Is
United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R06-88/023
September 1988
EPA Superfund
Record of Decision:
Koppers Texarkana, TXULA1TEXAS
IftRY
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REPORT DOCUMENTATION ^ REPORT NO. z.
PAGE 2PA/ROD/R05-88/023 i
4. Title and Subtitle
SJP^RFJND RSCORJ OF DECISION
Xoppers Texarkana, TX
ea^First Remedial Action
^•*uthor(»)
^^
3. Recipient's Accession No.
5. Report Date
09/23/33
6.
8. Performing Organization Rept. No
9. Performing Organization Name and Address
10. Proiect/Task/Work Unit No
11. Contracted or Grant(G) No.
(C)
(G)
12. Sponsoring Organization Name and Address
U.S. Environmental Projection Agency
401 M Streef, S..V.
Wasningfon, D.C. 20460
13. Type of Report & Period Covered
I
800/000
14.
IS. Supplementary Notes
16. Abstract (Limit: 200 words)
i'ne Koppers rexarkana si^e :.s located wifnin fhe Cify of Texarkana, Texas. The site
consisfs of a 34-acre residential area and a 23-acre former sand and gravel operation.
fne sife .is nordered oy fne Texas and Pacific Railroad fo fne norf-h, an unnamed creek fo
fne norfnwesf, .Vagner Creek fo fne souf.nwesf, Jameson Sfreef ho '•ne sou^h, and a
drainage dircn ho '•ne aou^hwes*". Tne entire si^e is wit-hin a 100-year flood plain. The
Koppers Company operated >~ne si*~e as a ^ood preserving facility from 1910 ^o 1961, using
pen*-acnloropnenol (PCP), creosote, and metallic sal^s in hne operation. The facility
onsist-ed of an operations area, a drip Tack/ and *-rea*-ed and uni-rea»-ed wood storage
reas. fne S3>e is currently owned oy Carver Terrace, Inc., which ouili" a subdivision
of 79 single-family nomes on a portion of hne si'-e, and *-ne Kennedy Sand and Gravel
Company, wm.cn mined sand and gravel on i-heir parcel from 1975 *~o 1984. Two o^her
owners of small portions of '•ne si^e are '•ne Moun*" Zion Missionary Bapt-is*- Church and
Jesse and Qt-na Pace. Tne Texas Department" of .Va'-er Resources (TO*VH) oecame aware of rhe
si»-e in 1979 t-nroagn i-ne Eknardt survey. The sand and gravel pi1- was fenced off, and in
19d5 EPA covered 24 residenfi.al lo*~s wit-h soil and sod t-o prot-ec1" t-he residents while
fne RI/FS was conducted by Koppers under an Adminisf rat-ive order on Consenf. The RI
indicated fhaf fhe nignesf concen1- raf ion of sife conf aminan1- s in fne soil were locafed
(See Affacned Sneef )
u
c i*s
Koppers Texarkana, TX
Firsf Remedial Action
Contaminated Media: gw, sediments, soil
Key Contaminanfs: metal (arsenic), organics (PAH, PCD),
b. Identlfiers/Open-Ended Terms
VOCs (benzene, foluene, xylene)
c. COSATI Field/Group
Availability Statement
19. Security Class (This Report)
1 None
I 20. Security Class (This Page)
! None
21. No. of Pages
103
22. Price
(See ANSI-Z39.18)
See Instructions on Reverse
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Department of Commerce
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OPTIONAL FORM 272 BACK
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EPA/ROD/R06-88/023
pppers Texarkana, TX
'irst Remedial Action
16. ABSTRACT (continued)
n*ear the operations and drip track areas of the old wood preserving facility. In
addition, the highest concentrations in the ground water were noted in or near pockets
of non-aqueous phase liquids (NAPLs) also in these site areas. The primary contaminants
of concern affecting the soil, ground water and sediments are VOCs including benzene,
xylenes, and toluene, other organics including PAHs and PCP, and metals including
arsenic.
The selected remedial action for this site includes: excavation of approximately
3,300-19,400 yd3 of soil from residential yards where CPAH levels exceed 100 mg/kg,
with backfilling using clean soil, landscaping disturbed yards, and onsite treatment of
the soil using soil washing with disposal in the Kennedy Sand and Gravel pit or an
offsite hazardous waste disposal facility; temporary relocation of sensitive residents
(if necessary); collection of NAPLs via trenches in the Kennedy Sand and Gravel pit
and/or via a well nest in Carver Terrace and treatment at an onsite waste water
treatment plant using oil/water separation followed by activated carbon or fluidized
carbon bed treatment with recycling or offsite incineration of recovered NAPLs and
reinjection of treated ground water into the aquifer; ground water monitoring;
excavation and treatment of drainage ditch sediments in the soil washing unit; and deed
and access restrictions. The estimated present worth cost for this remedial action is
$6,400,000, which includes annual O&M costs of $300,000.
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DECLARATION FOR THE RECORD OF DECISION
SITE NAME AND LOCATION
Koppers Texarkana site, Texarkana, Texas
STATEMENT OF PURPOSE
This decision document presents the selected remedial action for the Koppers
Texarkana site in accordance with the Comprehensive Environmental Response,
Compensation and Liability Act of 1980, as amended by the Superfund Amend-
ments and Reauthorization Act of 1986; and the National Oil and Hazardous
Substances Pollution Contingency Plan, 40 CFR Part 300, November 20, 1985.
The State of Texas (through the Texas Water Commission) has been provided
an opportunity to comment on the technology and degree of treatment proposed
by the Record of Decision and has no objection to the selected remedy (See
Appendix D).
STATEMENT Of BASIS
This decision is based upon the administrative record for the Koppers
Texarkana site. The attached index identifies the documents which comprise
the administrative record. (See Appendix E).
DESCRIPTION OF THE REMEDY
The selected remedy will treat the health- and environment-threatening
contamination resulting from historical wood preserving operations at the
site. Upon review of the information contained in the administrative record,
EPA has determined that oil/water separation and either carbon adsorption or
fluidized carbon bed treatment of groundwater and mechanical soil washing
of the Carver Terrace contaminated soils best fulfills the statutory selec-
tion criteria. The following is a brief summary of the proposed remedy:
Carver Terrace Soils: The selected remedy requires excavation of yards where
the sum of the carcinogenic polynuclear aromatic hydrocarbons (PAHs) in
soil exceeds 100 ppm. The yards within the general area of contamination
identified during the Remedial Investigation will he sampled during the
Remedial Design. Short-term risks will be controlled by covering excava-
tions at the end of the day with clean soil, suppressing dust, and tempor-
arily relocating sensitive residents if necessary. Excavated yards will be
backfilled with clean soil purchased from outside the site, graded to pre-
vent ponding of rainfall in yards, and covered with sod to prevent erosion
and to replace the grass. In addition, any existing landscaping destroyed
during the excavation will be replaced.
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Excavated soils will be transported to Kennedy Sand & Gravel where a soil
washing unit will he constructed. Cleansed soils will be disposed of in
the gravel pits at Kennedy Sand & Gravel J_f the soils meet the remedial
goal of 100 pom carcinogenic PAHs and also show no continued leaching
potential using the EPA Foxicity Characteristic Leaching Procedure test.
Otherwise, the soils will need to be disposed of at an off-site hazardous
waste facility.
Stratum I Groundwater: The remedy also requires collection and treatment
of non-aqueous pnase liquids (NAPLs) in groundwater in stratum I. Collec-
tion trenches will be installed around and across the Kennedy Sand & Gravel
part of the site. In addition, a well nest and collection station nay need
to he installed in a vacant area in Carver Terrace to the north of West
Third Street to quicken the collection of a pocket of NAPLs located there.
Groundwater collection will continue until the NAPLs have been recovered to
the maximum extent possible. This level will be determined during the
Remedial Action based upon operational experience in using the collection
and treatment system. After this point is reached, the groundwater collec-
tion will cease and the groundwater will be allowed to naturally attenuate
to background levels. Monitoring will be used to ensure that natural
attenuation is continuing.
The groundwater and NAPLs will be treated at an on-site wastewater treatment
plant. Treatment will include oil/water separation followed by either an
activated carbon or fluidized carbon bed system. Any NAPLs collected and
separated from the groundwater will be recycled as creosote or incinerated
off-site. Spent carbon will he regenerated off-site. The water will be
treated to levels equal to the Best Available Treatment requirements for
the Organic Chemical, Plastics, and Synthetic Fibers industry. Cleansed
groundwater will he reinjected into the aquifer along with surfactants to
help recover the NAPLs. Any excess water will either he directly dis-
charged to Wagner Creek or to a local wastewater treatment plant under the
requirements of a pretreatment permit.
Drainage Ditch Sediments: Sediments in the bend of the drainage ditch
which cuts across the old lagoon area within Kennedy Sand & Gravel will be
excavated and used in the pilot testing of the soil washing unit.
Drill Cuttings: The drill cuttings collected during the Remedial Investiga-
tion will be combined with the excavated Carver Terrace Soils, treated in
the mechanical soil washing unit, and disposed of along with the treated
Carver Terrace soils.
Kennedy Sand and Gravel Property: This remedial action is based on site
control , imposition of necessary deed notices, and restriction of access to
this part of the site by use of a fence through the duration of the Remedial
Action.
Stratum II Confined Zone: This zone will be allowed to naturally attenuate
following remediation.The zone will be monitored to ensure that it is
being naturally cleansed.
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Operation and Maintenance: The need for future operation and naintenance
will be minimized since the primary sources of contamination will he removed
tnrough treatment. Site operation and naintenance will include nonitoring
of groundwater wells, anbient air (during remediation only), and Wagner
Creek water. The length of the groundwater and Wagner Creek monitoring
program will continue for at least 30 years unless it can he shown during
the Remedial Action that some shorter length of time is appropriate. This
sampling program will monitor the effectiveness of the selected remedy and
provide the data necessary to trigger future corrective action, if necessary.
Additional site naintenance would include, hut not necessarily he limited
to, inspections of surface vegetation, ensuring proper drainage, proper
operation of any actions such as groundwater treatment which could extend
heyond the time required for the source control remedy, and periodic fence
repair. The details of these activities will he defined in the Operation
and Maintenance Plan of the Remedial Design. The monitoring data will he
evaluated during the Agency's 5-year review, in accordance with SARA Section
121(c), to determine if any corrective action is necessary.
DECLARATION
The selected remedy is protective of human health and the environment,
attains Federal and State requirements that are applicahle or relevant and
appropriate, and is cost-effective. This remedy satisfies the preference
for treatment that reduces toxicity, mohility or volume as a principal
element. Finally, it is determined that this remedy utilizes permanent
solutions and alternative treatment technologies to the maximum extent
practicable.
23, Ml
Dare Robert E. Layton' Jr.
Regional Administrator
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SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
KOPPERS TEXARKANA SITE
TEXARKANA, TEXAS
SEPTEMBER 1988
U. S. ENVIRONMENTAL PROTECTION AGENCY
REGION VI, DALLAS, TEXAS
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TABLE OF CONTENTS
1. SITE LOCATION AND DESCRIPTION 1
2. SITE HISTORY 1
2.1 Previous Site Use 1
2.2 Response and Remedial Activities 4
2.3 Enforcement 4
3. SITE CHARACTERISTICS 6
3.1 Geology and Hydrogeology 6
3.2 Surface and Surficial Soils 8
3 . 3 Groundwater 12
3.4 Surface Water and Sediments 12
3.5 Air 12
4. SITE RISKS 12
4.l Exposure Pathways 17
4.2 Potential Health Risks 18
4.3 Remedial Goals 18
5. COMMUNITY RELATIONS HISTORY 19
6. SCOPE AND ROLE OF ACTION WITHIN SITE STRATEGY 20
7. ALTERNATIVES EVALUATION 20
7.1 Description of Alternatives 20
7.2 Evaluation of Alternatives 24
8. SELECTED REMEDY 30
8.1 Description of the Remedy 30
8.2 Significant Changes from Proposed Plan 32
8.3 Statuatory Determinations 33
8.4 Future Actions 36
APPENDICES
A Responsiveness Summary
B Applicable or Relevant and Appropriate Requirements
C Risk Calculations
D State of Texas Concurrence
E Index to the Administrative Record
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LIST OF FIGURES
Page
1 Location of Koppers Texarkana Site within Texarkana
7.5 Minute Quadrangle 2
2 Koppers Texarkana Site Map 3
3 Old Plant Area 5
4 Generalized Stratigraphic Column for the Koppers
Texarkana Site 7
5 Isoconcentration Map of Total PAHs in Surface
Soils at the Koppers Texarkana Site 10
6 Isoconcentration Map of Total PAHs in Unsaturated
Subsurface Soils at the Koppers Texarkana Site 11
7 Lateral Extent of Impacted Groundwater in the
Shallow Unconfined Aquifer 14
8 Lateral Extent of Impacted Groundwater in the
Leaky Confining Zone 15
LIST OF TABLES
Page
1 Surface Soil Concentrations 9
2 Groundwater Concentrations 13
3 Surface Water and Sediment Concentrations 16
4 Comparison of Remedial Alternatives 25
11
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1. SITE LOCATION AND DESCRIPTION
The Koppers Texarkana site is located within Texarkana, Texas,
approximately one mile west of downtown Texarkana (Figure 1).
The site is bordered by the Texas and Pacific Railroad to the
north, an unnamed creek to the northwest, Wagner Creek to the
southwest, Jameson Street to the south, and a drainage ditch to
the southwest. The site describes a trapezoid with a length of
approximately 2800 feet, a width ranging from 700 to 1,500 feet,
and an area of 62 acres.
The site consists of a residential area and a former sand and
gravel operation. The residential area, covering 34 acres of the
northern part of the site, consists of a subdivision, a church,
and another house. The subdivision, Carver Terrace, includes 79
single family houses. The Mt. Zion Missionary Baptist church is
located in the southeast corner of Carver Terrace. The other
house is located just to the east of the church. The remainder
of the site is a former sand and gravel mine owned by Kennedy
Sand and Gravel and covers 28 acres of the southern part of the
site (Figure 2).
The site is generally flat with a few topographical depressions
near water bodies. These are Wagner Creek, a drainage ditch on
the southeastern side and two large gravel pits in the sand and
gravel mine. The entire site is also within the 100 year flood
plain. It is drained by the drainage ditch, Wagner Creek, and
the tributary to Wagner Creek which flank the site on the east
and west sides. The drainage ditch empties into Wagner Creek
approximately 500 feet south of the site. Wagner Creek dis-
charges into Days Creek, a tributary of the Sulphur River. Days
Creek is currently classified in the Texas water quality stand-
ards as an intermediate aquatic habitat.
2. SITE HISTORY
2.1 PREVIOUS SITE USE
The Koppers Texarkana site was used as a wood preserving facility
from 1910 to 1961. The wood preserving facility consisted of an
operations area, a drip track, and treated and untreated wood
storage areas. The operations area included wood treating cylin-
ders, chemical storage tanks, and a wastewater lagoon; this area
was located in the east-central portion of the site. Pentachlor-
ophenol (PCP), creosote, and metallic salts were used in the
operation. The drip track ran diagonally from the operations
area to the northwest, and ended at the northern boundary of the
site. Treated wood was stored in the western and southern areas
of the site; untreated wood was stored in the northeastern area.
In 1961, the Koppers Company ceased operation of the facility,
removed the surface structures, and sold the site to two people,
The site was later sold to a succession of owners until Carver
Terrace, Inc., purchased most of the site in 1964. Carver Ter-
race, Inc., built 79 single family houses in the northern part of
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.-.., .. .
/••fjjH^—i.V -
KCPPERS TEXARKANA
TexarRa-saj
CONTOUR INTERVAL 10 FE!
NATIONAL GEODETIC VERTICAL OATuM OF 1929
Figure 1
Location of Koppars Texarkana Site within Texcrfccna 7,5
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? • Koppers TexarKana Site Map
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the site, but did not complete the development because of flood-
ing problems in the area.
Carver Terrace, Inc., later sold the southern part of the site to
Kennedy Sand and Gravel in 1975. This company mined sand and
gravel until the Texas Department of Water Resources (TDWR)
ordered the company in 1984 to cease operations. Carver Terrace,
Inc., also sold a 0.5 acre portion which is now owned by the Mt.
Zion Missionary Baptist Church. The Koppers Company sold a small
portion of the site which, through a succession of owners, is now
owned by Jesse and Otha Pace (the house to the east of the
church). Figure 3 shows current and historical site features.
2.2 RESPONSE AND REMEDIAL ACTIVITIES
In 1979, the TDWR became aware of this site through the Ekhardt
Survey. The TDWR and the U. S. Environmental Protection Agency
(EPA) sampled the site in 1980 and 1981, respectively. Based on
this information, TDWR referred the site to EPA for inclusion on
the National Priorities List (NPL). EPA proposed the site to be
added to the NPL in October 1984; the site was formally promul-
gated in June 1986.
EPA began the preliminary site investigations in October 1984 by
collecting four water and seven soil samples. EPA also collected
soil samples from 44 residential yards and several drinking water
taps in 1985. From this data, EPA determined that a fence needed
to be placed around Kennedy Sand & Gravel, arid that 24 residen-
tial lots needed to be covered with soil and sod. These actions
were taken in 1985 to temporarily protect the residents while EPA
conducted a Remedial Investigation and Feasibility Study (RI/FS).
The Remedial Investigation (RI) was completed in April of 1988
with the submittal of the report. The RI included investigations
into contamination in soils, groundwater, surface water and sedi-
ments, and air. The Feasibility Study (FS) was completed in June
of 1988. The FS evaluated several methods for remediating the
site problems including containment and treatment technologies.
2.3 ENFORCEMENT
EPA identified ten potentially responsible parties (PRPs) in the
initial stages of the RI. EPA issued Administrative Orders on
Consent to the Koppers Company and another PRP in 1985 to com-
plete the response activities discussed above. EPA also issued
an Administrative Order on Consent to the Koppers Company in 1985
to conduct a RI/FS.
EPA mailed copies of the proposed plan of action for this site to
the PRPs on July 1, 1988. EPA will continue its enforcement
activities by sending a Special Notice letter to the PRPs before
the initiation of the remedial design. Should the PRPs decline
to conduct future remedial activities, EPA will either pursue
litigation to obtain remediation by PRPs or will provide funding
for these activities and later will seek cost recovery for all
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I
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EPA-funded response actions from the PRPs.
3. SITE CHARACTERISTICS
The RI characterized local geology and hydrogeology and investi-
gated four different types of environmental media at the Koppers
Texarkana site: soils, groundwater, surface water and sediments,
and air. The samples collected during this period were analyzed
for substances characteristic of wood preserving sites: polynuc-
lear aromatic hydrocarbons (PAHs), pentachlorophenol (PCP), some
dioxin and furan isomers, volatiles (benzene, toluene, and
xylenes) and metals (arsenic, chromium, copper and zinc). The
analytical results from the RI are described in the report dated
April 12, 1988. A brief summary is presented below.
3.1 GEOLOGY AND HYDROGEOLOGY
The Koppers Texarkana site is in the Gulf Coastal Plain region.
This region is characterized by thick deposits of unconsolidated
sands, silts, and clays from riverine and marine sediments (see
Figure 4). The depositional settings of the sediments range from
braided streams to delta complexes to deep sea marine sediments.
The geology of the upper 103 feet consists of five distinct layers:
Average
Stratum Depth (ft) Description
I 0-24 Coarse sand and gravel graded with fine
sand and silt (Quaternary Alluvium)
II 24-50 Roughly 50% clay interlaid with 50% sand
and silty sand (Wilcox Group)
III 50-75 Mostly sand and silty sand interlaid with
clay (Wilcox Group)
IV 75-85 Two lignite beds divided by clay and sand
(Wilcox Group)
V 85-103 Thick clay (Wilcox Group)
Stratum I is the uppermost water bearing unit at this site. This
unit is not used now as a water source because the aquifer yield
is low as shown by a pump test during the Remedial Investigation.
Stratum III is another water bearing unit and has been used as a
water supply by homeowners. The Remedial Investigation identi-
fied three wells located off-site which are screened in this
stratum; these wells are up-gradient of the site.
The potentiometric surfaces developed during the Remedial Inves-
tigation show that the groundwater flow is generally toward the
south which is consistent with the regional groundwater flow.
Groundwater in the Stratum I flows generally to the south at an
average velocity of approximately 7 feet/year. The gravel pits
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GEOLOGIC UNIT
QUATERNARY
FLUVIATILE
TERRACE DEPOSITS
and
FILL
Thickness
10 to 21 ft
UNCONFORMITY
TERTIARY
WILCOX GROUP
(Eocent)
Thickness 95 ft
to undetermined
AQUIFER
Shallo*
Unconfirmed
Aquifer
Leaky
Confining Zone
Semi-confined
Aquifer
SAND and GRAVEL
CLAY
silt and sand in matrix,
beds, or laminations
LIGNITE
figure 4: Generalized Stratigraphic
Column for the Koppers Texarkana Site
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in the southern part of the site collect rainfall which, through
surface percolation, creates a groundwater mound causing radial
flow in this area. Wagner Creek and the southeastern drainage
ditch intercepts any radial flow.
Groundwater in Stratum III also flows generally to the south
although the flow is more to the southwest. The average velocity
in this stratum is also approximately 7 feet/year. Well observa-
tions during the Remedial Investigation show that the gravel pits
act as a source to this aquifer, but do not significantly affect
the direction of water flow. Paired well observations show that
groundwater migrates upward from Stratum III to I.
The soils within Stratum II consist of proportional amounts of
silty sand and sand with clay. These soils do not characterize
either an aquifer or aquitard. Instead, these act as a leaky
confining zone which allows vertical and horizontal migration of
grcundwater, but only slower than those in the strata above and
below. The vertical velocity averages 5x10 cm/sec.
3.2 SURFACE AND SURFICIAL SOILS
Surface and surficial soils comprise the top five feet in soil
stratum I; surface soils are in the upper foot. Table 1 shows
the maximum concentrations of site contaminants in surface and
surficial soils.
Site contaminants were observed in surface and surficial soils
over nost of the residential area in the northern half of the
site. The contaminants found most often were PAHs; Figures 5 and
6 show their distribution. Approximately 12 acres of the site
have PAHs exceeding 100 ppm, and 2 acres of the site have PAHs
exceeding 1000 ppm. Other site contaminants (PCP and metals)
were also found but only in a few small areas.
Higher concentrations of the PAHs in surface soils are associated
with the operations and drip track areas of the old wood preserv-
ing facility. The contaminants in these areas have migrated
downwards (Figure 6). Contaminants in these areas are not con-
tinuing to migrate as shown by the baseline treatability tests
conducted during the Feasibility Study. Lower concentrations are
more widespread; these appear to be caused by the grading of the
site during development as a residential subdivision.
The site investigations did not find any abandoned tanks,
vessels, or sludges. According to workers from the 'facility,
these were removed when the facility closed in 1961.
In addition, there are three metal containers on the site which
hold drill cuttings from RI activities. These containers hold
about 160 cubic yards of soils which also need remediation.
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TABLE 1
SURFACE SOIL CONCENTRATIONS
( 1 )
C o n t a m i n a n t
Arsenic
Ch r omiurn
Copper
Lead
Zinc
Pentachlorophenol 16
TCDD Equivalents (ug/kg) 0.77
Acenaphthyiene
Acenaphthene
Anthracene
8enzo(a)anthracene
8 e n z o (a )py r ene
Senzo(D&k)fluoranthene
8 e n z o ( g , h ,i) p y r ene
Chrysene
2iDenzo(a,h)anthracene
Fluoranthene
F ', u o r e n e
I 2 e n o (1,2,3-cd)pyrene
2-Hethytnaphthalene
N a ph t h a Iene
Phenantnrene
P y r ene
Total = A Hs
Carcinogenic PAHs
Maximum
Carver
Terrace
53
58
101
298
3370
Concentration
Kennedy
SandiGravel
15
12
10
na(3>
35
Health
Based
Levels
2
1,500
111,000
4, 200
633 , 000
(2)
1 ,
1 ,
1
1 ,
240.
2,
1 ,
1 3 ,
2 ,
995
1 00
235
395
480
900
1 20
250
1 0
950
095
130
100
000
010
275
166(4)
201
nd
5
nd
nd
10
220
nd
5
nd
29
no
1 9
nd
nd
nd
69
291
221
0 .8
(3)
83,000
1 . 0
3 .
units of mg/kg unless otherwise noted; o a s e u on 156 samples
based on risk calculations for residential exposure
equal to the reference dose, 10 c a n c e r risit, or
(3)
the ATSOR action level
na = not analyzed; nd - not detected
excludes maximum naphthalene value which
characterizes only a small spill area
-------
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-------
-,*- •
I
TOTAL PAM .
, ISOCONCgNTRATION LINES
i 10 - 10 opm
>— *JOO — 100 ocm
•"•—""• 1000 ppm
SITE BOUNDARY;
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TOTAL PAH CONCENTRA'! N
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sf-1 •-
-------
3.3 GROUNDWATER
Table 2 shows the maximum concentrations of site contaminants
found in groundwater. Site contaminants were observed over the
southern two-thirds of the northern half of the site with only a
little off-site migration (Figure 7) . As much as 45 million gal-
lons of groundwater contain these contaminants. As with the
surface and surficial soils, PAHs were the contaminants found
most often although volatile compounds such as benzene and tol-
uene were also seen. The highest concentrations were seen in or
near pockets of non-aqueous liquids (NAPLs) ; these were found
under the operations and drip track areas of the old wood preser-
ving facility. PCP was found in only the old lagoon area.
Metals were also found over the site but only at levels below
drinking water levels.
Most of the contaminants are located in the upper aquifer (5-24
feet) . The leaky confining zone below this aquifer is retarding
vertical migration, but does not completely prevent vertical
migration to the lower aquifer. Some wells and deep borings show
partial penetration of organics into the leaky confining zone
(Figure 8) .
The upper aquifer also serves as source of contamination to sur-
face waters. There are observable seeps of NAPLs from the aqui-
fer into both Wagner Creek and the open gravel pits within Ken-
nedy Sand & Gravel.
3.4 SURFACE WATER AND SEDIMENTS
Table 3 shows the maximum concentrations of site contaminants in
surface water and sediments. As stated previously, these media
receive contaminants by migration from the upper aquifer. Water
samples showed no detectable concentrations of site contaminants
except for those direct samples of the seeps.
Impacts were more obs-ervable in the sediments. PAHs were seen in
Wagner Creek sediments just below the location of the seep and in
the on-site drainage ditch which cuts across the area of the old
wastewater lagoon.
3.5 AIR
On-site air samples were collected during the RI . Two phenolic
compounds were seen, but upwind samples showed more of these than
did the downwind samples. Therefore, the presence of these com-
pounds is related to either background air quality in Texarkana
or interferences in the test procedures.
4. SITE RISKS
The potential risks from contaminated soil, groundwater, sedi-
ment, and surface water were calculated based on present site
and plausible future development conditions. Both carcinogenic
and non-carcinogenic risks were calculated. The carcinogenic
12
-------
TABLE 2
GROUNDUATER CONCENTRATIONS*
Contaminant
N a x i mum
Coneentrat ion
federa I
and State
Standards
(2)
BAT
Monthly
0 i scharge
L,mitS(3)
Arsenic
C h r OITI i urn
Copper
Lead
Zinc
430
270
149
67
18, 000
50
50
1 , 000
50
5, 000
1,110
1 , 450
320
1 ,050
Benzene
Ethylbenzene
Toluene
X y I enes
Pentachlorophenol
700
2,100
1 ,900
2,900
2, 200
5
680
2,000
440
220
57
142
28
AcenaphthyIene 1,000
Acenaphthene 1,500,000
Anthracene 580
Benzo(a)anthracene 6,100
Benzo(a)pyrene
Ben:o(b&k)fluoranthene
B en z o(g,h , i ) py rene
Chrysene
Dibenzo(a,h)anthracene
Fluoranthene 1
FIuo r ene 1
1 deno( 1 ,2,3-cd)pyrene
2•He thyInaph tha t ene 1
Naphthalene 5
Phenanthrene 3
Pyrene 1,300,000
1 ,900
3, 700
nd
3, 700
nd
500,000
200,000
nd
100,000
500, 000
600, 000
(4)
1 9
1 9
1 9
1 9
20
1 9
1 9
22
1 9
1 9
1 9
20
Total PAHs
Carcinogenic PAHs
15.700 ,000
11 .700
0.003
(1 )
C 2 )
(3)
(4 )
units of micrograms per liter; based on 37 wells
final and proposed primary and secondary drinking water
standards except for 10 risk level for carcinogenic PAHs
based on organic chemical, plastics, and synthetic fioers
effluent guidelines for physical/chemical treatment
nd = not detected
NOTE: All PAHs exceed the solubility constraint;
data shows presence of non-aqueous phase i i q _ •. d
-------
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-------
TABLE 3
SURFACE WATER, SEDIMENT, AND SEEP CONCENTRATIONS'
C o n t a m i narit
Arsenic
Ch r oni i um
Copper
Lead
Zinc
Benzene
Ethyl benzene
Toluene
X yIene s
Pentachlorophenol
Ac enaph t h yIene
A c enaph t hene
Anthracene
B enz o(a)an t h r ac ene
B enzo
-------
risks are theoretical quantifications of the excess lifetime
cancer risk, that is, the incremental probability of getting
cancer compared to the probability if no exposure occurred. For
example, a 10~6 excess extra cancer risk represents an exposure
that could result in one extra cancer case per million people
exposed. Non-carcinogenic risks are determined by comparing
potential exposures of people to contaminant specific reference
doses. The reference dose is an estimate of a level that would
not be expected to cause adverse effects in sensitive people.
4.1 EXPOSURE PATHWAYS
The principal exposure pathways through which humans might poten-
tially become exposed to contaminants at this site are defined in
chapter 2 of the FS report and are summarized below:
o inadvertent ingestion, dust inhalation, and direct contact
with surficial soils by utility workers in trenches;
o inadvertent ingestion and direct contact with surface soils
by children;
o inadvertent ingestion and direct contact with surface
sediments and seeps by children;
o ingestion of deeper groundwater if water supply wells are
ever installed on-site.
People can become exposed to contaminants in Carver Terrace
(soils), Wagner Creek (water, sediments, and seeps), and Kennedy
Sand & Gravel (soils and sediments) if they trespass on that
property. People also could become exposed on a more frequent
basis to contaminants in Kennedy Sand & Gravel if that area was
ever developed for residential purposes. This area has not been
developed because it is within the 100 year flood plain, and a
local ordinance places several restrictions upon development of
floodplains.
The groundwater exposure pathway represents only a future sce-
nario. There are no water supply wells within the area of
groundwater contamination. The on-site residents are all served
by the city water supply which originates from a reservoir
located more than 10 miles off-site. There are three privately
owned residential wells located off-site within one mile which
are used to augment the city water service. These wells are
located up-gradient of the site and are screened in a deeper
aquifer (stratum III) . Also, the pump test during the RI showed
that the upper aquifer has insufficient yield (<0.5 gpm) to be
usable as a water supply. However, the deeper aquifer does pro-
vide sufficient yield to supply a private well. Therefore, the
future groundwater pathway can become complete if migration of
dense NAPLs continues and if an on-site well is installed.
17
-------
4.2 POTENTIAL HEALTH RISKS
The exposure to site contaminants is of concern because some of
the chemicals are potential carcinogens (ie. benzene, arsenic,
and benzo(a)pyrene) or are otherwise toxic to humans (xylenes,
toluene, and PCP). Some of these exceed health based reference
doses, cancer risks, and drinking water standards (Tables 1, 2,
and 3).
EPA assessed the above pathways and contaminant concentrations
with relation to risks to human health if no remedial action is
taken. These risks are reported in the FS report and also in
Appendix C of this document. They are also summarized below as
the aggregate risk to each receptor group from all site contami-
nants and pathways. These risks are upper bound estimates of
potential effects on human health; the true risks are most likely
lower and may be zero.
Receptor Group
Carver Terrace Residents
Utility Workers
Future Groundwater Users
Noncarcinogenic
Hazard Index
(Target = 1)
Average. Maximum
Excess Lifetime
Risk of Cancer
Average Maximum
0.01
0.08
<0.01
14.4
2X10
-5
6x10
1x10
3x10
-4
-7
-2
4.3 REMEDIAL GOALS
EPA concluded from the risk assessment that potential public
health hazards exceeded EPA's maximum level for leaving contami-
nation at a site. Using the exposure scenario which considers
Kennedy Sand & Gravel in its current use as a secured commercial
facility, target remedial levels for selected chemicals were
developed:
Contaminant
Carcinogenic PAHs
Free Phase Creosote
Environmental
Medium
Carver Terrace
soils
Groundwater
Remedial Level
100 ppm
no defection
The remedial goal for Carver Terrace soil was selected to prevent
against an additional risk of cancer from exposure to soils of
greater than 3x10 and also ensure against any non-carcinogenic
hazards. The cancer risk level was selected as appropriate
because the cancer potencies for many of the carcinogenic PAHs is
overstated in the risk assessment. The actual potencies can be
lower by 10 to 100 times; this would reduce the estimated cancer
risk by 10 times at a minimum.
18
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The remedial goal for groundwater was selected to prevent migra-
tion of non-aqueous phase liquids (NAPLs) consisting of free
phase creosote. As previously stated, the vertical groundwater
migration is upward; most site contaminants will not migrate to
lower aquifers unless those contaminants are heavier than water.
The dense NAPLs can migrate; therefore, they must be removed. In
addition, light NAPLs do migrate into Wagner Creek, and they must
also be removed from the groundwater. After the NAPLs are
removed, infiltration and migration will cleanse the aquifer of
residual aqueous phase contaminants.
From the Remedial Investigation results, approximately 2 to 12
acres of soil above 1 feet in depth and 45 million gallons of
groundwater exceed these levels. Figures 5 through 8 show the
areas of surficial soil and groundwater where remedial levels are
exceeded.
5. COMMUNITY RELATIONS HISTORY
In October 1984, EPA proposed to add the Koppers Texarkana Street
site to the National Priorities List. EPA held an initial commu-
nity meeting on October 18, 1984, to discuss the reasons for
listing the site on the National Priorities List (NPL). On Janu-
ary 3, 1985, EPA held a second meeting to describe the initial
response actions to be taken at the site. EPA held a third meet-
ing on May 7, 1985, to announce that the Koppers Company would
conduct the site investigation under EPA's supervision; EPA also
presented the schedule for this investigation. Fact sheets were
periodically mailed to local residents and interested parties to
describe the field activities.
EPA issued a press release on June 23, 1988, announcing the con-
clusion of the Remedial Investigation and Feasibility Study, the
availability of reports on those studies, the availability of the
Administrative Record, and EPA's preferred alternative. The
press release also informed the public that the comment period on
the reports, Administrative Record, and preferred alternative
would begin on July 1, 1988, and end on July 30, 1988. The press
release also invited all interested citizens to an open house on
June 28, 1988.
EPA prepared a fact sheet which described remedial alternatives
along with the EPA preferred remedy; this was mailed to the
interested and on-site citizens on June 24, 1988. The fact sheet
gave a brief site history, described the Superfund process and
remedial alternatives, provided details on the public comment
period and the public meeting to be held on July 20, 1988.
On June 27-28, 1988, EPA conducted on-site interviews with the
homeowners in the Carver Terrace subdivision and gave each resi-
dent a copy of the fact sheet. EPA met with the Mayor and Mayor
Pro Tern of Texarkana on June 28, 1988, and also conducted an open
house at the Southwest Center, 3222 West 7th Street, in Texarkana
to present the alternatives to the homeowners in Carver Terrace
19
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and answer their questions.
On July 20, 1988, at 7:00 pm, EPA conducted a public meeting at
the Southwest C&nter in Texarkana to brief the homeowners and
citizens on the study findings, reviewed the alternatives consid-
ered, presented EPA's preferred remedy, answered questions and
received comments. Seventy people attended this meeting.
6. SCOPE AND ROLE OF ACTION WITHIN SITE STRATEGY
Except for the previously completed response actions, the reme-
dial activities at the Koppers Texarkana site has not been separ-
ated into operable units. Therefore, the site problems, remedial
alternatives, and selected remedy described in this Record of
Decision consider all contaminated media identified at the site.
7. ALTERNATIVE EVALUATION
In confonnance with the National Contingency Plan (NCP), EPA
screened initial remedial approaches to determine which might be
appropriate for this site. The Feasibility Study describes the
details of this evaluation. From these possible remedies, seven
alternatives were chosen for detailed evaluation. One other
alternative, No Action, was also evaluated to comply with the
requirements of the NCP.
7.1 DESCRIPTION OF ALTERNATIVES
The seven alternatives described below differ only in the method
by which surface and surficial soils in Carver Terrace are reme-
diated. There are several elements common to all alternatives
which include:
o Restricting access and land use at Kennedy Sand & Gravel
through the duration of the Remedial Action;
o Monitoring Wagner Creek upstream and downstream;
o Monitoring groundwater at nine existing wells; and
o Disposing drill cuttings from the Remedial Investigation
field work.
The first three common elements require long-term maintenance at
the site to replace sections of the fence and monitoring.
In addition, all alternatives except the No Action alternative
collect groundwater contaminants in a series of trenches
installed at Kennedy Sand & Gravel to one foot below the depth of
the NAPLs. The trenches will surround the site boundaries at the
points where groundwater migrates off-site. In addition,
trenches will be installed throughout Kennedy Sand & Gravel to
shorten the time for groundwater recovery. If necessary, a well
nest may be installed in a vacant area in Carver Terrace north c
West Third Street to collect contaminated groundwater there.
20
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The extracted groundwater will be treated by an oil-water separ-
ator to remove the NAPLs followed by either an activated carbon
adsorption system or a fluidized carbon bed reactor to remove
trace organics. Both treatment methods showed similar perform-
ance during the treatability tests conducted as part of the Feas-
ibility Study. The selection of which treatment method to use
constitutes one option under each alternative. Part of the
treated groundwater will then be re-injected with surfactants
into the formation to aid groundwater recovery; the remaining
treated groundwater will be disposed of directly into Wagner
Creek to the west of the site or into a local wastewater treat-
ment plant. The selection of the disposal point provides a
second option under each alternative. The recovered NAPLs will
be sent off-site to be recycled or incinerated; the spent acti-
vated carbon will be regenerated off-site.
Groundwater collection and treatment will continue until the
NAPLs are recovered. During this period, several operational and
maintenance requirements are required including maintenance of
pumps and treatment equipment, replacement and regeneration of
activated carbon, and utility costs. The time for this cannot be
estimated because there is no present model to estimate migration
of NAPLs in groundwater. Therefore, for costing purposes, a 30
year duration was used. Under this assumption, the approximate
costs for groundwater recovery and treatment range from
$1,248,000 to $1,311,000 capital; $311,000 to $324,000 annual
operation and maintenance (0/M); and $4,180,000 to $4,365,000
present worth.
Alternative 1: No Action
Besides the common elements for remediation, this alternative
includes long-term soil and groundwater monitoring and deed
notices. Approximately 22 lots in the most contaminated area
will be monitored each year to determine if the soil/sod barrier
in the lots is deteriorating and if PAHs are naturally degrading
at the rate expected. In addition, the deeds for the residential
properties will be amended to notice the presence of hazardous
substances so that future property owners will not inadvertently
contact the contaminated soils. Finally, the drill cuttings will
be disposed of off-site in a hazardous waste landfill.
The long-term monitoring under this alternative will continue
until the soil contaminants degrade below the health-based reme-
dial level. Therefore, this alternative has no definite end
point. For costing purposes, a 30 year duration was used. Under
this assumption, the approximate costs for this action are
$72,000 capital, $23,000 annual 0/M, and $289,000 present worth.
Alternative 2: Capping
This remedy includes all the common elements and groundwater
treatment along with installation of a cap over the areas of
Carver Terrace which exceed the remedial goals. The cap will
21
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prevent access to contaminated soils by placing a physical bar-
rier between residents and the soils. It will not be designed to
prevent continued leaching from soils into groundwater because
site data showed little potential for continued leaching. The
cap will be compatible with existing land use: soil and sod will
be used inside residential lots, asphalt will be used in parking
areas. It will be inspected annually and repaired if necessary.
Finally, the drill cuttings will be disposed of off-site in a
hazardous waste landfill.
This alternative, exclusive of the groundwater action, will take
approximately two years to complete. The approximate costs for
this remedy, including groundwater costs, range from $2,007,000
to $2,070,000 capital; $316,000 to $329,000 annual 0/M; and
$4,988,000 to $5,173,000 present worth.
Alternative 3: In Situ Biological Treatment
This remedy represents treatment of contaminated surface soils in
Carver Terrace by accelerating the natural biological degradation
of the organic contaminants. The soils will be periodically
aerated, and lime, and fertilizers will be added. An automated
water sprinkler system will be installed to provide water on a
scheduled basis. This approach enhances growth of indigenous
microorganisms in the soil and increases the rate of bacterial
degradation. The operation will continue until soil samples meet
the remediation goals. Finally, the drill cuttings will be dis-
posed of off-site in a hazardous waste landfill.
This alternative, exclusive of the groundwater action, will take
no more than eleven years to complete. The approximate costs for
this remedy, including groundwater costs, range from $2,742,000
to $2,805,000 capital; $316,000 to $396,000 annual 0/M; and
$6,133,000 to $6,318,000 present worth.
Alternative 4: Mechanical Soil Washing
This remedy represents excavation and treatment of contaminated
surface soil in Carver Terrace. Soils exceeding the remedial
goals will be excavated to approximately a one foot depth; these
soils will be transported to the Kennedy Sand & Gravel area for
treatment. Lots being excavated will be identified with yellow
tape, and personnel will be assigned to keep children out of the
excavation. Air will be monitored during the excavation so that
any emissions will be known and corrective actions can be taken.
Each yard excavated will be filled with dirt on the same day as
the excavation to minimize any exposure caused by remediation.
After that, the lots will be graded, covered with sod, and land-
scaped in the same manner as before excavation.
The contaminated soil along with the drill cuttings will be
treated in a mixer by adding surfactants to wash the contaminants
from the soil. The choice of the surfactant will be determined
during further pilot testing in the Remedial Design. The washing
solution will be treated at the groundwater treatment plant. The
22
-------
treated soils will be disposed of at Kennedy Sand & Gravel assum-
ing that the soils will show no further leaching.
This alternative, exclusive of the groundwater action, will take
approximately two years to complete. The approximate costs for
this remedy, including groundwater costs, range from $3,269,000
to $3,332,000 capital; $316,000 to $329,000 annual 0/M; and
$6,250,000 to $6,435,000 present worth.
Alternative 5: On-site Incineration
This remedy also represents excavation and treatment of contami-
nated surface soil in Carver Terrace. The soils will be exca-
vated and lots re-established in the same manner as for Mechan-
ical Soil Washing. In this alternative, the contaminated soil
will be thermally treated in a mobile incinerator equipped with
appropriate air pollution control devices. The components of the
incinerator will be shipped to the site and built in the Kennedy
Sand & Gravel area. The incinerator will then be tested with
small volumes of soil to ensure that the incineration will comply
with Federal and State requirements. When the incinerator is
ready for full operation, the soil will be excavated, mixed with
the drill cuttings and fed into the incinerator. Scrubber and
blowdown water will be treated at the groundwater treatment
plant. After incineration, the treated soil will be stockpiled
temporarily and disposed in the gravel pits if it can be
delisted. Otherwise, the treated soil will be disposed of in a
hazardous waste landfill.
This alternative, exclusive of the groundwater action, will take
approximately three years to complete. The approximate costs for
this remedy, including groundwater costs, range from $5,207,000
to $6,910,000 capital; $316,000 to $329,000 annual 0/M; and
$8,188,000 to $10,013,000 present worth.
Alternative 6: Off-site Incineration
This remedy also represents excavation and treatment of contami-
nated surface soil in Carver Terrace. The soils will be exca-
vated and lots re-established in the same manner as for Mechan-
ical Soil Washing. In this alternative, the contaminated soils
and drill cuttings will be transported to an incinerator located
off-site and incinerated there.
This alternative, exclusive of the groundwater action, will take
approximately six years to complete. The approximate costs for
this remedy, including groundwater costs, range from .$23,054,000
to $23,117,000 capital; $316,000 to $329,000 annual 0/M; and
$26,035,000 to $26,220,000 present worth.
Altenative 7; Off-site Landfill
This remedy represents excavation and containment of contaminated
surface soil in Carver Terrace. The soils will be excavated and
lots re-established in th same manner as for Mechanical Soil
23
-------
Washing. In this alternative, the contaminated soils and drill
cuttings will be contained in a landfill located off-site and
disposed of there.
This alternative, exclusive of the groundwater action, will take
approximately two years to complete. The approximate costs for
this remedy, including groundwater costs, range from $5,102,000
to $5,165,000 capital; $316,000 to $329,000 annual 0/M; and
$8,083,000 to $3,268,000 present worth.
Alternative 8j_ Passive Soil Washing
This remedy represents excavation and treatment of contaminated
surface soil in Carver Terrace. The soils will be excavated and
lots re-established in the same manner as for Mechanical Soil
Washing. In this alternative, the contaminated soils and drill
cuttings will be transported to Kennedy Sand & Gravel and dis-
posed of in the gravel pits so that the soils can be treated
along with the soils within the aquifer. The surfactants added
to the re-injected groundwater will wash the contaminants from
the soil. As with alternative 4, the choice of the surfactant
will be determined during further pilot testing in the Remedial
Design. The washing solution will be collected with the ground-
water and treated at the groundwater treatment plant.
This alternative, exclusive of the groundwater action, will take
approximately two years to complete the excavation but up to 30
years to complete the remediation of the soils proper. The esti-
mated costs for this remedy, including groundwater costs, range
from $1,863,000 to $1,926,000 capital; $319,000 to $332,000
annual 0/M; and $4,867,000 to $5,052,000 present worth.
7.2 EVALUATION OF ALTERNATIVES
OSWER Directive 9355.0-21 prescribes nine criteria which EPA con-
siders in selecting a remedy for a CERCLA site. These criteria
address the specific requirements of Section 121(b)(l) of SARA.
*
EPA has assessed the degree to which each remedial alternative
meets the nine selection criteria; Table 3 summarizes this
assessment. The following values were used to compare the remedy
selection criteria:
+ Alternative would exceed a criterion compared to other
alternatives.
0 Alternative can meet the selection criterion.
Alternative would not meet the criterion without special
efforts.
The rationale for the ratings assigned in this table follows:
24
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TABLE 4
COMPARISON OF REMEDIAL ALTERNATIVES
KOPPERS TEXARKAMA STREET SITE
/
COMPLY WITH
ENV I RONMENTAL
LAWS
REDUCE
TOX 1 C I T Y
MOBIL 1 TY
VOLUME
SHORT-TERM
EFFECTIVENESS
LONG-TERM
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IMPLEMENTABIL1TY
( 1 )
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COMMUNITY
ACCEPTANCE
PROTECTION OF
HUMAN HEALTH &
THE ENVIRONMENT
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Symbols:
» = Compared to others, alternative exceeds criterion.
0 » Alternative can be designed to meet the criterion.
» Compared to others, alternative « i I I need special efforts
to meet the criterion.
Notes:
( 1 )
(2)
Units of million dollars, reflects the maximum range of
the cost estimates including the costs for groundxater
remediation ($2,000,000 capital, $0.3 0/M, $4,000,000
present worth)
Based on 30 years at 10X interest
25
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Consistency with Other Environmental Laws
Appendix B identifies the Federal and State applicable or
relevant and' appropriate requirements (ARARs) for each
alternative.
No Action is rated as "-" because it violates the intent of
SARA Section 121 regarding the selection of a remedy and does
not comply with the National Contingency Plan provisions to
respond to a threat of release.
Off-site Landfill is rated as "-" because it may not comply
with the proposed requirements for PAHs in CERCLA soil and
debris under the Land Disposal Restrictions (40 CFR Part
268). Some of the contaminated soil may have originated from
spills of creosote (RCRA waste U051). The anticipated regu-
lations will require some degree of treatment before dis-
posal.
Capping is also rated as "-" because it does not comply with
the RCRA requirements for caps.
All other alternatives are rated as "0" since they can be
designed to meet any ARARs. Specifically, for the Land Dis-
posal Restrictions, some of the drill cuttings from the Reme-
dial Investigation and all of the creosote recovered in the
groundwater treatment system are subject to Land Disposal
Restrictions. There are no present promulgated regulations
applicable to these soils. All alternatives using excavation
include treatment methods which comply with the statutory
requirement to "...substantially diminish the toxicity of the
waste or substantially reduce the likelihood of migration of
hazardous constituents from the waste so that short-term and
long-term threats to human health and the environment are
minimized." The creosote recovered in the groundwater treat-
ment system is subject to recent regulations which require
substantial reduction in concentration. This will be
attained by either recycling (no disposal) or incinerating
the creosote.
Reduction of Toxicity. Mobility and Volume
No Action is rated as "-" because it does not reduce toxic-
ity, mobility or volume of contaminants in Carver Terrace
soils. However, natural biodegradation will eventually
reduce some contamination.
Capping and Off-site Landfill are rated as "-" for toxicity
and volume for the same reasons as for No Action, and as "0"
for mobility since the contaminants would be contained.
Mechanical Soil Washing, Passive Soil Washing, and In Situ
Biodegradation are rated as "0" because the concentration,
volume, and leaching potential of organic contaminants in
Carver Terrace soils would be reduced.
26
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On-site Incineration and Off-site Incineration are rated as
"+" for toxicity and mobility since they provide the greatest
reductions, and are rated as "0" for volume because the vol-
ume of contaminants in Carver Terrace soils will be reduced.
Short-Term Effectiveness
No Action is rated as "0" because the maximum possible degree
of protection would be quickly achieved and would not result
in increased exposures to workers or residents during the
remedial actionn.
Capping is rated as "+" because the remedy can be quickly
installed, and Carver Terrace residents would not likely be
exposed to contaminants during remediation.
In Situ Biological Treatment and Passive Soil Washing are
rated as "-" because the time to complete the soil treatment
in Carver Terrace can take over ten years, and, for Passive
Soil Washing, there could be additional exposure to residents
during excavation.
Off-site Incineration and Off-site Landfill are rated as "-"
because, as for all alternatives requiring excavation, on-site
residents may become exposed to additional contaminants dur-
ing excavation and materials handling, and there is always a
potential risk for spills with off-site transportation of
wastes. In addition, Off-site Incineration may take up to six
years for completion.
On-site Incineration and Mechanical Soil Washing are rated as
"0" because, although excavation and materials handling could
pose additional risks to the health of on-site residents dur-
ing remediation, these can be controlled by dust suppression
and temporary relocation (if necessary), and the time to
complete the remediation is less than three years.
Long-Term Effectiveness and Permanence
No Action is rated as "-" because the potential human health
and environmental risks would not be abated.
Capping is rated as "-" because it would require long-term
monitoring and maintenance to ensure that the remedy for
Carver Terrace soils remains effective.
Off-site Landfill is rated as "-" because it would require
long-term monitoring and maintenance at the disposal facility
to ensure that soil contaminants do not leach after mixture
with contaminants from other sites.
Mechanical Soil Washing, Passive Soil Washing and In Situ
Biodegradation are rated as "0" since these remedies destroy
health-threatening contamination in Carver Terrace soils.
27
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On-site Incineration and Off-site Incineration are rated as
"+" because they could destroy most contamination from Carver
Terrace soils.
Implementability
On-site Incineration, Passive Soil Washing, and In Situ
Biodegradation are rated as "-" because they require a sig-
nificant amount of testing. On-site Incineration requires
one or several test burns to determine the manner the optimal
way to operate the incinerator. Passive Soil Washing and In
Situ Biodegradation have not been tested using the site
soils; further testing is manditory to assure that these
methods can be implemented. In addition, the Texas Air Con-
trol Board would need to be consulted in the design and oper-
ation of an incinerator.
Mechanical Soil Washing is rated as "0" because it can be
implemented with known equipment and has already been tested
with site soils.
No Action, Capping, Off-site Incineration and Off-site Landfill
are rated as "+" because they can be implemented without
major capital acquisitions.
Cost
Table 3 lists the estimated costs for each remedial action
alternative. This table includes capital, operation and
maintenance, and present worth costs. Replacement costs are
factored into the operation and maintenance costs. The No
Action alternative has the lowest present worth cost of all
alternatives followed by Passive Soil Washing, Capping, In
Situ Biodegradation, Mechanical Soil Washing, Off-site Land-
fill, On-site Incineration, and Off-site Incineration in
increasing order of cost. All alternatives require long-term
operation and maintenance costs beyond 5 years due to the
groundwater remediation and fence maintenance.
Community Acceptance
Comments from local residents received at the public meeting
on July 20, 1988, and during the public comment period have
one central theme; there is general agreement among local
residents that only permanent relocation will fully protect
their health from exposure to contaminated soils.. EPA has
proposed to treat only those soils that could pose a health
threat. Thus, some measurable amounts of contaminants will
remain on site. Another major concern of the public is the
potential adverse impact that this Superfund site will have
on their property values.
28
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would include, but not necessarily be limited to, inspections of
surface vegetation, ensuring proper drainage, proper operation of
any actions such as groundwater treatment which may extend beyond
the time required"- for the source control remedy, and periodic
fence repair. The details of these activities will be defined in
the Operation and Maintenance Plan of the remedial design. The
monitoring data will be evaluated during the Agency's 5-year
review, in accordance with SARA Section 121 (c), to determine if
any corrective action is necessary.
Protection Achieved: This remedial goal prevents against an
excess lifetime increased cancer risk of 3xlO~5 and keeps expo-
sure to non-carcinogenic compounds below the reference dose. EPA
is using a cancer risk of 3xlO~5 as a remedial goal instead of
1x10 because of the cancer potency factors for carcinogenic
PAHs. EPA considered all potentially carcinogenic PAHs to be as
potent as benzo(a)pyrene because the agency has not published
cancer potency factors for the other PAHs. EPA recognizes that
the other potentially carcinogenic PAHs may be less potent by
factors of 10 to 100 times, and is now in the process of develop-
ing cancer potency factors for other PAHs. Benzo(a)pyrene repre-
sents 13% of the carcinogenic PAHs at this site. Therefore, EPA
is using a cancer risk of 3x10 cancer risk value by considering
that this risk number may be high by a factor of 10.
8.2 SIGNIFICANT DIFFERENCES FROM THE PROPOSED PLAN
On July 1, 1988, EPA presented the proposed plan for remediation
at this site. The proposed plan called for either mechanical
soil washing, passive soil washing, or in situ biodegradation for
contaminated soils in Carver Terrace, and it also called for
groundwater collection and treatment with activated carbon.
In this Record of Decision, EPA is selecting mechanical soil
washing for contaminated soils and either activated carbon or a
fluidized carbon bed for groundwater. EPA asked for community
input regarding the preference for in situ biodegradation as an
alternative means of treatment. The citizens during the public
meeting demonstrated a strong preference for remedies which will
quickly reduce soil contamination. Therefore, EPA is not
selecting in situ biodegradation.
EPA also is not selecting passive soil washing. Passive soil
washing has not been demonstrated at this or other sites; it nay
not work. In particular, the soils from Carver Terrace are less
porous than those in the aquifer, and groundwater may flow around
the excavated Carver Terrace soils instead of through them. EPA
is concerned that passive soil washing may not provide sufficient
remediation for soils and that further actions including excava-
tion and treatment using soil washing may be necessary to com-
plete remediation.
EPA reviewed the information about activated carbon and fluidized
carbon bed treatment. Both methods can achieve the required
performance and have similar costs as shown in the Feasibility
32
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Study. Both methods require the same type of construction. EPA
believes that there are no decisive differences between these two
methods and is therefore selecting both.
8.3 STATUATORY DETERMINATIONS
Section 121 of SARA requires the selected remedy to be protective
of human health and the environment, be cost-effective, use per-
manent solutions and alternative treatment or resource recovery
technologies to the maximum extent possible, be consistent with
other environmental laws, and have a preference for treatment
which significantly reduces the toxicity or mobility of the haz-
ardous substances as a principle element. EPA believes that the
selected remedy best fulfills the statuatory and selection cri-
teria as compared to the other solutions evaluated herein.
Protection of Human Health and Environment
The selected remedy will reduce soil contamination to prevent an
additional risk of cancer of 3xlO~, prevent any non-carcinogenic
hazards, and prevent continued leaching of creosote compounds
from soils into groundwater. It does this by excavating soils in
Carver Terrace and treating the soils to below health-threatening
levels. It also prevents the continued off-site migration of
contaminated groundwater, removes and treats the source of con-
tinued groundwater contamination, and allows for natural attenua-
tion of groundwater to background levels. It does this by treat-
ment; therefore, the risks will not increase in the future due to
a failure of the remedy. Short-term risks will be controlled by
covering excavations with clean soil at the end of the day, sup-
pressing dust, temporarily relocating sensitive residents, and
maintaining the fence around Kennedy Sand & Gravel throughout the
groundwater remediation on that property.
Cost-Effective
The present worth of the selected remedy is $6.4 million and is
the lowest cost of all alternatives which either meet or exceed
the nine evaluation criteria. EPA believes that remedies with
higher costs do not provide any further benefits. EPA also
believes that remedies with lower costs may have slow or incom-
plete remediation or do not provide for permanent treatment.
Therefore, EPA believes that the overall effectiveness of the
selected remedy is a reasonable value for the costs.
Permanent Solutions to Maximum Extent Possible
EPA believes the selected remedy is the most appropriate solution
for meeting the remedial goals by providing the best balance
among the evaluation criteria for the alternatives. This remedy
provides effective protection of human and environmental recep-
tors over the short- and long-term, protects against off-site and
deeper migration of groundwater, is readily implemented, is cost-
effective, permanently treats those contaminants excavated from
soil or extracted from groundwater, and recycles (if possible)
33
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recovered creosote. Carver Terrace soils are treated by desorb-
tion, and groundwater is treated by physical/chemical and/or
biological treatment. However, long-term monitoring and mainte-
nance of the groxmdwater collection and treatment system will be
necessary due to the length of time necessary to cleanse the
groundwater. Long-term maintenance of the fence around Kennedy
Sand & Gravel will also be necessary to protect the groundwater
collection and treatment system and reduce risks of exposure of
contaminants left on that property.
Consistent with Other Environmental Laws
The selected remedy can be designed to attain other environmental
laws. The laws applicable or relevant and appropriate to CERCLA
activities are called ARARs. Appendix B lists all the ARARs
initially identified for this site in the Feasibility Study. The
specific ARARs for the selected remedy are described below:
National Primary Drinking Water Standards; Groundwater reme-
diation will prevent continued off-site migration of contami-
nants exceeding these levels during remediation by collecting
all groundwater in the upper aquifer which may flow off-site.
After remediation, the aquifer will return to background
levels because the contaminant source will be removed.
National Secondary Drinking Water Standards; Groundwater
remediation will prevent continued off-site migration of con-
taminants exceeding these levels during remediation by col-
lecting all groundwater in the upper aquifer which may flow
off-site. After remediation, the aquifer will return to back-
ground levels because the contaminant source will be removed.
Maximum Contaminant Level Goals (MCLGs); This is not an
ARAR, but is another factor to be considered for contaminants
where the MCLs have yet to be promulgated. Groundwater reme-
diation prevents continued off-site migration of contaminants
exceeding these levels during remediation by collecting all
groundwater in the upper aquifer which may flow off-site.
After remediation, the aquifer will return to background
levels because the contaminant source will be removed.
Ambient Water Quality Criteria: Discharge of excess treated
water (that not re-injected) will comply with these criteria
for compounds not regulated by State water quality standards.
The discharge at the stated treatment levels, after dilution
with Wagner Creek, will not exceed these criteria.
National Pollutant Discharge Elimination System; Discharge
of excess treated water will comply with Best Available Tech-
nology and water quality standards. Treatment performance is
equal to that required for the Organic Chemical, Plastics,
and Synthetic Fibers (OCPSF) effluent guidelines which were
promulgated by EPA for discharges from organic chemical
facilities including those manufacturing creosote-type pro-
ducts. The discharge at the stated treatment levels, after
34
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dilution, will not exceed the water quality standards.
National Pretreatment Standards; Discharge of excess treated
water will comply with these standards by also complying with
Best Available Technology for OCPSF facilities. Pretreatnent
requirements for these facilities are equal to those for BAT.
Occupational Safety and Health Act; Remedial action will be
conducted consistent with the OSHA regulations for personnel
protection and safety.
Endangered Species Act: The RI identified several endangered
species which are indigenous to the area around Texarkana.
EPA will coordinate with the U. S. Fish and Wildlife Service
to determine if endangered species reside on the site and
identify the measures needed to protect those species.
Executive Order on Floodplains; The entire site is within a
100 year floodplain. EPA has determined that remedial action
must take place here because the contaminants are physically
within the floodplain. EPA has included several elements in
the selected remedy to minimize any harm to the floodplain.
The remedy includes grading backfilled residential yards as
close to natural contours as possible, using erosion control
measures in Kennedy Sand & Gravel, and designing flood pro-
tection for the groundwater treatment plant.
Hazardous Materials Transportation Act; Off-site transport
of recovered creosote will require handling in a manner con-
sistent with this act.
RCRA Standards Applicable to Generators and Transporters of
Hazardous Waste; Off-site transport of recovered creosote
for incineration or recycling will require manifesting.
Releases from Solid Waste Management Units (40 CFR 264(F) ) ;
Groundwater remediation will prevent continued off-site
migration of contaminants exceeding these levels during reme-
diation by collecting all groundwater in the upper aquifer
which may flow off-site. After remediation, the aquifer will
return to background levels because the contaminant source
will be removed.
Tanks (40 CFR 264(J}}: Tanks temporarily storing recovered
creosote will be designed to comply with this regulation.
Land Disposal Restrictions; Restrictions have yet to be
promulgated for CERCLA soils and debris contaminated with
RCRA wastes. Despite the absence of regulations, the treat-
ment methods used as parts of the remedial action satisfy
the statutory requirement to "...substantially diminish the
toxicity of the waste or substantially reduce the likelihood
of migration of hazardous constituents from the waste so that
short-term and long-term threats to human health "and the
environment are minimized."
35
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Texas Allowable Limits of Metals in Drinking Water: Ground-
water remediation will prevent continued off-site migration
of contaminants exceeding these levels during remediation by
collecting all groundwater in the upper aquifer which may
flow off-site. After remediation, the aquifer will return to
background levels because the sources will be removed.
Texas Water Quality Standards for Surface Waters: Discharge
of excess treated water will comply with these standards. The
discharge at the stated treatment levels, after dilution with
Wagner Creek, will not exceed these standards.
Texas Prohibition of Air Contaminants which Adversely Affect
Human Health: Air will be monitored during excavation to
observe compliance. Dust suppression methods will be used to
minimize any release by this route. Some residents, espec-
ially those with sensitivities to dust or with chronic health
problems, may be temporarily relocated during excavation.
Texas Storage of Volatile Organic Compounds: Tanks tempor-
arily storing recovered creosote and associated volatile
compounds will be designed to comply with this regulation.
Texas Oil/Water Separators: The oil/water separator in the
groundwater treatment system will be designed to control
volatile emissions as required by this regulation.
Preference for Treatment as a Principal Element
The principal threats at this site are present exposure to con-
taminated soils in Carver Terrace and potential future exposure
to contaminated groundwater. The selected remedy uses treatment
for the remediation of both Carver Terrace soils and site ground-
water. Mechanical soil washing will desorb carcinogenic PAHs
from soils and allow for eventual treatment along with the recov-
ered groundwater. Oil/water separation and either activated
carbon adsorption or fluidized carbon bed treatment will remove
contaminants from groundwater.
8.4 FUTURE ACTIONS
The selected remedy completes the remediation of the principal
threats at the site. The proposed schedule for remediation,
assuming that Remedial Design and Remedial Action negotiations
fail, is as follows:
Approve Remedial Action by Signing
the Record of Decision September 1988
Start Remedial Design December 1988
Complete Remedial Design December 1990
Start Remedial Action March 1991
36
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APPENDIX A
RESPONSIVENESS SUMMARY
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Koppers Texarkana
Community Relations Responsiveness Summary
This Community Relations Responsiveness Summary has been prepared
to provide written responses to comments submitted regarding the
proposed plan of action at the Koppers Texarkana Superfund site.
The summary is divided into two sections:
Section I: Background of Community Involvement and Concerns.
This section provides a brief history of community interest and
concerns raised during the remedial planning activities at the
Koppers Texarkana site.
Section II: Summary of Major Comments Received. The comments
are summarized and EPA's responses are provided.
I. Background of Community Involvement and Concerns
In October 1984, EPA proposed to add the Koppers Texarkana Street
site to the National Priorities List. EPA held an initial commu-
nity meeting on October 18, 1984, to discuss the reasons for
listing the site on the National Priorities List (NPL). On Janu-
ary 3, 1985, EPA held a second meeting to describe the initial
response actions to be taken at the site. EPA held a third meet-
ing on May 7, 1985, to announce that the Koppers Company would
conduct the site investigation under EPA's supervision; EPA also
presented the schedule for this investigation. Fact sheets were
periodically mailed to local residents and interested parties to
describe the field activities.
EPA issued a press release on June 23, 1988, announcing the con-
clusion of the Remedial Investigation and Feasibility Study, the
availability of reports on those studies, and EPA's proposed
alternative. The press release also informed the public that the
comment period would began on July 1, 1988, and end on July 30,
1988. The press release also invited all interested citizens to
an open house on June 28, 1988.
EPA prepared a fact sheet which described remedial alternatives
along with the EPA preferred remedy; this was mailed to the
interested citizens and nearby residents on June 24, 1988. The
fact sheet gave a brief site history, described the Superfund
process and remedial alternatives, provided details on the public
comment period and the public meeting to be held on July 20,
1988.
On June 27-28, 1988, EPA conducted on-site interviews with the
homeowners in the Carver Terrace subdivision and gave each resi-
dent a copy of the fact sheet. EPA met with the Mayor and Mayor
Pro Tern of Texarkana on June 28, 1988, and also conducted an open
house at the Southwest Center, 3222 West 7th Street, in Texarkana
to present the alternatives to the homeowners in Carver Terrace
and answer their questions.
A-l
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The local residents at the public meeting expressed a strong
preference for quick removal of contaminants from their
yards. Therefore, all alternatives requiring excavation are
rated as "0"-with the other alternatives as "-".
Some residents expressed concern about several concerns
related to the site. Flooding was discussed as a possible
migration pathway for contaminants. Also, some residents
were concerned about short-term exposure during excavation in
their yards. To address these concerns, EPA will require
that the Kennedy Sand & Gravel property be graded to prevent
runoff from entering Carver Terrace. EPA will also survey
the residents of Carver Terrace to identify those residents
particularly sensitive to dust or with chronic health
problems so that those residents can be temporarily relocated
during excavation of their yards. EPA will also work with
each resident whose yard is excavated to assure that the
replacement of the yard will conform as close as possible to
the state of the yard before excavation.
The public questions and comments including EPA's responses
are contained in Appendix A, "Responsiveness Summary."
State Acceptance
The Texas Water Commission (TWC), the State regulatory agency
for CERCLA sites, was briefed on the remedial alternatives on
June 3, 1988. The TWC notified EPA by letter that the TWC
had no objections to the selected remedy (see Appendix D).
Overall Protection of Human Health and the Environment
No Action is rated as "-" because it does not provide ade-
quate protection from the potential risks involved with leav-
ing untreated soils in Carver Terrace on-site.
Capping is rated as "-" because it only protects health by
containing the Carver Terrace soils. There is some potential
for exposure to soil or release to groundwater in the future
if the cap fails and, most importantly, it is the least-
preferred alternative where practicable treatment technolo-
gies are available. However, the groundwater collection and
treatment part of this alternative provides some permanent
protection by removing and treating the groundwater contami-
nants.
In Situ Biodegradation is rated as "0" because it destroys
some organics in the excavated Carver Terrace soils.
On-site Incineration, Mechanical Soil Washing, and Passive
Soil Washing are rated as "0" because they provide protection
of human health by excavating the soils, and they destroy
most organics in the excavated soils.
29
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Off-site Landfill and Off-site Incineration are rated as "+"
because they remove health-threatening contaminants from the
site.
8. SELECTED REMEDY
Based on the available data and analyses identified in the admin-
istrative record, EPA is selecting Mechanical Soil Washing as the
most appropriate solution for remediating principal problems at
this site. This alternative remediates contaminated soils in
Carver Terrace and contaminated groundwater throughout the site.
8.1 DESCRIPTION OF THE REMEDY
Carver Terrace Soils; The remedy requires excavation of lots
where the sum of the carcinogenic PAHs in soil exceeds 100 ppm.
The lots within the general area of contamination identified
during the Remedial Investigation will be sampled during the
Remedial Design. The volume of soils potentially requiring reme-
diation ranges from 3,300 to 19,400 cubic yards. Those lots with
soils exceeding the remedial goal of 100 ppm carcinogenic PAHs
will be excavated to an approximately one foot depth. Front and
back yards will be separately considered, that is, if only the
back yard exceeds the goal, then only the back yard will be exca-
vated. Short-term risks will be controlled by covering excava-
tions with clean soil at the end of the day, suppressing dust,
and temporarily relocating sensitive residents if necessary.
Excavated yards will be backfilled with clean soil purchased from
outside the site, graded to prevent ponding of rainfall in yards,
and covered with sod to prevent erosion and to replace the yard.
In addition, any existing landscaping destroyed during the exca-
vation will be replaced.
Excavated soils will be transported to Kennedy Sand & Gravel
where a soil washing unit will be constructed. This unit will
desorb the contaminants from the soils using surfactants; the
surfactants and wash water will be treated at the groundwater
treatment plant. Cleansed soils will be disposed in the gravel
pits at Kennedy Sand & Gravel if the soils can be delisted by
meeting the remedial goal of 100 ppm carcinogenic PAHs and also
showing no continued leaching potential using the EPA Toxicity
Characteristic Leaching Procedure (TCLP) test. Otherwise, the
soils will need to be disposed of at an off-site hazardous waste
facility.
Stratum I Groundwater: The remedy also requires collection and
treatment of non-aqueous phase liquids (NAPLs) in groundwater in
stratum I. Collection trenches will be installed around and
across the Kennedy Sand & Gravel part of the site. In addition,
a well nest and collection station may be installed in a vacant
area in Carver Terrace to the north of West Third Street to help
collect a pocket of NAPLs located there. Any excavation neces-
sary to install the trenches will be backfilled with the same
material excavated and covered with an erosion-preventing mater-
ial. Approximately 45 million gallons of groundwater will need
30
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to be processed several tines to recover and treat the NAPLs.
Groundwater 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 groundwater collection will cease and the ground-
water will be allowed to naturally attenuate to background
levels. Monitoring will be used to ensure that natural attenu-
ation is continuing.
The groundwater and NAPLs will be treated at an on-site wastewater.
treatment plant constructed in the southeast corner of the Ken-
nedy Sand & Gravel property. The treatment plant will be con-
structed with protection from a 100 year flood. Treatment will
include oil/water separation followed by either an activated
carbon or fluidized carbon bed system. Any NAPLs collected and
separated from the groundwater will be recycled as creosote or
incinerated off-site. Spent carbon will be regenerated off-site.
The water will be treated to levels equal to the Best Available
Treatment requirements for the Organic Chemical, Plastics, and
Synthetic Fibers (OCPSF) industry. Cleansed groundwater will be
re-injected into the aquifer along with surfactants to help
recover the NAPLs. Any excess water will either be discharged to
Wagner Creek or to a local wastewater treatment plant.
Drainage Ditch Sediments: Sediments in the bend of the drainage
ditch which cuts across the old lagoon area within Kennedy Sand &
Gravel will be excavated and used in the pilot testing of the
soil washing unit.
Drill Cuttings; The drill cuttings collected during the Remedial
Investigation will be combined with the excavated Carver Terrace
Soils, treated in the mechanical soil washing unit, and disposed
along with the treated Carver Terrace soils.
Kennedy Sand and Gravel Property: This action is based on site
control, imposition of necessary deed notices, and restriction of
access to this part of the site by use of a fence throughout the
Remedial Action.
Stratum II Confined Zone: This zone will be allowed to naturally
attenuate following remediation. The zone will be monitored to
ensure that it is being naturally cleansed.
Operation and Maintenance: The need for future operation and
maintenance will be minimized since the primary sources of con-
tamination will be removed through treatment. Site operation and
maintenance will include monitoring of groundwater wells, ambient
air (during remediation only), and Wagner Creek water. The
length of the groundwater and Wagner Creek monitoring program
will be determined during the Remedial Design based on the
results of the pilot test of the groundwater collection system.
This sampling program will monitor the effectiveness of the
selected remedy and provide the data necessary to trigger future^
corrective action, if necessary. Additional site maintenance
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On July 20, 1988, at 7:00 pm, EPA conducted a public meeting at
the Southwest Center in Texarkana to brief the homeowners and
citizens on the study findings, reviewed the alternatives consid-
ered, presented EPA's preferred remedy, answered questions and
received comments. Seventy people attended this meeting.
II. Summary of Malor Comments Received
During the public comment period, there were comments and questions
regarding the following:
Comment 31: Why was incineration ruled out? It seems to be a
permanent and quick remedy.
EPA Response: Incineration was one of the remedies examined in
fine detail with the criteria EPA uses to select Superfund rem-
edies: protection of health, compliance with environmental laws,
long- and short-term effectiveness, implementability, cost, and
reduction of toxicity, mobility, and volume. EPA compared incin-
eration with soil washing, the selected remedy. These two reme-
dies provide most of the same type of advantages and disadvan-
tages. Soil washing is slightly more effective over the short-
term because it does not pose possible problems with air emis-
sions which incineration does. Both reduce the toxicity, mobil-
ity, and volume, although incineration provides a larger reduc-
tion. Finally, incineration is twice as costly as soil washing.
Based on the balance of the above factors, EPA believes that soil
washing provides more advantages than does incineration. There-
fore, incineration was not proposed.
Comment *2: Which soil washing remedy is EPA proposing? It
appears EPA is thinking about the mechanical one. Soil washing
seems to be a more practical remedy because you are going to get
rid of the contaminants much faster.
EPA Response; EPA proposed both methods, but EPA is only select-
ing mechanical soil washing as the remedy. In concept, both
methods for soil washing can effectively destroy contaminants
with one, passive soil washing, being the less costly. However,
EPA does not have enough data to determine if passive soil wash-
ing will work at this site and is concerned that the soils will
not receive the necessary degree of treatment under passive soil
washing. EPA is also unsure how this method can be effectively
tested during the Remedial Design.
Comment J3: How long will it take to complete the bioremediation
pilot test study?
EPA Response; If bioremediation were to be selected, then the
pilot tests would take approximately one year. Most of the
action would occur during the first few months. However, biore-
mediation is not the selected remedy.
Comment *_4: When EPA digs up the soil to remediate it, where
will EPA get the soil to put back into the yards?
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EPA Response; EPA has not yet contracted with a supplier of
clean top soil, but EPA intends to use a supplier located in the
Texarkana area but away from the Superfund site.
Comment |5* Will EPA scrape out the black stuff (dried tars) in
the yards?
EPA Response; EPA intends to remediate yards in Carver Terrace
where surface soils exceed the cleanup levels for contaminants.
EPA will remove dried tars in those yards.
Comment |6: What will EPA do about the contamination under the
houses?
EPA Response: EPA feels that any contamination under houses
poses no threat to health or further migration of contaminants.
The houses in Carver Terrace are constructed on concrete slabs.
First, the slabs prevent access to soils under the house. At
other sites, EPA has used a barrier similar to a concrete slab to
prevent exposure to soils. Second, the slabs prevent water from
reaching those soils and thereby do not allow contamination to
move into the groundwater. Therefore, EPA is not requiring reme-
diation of contamination under the houses.
Comment 37.; How much will the remediation cost? Who will pay for
the remediation, EPA or Koppers?
EPA Response; EPA estimates the cost of the selected remedy to
be $6 million dollars, but could be as high as $8 million. If a
potentially responsible party such as the Koppers Company offers
to construct and operate the remedy under EPA's oversight, then
that party would pay for the remedy. If no such party offers to
do so, then EPA will pay for the remedy and will try to recover
the costs in court.
Comment j*8; Who is responsible for this site? Are the develo-
pers responsible?
EPA Response; Under the Superfund laws, present owners or opera-
tors of properties, as well as the owners and operators during
the time hazardous substances were disposed, can be responsible
for the costs of remediating the site. Several courts have
decided that past property owners who did not own the property
during the time when hazardous substances were disposed are not
responsible under the law. Carver Terrace, Inc., is a property
owner of this type. Therefore, EPA has not contacted Carver
Terrace, Inc., about responsibility.
Comment *9: I want EPA to start remediating the site. I do not
believe that the site can or will be cleaned up.
EPA Response: EPA will issue a Record of Decision in September
of 1988 to select a remedy for this site. EPA will start design-
ing the remedy within six months following the Record of Decis-
ion. EPA has selected similar remedies at other former wood
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preserving sites, and is confident that the selected remedy will
remediate the site so that the health of residents is protected.
Comment #10; Will" you remediate everyone's yard?
EPA Response: During the Remedial Investigation, EPA identified
two general areas in Carver Terrace where contaminants were found
at levels which could pose a threat to health. These areas were
on the south side of West Third Street and roughly along Fannin
Street. EPA will resample the yards in these areas and remedi-
ate those yards where contamination is found above the remedial
levels. EPA expects that not every yard will require
remediation.
Comment 111; What will EPA do about the groundwater and surface
water to keep the aquifer clean and prevent contamination from
going into Days Creek?
EPA Response: From the Remedial Investigation, EPA found oily-
type contaminants in the groundwater moving to the south and also
entering Wagner Creek, a tributary of Days Creek. EPA required
the Koppers Company to control the discharge into Wagner Creek
with an absorbent boom which collects the contaminants. EPA's
selected remedy requires that the contaminants causing ground-
water contamination will be removed by a collection system and
treated using either activated carbon or a fluidized carbon bed.
Comment 312: I do not want the soil burned here. I would like
the fluidized bed groundwater treatment to be used.
EPA Response: First, EPA is not selecting any incineration
remedy. Second, EPA is selecting both the fluidized carbon bed
and activated carbon groundwater remedies; both will be tested
during the Remedial Design phase to determine which one works the
best. EPA's studies for the site show that both can treat the
groundwater to the levels needed to remediate the site.
Comment f13: Can the residents be removed until the site is
remediated?
EPA Response: EPA does not believe that there is a health hazard
to residents at this site that warrants temporary relocation for
all residents during remediation. EPA has assessed the threats
to public health in the chapter of the Feasibility Study report
called the "Public Health Evaluation Assessment". In this chap-
ter, EPA described the amounts of site-related contaminants that
a resident could become exposed to, and EPA estimated what this
exposure could mean in terms of threats to health. EPA's calcu-
lations show that, for the most contaminated areas in Carver
Terrace, the risk of cancer from 70 years of exposure is 7xlO~4.
This does not consider any protection provided by the soil and
sod barrier. Over the three years needed to remediate the yards,
the risk will be over 20 times less, and within the acceptable
levels which EPA has used for remediating other sites.
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In addition, EPA will take actions to protect residents from
exposure during remediation. EPA will provide security people to
keep children out of the work areas and will close all excava-
tions at the end- of the work day. EPA will monitor air to assure
that residents will not become exposed; if EPA notes contaminants
in the air, then EPA will immediately stop the activities and
cover over any excavation.
EPA recognizes that certain residents, because of their partic-
ular sensitivity to dust or other unique factors, may need to be
temporarily relocated for one to two weeks while their yards and
surrounding yards are excavated. EPA will contact the residents
during the Remedial Design to identify those residents who may
need special attention.
Comment f14: Koppers proposes that alternative SL-4E (Excava-
tion, Passive Soil Washing, Monitoring, Institutional Controls),
as described in the FS report, be selected. If, however, EPA
acts to change the cleanup levels, Koppers reserves its full
right to re-examine its recommendation for a remedial alternative
for unsaturated soils.
EPA Response: EPA does not agree with this proposal. EPA is
selecting mechanical soil washing as the remedy. In concept,
both methods for soil washing can effectively destroy contami-
nants with one, passive soil washing, being the less costly.
However, EPA does not have enough data to determine if passive
soil washing will work at this site, nor did the Koppers Company
submit any such information. Furthermore, EPA does not believe
that an effective test can be designed to show that passive soil
can work.
Comment 315; Koppers proposes that remedial alternative GW-2, as
described in the FS report, be selected for this site. Koppers
further proposes that the selection between treatment options A
(activated carbon) and B (fluidized carbon bed) be made during
the Remedial Design phase so that the most cost effective option
meeting the discharge-criteria can be chosen.
EPA Response: EPA agrees with this proposal. The Feasibility
Study showed that the two treatment options for groundwater reme-
diation offered similar treatment for nearly identical costs.
EPA is selecting both remedies and will use pilot testing during
the Remedial Design to determine the best method.
Comment #16; Koppers feels strongly that three discharge options
be considered: discharge to Wagner Creek under NPDES criteria,
discharge to a public sewage treatment plant (POTW) under pre-
treatment criteria, and re-injection under aquifer restoration
criteria. Koppers proposes that the discharge point be selected
during the Remedial Design phase assuming approval from all
appropriate parties is obtained.
EPA Response: EPA agrees with the proposed discharge locations
but not necessarily with the degree of treatment (see next com-
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ment and response). EPA only specified in the Feasibility Study
report that treated water would be re-injected into the aquifer
with any excess water discharged offsite. Both discharge to
Wagner Creek and" a POTW are feasible. EPA prefers discharge to
Wagner Creek. However, if a potentially responsible party can
negotiate a permit with a city and if discharge to the POTW does
not violate the NPDES permit for that facility, then the POTW can
be used for discharge.
Comment 117: Koppers feels that for discharge to Wagner Creek or
a POTW, the new Organic Chemical and Plastics and Synthetic
Fibers Effluent Limitation Guidelines, Pretreatment Standards,
and New Source Performance Standards would be appropriate.
Treatment standard for re-injection would be less stringent based
upon aquifer restoration criteria.
EPA Response; EPA partially agrees with the comments about dis-
charge to Wagner Creek and a POTW. However, EPA notes that the
Texas Water Quality Standards (WQS) are revised every three
years, and if Texas promulgates a new WQS for a site contaminant,
then the discharge must comply with that new requirement. The
Texas WQS are promulgated under state law, and they are therefore
a regulation which must be complied with according to Section 121
of SARA. In addition, the Texas WQS now contain a requirement
that waters of the state be free from toxicity; this was also
identified in the Feasibility Study report as being a state
regulation with which EPA's remedy must comply. The discharge
from the treatment unit will be tested to determine if it may
cause a toxic impact in Wagner Creek. If it does, then the dis-
charge requirements for the treatment unit will be revised to
comply with the WQS.
EPA also disagrees with the statement about aquifer restoration
criteria. EPA does not know of any promulgated aquifer restora-
tion criteria, nor has Koppers presented any such criteria. EPA
is requiring in the Record of Decision that the quality of any
water re-injected into the aquifer be the same as that discharged
to Wagner Creek or a POTW. The Feasibility Study report clearly
states this.
Comment 118: Will there still be some risk to residents after
remediation?
EPA Response: EPA's selected remedy requires that yards in Car-
ver Terrace will be excavated if they may pose an increased maxi-
mum risk of cancer to the residents of that yard of greater than
3 out of 100,000. EPA's Superfund policy is to reduce the cancer
risks to less than 1 out of 10,000 at a minimum; in comparison,
the chance of an American citizen contracting cancer in his or
her lifetime is 1 chance in 3. Therefore, EPA believes that the
selected remedy will adequately protect the health of residents.
Also, EPA has evaluated other health threats (ie. liver damage)
in the "Public Health Evaluation Assessment" (PHEA) in the Feasi-
bility Study report, and found that the site contamination is not
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high enough that, even with 70 years of exposure, a resident
should show any of these health problems as a result of the site
contamination.
Comment 119: Koppers agrees with EPA about the response objec-
tives for groundwater. The EPA has suggested that removal of the
"free phase" creosote from the shallow groundwater will accomp-
lish these objectives. It is not clear what EPA means by "free
phase" creosote and as such it is uncertain whether this can be
practically accomplished. However, Koppers suggests that the
measure by which the parties determine compliance with the
response objective be flexible so to allow for operational exper-
ience to bring practicality to the decision.
EPA Response; EPA observed, during the Remedial Investigation,
the discharge of an oily substance from the aquifer into Wagner
Creek; this shows the presence of a substance which floats on
water. EPA also observed vertical migration of polynuclear aro-
matic hydrocarbons (PAHs) in areas where the groundwater gradient
is upward; this indicates the presence of a substance which sinks
in water. EPA considers both the floating substance and sinking
substance to be "free phase" creosote. Another name EPA uses for
substances of this type is "non-aqueous phase liquids" (NAPLs).
EPA believes that both phases need to be removed from the upper
aquifer to 1) prevent the continued discharge of the floating
substance into the creek and 2) prevent the continued downward
migration of sinking substances into aquifers usable as sources
of drinking water. EPA will assess the means for determining
when the free phase creosote has been effectively removed during
the Remedial Design.
Comment 320: Koppers disagrees with the EPA suggestion that the
cleanup level of 1000 ppm carcinogenic PAHs should be changed.
The level of 1000 ppm corresponds to an acceptable risk level of
lxlO~^ geometric mean concentration exposure scenario for Carver
Terrace. Use of this criteria for evaluating unsaturated soil
cleanup levels had been the basis for development of the PHEA and
the basis for the discussions between EPA and Koppers during the
past six months. Section 2.5 of the FS report reviews the major
sources of uncertainty associated with EPA's method of risk esti-
mation and site specific uncertainties such as data base bias
towards the most contaminated area of the site. Koppers did not
press the EPA on these uncertainties because we agreed with the
use of the future potential geometric mean concentration exposure
scenario and the lxlO~5 risk level. Should the EPA change the
basis upon which a soil cleanup level is developed, Koppers would
consider that an arbitrary and capricious act, and against that
possibility, Koppers reserves its full rights to re-examine all
the sources of uncertainty and exposure assumptions which the EPA
has used in development of a difference cleanup level.
EPA Response: Section 121 of the Superfund law as amended
requires EPA to select a remedy which is protective of human
health and the environment. EPA Superfund policy for accomplish-
ing this is to keep cancer risks less than 10~4 with a 10 goal
i
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and to keep non-carcinogenic exposures less than the EPA Refer-
ence Dose. In determining a remedial level, EPA considers
rational pathways in which people can become exposed, and using
these pathways, determines the contaminant concentrations which
meet the cancer and non-cancer goals stated above.
The Public Health and Environmental Assessment (PHEA) in the
Feasibility Study describes the exposure pathways EPA considered
when investigating potential threats to health at this site. For
Carver Terrace, EPA looked at exposure to soils over a 70 year
span from outside activities such as play for children and lawn
work for adults. EPA evaluated this exposure for current and
future conditions, and for average and maximum exposure. The
current condition assumed that the soil and sod barrier was still
working whereas the future condition assumed that the barrier did
not work but that organic contaminants would decay. EPA and the
Koppers Company agreed that the future condition better repre-
sented conditions in Carver Terrace over the next 10 years. The
average exposure considered exposure to Carver Terrace as a
whole, that is, it did not consider yard to yard differences in
contamination. The maximum exposure considered that some resi-
dent would become exposed to the worst concentration of all the
contaminants. Since the worst concentrations of each contaminant
occur in separate yards, EPA and the Koppers Company felt that
the maximum exposure was an over-estimate of the actual exposure
any resident could experience.
For the purposes of calculating a remedial level for soils, EPA
first reviewed the current and future scenarios and the average
and maximum exposures. EPA believes the future scenario should
be used to assess the remedial levels because it accounts for
potential failures of the temporary soil and sod barrier, and it
accounts for natural degradation of site organic contaminants.
EPA also believes the maximum exposure pathway is the most
rational one for protecting the health of residents who spend
their outside time within their yards. In interviews with local
residents on June 27-28, 1988, EPA representatives found that a
number of adults stay home to raise children; therefore, the
estimated exposure frequency for pre-school children is rational
for these residents. Also, EPA feels that 26 days per year is a
rational estimate for yard work, and that adults will work in
their yard, not someone else's. The combination of pre-school
children and adult exposures comprise 85% of the lifetime expo-
sure according to the risk assessment. In addition, some school
age children could play in their yards for 52 days out of the
year. Therefore, EPA believes that some residents may be outside
for the time estimated in the PHEA, and that a yard-specific
basis is needed to determine the remedial levels.
EPA has calculated a remedial goal of 100 ppm carcinogenic PAHs
for Carver Terrace based on a yard-specific exposure scenario
using future contaminant concentrations and methods presented in
the PHEA in the Feasibility Study. In calculating the remedial
goal, EPA included the contributions from other site -contami-
nants. EPA also accounted for additive exposures to other areas
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(creek sediments, aquifer seeps, Kennedy Sand & Gravel area) .
This remedial goal prevents against an excess lifetime increased
cancer risk of 3xlO~5. The remedial level is comparable to 200
ppm total PAHs based upon the data from the Remedial Investiga-
tion. The calculations are included in Appendix C of the Record
of Decision.
EPA notes that the PHEA discusses the areas of uncertainty in
calculating risk. The Koppers Company, in its comment, notes
these uncertainties. EPA agrees that there are many elements of
uncertainty in all risk assessments, and, for this site, that
certain of the uncertainties could be substantial. EPA has
accounted for the larger uncertainties by selecting a cancer risk
of 3x10 as a remedial goal instead of lxlO~ . The primary
factor influencing EPA in this decision is the cancer potency
factor for carcinogenic PAHs. EPA provides the following com-
ments about the uncertainty:
Sampling Error: The PHEA discussed this factor only because it
is important in assessing the health risk without remedial
action. It can be controlled during the Remedial Design by a
well planned sampling program to determine which areas need reme-
diation.
Measurement Error: The PHEA discussed this factor only because
it is important in assessing the health risk without remedial
action. It can be controlled during the Remedial Design by
assuring that the laboratory follows the standard procedures for
measuring contaminants.
Potential Toxicity: The PHEA states that the toxic contaminants
at this site have been identified, and that the uncertainty from
not identifying all toxic contaminants is small.
Selection of Pathways: The PHEA notes that all residents will
not become exposed to all areas of contamination, and that adding
up the risks from each area may over-estimate the risk. This
does not add any uncertainty in developing the remedial goal
because the exposure to residents from soils in Carver Terrace is
the primary component of the risk. Other pathways by which a
resident may become exposed to contaminants in soils will add at
most IxlO"5 to the overall risk level. Also, the PHEA notes that
some pathways could not be quantified, and that the actual risks
could be higher.
Estimation of Soil Concentrations: The PHEA states that any one
person's exposure and risk will depend on the soils they actually
contact, and this can only be assessed on a case-by-case basis.
EPA feels that, based on some residents spending most of their
outside time in their yard, the soil concentrations of each yard
reflect the exposure. Therefore, EPA feels that each yard must
be remediated to below the Carver Terrace remedial action level.
Degradation of Contaminants: The PHEA states that some organic
contaminants can naturally degrade. The risk assessment reviewed
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literature studies of PAH degradation and used the 95th percen-
tile lower-bound degradation rate. EPA notes that degradation is
a site-specific phenomenon and is based on many factors. EPA nor
Koppers had any data to determine a "correct" degradation rate
for this site. In circumstances such as these, EPA normally
assumes the worst case by using no degradation rate. However,
EPA recognized that degradation does occur in nature and used the
95th percentile of all available data which is similar to that
used by EPA to develop the cancer potency factor.
Frequency of Exposure: The PHEA states that the assumptions of
the time a resident spends in Carver Terrace and other factors
will vary between people. EPA recognizes this, but strongly
believes that the time values used in the risk assessment reflect
the time some residents may spend in his or her yard. The values
for pre-school children (180 days/year), school age children (52
days/year), and adults (26 days/year) represent reasonable values
for those homes where an adult stays home. During onsite inter-
views with residents, EPA also found that three generations lived
in some homes, and that some residents have lived in the same
area for over 60 years. From this, EPA believes that the fre-
quencies of exposures are valid for this site. EPA also notes
that the values used for soil ingestion, organic exposure through
skin, and other rate assumptions are similar to those used in
other risk assessments for Superfund sites. Therefore, EPA
believes that these values are also valid.
Dose-Response Assessment: The PHEA identifies several factors
which may cause uncertainty in determining the potency of a chem-
ical. EPA notes that two of these, animal to human extrapolation
and high to low dose extrapolation, are inherent in determining
the cancer potency factors . EPA has developed cancer potency
factors for a number of compounds including arsenic, 2,3,7,8
tetrachlorinated dibenzo-p-dioxin, and benzo(a)pyrene. These
factors have been extensively reviewed by EPA and outside
researchers; EPA stands behind these. EPA acknowledges that the
third factor, compound to compound extrapolation, adds additional
uncertainty to the risk assessment. EPA has considered all
potentially carcinogenic PAHs to be as potent as benzo(a)pyrene
because there are no cancer potency factors for the other PAHs.
EPA also recognizes that the other potentially carcinogenic PAHs
may have much lower cancer potency factors, and that benzo(a)
pyrene is on the average 13% of the carcinogenic PAHs. EPA has
accounted for this by using the 3xlO~5 cancer risk value as a
remedial goal instead of a lower value such as 1x10 which EPA
has used in other Superfund decisions for residential sites.
Risk from Multiple Compounds: The PHEA states that little infor-
mation is available about the additive effects of risks from
multiple compounds. However, EPA notes that the primary source
of health risk at this site is from the potentially carcinogenic
PAHs, and that the risks for other contaminants is only 3% of
that for potentially carcinogenic PAHs. Therefore, EPA does not
feel that this area of uncertainty affects the decision of the
remedial goal. Also, there could be synergistic or antagonistic
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effects which could make the actual risk higher or lower, but
these cannot be defined without site-specific studies.
Risk to Sensitive Populations: The PHEA states that some resi-
dents will be at greater or less risk than what is calculated due
to their specific sensitivities. Since this could justify either
a higher or lower remedial goal, and there is no data to deter-
mine how to account for this, EPA does not feel that this area of
uncertainty affects the decision of a remedial goal.
In addition to the risk assessment, EPA also consulted with the
Agency for Toxic Substance and Disease Registry (ATSDR) regarding
the remedial goal. ATSDR has previously stated in memoranda
dated January 1, 1986, and September 11, 1986, that a level of
100 ppm total PAHs is protective of human health. In assessing
this level, ATSDR considered that PAHs are known to degrade in
soils and that the potency of most PAHs is less than that for
benzo(a)pyrene. ATSDR also reviewed the remedial goal for this
site and stated in a August 26, 1988 memorandum that the goal was
also protective of human health.
Comment 321: Will the health of residents in Carver Terrace be
studied? Why haven't people been tested?
EPA Response: At present, no federal or state agency has conduc-
ted or is planning to conduct a study of residents' health. The
Agency for Toxic Substance and Disease Registry (ATSDR) is writ-
ing a health assessment, and this document will be used to deter-
mine if residents' health should be studied. If such an study is
recommended based on the site data, then factors such as skin
sensitivity can be studied.
A health study would require more than just testing people to see
if site contaminants are inside their bodies. The site contami-
nants which pose the greatest problems are the PAHs. PAHs are
also found in cigarette smoke, wood smoke, char-broiled meats,
automobile exhaust, and asphalt roads. Finding PAHs inside a
person's body would n9t show that the person has been exposed to
site contaminants.
Comment *22: When will the health assessment be completed for
this site?
EPA Response: The health assessment is presently being written
in Atlanta at the offices of the Agency for Toxic Substance and
Disease Registry (ATSDR). The report is expected to be completed
by November of 1988.
Comment t23: How has the residents' health been affected from
past exposure? What are the other health problems other than
cancer?
EPA Response: EPA conducted a risk assessment which describes
the possible threats to health; this assessment is located in
Feasibility Study report. The contaminants at the site are
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hazardous to humans because, at high concentrations, they have
caused health problems in people or laboratory animals. The risk
assessment shows that, based on the levels of contamination at
the site, that there are no immediate threats to health at this
site. There is not enough site contamination to cause non-
carcinogenic health effects, and the increased lifetime risk of
cancer is small (7 chances out of 10,000) when compared to risk
of cancer for most Americans (1 chance out of 3) . Therefore, EPA
does not believe that there have been any adverse health risks
caused by this
Comment I.2j4: There is something dangerous in the water lines.
EPA Response; EPA sampled the water lines in Carver Terrace in
1985. EPA found no contamination from site contaminants in the
water lines, nor did EPA expect to find any because the water
pressure will assure that water flows out any leaks and not into
the pipe. EPA recognizes that the drinking water may taste bad
or the pipes look bad. Texarkana gets its water from Lake
Wright-Patman; during the spring and summer algae blooms can
cause poor tasting water. Algae can also grow inside the water
lines and become trapped in faucets. Furthermore, dissolved
minerals from the lake such as calcium can be trapped in faucets.
These may be causing the aesthetic problems with the water.
Comment 325: How long does it take to see health impacts?
EPA Response: The length of time before a health effect is seen
depends on the type of contaminant, the amount of that contami-
nant, and the particular sensitivity of the person exposed. EPA
estimated in the risk assessment the potential for residents'
health to be affected by the site contaminants. With the types
and amounts of contaminants at this site and using cancer potency
factors and reference doses (EPA's factors for calculating health
impacts) , EPA calculated that there would be no adverse health
effect other than a small increase in the rate of cancer. EPA's
calculations of cancer risk used a lifetime (70 years) of expo-
sure; the risk would be lower with fewer years of exposure.
Comment 326; When EPA decided to remediate this site, was there
enough contamination to merit remediation, and was it dangerous
enough to cause serious health effects to residents?
EPA Response: This site was referred to EPA because of one soil
sample and observations of groundwater contamination. EPA added
this site to the list of Superfund sites because there could be a
potential threat to health; EPA needed a study to determine if
there was an actual threat. At some Superfund sites, 'EPA some-
times finds that there is no actual threat. After a three year
study including a risk assessment of public health, EPA found
that the primary health threat is an increased risk of cancer of
7 chances in 10,000. In comparison, the typical American has a
cancer risk of 1 chance in 3. The increased threat of cancer is
sufficient, however, tat EPA believes remediation is necessary.
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Comment *27: There are 28 people with cancer out of 350 families
located downstream along Days Creek. Is this a high number?
EPA Response; EPA does not know the specifics about the families
living downstream along Days Creek. The types of cancer and the
times at which the cancers occurred determine whether the number
is large or not. Statistically and assuming three people per
family, 350 of those people could have a cancer sometime in their
lifetime. On the other hand, if all 28 people showed a new can-
cer last year, chis number would be high.
Concerning this site, EPA's study shows no migration in ground-
water beyond roughly 500 feet from the site. Furthermore, EPA
found water quality in Wagner Creek, a tributary to Days Creek,
to be no different below the site than above the site. There-
fore, EPA does not believe that this site could be contributing
to any existing health problems downstream along Days Creek.
Comment *2B: Is it going to take another three years before we
can find out whether the area is safe for us to live in?
EPA Response; EPA conducted a risk assessment which describes
the possible threats to health; this assessment is located in the
Feasibility Study report. The study shows that, based on what
EPA has learned about the contamination at the site and what
those contaminants can do to laboratory animals, that there are
no immediate threats to health at this site. EPA will begin the
remediation at the site by designing, constructing, and operating
the remedy. The part of the remedy dealing with soils in Carver
Terrace should be completed within three years. After that time,
EPA is confident, based on the risk assessment, that there will
be no adverse long-term risks to residents' health.
Comment 429; Why don't you study people instead of laboratory
animals? People are different from white mice.
EPA Response; When EPA or scientists study the toxic effects of
chemicals, they give a laboratory animal a large amount of that
chemical. This is done because the scientist wants to see some
effect on the animal's health. The levels that people become
exposed to are much lower than that for the animal. Concerning
PAHs, the most hazardous chemicals at this site, people are also
exposed to PAHs by breathing cigarette smoke or eating char-
broiled meats. By studying people, a scientist may not be able
to measure any PAHs in the body, and if found, the scientist
could not tell if they came from the site or from smoke or meat.
Comment 430; Were we exposed by eating garden vegetables?
EPA Response; The amount of a contaminant absorbed by a plant
depends on the type of soil, contaminant, plant, and part of
plant which is edible. Also, any soil adhering to a root vege-
table could contain contaminants. At this site, the primary
contaminants, PAHs, should not be absorbed because PAHs have a
high organic carbon partition factor which means that PAHs are
A-13
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tightly bound to soils. EPA feels that the greatest exposure
from eating garden produce would be the soils adhering to the
skin of root vegetables. Residents would have greatly reduced
any exposure by washing the produce before eating it.
Comment 331; EPA is just studying this site to determine what
happens to people's health while the remediation is going on.
Are the residents of Carver Terrace being used as guinea pigs?
EPA Response: EPA is proceeding with the remediation of this
site in full confidence that residents' health is not affected by
site contamination. EPA has completed a risk assessment to
determine the possible threats to health. This assessment is
contained in the Feasibility Study. This assessment shows that,
based on what EPA has learned about the contamination and how
these contaminants affect laboratory animals, that there are no
immediate threats to health at the site. A person needs up to 70
years of exposure to see a risk of cancer of 7 chances in 10,000.
This is in comparison to the typical American's risk of cancer of
1 chance out of 3. EPA's policy is to remediate Superfund sites
so that the cancer risk is less than 1 chance in 10,000 and as
close to 1 chance in a million as possible. Therefore, EPA will
continue to remediate the site.
Comment 3.32: What yards will be tested. Will EPA test around
the edges of the houses where some contamination may be?
EPA Response; EPA determined the areas of contamination during
the Remedial Investigation. There are two areas in Carver Ter-
race. One is along the south side of West Third Street. The
other runs along Fannin Street, starting from the east side at
the intersection with West Third Street and ending on the west
side at the intersection with Travis Street. EPA will resample
the yards within these areas to determine which yards contain
contaminants in sufficient amounts to need remediation. EPA will
sample inhabited and vacant lots and can sample along the house.
Comment 333; Who is going to be monitoring the neighborhood
during future work, and who do we go to talk to?
EPA Response: EPA will assign a person to the site during reme-
diation to conduct air monitoring and supervise all activities.
If a potentially responsible party (PRP) offers to construct the
remedy, then EPA will also require that the PRP monitor the air
under EPA's supervision.
Any citizen can call EPA in Dallas at (214) 655-6735 to discuss
the site, report any problems, or ask any questions.' In addi-
tion, any citizen can talk with EPA's onsite representative dur-
ing remediation.
Comment 134: Do you on the panel tonight have anything to do
with Koppers? Who does the panel tonight answer to?
A-14
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EPA Response: The members of the panel during the public meeting
were representatives of EPA, a federal agency called the Agency
for Toxic Substance and Disease Registry (ATSDR), and the Texas
Department of Health (TDK). Each member reports to their office
heads in Dallas (EPA), Atlanta (ATSDR), and Austin (TDK).
Comment 335; Someone is offering me $4800 to release Koppers
from responsibility and to pay legal costs for children if they
sue Koppers. Who is this? If we sign this settlement, does that
mean we will not be paid for our house? If we sign it, will we
be giving up our house?
EPA Response: EPA understands that the Koppers company is trying
to settle a lawsuit. However, since EPA was not a party in this
lawsuit nor has EPA filed a lawsuit against Koppers, EPA does not
know any of the terms of the settlement. Local citizens should
consult an attorney regarding the settlement.
Comment |3_6; I was told by Koppers that the statute of limita-
tions to sue Koppers had run out. Is this true?
EPA Response; EPA does not know what law Koppers is referring to
or under whick laws previous lawsuits were filed. EPA suggests
that any citizen contact an attorney to explain this and any
particulars about the lawsuit. Under the Superfund law, EPA has
the right to sue any person or company who may be responsible
under the law; EPA has up to three years after the site is
remediated to file suit.
Comment 137: Why spend $8 million on remediating the site when
EPA could buy the houses for less than that? Will you purchase
my house? I was told that if something happened and the houses
were condemned, that the Government would pay for our houses.
EPA Response: The Superfund law requires EPA to remediate a site
with a preference to permanently destroying the contamination.
That means that EPA must destroy or remove contaminants from
Superfund sites regardless of whether there are people living on
the sites. If EPA actually purchased houses, that cost would be
in addition to the costs of remediating the contamination. EPA
cannot just buy houses and walk away from a site.
At this site, EPA will not buy any house. EPA can clean the site
contaminants to below health-threatening levels. This site, as
discussed earlier, does not pose a short-term health risk which
would require immediate relocation or purchase of houses.
Comment 138: Is there anything in the Superfund law that says
EPA can't make Koppers pay people for their property?
EPA Response: The Superfund law gives EPA the authority only to
order responsible parties to clean a site or to recover the costs
of cleaning a site when EPA does the work. If EPA selects a
remedy which requires property to be bought, only then can EPA
require a responsible party to buy that property.
A-15
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Comment 339; My property value has gone down; could I be compen-
sated for this? What will be our resale value on property after
you remediate it?
EPA Response: In conducting its environmental mandate, EPA must
balance a large number of factors before determining the best
approach to addressing problems at Superfund sites. The Super-
fund Amendments and Reauthorization Act (SARA) specifies that EPA
shall "... select a remedial action that is protective of human
health and the environment ..." The statute also states that EPA
shall "... select appropriate remedial actions determined to be
necessary to be carried out ... which provide for cost-effective
response." These laws are developed by Congress and EPA must use
them as a guide in conducting its business.
EPA believes that the selected remedy at the site complies, to
the maximum extent practicable, with the provisions of the Super-
fund law. The first priority of the Agency is the protection of
human health and the environment and the selected remedy serves
this purpose very well.
Selecting solutions which account for local property values is
outside the jurisdiction of EPA. Local residents have the State
courts available to them to resolve these issues, or they can
request that their State government intervene on their behalf.
State governments have the opportunity to request for and pay the
additional costs attributed to meeting any such standard they may
deem necessary. This could include a request to purchase pro-
perty at a Superfund site. Additionally, the state would then
become a signatory to the Consent Decree and actively participate
in negotiations, the remedial design and remedial action.
Comment J40; Has EPA ever condemned houses on Superfund sites?
What did EPA do for the residents?
EPA Response; Under section 300.70(e) of the National Contin-
gency Plan, EPA is authorized to permanently relocate residents,
businesses and community facilities where it is determined that
human health is in danger and that relocation would be cost-
effective and environmentally preferable to other remedial
responses. EPA, in responding to previous comments, believes
that human health is not in danger at this site nor will be after
remediation, that the cost of relocation would be on top of the
remediation cost and thereby not be cost-effective, and that it
is preferable to remediate the contaminants rather than to leave
them in place.
EPA has relocated residents at eight Superfund sites. Existing
health problems required relocation at two sites; construction
needs required relocation at the other six sites. The following
is a list of each of those decisions containing EPA's actions and
reasons for the relocation:
Love Canal: EPA relocated residents who were or might be exposed
to health-threatening levels. Some residents had health problems
which were definitely attributed to site contaminants.
A-16
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Lansdown Radiation: EPA relocated residents who were exposed to
radiation from radium above safe levels.
Mountain View/Globe: EPA relocated residents whose houses were
built on asbestos mine tailings (waste ore). These wastes had to
be controlled by constructing a cap (cover) over the tailings.
The cap would disrupt normal residential activities.
Hipps Road: EPA relocated four families whose houses were built
over a landfill which was leaking. EPA needed to destroy those
houses to remove the leaking wastes.
Times Beach: EPA relocated residents living in a town contami-
nated with dioxin wastes. The remediation would take a long time
and house interiors needed to be cleaned.
Minker/Stout/Romaine: EPA relocated residents living in a town
contaminated with dioxin wastes. The remediation would take a
long time and house interiors needed to be cleaned.
United Creosoting: EPA will relocate six families whose houses
where built over a leaking creosote wastewater lagoon. EPA needs
to excavate the lagoon.
Bayou Bonfuca: EPA will relocate some families whose houses are
located in an area where EPA needs to excavate a ditch.
Comment f41: A man came to the neighborhood to ask whether Gov-
ernment money was used to buy the houses, or whether the houses
were purchased in another way.
EPA Response: EPA does not know who this person was. EPA does
not believe it was an EPA employee because this information is
not needed to determine what method EPA will use to remediate a
Superfund site.
Comment $42; The initial response action did not cover the con-
taminated soils with 6-inches of soil. The soil cover during the
initial removal action did not work. A rain three weeks later
washed the soil away. The water also contaminated the soils.
The soil is washing off or sinking into the ground.
EPA Response; EPA had the Koppers Company install a soil and sod
barrier in several yards in Carver Terrace in 1985. The goal of
this action was to protect local residents from contacting con-
taminated soils during the time EPA was studying the site; this
was explained to local residents during public meetings held in
Carver Terrace in 1985. EPA supervised the installation to
assure that enough sod was installed to keep soil from blowing
away. In some yards, additional soil was added to keep the sod
healthy. The depth of soil and sod ranged from 2 to 6 inches.
EPA's representative also inspected the yards after installation
to assure that the work was correctly done. Finally, EPA did not
release Koppers from its responsibility to maintain the sod
barrier until EPA was sure that the sod was established.
A-17
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Comment *43: When EPA put soil over some yards in 1985, why did
EPA ask us if we wanted the soil, then only laid the soil in
certain areas?
EPA Response: When EPA installed the soil and sod in 1985, EPA
did not know the location of all the contaminated areas. There-
fore, EPA asked local residents about what they may have seen in
their yards. EPA then sampled yards where the residents allowed
EPA access and EPA suspected contamination. Based on the results
from the sampling, EPA determined those yards with soil contami-
nation which needed the soil and sod.
Comment f44; Who put the soil down on the yards on West Third
Street?
EPA Response: EPA determined in 1985, after testing and observa-
tions of the soil, that soil covered by sod needed to be laid
down on several yards. The soil and sod was intended to be a
temporary way to keep residents from coming into contact with
contaminants while EPA studied the site to determine a remedy.
Under the Superfund law, EPA is required to ask a potentially
responsible party to take any action like this before EPA can
proceed. The Koppers Company offered to do this work for EPA.
This work was done by Koppers under the terms of an Administra-
tive Order on Concent and under EPA supervision.
Comment 145; I would like some information about the flooding
problems in the neighborhood.
EPA Response: EPA understands that Carver Terrace is located in
a flood plain, and that rainfall runoff collects because there is
no stormwater drainage out of the area. EPA will take action to
improve the drainage from Kennedy Sand & Gravel to reduce drain-
age from that property into Carver Terrace. EPA can also manage
any remedial activity requiring excavation so that exposed con-
taminants are not washed out during rainfalls. However, EPA
cannot completely solve the drainage problems in Carver Terrace
because it does not have the authority to do so under the Super-
fund law. EPA cannot take actions to eliminate flooding problems
which are not required under the remedial action to address
health and environmental concerns.
Comment 146: After it rains, there is a crust on the ground. My
child plays in the crusts. Is this direct contact?
EPA Response: EPA does not know what this crust consists of. If
site contaminants are in that crust, then the child is probably
exposed to the contaminants if the child puts objects into his or
her mouth or eats without washing hands.
Comment 147: In my yard, these is a black tar a foot below the
surface. Is this what you are calling the toxic?
EPA Response: The black tar is probably related to the old creo-
soting activities. The tars do contain the same hazardous sub-
stances which EPA is remediating. However, solid tars do not
A-18
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pose the same hazard because the hazardous substances are tied up
with the tars in the sane way as in asphalt roads.
Comment ~48: Grass won't grow on the site.
EPA Response: EPA recognizes that the contaminants on the site
can interfere with grass growth. EPA expects that remediation
will remove any contaminants which may affect the grass. EPA has
observed this at other old wood preserving sites.
Comment t49_: What about the other Super fund site and Kerr-McGee
which drains into the Days Creek area?
EPA Response: The other Superfund site in Texarkana is called
Texarkana Wood Preserving and is located less than a mile to the
east of Carver Terrace. The Texas Water Commission is conducting
a remedial investigation study which has just begun. Kerr-McGee
is an active facility which is permitted to dispose of hazardous
waste. That facility is in the process of closing down its dis-
posal areas and is also cleaning the groundwater under the dis-
posal areas. EPA and the Texas Water Commission are supervising
these activities.
Comment 350: Can EPA state that they will not find something
later that will require the houses to be condemned and the resi-
dents to leave the area?
EPA Response: Based on the extensive data collected during the
Remedial Investigation, EPA knows where the contamination is and
how to remediate the contamination to protect the health of local
residents. However, EPA cannot guarantee what will happen five
or ten years in the future. But, from what EPA knows about these
contaminants today, EPA sees no reason for condemning houses
after remediation is completed.
Comment a51: If you were a resident of Carver Terrace, would you
want to continue to live in that neighborhood?
EPA Response; EPA is confident that, after remediation, there
will be no health threat at this site posed by site contaminants.
Comment 452: I heard this was going to be a commercial area.
EPA Response: EPA does not know of any intention to develop
Carver Terrace as a commercial area. EPA does consider Kennedy
Sand & Gravel to be a commercial area because there are two large
pits in the land and the Texarkana flood plain law discourages
further residential development within this floodplain.
Comment 153; Will this (the July 20, 1988, meeting) be the last
informative meeting that you are going to hold?
EPA Response: The public meeting on July 20, 1988, is the last
meeting before EPA selects the remedy. However, EPA will con-
tinue to hold informational meetings as the design and construe-
tion of the remedy progresses.
A-19
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APPENDIX B
APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
-------
APPENDIX B: APPLICABLE OR RELEVANT AND APPROPRIATE REQUIRMENTS
Section 121(d)(2) of CERCLA as amended in 1986 by SARA requires
that the selected remedy attain requirements adopted under Fed-
eral and state environmental laws. These requirements are called
"ARARs" which means "applicable or relevant and appropriate
requirements".
The Feasibility Study for the Koppers Texarkana site included a
review of these laws, and identified those which could be ARARs
based on the types of wastes at the site, the types of remedial
actions contemplated, and the site location. This appendix lists
all the laws which the Feasibility Study identified as potential
ARARs for this site, and indicates whether each of the final
remedial alternatives can comply with the laws. The appendix
also includes the laws which the Feasibility Study did not iden-
tify as potential ARARs but which EPA now believes are ARARs.
SAFE DRINKING WATER ACT
National Primary Drinking Water Standards: Establishes health
based standards for public water systems (maximum contaminant
levels); an ARAR for groundwater alternatives because the lower
aquifer (stratum III) is categorized as Class IIB (potential
water supply).
National Secondary Drinking Water Standards: Establishes
aesthetic based standards for public water systems (secondary
maximum contaminant levels); an ARAR for groundwater alterna-
tives because the lower aquifer is categorized as Class IIB.
Maximum Contaminant Level Goals: Establishes drinking water
quality goals set at levels of no known or anticipated adverse
health effects, with an adequate margin of safety; not an ARAR
but a factor to be considered for those contaminants where the
Maximum Contaminant Levels have yet to be promulgated.
Underground Injection Control Regulations: Provides for protec-
tion of underground sources of drinking water; not an ARAR for
groundwater alternatives because wells will not be used to re-
inject treated groundwater.
CLEAN WATER ACT
Water Quality Criteria: Sets criteria for water quality based on
toxicity to aquatic organisms and human health; an ARAR for
disposal of those compounds for which there are no state water
quality standards; applies to the discharge after mixing with
Wagner Creek water.
B-l
-------
National Pollutant Discharge Elimination System: Requires treat-
ment performance for the discharge of pollutants for any point
source into waters of the United States; an ARAR for disposal
of water into Wagner Creek.
National Pretreatment Standards: Sets standards to control
pollutants which pass through or interfere with treatment pro-
cesses in public treatment works or which may contaminate sew-
age sludge; an ARAR because one possible disposal option from
the groundwater treatment system is to a local sewage treatment
plant.
OCCUPATIONAL SAFETY AND HEALTH ACT: Regulates worker health and
safety; an ARAR for all site activities.
HAZARDOUS MATERIALS TRANSPORTATION ACT: Regulates transportation
of hazardous materials; an ARAR for the offsite transport of
recovered oil and creosote for burning, offsite transport of
soil in the landfill and incineration alternatives, and offsite
transport of drill cuttings in the no action, cap, and in-situ
bioremediation alternatives.
EXECUTIVE ORDER ON PROTECTION OF WETLANDS: Requires Federal agen-
cies to avoid to the extent possible, the adverse impacts asso-
ciated with the destruction, or loss of wetlands and to avoid
support of new construction in wetlands if a practical alterna-
tive exists; not an ARAR because the gravel pits do not consti-
tute wetlands.
EXECUTIVE ORDER ON FLOODPLAIN MANAGEMENT: Requires Federal agen-
cies to evaluate the potential effects of actions they may take
in a floodplain to avoid, to the extent possible, the adverse
impacts associated with direct and indirect development of a
floodplain; an ARAR for all alternatives because the site is
within the 100 year floodplain.
ENDANGERED SPECIES ACT: Requires action to conserve endangered
species within critical habitats upon which the species depend,
requires consultation with the Department of Interior.
SOLID WASTE DISPOSAL ACT
Standards Applicable to Generators of Hazardous Waste: Estab-
lishes standards for generators of hazardous wastes; an ARAR
for all alternatives including No Action.
Standards Applicable to Transporters of Hazardous Waste: Estab-
lishes standards which apply to transporters of hazardous waste
within the U.S. if the transportation requires a manifest under
B-2
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40 C.F.R. Part 262; an ARAR for the offsite transport of
recovered oil and creosote generated from the groundwater
treatment system, the offsite transport of soils in the
landfill and incineration alternatives, and offsite transport
of drill cuttings in the no action, cap, and in-situ bioremed-
iation alternatives.
Standards for Owners and Operators of Hazardous Waste Treatment,
Storage, and Disposal Facilities: Establishes minimum national
standards which define the acceptable management of hazardous
wastes for owners and operators of facilities which treat,
store or dispose of hazardous wastes. Each subpart follows:
General Facility Standards (Subpart B): Sets siting require-
ments for floodplains; an ARAR for treatment units located at
Kennedy Sand & Gravel (in the floodplain).
Releases from Solid Waste Management Units (Subpart F): Sets
groundwater remediation levels; an ARAR for groundwater
alternatives.
Closure and Post-Closure (Subpart G): Sets standards for main-
tenance of disposal sites; an ARAR only soil for alternatives
leaving treated soils at the site.
Use and Management of Containers (Subpart I): Sets require-
ments for storage of wastes in containers; not an ARAR
because containers will not be used in any alternative.
Tanks (Subpart J): Sets requirements for storage of wastes in
tanks; an ARAR for the groundwater treatment system.
Surface Impoundments (Subpart K): Sets requirements for dis-
posal or treatment of wastes in surface impoundments; not an
ARAR because no alternative uses surface impoundments.
Waste Piles (Subpart L): Sets requirements for storing and
treating wastes in piles; an ARAR for soil alternatives which
store wastes in piles prior to disposal or treatment.
Land Treatment (Subpart M): Sets requirements for treatment of
wastes by placing them in land; not an ARAR because no
alternative uses this method.
Landfills (Subpart N): Sets requirements for disposal of
wastes in landfills; not an ARAR only because no alternative
creates a new landfill.
Incinerators (Subpart 0): Sets requirements for incineration
of wastes; an ARAR for the soil incineration alternatives and
the groundwater alternatives if the recovered creosote will
be incinerated.
Land Disposal Restrictions: Establishes allowable concentration
levels for burial of hazardous wastes; an ARAR for soil alter-
B-3
-------
natives but only for the soils (including the drill cuttings)
which may have become contaminated by leachate from the old
wastewater lagoon; most soils to be remediated were not contam-
inated with a RCRA listed waste (K001 sludge or U051 creosote)
and are not subject to these restrictions; an ARAR for ground-
water alternatives for the incineration or recycling of the
creosote collected from the groundwater.
TEXAS DEPARTMENT OF HEALTH
Allowable Limits of Metals in Drinking Water: Sets health-based
standards for public water systems; these set remedial levels
for groundwater alternatives.
Location of Wells used for Drinking Water Supplies: Restricts
placement of drinking water wells; restricts location of solid
waste disposal sites; an ARAR for groundwater alternatives
because remediation requires a long time for completion.
TEXAS WATER COMMISSION
Water Quality Standards for Surface Waters: Prohibits point
source discharges which cause toxicity in natural streams and
sets maximum levels for selected contaminants; an ARAR for
discharge of treated groundwater into Wagner Creek; applies to
the discharge after mixing with Wagner Creek.
TEXAS AIR CONTROL BOARD
Prohibition of Air Contaminants which Adversely Effect Human
Health: Health-based standards for air; only an ARAR for those
alternatives which disturb the soil and may cause a release.
Control of Air Pollution from Visible Emissions and Particulate
Matter: Maximum allowable levels of particulates in air; an ARAR
for incinerators.
Storage of Volatile Organic Compounds: Regulates handling of
tanks containing volatiles; an ARAR for the groundwater
treatment system if recovered creosote is stored in a tank.
Oil/Water Separators: Controls volatile emissions from separ-
ators; an ARAR for the groundwater treatment system.
Vacuum Producing Systems: Requires incineration of emmissions
from vacuum producing systems; not an ARAR for this groundwater
collection and treatment system.
B-4
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Alternative #1:
Alternative #2:
Alternative #3:
Alternative #4:
Alternative #5:
Alternative #6:
Alternative $7:
Alternative #8:
Alternative #9:
Alternative #10.
LIST OF REMEDIAL ALTERNATIVES
No Action
Capping
In Situ Bioremediation
Mechanical Soil Washing
Onsite Incineration
Offsite Incineration
Offsite Landfill
Passive Soil Washing
Groundwater Collection; Physical Separation,
Filtration, and Activated Carbon Treatment
Groundwater Collection; Physical Separation,
Filtration, and Fluidized Carbon Bed Treatment
NOTE: Alternatives 9 and 10 are actually the groundwater
parts of alternatives 2 through 8. They are
discussed separately within this appendix to help
distinguish the ARARs pertaining to groundwater
actions from the ARARs pertaining to soil actions.
B-5
-------
FEDERAL ARARS
St3no&rof K c cj u J r c ffi
-------
FEDERAL A It A R S continued
| Remedial Alternative
I
1 2 3 | 4 | 5 | 6 | 7 | 3
Standard, Requirement,
Criteria, or Limitation
10
SOL ID WASTE 01SPOSAL ACT
Standards for Generators of Haz-
ardous Uaste (40 CFR Part 262}
Standards for Transporters of Haz-
ardous Uaste (40 CFR Part 263)
Standards for Owners and Operators
of Hazardous Uaste Treatment,
Storage, and Disposal Facilities:
General Facility Standards
(40 CFR Part 264 8)
Releases from Solid Uaste Management
Units (40 CFR Part 264 F )
Closure and Post-Closure
(40 CFR Part 264 G)
Use of Containers
(40 CFR Part 264 I)
Tanks
(40 CFR Part 264 J)
Surface Impoundments
(40 CFR Part 264 K)
Uaste Piles
(40 CFR Part 264 L)
Land Treatment
(40 CFR Part 264 H )
Landfills
(40 CFR Part 264 N)
Incinerators
(40 CFR Part 264 0)
Land Disposal Restrictions
(40 CFR Part 268)
, A
A A
A = ARAR; 0 * other factor to be considered
B-7
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STATE OF TEXAS ARABS
I Remedial Alternative
Promulgated Standard. Requirement, |
Criteria, or Limitation
DEPARTMENT OF HEALTH
Allowable Limits of Metals in
Drinking Water
Location of Welli ustd for
Drinking Water Supplies
WATER COMM I SS I ON
Water Quality Standards for
Surface Waters
AIR CONTROL BOARD
Prohibition of Air Contaminants
that Adversely Effect Human Health
Control of Air Pollution from Visi-
ible Emissions and Particulates
Storage of Volatile Organics
Oil/Water Separators
Vacuum Producing Systems
1 1
t
A
A
A
2
. .
...
3
I ...
1
4
1
1 5
i .
I
6
1
A
7
t
A
8
t
9
A
A
A
A
A
A
1 0
| ....
A
A
A
....
A
A
A
A » ARAR; 0 * other factor to be considered
8-8
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APPENDIX C
RISK CALCULATIONS
-------
Potential Risks for Carver Terrace Soils
No Action Alternative
( a )
Cont am i nant
Carcinogen*
PCP
D i o x i n E q u i
Arsenic
C h r om i urn
Coppe r
Lead
Mercury
Zinc
TOTALS
C on t am i nant
Carcinogeni
PCP
0 i ox i n E qu i
A r sen i c
C h r om i um
Copper
Lead
Mercury
Zinc
TOTALS
M a x i mum
Concentrat i
( mg/ kg so i
c PAHs(b) 20
on
I )
21
17
valents(6> 0.000767
53.
57
1
35
.5
01
298
0.355
33
Average
Concentrat i
( mg/ kg so i
c PAHs(b) 49
1 .
70
on
I )
. 7
35
velents(b) 0.0000077
2.
3.
2.
13.
0.
29
77
94
57
54
18
. 9
Total
Lifetime
Intake
(mg/kg/day )
5 .
6.
6.
1 .
1 .
3.
9.
1 .
1 .
L i
(mg/k
1 .
5 .
6 .
1 .
2.
3.
1 .
5 .
4 .
21E
15E
55E
77E
91E
35E
88E
18E
12E
To
f et
Int
-05
-06
- 1 1
-05
-05
-05
-05
-07
-03
tal
i me
ake
g/day)
28E
21E
59E
32E
70E
24E
40E
97E
72E
-06
-07
- 13
-06
-06
-06
-05
-08
-05
Hazard
Index
S S — — — ~
2E
4E
9E
7E
8E
5E
8E
H az
-04
-03
-04
-02
-05
-03
-02
ard
Index
2E
5E
9E
1E
4E
2E
S — 2
1 £
-05
-04
-05
•02
-05
• 04
3 5 —
-02
Excess
Max i mum
Lifetime
Cancer
Risk
s s s s s ~ as
6E-04
IE-OS
3E-05
— — — 3S3S 3
6E - 04
Excess
Average
Lifetime
Cancer
Risk
1 E -05
1 E - 07
2E -06
— S — ~ S — S —
2E-05
(a)
(b)
Exposure reflects the scenario in the FS report
called "Future Carver Terrace".
Concentrations reflect present levels;
degradation reflected in intake calculations.
C- 1
-------
Potential Risks for Kennedy Sand & Gravel Soils (Commercial Use)
No Action Alternative
( a )
Contaminant
M a x i mum
Concentrat i on
(mg/kg soil)
Carcinogenic PAHs
PCP
Arsenic
Chromium
Copper
Zinc
TOTALS
221
0.8
14.9
12
9.7
35.2
Total
Lifetime
Intake
(mg/kg/day)
4.22E-07
2. 14E-08
3.64E-07
2.93E-07
2.36E-07
8.60E-07
Hazard
Index
7E-07
6E-05
6E-06
4E-06
= 33333
7E-05
Excess
M a x i mum
Li f e t i me
Cancer
Risk
5E -06
5E -07
5E -06
Contami nant
Carcinogenic
PCP
A r sen i c
C h r om i urn
Copper
Z i nc
TOTALS
Average
Concentrat
(mg/kg so
i
i
PAHs(b) 88
1
0
4
9
33
on
I )
.2
.8
.9
12
. 7
.6
L
(mg/
1
2
3
2
2
8
Tot
i f e t i
1 n t a
a I
me
ke
kg/day)
.69E-
. 14E-
.64E-
.93E-
.36E-
. 21E -
07
08
07
07
07
07
E
xc
Aver
H a z
ard
Index
7E
6E
6E
4E
7E
-07
-05
-06
-06
•05
L i f
C
e t
ess
age
i me
a nc e r
R
2E
5E
2E
i sk
-06
-07
-06
(a)
(b)
Exposure reflects the scenario in the FS report
called "Current Kennedy Sand & Gravel".
Concentrations reflect present levels;
degradation reflected in intake calculations.
C-2
-------
Potential Risks for Wagner Creek Seeps
No Action Atterntative
Contami nant
Carcinogenic PAHs
Ethyl benzene
Toluene
Xy I enes
A r s en i c
Chromium
Copper
Lead
Mercury
Zinc
Maximum
Concentration
(mg/kg soil)
74
5.4
2.9
5 .6
1
1
2.5
12
0.12
22
L i
-------
Potential Risks for Wagner Creek Sediments
No Action Alterntative
(a)
Excess
Contami nant
Carcinogenic
Benzene
Toluene
Xy I ene
A r s en i c
Ch r am i urn
Copper
Lead
Mercury
Zinc
TOTALS
M a x i mum
Concentrat i on
(mg/kg soil)
PAHs(b) 17.8
0.021
0.039
0.17
10
62
7.5
160
0.9
365
L
(mg/
6
1
2
9
5
3
3
8
4
1
To
i f *t
I nt
tal
i me
ake
kg/day)
.96E
. 15E
. 13E
.30E
.COE
. 10E
.73E
.OOE
.50E
.82E
-08
-09
-09
-09
-07
-06
-07
•06
-08
-05
Maximum
H aza
rd
Index
======
7E-
9E-
6E-
1E-
6E-
3E-
9E -
6E-
09
07
04
05
03
05
05
03
L i f e t i
me
Cancer
R i
= = S = 5 =
8E-
6E-
8E-
S 3 X S S 3
2E-
sk
07
1 1
07
35 S
06
Excess
Total
Contaminant
Carcinogenic
Benzene
Toluene
Xy 1 ene
Arsenic
C h r oiti i urn
Copper
Lead
Mercury
2 i nc
============
TOTALS
Average
Concentrat i on
(mg/kg soil)
PAHs
-------
Potential Risks for Groundwat«r Users
No Action Alterntative
Excess
C on t am i nan t
Carcinogenic P A H s
Benzene
Toluene
Ethyl benzene
Xy I ene
Arsenic
Ch r om i urn
Copper
Lead
Zinc
TOTALS
M a x i mum
Concentration
(ug/l water)
8) 23.8
700
2100
1900
2900
430
270
149
60
18000
I
To
i f et
t a I
i me
Intake
(mg/
6
2
6
5
8
1
7
4
1
5
kg/day)
.80E
.OOE
.OOE
.43E
.29E
.23E
.71E
.26E
.71E
. 14E
-04
-02
-02
-02
-02
-02
-03
-03
-03
-01
Maximum
Hazard
I ndex
0.
0.
8.
1 .
0.
1 .
2.
1 4 .
6
2
3
5
1
2
4
4
L i f e t i
Cane
R i
8E-
1 E -
2E-
3E-
me
e r
sk
03
03
02
02
( a )
Concentrations reflect maximum solubility limits;
field data shows non-aqueous phase liquids
C-5
-------
Summary of Potent,.I Health R isks at the Site
Mo Action Alterntative
Excess Li fetime Excess U fetime
Health Hazards Cancer Risks
Max Avg "a* Avg
Carver Terrace Residents:
Carver Terrace 8E-02 1E-02 6E-04 2E-05
Kennedy Sand I Gravel 7E-05 7E-05 2E-06 2E-06
Ditch Sediments 6E-04 6E-04 1E-06 1E-06
Aquifer Seeps 7E-09 7E-09 1E-08 1E-08
SS3X3XSXXXXX3SXSX3XXX X * Z 3 X X = X X X SXX = 3 S S = S =
Totals 8E-02 1E-02 6E-04 2E-05
Groundwater Users 14.4 3E-02
Utility workers 2E-06 1E-07
NOTES: Exposures and risks for pathways outside a
resident's yard (seeps, sediments, and Kennedy
Sand I Gravel) are based on the average scenario
because the exposure in these areas is random.
The average exposure and risk to seeps is assumed
to be equal to the maximum exposure and risk.
C-6
-------
Potential Risks for Carver Terrace Soils
Selected Alterntaive
( a )
Maximum
Concentrat i on
Contaminant (mg/kg soil)
Carcinogenic PAHs
PCP
Dioxin Equivalents
Arsenic
Ch r om i urn
Copper
Lead
Mercury
Z i nc
100
17
0.0000077
3.3
18
27
106
0.355
552
L
( mg/
2
6
6
1
5
8
3
1
1
To
i f et
I nt
t a I
i me
ake
kg/day)
.58E
. 15E
.59E
.57E
.98E
. 99E
.51E
. 18E
.84E
-06
-06
-13
-06
•06
-06
-05
-07
-04
Hazard
Index
2E
IE
2E
3E
8E
9E
•04
-03
-04
•02
-05
-04
Excess
Max i mum
Lifetime
Cancer
Risk
3E-05
1 E-07
2E-06
TOTALS
3E-02
3E-05
Contami nant
C a r c i
PCP
0 i o x i
A r s en
Ch rom
Coppe
Lead
n og en i
n Equ i
1 C
i urn
r
Mercury
Z i nc
= = = = =
======
Average
Concentrat i
(mg/kg so i
C PAHs(b> 7
1 .
valents(b) 0.00000
2
3
2
12
0.
3
=======
on
I )
.8
35
77
.7
.9
.6
.9
18
. 4
L
( mg /
2
5
6
1
2
3
1
5
5
To
i f et
I nt
tal
i me
ake
kg/day)
.01E
.21E
.59E
.29E
.70E
.24E
.33E
.97E
.37E
-07
-07
- 13
-06
-06
-06
-05
-08
-05
TOTALS
Ha
I
z
ard
nde x
2E
5
E
9E
1
4
3
= =
1
E
E
E
=
E
-05
-04
-05
-02
- 05
-05
= = =
-02
Excess
Average
L i f e t i me
Cancer
Risk
— 3SS 3SSS
2E-06
1E -07
2E-06
========
4E - 06
(a)
(b)
Exposure reflects the scenario in the FS report
called "Future Carver Terrace" with concentrations
from the area where carcinogenic PAHs < 100 ppm.
Concentrations reflect present levels;
degradation reflected in intake calculations.
C-7
-------
Potential Risks for Groundwater Users
Selected A It ernt at i ve
Contaffli nan t
SSS»»XS*3SSSS33 = =
Carcinogenic P A H s
Benzene
Toluene
Ethyl benzene
Xy I ene
Arsenic
Ch r om i urn
C opper
Lead
Zinc
M a x i mum
Concentration
(ug/l water)
nd(8)
36(b)
3(b)
J7(b)
25(b)
nd(-)
5(b)
n(b)
nd<§)
5600(b)
Total
Lifetime
Intake
( m g / k a / d a y )
2.86E-06
1 .03E-03
8.57E-05
1 .05E-03
7. 14E-04
2 .86E-06
1 .43E-04
3.71E-04
2.86E-06
1 . 60E - 01
Hazard
Index
= S S S X S
<0.01
0.01
0 . 04
0.03
0.01
<0.01
0. 76
0.85
Excess
Max i mum
L i f e t i m e
Cancer
Risk
= = 5 = = = 5S
3E-05
5E-05
4E-06
8E - 05
TOTALS
8) Mot detected at normal laboratory procedures (use 0.1 ug/l)
Based on concentrations in areas without free phase creosote
C-8
-------
Summary of Potential Health Risks at the Site
Selected Alterntative
Excess Lifetime
Health Hazards
Excess Lifetime
Cancer Risks
Max
Av9
Max
Avg
Carver Terrace Residents:
Carver Terrace
Kennedy Sand I Gravel
Ditch Sediments
Aquifer Seeps
Totals
Groundwater Users
Utility Workers
SE-
7E-
6E-
7E-
8E-
0.
2E-
02
05
04
09
02
85
06
1E
7E
6E
7E
1E
-02
-05
-04
•09
-02
3E
2E
1E
1E
= 2
3E
8E
IE
-05
-06
-06
-08
3 = X
-05
-05
-07
4E
2E
1E
1E
= =
7E
-06
-06
-06
-08
S = =
-06
NOTES: Exposures and risks for pathways outside a
resident's yard (seeps, sediments, and Kennedy
Sand & Gravel) are based on the average scenario
because the exposure in these areas is random.
The average exposure and risk to seeps is assumed
to be equal to the maximum exposure and risk.
Exposure reflects the scenario in the FS report
called "Future Carver Terrace" with concentrations
from the area where carcinogenic PAHs < 100 ppm.
C-9
-------
APPENDIX D
STATE OF TEXAS CONCURRENCE
-------
TEXAS WATER COMMISSION
HtJ. J. Wynne, III, Chairman wr"i'"'VV\ J. D. Head, General Counsel
Paul Hopkins, Commissioner f\jf( r\ gj'j Michael E. Field, Chief Examiner
John O. Houchins, Commissioner ^k^r^r Karen A. Phillips, Chief Clerk
f ^"~="J^
Allen Beinke, Executive Director
September 27, 1988
Allyn M. Davis, Ph.D., Director ^
Hazardous Waste Management Division ^
U.S.Environmental Protection Agency -^
Region VI
1445 Ross Avenue
Dallas, Texas 75202-2733
Re: Koppers Texarkana Superfund Site
Draft Record of Decision
Dear Dr. Davis:
We have reviewed the proposed Record of Decision (ROD) for the
Koppers Texarkana Site. We have no objection to the selected
remedy of mechanical soil washing and groundwater treatment
(Alternative 4) as described in the draft ROD of
September 20, 1988.
It is our understanding that the soils excavated from the Carver
Terrace Subdivision will be brought to the Kennedy Sand and
Gravel property south of the subdivision and then treated to
below health-threatening levels before being permanently
deposited there. When this is accomplished in concert with
completion of the groundwater treatment alternative, the remedial
action will be complete.
Sincerely,
Allen P. Beinke
Executive Director
AGb
P 0 Box 13087 Capitol Station • 1700 North Congress Ave. • Austin, Texas 78711 3087 • Area Code 512 463 7S30
-------
APPENDIX E
INDEX TO THE ADMINISTRATIVE RECORD
4
------- |