PB94-964507
EPA/ROD/R09-94/111
July 1994
EPA Superfund
Record of Decision:
Southern California Edison.
Visalia Pole Yard Site,
Visalia, CA
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RECORD OF DECISION
Southern California Edison, Visalia Pole Yard Superfund site
Visalia, California
EPA ID# CAD980816466
PART I - DECLARATION
statement of Basis and PurDose
This Record of Decision (ROD) presents the selected remedial
action for the Southern California Edison, Visalia Pole Yard,
Superfund Site (the Site) in Visalia, California. This document
was developed in accordance with the Comprehensive Environmental
Response, Compensation and Liability Act of 1980, (CERCLA), as
amended by the Superfund Amendments and Reauthorization Act of
1986 (SARA), 42 U.S.C. SS9601 et seq., and, to the extent
practicable, in accordance with the National oil and Hazardous
Substances Pollution Contingency Plan (NCP), 40 C.F.R. Part 300,
and the laws of the State of California. This decision is based
on the Administrative Record for the Site. The administrative
record index identifies the documents upon which the selection of
the remedial action is based.
The State of California Department of Toxic Substances
Control (DTSC) is the lead agency which has been responsible for
overseeing the Remedial Investigation and Feasibility Study
(RIfFS) for this site. The State has finalized its selection of
a remedial action for the site in its Remedial Action Plan (RAP).
with this Record of Decision, EPA selects and concurs with the
remedy chosen in the state's RAP.
Assessment of the site
Actual or threatened releases of hazardous substanc~s from
this Site, if not addressed by implementing the response action
selected in this ROD, may present an imminent and substantial
endangerment to public health, welfare, or the environment.
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Description of the Remedv
The Southern California Edison (SCE), Visalia Pole Yard(VPY)
site is located at 432 North Ben Maddox Way in northeastern
Visalia, Tulare County, California. The facility was used for
utility pole treatment operations from 1925 until 1980. Between
1925 and 1968, creosote was used as a wood preservative and was
delivered to the site in railroad tank cars. A series of
four inch underground product lines transferred the creosote from
the rail cars to the 100,000 gallon above ground cold storage
tank. When poles needed to be treated, the creosote was heated
by steam lines underlying the tank. The heated creosote was then
pumped to the treatment tanks. After treatment was completed,
the hot creosote was pumped to one of two 16,000-gallon above-
ground insulated hot storage tanks. In 1968, the treating fluid
was changed from creosote to a 5 percent by weight solution of
pentachlorophenol dissolved in a diesel oil carrier fluid.
Diesel fuel was stored in underground storage tanks located west
of the VPY office, operations continued until June 1980 when the
VPY site was closed.
During 1980 and 1981, SCE contracted to demolish the former
pole treating facilities. Once destroyed, these structures were
disposed of at the class I facility in Kettleman Hills,
California. The sources of chemical release of creosote and
pentachlorophenol (PCP) were primarily in the piping between the
storage tanks and the treatment tanks, and failures in the
treatment tanks. Groundwater remediation activities have been in
operation at the site since 1975.
Regulatory actions related to the VPY began in 1976, when
the California Regional Water Quality Control Board, Central
Valley Region (RWQCB) issued a Cleanup and Abatement Order
requiring SCE to: 1) "discontinue discharge of chemicals related
to pole treatment operations"; 2) "extract and treat contaminated
groundwater"; and 3) "contain contamination on site". SCE
complied with these provisions by installing groundwater
extraction wells and constructing a slurry wall keyed into the
shallow aquitard beneath the VPY site. In September 1986, the
RWQCB adopted Water Discharge Requirements (WDRs) and approved a
National Pollutant Discharge Elimination System (NPDES) permit
for discharge from a pretreatment plant which was installed.
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The interim response actions addressed the principal threats
at the Site. The final remedy addresses threats remaining after
the interim measures. Estimated potential risks under current
conditions include both occupational and off-site residential
exposure scenarios. The major components of the selected remedy
include:
in-situ bioremediation
property access restrictions
deed restrictions
and may include if necessary:
soil capping
statutory Determinations
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that
are legally applicable or relevant and appropriate ("ARARs") to
the remedial action, and is cost effective. The selected remedy
uses engineering controls to address remaining low levels of
hazardous substances at the site. Concentrated wastes which may
have presented principal threats at the site were addressed by
interim remedial measures prior to the enactment of SARA and the
CERCLA S121 preference for treatment. Because this remedy will
result in hazardous substances remaining on-site, a review will
be conducted within five years after the commencement of remedial
action, and every five years thereafter, to ensure that the
remedy continues to provide adequate protection of human health
and the environment.
#lN~
John wi
Deputy Regional Administrator
G..fO.QI
Date
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PART II - DECISION SUMMARY
Southern California Edison, Visalia Pole Yard Superfund site
Visalia, California
A detailed analysis of the selected remedial action for the
Southern California Edison (SCE), Visalia Pole Yard (VPY),
Superfund site is contained in the Remedial Action Plan (RAP),
prepared by DTSC in October, 1993. The site information
summarized below is discussed fully in the RAP. After
considering public comments, the State adopted the draft RAP,
with minor changes, as the final RAP. EPA's Record of Decision
concurs with the State's action, and selects the remedial action
alternative proposed in the draft RAP without change.
1. Site Name. Location. and Description.
The Southern California Edison, Visalia Pole Yard, Superfund
site is located at 432 North Ben Maddox Way in northeastern
visalia, Tulare County, California. The site is bounded on the
North by East Goshen Avenue and on the West by North Ben Maddox
Way. .Visalia is approximately midway between Fresno and
Bakersfield in the Central Valley of California, and is a growing
metropolitan area with a population of approximately 75,000.
Agriculture is the dominant industry in the region and walnuts,
olives, and citrus are the primary crops.
The VPY site is divided into three distinct areas: 1) The
southwest corner of the site was the main pole treatment
operation area and is referred to as the Pole Treatment Area (PT
Area); 2) The eastern portion of the site where newly arriving
poles were stored for seasoning. This area is referred to as the
Pole Storage Area (PS Area)iand 3) The northwestern corner of
the site acted as a hub for electric transmissions, work
distribution area, and automotive maintenance garage. This area
is known as the Visalia Service Center (VSC Area). The western
half of the property known as the VSC Area and the PT Area
currently contains offices, a warehouse, other buildings, and the
groundwater treatment plant. The former pole treating equipment
and structures have been removed from PT Area.
The PS Area consists mostly of open land where mostly
untreated poles were stored. In the southern portion of the PS
Area some remnants remain of the buffing and incising facility
and tracks used in the processing of poles prior to treatment.
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2. site Historv and Enforcement Activities.
The facility was used for pole treatment operations from
1925 until 1980. The PT Area and the PS Area combined, comprise
the Visalia Pole Yard Wood Treatment operation. The PT Area was
the main pole treatment operation area and is the main focal
point for remediation of the site. The PS Area was where
untreated poles were stored for seasoning. The VSC Area acted as
a hub for electric transmissions, the work distribution area, and
the automotive maintenance garage.
Fresh, debarked, western red cedar was shipped via rail to
the PS Area of the site for seasoning and milling into utility
poles. Dried wooden poles were shaved and cut to appropriate
lengths and then moved to the PT Area for treatment. The PT Area
consisted of two butt dip tanks and one full dip tank and
supporting tanks and equipment used in the treatment operation.
Between 1925 and 1968, creosote was used as a wood
preservative and was delivered to the site in railroad tank cars.
A sertes of four inch underground product lines transferred the
creosote from the rail cars to the 100,000 gallon above ground
cold storage tank. When poles needed to be treated, the creosote
was heated by steam lines underlying the tank. The heated
creosote was then pumped to the treatment tanks. After treatment
was completed, the hot creosote was pumped to one of two 16,000-
gallon above-ground insulated hot storage tanks.
In 1968, the treating fluid was changed from creosote to a
5 percent by weight solution of pentachlorophenol dissolved in a
diesel oil carrier fluid. Diesel fuel was stored in underground
storage tanks located west of the VPY office. Operations
continued until June 1980 when the VPY site was closed.
During 1980 and 1981,
pole treating facilities.
disposed of at the Class I
California.
SCE contracted to demolish the former
Once destroyed, these structures were
facility in Kettleman Hills,
Regulatory actions related to the VPY began in 1976, when
the California Regional Water Quality Control Board, Central
Valley Region (RWQCB) issued a Cleanup and Abatement Order
requiring SCE to: 1) "discontinue discharge of chemicals related
to pole treatment operations"j 2) "extract and treat contaminated
groundwater"j and 3) "contain contamination on site". SCE
complied with these provisions by installing groundwater
extraction wells and constructing a slurry wall keyed into the
shallow aquitard beneath the VPY site.
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The RWQCB approved a National pollutant Discharge
Elimination System (NPDES) permit for discharge from the
pretreatment plant. This Order became effective in September
1986.
The VPY site was listed on the state Superfund list in June
1985. As a result of this listing, SCE and DTSC signed an
Enforceable Agreement, effective December 1987. The Enforceable
Agreement was signed to ensure that past releases of hazardous
substances to the air, soil, surface water, and groundwater are
investigated and appropriate remedial action(s) are taken, to
satisfy local, state, and federal requirements.
The VPY site was ad4ed to the National Priorities List (NPL)
on March 31, 1989. DTSC is the lead agency at this site for both
u. S. EPA and State activities associated with CERCLA.
3. Hiqhliqhts of Community Participation.
In October, 1993, DTSC released a proposed plan and RIfFS
for the site. Site documents were made available at the lead
agency offices and a local repository, the public library in
Visalia. A public notice was published allowing 30 days for
public comment on the RIfFS and draft RAP, which served as the
equivalent of a proposed plan, consistent with the requirements
of the NCP. A public meeting was held on October 19, 1993 to
describe the proposed remedy and receive comments. No members of
the public were present at the public meeting. The decision for
this site is based upon the Administrative Record.
4. Scope and Role of Remedial Actions
The remedial actions selected in this Record of Decision
will be the final response actions performed at the site. As
described in the Site history above, significant interim remedial
measures were performed at the site in the past. These actions
addressed many of the threats at the Site. The selected remedy
addresses the contaminants remaining in soils and groundwater at
the Site.
5. Site Characteristics.
site investigations have included sampling and analysis of
surface and subsurface soils, groundwater, and surface water.
Three aquifers designated as the shallow, intermediate, and
deeper aquifers, have been delineated in the upper 180 feet of
the unconsolidated sediment beneath the VPY site. The
approximate intervals below ground surface where the units occur
are listed below.
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Hvdrostratiqraphic unit
Approximate Depth lft)
Shallow Aquifer (presently dry)
Intermediate Aquifer(partial saturated)
Deeper Aquifer
30
75
120
52
100
180 +
The three aquifers are separated by aquitards: the shallow
aquitard and the intermediate aquitard. The known points of
release of creosote and pentachlorophenol (PCP) in the PT Area
were primarily in the piping between the storage tanks and the
treatment tanks, and through cracks or failures in the treatment
tanks. At the PS Area, the primary potential source of
constituents in the surface soils were the pole treating
chemicals dripping from poles that were occasionally stored in
this area or from pole-handling equipment.
The key chemicals in the soil and groundwater beneath the
vpy site are:
.
.
.
.
.
.
.
chrysene;
2-methylnaphthalene;
naphthalene;
phenanthrene;
diesel;
OCDD; and
PCP.
Pole treating chemicals are found in the groundwater as both
a dissolved phase and free product phase. The dissolved phase
concentrations are generally low because of the low solubility
these chemicals have in water, coupled with the long-term
remedial pumping SCE has conducted. Free phase contaminants are
also described as Non Aqueous Phase Liquids (NAPLs).
Light NAPLs (LNAPLs) at the VPY site consist of diesel oil
used with PCP before use in the wood-treatment process. The
diesel NAPL has moved downward as the water table declined due to
drought conditions. Spilled pole treating chemicals (dissolved,
LNAPLs, and dense NAPLs or DNAPLs) entered the soil and ~igrated
vertically through the vadose zone. At approximately 30 ft
depth, the chemical front reached the silt layer where lateral
spreading occurred. LNAPLs and DNAPLs rested on top of the 30 ft
silt layer until enough head pressure was developed to facilitate
migration through the 30 ft silt. The chemical front reached the
shallow aquifer at the historical water table of approximately 35
ft below land surface. LNAPLs floated on top of the historical
water table and spread southwesterly. Dissolved contamination in
the shallow aquifer spread laterally by advection and dispersion
following groundwater flow.
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contamination migrated downward to the shallow aquitard, a
silty layer at approximately 50 ft depth, and spread out
laterally above the shallow aquitard.
The dissolved-phase and DNAPL contamination has moved into
the intermediate aquifer. This vertical DNAPL migration has been
retarded from reaching the deep aquifer by the intermediate
aquitard. DNAPLs have reached the upper boundary of the
intermediate aquitard and have spread laterally at an approximate
depth of 100 ft.
Groundwater remediation activities have been in operation at
the site since 1975. Only four pole treating chemicals were
detected in groundwater in the deeper aquifer during the January
1991 sampling round. Subsequent ongoing monitoring has not
detected the presence of the chemicals in the deeper aquifer.
6. Summarv of site Risks.
A baseline Public Health Evaluation (PHE) was performed in
order to evaluate the potential impacts from the site, to provide
the basis for selecting remedial action alternatives, and to
develop environmental media-specific clean-up goals. The most
recent validated data set (1991) from soil and groundwater was
used to establish baseline conditions for the site. Based on
current u. S. EPA guidance, it was hypothetically assumed that
current remediation activities would stop and the site would be
uncontrolled. This assumption does not correspond either to the
current conditions at the site, or to the current or future plans
for the VPY site by SCE. The evaluation of health risks
corresponding to these baseline conditions are hypothetical and
do not necessarily represent actual or absolute estimates of
health risks, but are estimates of relative risk. These
assumptions are used for risk comparisons in the risk management
process.
Estimated potential risks under current conditions include
both occupational and off-site residential exposure scenarios.
The on-site occupational exposures are evaluated based on 250
days per year for worker and 350 days per year for off-site
residents. The occupational scenario includes both dust
inhalation, with an excess lifetime cancer risk of 1. 2 X 10-13 and
a Hazard Index of 8.6 x 10-11, and dermal soil contact, with an
excess lifetime cancer risk of 1.6 x 10-8 and a Hazard Index of
3.3 X 10-4.
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Risks for future exposure scenarios associated with
hypothetical ingestion of groundwater from the intermediate
aquifer exceeded the target total potential carcinogenic risk for
several potentially exposed populations. The risks were
calculated based on the intermediate aquifer groundwater
exposures on-site, at the VPY fence line, and for potential
groundwater exposures at the water supply well designated CWS-7.
The following total site reasonable maximum exposures, (RMEs)
exceeq,ed 1 x 10-4:
.
.
.
.
On-site occupational
Off-site occupational (fence line well)
Off-site occupational (CWS-7 well)
Off-site residential adult (fence line well)
Off-site residential adult (CWS-7 well)
Off-site residential children
(fence line well)
Off-site residential children (CWS-7 well)
2 . 6 X 10-3
7.4 X 10-2.
5.4 X 10-4
2 . 4 X 10-1
1.8 X 10-3
.
.
.
1.2 X 10-1
8.4 X 10-4
The primary contribution to risk for each of these
populations is the estimated hypothetical future ingestion of
groundwater from the intermediate aquifer. On-site wells are
used for groundwater monitoring and treatment extraction purposes
only. Thus, groundwater exposures evaluated in this risk
assessment are hypothetical. Fence line exposures are likewise
hypothetical.
7. DescriDtion of Alternatives.
The remedial action objectives for soil at the VPY site
are:
.
Prevent the migration of pole treating chemicals, present
in unsaturated soil, to groundwater.
.
Prevent occupational exposure to soil with constituent
concentrations exceeding health-based concentrations.
The remedial action objectives for groundwater at the VPY
site are presented below.
.
Prevent the residential and occupational exposure to
groundwater with chemical concentrations above the
remediation goals.
.
Prevent the dermal occupational exposure to groundwater
with contaminant concentrations above the remediation
goals.
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Alternative technologies and remedial measures were
identified and screened. Risk-based remediation goals, based on
a 1 x 10-4 through 1 x 10-6 site-wide target risk, have been
developed. Groundwater and soil alternatives remaining after
initial screening of remedial measures are described in detail in
the RAP.
soil
These selected remedial alternatives that passed initial
screening include four for soil and six for groundwater as
follows:
.
soil Remedial Alternative S-l - No Action.
. Soil Remedial Alternative S-2 - Capping and Deed
Restriction.
.
Soil Remedial Alternative S-6 - capping and In-Situ
Bioremediation.
.
,Soil Remedial Alternative S-7 - capping and In-Situ
Stabilization.
Groundwater
.
.
.
.
.
.
Groundwater Remedial Alternative G-1 - No Action.
Groundwater Remedial Alternative G-8 - Monitoring, Slurry
Wall, and In-situ Bioremediation.
Groundwater Remedial Alternative G-10 - Monitoring,
Groundwater Extraction and Physical/Chemical Treatment with
Surface Water (NPDES) Discharge.
Groundwater Remedial Alternative G-14 - Monitoring,
Groundwater Extraction and Physical/Chemical Treatment with
Surface Water Discharge, In-situ Bioremediation for DNAPLs.
Groundwater Remedial Alternative G-15 - Monitoring~
Groundwater Extraction and Physical/Chemical Treatment with
Surface Water Discharge, Enhanced Extraction for DNAPLs.
Groundwater Remedial Alternative G-16 - Monitoring,
Groundwater Extraction and Physical/Chemical Treatment with
recharge, In-Situ Bioremediation.
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8. 8ummarv of Comparative Analvsis of Alternatives.
Each alternative has been analyzed with respect to the
NCP's nine criteria. A detailed analysis is presented in the
RAP.
The no-action Remedial Alternative, 8-1, does not reduce
site risks sufficiently to provide adequate protection of human
health and the environment. Remedial Alternative 8-2 provides
protection of human health but does not protect the environment
when compared to Remedial Alternatives 8-6 and S-7. Remedial
Alternative S-6 provides protection of human health and the
environment. Remedial Alternative 8-7 provides protection of
human health and moderate protection of the environment as long
as the site cap retains integrity.
Remedial Alternative 8-1 is not effective in the short-term
or long-term in satisfying the remedial action objectives. The
remaining alternatives are effective in the short-term in
protecting human health and the environment. There exists the
potential for exposure to workers involved in the excavation of
the hot spots on the PS Area, and during cap construction, well
construction/cap construction and in-situ stabilization during
implementation of Remedial Alternatives S-2, 8-6 and 8-7,
respectively.
Remedial Alternative 8-1 does not include treatment of
contaminants in soil. However, natural attenuation processes
will reduce the toxicity, mobility, and volume of the pole
treating chemicals. with this alternative, reduction rates of
toxicity, mobility, and volume will vary between different
chemicals; however the time required to reach safe levels for all
contaminants would considerably exceed that for the action
alternatives.
The remaining alternatives incorporate a site cap. The cap
provides a reduction in chemical mobility by preventing surface
water infiltration and subsequent downward migration. Remedial
Alternative 8-7 includes in-situ soil stabilization, which
provides for additional chemical immobilization. However, soil
stabilization may not be effective for all of the pole treating
chemicals at the site.
There are no chemical-specific applicable or relevant and
appropriate requirements (ARARs) for the soil remedial
alternatives. The cleanup levels for soil are not based on ARARs
but rather are risk-based. The alternatives incorporating a cap
would comply with California's hazardous waste facility closure
requirements--specifically, Title 22 California Code of
Regulations (lfCCRIf) ~~66264.310(a) and (b) and 66264.117(d).
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Remedial Alternative S-6 is the only alternative that
assures treatment of all organic contaminants. Consequently,
there would be a reduction in toxicity and volume of chemicals
over time. The time requi~ed for remediation in this alternative
would be considerably less than required for natural
bioremediation.
Remedial Alternative S-6 provides long-term effectiveness
as it permanently reduces mobility and volume of the pole
treating chemicals. Alternative S-7 would reduce the mobility of
some, but not all, of these compounds, providing permanence only
for those that are stabilized. In general, only alternative S-6
permanently reduces toxicity, mobility, or volume of the
chemicals. The Alternatives S-2 and S-7 are generally only
effective in the long-term to the extent that the site caps
included in these alternatives are adequately maintained.
The no action Remedial Alternative G-l, does not reduce
site risks sufficiently to provide adequate protection of human
health and the environment. Protection under Remedial
Alternative G-8 is uncertain. The remaining alternatives provide
protection of human health and the environment. The remaining
alter~atives retained for detailed analysis, G-10, G-14, G-15,
and G-16, provide for plume containment with a series of
groundwater recovery wells and ex-situ treatment as the primary
remedial technology. Overall protection would be increased in
those alternatives that decrease the required remedial time frame
(alternatives G-14, G-15, G-16).
The chemical-specific ARARs for the groundwater remedial
alternatives are the maximum contaminant levels (MCL) for
pentachlorophenol (.001 mg/l), benzopyrene (.0002 mg/l) and
dioxin (.00000003 mg/l). The other cleanup levels for groundwater
contaminants of concern, which are set forth in the state's RAP,
are risk-based. Remedial alternatives G-10, G-14, G-15, and G-16
would comply with ARARs.
Remedial Alternative G-10 is the baseline technology for
Remedial Alternatives G-14, G-15, and G-16. Remedial Alternative
G-10 may require several hundred years to achieve remedial
objectives.
Remedial Alternative G-16 may reduce remediation time.
Bioremediation can be phased in while ex-situ groundwater
treatment is in operation.
Remedial Alternatives G-14 and G-15 would also reduce the
required remedial time, relative to Remedial Alternative G-IO, if
the DNAPLs remedial technologies prove effective. Hydrocarbons
will leach from the DNAPL to the saturated alluvium and the
groundwater for an extended period of time. Remedial
Alternatives G-14 and G-15 include provisions for the reduction
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in DNAPLs volume.
9. Selected Remedv.
Remedial alternatives were evaluated based on the nine
criteria established by the NCP.
Remedial Alternative S-6 has been selected to remedy the
impacted soil at the VPY site. This alternative consists of
implementing bioremediation technologies to remedy the soil
contamination, along with asphaltic concrete capping of the soil,
if necessary, until bioremediation goals are met. Institutional
controls will be instituted to reduce access to the Site
throughout the duration of remediation. If necessary, capping
will be used as a .surface barrier for isolating contaminated
soils from direct contact, dust suppression, and infiltration. A
more rigorous RCRA cap may be needed if bioremediation is not
effective. The cap would be constructed over the entire area of
the impacted soil unit. The area to be capped is approximately
20,000 square yards. If an asphaltic concrete cap is installed
the layer thickness would be approximately 3-inches. This is
adequate based on the assumption that minimal car traffic and no
more than an equivalent of one truck per day is expected.
Institutional controls will be instituted to reduce access
to the VPY site and the soil unit throughout the duration of the
site remediation. Institutional controls are needed to insure
protection to public health based on present or future use.
Institutional controls will control the following items:
.
Property access restrictions, such as fencing, posting
and secured site access.
.
Signs warning against unauthorized entry onto the site.
.
Site-use restrictions to prevent unauthorized borings,
earthwork and construction.
.
Deed restrictions to limit site activities to commercial
or industrial uses only. DTSC approval prior to
implementation of any cap destruction or construction
activities.
Remedial Alternative G-16 has been selected to remedy the
groundwater at this site. This alternative is based primarily on
the continued use of the existing physical and chemical treatment
system. In-situ bioremediation is included as an additional.
treatment mechanism. The DNAPL phase is also addressed in this
alternative through the application of the in-situ bioremediation
technology. Recharge to the vadose zone soils will be
incorporated to enhance the soils remediation S-6 above.
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The impacted groundwater plume will continue to be
hydraulically controlled by a series of extraction wells.
Groundwater remediation will be conducted primarily ex-situ, with
enhanced in-situ bioremediation incorporated into the overall
approach. Treated groundwater will be recharged to the alluvial
aquifer on site or recharged to infiltration galleries.
A series of groundwater extraction wells have been
constructed at the VPY site based on available site data and
groundwater modeling. Groundwater treatment removes PCDDs,
PCDFs, and semi-volatile organic compounds. The PCDDs and PCDFs
are generally adsorbed ontq suspended soil particles. These
suspended particles are filtered out of the groundwater. The
filter residue is handled as a hazardous waste and disposed of
off-site. The remaining organic compounds are removed from
groundwater by activated carbon. This carbon is reactivated off
site by the carbon vendor.
Institutional controls will be instituted to reduce access
to the site and groundwater throughout the duration of
groundwater remediation. Institutional controls, in addition, to
the controls described for soil remediation above, will include
the following items:
.
Property access restrictions, such as fencing and
secured site access.
.
Signs warning against unauthorized entry onto the site.
.
site-use restrictions to prevent unauthorized borings
and well construction.
.
Deed restrictions preventing property transfer during
groundwater ~emediation.
.
Deed restriction requiring that future buyers of the
site be made aware of the site's environmental history.
.
Restriction of well installation around the site which
may have adverse effect on groundwater remediation.
Overall protection of human health and the environment:
The selected soil and groundwater remedies provide appropriate
overall protection of human health and the environment. The
bioremediation of the soil will reduce the mass of pole treating
chemicals by aerobic bacterial degradation. Institutional
controls and, if necessary, capping, will provide further
protection. The selected groundwater remedy provides protection
through institutional controls, groundwater monitoring,
groundwater extraction, ex-situ physical and chemical treatment,
on-site recharge of treated groundwater into the alluvium, and
enhanced in-situ bioremediation.
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compliance with ARARs: There are no chemical-specific ARARs with
respect to the soil. However, action-specific ARARs exist with
respect to the cap, if a cap is utilized. The extent of the
capping requirements will be dependent on the degree of success
achieved by the bioremediation. If the bioremediation is
successful, a cap of the kind contemplated by RCRA will not be
necessary. On the other hand, if the bioremediation is not
successful, a more permanent cap may be required, and in that
event certain RCRA requirements would be relevant and
appropriate. The closure and post-closure requirements set forth
in Title 22 California Code of Regulations SS66264.310(a) and (b)
and 66264.117(d) are relevant and appropriate. It should be
noted that where RCRA closure is relevant and appropriate (rather
than applicable), the National Contingency Plan permits a hybrid
closure. Therefore, the RCRA closure requirements could be
applied with 'more flexibility.
The chemical-specific ARARs for the groundwater remedial
alternative are the maximum contaminant levels (MCL) for
pentachlorophenol (.001 mg/l) , benzopyrene (.0002 mg/l) , and
dioxin (.00000003 mg/l). The selected remedial alternative will
comply with those requirements. The other cleanup levels for
contaminants of concern, which are set forth in the RAP, are
risk-based.
with respect to the action-specific ARARs for the
groundwater remedy, the treatment and reinjection of contaminated
groundwater at the site may constitute the operation of a Class
IV well under the Underground Injection Control Program. See 40
C.F.R. Part 144. Under 40 C.F.R. S144.6(d), Class IV wells
include wells used to inject hazardous waste into a formation
which contains, within one quarter mile of the well, an
underground source of drinking water, pursuant to 40 C.F.R.
144.13(c). Such injection is permissible provided that it is
approved by EPA pursuant to provisions for cleanup of releases
under the Comprehensive Environmental Response, Compensation, and
Liability Act of 1980 (CERCLA). Accordingly, the injection
provided for in the selected remedy will meet this ARAR.
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It should be noted that the RCRA land disposal
restrictions, set forth at 22 CCR ~66268.l et seq., are not
ARARs, notwithstanding that creosote (UD51) is a listed waste
pursuant to 22 CCR ~66268.35 and PCP is a "California list waste"
pursuant to 22 CCR ~66268.32.
Under EPA's "contained-in policy", a media such as
groundwater that contains a hazardous waste must be managed as a
hazardous waste as long as the media contains the listed waste.
However, each EPA region has authority to determine when a media
no longer contains a hazardous waste. If the contaminants from
the listed waste are at levels that EPA determines are
acceptable, then EPA will no longer consider the media to contain
hazardous waste, and the land disposal restrictions will not be
triggered. Since the proposed groundwater treatment. alternatives
at the VPY site will treat the groundwater to levels that EPA and
DTSC find acceptable for the contamination, the treated
groundwater will not contain a hazardous waste. Accordingly, the
selected remedial alternative will not trigger the land disposal
restrictions.
Long-term effectiveness and permanence: The selected remedial
alterrtative for soils provides long-term effectiveness as it
permanently reduces mobility and volume of the pole treating
chemicals. A deed restriction prohibiting certain future site
development and uses will provide additional assurance of long-
term effectiveness. The selected groundwater remedy provides
long-term effectiveness as it provides a permanent reduction in
the concentration of the pole-treating chemicals.
Reduction of toxicity, mObility, or volume through treatment:
The selected remedy incorporates treatment of soil contamination
through in-situ bioremediation which will reduce the toxicity,
mobility and volume of pOle-treating chemicals. The selected
groundwater remedy includes ex-situ and in-situ treatment. The
ex-situ treatment will remove chlorinated hydrocarbons from
extracted groundwater by filtration of suspended solids (certain
chlorinated hydrocarbons are adsorbed to the solids). Dissolved
hydrocarbons are removed by granular activated carbon (GAC)~
These activities provide a permanent reduction in contaminant
toxicity and volume. In addition, the in-situ bioremediation
will provide further reduction of the toxicity and volume of the
contaminants.
Short-term effectiveness: The selected soils remedy is effective
in the short-term in protecting human health and the environment.
The reduction of contaminants in the groundwater will require a
substantial period of time. However, the selected remedy, by
utilizing an enhanced in-situ bioremediation process in
conjunction with ex-situ groundwater treatment, may reduce
remediation time in comparison with the other remedial
alternatives.
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Implementability: The selected remedial alternative can be
implemented, although some time will be required because an
effective in-situ bioremediation program requires extensive
testing prior to full-scale application. The selected
groundwater remedy incorporates an existing ex-situ treatment
system that has already been successfully implemented during
interim remedial activities. Thus that portion of the remedy can
be initiated immediately. However, the supplemental technology--
specifically, the in-situ bioremediation--will require pilot
testing prior to implementation.
Cost: The selected remedy is cost effective. The estimated
capital, annual O&M and total present worth cost of each
alternative are presented below.
All Costs in $1,000
Remedial
Alternative Capital Annual O&M Present Worth
S-6 5,847 154 7,300
G-16 720 2,100 37,900
Costs will further be modified at the final design stage to
reflect any changes made during design. Annual costs for
operation and maintenance of the soil remediation system are
expected to be approximately $154,000 per year in 1994 dollars.
Costs for maintenance of the infiltration and injection points,
and the vapor extraction system will be modified at the final
design stages to reflect any changes in costs due to design
modifications. Although some of the soils and groundwater
remedial alternatives had lower total costs, they did not provide
the same level of long-term effectiveness in protecting human
health and the environment. The estimated present worth of S-6
and G-16, the selected alternatives combined, is $45,200,000.
state acceptance: DTSC is the lead agency which has been
responsible for overseeing the RIfFS for the site. After
considering comments, DTSC finalized its selection of a remedial
action for the Site in its RAP. The RAP was issued on April 18,
1994. EPA selects and concurs with the remedy chosen in the
State's RAP.
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community acceptance: In October, 1993 DTSC, released a proposed
plan and RIfFS for the site. Site documents were made available
at the lead agency offices and a local repository, the public
library in Visalia. A public notice was published allowing 30
days for public comment on the RIfFS and Proposed Plan. A public
meeting was held on October 19, 1993 to describe the proposed
remedy and receive comments. No members of the public were
present at the public meeting. The decision for this Site is
based upon the Administrative Record.
10. Statutory Determinations
The selected remedy is protective of human health and the
environment, complies with ARARs, and is cost effective. Because
this remedy will result in hazardous materials remaining on-site,
a review will be conducted five years after the commencement of
remedial action, and every five years thereafter, to ensure that
the remedy continues to provide adequate protection of human
health and the environment.
11. Documentation of Siqnificant Chanqes.
~he proposed plan for the Site was released for public
comment in October, 1993. The proposed plan identified
alternatives S-6 (soil capping and in-situ bioremediation), and
G-16 (ex-situ treatment and in-situ bioremediation) together as
the preferred alternatives. DTSC reviewed all written comments
submitted during the comment period. Upon review of these
comments, DTSC determined that no significant changes to the
remedy, as it was originally identified in the proposed plan,
were necessary. EPA concurs with DTSC's determination.
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