United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROCVR06-90/057
September 1990
Superfund
Record of Decision:
ro
Texarkana Wood Preserving, TX
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50272-101
I REPORT DOCUMENTATION
PAGE
1. H9ORTNO.
EPA/ROD/R06-90/057
SUPERFUND RECORD OF DECISION
Texarkana Wood Preserving, TX
First Remedial Action
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09/25/90
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U.S. Environmental Protection Agency
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Washington, D.C. 20460
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IS. Supplementary Notee
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EPA/ROD/R06-90/057
Texarkana Wood Preserving, TX
First Remedial Action
^Abstract (Continued)
The selected remedial action for this site includes excavating approximately 77,000
cubic yards of contaminated soil (includes any affected sediment and sludges),
followed by onsite treatment using incineration, leachability testing of residual ash,
and onsite backfilling of ash with the installation of a soil cover and revegetation;
pumping and treatment of approximately 16 million gallons of contaminated ground water
from the shallow aquifer using carbon adsorption, with onsite or offsite regeneration
or offsite disposal of the spent carbon, pretreatment using ferric hydroxide
precipitation and flocculation, followed by clarification and filtration as needed,
and reinjecting the treated water onsite into the shallow aquifer; and implementing
institutional controls, including deed restrictions to limit land use. The estimated
present worth cost for this remedial action is $47,500,000, which includes a total o&M
cost of $1,060,000.
PERFORMANCE STANDARDS OR GOALS: Soil remediation will reduce the excess cancer risk
to below 10~6. Ground water will be restored to its beneficial use as drinking water.
Chemical-specific goals for soil include carcinogenic PAHs 3 mg/kg, total PAHs
2450 mg/kg, dioxin 20 ug/kg, and pentachlorophenol 150 mg/kg. Chemical-specific goals
for ground water include carcinogenic PAHs 10 ug/1 (detection limit), dioxin
0.001 mg/1 (Proposed MCL). CWA requirements for PAHs and dioxin in ground water are
lower than the above values, but ground water will be remediated to below detection
limits as indicated.
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DECLARATION
TEXARKANA WOOD PRESERVING COMPANY
RECORD OF DECISION
SEPTEMBER 1990
Statutory Preference for Treatment as a
Principal Element is Met
and Five-Year Review is Required
SITE NAME AND LOCATION
Texarkana Wood Preserving Company
Texarkana, Bowie County, Texas
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for
the Texarkana Wood Preserving Company site in Texarkana, Texas,
which was chosen in accordance with the Comprehensive Environmen-
tal Response, Compensation and Liability Act of 1980 (CERCLA), as
amended by the Superfund Amendments and Reauthorization Act of
1986 (SARA) and, to the extent practicable, the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP). This
decision is based on the administrative record file for this
site.
The State of Texas supports the selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selec-
ted in this Record of Decision, may present an imminent and
substantial endangerment to public health, welfare, or the en-
vironment.
DESCRIPTION OF THE SELECTED REMEDY
This operable unit is the first of two operable units planned f
the site. This operable unit address the principal threat at t- .
site contributed from the soil and shallow ground water. The
second operable unit will involve continued study and possible
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remediation of the deeper ground water. The function of this
operable unit is to thermally treat all waste above the action
levels.
The major components of the selected remedy include:
Excavation of soils above the remediation goal;
Thermally treating the soils;
Backfill the treated soil.
Extraction of shallow ground water;
Treatment of ground water by carbon adsorption followed by
regeneration of the carbon;
Reinject the treated ground water.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the en-
vironment, complies with Federal and State requirements that are
legally applicable or relevant and appropriate to the remedial
action, and is cost-effective. This remedy utilizes permanent
solutions and alternative treatment technology, to the maximum
extent practicable, and satisfies the statutory preference for
remedies that employ treatment that reduces toxicity, mobility,
or volume as a principal element.
Because this remedy will not leave hazardous substances remaining
on-site above health-based levels, the five year review will not
apply to this action. The ground water remediation is expected
to exceed 5 years. Therefore, a 5 year review will be necessary
during the remediation of the ground water.
Signature (Regiona Administrator) xDate
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TABLE OP CONTENTS
LOCATION AND DESCRIPTION 1
SITE HISTORY AND ENFORCEMENT ACTIVITIES 4
HIGHLIGHTS OF COMMUNITY PARTICIPATION 7
SCOPE AND ROLE OF OPERABLE UNIT WITHIN SITE STRATEGY .... 8
SUMMARY OF SITE CHARACTERISTICS 10
SUMMARY OF SITE RISKS 15
Remediation Goals 19
DESCRIPTION OF ALTERNATIVES 24
Soil Alternatives 24
Common Elements 24
NO ACTION 26
CAPPING 26
THERMAL DESTRUCTION AND BACKFILLING 27
CHEMICAL TREATMENT AND BACKFILLING 29
SOLIDIFICATION AND BACKFILL 31
BIOLOGICAL TREATMENT AND BACKFILLING 32
OFFSITE THERMAL TREATMENT AND DISPOSAL 33
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 34
Threshold Criteria 34
Primary Balancing Criteria 34
Modifying Criteria 35
Analysis 35
Overall Protection 35
Compliance with Applicable or Relevant and Ap-
propriate Requirements (ARARs) 35
Long-term Effectiveness and Permanence 38
Reduction of Toxicity, Mobility, or Volume of the
Contaminants Through Treatment 38
Short-term Effectiveness 38
Implementability 39
Cost 39
State Acceptance 39
Community Acceptance 39
DESCRIPTION OF ALTERNATIVES 40
Ground Water Remedial Alternatives 40
Common Elements 40
EXTRACTION, TREATMENT AND DISCHARGE 41
EXTRACTION, TREATMENT, AND REINJECTION 42
SLURRY WALL 42
NO ACTION 42
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 43
Analysis 43
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Overall Protection 43
Compliance with Applicable or Relevant and Ap-
propriate Requirements ARARs 43
Short-term Effectiveness 43
Long-term Effectiveness and Permanence 46
Reduction of Toxicity, Mobility, or Volume of the
Contaminants through Treatment 46
Implementability f 46
Cost 46
State Acceptance 46
Community Acceptance 46
SELECTED REMEDY 46
Statutory Determinations 50
Protection of Human Health and the Environment 51
Compliance with Applicable or Relevant and Appropriate
Requirements 52
Soil Remediation 52
Action-specific Soil Remediation ARARs .... 52
Chemical-specific Soil Remediation ARARs ... 52
Location-specific Soil Remediation ARARs ... 53
Ground Water Remediation 53
Action-specific Ground Water Remediation
ARARs 53
Chemical-specific Ground Water Remediation
ARARs 53
Location Specific Ground Water Remediation
ARARs 53
Cost Effectiveness 53
Utilization of Permanent Solutions and Alternative
Treatment Technologies (or Resource Recovery
Technologies) to the Maximum Extent Practical: . . 54
Preference for Treatment as a Principal Element .... 55
APPENDIX A 56
APPENDIX B 57
APPENDIX C 58
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I. LOCATION AND DESCRIPTION
The Texarkana Wood Preserving Company (TWPC) site is located
in Bowie County, Texas (Figure 1) . Both the city of
Texarkana and the Bowie County line run through the site off
Lubbock Street and approximately 2800 feet due west of the
Miller County, Arkansas line as shown in Figure 2. Days
Creek, an interstate tributary of the Sulphur River, is
located less than 500 feet east of the site. The site is
within the 100 year flood plain of Days Creek. Fishing may
occur from this creek. The site is bounded to the west by
the Texas and Pacific Railroad right-of-way, to the south by
Lubbock Street and to the north by Lubbock Street. Adjacent
land uses include industrial, residential, and grazing.
A small residential area of approximately 70 families is
located one third of a mile northwest of the site. There
are no schools in this subdivision. Although the aquifer is
considered a Class 2B aquifer, no one is currently using the
aquifer in the vicinity of the site. The majority of the
community around the site is on the city water system and
does not use the ground water for drinking.
The site topography could be described as level ground,
sloping slightly to the southeast. Surface water runs from
the northwestern portion of the site to the drainage ditch-
es along Lubbock street. Shortly after Lubbock street turns
and runs east/west, the runoff heads south into a natural
drainage ditch running through a field, eventually draining
into Days Creek. Surface water on the eastern portion of
the site, travels to the southeast, directly into Days
Creek.
The site stratigraphy consists of Quaternary Alluvium under-
lain by the Wilcox Formation. The Alluvium, called Surfi-
cial Silty Sand and Gravel Zone, consists of silty sand with
gravel and minor sediments with depth. Surface sediments
are predominantly silty sand with occasional silty clay and
silt. The basal deposits are gravelly sand or silty, sandy
gravel. The average thickness of the alluvium is I3h feet
and ranges from 9\ feet to 20 feet. The basal gravel has an
average thickness of four feet and ranges in thickness from
two feet to seven feet. The Quaternary Alluvium is uncon-
formable underlain by the Wilcox Formation.
The Wilcox formation is representative of a fluvial deltaic
depositional environment and consists of clayey and silty
sands with clay, carbonaceous sediments and lignite. The
Wilcox Formation is encountered at an average depth of 13^
feet. The upper portion of the Wilcox consists primarily of
clayey sand and comprises alternating laminae of sand and
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BOWIE COUNTY
I
. TEXARKANA
COLLEGE STATION
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KILOMETERS
CORPUS CHRISTI
FIGURE
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TWPC REMEDIAL
INVESTIGATION
GENERAL LOCATION
TEXARKANA. TEXAS
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clay, with greater than fifty percent of the sediment being
sand. The thickness of the Clayey Sand Zone varies from ap-
proximately 30 feet to 50 feet, with an average thickness of
40 feet.
Sediments consisting primarily of silty sand and poorly-
graded sand with occasional thin layers of carbonaceous
material are encountered below the Clayey Sand Zone. The
Silty Sand Zone is first found at a depth of 44 to 69 feet
and extends to a depth of 90 to 99 feet.
The Lignite unit, consisting of several lignite layers
interbedded with clayey sand or silty clay, is encountered
at a depth of about 99 feet. This unit extends to about a
depth of 115 feet. A deep clay is encountered below this
lignite. The elevation of the top of the Deep Clay Zone
reflects the trend of the regional dip in the Wilcox towards
the south east at an angle of approximately fifteen feet per
mile.
Three different ground water systems control the
hydrogeologic regime at the site: 1) the Surficial Silty
Sand and Gravel Zone; 2) the Clayey Sand and Silty Sand
Zone, and; 3) the Lignite and Deep Clay Zone. A basic
schematic of these is shown on Figure 3. This Record of
Decision addresses the Surficial Silty Sand and Gravel Zone.
In 1972, the site processing area was moved from the south
western portion of the site to the central portion of the
site. Therefore, the site may be broken down into two
parts, the pre-1972 treatment area and the post-1972 treat-
ment area. Both areas have a heavily contaminated process
area, consisting of a number of waste ponds on the west part
of the site, and water retention ponds on the east portion
of the site. Most tanks have been scavenged from the site,
however, a few still remain in the main process area of the
post-1972 treatment area. There are also a few buildings,
and concrete slabs on the site.
II. SITE HISTORY AND ENFORCEMENT ACTIVITIES
The TWPC site has been used for various lumber-related
activities since the early 1900's. Analysis of aerial
photos indicates that wood preserving operations were under-
way as early as 1954 in the southwestern portion of the
site. The wood-treating activities leading to the current
site configuration were begun in late 1971 by the TWPC and
included the use of both creosote and pentachlorophenol
(PCP). Figure 4 shows the location of the wood preserving
operations identified throughout the site history.
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Between 1903 and 1910, the site was owned and operated by
several lumber companies including; the National Lumber
Company, the Southern Tie and Timber Treating Company, and
the National Lumber and Creosoting Company. These three
companies operated on a 15-acre tract east of the railroad,
west of the north-south portion of Lubbock Street, north of
the southern property boundary now marked by the EPA fence,
and south of Lubbock Street where it crosses the railroad
tracks. The extent of wood-treating activities during this
period is unknown.
Several individuals owned portions of the site between 1910
and 1920, but deed records do not identify site uses during
this decade. In mid-1920, the Consolidated Lumber Company
acquired 25.37 acres (which roughly corresponds to the
boundaries now delineated by the EPA fence) and operated at
the site for about two years. The State Line Lumber Company
took over the site in 1933. Nothing is known about poten-
tial contaminating activities at the site during these
periods.
Clara B. Butcher, or her heirs, owned the site from 1933
until it was sold to TWPC in 1981. During that time,
various companies leased the property. The Power Mill and
Lumber Company (later the Thomas E. Power Lumber Co.) held a
lease fron 1942 for an indeterminate length of time. In
1946, the site was leased to the Charles H. Proetz Lumber
Company for a minimum period of five years. Analysis of an
aerial photo taken in 1954 indicates what appears to be
creosoting operations in the southwestern corner of the
site. This is the first evidence of on-site creosoting
activities.
The portion of the site east of Lubbock Street appeared to
be occupied by office buildings or workshops. North of the
apparent processing area, on the west side of Lubbock
Street, the site was used for lumber storage. There was a
large building located just north of where the pretreatment
storage ponds are today.
The TWPC first came to the attention of the State of Texas
following discharges into Days Creek. The first State
investigation occurred in December of 1968. The following
sixteen years, until the TWPC ceased operation in August
1984, were marked by a series of State investigations in
which the TWPC was found to be either negligent or delin-
quent in their efforts to fulfill various permitting re-
quirements.
The site was nominated to the National Priorities List (Ni
in December 1984. In June 1986, the site was included on
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the third NPL update. Subsequently/ EPA has taken measures
to control surface runoff and site access. Stabilizing
actions taken by EPA from 1986 to 1988 included constructing
fences to minimize access, constructing a berm around the
main operations pond to prevent surface runoff and pumping
down this and other ponds to prevent overflow. The pumped
liquid, primarily rain water runoff, was put in pond number
1.
Fourteen potentially responsible parties (PRP; former owner
and/or operators) were identified in a PRP search conducted
in 1985. On January 16, 1986, 104(e) Notice Letters were
sent to the PRPs notifying them of their potential liability
and of planned investigations at the site. The PRPs con-
tacted were asked if they would like to either conduct or
finance the Remedial Investigation and Feasibility Study
(RI/FS) at the site. Of the PRPs notified, all declined to
participate in the RI/FS process. On December 17, 1986, an
action letter was sent to the PRPs informing them of an
imminent and substantial endangerment to public health or
welfare or the environment due to actual or threatened
releases of hazardous substances from the site and asked to
post warning signs and install a fence around the site. All
the notified PRPs declined to voluntarily install warning
signs and a fence. On February 5, 1987, Special Notice
Letters were sent to PRPs asking them to participate in the
RI/FS. All the PRPs declined to participate in the RI/FS.
A revised 104(e) Information Request letter was issued to 13
identified PRPs on August 23, 1990. These 13 PRPs were
involved at the site from 1960-1984. The notified PRPs will
have 30 days from receiving their letter to respond. The
focus of this 104(e) letter is to determine the financial
viability of PRPs. A Special Notice letter has been drafted
and will be sent to all identified PRPs asking them to
participate in and/or finance the Remedial Design at the
site. The other PRP who was not sent the 104(e) letter will
be sent a similar letter, except the questions will be
modified to address the period of time at which the PRP
operated at the site (1930s-1940s). Should the PRPs decline
to conduct future remedial action activities, EPA will
either take enforcement actions and/or provide funding for
these activities while seeking cost recovery for all EPA-
funded response actions from the PRPs.
III. HIGHLIGHTS OF COMMUNITY PARTICIPATION
A Community Relations Plan for the Texarkana Wood Preservir :
site was finalized in December 1987. This document lists
contacts and interested parties throughout government and
the local community. It also establishes communication
pathways to ensure timely dissemination of pertinent infer-
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nation. The Remedial Investigation was released to the
public in June of 1989. The Feasibility Study and the
Proposed Plan were released to the public in July 1990. All
of these documents were made available in both the Administ-
rative Record and two information repositories maintained at
the Texarkana Public Library and Texarkana City Hall. A
public comment period was held from July 12, 1990 to August
11, 1990. In addition, a public meeting was held on June 28
1989 to present the results of the remedial investigation
and on July 24, 1990 to present the results of the
feasibility study and the preferred alternative as presented
in the Proposed Plan for the site. 42 comments were
received during the public comment period. These comments,
including those expressed verbally at the public meeting are
addressed in the Responsiveness Summary which is attached as
Appendix A to the Record of Decision.
IV. SCOPE AND ROLE OF OPERABLE UNIT WITHIN SITE STRATEGY
As with many Superfund sites, the problems at the Texarkana
Wood Preserving Company are complex. During the inves-
tigation it was determined that the deeper ground water is
contaminated. To expedite the remediation of the source and
the shallow ground water, this site was broken into two
parts, called operable units. These are:
Operable Unit One: Contaminated Soils and Shallow Ground
Water (average depth of 13.5 feet)
Operable Unit Two: Lower Ground Water
This Record of Decision addresses operable unit one. The
studies undertaken at the Texarkana Wood Preserving Company
site have identified two principal threats to be addressed
in the first operable unit: contaminated soil and shallow
ground water. The contaminated soil was determined to be a
principal threat to human health and the environment at the
site. The potential routes of exposure are through direct
contact with and ingestion of the soil and ground water, as
well as the soil's leaching potential to the ground water.
The operations and chemical holding ponds contribute greatly
as the principal risk. The soil outside these ponds
represents lower level risk. These ponds are identified in
Figure 4. The shallow ground water is not currently being
used near the site. However, it has a potential to be used,
therefore, it is considered a class 2-B aquifer. The con-
tamination in both the soil and the shallow ground water is
above health-based levels (as detailed in the Summary of
Site Risk section). The remedial objectives for the soil
are to prevent current or future exposure to the contaminat-
ed soil through treatment and/or containment, and to reduce
the migration of contaminants from the soil to ground water.
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The contaminated shallow ground water was also determined to
be a principle threat at the site because of the potential
of ingestion and potential of migration of contaminants to
deeper zones of ground water. The deeper ground water zones
are used for industrial, irrigation, and drinking water
purposes. The remedial objectives for the contaminated shal-
low ground water is to address the principle threat by
reducing the amount of contamination, return the groundwater
to its beneficial use and to prevent adverse impact to lower
ground water zones. This can be accomplished by establish-
ing, and remediating the ground water to health based
levels.
The alternatives considered to address the soil and ground
water contamination satisfy the statutory preference for the
reduction of toxicity, mobility, or volume through treatment
as a principal element.
V. SUMMARY OF SITE CHARACTERISTICS
As previously discussed, the site may be broken down into
two parts, the pre-1972 treatment area and the post-1972
treatment area. Both areas have a heavily contaminated
process area, consisting of a number of treatment, chemical
storage and water retention ponds (Figure 4). As one may
expect, the soil surrounding these areas and the shallow
ground water is contaminated with the wood preserving wastes
pentachlorophenol and creosote. Also found on the site were
mercury and dioxin. The major contaminants of concern may
be grouped, in a broad sense, as semivolatiles including
such compounds as pentachlorophenol, naphthalene, pyrene,
chrysene, benzo(a)anthracene and benzo(a)pyrene.
Pentachlorophenol is one of the most heavily used pesticides
in the United States. Pentachlorophenol does not occur
naturally in the environment. Pentachlorophenol is rapidly
degraded under certain conditions in air, on land, and in
water. Results from animal studies indicate that short-
term, high-level exposure to pentachlorophenol can damage
the liver, kidneys, skin, lungs, nervous system, and
gastrointestinal tract. The major organs or systems af-
fected by longer-term exposure to lower levels of pen-
tachlorophenol in animals are the liver, the kidneys, the
nervous system, and the immune system. An increased risk
for cancer has been demonstrated in animals exposed to
pentachlorophenol. Pentachlorophenol is mobile in soil and
tends to migrate from the soil into the ground water. The
highest concentration of pentachlorophenol is 1,400 ppm, 4.1
ppm and 5,100 ppm in the soil, shallow ground water, and
pond sludge respectively.
10
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Creosote is a common wood preserving product. Creosote is
primarily made up of polynuclear aromatic hydrocarbons like,
anthracene, fluoranthene, pyrene, benzo(a)anthracene,
chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, ben-
zo(a)pyrene, indeno(1,2,3-cd)pyrene, dibenzo(a,h)anthracene,
and benzo(g,h,i)perylene. Polynuclear aromatic hydrocarbons
are a group of chemicals that are formed during the incom-
plete burning of coal, oil and gas, garbage, or other or-
ganic substances. Polynuclear aromatic hydrocarbons can be
both man-made or naturally occurring. They are found
throughout the environment in the air, water, and soil.
Several of the polynuclear aromatic hydrocarbons have caused
cancer in laboratory animals. Certain polynuclear aromatic
hydrocarbons are, therefore, considered as probable car-
cinogens (like benzo(a)pyrene). Studies in animals have
also shown that polynuclear aromatic hydrocarbons can cause
harmful, non-carcinogenic effects on skin, body fluids, and
the body's system for fighting disease after both short-and
long-term exposure. These effects have generally not been
seen in humans. The highest concentration of carcinogenic
polynuclear aromatic hydrocarbons is 1,396 ppm, .137 ppm and
3,918 ppm as benzo(a)pyrene in the soil, shallow ground
water, and pond sludge respectively.
Chlorinated dibenzo-p-dioxin and dibenzofuran (commonly
called dioxin and furan) are also contaminants of concern at
the site. Dioxin and furans are impurities in pentachloro-
phenol. Dioxin is a group of compounds. The most toxic of
the group is known as 2,3,7,8-TCDD. At the present time
2,3,7,8-TCDD is not used for any purpose other than scien-
tific research. Dioxin is a man-made compound. Dioxin is
very immobile in soil. In humans, TCDD causes severe skin
irritations that usually occurs on the head and upper body.
There is suggestive evidence that TCDD causes liver damage
and digestive disorders in humans. Animal studies have
indicated that dioxin is toxic to the immune system, and
promotes adverse reproductive effects, although this latter
effect has not been demonstrated in humans. The human
evidence for TCDD alone is inadequate to demonstrate or
reflect a carcinogenic hazard. Based on the positive
evidence provided through animal studies, TCDD is considered
by EPA to be a probable human carcinogen. The maximum
concentration in the soil, ground water and pond sludge are
76 ppb, 10.6 ppb and 302 ppb 2,3,7,8 TCDD equivalents
respectively.
The past wood preserving activities at the site have result-
ed in an estimated 77,000 cubic yards of soil, sludge, and
sediment, and 16 million gallons of shallow ground water
contaminated with pentachlorophenol, polynuclear aromatic
hydrocarbons, and dioxin. This soil estimate includes con-
taminated material in the saturated zone.
11
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Three primary areas of widespread soil contamination were
identified at the site. These areas are shown on Figure 5.
The first area surrounds the "post-1972 process area" and
covers an area of roughly 180,000 square feet. The con-
tamination in this area extends north of the process area
nearly to the north site fence and across the entire width
of the west side of the site. Contaminated soils in this
area constitute an estimated volume of 26,100 cubic yards.
The second area of contamination is the process area in the
southwest corner of the west side, the "pre-1972 process
area" which also covers about 180,000 square feet. The
contamination in this area begins in the south central part
of the west side and extends about 50 feet south of the
south fence. The far southwest corner of this area con-
tains the most severe contamination. Semi-volatile con-
centration range from below the detection limit to 18,000
mg/kg in this area. Approximately 17,800 cubic yards were
calculated to be contaminated.
A third area of contamination on the east side is less well
defined than the other two areas. The semivolatile con-
tamination has no obvious source and covers approximately
100,000 square feet. Soil is contaminated at concentrations
below the detection limit to 870 mg/kg, and constitute a
volume of approximately 18,400 cubic yards.
Two distinct plumes of contaminated ground water originating
from the former two process areas were identified in the
shallow ground water contained in the Gravel Zone at the
site. These plumes are referred to as Area A and Area B on
Figure 6.
The Area A plume is the larger and contains an estimated 14
million gallons of ground water contaminated with semi-
volatiles. The Area A plume's major source is the main
process area. Detectable concentrations in the plume range
from 84 mg/L total semi-volatiles (principally,
pentachlorophenol and non-carcinogenic polynuclear aromatic
hydrocarbons) just down gradient of the source to 0.024 mg/1
total semi-volatiles at the extreme south edge. Free
creosote, in a separate phase, was detected just down
gradient of the source.
A smaller contaminated ground water plume extends about 400
feet southeast from the old process area in the southwest
corner. The sources of this contamination are probably
ponds 11, 12 and 13 and the wide spread soil contamination
extending to the shallow ground water. An estimated 2.1
million gallons of contaminated ground water is contained in
the Area B plume. Concentrations of semi-volatile
12
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(principally pentachlorophenol) organics range from 22 mg/1
closest to the source to 0.69 mg/1 at the plume's edge.
Preliminary sampling of the lower water-bearing zone, the
Silty Sand Zone, indicates it is contaminated. Total semi-
volatile concentrations of 0.86 and 0.065 mg/1 were found in
this zone. No volume in the Silty Sand Zone could be calcu-
lated with only two wells. Contamination in this zone
probably originated in the contaminated shallow ground water
above this zone.
The population of Texarkana is approximately 33,500. No one
lives on the site. The immediate area, within one half
mile, includes industries and a small residential community
of about 70 homes. This residential community is about 1/3
mile from the site. Approximately 1,000 people live within
a 1 mile radius. The site is fenced and hazard signs are
posted around the site to discourage people from entering
the site. Contamination continues to migrate from the soil
through leachate generation and surface runoff. Surface
runoff may carry contaminants into Days Creek.
Approximately 95% of the surface contamination is within the
fenced boundary of the old facility. Only about 5% of the
contamination is outside the boundary of the fence in the
southwest corner of the west portion of the site. This
decision document addresses the shallow ground water, as
well as the soil, sludge, and sediment, on and off site,
which is the most heavily contaminated ground water zone.
The saturated zone of the shallow ground water is classified
as a 2B aquifer with an average depth of 13.5 feet, and
appears to have two distinct plumes. The deeper zones are
still under investigation. Contamination in these zones are
only slightly above the detection limit for non-carcinogenic
polynuclear aromatic hydrocarbons.
VI. SUMMARY OP SITE RISKS
A risk assessment is a scientific procedure which uses facts
and assumptions to estimate the potential for adverse effect
on human health and the environment from exposure to chemi-
cals. Risk is determined by evaluating known chemical
exposure limits and actual chemical concentrations on site.
The actual chemical concentrations are compared to the level
of exposure to the chemical shown to cause harm. The risk
potential is expressed in terms of the chance of a disease
occurring. Conservative assumptions that weigh in favor of
protecting human health and the environment are made in this
calculation. To protect human health, the EPA is most
concerned with the probability that exposure to specific
chemicals may result in cancer.
15
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The national risk of developing some form of cancer from
everyday sources over a 70-year life span is estimated at
three in ten. Activities such as too much exposure to the
sun, occupational exposures, or smoking habits contribute to
this high risk. The three in ten probability is the "natur-
al incidence" of cancer. To protect human health, the EPA
has set the risk range of one in ten thousand to one in one
million excess cancer risk as a goal for Superfund sites.
These may also be described by scientific notation: 1x10"*
to 1x10 . A risk level of 1 in 1,000,000 means that one
additional person out of 1 million people exposed could
possibly develop cancer as a result of extensive continuous
exposure to the site.
The risk assessment begins by evaluating the current site
risk, also called site baseline risk, posed to human health
by the Texarkana Wood Preserving Company site. Since the
site is currently unoccupied, information from the local
officials was obtained to determine a likely future land
use. This information indicated that the most likely future
land use scenario for the site is industrial. The site is
within the 100-year flood plain, and many industrial areas
surround the site. Therefore, the future use of the site
focused on the effects of a worker exposure to the con-
taminants. The risk assessment determined that the chemi-
cals which pose the greatest health threat to workers are
polynuclear aromatic hydrocarbons (i.e., creosote), pen-
tachlorophenol, and polychlorinated dibenzo-p-dioxin and
dibenzofuran.
Under the future use evaluation, assuming site conditions
are unchanged, the baseline risk assessment indicated that
the increased chance of cancer a worker would have would be
one in one hundred (1:100). Most of the risk was posed by
the dermal absorption from soil and incidental ingestion of
soil exposure pathway. Almost 100 percent of the car-
cinogenic risk was posed by the carcinogenic polynuclear
aromatic hydrocarbons. The baseline risk also indicated
there is an increased chance for non-carcinogenic health
effects, (health effects other than cancer) from total
polynuclear aromatic hydrocarbons and chlorinated dibenzo
dioxin and furans. This assumed a 40-year tenure at the
site, working 50 weeks per year, 5 days per week, 8 hours
per day, exposure to the maximum concentration of the chemi-
cals, a worker weight of 154 pounds (70 Kg), and worker
consumption of .1 gram of soil per day, (half is ingested i*
work). The slope factor (previously known as the cancer
potency factor) for benzo(a)pyrene of 11.5 (mg/kg/day) "^ ar :
a reference dose of 1.2xlO"3 (mg/kg/day) for polynuclear
aromatic hydrocarbon were also used. As a result of the
conservative assumptions, the risk assessment should not :
16
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construed as presenting an absolute estimate of risk to
human health. Rather it is a conservative analysis intended
to estimate the potential for adverse health effects to
occur.
The site is separated into east and west sections by Lubbock
Street which runs in a roughly north-south direction. The
west section is secured by a low barbed wire fence on the
south and west borders and by a six feet high chain link
fence on the north and east borders. The barbed wire fence,
as well as traffic on each side on the site, would most
likely deter children from trespassing on the property.
However, these boundaries would not prevent adult
trespassers from entering the site to salvage equipment.
The trespasser is assumed to spend eight hours per day on
the site, two days per week for two weeks during one year.
This is the "current use" scenario.
Soil concentrations of indicator chemicals (which include
pentachlorophenol, naphthalene, benzo(a)pyrene and dioxin)
were averaged over the entire site for this scenario since
it is assumed the individual would walk throughout the site.
The soil concentrations are only used for the inhalation
pathway in this scenario; exposure to contaminants through
dermal contact and incidental soil ingestion were based on
sludge concentrations. Incidental ingestion and dermal
contact exposures were bases on sludge contact because it is
assumed that the adult trespasser would be on the site for
the purposes of salvaging equipment which is located in
areas with a significant presence of sludge.
The potential upperbound carcinogenic risk estimated for the
trespasser ranged from approximately one in one million
based on the average contaminant concentration to 4 in one
hundred thousand based on the maximum contaminant concentra-
tion. The major portion of the risk was posed by dermal
absorption from sludge and incidental sludge ingestion. Of
the contaminants, the carcinogenic polynuclear aromatic
hydrocarbons contributed close to 100 percent of the risk.
The risk assessment also indicated non-carcinogenic health
effects will occur under this scenario. People living in
the vicinity of the site are not currently at risk from the
site.
Table 1 outlines baseline risks calculated for the worker
and trespasser scenario. For more information on the risk
assessment, refer to Appendix B in Volume 2 of the
Feasibility Study Report, July 1990.
17
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Remediation Goals
The next step in the risk assessment is to determine what
levels of the chemicals at the site would not pose adverse
health effects. Following methodology refined by the and
published in the Superfund Public Health Evaluation Manual.
1986 OSWER Directive 9285.4-1 and Risk Assessment Guidance
for Human Health Evaluation Manual. 1989 OSWER Directive
9285.701, EPA determined remediation goals.
In December 1989, EPA's Office of Emergency and Remedial
Response published the interim final Risk Assessment
Guidance for Superfund (RAGS)-Volume I. The purpose of this
guidance was to supersede the Superfund Public Health Evalu-
ation Manual (SPHEM) and Endangerment Assessment Handbook
which, to that date, had been used for assessing the effects
of chemical contamination on human health. RAGS revised the
SPHEM methodology in several ways.
One key modification came through the introduction of the
concept of Reasonable Maximum Exposure (RME). RME is
defined as the highest exposure that could reasonably be
expected to occur at a site. This approach differs from the
SPHEM approach of defining worst-case exposure to site
contaminants. One of the primary differences is that while
SPHEM utilized a "worst-case" scenario based on continued
exposure to the maximum detected concentration of a chemical
constituent at the site, RME bases the maximum exposure on
the 95% upper confidence limit of the mean, providing a
spatially averaged exposure concentration.
While there are advantages and disadvantages realized in
both the SPHEM and RAGS methods, the Texarkana Wood Preserv-
ing Record of Decision summarizes the results of the risk
assessment conducted under SPHEM guidance. RAGS was not
used because at the time of its publication, the risk as-
sessment for the Texarkana Wood Preserving site was nearing
completion. Considering that the underlying assumptions
utilized under SPHEM were at least as conservative as those
used in RAGS, the results of the risk assessment would be at
least as protective as those which would have been derived
under exposure parameters (such as body weight, ingestion
rates, exposure frequencies and durations, etc.) which were
consistent with the RAGS. Therefore, the decision was made
to complete the risk assessment under the SPHEM guidance.
The following summary highlights the methodology used in the
risk assessment process. Only the worst case risk (based on
the maximum contaminant concentration) is presented. The
same conservative assumptions were used in deriving the
remediation goals as used in the baseline risk assessment.
19
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As previously mentioned, the future use of this site will
most likely be an industrial, therefore an industrial ex-
posure scenario was developed. This exposure scenario is
based on an individual working on the site for 40 years, the
other assumptions are the same as above.
Cancer Causing Compounds;
The creosote compounds (polynuclear aromatic hydrocarbons,
see Table 2) known or suspected to be cancer causing vary in
toxic potency. Many of these compounds also cause non-car-
cinogenic effects, creating a complex toxicity picture. The
exposure and uptake of these compounds vary with the cir-
cumstances on the site and with the mixture of polynuclear
aromatic hydrocarbon present. In order to relate each
complex mixture of polynuclear aromatic hydrocarbons to the
other, the EPA has drafted an equivalency rating for each
compound. This equivalency system relates the toxicity of
benzo(a)pyrene, considered the most toxic polynuclear
aromatic hydrocarbon, to the other polynuclear aromatic
hydrocarbon. The equivalency factors are shown on Table 2.
Some dioxin and furans are also known to be cancer causing
and are present in the soils at the site. The potential
threat to human health posed by chlorinated dioxin and
furans is based on the established criteria for 2,3,7,8-
tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). Chlorinated
dibenzofurans and other isomers of dioxin are considered to
be less toxic than 2,3,7,8-TCDD and are expressed in toxic
equivalents of 2,3,7,8-TCDD. Therefore, although 2,3,7,8-
TCDD is not a major contributor to the dioxin concentration
at the site, the target action level for dioxin and furans
is expressed in toxic equivalencies of 2,3,7,8-TCDD.
Guidance used to evaluate the levels present in soil at
Texarkana Wood Preserving site include Interim Procedures
for Estimating Risks Associated with Exposures to Mixtures
of Chlorinated Dibenzo-p-Dioxin and -Dibenzofurans (CDDs and
CDFs) and 1989 Update. EPA/625/3-89/016, March 1989. These
equivalency factors are shown on Table 3.
Non-Cancer Causing Compounds;
Although some compounds at the site do not cause cancer,
they do cause other health effects. The chemicals of con-
cern in this group are pentachlorophenol and the non-cancer
causing polynuclear aromatic hydrocarbons (e.g., naph-
thalene, acenaphthene, acenaphthylene and fluorene).
As with the cancer causing polynuclear aromatic hydrocar-
bons and dioxin, the non-cancer causing polynuclear aromat-
ic hydrocarbons have a specific compound the toxicity of the
non-cancer causing compound are related to. All non-cancer
causing polynuclear aromatic hydrocarbons are considered
20
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TABLE 2
TEXARKANA WOOD PRESERVING COMPANY
RELATIVE POTENCY FACTORS
FOR CARCINOGENIC POLYNUCLEAR AROMATIC HYDROCARBON
(as Benzo(A)Pyrene)
COMPOUNDS RELATIVE POTENCY
Benzo(a)Pyrene 1.0
Dibenzo(a,h)anthracene 0.069
Benzo(b)fluoranthene 0.08
Indeno(l,2,3-c,d)pyrene 0.0171
Benzo(a)anthracene 0.0134
Benzo(g,h,i)perylene 0.01
Benzo(k)fluoranthene 0.044
Chrysene 0.0012
-------
TABLE 3
1989 EPA 2,3,7,8-TCDD TOXICITY EQUIVALENCY FACTORS
ISOMER
2,3,7,8 TCDD
Other TCDD
2,3,7,8-PeCDD
Other PeCDD
2,3,7,8-HxCDD
Other HxCdd
2,3,7,8-HpCDD
Other HpCDD
OCDD
2,3,7,8-TCDF
Other TCDF
1,2,3,7,8-PeCDF
2,3,4,7,8-PeCDF
Other PeCDF
2,3,7,8-HxCDF
Other HxCDF
2,3,7,8-HpCDF
Other HpCDF
PROPORTIONALITY
FACTOR
.05
0.95
0.07
0.93
0.3
0.5
0.5
0.5
1
0.03
0.97
0.04
0.04
0.92
0.25
0.75
0.5
0.5
1989
TEF
1
0
0.5
0
0.1
0
0.01
0
0.001
0.1
0
0.05
0.05
0
0.1
0
0.01
0
EXAMPLE
CALCULATION
(Total TCDD) x( 0.05) =
(Total PeCDD) x( 0.035)=
(Total HxDCC)x(0.03) =
(Total HpCDD) x( 0.005)=
(OCDD)X(O.OOI)
(Total TCDF)x(0.003) =
(Total PCDF)X(0.002) =
(Total PCDF)X( 0.002) =
(Total HxCDF) x( 0.025)=
(Total HpCDF) x(0. 005)=
OCDF
0.001 (OCDF)X(O.OOl)
Additive Total= 2,3,7,8
TCDD
Equivalent
-------
equal to naphthalene because it is among the most prevalen-
tand most studied non-cancer causing polynuclear aromatic
hydrocarbon. The baseline risk assessment indicated that
the non-cancer causing compounds do not present a risk by
themselves. However, when combined with the non cancer
effects associated with the cancer causing polynuclear
aromatic hydrocarbons there is a potential for adverse
effects to human health and the environment. Therefore, a
"total polynuclear aromatic hydrocarbon" remediation level
was established.
Based on the baseline risk assessment, i.e., in the case of
the industrial scenario, the ingestion of the concentrations
of pentachlorophenol in the soil, on site, will not cause
adverse health effects. However, the concentration in the
soil is having a severe adverse effect on the shallow ground
water, which may cause future adverse effect on human health
through the deeper aquifer. Therefore, a remediation level
was established for the soil to protect the ground water and
the environment.
The levels the EPA has determined will provide protection of
human health and the environment, based on an industrial
exposure scenario, are the following:
SOIL:
Carcinogenic polynuclear aromatic hydrocarbons 3 parts per
million as benzo(a)pyrene equivalents.
Total polynuclear aromatic hydrocarbons 2450 parts per
million.
Chlorinated dibenzo-p-dioxin and dibenzofuran 20 parts per
billion as 2,3,7,8 TCDD equivalents.
Pentachlorophenol 150 parts per million
SHALLOW GROUND WATER:
Pentachlorophenol 0.2 parts per million
Carcinogenic polynuclear aromatic hydrocarbons 2.8 parts
per trillion as benzo(a)pyrene equivalents or to below
detection limit.
Chlorinated dibenzo-p-dioxin and dibenzofuran 2.2xlo~4
parts per trillion as 2,3,7,8 TCDD equivalents or to below
detection limit.
The ground water remediation level established for pen-
tachlorophenol is a proposed Maximum Contaminant Level
(MCL). The ground water remediation levels established for
both the carcinogenic polynuclear aromatic hydrocarbons and
the dioxin are the Federal Ambient Water Quality Criteria
standards which are based on a IxlO"6 excess cancer risk.
These standards are below the analytical detection limit for
23
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these compounds and are therefore immeasurable. The
analytical detection limit of 10 ppb for carcinogenic PNAs
and .001 ppb for dioxin/furans will be the goal for the
ground water.
The remediation goals the EPA is proposing will reduce this
risk to at least one in one hundred thousand (1:100,000),
one thousand times safer than what the baseline risk assess-
ment indicated is currently posed by the site and within the
risk range of IxlO"4 to 1x10 as directed by the National
Oil and Hazardous Substances pollution Contingency Plan,
Thursday, March 8, 1990.
An Environmental Assessment was performed to determine
whether the site contamination has impacted on-site and off-
site vegetation and animal life. More specifically, the
purpose of the program was to determine if site contaminants
have entered the food chain and pose a risk to human health.
No endangered species were noted on-site at any time. The
site does appear to have some wetland vegetation. It is
believed that to remediate the site will improve these areas
and promote wetland development. Biological sampling indi-
cated the contaminants are not accumulating in the animal
life on the site or in Days Creek. No signs of stunted
growth in vegetation that could be correlated with a con-
tamination response were apparent. In areas where known
contamination occurred, the vegetation is similar in size to
other comparable areas off-site.
For more information about the Risk Assessment, refer to
Appendix B in Volume 2 of the Feasibility Study.
VIII. DESCRIPTION OF ALTERNATIVES
Soil Alternatives
The alternatives for the soil remediation are the following:
Alternative A-l: No Action
Alternative A-2: Capping
Alternative A-3: Thermal Destruction and Backfilling
Alternative A-4: Chemical Treatment and Backfilling
Alternative A-5: Solidification and Backfilling
Alternative A-6: Biological Treatment and Backfilling
Alternative A-7: Offsite Thermal Destruction
Common Elements: Except for the "No Action" and "Capping"
in place alternatives, all of the alternatives now being
considered for the site would include a number of common
elements. All alternatives involve excavation of ap-
proximately 77,000 cubic yards of on-site soil above EPA's
on site remediation goals. "Contaminated Soil" means all
soil, sludge, and sediment contaminated above the EPA
remediation goals. The proposed excavation would include
24
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soil in the upper ground water region, to help expedite the
remediation of the ground water. Shallow ground water monit-
oring activities will be conducted after soil remediation to
ensure that the remedy is effective. An air monitoring
plan would be implemented to reduce/eliminate any adverse
short term health effects during excavation and treatment
activities. After treatment and replacement, the treated
soils will be covered with clean topsoil and revegetated.
Deed recordation will be obtained in preventing future use
of the site. The State of Texas does not have a mechanism
to force a landowner to record anything on the deed. The
water rights are also the landowner's, so institutional
controls are difficult to enforce.
Alternative A-7 involves treatment and disposal of these
soils offsite; all other alternatives involve onsite treat-
ment or containment of the soil.
ARARs
The origin of the wastes identified on site were compared to
RCRA listed hazardous wastes. The wastes were not iden-
tified as being RCRA listed hazardous wastes. Additionally,
based on current information, the wastes are not considered
"characteristic" of hazardous wastes. Although a new
definition of "toxicity characteristic, (TC)" was es-
tablished for the leachability of pentachlorophenol of 100
parts per million, it is not expected that Texarkana Wood
Preserving waste sample extract or leachate resulting from
application of the TCLP will exceed this limit. As a
general rule of thumb, waste concentrations below 20 times
the "TC" leachate concentration will not exceed the "TC"
leachate concentration in the extract.
Because the waste are not RCRA waste, RCRA Land Disposal
Restrictions as presented in 40 CFR Part 268 are not ap-
plicable. Furthermore, Superfund Land Disposal Restrictions
Guide Number 7, "Determining When Land Disposal Restrictions
(LDRs) Are Relevant and Appropriate to CERCLA Response
Actions", states that EPA will not consider the Land Dis-
posal Restriction to be relevant and appropriate for soil
and debris contaminated with hazardous substances that are
not RCRA restricted wastes. Therefore, Land Disposal
Restriction are not considered relevant and appropriate for
the dioxin-contaminated soils at the Texarkana Wood Preserv-
ing site.
Continuing this thought, because the waste are not RCRA
hazardous waste, the regulations pertaining to hazardous
waste (for example 40 CFR Part 264) are not applicable, but
may be considered relevant and appropriate. The discussion
25
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of relevance and appropriateness will be covered in each
alternative.
Costs
All costs and time required to implement the alternatives
are estimates. The costs have a degree of accuracy of +50%
to -30%.
Soil Alternative A-l:
NO ACTION
Present Worth: $680,000
Capital Cost: $210,000
Operation and Maintenance: $470,000
Years to Implement: 30
The Superfund program requires that a no action alternative
be considered at every site as a basis of comparison when
evaluating other alternatives. No action would consist of
erecting a new fence around the entire site, and monitoring
the air and ground water for 30 years. "No Action" would
not be protective of human health and the environment.
Therefore, "No Action" is not a favored alternative by the
EPA for this site. This alternative would not decrease the
toxicity, mobility, or volume of contaminants or reduce
public health or environmental risks. The quality of the
ground watsr would probably continue to degrade.
Soil Alternative A-2:
CAPPING
Present Worth: $7,300,000
Capital Costs: $6,900,000
Operation and Maintenance costs: $430,000
Years to Implement: 1
Install multi-layer cap over site.
The capping alternative calls for all soils above the
remediation level to be capped on site. In this alterna-
tive, a RCRA Subtitle C cap would be considered relevant an.
appropriate. The cap would consist of three feet of clay,
80 mil high density polyethylene synthetic liner placed
above the clay, one foot of topsoil above the synthetic
liner and a vegetative cover. As this site is in the 100-
year flood plain of Days Creek, an important design con-
sideration would be to maintain the flood storage of the
creek's watershed. A treatability test was not performed .
the feasibility study on this alternative.
No treatment of the soils would be done before the site wa
sapped. Although the mobility of the contaminants in the
soil would be reduced if a cap were constructed over the
site, the volume of the contaminated soils and the toxici*
26
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of the contaminants would not be reduced. Theoretically,
the excess cancer risk would be eliminated because the cap
would eliminate the possibility of exposure.
A variation of this alternative would be consolidating all
or a portion of the waste before capping. Specifically
evaluated in this alternative was consolidating all 77,000
cubic yards of waste under a cap on the west half of the
site.
EPA is directed by Federal environmental regulations to
"utilize permanent solution and alternative treatment tech-
nologies or resource recovery technologies to the maximum
extent practicable"and to prefer remedial actions in which
treatment "permanently and significantly reduces the volume,
toxicity, or mobility of hazardous substances, pollutants,
and contaminants as a principal element".
Since hazardous waste will be left on the site, "landfill"
closure will apply. RCRA regulations affecting landfill
closure require the site to be capped, with a final cover
designed and constructed to provide long-term protection of
human health and the environment through minimization of the
infiltration of liquids through the capped area and proper
maintenance of the integrity of the cap over time with main-
tenance. This type of closure anticipates that post closure
care and maintenance will be carried out at the facility for
at least 30 years. If the wastes are not consolidated, the
"landfill" closure regulations will be relevant and ap-
propriate. If the wastes are consolidated, the landfill
closure regulations will be applicable. In either case,
long-term monitoring and maintenance of the site, including
ground water monitoring and cap repairs, would be required
to guarantee the effectiveness of this remedy.
Deed recordation would be obtained to prevent future use of
the site. However, the State of Texas does not have a
mechanism to force a landowner to record anything on the
deed, and the water rights are also the landowner's, so
institutional controls are difficult to enforce. Deed
recordation will be requested. It may not be possible to
delete the site from the National Priorities List if this
alternative is selected.
Soil Alternative A-3
THERMAL DESTRUCTION AND BACKFILLING
Present Worth: $43,100,000
Capital Costs: $42,000,000
Operation and Maintenance: $60,000
Years to Implement: 2.5
Excavate contaminated material and thermally destroy.
27
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Backfill and grade with the treated soil.
Thermal destruction is the controlled combustion of organic
wastes. Many types of thermal destruction units are
suitable for this alternative. The cost and implementation
time are based on two rotary kiln incinerators operating at
4 cubic yards per hour (cy/hr). The incinerators will be
run continuously (24 hours/day) to avoid start up delays as-
sociated with intermittent operations. Reduction of
toxicity, mobility and volume of contaminated waste is
achieved by thermal destruction.
Since the recognized method for the treatment of dioxin and
furan under the land disposal restrictions is thermal
destruction there is a high degree of confidence in this
alternative. Treatability studies were not done during the
feasibility study. As discussed in the Common Elements
section, the site contaminants are not RCRA hazardous waste.
Therefore, 40 CFR Part 264 Subpart 0 in not applicable.
However, the wastes are similar, therefore, performance
standards are relevant and appropriate. A test burn will
be necessary to determine operating parameters (feed rate,
temperature, material handling techniques, etc.,) and to
verify compliance with Subpart O of 40 CFR Part 264. Also
to be considered are the proposed incineration regulations,
Federal Register Friday, April 27, 1990, which address
products of incomplete combustion, metals, and hydrochloric
acid. A thermal destruction unit burning hazardous waste
must achieve a destruction and removal efficiency of at
least 99.99% for the non dioxin containing material and
99.9999% for dioxin containing waste. Other major operating
requirements are:
monitor carbon monoxide in the stack gas with the
level not to exceed the specified limit;
monitor waste feed rate;
monitor combustion temperature;
monitor excess oxygen;
monitor combustion gas velocity;
proper controls during start-up and shut-down opera-
tions;
maintain proper controls for fugitive emissions from
the combustion zone, including totally sealing the
combustion zone against fugitive emissions and main-
taining a combustion zone pressure lower than at-
mospheric pressure.
During implementation of this remedy, the soils will be
excavated and stored on the site a short time in a manner
which meets all relevant and appropriate storage elements
until they are fed through the thermal destruction unit.
Upon completion of the treatment, the soils would be
replaced onsite and covered with top soil and revegetated.
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No material will be shipped off site for disposal or require
onsite containment. Because thermal destruction removes all
the organic matter in the soil it may be helpful to add
organic matter, like straw, to the soil to encourage vegeta-
tive growth.
It is expected that all the wastes above the health based
treatment goals will be treated to below the health based
goals. As previously stated, the waste is not a RCRA waste,
therefore, the RCRA regulations on clean closure will not be
applicable, however, they are relevant and appropriate.
These regulations require that all waste residues and con-
taminated containment system components be managed as hazar-
dous waste. These should be removed and/or decontaminated
before the site remediation operations are completed.
Upon completion of this remedial action, the risk from the
treated soil will be reduced below IxlO"6 excess cancer
risk. Further degradation of the shallow ground water and
offsite contaminant migration would be eliminated. Fol-
lowing remediation, site deletion from the National Priority
List should occur, alleviating the need for institutional
controls.
Soil Alternative A-4
CHEMICAL TREATMENT AMD BACKFILLING
Present Worth: $ 34,600,000 - $48,400,000
Capital Cost: $ 34,500,000 - $48,300,000
Operation and Maintenance: $ 80,400
Years to Implement: 2-4
Excavate the soil and chemically treat.
Backfill treated soil.
Chemical treatment may involve solvent extraction or chemi-
cal dechlorination. Solvent extraction, which is a soil
washing technique, involves treating the excavated soil with
a solvent that preferentially dissolves absorbed substances.
Contaminants are transferred from the soil to the solvent.
Soil is separated from the solvent by gravity settling and
it is then dewatered. Clean solvent is recovered by distil-
lation. The spent solvent may require further treatment, on
or off the site. The treatment time is estimated assuming a
100 cubic yard/day treatment system. A concentrated liquid
containing an estimated 125,000 gallons would require off-
site incineration or on-site wet air oxidation.
Chemical dechlorination involves mixing excavated soil with
dechlorination agents that react with chlorinated dibenzo-
p-dioxin and other chlorinated compounds. The soil/reagent
mixture is heated to 30°C - 150 °C with mixing until the
reaction is completed. The soils are then washed with
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several rinses of water. A six cubic yard/hour capacity was
used to estimate the treatment time. The dechlorinated soil
can then be backfilled and the reagent is recycled for
reuse. Space and electricity are available to setup and run
the reactor tank. During implementation of chemical treat-
ment, a small soil storage pile may be necessary to allow
for constant feeding of the soil.
These are innovative technologies. Treatability tests have
shown that chemical treatment can remove polynuclear
aromatic hydrocarbons, pentachlorophenol, chlorinated diben-
zo-p-dioxin and dibenzofuran compounds from soils.
Treatability tests of the dechlorination process have been
conducted using site soils. Treatability tests for solvent
extraction has been conducted on similar soils with similar
contamination. The remediation goals established for Texar-
kana Wood Preserving facility were not consistently
achieved. Fine tuning the process may enable the process to
achieve the remediation goals. Pilot studies would be
necessary before remedial design could be possible. Because
it is unlikely these technologies will achieve the remedia-
tion levels, the risk remaining after implementing this
alternative may approach the 1x10 excess cancer risk.
This is higher than for alternative A-3 which will meet the
remediation goals.
The wastes on site are not RCRA waste, and the Land Disposal
Restrictions are not applicable. However, in the event the
wastes are listed after this document is written, but before
it is signed, this alternative will comply with the Land
Disposal Restrictions through a treatability variance under
40 CFR 268.44. This variance will result in the use of
chemical treatment to attain the Agency's interim "treatment
levels/ ranges" for the contaminated soil at the site. The
toxicity, mobility and volume of the contaminants are reduc-
ed through treatment by transferring the contaminants from
the soil to a concentrated liquid phase which would then be
treated off-site by thermal destruction.
It is not expected that all the hazardous wastes on the site
will be treated below the health based remediation goal.
Therefore, a "landfill" closure may be required. A cap
would cover the 77,000 cubic yards of residue from the
treatment process. RCRA regulations affecting landfill
closure require the site to be capped, with a final cover
designed and constructed to provide long-term protection of
human health and the environment through minimization of the
infiltration of liquids through the capped area and proper
maintenance of the integrity of the cap over time with main-
tenance. This type of closure anticipates that post closure
care and maintenance will be carried out at the facility for
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at least 30 years. It may not be possible to delete the
site from the National Priorities List.
soil Alternative A-5
SOLIDIFICATION AND BACKFILL
Present Worth: $ 8,800,000
Capital Costs: $ 8,400,000
Operation and Monitoring: $ 430,000
Years to Implement: 1
Excavate the contaminated soil and treat by solidifica-
tion process.
Backfill site with treated soil.
Solidification is a process which mixes cement, lime or
other kinds of binding materials with contaminated soil to
reduce the ability of the contaminants to leach out of the
soil into the surrounding environment. This technology will
increase the volume of the contaminated soil to be back-
filled. A 20% increase in volume is estimated.
Solidification has been used successfully many times on
hazardous waste sites and does comply with the Federal
environmental preference that contaminants be treated.
However, organic contaminants, like the material found on
the Texarkana Wood Preserving Site, are often difficult to
solidify. A treatability study technology was not performed
on this site, because the technology is a well known tech-
nology. A treatability study or pilot study would be neces-
sary to determine specific site parameters. Solidification
may need to be preceded by a technology to address the high
organic concentration in the site soil. Once the amount of
organic material is reduced, solidification is an effective
way to reduce the mobility of the remaining contaminants.
Because binding materials are added to the soil, an increase
in volume will occur. Design consideration should be given
to ensure none of the Days Creek flood storage is lost when
the soils are replaced.
The effectiveness of this alternative will be determined by
the Toxicity Characteristic Leaching Procedure (TCLP). In
compliance with the NCP, the concentration of each con-
taminant will be 90 to 99% reduction.
The excess cancer risk should be eliminated, because ex-
posure is eliminated.
Although the waste on site is not a RCRA waste, hazardous
wastes will remain on the site. Therefore, a landfill
closure may be relevant and appropriate. RCRA regulations
affecting landfill closure require the site to be capped,
with a final cover designed and constructed to provide long-
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term protection of human health and the environment through
minimization of the infiltration of liquids through the
capped area and proper maintenance of the integrity of the
cap over time with maintenance. This type of closure an-
ticipates that post closure care and maintenance will be
carried out at the facility for at least 30 years. It may
not be possible to delete the site from the National
Priority List. As previously stated, institutional controls
are not currently enforceable in the State of Texas and
therefore not considered.
Alternative A-6
BIOLOGICAL TREATMENT AND BACKFILLING
Present Worth: $ 6,400,000
Capital Cost: $ 6,300,000
Operation and Maintenance: $ 120,000
Years to Implement: 10
Treat excavated contaminated soil biologically
Backfill treated soil on site
Biological treatment uses bacteria to degrade organic com-
pounds in soil. These bacteria are naturally occurring in
the soil and are capable of degrading organic compounds into
water and carbon dioxide. The soils would need water,
oxygen and nutrients added to enhance the biological treat-
ment process. This alternative involves excavating the
soils, placing them in a treatment cell, treating the soil,
then backfill the treated material. This alternative as-
sumes 4,000 cubic yards will be treated at a time and can be
treated in 3 months. No onsite storage is anticipated.
This technology has been proven effective in destroying,
thereby reducing toxicity and volume of pentachlorophenol
and some of the polynuclear aromatic hydrocarbons. It has
not been demonstrated to achieve the remediation goals
established for the carcinogenic polynuclear aromatic hydro-
carbons and does not degrade the chlorinated dibenzo-p-
dioxin and dibenzofuran. Risk reduction, therefore, may
approach a IxlO"4 excess cancer risk. This technology may
be used in conjunction with other technologies to further
reduce the toxicity and mobility of the contaminants.
Treatability studies have not been done at the site for this
alternative. A treatability study will be necessary to
determine design parameters. The wastes on site are not
RCRA waste, and the Land Disposal Restrictions are not ap-
plicable. However, in the event the wastes are listed after
this document is written, but before it is signed, this
alternative will comply with the Land Disposal Restrictions
through a treatability variance under 40 CFR 268.44. This
variance will result in the use of biological treatment to
attain the Agency's interim "treatment levels/ ranges" for
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the contaminated soil at the site. If all the "treatment
levels/ ranges" are not met, this variance will result in
the use of biological treatment and solidification to attain
the Agency's interim "treatment levels/ranges" for the con-
taminated soil at the site.
Closure requirements will vary with each technology con-
sidered in conjunction with biological treatment. However,
it is likely that hazardous wastes will remain on the site.
Therefore, a "landfill" closure may be required. The volume
of material under the cap will depend upon the volume reduc-
tion afforded by biological treatment. RCRA regulations
affecting landfill closure require the site to be capped,
with a final cover designed and constructed to provide long-
term protection of human health and the environment through
minimization of the infiltration of liquids through the
capped area and proper maintenance of the integrity of the
cap over time with maintenance. This type of closure an-
ticipates that post closure care and maintenance will be
carried out at the facility for at least 30 years. It may
not be possible to delete the site from the National
Priority List. As previously stated, institutional controls
are not enforceable in the State of Texas and therefore not
considered.
Alternative A-7
OFFSITE THERMAL TREATMENT AND DISPOSAL
Present Worth: $ 191,200,000
Capital Costs: $ 191,200,000
Operation and Maintenance: $ 43,000
Years to implement: 5
Excavate the soil and transport to an offsite thermal
destruction facility.
Backfill site with clean fill
This alternative requires that the soil be excavated and
transported to an offsite thermal destruction unit. The
rate of excavation and transportation of contaminated soil
will be governed by off-site incinerator capacity, currently
2.5 tons/hour at the nearest facility. The cost and the
implementation time was based on transportation off site on
22 cubic yard dump trucks with an actual hauling capacity of
20 cubic yards. This calculates out to about 4,400 trucks.
On site storage of the contaminated soil is not expected.
The ash will disposed of compliant to relevant and ap-
propriate regulations. This alternative meets the Federal
requirement that mobility, toxicity, and volume be reduced
through treatment. However, since this alternative is
significantly more expensive than an equally protective
action, it could compromise EPA's ability to fund actions at
other sites. Therefore, the EPA does not favor this alter-
native. The risk that will remain on site after implement-
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ing this remedy is approximately IxlO"5. There are no
commercial facilities currently permitted to thermally
destroy dioxin.
It is expected that all the wastes above the health based
treatment goals will be removed and treated to below the
health based goals. Therefore, the RCRA regulations on
clean closure will be appropriate.
VIII. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
The nine criteria are categorized into three groups: Thres-
hold, primary balancing, and modifying. The threshold
criteria must be satisfied in order for an alternative to be
eligible for selection. The primary balancing criteria are
used to weigh major tradeoffs among alternatives. The
modifying criteria are taken into account after public
comment is received on the Proposed Plan of Action.
The nine (9) criteria used in evaluating all of the alterna-
tives identified are as follows:
Threshold Criteria
Overall Protection of Human Health and Environment addresses
whether or not a remedy provides adequate protection and
describes how risks posed through each pathway are eliminat-
ed, reduced, or controlled through treatment, engineering
controls or institutional controls.
Compliance with ARARs addresses whether or not a remedy will
meet all of the applicable or relevant and appropriate
requirements of other Federal and State environmental statu-
tes and/or provide grounds for invoking a waiver.
Primary Balancing Criteria
Long-term effectiveness and permanence refers to the mag-
nitude of residual risk and the ability of a remedy to
maintain reliable protection of human health and the en-
vironment over time once cleanup goals have been met.
Reduction of toxicity. mobility, or volume through treatment
is the anticipated performance of the treatment technologies
that may be employed in a remedy.
Short-term effectiveness refers to the speed with which the
remedy achieves protection, as well as the remedy's poten-
tial to create adverse impact on human health and the en-
vironment that may result during the construction and im-
plementation period.
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Implementability is the technical and administrative feasib-
ility of a remedy, including the availability of materials
and services needed to implement the chosen solution.
Cost includes capital and operation and maintenance costs.
Modifying Criteria
State Acceptance indicates whether, based on its review of
the RI/FS and Proposed Plan, the State concurs with, op-
poses, or has no comment on the preferred alternative.
Community Acceptance will be assessed in the Record of
Decision following a review of the public comments received
on the RI/FS report and the Proposed Plan.
A ranking of the comparative analysis for the soil remedial
alternatives is included (see Table 4). The symbolic rank-
ing is based on the narrative analysis that follows.
Analysis
Overall Protection. Thermal treatment (alternatives 3 and
7) would destroy the contaminants on site to below the
health based criteria, and thereby provides the most protec-
tion. Biological treatment (alternative 6) may achieve a
level of treatment comparable to chemical treatment. Com-
bining either of these two alternatives with solidification
would destroy and/or immobilize all site contamination and
offer overall protection of human health and the environ-
ment. However, waste would be left on the site. Biological
remediation will take considerably longer posing a longer
short term risk at the site. Solidification (alternative 5)
does not reduce the volume or toxicity of the waste to the
degree thermal treatment, biological treatment and chemical
treatment do. So solidification is not considered as
protective as the other treatment technologies. Because the
waste is not treated in the no-action and capping alterna-
tives, (alternatives 1 and 2) the degree of overall protec-
tion would be reduced. No-action is not protective and
therefore will not be considered in the other evaluations.
Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs). ARARs are the Federal and State
requirements that a selected remedy must meet. For
example,an ARAR may require certain restrictions for build-
ing in a flood plain. As previously discussed, this site
does not contain a "RCRA Hazardous Waste". Therefore,
although the RCRA regulations which regulate RCRA hazardous
wastes are not applicable, they may be relevant and
appropriate. Each alternative has been reviewed in the
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TABLE 4
Comparative Analysis of Soil Alternatives
Based on the Nine Criteria
Overall Protection;
Most Protective Alternative A-3, Thermal
Destruction
Alternative A-7, Offsite Thermal
Destruction
Alternatives A-4 and A-6, Chemical
and Biological Treatment
Alternative A-5, Solidification
Alternative A-2, Capping
Least Protective Alternative A-l, No Action
Compliance with ARARs;
All alternatives will comply with
the appropriate ARARs.
Long-term Effectiveness and Permanence;
Most Effective Alternatives A-3 and A-7, On and
Off site Thermal Destruction
Alternatives A-4 and A-6, Chemical
and Biological Treatment
Alternative A-5, Solidification
Alternative A-2, Capping
Least Effective Alternative A-l, No Action
Reduction of Toxicitv. Mobility, or Volume;
Most Reduction Alternatives A-3 and A-7, On and
Off site Thermal Destruction
Alternatives A-4 and A-6, Chemical
and Biological Treatment
Alternative A-5 Solidification
Least Reduction Alternative A-l and A-2, No Acticr.
and Capping
Short-term Effectiveness;
Most Effective Alternatives A-l, and A-2,
Action and Capping
Alternatives A-3, A-4, A-5, and A-
6, On site Thermal Destruct:
Chemical Treatment, Solidificat .
and Biological Treatment
Least Effective Alternative A-7, Offsite The:-
Destruction
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TABLE 4 Cont.
Comparative Analysis of Soil Alternatives
Based on the Nine Criteria
Implementabilitv;
Cost;
Simplest to
Implement
Hardest to
Implement
Least Costly
Alternative A-l, No Action
Alternative A-2, Capping
Alternative A-3, Thermal
Destruction
Alternative A-5, Solidification
Alternatives A-4, A-6 and A-7,
Chemical Treatment, Biological
Treatment and Offsite Thermal
Destruction
Alternative A-l, No Action
Alternative A-2, Capping
Alternative A-6, Biological
Treatment
Alternative A-5, Solidification
Alternative A-4, Chemical Treatment
Alternative A-3, On site Thermal
Treatment
Alternative A-7, Offsite Thermal
Treatment
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"Description of Alternatives " section of this document for
ARARs.
The "thermal destruction and backfilling" and "offsite
treatment" alternatives will meet all the ARARs. The com-
bination of chemical treatment or biological treatment and
solidification alternatives will also meet the ARARs
provided RCRA closure regulations are applied. Capping and
stabilization will comply with the ARARs appropriate to
these remedies.
Long-term Effectiveness and Permanence. The thermal
destruction alternatives would destroy all the contaminants
on the site to below the health-based criteria. The com-
bination of the chemical treatment, biological treatment,
and solidification alternatives will destroy and/or im-
mobilize all the contaminants on the site, providing a
permanent remedy. Chemical treatment or biological treat-
ment followed by solidification will require long term
maintenance of the stabilized material. Alternative A-2,
"capping" would eliminate the risks of direct contact and
the continued release of contaminants into the air but there
could be a continued release of the soil contamination into
the ground water. This remedy would also require long term
maintenance to insure the integrity of the cap.
Reduction of Toxicity, Mobility/ or Volume of the Con-
taminants Through Treatment. Alternatives 1, and 2 do not
meet the Federal preference that toxicity, mobility or
volume of the contaminants be reduced through treatment. As
previously mentioned, chemical treatment is as effective at
removing the contaminants from the soil as biological treat-
ment. Neither of these alternatives can achieve the level
of destruction thermal destruction does. Thermal destr-
uction destroys the contaminants above the health based
criteria, reducing mobility, toxicity and volume. Solid-
ification reduces the mobility of the contaminants but does
not reduce the toxicity, or the volume of the contamination.
Because a binding agent will be added to the soil in solidi-
fication, the actual volume of material that will be handled
increases.
Short-term Effectiveness. None of the alternatives pose
unacceptable short term risk. The surrounding community
will be properly protected during the implementation of
chemical treatment, thermal destruction, and chemical treat-
ment or biological treatment followed by solidification.
Air emissions produced by these technologies will be con-
trolled by a treatment system. 40 CFR Part 264, Subpart 0
specifically address the air emissions associated with
thermal destruction. Excavation of soils present the"poten-
38
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tial of air emissions. Dust control measures may be re-
quired during the excavation of the soil. The biological
treatment followed by solidification alternative will take
approximately eleven years as compared with approximately,
three to five years for chemical treatment followed by
solidification or two and a half for thermal destruction,
and one year for capping. Additional short term risks are
associated with transporting the waste offsite for treat-
ment.
Implementability. The combination of chemical treatment or
biological treatment and solidification, are considered
innovative technologies. They each would require large
scale pilot studies to determine design criteria. Both
technologies have been demonstrated effective at other sites
with similar wastes. However, these technologies have not
been demonstrated as consistently effective at destroying
this particular mixture of waste as thermal destruction has.
Chemical treatment and biological treatment will both re-
quire a longer design and shake down period than thermal
destruction because of the number of unknowns with these
processes. Capping is the easiest alternative to implement.
Thermal treatment, on or off site, are comparable based on
implementability, and easier to implement than chemical
treatment, biological treatment or solidification.
Cost. The estimated cost of the combination of biological
treatment followed by solidification is $15,000,000. This
can be compared to $43,000,000 for on-site thermal destruc-
tion, approximately $ 40,000,000 for chemical treatment, and
$190,000,000 for offsite thermal destruction. EPA believes
that when a remedial action would be significantly more
expensive than an equally protective alternative, it could
compromise EPA's ability to fund actions at other sites.
Therefore, offsite thermal destruction is not considered a
viable alternative.
State Acceptance. The State of Texas through the Texas
Water Commission has reviewed the Record of Decision. The
State supports EPA's selected remedy of onsite thermal
destruction.
Community Acceptance. Judging on the comments received
during the public comment period, the community supports the
thermal destruction technology. The preference for offsite
thermal destruction was voiced. All the comments received
during the public comment period and EPA responses are in
Appendix A.
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IX. DESCRIPTION OF ALTERNATIVES
Ground Water Remedial Alternatives
The alternatives for the ground water cleanup are the fol-
lowing:
Alternative B-l: Extraction, Treatment and Discharge
Alternative B-2: Extraction, Treatment, and Reinjec-
tion
Alternative B-3: Slurry Wall
Alternative B-4: No Action
Common Elements: Primarily, the ground water action will
occur after the soil portion of the remedial action has been
completed. The treatment process may need to be on the site
and operational during the soil portion of the remedial
action to treat any ground water encountered during the
excavation process.
This ground water discussion only addresses the shallow
ground water (to approximately 13.5 feet). The deeper zones
are still undergoing investigation and will be addressed in
a future Record of Decision. The EPA has classified this
shallow aquifer as a Class 2-B aquifer based on its poten-
tial for future use as a water supply. The remediation
levels are discussed in the "Summary of Site Risks" sec-
tion. Remediation goals are based on currently achievable
detection limits. The remedial investigation identified two
areas of ground water contamination, see Figure 6. These
areas are called "areas of attainment". There are ap-
proximately 16 million gallons of ground water outlined in
these areas of attainment. There are no surface impound-
ments which contain water that will need to be treated in
conjunction with the ground water. The location and number
of any wells needed in an extraction system will be deter-
mined during the remedial design.
All the ground water alternatives, except "No Action",
assume the contaminated soil is remediated. Soil remedia-
tion is the basis for the implementation time and cost. The
ground water in the shallow zone has a very low flow and
therefore, it will be difficult to maintain a constant
pumping rate.
With the exception of the "No Action" Alternative, all the
ground water alternatives require resampling of all monitor-
ing wells to determine current plume size and migration of
the plume, if any, since the completion of the remedial
investigation. Also required will be drilling soil borings
and installing shallow wells to determine if all the dense
non-aqueous phase is removed by the source control remedy.
Treatability studies are not necessary for the ground water
40
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treatment. However, in depth aquifer characterization is
necessary to determine well placement, which will maximize
pumping rate and minimize the pumping duration. Due to the
low yield of this aquifer, the ability of the pump and treat
system to effectively reach the remediation goal is uncer-
tain.
The goal of this remedial action is to restore ground water
to its beneficial use. However, studies suggest that ground
water extraction and treatment are not, in all cases com-
pletely successful in reducing contaminants to the remedial
goals in the aquifer. EPA recognizes that operation of an
extraction and treatment system may indicate the technical
impracticability of reaching the goals using this approach.
In the State of Texas, the water rights belong to the land
owner. As such, the State has no mechanism to prohibit use
of a stream, or ground water. Therefore, it is particularly
important that the ground water be remediated to protect
public health.
As with the soil, the waste in the ground water is not a
RCRA hazardous waste. The costs are estimates and within a
+50% to -30% degree of accuracy.
Ground Water Alternative B-l:
EXTRACTION, TREATMENT AND DISCHARGE
Present Worth: $ 4,300,000
Capital Cost: $ 3,100,000
Operation and Maintenance Costs: $1,200,000
Years to Implement: 15
Pump ground water from contaminated aquifer.
Treat ground water with carbon adsorption.
Discharge contaminated water.
This alternative would reduce site risk by substantially
decreasing ground water contamination present in the area
surrounding the site. Carbon adsorption is a process where
contaminants are removed from water by adsorbing onto carbon
in a treatment unit. The toxic materials are retained on
the carbon. The contaminants on the carbon can then be
thermally destroyed (on or off site), recycled or
landfilled. As the waste is not a RCRA hazardous waste, the
carbon is not considered a RCRA hazardous waste. Therefore,
disposal of the carbon compliant with RCRA hazardous waste
regulations is not applicable. This alternative meets the
Superfund preference for treatment of contaminants. This
alternative may be required to meet standards established
for National Pollutant Discharge Elimination System (NPDES)
or for a Publicly Owned Treatment Works (POTW).
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Alternative B-2:
EXTRACTION, TREATMENT, AND REINJECTION
Present Worth: $ 4,400,000
Capital Costs: $ 3,400,000
Operation and Maintenance Costs: $ 1,000,000
Years to Implement: 10
Pump ground water from contaminated aquifer.
Treat contaminated ground water on site by carbon
adsorption.
Reinject treated ground water in the aquifer.
Carbon adsorption is a process where contaminants are remov-
ed from water by adsorbing onto carbon in a treatment unit.
The toxic materials are retained on the carbon. As with the
previous alternative, the carbon can be thermally treated,
recycled or landfilled. Once treated, the water would be
reinjected into the ground. The advantage to reinjection is
that the pumping rate may be maintained. Through the carbon
treatment process, this alternative would reduce site risk
by substantially decreasing ground water contamination
present on the site. It would comply with Federal Superfund
preference for treatment of contaminants.
Ground Water Alternative B-3:
SLURRY WALL
Present Worth: $ 8,500,000
Capital Costs: $ 7,000,000
Operation and Maintenance Costs: $ 1,500,000
Years to Implement: .5
Install slurry wall barrier around the area containing
contaminated groundwater.
A slurry wall is a trench filled with materials that limit
the flow of ground water through the area surrounded by the
trench. A slurry wall would reduce site risk by minimizing
further migration of contaminants. This alternative would
not reduce the toxicity or volume of contaminants present in
ground water, and it would not meet the Superfund preference
for treatment of contaminants. This alternative could in-
crease downward migration of the contaminated water into
deeper zones. Since a slurry wall is a containment alterna-
tive, it will be necessary to waive the MCLs and Ambient
Water Quality Criteria ARARs.
Ground Water Alternative B-4
NO ACTION
This alternative assumes no action would be taken to prevent
migration of contaminated ground water at the site. The
costs associated with the alternative are listed in conjunc-
tion with Soil Alternative A-l. With this alternative,
42
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future use of contaminated ground water offsite could result
in unacceptable public health risks. Contaminants would
continue to adversely affect the surrounding environment.
X. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
The nine (9) criteria used in evaluating all of the alterna-
tives identified are as follows:
Overall protection of human health and the en-
vironment,
Compliance with applicable or relevant and ap-
propriate requirements,
Long-term effectiveness and permanence,
Reduction of toxicity, mobility, or volume
thorough treatment,
Short-term effectiveness,
Implementability,
Cost
State/support agency acceptance, and
Community acceptance.
A symbolic ranking of the comparative analysis for the
ground water alternatives are included (see Table 5). The
symbolic ranking is based on the narrative analysis that
follows.
Analysis
Overall Protection. Overall protection of human health and
the environment is provided by all of the alternatives
except "no action". Alternatives B-l and B-2 provide
protection because of treatment of ground water prior to
discharge or reinjection. Slurry walls, alternative B-3,
may not obtain the levels of protection alternatives B-l and
B-2 do. Alternative B-4 does not provide any protection to
human health and the environment.
Compliance with Applicable or Relevant and Appropriate
Requirements ARARs. ARARs are the Federal and State require-
ments that a selected remedy must meet. All of the ARARs
for Alternatives B-l and B-2 can be met. No treatment oc-
curs in Alternatives B-3 however as it is a containment
remedy, the MCLs and Ambient Water Criteria will be waived.
Short-term Effectiveness. During the construction of the
extraction wells, or excavation for the slurry wall, precau-
tions will be taken to eliminate any risk to the public from
excavation or installation of the wells. Ground water
remediation is scheduled to occur upon completion of the
soil remediation so air emissions from any action should not
constitute a threat. The estimated time required to
43
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TABLE .5
Comparative Analysis of Ground Water Alternatives
Based on the Nine Criteria
Overall Protection;
Most Protective Alternatives B-l and B-2,
Extraction, Treatment and Discharge
or Reinjection
Alternative B-3, Slurry Wall
Least Protective Alternative B-4, No Action
Compliance with ARARs;
Most Compliance Alternatives B-l, B-2, and B-4,
Extraction, Treatment and Discharge
or Reinjection and No Action
Least Compliance Alternative B-3, Slurry Wall
Long-term Effectiveness and Permanence;
Most Effective Alternative B-2, Extraction,
Treatment and Reinjection
Alternative B-l, Extraction,
Treatment and Discharge
Alternative B-3, Slurry Wall
Least Effective Alternative B-4, No Action
Reduction of Toxicitv. Mobility, and Volume;
Most Reduction Alternatives B-l and B-2,
Extraction, Treatment and Discharge
or Reinjection
Least Reduction Alternatives B-3 and B-4, Slurry
Wall and No Action
Short-term Effectiveness;
Implementabilitv!
Most Effective Alternative B-4, No Action
Alternatives B-l and B-2,
Extraction, Treatment and Discharge
or Reinjection
Least Effective Alternative B-3, Slurry Wall
Easiest to Alternative B-4, No Action
Implement Alternative B-2, Extraction,
Treatment and Reinjection
Alternative B-l, Extraction,
Treatment and Discharge
Hardest to Alternative B-3, Slurry"Wall
Implement
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Cost;
TABLE 5 Cont.
Comparative Analysis of Ground Water Alternatives
Based on the Nine Criteria
Least Costly Alternative B-4, No Action
Alternative B-l, Extraction,
Treatment and Discharge
Alternative B-2, Extraction,
Treatment and Reinjection
Most Costly Alternative B-3, Slurry Wall
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complete Alternatives B-l, B-2, and B-3 is 15 years, 10
years and one half a year respectively.
Long-term Effectiveness and Permanence. Alternatives B-l
and B-2 call for the removal and treatment of the con-
taminated ground water. The risk from ingestion of, or
direct contact with, the contaminated ground water will be
eliminated. The slurry wall cannot be considered a per-
manent remedy since no ground water treatment will occur and
downward migration will continue. The adequacy and reliabi-
lity of the pump and treat technologies have been well
proven, however, maintaining an adequate pumping rate may be
difficult considering the low ground water yield.
Reduction of Toxicity, Mobility, or Volume of the Con-
taminants through Treatment. Alternatives B-l and B-2 meet
the Agency's preference that the toxicity, mobility and
volume of the contaminants are reduced through treatment.
The treatment technology to be used for Alternatives B-l and
B-2 is carbon absorption. Carbon adsorption is well proven
and fully capable of removing the contamination from the
ground water. Alternative B-3 and Alternative B-4 do not
provide any reductions.
Implementability. Of the "action" technologies, Alter-
native B-3 has the shortest implementation time, followed
Alternative B-2 and finally by Alternative B-l. In many
cases, information may emerge during implementation and
monitoring of the ground water recovery system which strong-
ly suggests that it is technically impractical to achieve
the remediation levels throughout the area of attainment. A
contingency plan for the ground water remediation is dis-
cussed in the SELECTED REMEDY section of this document.
Cost. The cost of the alternatives are outlined in Table 6.
State Acceptance. The State of Texas through the Texas
Water Commission has reviewed the Record of Decision. The
State supports the EPA's decision of pumping and treating
the ground water.
Community Acceptance. Judging on the comments received
during the public comment period, the community supports th»
selected remedy of pumping, treating and reinjecting the
ground water. All the comments received during the public
comment period and EPA responses are in Appendix A.
XI. SELECTED REMEDY
Based on consideration of the requirements of CERCLA, the
detailed analysis of the alternatives, and public comment
the EPA has determined that soil alternative A-3: Thermal
46
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Destruction, and ground water alternative B-2: Extraction,
Treatment and reinjection are the most appropriate remedies
for the Texarkana Wood Preserving Superfund site in
Texarkana, Texas.
The remediation goals selected for the contaminated soils
and ground water are protective of human health and the
environment. They were selected to eliminate or reduce
risks associated with potential exposure to the con-
taminants via ingestion or direct contact with soil, sedi-
ments and sludges; and the ingestion of contaminated shallow
ground water. The goals call for the removal to concentra-
tions of:
SOIL:
Carcinogenic polynuclear aromatic hydrocarbons: 3 parts per
million as benzo(a)pyrene equivalents.
Total polynuclear aromatic hydrocarbons: 2450 parts per
million.
Chlorinated dibenzo-p-dioxin and dibenzofuran: 20 parts per
billion as 2,3,7,8 TCDD equivalents.
Pentachlorophenol: 150 parts per million
GROUND WATER:
Pentachlorophenol: 0.2 parts per million.
Carcinogenic polynuclear aromatic hydrocarbons: 10 parts
per billion as benzo(a)pyrene equivalents.
Chlorinated dibenzo-p-dioxin and dibenzofuran: .001 parts
per billion as 2,3,7,8 TCDD equivalents.
Approximately 77,000 cubic yards of soil, sediment and
sludges contaminated above these levels will be excavated.
The majority of this will be onsite and in the ponds. The
exception to this is in the southwest corner of the west
half of the site, where contaminated soil will be excavated.
Approximately 16 million gallons of contaminated ground
water will be pumped and treated.
Thermal destruction is the controlled combustion of organic
wastes. This is the complete destruction of the con-
taminants. Many types of thermal destruction units are
suitable for this alternative. Conventional thermal destru-
ction technology is capable of destroying organics in wastes
to very high efficiencies, typically in the order of 99.99
to 99.9999 percent, except when the toxic compound con-
centration in the feed is very low (Hazardous Waste In-
cineration. A Resource Document. January 1988, by The ASME
Research Committee on Industrial and Municipal Waste).
The ground water extraction system will pump the con-
taminated ground water from the shallow water (13.5 feet
48
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deep) bearing zone. The location and number of wells and
pumping rate will be determined during remedial design. The
treatment of the contaminated water using carbon absorption
technology is well proven. Absorption, in general, is the
process of collecting soluble substances that are in solu-
tion on a suitable interface. In this case the interface is
the between the ground water and the carbon. The carbon is
used to remove the dissolved organic matter. The carbon can
be regenerated easily in a furnace by oxidizing the organic
matter and thus removing it from the carbon surface, or
landfilling the carbon. Pretreatment of the ground water
may be necessary to remove suspended particles. This
pretreatment may consist of ferric hydroxide precipitation
and flocculation, followed by clarification and filtration.
As stated, the goal of this part of the remedial action is
to restore the ground water to a useable state, i.e., remov-
ing the organic contamination to the levels established in
the Safe Drinking Water Act and the Clean Water Act (MCLs
and AWQC). Based on information obtained during the
remedial investigation, and the analysis of all remedial
alternatives, the EPA and the State of Texas believe that
the selected remedy will achieve this goal. However,
studies suggest that it may not be possible to reduce con-
taminants to the remediation goals listed above, throughout
the area of attainment within the desired time-frame of 15
years. Ground water contamination may be especially persis-
tent in the immediate vicinity of the contaminants' source,
where concentrations are relatively high. The prac-
ticability of achieving cleanup goals throughout the site
cannot be determined until the extraction system has been
implemented and plume response monitored over time. If the
selected remedy cannot meet the health based remediation
goals, during implementation, contingency measures and goals
may replace the selected remedy and goals. These measures
are still considered to be protective of human health and
the environment, and are technically practicable under the
corresponding circumstances.
Both the selected remedy and the contingency remedy will
include ground water extraction, during which the system's
performance will be carefully monitored on a regular basis
and adjusted as warranted by the performance data collected
during operation. Modifications may include:
a) discontinuing operation of extraction wells in areas
where remediation goals have been attained;
b) alternating pumping at wells to eliminate stagnation
points; and
49
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c) pulse pumping to allow aquifer equilibration and
encourage adsorbed contaminants to partition into
ground water.
The contingency may be implemented under the following
conditions:
a) strong evidence of hydrogeologic conditions or the
presence of nonaqueous phase layers which seriously
calls into question the ability of ground water extrac-
tion and treatment technologies to achieve remediation
goals in portions of the aquifer;
b) contaminant levels have ceased to decline over time,
and are remaining constant at some statistically sig-
nificant level above health-base goals in portions of
the aquifer.
If one or both of these criteria are met during the design
or operation of the primary remedy, the contingency remedy
may be invoked.
If it is determined, on the basis of the preceding criteria
and the system performance data, that portions of the a-
quifer cannot be restored to their beneficial use, any or
all of the following contingency measures may occur as a
modification of the existing system:
a) ARARs may be waived for those portions of the a-
quifer based on the technical impractibility of
achieving further contaminant reduction.
b) low level pumping may be implemented as a long-term
gradient control, or containment measure,
The decision to invoke any or all of these measures may be
made during a periodic review of the remedial action, which
may occur at 5 year intervals. An Explanation of Sig-
nificant Differences will be issued to inform the public of
the details of these actions when they occur.
Statutory Determinations
Under its legal authorities, EPA's primary responsibility at
Superfund sites is to undertake remedial actions that achie-
ve adequate protection of human health and the environment.
In addition, Section 121 of CERCLA establishes several other
statutory requirements and preferences that the remedy
selected must meet. CERCLA 121 specifies that when com-
plete, the selected remedial action for this site must
comply with applicable or relevant and appropriate environ-
mental standards ("ARARs") established under Federal and
50
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State environmental laws unless a statutory waiver is jus-
tified. The selected remedy, also must be cost-effective
and utilize permanent solutions and alternative treatment
technologies or resource recovery technologies to the maxi-
mum extent practicable. Finally, the statute includes a
preference for remedies that employ treatment that per-
manently and significantly reduce the volume, toxicity, or
mobility of hazardous wastes as their principal element.
The following sections discuss how the selected soil and
ground water remedy -->et these statutory requirements.
Protection of Human He he Environment:
The selected soi" -otects human health and the
environment by e: -11 soils, sediment and sludges
contaminated abovt mediation goals, a IxlO"5 excess
cancer risk, and ti^. . jiiy destroying the contaminants.
Removing and destroying all the contaminated material above
the remediation goals will eliminate the threat of exposure
from direct contact, inhalation, or ingestion of the con-
taminated soils, and will prevent the migration of the
contaminants into the ground water. The remediated site
risk will be IxlO"6. The maximum risk at the site will be
IxlO"5.
The selected ground water remedy protect human health and
the environment by pumping ground water from the shallow
contaminated water bearing zone and then treating con-
taminated ground water by carbon adsorption. Following
treatment, the water will be reinjected in to the aquifer.
The current ground water monitoring system will be main-
tained or a new system designed to ensure that the remedial
action goals are being met and will be implemented.
The capture and treatment of the contaminated ground water
will eliminate threats of direct contact and ingestion posed
by the site. The current risks associated with these path-
ways are unacceptable. The target action levels are es-
tablished MCLs and detection limits for pentachlorophenol,
dioxin and polynuclear aromatic hydrocarbons. However, if
after monitoring the contaminant levels in the ground water
being pumped for treatment it appears that the remediation
goals cannot be met, a contingency may be invoked, as dis-
cussed in the SELECTED REMEDY section of this Record of
Decision. By maintaining a ground water monitoring program
in conjunction with the pump and treatment system, elimina-
tion of the threats posed by possible ingestion or direct
contact can be assured. There are no short-term threats
associated with the selected remedy that cannot be readily
controlled. Also, no adverse cross-media impacts are ex-
pected from the selected ground water remedy.
51
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Compliance with Applicable or Relevant and Appropriate Require-
ments:
Soil Remediation;
The selected soil remedy of excavation of pentachlorophenol,
polynuclear aromatic hydrocarbon, and dioxin contaminated
soils, thermal destruction and replacing the treated soil
will comply with all applicable relevant and appropriate .
action-, chemical-, and location-, specific requirements
("ARARs"). The ARARs are presented as follows:
Action-specific Soil Remediation ARARs:
As stated in the Alternatives Description Section, the
waste on site are not RCRA hazardous waste. According
all regulations which govern the disposal of waste are
not applicable, rather they may be considered relevant
and appropriate. Specific discussions about the ARARs
follow.
According to RCRA (Section 1004(34)), hazardous waste
thermal destruction units are considered treatment and
are, therefore, subject to several sections in Subtitle
C which address the problems of hazardous waste. The
40 Code of Federal Regulations (40 CFR) Part 264,
Subpart 0 addresses standards for the operation of
hazardous waste thermal destruction units. This
regulation is relevant and appropriate for this action.
This regulation governs applicability, waste analysis,
principal organic hazardous constituents (POHCs),
performance standard, hazardous waste permits and
operating requirements. Similarly, the proposed Stan-
dards for Owners and Operators of Hazardous Wastes
incinerators and Burning of Hazardous Wastes in Boilers
and Industrial Furnaces, Federal Register Friday, April
27, 1990 should be considered in the design and treat-
ment process.
RCRA land disposal restrictions (LDRs) established
under the Hazardous and Solid Waste Amendments, are not
considered applicable or relevant and appropriate. A
discussion how LDRs interact with the Texarkana Wood
Preserving site follows.
Because the waste onsite are not RCRA listed or
"characteristic" waste, the land disposal restrictions
are not applicable. The waste on site are soil and
debris, therefore, the land disposal regulations are
not relevant and appropriate.
Chemical-specific soil Remediation ARARs:
No chemical-specific soil remediation ARARs exist.
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Location-specific Soil Remediation ARARs:
Resource Conservation and Recovery Act (RCRA) require-
ments, 40 CFR 264.18, for location of a Treatment,
Storage or Disposal facility in a 100-year floodplain,
and also general requirements for the protection of
floodplains, 40 CFR 6, Appendix A as the site is within
the 100-year flood plain, these regulations are
relevant and appropriate.
Ground Water Remediation:
The selected ground water remedy of extraction and treat-
ment, followed by reinjection into the ground will comply
with all applicable or relevant and appropriate action-,
chemical-, and location-specific requirements (ARARs). The
ARARs are presented as follows:
Action-specific Ground Water Remediation ARARs:
Resource Conservation and Recovery Act (RCRA) require-
ments, 40 CFR 264.117(a) (1) Post-Closure and Monitor-
ing requirements for 30 years or another period deter-
mined by the Regional Administrator.
RCRA requirements, 40 CFR 264.190-198 may also apply.
RCRA requirements, 40 CFR 264.190-192, 40 CFR 268.601
treatment of hazardous waste in a unit.
Chemical-specific Ground Water Remediation ARARs:
The Safe Drinking Water Act (42 U.S.C. 300(f)) es-
tablished Maximum Contaminant Levels (MCLs, 40 CFR
141.11-141.16) for drinking water; (proposed at 0.2 ppm
for pentachlorophenol).
Requirements of the Clean Water Act (CWA) (33 USCA
1251-1376) specifically regarding 10"6 water quality
criteria (Carcinogenic polynuclear aromatic hydro-
carbons of 2.8 parts per trillion and Chlorinated
dibenzo-p-dioxin of 2.2xlO"4 parts per trillion)
Location Specific Ground Water Remediation ARARs:
RCRA requirements, 40 CFR 264.18 for location of a
Treatment, storage or disposal facility in a 100-year
floodplain, 40 CFR 6, Appendix A.
Cost Effectiveness:
The remedial action satisfies the threshold criteria set
forth in §300.430(f)(1)(iii) (A) and (B). The selected soil
remedy is cost effective because it will provide overall
effectiveness proportional to its cost, the net present
worth value being $43 million.
53
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The selected ground water remedy is also cost effective, its
present worth value being $ 4.4 million. The estimated cost
of the selected remedy is less than the cost associated with
installation of a slurry wall ($ 8.5 million) but are more
than the cost associated with directly discharging the
extracted ground water to a publicly owned treatment works
or discharging it into a surface body. It is believed the
reinjection will aid in the extraction process and is neces-
sary in obtaining the remediation goals.
Utilization of Permanent Solutions and Alternative Treatment
Technologies (or Resource Recovery Technologies) to the Maximum
Extent Practical:
EPA has determined that the selected soil and ground water
remedies represent the maximum extent to which permanent
solution and treatment technologies can be utilized in a
cost effective manner for source control and remediation at
the Texarkana Wood Preserving site. Of those alternatives
that are protective of human health and the environment and
comply with ARARs, EPA has determined that the selected soil
and ground water remedies provide the best balance of trade-
offs in terms of reduction of mobility, toxicity or volume
achieved through treatment, short term effectiveness,
implementability and costs, also considering the statutory
preference for treatment as a principal element and con-
sidering State and community acceptance.
The thermal destruction technology affords the most per-
manent and long-term effective solution to the contamination
problem posed by the Texarkana Wood Preserving Company site.
It is the proven and accepted method for the treatment of
dioxin contaminated waste. The other treatment technologies
investigated as possible remedies for the site were chemical
treatment and biological treatment. Neither of these tech-
nologies offer are proven in the destruction of the combina-
tion of contaminants that coexist on the site. Therefore,
the degree of permanence and protection that biological
treatment offers is not assured. The long-term effective-
ness of biological and chemical treatment has not been
proven.
In regard to short term effectiveness, when a thermal
destruction unit is operated at the designed temperature,
within the designed feed rate, provided with the appropriate
mixing, it will meet all the State and Federal requirements
and will be protective.
Thermal treatment is the accepted method for the treatment
of dioxin and is well proven for the destruction of the
other organics in the waste. The other alternatives have
been proven effective on certain parts of the contamination,
54
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but is not effective at remediating all the site contamina-
tion. A "treatment train" could be constructed to treat all
the contaminants using a number of the technologies. How-
ever, as more technologies are used on the site, the im-
plementation becomes considerably more complex, not to men-
tion more expensive. Thermal treatment provides no obvious
cost savings, however, it is in the same relative range as
the chemical treatment alternative, offering a greater
degree of certainty of remediation. Thermal treatment is
within the same order of magnitude as biological treatment
followed by stabilization, and offers more permanent treat-
ment. Cost is not a trade-off for protection.
The selected ground water remedy, satisfies the long-term
effectiveness and permanence, reduction of toxicity, mobili-
ty, or volume through treatment, and implement-ability
criteria better than all of the other alternatives inves-
tigated. It is slightly more expensive than discharging the
extracted ground water into a surface body or publicly owned
treatment works however, it offers a greater assurance that
pumping is implementable. The short-term risk associated
with the selected ground water remedy are composed of pos-
sible exposure of workers and the community to the ground
water treatment system, however, these potential risks are
easily controlled, therefore all but eliminated.
Preference for Treatment as a Principal Element:
Both the ground water alternative and soil, sludge and
sediment alternative use treatment as the primary remedia-
tion technology for the principle threat posed by source
material. Therefore, the statutory preference for remedies
that employ treatment as a principal element is satisfied.
XII. DOCUMENTATION OF NO SIGNIFICANT CHANGES
The Proposed Plan for the Texarkana Wood Preserving Company
site was released for public comment in July 1990. The
Proposed Plan identified Alternative A-3, Thermal Destruc-
tion followed by backfilling the treated soil and Alterna-
tive B-2, Extraction Treatment followed by reinjection of
the treated ground water, as the preferred alternatives.
EPA reviewed all written and verbal comments submitted
during the public comment period. Upon review of these
comments, it was determined that no significant changes to
the remedy, as it was originally identified in the Proposed
Plan were necessary.
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APPENDIX A
RESPONSIVENESS SUMMARY
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TEXARKANA WOOD PRESERVING COMPANY SITE
RESPONSIVENESS SUMMARY
The Community Relations Responsiveness Summary has been prepared
to provide written responses to comments submitted regarding the
Proposed Plan at the Texarkana Wood Preserving Company 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 Texarkana
Wood Preserving Company site.
Section II: Summary of Major Comments Received. The comments (both
oral and written) are summarized and EPA's responses are provided.
I. Background of Community Involvement and Concerns
The community of Texarkana is acutely aware of the problems
associated with the Texarkana Wood Preserving Company site.
This awareness is evident by the number of community
environmental action groups in Texarkana and the participation
of the County and City officials throughout the Remedial
Investigation and Feasibility Study. Judging by the comments
received the primary concern the residents of Texarkana
expressed during public comment was that thermal destruction
will cause adverse health affects to those who live in the
area.
II. Summary of Manor Comments Received
Public notice announcing the public comment period and
invitation to a public meeting was given on July 8, 1990 in
the Texarkana Gazette. The Proposed Plan fact sheet was
distributed on July 9, 1990. The comment period began on July
12 and ended on August 11, 1990. A public meeting was held
on July 24, 1990, at the City Hall Council Chambers in
Texarkana, Texas. The purpose of this meeting was to discuss
the proposed alternatives and the preferred alternatives.
Approximately 35 people were in attendance and 18 people asked
questions or made comments. Two letters were received with
comments.
The comments and questions received during the public comment
period follow.
1. Comment:
The volume of contaminated material mentioned in the Propose i
Plan and in the public meeting was 76,000 cubic yards. Ye»
in the cost calculations in the Feasibility Study, the costs
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are based on eighty-eight thousand cubic yards. Why is there
a difference?
Response:
The volume discussed in the Proposed Plan and at the public
meeting is the compacted volume of wastes. The volume of soil
used to determine the cost is based an expanded volume, 88,000
cubic yard. The volume is expected to expand as it is
excavated due to an increase of air in the noncompacted soil.
2. Comment:
How long will EPA Superfund activities onsite preclude
development of the property?
Response:
Remediation of the soil is expected to last two to three
years. Remediation of the ground water is expected to last
ten years beginning upon completion of the soil remediation.
The placement of the ground water extraction, treatment and
reinjection systems may preclude development of some parts of
the site during the ground water remediation. Therefore, it
is estimated that it will be twelve to thirteen years once the
remedial action has begun before development of the whole site
can occur.
3. Comment:
Are the dioxin concentrations mentioned in the Proposed Plan
and at the public meeting the 2,3,7,8-TCDD type of dioxin?
Was 2,3,7,8-TCDD found on the site?
Response:
The dioxin concentrations mentioned in the Proposed Plan and
in the public meeting was 2,3,7,8-TCDD equivalents. This
means that each type of dioxin was compared to the 2,3,7,8-
TCDD type, using the established EPA toxic equivalencies
guide, and an equivalent potency is calculated. Using this
method, the potency of the dioxin on site is all related to
the 2,3,7,8-TCDD type. A discussion of the equivalency
factors and the table listing these factors is in the Summary
of Site Risks section of the Record of Decision. Two samples
indicated that the 2,3,7,8-TCDD type dioxin is on site.
4. Comment:
Why can't we send the contaminated soil to Times Beach,
Missouri and burn it up there?
Response:
One of the alternatives evaluated during the Feasibility Study
was off site thermal destruction. In this evaluation, the
soil was excavated, trucked to a commercial incinerator. The
estimated cost of this alternative was $191 million, almost
400% more than the second most expensive alternative, and
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almost 450% the cost of on site thermal destruction. The
incinerator to be used at Times Beach will not be a Federally
owned facility, but a contract with a commercial firm.
5. Comment:
How often will air monitoring be done? How long does it take
to receive the analytical results from the air monitoring?
Response:
Instack monitoring is continuous and nearly instantaneous.
The stack monitoring is linked to the feed. Ultimately, when
stack monitoring detects emissions above preset limits, the
incinerator automatically shuts down. Ambient air monitoring
systems are used to evaluate the quantity and quality of dust
leaving the site from the excavation process, not air quality
problems generated by the incinerator.
6. Comment:
What permeability or leachability limits would be established
for the solidification of the waste?
Response:
The permeability will be determined by the Toxicity
Characteristic Leaching Procedure (TCLP). The established
limit of leachate concentration for pentachlorophenol is 100
parts per million. This concentration was in the Toxicity
Characteristic Rule. In the preamble to the NCP, the EPA
states that it expects to reduce contaminant mobility at least
90 to 99%.
7. Comment:
Why is the EPA spending money to remediate the Texarkana Wood
Preserving Company site? The money being spent on the
Texarkana Wood Preserving Co.site would be better spent on the
Koppers Texarkana site. No one lives on the Texarkana Wood
Preserving Company site, but many families live on the Koppers
Texarkana site.
Response:
Both the Texarkana Wood Preserving Company and Koppers
Texarkana site have been judged to present a long term threat
to human health and the environment. EPA is proceeding to
correct pollution problems at both sites; funding one site
does not jeopardize preceding with the other.
8. Comment:
City of Texarkana and Bowie County officials would like to
have the opportunity to comment on the contractor before the
contract is awarded.
Response:
The contractor for the remedial action will, by Federal law,
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be selected through open and competitive bidding. EPA will
provide local officials and residents with an opportunity to
understand the remedial design at various stages of
completion. However, it would be inappropriate for county
and city officials to select the contractor or to review and
comment on bidders to the project as it is outside the
requirements of Federal law.
9. Comment:
How will dust be controlled during the excavation of the soil?
How will runoff be maintained?
Response:
Generally, the best method of controlling dust emissions is
to spray the area being worked at frequent intervals (30
minutes to 2 or 3 hours). Water or a surfactant can be used,
and it can be sprayed from a mobile tower. Spraying moistens
the soil on the surface but not all the soil being move;
however, soil below the surface is frequently more moist than
soil on the surface. The surface spray reduces emissions from
dust. Ambient air monitoring will also occur. Runoff will
be controlled by diking the site area.
10. Comment:
Please explain the difference between "Present Worth Cost",
"Capitol Cost" and "Operational and Maintenance Cost".
Response:
The "Capitol Cost" is how much the setting up the equipment,
excavating the soil, running the process, and removing the
equipment from the site will cost. "Operational and
Maintenance Costs" are the costs associated with the site
after remediation is complete. These costs include .things
like maintaining a cap, leachate tests for a solidified mass,
and maintaining a fence around the site. "Present Worth
Costs" are the total of these two costs in today's dollar.
These calculations include an 8% inflation rate for 30 years.
11. Comment:
What is the Hazard Ranking System score of the site? What
year did the site go on the list?
Response:
The Hazard Ranking System number is 40.19. The site was put
on the list in 1986.
12. Comment:
What is the Hazard Ranking System score for the Koppers
Texarkana site?
Response:
The Hazard Ranking System number for the Koppers Texarkana
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site is 31.31.
13. Comment:
Is the highest score under the new criteria 28? Please
explain the new system. How is the system different than the
old system? What prompted the new system?
Response:
For a site to be proposed to the National Priorities List a
minimum score of 28.5 must be maintained under the Hazardous
Ranking System (HRS). In 1986, Congress passed the Superfund
Amendments and Reauthorization Act (SARA), Section 105 of
which requires EPA to amend the HRS to assure "to the maximum
extent feasible, that the HRS accurately assesses the relative
degree of risk to human health and the environment posed by
sites and facilities subject to review." EPA published
proposed revisions to the HRS on December 23, 1988 (53 FR
51962). While the general structure of the HRS continues to
be similar to the original HRS, the proposed rule constituted
a substantial revision of the HRS. Virtually every factor has
been revised and several new factors and threats have been
added. The major proposed changes include consideration of
potential releases to air, addition of mobility factors,
addition of dilution and distance weighing for the water
pathways, revisions to the toxicity factor, additions to the
list of covered sensitive environments, additions of human
food chain to the surface water pathway, revision of waste
quantity factor to allow for consideration of hazardous
evaluating population factors, and inclusion of an onsite
exposure pathway. The revised HRS continues to undergo
revision, and has not yet been finalized. Finalization may
occur in the Fall of 1990.
14. Comment: When was the potentially responsible party
investigation begun? Is it still ongoing? Who are the
potentially responsible parties? What is the status of these
companies? What is the status of the National Lumber and
Creosote Company? Are they considered the first operators at
the site? Who ran the Texarkana Wood Preserving Company?
Response:
The initial PRP investigation began in 1985. A revised PRP
search was begun in April, 1990 and is still ongoing.
Although some potentially responsible parties have been
identified, the investigation continues. The names and
statuses of potentially responsible parties are available
under the Freedom of Information Act request.
John T. Logan organized the National Lumber Company in 1903.
Between 1903 and 1923 Mr. Logan organized several companies
which became known as the "National Lumber & Creosoting
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Company". National Lumber & Creosoting Company, Inc.
incorporated, dissolved, and reincorporated several times in
Texas, Arkansas, and finally, Delaware. By 1938, the last
National Lumber & Creosoting Company dissolved. It is
presumed that the National Lumber & Creosote Company were the
first operators at the site.
The question of who ran the Texarkana Wood Preserving Company
and at what times is one of the focus' of the current
investigation.
15. Comment:
What effect would locating a viable responsible party have on
the site? Would the responsible party have the opportunity
to select another remedy?
Response:
All potentially responsible parties (PRPs) will be given the
opportunity to perform the remediation selected for the site.
The responsibility for selecting remedies is solely and
uniquely EPA's, not the responsible parties nor other parts
of the government. After the remedy is selected, the EPA is
required to provide an opportunity for the PRPs to implement
the remedy in the Record of Decision. The moratorium cannot
be used to negotiate a new remedy.
16. Comment:
Why are the PRPs selecting a new remedy at Koppers Texarkana?
Response:
They are not. EPA decided, based on an internal review of
creosote site action level, that the action level for the
residential portion of the Koppers site needed to be updated
to further protect human health. The PRPs had nothing to do
with this decision. The PRPs do not select remedies at
Superfund sites. Revising the action level will not alter the
overall approach intended for the selected remedy outlined in
the 1988 Record of Decision.
17. Comment:
Is the EPA holding Beazer responsible for the remediation of
Koppers Texarkana?
Response:
Yes. Beazer is the primary Responsible Party for the Koppers
Texarkana site.
18. Comment:
Who was charged with the responsibility of regulating and
monitoring the companies who operated at the Texarkana Wood
Preserving Company site?
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Response:
The site was the responsibility of the Texas Water Commission
and its predecessors, the Texas Department of Water Resources
and the Texas Water Quality Board.
19. Comment:
Who preformed the remedial investigation and feasibility study
at the Texarkana Wood Preserving Company site?
Response:
The State of Texas, under direction of the Texas Water
Commission, was the lead agency. The Texas Water Commission
contracted the remedial investigation and the feasibility
study out to Roy F. Weston Company, a consulting engineering
firm.
2 0. Comment:
When will the incineration process begin?
Response:
The tentative schedule for the remedial design and remedial
action is to begin design in February or March of 1991,
followed by the remedial action about 18 months to 2 years
later, in the fall or winter of 1992.
21. Comment:
Is the bid process competitive? Where will the advertisement
be run?
Response:
The bid process, as required by Federal law, is a free and
open competition bid when Federal funding is used. The
advertisement for the bid will be in the Commerce Business
Daily. For subscriptions write: Commerce Business Daily,
Superintendent of Documents, Government Printing Office,
Washington, D.C. 20302-9370, Telephone (202) 783-3238. The
advertisement may also be in the Texas Register. For more
information contact Roberta Knight in Austin (512) 463-5561.
22. Comment:
Where any inorganics found at the site? Where the
concentrations high?
Response:
Soil samples were analyzed for priority pollutant metals,
primarily to confirm that the chromium-copper-arsenic process
had not used at the Texarkana Wood Preserving site. With the
exception of mercury, most metal concentrations were below the
natural range. In most cases, mercury concentration exceeded
natural concentrations only slightly. However in three
samples, the mercury concentrations appear to be higher,
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although it is not wide spread. It is suspected the mercury
source is from a broken instrument, especially manometers or
thermometers, used in pressure cylinders. The concentrations
of mercury onsite do not pose a human health or environmental
risk.
2 3. Comment:
Was there any offsite migration of mercury?
Response:
No.
24. Comment:
Were there any heavy metals found in the ground water?
Response:
No.
25. Comment:
Will the pentachlorophenol, dioxin, furans, and polynuclear
aromatic hydrocarbons be removed from the ground water?
Response:
Yes. The pentachlorophenol will be removed down to the health
based criteria, the Maximum Contaminant Level (MCL). The
dioxin furans, and polynuclear aromatic hydrocarbons will be
removed down to below the detection limit.
2 6. Comment:
How will the carbon be treated after it has collected the
contaminants?
Response:
Generally, the carbon is thermally treated and the organics
are destroyed during the thermal treatment process.
27. Comment:
Has the equipment or vender for this process been selected?
Response:
No. The bidding process will be the same as that for the
remediation of the soil.
28. Comment:
How can we be certain the pentachlorophenol, dioxin and
polynuclear aromatic hydrocarbons will be destroyed in the
incineration process?
Response:
The EPA has experience in treating these types of wastes at
other sites, like Times Beach (Missouri), Love Canal (New
York), and Denney Farm (Missouri). The test burns completed
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at these sites indicated that the soils met all appropriate
goals. The trial burn at Texarkana Wood Preserving Co. site
will be required to have 99.9999% reduction of dioxin in the
stack emissions, and 99.99% reduction of pentachlorophenol and
polynuclear aromatic hydrocarbons in the stack emissions. The
soil will be required to be at, or below, the health based
criteria, and at least a 90% reduction of contamination. All
EPA's experience with the thermal destruction indicates it
provides protection of human health and the environment. For
this reason, incineration is considered the best demonstrated
available technology for the destruction of dioxin.
2 9. Comment:
What air emissions will be released from the stack during
operation?
Response:
The major constituents of incinerator stack gases are
nitrogen, carbon dioxide and water vapor. Other common
constituents found in lesser quantities -are carbon monoxide,
hydrochloric acid and unburned hydrocarbons. The major
constituents of the unburned hydrocarbons are low molecular
weight hydrocarbons like methane.
30. Comment:
Are there established incineration exhaust limits as there are
legally established drinking water limits?
Response:
Yes. One of the limits established for incineration is based
on percent reduction of the contamination (99.9999% for dioxin
and 99.99% for other hazardous organic constituents) in
addition emissions standards are based on the incinerator
design, particularly stack height. The trial burn will
establish other parameters that are related to emissions
(carbon dioxide, carbon monoxide, temperature, and chamber
time.
31. Comment:
Is there any other reliable technology for the treatment of
dioxin containing waste?
Response:
After years of research, EPA has not yet found an alternative
with the same effectiveness and reliability. Chemical
treatment to dechlorinate dioxin is theoretically possible by
our teste, to date, have shown it to cost as much or more as
incineration with less reliability. Tests conducted have
shown biotreatment to be effective in the foreseeable future.
Incineration is therefore the technique of choice for dioxin.
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32. Comment:
Is there any research going on to find an alternative to
incineration?
Response:
Yes, there is research to develop new alternatives to
remediate most all types of contamination. As mentioned in
question number 31, these include chemical dechlorination and
biological treatment.
3 3. Comment:
What will happen with the incinerator ash?
Response:
The ash will be tested for hazardous constituents. Once the
ash is proven not to have contamination above the health based
goals, it will be backfilled on the site. If the ash is still
found to contain hazardous material, it will be retreated.
If metal contamination is found, the ash will be placed in a
hazardous waste landfill, or solidified.
34. Comment:
Is an Environmental Impact Statement required for the
remediation process?
Response:
No, an Environmental Impact Statement is not required.
Superfund remedies are required to meet all applicable and
relevant and appropriate requirements, therefore, an
Environmental Impact Statement is not required.
3 5. Comment:
Has incineration been used at other dioxin contaminated sites?
Is there a report about how incineration has worked at these
other sites? How may I get a copy of the report?
Response:
Thermal destruction has been shown effective at Times Beach
(Missouri, Region 7), Love Canal, (New York, Region 2), and
Denney Farm (Missouri, Region 7). Copies of the reports IT. ay
be obtained from the EPA regional offices. Region 2, Jacc:
K. Javitz Federal Building, 26 Federal Plaza, New York, No-
York 10278. Region 7, 726 Minnesota Avenue, Kansas City, K
66101.
36. Comment:
Where any of these full scale incinerators?
Response:
Yes, a full scale incinerator was set up at Denney Farm.
10
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37. Comment:
Who will be financially liable for injuries, sickness, or
death by the air pollution caused by the incineration?
Response:
The built in monitoring system will not allow the incinerator
to operate outside the goals established health based goals,
therefore, injuries, sicknesses or death will not be caused.
Liability for damages which occur under government contracts
is determined by Federal statute. Although the State of Texas
is the lead agency in this action, the governing law will
still be Federal rather than State law. Congress included in
the Superfund statute provisions for contractor liability for
damages which occur during remedial actions, 42 U.S.C. § 9619.
Under normal conditions the contractor who is performing the
remedy will be responsible for damages done to foundations by
immediately adjacent excavation work, and can obtain insurance
to cover such a possibility. Whether or not the contractor is
found to be liable or whether liability may be born by the
United States or the State of Texas may rely, however, on the
application of the statute and on determinations of
negligence, gross negligence, or willful conduct on the part
of the contractor. These determinations may in turn be based
on whether the contractor is following the construction
specifications at the time the damage occurs. There is no
blanket indemnity by any party and liability will have to be
determined in each case according to the facts.
38. Comment:
How did the Texas Water Commission get selected as' the lead
agency for this site?
Response:
The Governor of Texas designated the Texas Water Commission
as the lead agency for Superfund activities in Texas.
3 9. Comment:
Can the incinerator be used to remediate both the Texarkana
Wood Preserving Co. site and the Koppers Texarkana site?
Response:
Incineration is not the selected remedy for the waste at the
Koppers Texarkana site. Therefore, incineration of the
Koppers Waste at the Texarkana Wood Preserving site has not
been considered.
4 0. Comment:
The costs for the remedies evaluated for the site appear t
be skewed in favor of a remedy that cannot assure destructi -
11
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of the most toxic constituents, biological treatment with
solidification of organics, and makes the most environmentally
protective option, incineration, appear to be far more
expensive than it actually is.
Response:
All the costs determined for the considered alternatives were
determined by the same technique and are therefore comparable.
All alternatives were evaluated in the same way. As stated
in the Record of Decision, the costs are estimated to be
within -30% to +50%. The primary criteria evaluated in the
selection of a remedy are overall protection to human health
and the environment and attainment of applicable or relevant
and appropriate regulations, not cost. It was, in fact,
thermal destruction rating of ability to achieve these two
primary criteria that prompted the Agency to select it as the
selected remedy.
41. Comment:
How often and how many years should the monitoring wells at
the Koppers Texarkana site be sampled?
Response:
The monitoring wells will be sampled during the Remedial
Action. The frequency and duration for sampling the ground
water will be determined during the Remedial Design.
42. Comment:
Will the vegetation on the Koppers Texarkana site ever be cut?
Response:
There are two separate areas of concern at the Koppers site,
they are: 1) the Carver Terrace subdivision, and 2) the
Kennedy Sand and Gravel pot area. The yards in the Carver
Terrace subdivision are maintained on a regular basis by the
residents. A maintenance program does not exist for the
Kennedy Sand and Gravel pit property. EPA has notified city
officials that this Agency has no objection to the City
maintaining the overgrown vegetation on this site. Since this
notification, EPA has been informed by a City official that
plans have been developed to maintain this area, and will be
implemented in the near future.
12
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APPENDIX B
THE STATE OF TEXAS, LETTER OF CONCURRENCE
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TEXAS WATER COMMISSION
B. J. Wynne, HI, Chairman
John E. Birdwell, Commissioner
Cliff Johnson, Commissioner
John J. Vay, General Counsel
Michael E. Field, Chief Hearings Examiner
Brenda W. Foster, Chief Clerk
Allen Beinke, Executive Director
September 25, 1990
Allyn M. Davis, Ph.D., Director
Hazardous Waste Management Division
U. S. Environmental Protection Agency
Region 6
1445 Ross Avenue
Dallas, Texas 75202-2733
Re: Texarkana Wood Preserving Company Superfund Site
Draft Record of Decision
Dear Dr. Davis:
We have reviewed the proposed Record of Decision (ROD) for the
Texarkana Wood Preserving Company Superfund site. We concur that the
selected remedy as described in the draft ROD of September 1990 is
the most appropriate for the site. The selected remedy calls for
treatment of contaminated soils by thermal destruction and for the
extraction, treatment, and reinjection of ground water. We
anticipate that state matching funds will be available to allow our
required assurance prior to a fund-financed remedial action.
Sincerely,
Allen Beinke
Executive Director
- .;-, !"iRi Nurtr. Congress Avc Aus:;". Texas 78711 30S7 Area Cucc 512 463 7831
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