, and is protective of human health and the
environment. To determine conformance with this action level, the
concentrations for carcinogenic PAHs shall be summed and this total
compared to 100 ppm. Measured concentrations of the various
carcinogenic PAHs will be used rather than equivalent benzo(ajpyrene
concentrations.
VIII. 1992 INCLUSIVE >inntDgp REMEDY
This amendment does not change the basic approach for the remediation
of site contaminants as set out in the ROD signed on September 23,
1988. The remedy calls for an action level for removing greater than
100 ppm total carcinogenic PAHs in the soil collected to a depth of
one foot, treatment of contaminated soils, and remediation of
contaminated ground water in the upper aquifer (Stratum I). The
contaminated groundwater will be treated to levels equal to BAT
Requirements for the Organic Chemical, Plastics, and Synthetic Fibers
Industry. Ground water cleaned to BAT will be reinjected into the
aquifer along with surfactants to help recover the non-aqueous phase
liquids (NAPLs). Ground water collection will continue until
NAPLs have been recovered to the maximum extent possible. This
will be determined during the remedial design based upon pilot testing
of the collection and treatment system. After this point is reached,
the ground water collection will cease and the ground water will be
allowed to naturally attenuate to background levels. A sampling
program will monitor the effectiveness of the selected remedy and
provide data necessary to trigger future corrective action, if
necessary. Based on information contained in the RI/FS, an estimated
19,400 cubic yards of soil and 45 million gallons of groundwater will
require treatment. The technology that will be utilized consists of
mechanical soil washing, and oil/water separation and either carbon
adsorption or fluidized carbon bed treatment of contaminated
groundwater.
The amendment to the 1988 ROD will include: 1) a buyout of the Carver
Terrace Community, relocation assistance to the residents, and the
demolition of the homes and the removal and disposal of debris in the
appropriate facility, and 2) reclassification of the property from
residential to non-residential use, and affirmation that the 100 ppm
carcinogenic PAHs action level is still appropriate to remediate the
site, given the changed land use. EPA will work with the State of
Texas and the City of Texarkana to have this property reclassified.
The RD/RA will be addressed in three operable units. The first
operable unit will involve purchase of the homes and providing
24
-------
relocation assistance. The second operable unit will involve
destruction, removal and disposal of the structures and debris to the
appropriate facility, excavation and treatment of contaminated soils,
and replacement of the excavated areas with clean fill. The third
operable unit will be the treatment of contaminated ground water.
The remediated area will be fenced and allowed to return to its
natural state until such time that the State of Texas and/or the city
of Texarkana plan to utilize the property consistent with the land use
limitations called for in this ROD amendment.
The projected cost to implement this amended remedy is $12.4 million.
25
-------
ATTACHMENT 1 - COST EVALUATION OF THE SELECTED REMEDY
-------
TABLE A-l
BASELINE CAPITAL COSTS
EXCAVATION/SOIL UASN1NG *
COST COMPONENT QUANTITY
SI'E
PREPARATION
4.4
UNIT UNIT COST
ACRES
$1,450
TOTAL COST
$6,
380
COMMENTS
INITIAL MONITORING
SAMPLING
ANALYSIS
22
176
DAYS
SAMPLES
$400
$315
$8.
•55.
800
440
8 SAMPLES COLLECTED/DAY
8 SAMPLES/LOT ANALYZED
SOILS FROM THE CARVER TERRACE SUBDIVISION:
HJLK
SCIL
EXCAVATION
»
ON-SITE HAULING
SOLIDS FROM THE KENNEDY SAND AMD
LOAD
ON-SITE HAULING
HASHING TREATMENT SYSTEM:
TREATMENT SYSTEM HOB/DEMOB
TREATMENT EQUIP. RENTAL
(TREATED AT A RATE OF 2.5 TONS
PER HOUR 3 10 HOURS PER DAY)
CHEMICALS
UTILITIES
UAH WATER TREATMENT
OPERATION i SUPERVISION
AIR MONITORING
UCKFILLIHG OF TREATED SOILS
8400
8400
GRAVEL
160
160
1
12
1
1
1
1
12
8560
CY
CY
PROPERTY:
CY
CY
LP SUM
MONTHS
LP SUM
LP SUM
LP SUM
LP SUM
MONTHS
CY
$15
$3
$100
$3
$14,000
$58,000
$18.000
$11,000
$6.750
$165,000
$3,000
$3.00
$126,
$25.
siS,
I
$14,
000
200
000
I480
000
•696,000
1 FT DEPTH OVER 190,000 !
201 BULKING
/
FOUR 40-CY ROLL-OFFS
INCLUDES REACTORS,
TAWS, MIXERS.
HOPPER
[F;
$18,000
$11,000
$6.
750
$165,000
$36,000
$25,680
CARVER TERRACE SOILS AND
BULK SOLIDS; PLACED WITHIN
SITE
RESTORATION:
CLEAN BACKFlLL-dO")
SPREADING
SOD (2*)
HEALTH t SAFETY
7000
7000
21100
52
CY
CY
SY
WEEKS
$5.00
$2.00
$3.55
$4,000
$35,000
THE KSIG PROPERTY
ONLY FOR CARVER TERRACE
AREA
$14,000
$74,905
$208
.000
ONLY FOR CARVER TERRACE
AREA
MtS DURING INITIAL MONITOR-
ING AND EXCAVATION/TREATMENT
DIRECT CAPITAL COST
$1,542
.635
ENGINEERING I DESIGN (111)
CONTINGENCY (20t)
$169,690
$308,527
TOTAL CAPITAL COST
$2,020,852
APPROXIMATE TOTAL CAPITAL COST $2,021,000
* An action level of 100 ppn total carcinogenic PAHs was used in deriving the
cost.
-------
TABLE A-2
BASELINE CAPITAL COSTS
BCCAVATIO«/$QII UASNUO
.33pp« I«P CQUtVAUNCT CUAM-UP CUtTMU
con catpottvr cuAnim UNIT UNIT eocr TOTAL COST
SITS PREPARATION 11.77 ACRES $1,450 $17,067/
INITIAL NONITORIIIC
SANPUNO 59 OATS - $400 $23.400
ANALYSIS 470 SAMPLES $315 $148,050
SOILS FION THE CARVE! TERRACE SUBDIVISION
EXCAVATION ft ON-SITE MAUL 28518 CY $4* 8171,1C8
IUU SOILfit FMN TNI ONNEOT SAM) AND GUVIL PROPERTY:
LOAD
ON-Sm NAULIMO
SOIL WASHING TtlATMENT SYSTEM
TREATMENT ST$TCM NOS/OEMC4
TREATMENT EQUIPMENT RENTAL
CHEMICALS
UTILITIES
WAN WATER TREATMENT
OPERATION ANO SUPERVISION
AIR MONITORING
SACXFILLINC Of TREATED SOILS
SITE RESTORATION
CLfAN BACKFILL
SPREAD INC
HYDNONULOI
NEALTN ANO SAFETY
160
160
1
15
1
1
1
1
IS
10734
0745
11.77
11.77
41
et
a
IP SUM
idHTMS
LP SUN
LP SUM
LP SUM
LP SUM
MONTHS
CY
a
ACRES
ACRES
WEEKS
$100
$4
$23.327
$74,700
$30,000
$11,328
$11,247
$274,92?
$3,947
$4
$5
$750
$4,35*
$4,000
$14.000
•940
•23,327
$1.150,500
$30,000
•18.328
•11.247
SZ74.927
$59.505
$42.944
$118,825
$8,828
SSI. 270
•272,000
DIRECT CAPITAL COST S2.4U.48S
ENOIBEERIIM I DO1SN (11X) $248.233
COKTlNfiaa (20X1 $487.497
TOTAL CAPITAL COST $3.194,414
APPROXIMATE TOTAL CAPITAL COST $3,194,000
NOTE: The additional costs attributed to the 1990 revised
action level is approximately $1.173 million.
* EPA used a different cost estimate here than in Table A-l
for this activity. This revised estimate is more accurate,
-------
TABLE A-3
BASELINE CAPITAL OOSTS
FLU1DIZEO CARBON BED
COST COMPONENT
QUANTITY
UNIT UNIT COST
TOTAL COST
COMMENTS
SITE PREPARATION
WELL REPLACEMENT
SUBSURFACE DRAIN SYSTEM:
DRAINS INSTALL
FLOATING PUMPS
SUMP INSTALL
PIPING
RECHARGE TRENCHING (IN -SITU
SHALLOW TRENCH INSTALL
INJECTION PUMPS
PIPING
ELECT I INSTRUM
INJECTION TANK
CHEMICAL FEED SYSTEM
ANDL1NG OF EXCAVATED SOILS
EXCAVATE
ON-SITE HAULING
SROUNDWATER TREATMENT PLANT
SOIL FILL
SURVEYING
TREATMENT SYSTEM:
OFFICE/LAB
OIL/WATER SEP
FLUID BED REACT
PIPING/PUMPS
ELECTR t INSTRUM
ANCIL EQUIPMT
OTHER PROC TANKS
HEALTH t SAFETY
DIRECT CAPITAL COST
ENGINEERING t DESIGN (11X)
CONTINGENCY (20X)
TOTAL CAPITAL COST
1 LP SUM
9 WELLS
2100 LF
20 PUMPS
20 SUMPS
1 LP SUM
SOIL FLUSHING):
1500 LF
2 PUMPS
1 LP SUN
1 LP SUM
1 LP
1 LP Sun
85,000
85.000
850
83,000
83,000
88,000
825.00
83,500
835.000
820.000
810,000
85,000
85,000
845,000 1 REPLACEMENT PER 30 TEARS
8105,000
860,000
860.000
88.000
BASED UPON A 10,000 GPO
837,500 'INJECTION RATE
87.000
835.000
820.000
810.000
85.000
FROM TRENCH EXCAVATION:
2000 CY
2000 CY
815
83.00
830.000
86.000 HAULED ON SITE TO GRAVEL
PITS; TREATED VIA GR WATER
• PRELIMINARY EARTHWORK:
4000 CY
1 LP SUM
1 LP SUM
1 LP SUM
1 LP SUM
1 LP SUM
1 LP SUM
1 LP SUM
1 LP SUN
24 WEEKS
!«*»««««»«*»««*****•*
816
85,000
835,000
816,000
835,000
865.000
885,000
8101,000
865,000
84,000
864,000
85,000
835,000
816.000
835.000
865.000
885.000
8101.000
865.000
896,000 HIS OFFICER DURING EXCAVATION;
MhJ AND RESPIRATORS
81.000,500
8110,055
8200,100
81.310,655
APPROXIMATE TOTAL CAPITAL COST
81,311,000
(DCC-GWZB)
-------
TABLE A-4
OPEIATION AND MAINTENANCE COST ESTIMATE
FUHOIZEO CMKW KD
QU COMPONENT
COST CCPWITS
SUBSURFACE DRAINS:
OPERAT t MINT
UTILITIES
UELL NONITORINC:
SAMPLING t ANALYSIS
RECHARGE TRENCHING (IN-SITU SOIL "USN
CHEMICALS
UTILITIES
LABOR AND ADMINISTRATION
FLUIDIZEO BED REACTOR STSTEM:
UTILITIES
CHEMICALS
MAKEUP CARBON
ANALT PLANT MONITOR
LABOR * MAINT
TOTAL ANNUAL OlM COSTS
(ApproiiMtt V«l>»>
$15,000
$1.000
SV.OOO 9 *LL$, AMNUAtlT
IMG):
$70,000
ss.ooo
$50,000
$20,000
$15,000
2000
$12,000
$125,000
$324,000
$324,000 FOR TEARS 1 TO 30
(OM-CU2I)
-------
TABLE A-5
BASELINE CAPITAL COSTS
ACTIVATED CARBON
COST COMPONENT
QUANTITY
L11T
UNIT COST
TOTAL COST
COMMENTS
SITE PREPARATION
UEIL REPLACEMENT
SUBSURFACE DRAIN SYSTEM:
DRAINS INSTALL
PUMPS
SUMP INSTALC
PIPING
RECHARGE TRENCHING (IN-SITU
SHALLOW TRENCH INSTALL
INJECTION PUMPS
PIPING
ELECT I INSTRUM
INJECTION TANK
CHEMICAL FEED SYSTEM
HANDLING OF EXCAVATED SOILS
EXCAVATE
ON-SITE HAULING
GROUNDWATE* TREATMENT PLANT
SOIL FILL
SURVEYING
TREATMENT SYSTEM:
OFFICE/LAI
OIL/WATER SEP
CARB ADSORP UNIT
INIT CARB FILL
PIPING/PUMPS
ELECTR I INSTRUM
ANCIL EOUIPMT
OTHER PROC TANKS
HEALTH I SAFETY
DIRECT CAPITAL COST
1 LP SUM
9 WELLS
2100 IF
20 PUMPS
20 SUMPS
1 LP SUN
SOIL FLUSHING):
1500 LF
2 PUMPS
1 LP SUM
1 LP SUN
1 LP SUM
\ LP SUM
is.ooo
$5,000
S50
S3.000
BJ.OOO
•8,000
S25
•3.500
135,000
•20,000
110,000
S5.000
•5,000
•45,000 1 REPLACEMENT PER 30 YEARS
•105,000
•60.000
•60.000
18,000 /
BASED UPON A 10.000 GAL/DAY
•37,500 INJECTION RATE
•7,000
135,000
120,000
•10,000
15,000
FROM TRENCH EXCAVATION:
2000 CY
2000 CY
*15
S3. 00
130,000
16,000 HAULED OH SITE TO THE GRAVEL
PITS; TREATED VIA GR WATER
- PRELIMINARY EARTHWORK:
4000 CY
1 LP SUM
1 LP SUM
1 LP SUM
1 LP SUM
5000 LBS
1 LP SUM
1 LP SUM
1 LP SUM
1 LP SUM
24 WEEKS
•16
SS.OOO
S35.000
116,000
140,000
11
147.000
185,000
181,000
145.000
14,000
•64.000
•5,000
135,000
•16,000
•40,000
•5,000
•47,000
•85,000
181,000
145,000
•96.000 Nil OFFICER DURING EXCAVATION;
H*u AMD RESHRATORS
»952,SOO~
ENGINEERING I DESIGN (11t)
CONTINGENCY (20X)
•104,775
•190,500
TO'AL CAPITAL COST
11,247.775
COST
-------
TABLE A-6
OPERATION ANO MAINTENANCE COST ESI I HATE
ACTIVATED CAIHM
QM COMPONENT ANNUAL COST
SUBSURFACE DRAINS:
OPERAT I NAINT 815,000
UTILITIES S1.000
UELL MONITORING:
SAMPLING I ANALYSIS S9.000 9 UELLS. AMUAU.T
IECHAIGE TUNCHING (IH-SITU SOIL FLUSHUG):
CHEMICALS S70.000
UTILITIES SS.OOO
LAM* ANO ADMINISTRATION SSO.OOO
CARBON ADSORPTION UNIT:
UTILITIES SS.OOO
CHEMICALS S7.000
ANALT PLANT MONITOR S1Z.OOO
VIRGIN CARtOH S3,000
CARHN DISPOSAL S9.000
LABOR t MAINT SI25,000
TOTAL ANNUAL OIM COSTS S311.000
(ApproxiMt* V«lut) »311,000 FOR TCAtS 1 TO 30
(OM-GU2A)
-------
TABLE A-7
OPERATION AND MAINTENANCE COST ESTIMATE
OH) COMPONENT
ANNUAL COST
COMMENTS
FENCE:
PERIODIC INSPECTIONS
REPAIR
U.SOO 4 INSPECT! 8 S1200 EACH
StOO REPLACE IX Of FEMCE/TEM
TOTAL ANNUAL QIM COSTS
15.200
(OM-SL2)
(AppreziMt* Vtluc)
SS.200 K» TEMS 1 TO SO
-------
SUMMARY OF REMEDIAL ACTION ESTIMATED COSTS
CAPITAL COST
ACTIVITY BASELINE
Buyout of the Carver Terrace
subdivision $ 5,000,000
Demolition of the hones and the
removal and disposal of the debris 960,000
Mechanical Soil Washing 2,021,000
Groundwater treatment utilizing /
fluidized carbon bed 1,311,000
(Groundwater treatment utilizing
activated carbon) '(1,248,000)
Estimated Total $ 9,292,000
($ 9,229,000)
The Operation and Maintenance (O&M) costs associated with the
inspecting and repairing the fence on the sand and gravel pit area on
a yearly basis will cost $5,200 (Table A-7). The O&M costs
associated with the fluidized carbon bed and activated carbon are
presented on Tables A-4 to A-6. These tables indicate that the
annual costs for operating a fluidized carbon bed is approximately
$324,000 and for an activated carbon system is approximately
$311,000. Using these annual O&M costs and the capital costs,v the
30-year present worth costs associated with maintaining the fence* an^*
remediating the contaminated groundwater for a 30 year treatmen
duration are:
30-YEAR PRESENT WORTH COST
ACTIVITY BASELINE
Buyout of the Carver Terrace
subdivision $ 5,000,000
Demolition of the homes and the
removal and disposal of the debris 960,000
Mechanical Soil Washing 2,070,000
Groundwater treatment utilizing
fluidized carbon bed _ 4,365,000
(Groundwater treatment utilizing
activated carbon) (4,179,500)
Estimated Total $12,395,000
($12,209,500)
Included in the estimated cost for Mechanical Soil Washing.
-------
ATTACHMENT 3 - STATE OF TEXAS CONCURRENCE LETTER
-------
joha IUU, Chairman
1. J. Wyaae, ffl, Commissioner
PUD Iced, Commissioner
TEXAS WATER COMMISSION
JHAWumrirniwnwGA
December 13, 1991
Mr. Myron 0. Knudson, P.E., Director
Hazardous Waste Management Division
U. S. Bnvironaental Protection Agency
Region 6
1445 Rosa Avenue, Suite 1200
Dallas, Texas 75202-2733
Rs: Koppers Texarkana Super fund site
Draft Amended Record of Decision
Dear Mr. Knudson:
we have reviewed and have no objection to the third draft of the
amended record of decision (ROD) proposed for the Hoppers Texarkana
Superfund Site. This amended ROD would supplement the existing
1988 ROD by authorizing the buyout of the Carver Terrace portion of
the site, providing relocation assistance to the affected
residents, reclassifying the purchased residential area to non-
residential use, and affirming the action level of 100 parts per
million total carcinogenic polynuclear aromatic hydrocarbons
(PAHs) . These actions are also dependent upon satisfactory
resolution of the on-going negotiations between the TWC and EPA
pertaining to the Superfund state Contract (SSC) . The SSC will
provide the State's assurances to match ten percent of the buyout
costs and to take title to the Carver Terrace properties once the
remedial actions described in the amended and existing RODs are
complete.
Sincerely,
Alien Beinke
Executive Director
P.O.Box 13087 • 1700 North Congress Avenue • Austin. Texas 78711 -3087 • 512/463*7830
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