PB95-963159
EPA/AMD/R04-95/253
March 1996
EPA Superfund
Record of Decision Amendment:
Helena Chemical Company
Landfill, Fairfax, SC
9/1/1995
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AMENDMENT TO THE
DECLARATION FOR THE RECORD OF DECISION
SITE NAME AND LOCATION
Helena Chemical Site
Fairfax, Allendale County, South Carolina
•STATEMENT OF BASIS AND PURPOSE
This decision document presents an amendment to the Record of
Decision for the Helena Chemical NPL Site located in Fairfax,
Allendale County, South Carolina, chosen in accordance with CERCLA,
as amended by SARA, and to the extent practicable, the National
Contingency Plan. This decision is based on the Administrative
Record for this Site.
The State of South Carolina concurs with the amendment to the
Record of Decision.
ASSESSMENT OF THE SITE
Actual and/or threatened releases of hazardous substances from this
site, if not addressed by implementation of the response action
identified in the Record of Decision (ROD), and as amended by this
amendment, may present an imminent and substantial endangerment to
public health, welfare, or the environment.
DESCRIPTION OF THE REMEDY
This amendment addresses the treatment technology and remedial
alternative for the treatment of contaminated soils at the Helena
Chemical Site. Contaminants include various pesticides, volatile
organic chemicals and metals. The major components of the remedy
as described in the September, 1993, Record of Decision are:
Extraction and treatment of contaminated ground water.
extraction will be performed by extraction wells completed in
the Barnwell Formation, a vClass IIB ground water underlying
the site. Treatment will be by means of carbon adsorption.
Discharge of treated ground water to the local POTW in
accordance with the pre-treatment requirements of that
facility.
Excavation and treatment of waste materials and contaminated
soils that exceed the remedial goals identified in Table 1.
Treatment will be by means of a combination of hydro-
lytic/photolytic dechlorination and biological treatment.
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Mitigation of the biological effects of contaminated sediments
found in the wetlands adjacent to the site by the restoration
or creation of suitable additional wetland habitat.
Replace all remediated soil on-site.
This amendment will change the treatment technology for
contaminated soils from on-Site hydrolytic/photolytic
dechlorination, and bioremediation, to off-Site incineration at a
RCRA-approved incinerator located in Clive, Utah. All other
requirements of the September, 1993, Record of Decision are
unaffected and remain in full effect.
STATUTORY DETERMINATIONS
The selected remedy as amended is protective of human health and
the environment, complies with Federal and State requirements that
are legally applicable or relevant and appropriate to the remedial
action, and is cost-effective. This remedy utilizes permanent
solutions and alternative treatment (or resource recovery)
technologies to the maximum extent practicable and satisfies the
statutory preference for remedies that employ treatment that
reduces the toxicity, mobility, or volume of the waste materials
and contaminated media. The remedial action will be reviewed after
a period of five years in order to evaluate the long-term
effectiveness and practicability of the remedial action.
<\6
Richard D. Green Date
Associate Director
Office of Superfund and Emergency Response
Waste Management Division
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AMENDMENT TO THE RECORD OF DECISION
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
DECISION SUMMARY
HELENA CHEMICAL SUPERFUND SITE
FAIRFAX. ALLENDAT.R rnnwPY. SOUTH CAROLINA Page 1
1. 0 INTRODUCTION
This Amendment to the Record of Decision describes a change in the
treatment alternative for contaminated soils and waste materials at
the Helena Chemical Superfund Site (the Site). The original Record
of Decision (ROD) was signed by the Regional Administrator on
September 8, 1993. The remedial alternative for contaminated soils
and waste materials specified in the ROD consisted of
hydrolytic/photolytic dechlorination (HPD), a process by which the
pesticide contaminants at the Site could be rendered less toxic.
All soils and wastes contaminated to levels which exceed 50
milligrams/kilogram (mg/kg) total halogenated pesticides were to
have been excavated and treated by this process. Since the HPD
process is an innovative technology, a contingency soil treatment
technology was included in the ROD. This contingency treatment
technology was specified to be low temperature thermal desorption
(LTTD). LTTD was to have been implemented should it be shown by
treatability studies that the HPD technology was not capable of
achieving the treatment performance standards specified in the ROD.
Treatability studies have shown that HPD will not achieve the
performance standards specified in the ROD. Additionally, a
treatment technology that is less costly than LTTD, and yet is
fully protective of human health and the environment, has been
identified. That treatment technology is off-Site incineration at
a permitted RCRA incinerator located in Clive, Utah. This ROD
amendment therefore changes the specified remedy for contaminated
soils and wastes from HPD (with LTTD as a contingency) to off-Site
incineration. All other provisions of the September 8, 1993, ROD
issued by EPA not inconsistent with the ROD amendments included
herein remain in full force and effect.
2.0 SITE LOCATION AND DESCRIPTION
2.1 SITE LOCATION
Helena Chemical Company, Fairfax, South Carolina is located on 13.5
acres adjacent to Highway 321 in Allendale County, South Carolina.
Located at the facility is a former landfill which contains
pesticide residues and other waste materials generated on-Site.
The former landfill occupies approximately four (4) acres on the
northeast portion of the Fairfax property. The site is encircled by
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2
a chain link security fence topped with barbed wire. A city water
well that is utilized by a population of approximately 2,300 is
located 200 feet west of the property.
2.2 SITE DESCRIPTION ;.
Three buildings exist on the Fairfax property; the north warehouse,
the office, and the south warehouse. The north warehouse, which
was once utilized to house the liquid insecticide formulation
operation, is currently used to store various pesticides,
herbicides, and fertilizers which are sold to farmers. There are
several significant features of the liquid formulation building
which were focal points of the investigation. Two 22,000 gallon
above ground solvent tanks were once located near the north
entrance to the "kettle room" in the former liquid formulation
building. These tanks were present prior to Helena's occupancy of
the property. Solvents used in the formulation process were
delivered to the site by rail car via a rail spur which was used to
serve the facility. The solvents were offloaded by' pressurizing
the tanker cars and pumping the solvents through product lines
which ran under the formulation building to the storage tanks. The
solvents were then gravity fed to the kettle as needed. The
solvent tanks are no longer present; however, the concrete slab on
which the tank saddles rested still exists. The remains of a tank
farm which was used to store the technical grade pesticide
compounds are located on the east side of the liquid formulation
building. Only the concrete pads on which the tanks rested and a
retaining wall remain. During the Remedial Investigation (RI) a
drain pipe which originates inside the warehouse was observed and
is suspected to have been used to discharge effluent onto the
ground surface in an area northwest of the structure. The south
warehouse where powdered insecticides were formulated is no longer
in use. A septic tank system which serviced the property is
located between the north liquid formulation building and the
office. Located northwest of the north warehouse are the remains
of a house that burned sometime prior to 1988. The house belonged
to the previous property owner, Charles Blue.
According to City of Fairfax Water Department records, a 12" water
main constructed of cast iron extends across the site between the
north warehouse and the former landfill. The water line trends in
a general east-west direction and is reported to have been
installed approximately ten years ago.
2.3 Site History
Between the years of 1971 and 1978, Helena used the Fairfax
facility for the formulation of liquid, and some dry, agricultural
insecticides. Prior to the ownership by Helena Chemical Company
(beginning in 1971), two other chemical companies operated at the
Fairfax facility: Atlas Chemical Company, owned by Billy Mitchell
(prior to the mid 60's), and then Blue Chemical Company, owned by
Charles Blue (mid 60's through 1971). Both Atlas Chemical Company
and Blue Chemical Company utilized the Fairfax facility for the
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formulation of insecticides. Chemicals formulated and/or stored at
the facility prior to Helena's ownership include: DDT, aldrin,
toxaphene, disulfoton, dieldrin, chlordane, BHC (benzene
hexachloride), and ethoprop (Mocap). The Fairfax facility is
presently being operated as a retail sales outlet and warehouse for
agricultural chemicals. Chemicals used in the previous formulation
of insecticides by Helena at the Fairfax facility include:
toxaphene, methyl parathion, EPN (ethyl p-nitrophenyl
thionobenzene-phosphonate), and disulfoton. In producing the
insecticides, the chemicals were formulated as mixtures with other
ingredients including diesel fuel, aromatic solvents, and clays.
2.4 Explanation of Fundamental Remedy Chancre
The 1993 ROD specified on-Site treatment of contaminated soils and
waste materials as the means to remove and/or destroy pesticide
contaminants by one of two treatment technologies. The first was
hydrolytic/photolytic dechlorination, or HPD. By this technology,
the chlorine atoms on the various Site-specific pesticides would be
removed by natural processes, using the energy available in
sunlight and mediated by microorganisms in the soil. The
performance standards specified in the ROD were based on the Land
Disposal Restrictions established in regulations promulgated under
the authority of the Resource Conservation and Recovery Act (RCRA).
Since HPD was considered to be an innovative technology that had
not been proven effective at achieving these performance standards,
a contingency remedy for contaminated soils was included in the
ROD, to be implemented should it be shown that HPD could not
achieve the performance standards. That contingency remedy was low
temperature thermal desorption (LTTD). The use of LTTD at other
Superfund sites where similar pesticide contamination was present
had been demonstrated to be effective at achieving the Land
Disposal restriction requirements.
Treatability studies have shown that HPD is unlikely to be able to
achieve the performance standards contained in the ROD.
Additionally, it has been determined that using off-Site
incineration, rather than on-Site LTTD, as the soil treatment
technology will be fully effective at meeting all performance
standards contained in the ROD, fully protective of human health
and the environment, and can be implemented at much less cost. The
fundamental changes to the remedy selected in the original ROD are
therefore changing the location of the remedy from on-Site to off-
Site, and changing the technology from HPD (or LTTD as a
contingency) to incineration at a permitted RCRA incinerator.
3.0 ENFORCEMENT ANALYSIS
Several companies have operated pesticide formulation facilities on
the Site currently owned by Helena. Prior to the mid-60's, the
Site was owned by Atlas Chemical Company, and from the mid-60's
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until 1971 by Blue Chemical Company. Between the years 1971-1978,
Helena Chemical company used the Site for the formulation of both
liquid and dry agricultural insecticides. Chemicals that have been
stored and/or formulated at the facility during its active life
include DDT, aldrin, toxaphene, disulfoton, dieldrin, chlordane,
benzene hexachloride (BHC), ethoprop, methyl parathion and ethyl p-
nitrophenyl thionobenzene-phosphonate (EPN). During the
formulation process these chemicals were mixed with carrying agents
including diesel fuel, volatile organic chemicals and adsorbent
materials.
The first regulatory actions taken with respect to the Helena Site
occurred in November, 1980, as a result of reports by a former
employee of Helena and a newspaper reporter that a waste dump was
being operated on the Site. The Site was investigated at that time
by the South Carolina Department of Health and Environmental
Control (SCDHEC). Numerous soil samples were collected and
analyzed in December, 1980. High levels of various pesticides,
including aldrin, BHC isomers, chlordane, dieldrin, disulfoton,
endrin and toxaphene were detected in these samples. As a result
of these findings, SCDHEC requested that Helena provide further
information regarding activities at the Site, including chemicals
handled as part of the operation, waste disposal practices and
other pertinent information with respect to past and present Site
activities.
SCDHEC issued a Notice of Violation to Helena in July, 1981, for
the operation of a waste disposal facility in violation of
applicable South Carolina regulations. Negotiations between SCDHEC
and Helena resulted in the issuance of Administrative Consent Order
No. 81-05-SW on October 1, 1981. In compliance with the terms of
this Consent Order, Helena conducted investigations at the Site
lasting from October, 1981, to July, 1982. The results of these
studies indicated that surficial soils were heavily contaminated
with pesticides, including those identified in the earlier sampling
described above. The results of analyses of ground-water samples
obtained as part of this investigation were contradictory; the
positive results reported from the first sampling event were not
confirmed in samples taken at that time or in subsequent sampling
events. Surface water samples, taken from water standing in the
wetland areas in the northern portion of the Site, were found to be
heavily contaminated with site-related pesticides.
Heleria prepared a plan for site remediation which was submitted to
SCDHEC for review, and, under the terms of an amendment to
Administrative Consent Order No. 81-05-SW, dated March 12, 1984,
remediation efforts were conducted that consisted mainly of the
removal of contaminated soils to a permitted hazardous waste
landfill.
In 1985, EPA, in conjunction with SCDHEC, conducted a Site
Screening Investigation at the Helena Chemical Site in order to
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prepare a Hazard Ranking System (HRS) package for the Site in order
to determine whether the Site should be included on the National
Priorities List (NPL) . The HRS ranking was completed in June,
1987, and the Helena Site was proposed for listing in June, 1988.
The Site was listed on the NPL in February, 1990.
In April, 1989, an Administrative Order by Consent (AOC) was
jointly developed, negotiated and agreed to by EPA and Helena
Chemical Company. Under the terms of this AOC, Helena agreed to
conduct a Remedial Investigation (RI) and Feasibility Study (FS) at
the Site under the oversight of EPA. The purpose of the RI/FS
process was to develop an appropriate remedy for the Site as
required by the National Contingency Plan (NCP). Helena retained
the services of Environmental Safety and Designs, Inc. (ENSAFE), of
Memphis, Tennessee as their contractor to conduct the RI/FS. RI
field activities began in May, 1989, and were completed in April,
1992.
Two removal actions for contaminated soils have taken place at the
Site. In addition to the removal of approximately 500 cubic yards
of contaminated material conducted by Helena in March, 1984, as
discussed above, in April, 1992, approximately 1000 cubic yards of
contaminated soils were also removed by Helena under the oversight
of EPA and likewise transported to a secure hazardous waste
landfill.
4.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
Initial community relations activities at the Helena Chemical NPL
Site included development and finalization of the Community
Relations Plan in December 1989. An information repository was
established at the Fairfax City Hall in January 1990.
A "kickoff" fact sheet announcing the start of the RI/FS was issued
in April 1990. On April 19, 1990, EPA held a public meeting at the
Fairfax Community Center to present the Agency's plans for the
RI/FS. The meeting was attended by several local citizens,
representatives of Helena Chemical, elected local officials and was
covered by local newspapers. EPA's presentation to the public
included information on how to participate in the investigation and
remedy selection process under Superfund. At the meeting, several
questions were asked and a fair amount of interest was expressed by
the community.
Following completion of the FS, a second public meeting was held on
May 27, 1993, to update the public on the RI findings to date, and
to present the proposed plan for the remedial actions at the Site.
The meeting was attended by only a few members of the public, with
no press coverage. At this meeting, the primary concerns expressed
by the public involved the threat posed by contaminated ground
water to the nearby public supply well.
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Proposed Plan fact sheets were distributed on May 18, 1993. An
advertisement was published in two of the local newspapers on the
same date. Both the advertisement and the fact sheet highlighted
the Public Comment period extending from May 18, 1993, until June
17, 1993. :
At the Proposed Plan public meeting on May 27, 1993, EPA presented
the Agency's selection of Preferred Alternatives for addressing
soil, sediment, surface water and groundwater contamination at the
Site.
5.0 SUMMARY OF CURRENT SITE STATUS
The RI investigated the nature and extent of contamination on and
near the Site, and defined the potential risks to human health and
the environment posed by the Site. A supporting RI objective was
to characterize the Site-specific geology and.hydrogeology. The
main portion of the RI was conducted from May 1989 through April
1992.
5. 1 NATURE AND EXTENT OF CONTAMINATION
Environmental contamination at the Site can be summarized as
follows:
1) Organic and inorganic constituents of concern have been
identified in the various media. The primary
constituents of concern at the Site include: aldrin,
alpha-BHC, beta-BHC, delta-BHC, gamma-BHC, DDT, ODD, DDE,
dieldrin, endosulfan, endrin, endrin ketone, toxaphene,
endosulfan sulfate, disulfoton, benzene, lead and
chromium.
2) Surface and subsurface soils throughout the Site have
been affected by past waste disposal activities. The
highest levels of contamination are found in the vicinity
of the former liquid formulation building now used as a
warehouse, in the vicinity of the old landfill, and near
the southernmost building on the Site in an area where
transhipments of materials from railroad cars occurred.
3) Ground waters in the aquifers immediately underlying the
Site have been affected by waste disposal activities at
the Site. The ground waters underlying the Site are
considered to be Class IIB ground waters under the draft
EPA Guidelines for Ground-Water Classification,
indicating that they are a potential source of public
water supply. These ground waters are also classified as
Class GB ground waters under South Carolina regulations.
The ground water has been contaminated to levels that
render it a threat to public health should it ever be
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used for potable water supply and which exceed state
ambient standards for Class GB ground waters. Ongoing
sampling has to date revealed no site-specific
contamination in the nearby municipal water supply well.
4) High levels of contamination remain in soils and waste
materials in the old landfill located in the northern
portion of the Site. These soils and waste materials are
likely to be a continuing source of ground-water
contamination.
5) Surface water and sediments in on-site wetlands and
drainage pathways have been affected by past waste
disposal activities. Pesticide concentrations in samples
taken from on-site surface waters exceeded criteria that
are protective of aquatic life. Sediments in the on-site
wetland areas were found to be contaminated with site-
related pesticides at levels that are likewise likely to
have an adverse impact on indigenous aquatic life.
6) Background and on-site air sampling indicates that local
ambient air has not been affected by past waste disposal
activities.
5.2 Surface and Subsurface Soils
The results of the field investigation identified varying
concentrations of polychlorinated pesticide compounds and minor
quantities of volatile organics in shallow surface soils (0 to 3
feet) . Soils from the 1 to 3 foot interval would normally be
considered shallow subsurface soils; however, for purposes of this
discussion soils from 0 to 3 feet will be referred to as surface
soils. Surface soils were collected employing hand augering
techniques as previously described.
In addition to surface soil samples, ten soil borings were
completed utilizing hollow stem auger techniques. Soil samples
were collected for analysis from the surface, and from just below
the interface of the vadose and saturated zones. Analytical
results from some deep soil boring samples have indicated elevated
levels of chlorinated pesticides.
5.2.1.1 VOCs in Soils
Soil samples collected throughout the RI have identified relatively
low levels of various volatile organic chemicals (VOCs). The most
commonly detected were acetone and methylene chloride; however, the
data validation review suggests that these and some other
contaminants may be laboratory artifacts. Two other chlorinated
solvents were identified in soil samples, tetrachloroethylene
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(PCE), and trichloroethylene (TCE), although the TCE detected in
two samples is believed to be a laboratory artifact. In addition,
the aromatic solvents, benzene, toluene, ethylbenzene, and xylene
were identified. Xylene is considered to be directly related to
the formulation process.
5.2.1.2. Semi-Volatiles in Soils • •
Although no semi-volatile compounds were confirmed in soils during
the Data Validation report three tentatively identified compounds
(TIC's) were recognized: disulfoton, chlorobenzilate, and
butylphosphorotrithioate. Levels of disulfoton ranged from 60 ppb
- 430,000 ppb and were identified in four percent of the soil
samples collected. Butylphosphorotrithioate was detected in three
samples at a concentrations ranging from 750 to 7900 ppb.
Chlorobenzilate was not detected in samples collected by ENSAFE,
but was identified in one split sample collected by the EPA
oversight contractor. Disulfotone sulfone was identified in one
sample at 51 ppb. Disulfoton sulfone is a degradation product of
disulfoton.
5.2.1.3 Pesticides in Soil
Soil samples collected during the RI have indicated a varied
distribution of individual pesticide components. Concentrations
for total pesticides range from below detection limits to 7170
mg/kg in surface and shallow subsurface soils. For the purpose of
total pesticides, the values indicated represent the summation of
all pesticide components identified during the RI. The primary
pesticide constituents identified were DDT (and its degradation
products), toxaphene, and BHC (including isomers). '• Contaminant
distribution data have been generated for the primary constituents
identified on the property. Those components comprising a less
significant fraction of the total pesticides identified include
aldrin, chlordane (including isomers), dieldrin, endrin, endrin
ketone, total endosulfans, heptachlor, heptachlor epoxide, and
methoxychlor.
The most significant levels of pesticides identified on the site
were found immediately north, northwest, and/or east of the north
warehouse. The overall levels of contamination generally show a
decrease in concentration with depth from the surface to three feet
below grade. Isolated "hot spots" however, show an increase in
concentrations at the one to two foot interval with subsequent
decrease in concentration again with depth.
5.3 Ground Water
A total of 22 monitoring wells were installed at the Fairfax site
during the RI. Thirteen wells were completed as shallow monitoring
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wells and nine wells were completed as deep monitoring wells. All
wells were completed within the upper Eocene aquifer system. The
installation and subsequent sampling of wells during Phase III of
the RI corresponded with the third quarter sampling event of 1991
for the wells installed during Phase II-A.
Chlorinated pesticides and volatile organics were identified in
samples collected from on-site shallow monitoring wells. One deep
well (MW-3) also indicated low levels of pesticides in ground
water. Endosulfan sulfate was detected in MW-5; however, the
quantity was "j" flagged. Four metals were detected in various
wells at concentrations above their respective MCLs and are
discussed below.
The City of Fairfax municipal well (south well) was sampled during
Phases II-A and III of the field investigation. Samples were
collected both before and after treatment by a chlorination
process. No Site-related contaminants were identified in any of the
samples collected from the municipal well samples. The north well
field, which is located approximately one mile north of the Site,
was not sampled.
5.4 Surface Water and Sediments
Sediments in the wetland areas located in the northern portion of
the Site were found to be contaminated with semivolatile chemicals
and pesticides. There are no chemical-specific ARARs for
sediments, but the levels of contamination found in the RI exceed
concentrations that have been shown through toxicological research
to have an adverse impact to aquatic life due to toxic effects of
these contaminants. This research is summarized in the National
Oceanographic and Atmospheric Administration (NOAA) publication
entitled The Potential for Biological Effects of Sediment-Sorbed
Contaminants Tested in the National Status and Trends Program, NOAA
Technical Memorandum NOS OMA 52, August, 1991. The pattern and
distribution of contamination in the sediments indicate that the
primary source of contamination is the landfill that was placed
partially in the jurisdictional wetlands. Sediment contamination
also extends into off-site drainage pathways for surface waters.
The sediment contamination found in both on-site and off-site
locations poses an unacceptable risk to environmental receptors.
On-site surface waters were found to have been contaminated with
pesticides at levels which exceed Ambient Water Quality Criteria
(AWQC) for the protection of aquatic life. Federal AWQC have been
established under the authority of Section 303 of the Clean Water
Act for the purpose of establishing protective guidelines for
ambient water quality. AWQC as developed by EPA are identified in
Section 121 of CERCLA as amended by SARA as chemical-specific ARARs
for NPL sites. In addition, the AWQC have been adopted by the
State of South Carolina as ambient surface water quality standards,
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and are therefore ARARs for the Site. The surface water
contamination identified as part of the RI also poses an
unacceptable risk to environmental receptors in the on-sdte wetland
areas and in drainage pathways leading off-site.
6.0 SUMMARY OF SITE RISKS
A Baseline Risk Assessment was conducted to evaluate the risks
presented by the Helena Chemical Superfund Site to human health and
the environment, under present day conditions and under assumed
future use conditions. Currently, there are no residents living on
the Site and only a few residents residing close to the Site.
There are no potable water supply wells on the Site, although there
is a municipal water supply well located less than one-quarter mile
away. Information gathered from census data regarding population
trends in Allendale County and surrounding areas suggests that
future land use will remain commercial and industrial, with little
potential for residential use of groundwater as a potable water
source. The Site was evaluated, however, under residential
exposure scenarios, including exposure pathways involving the use
of shallow ground water as a potable water supply source. These
exposure scenarios correspond to potential future use of the Site
for residential development.
Under the current land use scenario, potential human receptors at
the Site include residents in the vicinity of the Site who may be
occasional Site trespassers, and workers on the Site. The Site is
surrounded by residential, agricultural and light industrial areas.
Beyond these areas immediately surrounding the Site (including the
City of Fairfax) , the local area is not densely populated, and
consists primarily of agricultural land and forests. The most
likely potential human receptors under the current land use
scenario are workers and occasional trespassers. No private
drinking water wells were identified either on-Site or immediately
downgradient from the Site, and no users of surface water for
potable water supplies were identified downgradient from the Site.
Under current land use, the Reasonable Maximum Exposure (RME) is
represented by the individual worker or Site trespasser who may be
exposed by direct contact and incidental ingestion of surface soil
and stream sediments.
Potential environmental receptors under the current land use
scenario include the plants and animals at -the Site. Site
features, including the small unnamed stream and wetlands adjacent
to the Site, and nearby wooded areas and open fields, provide a
variety of habitats. No unique or critical habitats have been
identified at the Site, and no vegetative stress is evident based
upon site visits by regulatory personnel. No threatened or
endangered species have been observed at the Site or in adjacent
areas.
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ii
Future land use for the Site was considered to include potential
development of the area as residential property. This potential
land use scenario is considered to be that which would result in
the greatest degree of risk to human health should the Site remain
unremediated. The RME under a residential land use scenario is
assumed to be an adult person or child living on the Site property
and drinking potable water obtained from a private'well drilled
into the Barnwell Formation. Under the future land use scenario,
environmental receptors would likely be more limited than at
present, since residential development of the property would in all
likelihood involve the elimination of the wetland and forested
areas on and adjacent to the Site.
EPA has determined that the elevated levels of pesticides in the
soils and ground waters at the Site pose the primary hazard to
human health at the Site. In addition, the elevated levels of
pesticides in the sediments and soils located in the wetland areas
adjacent to and downstream of the Site pose a hazard to
environmental receptors inhabiting those areas. Primary exposure
pathways for humans are incidental dermal contact with and
ingestion of contaminated soils, and ingestion of contaminated
ground water.
EPA has established in the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP), 40 CFR Part 300, a range of 1 X
10'4 to 1 X 10"6 as acceptable limits for excess lifetime
carcinogenic risks. Excess risk within EPA's acceptable limits
means that any individuals exposed to Site conditions under the
assumed exposure scenarios will run a one in ten thousand (1 X 10~4)
to a one in one million (1 X 10"6) increased chance of developing
cancer. Under the "No Action" scenario, (assuming the Helena
Chemical Site is left as it is now) the estimated carcinogenic risk
for current land use is 8.0 X 10"5. The estimated excess cancer
risk calculated for the future land use scenarios at the Site is
2.6 X 10~4. These calculated risks for the future land use scenario
exceed the acceptable risk levels established by EPA and are based
on the assumption that no cleanup activities will have occurred.
EPA has also established acceptable exposure limits based upon non-
carcinogenic health effects. A Hazard Index (HI) of 1.0 or greater
has been established by EPA as the criterion defining unacceptable
levels of exposure for non-carcinogenic health effects. The HI is
the ratio of exposure levels resulting from site conditions to
acceptable exposure levels (ie., exposure levels that result in no
adverse health affects) for any given contaminant. The HI for
potential non-carcinogenic effects under the current land use
exposure scenario is 0.3. The associated Hazard Index for
non-carcinogenic effects under the future land :use exposure
scenario is 8.6.
Actual or threatened releases of hazardous substances from this
Site, if not addressed by the preferred alternative or one of the
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other active measures considered, may present a current or
potential future threat to the public health, welfare, or the
environment. :
6.1 CONTAMINANTS OF CONCERN
Numerous chemical contaminants were identified in site media during
RI Phases II-A, II-B, and III. The soil contaminants that
contribute the bulk of risks to human health and the environment
are chlorinated pesticides.
In soils, DDT (plus DDE and DDD) , BHC (all isomers), toxaphene and
dieldrin were the most frequently detected and generally were found
in the higher concentrations. Aldrin, endosulfan sulfate, endrin
and endrin ketone were the next most frequently detected
pesticides. Endosulfan, heptachlor, heptachlor epoxide,
methoxychlor, and chlordane were the least frequently detected.
Disulfoton and tributylphosphoro-trithioate (TBPT,
butylphosphorotrithioate) were also detected infrequently, but were
nonetheless evaluated as part of the BRA. Due to the low frequency
of detection and the relatively low concentrations of heptachlor,
heptachlor epoxide and chlordane (both isomers) found in site
soils, these compounds were not evaluated as part of the BRA as it
was determined that they would not contribute significantly to the
overall risk posed by the site. This approach is consistent with
the process for eliminating compounds from further consideration as
outlined in RAGS. Endosulfan sulfate and endrin ketone are not
listed in EPA databases which contain Agency reviewed toxicity
data, and as a result the reference doses (RfD's) of their parent
compounds (endosulfan and endrin, respectively) were used to
compute the risk posed by these compounds. This procedure provided
a conservative estimate of risk (or hazard index).
A large number of inorganic parameters were detected in soil
samples. No inorganic contamination associated with site
activities was found, however, in soils at a frequency and/or
concentration sufficient to warrant consideration as a contaminant
of concern.
7.0 DESCRIPTION OF REMEDIAL ALTERNATIVES
7.1 DESCRIPTION OF ALTERNATIVES CONSIDERED FOR SOIL REMEDIATION IN
SEPTEMBER, 1993. ROD
The Feasibility Study (FS) considered a wide variety of general
response actions and technologies for remediating soil and
groundwater. Based on the FS, Baseline Risk Assessment, and
Applicable or Relevant and Appropriate Requirements (ARARs), the
remedial alternatives for contaminated soils described below were
evaluated.
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Soils on the Site, both at the ground surface and at depths grater
than one foot, are contaminated at levels which exceed criteria
protective of human health under an exposure scenario which assumes
unrestricted land use, including residential development, and which
exceed concentrations that are likely to continue to leach
contaminants to ground water. The overall remedial action
objective for the surface and subsurface soils is to remove and
remediate contaminated soils to such a degree that both ground-
water quality (in conjunction with ground-water extraction and
treatment) and human health are protected. The RI identified soil
remediation goals for both of these purposes. EPA review of the
remedial goals developed in the RI for the protection of ground
water revealed, however, that the technical basis for these goals
was inadequate. EPA therefore conducted an independent analysis of
soil contamination levels and has determined that a soil
remediation goal of 50 ppm total pesticides is protective of human
health and the environment, and will result in the removal of 90%
of the total pesticide mass that exists at the site.
The performance standards for treatment of the soils would satisfy
the Land Disposal Restrictions (LDRs) found in 40 CFR Part 268,
promulgated under the authority of the Resource Conservation and
Recovery Act (RCRA). This proposal is based partly upon the
concept that ground-water quality can be protected by treatment of
soils in these source areas in combination with extraction and
treatment of contaminated ground water. The removal and treatment
of soils in the source areas is also protective of human health via
direct contact and incidental ingestion.
The following descriptions of remedial alternatives are summaries
of more complete descriptions found in the FS report. The FS
report contains a more detailed evaluation of each alternative and
is available for review in the Administrative Record for the Site.
All costs are based upon capital costs plus the present worth of
annual operation and maintenance costs.
7.1.1 Alternative 1 - No Action
By statute, EPA is required to evaluate a "No Action" alternative
to serve as a basis against which other alternatives can be
compared. Under the No Action Alternative, no remedial response
would be performed on contaminated soils at the Site. This
alternative does not reduce the risk calculated by the Baseline
Risk Assessment. The No Action Alternative results in an excess
cancer risk of 8.0 X 10"5 and a Hazard Index for non-carcinogenic
effects of 0.3 for current land use exposure scenarios, and an
excess cancer risk of 2.6 X 10'4 and a Hazard Index for non-
carcinogenic effects of 8.6 for potential future land use
scenarios.
The estimated present worth cost for the no-action alternative is
$480,000. This cost is for monitoring of ground water and soils
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for thirty years.
7.1.2 Alternative 2 - Consolidate Contaminated Soils and Debris in
Onsite Landfill
All alternatives, excluding No Action, include ground-water
containment by means of extraction/ treatment and appropriate
disposal. All alternatives/ with the exception of No-Action, also
include the demolition of on-site buildings as necessary to remove
contaminated soil for treatment. Testing of the demolished
buildings will be conducted during remedial design in order to
determine the appropriate methods of disposal for demolition
debris. It is likely that the demolition debris will not be
significantly contaminated, so that no special handling will be
required, allowing disposal of the demolition debris as non-
hazardous solid waste.
All alternatives, with the exception of the No-Action Alternative,
also include mitigation for contaminated soils and sediments in the
wetland areas adjacent to the Site and downstream.
Alternative 2 calls for the demolition of the former formulation
buildings on the Site, excavation of contaminated soils and
disposal of contaminated soil in an on-site landfill constructed
especially for this purpose. All soils exceeding 50 ppm total
pesticides would be placed in the landfill. The landfill would be
constructed to meet all applicable technical requirements regarding
design of such landfills, including top and bottom liners to
prevent infiltration of rainfall and also to prevent any further
contamination of ground water. Long-term maintenance of the
landfill would be required as part of the implementation of this
alternative.
The estimated cost for this alternative is $5.5 million.
7.1.3 Alternative 3 - Excavation and On-Site Biological Treatment
of Contaminated Soils
The ground water and wetlands portions of this alternative are
identical to those described under Alternative 2. They will
consist of ground-water extraction, treatment and disposal
(preferably in the local sanitary sewer), and mitigation of
wetlands impacts. Demolition of Site buildings will also be as
described under Alternative 2.
Under this alternative, contaminated soils containing greater than
50 ppm total pesticides would be treated on-site by means of
biological degradation. Biological degradation would take place in
treatment cells constructed on-site that would be lined to prevent
any leaching of contaminants to ground waters underlying the Site.
Biological treatment cells would consist of lined pits into which
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the contaminated soils would be placed. Once placed into the
cells, moisture content, temperature and nutrient levels would be
adjusted and maintained to maximize the rate of biological
activity. Both aerobic and anaerobic conditions are envisioned in
order to maximize the effect of biological degradation.
Anticipated treatment would consist of anaerobic treatment,
particularly for soils contaminated with DDT, followed by aerobic
treatment. Some of the Site soils may require aerobic treatment
alone.
Treatability studies would be conducted to determine if this
alternative can achieve the remedial goals, but preliminary data
indicate that significant reductions in concentration of many site-
specific contaminants can be achieved by biological degradation.
Once soils are treated to the remedial goals, they would be
replaced in the on-site excavations from which they were removed.
The performance standard for treatment would be based upon the LDRs
for site-specific contaminants.
The estimated cost for this alternative is $8.0 million
7.1.4 Alternative 4 -Hydrolvtic/Photolytic Dechlorination of
Contaminated Soils
The ground water and wetlands portions of this alternative are
identical to those described under Alternative 2. They will
consist of ground-water extraction, treatment and disposal
(preferably in the local sanitary sewer), and mitigation of
wetlands impacts. Demolition of Site buildings will al-so be as
described under Alternative 2.
Under this alternative, contaminated soils containing greater than
50 ppm total pesticides from the Site would be treated by means of
hydrolytic/photolytic dechlorination (HPD) of the pesticide
contaminants. This process would be implemented at Helena Chemical
by mixing contaminated soils with chemical reagents and exposing
them to heat and ultraviolet (UV) radiation. The mixing process is
necessary to distribute the reagents (usually hydrated lime,
possibly supplemented by sodium hydroxide) throughout the mass of
contaminated material. The mixed material/reagent mass is then
placed in thin layers in cells similar to those proposed for
biological treatment in order for the soils to be exposed to heat
and UV energy from the sun. The soil mass would also be kept moist
in order to enhance biodegradation of any organic end products
resulting from the hydrolytic/photolytic dechlorination process.
Soils would be periodically "turned over" to maximize contaminant
exposure to UV radiation. The performance standard for the
treatment process would be the LDRs for site-specific contaminants.
Treatability studies would also be required to determine if this
technology would be capable of achieving the required performance
standards.
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The estimated cost for this alternative is $7.2 million.
7.1.5 Alternative 5 - Hydrolytic/Photolytic Dechlorination and
Biological Treatment of Soils On-Site
This was the preferred alternative for remediation of the Helena
Site.
The ground water and wetlands portions of this alternative are
identical to those described under Alternative 2. They will
consist of ground-water extraction, treatment and disposal
(preferably in the local sanitary sewer), and mitigation of
wetlands impacts. Demolition of Site buildings will also be as
described under Alternative 2.
Under this alternative, the two technologies discussed under
Alternatives 3 and 4 above would be combined in order to take
advantage of the particular benefits of each. Past studies and
experience with biological treatment have indicated that biological
treatment alone is effective for many of the site-related soil
contaminants at Helena (notably DDT and its metabolites).
Biological treatment alone, however, is less effective for
toxaphene, which is another Site, contaminant found in significant
concentrations, likewise contributing significantly to the risk
associated with Site exposure. HPD, on the other hand, has been
shown in pilot-scale studies to be effective in the destruction of
toxaphene. The two technologies would be combined in a treatment-
train mode, with HPD treatment followed by biological treatment.
In addition to biological treatment of site-specific contaminants
other than toxaphene, the second step of the treatment train would
also serve to further degrade the breakdown products produced by
the initial HPD step.
Otherwise, the treatment processes would be as described under
Alternatives 3 and 4, above. The soil remediation goal would
remain at 50 ppm total pesticides, and the treatment performance
standard would be based upon the LDRs for site-specific
contaminants. The estimated cost for this alternative is $3.9
million.
7.1.6 Alternative 6 - Low Temperature Thermal Desorption of Soils
On-Site
The ground water and wetlands portions of this alternative are
identical to those described under Alternative 2. They will
consist of ground-water extraction, treatment and disposal
(preferably in the local sanitary sewer), and mitigation of
wetlands impacts. Demolition of Site buildings will also be as
described under Alternative 2.
Under this alternative, contaminated soils exceeding 50 ppm total
pesticides from the Site would be treated on-site by means of low
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temperature thermal desorption (LTTD). This process involves
processing contaminated soils through a rotary dryer or kiln. The
soil mass is heated to a temperature level that is sufficient to
drive the contaminants off of the soil matrix, but not high enough
to actually incinerate or destroy the contaminants. Soil
contaminants are volatilized from the solids and purged from the
kiln or dryer by means of an inert purge gas. After the purge gas
leaves the desorption unit, it is treated by an off-gas treatment
system that prevents the soil contaminants from being released into
the environment. Typical air pollution control equipment (such as
cyclonic precipitators and baghouses) are also used to protect air
quality during operation of desorption units.
LTTD typically concentrates the Site contaminants into a low-
volume, highly concentrated waste stream that must in turn be
disposed of in a manner that complies with all environmental
regulations. This residual waste stream would be disposed of
either by incineration or by transport to an approved waste
disposal facility.
Numerous vendors for this type of treatment system exist, and EPA
has experienced good success with its use on soils contaminated
with pesticides at other Superfund sites. Treatability studies
would likewise be necessary in order to assess the suitability of
this technology for application at the Helena Chemical Site. The
performance standard for this treatment system would likewise be
the LDRs for site specific contaminants.
The estimated cost for this alternative is $4.4 million.
7.2 DESCRIPTION OF ALTERNATIVE CURRENTLY UNDER CONSIDERATION FOR
SOIL REMEDIATION
The ground water and wetlands portions of this alternative are
identical to those described under Alternative 2. They will
consist of ground-water extraction, treatment and disposal
(preferably in the local sanitary sewer), and mitigation of
wetlands impacts. Demolition of Site buildings will also be as
described under Alternative 2.
Under this alternative, soils which contain total halogenated
pesticide levels greater than 50 mg/kg in the top three feet of the
soil column would be excavated, transported by truck to the Laidlaw
Environmental Services facility located in Pinewood, South
Carolina, loaded onto railroad cars at the Pinewood facility, and
transported by rail to a hazardous waste incinerator located in
Clive, Utah. The contaminated soils and other wastes will there be
incinerated. This incinerator is also operated by Laidlaw
Environmental Services (LES) and is certified under EPA's Off-Site
Policy by the State of Utah to accept wastes derived from remedial
actions at Superfund sites. The certifying agency is the Utah
Division of Solid and Hazardous Waste, which has been delegated
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authority to implement RCRA regulations by EPA Region VIII. This
certification indicates that the incinerator is operating in
compliance with applicable RCRA regulations governing such
facilities.
Incineration is a thermal treatment technology whereby the
contaminated soils are heated to a temperature at which the
contaminants of concern would be destroyed by oxidation. The end
products of this thermal destruction of organic contaminants are
carbon dioxide and water. Wastes are fed into a combustion chamber
and subjected to elevated temperatures which insure the thermal
destruction of organic contaminants. The end product is a residue
or ash that can be disposed of by placement in a properly designed
landfill. At the LES incinerator facility, the residue would be
disposed of in landfills located on-site at the facility in Clive,
Utah.
8.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
This analysis will compare the alternatives previously selected in
the September, 1993, ROD to the newly identified alternative
described above. The evaluation criteria are the nine criteria
contained in the National Contingency Plan, as discussed below.
For a more detailed description of the remedy selected in the 1993
ROD, please refer to that document.
The alternatives for Site remediation were evaluated based on the
nine criteria set forth in the NCP (40 CFR § 300.430(e) (9) ) . In
the sections which follow, brief summaries of how the alternatives
were judged against these criteria are presented.
8.1 CRITERIA FOR COMPARATIVE ANALYSIS
8.1.1 Threshold Criteria
Two threshold criteria must be achieved by a remedial alternative
before it can be selected.
1. Overall protection of human health and the environment
addresses whether the alternative will adequately protect human
health and the environment from the risks posed by the Site.
Included in judgement by this criterion is an assessment of how and
whether the risks will be properly eliminated, reduced, or
controlled through treatment, engineering controls, and/or
institutional controls.
2. Compliance with applicable or relevant and appropriate
requirements (ARARs) addresses whether an alternative will meet all
of the requirements of Federal and State environmental laws and
regulations, as well as other laws, and/or justifies a waiver from
an ARAR. The specific ARARs which will govern the selected remedy
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are listed and described in Section 9.0, Selected Remedy.
8.1.2 Primary Balancing Criteria
Five criteria were used to weigh the strengths and weaknesses among
alternatives, and to develop the decision to select one of the
alternatives. Assuming satisfaction of the threshold criteria,
these are the main considerations in selecting an alternative as
the remedy.
1. Long term effectiveness and permanence refers to the ability of
the alternative to maintain reliable protection of human health and
the environment over time, once the remediation goals have been
met.
2. Reduction of toxicity, mobility, or volume addresses the
anticipated performance of the treatment technologies that an
alternative may employ. The 1986 amendment to CERCLA, the
Superfund Amendments and Reauthorization Act (SARA), directs that,
when possible, EPA should choose a treatment process that
permanently reduces the level of toxicity of site contaminants,
eliminates or reduces their migration away from the site, and/or
reduces their volume on a site.
3. Short-term effectiveness refers to the length of time needed to
achieve protection, and the potential for adverse effects to human
health or the environment posed by implementation of the remedy,
until the remediation goals are achieved.
4. Implementability considers the technical and administrative
feasibility of an alternative, including the availability of
materials and services necessary for implementation.\
5. Cost includes both the capital (investment) costs to implement
an alternative, plus the long-term O&M expenditures applied over a
projected period of operation.
8.1.3 Modifying Criteria
State acceptance and community acceptance are two additional
criteria that are considered in selecting a remedy, once public
comment' has been received on the Proposed Plan.
1. State acceptance; The State of South Carolina concurs with
this remedy.
2. Community acceptance was indicated by the verbal comments
received at the Helena Chemical NPL Site Proposed Plan public
meeting, held on May 27, 1993. The public comment period opened on
May 18, 1993, and closed on June 17, 1993.
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8.2 COMPARISON OF ALTERNATIVES
Both alternatives (i.e., on-Site treatment by HPD/LTTD, and off-
Site treatment by incineration) provide adequate protection of
human health and the environment. Both alternatives achieve all
identified ARARs, including both those identified in the September,
1993, ROD and additional ARARs identified below. With respect to
the balancing criteria of long-term effectiveness, reduction of
toxicity, mobility, or volume, and implementability, both
alternatives are comparable. Both adequately satisfy these
balancing criteria to a similar degree.
With respect to short-term effectiveness, the incineration
alternative is preferable in that the remedial action can be
implemented much more quickly than would be the case by using
HPD/LTTD. Using HPD/LTTD, a lengthy design and evaluation process,
followed by a procurement and construction phase, would be
necessary before remedial action could begin. The availability of
disposal capacity at the LES incinerator in Utah is such that the
remedial action could begin in a much shorter time frame,
accelerating the remedial action for contaminated soils at this
Site.
With respect to cost, the incineration alternative is preferable in
that it is much less costly. Preliminary estimates by Helena
Chemical Company indicate that the incineration alternative will be
as much as $2 million less costly than the on-Site remedies
contained in the original ROD. The cost savings are realized in
part because of the need for LES to obtain sufficient material to
conduct a sustained trial burn at the Utah incineration facility.
In order to obtain sufficient material to conduct this trial, LES
is providing the incineration service at a reduced cost to parties,
such as Helena Chemical Company, who have readily available waste
of a suitable nature.
9.0 SELECTED REMEDY
Based upon consideration of the requirements of CERCLA, the NCP,
the detailed analysis of alternatives and public and state
comments, EPA has determined that the use of off-Site incineration
is the most appropriate remedial action for contaminated soils and
waste materials at the Helena Chemical Superfund site. The total
present worth cost of the selected remedy, as amended by this ROD
amendment, will be approximately $2 million.
9 . 1 DESCRIPTION OF SELECTED REMEDY AS AMENDED
Source control will address the contaminated soils and waste
materials at the Site. Source control shall include excavation of
contaminated soils and waste materials, transport to an off-Site
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incineration facility located in Clive, Utah, off-Site treatment by
means of incineration, and placement of the treated soils and waste
materials into land disposal units at the incineration facility in
Clive, Utah.
The major components of source control to be implemented include:
1. Excavation of materials contaminated with greater than 50 ppm
of total pesticides at the Site. Excavation will be limited
to the uppermost three feet of soils at the Site in order to
prevent creation of a preferential flow path for infiltration
of rain water into the shallow aquifer.
2. Treatment of all excavated materials by means of incineration
at the LES incinerator located in Clive, Utah. Transport to
the LES incinerator will be by truck from the Site, located in
Fairfax, SC, to the LES facility located in Pinewood, SC. The
contaminated soils and waste materials will then be
transported by rail from Pinewood, SC, to the incinerator
facility.
An additional element of the source control portion of the overall
remedy will be to grade the Site and construct any structures or
appurtenances necessary so that the Site complies with all
regulations regarding storm water run off from industrial
facilities. This will prevent any further non-point source
contribution from future Site activities to contamination in
adjacent waters of the United States.
All other components of the remedial action for the Site (i.e.,
those related to ground-water remediation and wetlands mitigation)
as described in the September, 1993, ROD will remain in full force
and effect.
Compliance testing of the residual soils that have been subjected
to treatment will also be performed, to insure compliance with the
LDR requirements established as performance standards for the soil
treatment technology.
9.2. APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS (ARARs)
The remedy as amended will comply with all applicable portions of
the following Federal and State regulations, in addition to those
specified in the September, 1993, ROD:
40 CFR Part 262, Subparts A, B, C and D, promulgated under the
authority of the Resource Conservation and Recovery Act.
40 CFR Part 263, Subparts A, B, and C, promulgated under the
authority of the Resource Conservation and Recovery Act.
40 CFR Part 264, Subpart 0, promulgated under the authority of the
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Resource Conservation and Recovery Act.
10.0 STATUTORY DETERMINATIONS
The selected remedy for this Site meets the statutory requirements
set forth at Section 121(b)(l) of CERCLA, 42 U.S.C. § 9621(b)(l).
This section states that the remedy must protect human health and
the environment; meet ARARs (unless waived); be cost-effective; use
permanent solutions, and alternative treatment technologies or
resource recovery technologies to the maximum extent practicable;
and finally, wherever feasible, employ treatment to reduce the
toxicity, mobility or volume of the contaminants. The following
sections discuss how the remedy fulfills these requirements.
Protection of human health and the environment; The selected soil
remedy will remove the human health risks from dermal contact and
incidental ingestion of contaminated Site soils.
Compliance with ARARs; The selected remedy will meet ARARs, which
are listed herein and in Section 9.2 of the September, 1993, ROD.
Cost effectiveness; The selected soil remedy component is the most
cost effective of the alternatives considered. . Among the
alternatives that are protective of human health and the
environment and comply with all ARARs, the selected alternative is
the most cost-effective choice because it uses a treatment method
for which costs can be reliably predicted.
Utilization of permanent solutions, and alternative treatment
technologies or resource recovery technologies to the maximum
extent practicable; The selected remedy represents the maximum
extent to which permanent solutions and treatment can practicably
be used for this action. All of the selected remedy components are
considered permanent solutions.
Among the alternatives that are protective of human health and the
environment and comply with all ARARs, EPA and the State of South
Carolina have determined that the selected remedy achieves the best
balance of trade-offs in terms of long-term effectiveness and
permanence, reduction of toxicity/mobility/volume, short-term
effectiveness, implementability, and cost.
Preference for treatment as a principal remedy element; The soil
remedial action will satisfy the preference, due to the treatment
of soils by the selected technology, off-Site incineration.
Likewise, the contingency remedy fully satisfies this preference.
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