United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R09-93/091
June 1993
&EPA Superfund
Record of Decision
Liquid Gold Oil, CA
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50272-101
REPORT DOCUMENTATION 1" REPORT NO. 2. 3. Reclplenra AccMaIon No.
PAGE EPA/ROD/R09-93/091
4. Thla and Subtitle 5. Raport Dat,a
SUPERFUND RECORD OF DECISION 06/21/93.
Liquid Gold Oil, CA 6.
First Remedial Action - Final
7. Author(a) .8. Parforinlng Organization Rapt. No.
9. Performing Organization Name and Addr... 10 Project Taak/Work Unit No.
11. Contract(C) or Grant(G) No.
(C)
(G)
12. Sponsoring Organization Name and Add,..a 13. Type of Raport & Period eovar8d
U.S. Environmental Protection Agency
401 M Street, S.W. 800/800
Washington, D.C. 20460 14.
15. Supplementary Notas
PB94-964517
16. Abstract (Limit: 200 words)
The 18-acre Liquid Gold Oil site is an inactive used oil and solvent collection and
transfer facility in Richmond, Contra Costa County, California. The site is bounded by
Hoffman Marsh to the east and southeast and by drainage channels connecting to San
Francisco Bay on th~ west and southwest. From 1965 to 1980, the site operated as a
used oil and solvent collection, storage, and transfer facility. Since 1982, the
property owner performed several interim remedial measures at the site. These actions
included removal of 25 bulk storage tanks, 73 drUms containing hazardous wastes, 760
yd3 of contaminated soil; and any remaining structures, debris, and asbestos for
offsite disposal at RCRA facilities. This. ROD addresses a final . remedy for the
remaining onsite low-level contamination in soil, sediment, and debris. The primary
contaminants of concern affecting the soil~ sediment, and debris are organics,
including PAHs; and metals, including lead.
The selected remedial action for this site inclu!ies removing offsite approximately
1,000 yd3 of contaminated sediment and debris from the drainage channels leading to the
Marsh to mitigate past impacts from the site; consolidating the sediment onsite;
installing a RCRA-h~brid soil cap over the contaminated onsite soil, and grading and
(See Attached Page)
17. Document Analysis a. Descrlptora
Record. of Decision - Liquid Gold Oil, CA
First Remedial Action - Final
Contaminated Media: soil, sediment, debris
Key Contaminants: organics (PAHs), metals (lead)
b. IdentifieralOpen-Endad Tarms
c. COSATI FleldlGroup
18. Availability Statement 19, Security Class (ThIs Report) 21. No.olPagas
None 16
20. Security Class (ThIs Pag,,) 22. Price
None
(See ANSI.Z39.18)
S..lnstructions on Reverse
OPTIONAL FORM 272 (4-77)
(Formerly NTI8-35)
Department 01 Commerce
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EPA/ROD/R09-93/091
Liquid Gold Oil, CA
First Remedial Action - Final
Abstract (Continued)
vegetating the site to control runoff; monitoring ground water; and implementing
institutional controls, including deed restrictions. The estimated present worth
this remedial action is $800,000.
cost for';
PERFORMANCE STANDARDS OR GOALS:
Not provided.
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RECORD OF DECISION
Liquid Gold oil Corp. Superfund Site
Richmond, California
EPA ID# CAT000646208
PART I - DECLARATION
statement of Basis and Purpose
This Record of Decision ("ROD") presents the selected
remedial action for the. Liquid Gold Oil Corporation Superfund
site (lithe Site") in Richmond, 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. 559601 et seg., 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 substances 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.
DescriDtion of the Remedy
The Liquid Gold oil Corporation operated a used oil and
solvent collection, storage and transfer facility from 1965 until
1980. Interim remedial measures, begun in 1982, have included
the removal of 25 storage tanks, 73 drums, 760 cubic yards of
contaminated soils, and.all remaining structures and debris. All
of these hazardous substances were disposed of offsite at RCRA
facilities. These interim response actions addressed the
principal threats at the site. The final remedy addresses
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threats remaining after the interim measures.
components of the selected remedy include: .
A deed restriction prohibiting residential development;
Grading, addition of soil, and seeding to control" runoff
patterns; .
Groundwater monitoring for a minimum of five years; and
Removal of sediments and debris from two drainage channels
leading to the adjacent marsh to mitigate possible past
adverse impacts from Liquid Gold.
The major
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 (IlARARslf) 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.
'.2/- 9~
Date
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PART II - DECISION SUMMARY
Liquid Gold Oil Corp. Superfund Site
Richmond, California
A detailed analysis of the selected remedial action for the
Liquid Gold Site is contained in the RAP prepared for DTSC in
March, 1993. The Site information summarized belpw is discussed
fully in the RAP. After considering public comments, the State
adopted the draft RAP, without change, 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 Liquid Gold Oil Corporation Superfund site is located in
the City of Richmond, Contra Costa County, California, west of
Interstate 580 and southwest of the Bayview West interchange.
The Site is bounded by Hoffman Marsh on the east and southeast,
and by drainage channels connecting to San Francisco Bay on the
west and southwest. The area of the Site is approximately 18
acres.
The Site is currently fenced and unoccupied. Current and
expected future zoning of the Site permits only commercial and
industrial uses. Land use restrictions selected as part of the
site remedy will also permit only commercial and industrial uses
in the future.
2. Site History and Enforcement Activities.
The Site is owned by Southern Pacific Transportation Company
("SPTCo") and was leased to several tenants from the 1940s to the
early 1980s. An asphalt manufacturing plant was operated on the
Site in the 1940s and '50s. Later the Site was leased to the
Liquid Gold Oil Corporation ("Liquid Gold"), which operated an
oil and solvent collection, storage and transfer facility.
In the 1970s and early '80s, investigations by the San Francisco
Bay Regional Water Quality Control Board and the U.S. Coast Guard
documented spills of oil and chemicals at the Site. Liquid Gold
cleaned up some surface spills after ceasing operations in 1980,
and then abandoned the facility. The Site was placed on the
California State Superfund List in January 1983, and on the
National Priorities List ("NPL") in September, 1983.
The property owner, SPTCo, performed a number of interim
response actions prior to and after California and NPL listing.
These actions have included the removal and off-site disposal of
25 bulk storage tanks in 1982 and '83; the removal and off-site
disposal of 73 drums of hazardous waste in 1984; the excavation
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and off-site disposal of 760 cubic yards of contaminated soil;
and the demolition of remaining ,site buildings and off-site
disposal of the demolished buildings along with some asbestos
contaminated debris, in 1989. On January 13, 1988, DTSC issued
a Consent Order to SPTCo requiring completion of an RIfFS for the
Site.
3. Hiahliahts of Community Participation.
Three fact sheets have been released describing activities
at the Site. In February, 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, and a public
notice was published allowing 30 days for public comment on the
RIfFS and Proposed Plan. A public meeting was held on March 30,
1993 to describe the proposed remedy and receive comments. Four
members of the public asked questions at the public meeting, and
two written comments were received from the community.. The'
comments were favorable. DTSC responsed to all comments received
during this period, which were primarily from other State
agencies, in the attached "Analysis of Public Comments." 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 the principal threats at the site. The selected remedy
addresses the low levels of contaminants remaining in soils and
groundwater at the Site, as well as sediments in drainage
channels leading from the site which may have been impacted by
past site operations.
5..site Characteristics.
site investigations have included sampling and analysis of
surface and subsurface soils, groundwater, surface water, and
marsh sediments.
.The soils at the site consist of 5-10 feet of fill material
over the original bay mud. The contaminants of potential concern
remaining in soils are lead and polycyclic aromatic hydrocarbons
("PAHS"). Average lead levels across the site are low (42 ppm)
and are well below the most stringent health-based levels for
residential use by children (370 ppb). One subsurface area of
approximately 5 acres in the center of the site contains elevated
lead levels. The average lead concentration in this area is 400
ppm. The average lead concentration in the most contaminated
layer (5 - 6.5 feet below ground surface) is 1,000 ppm. This
area also has the highest PAH levels onsite with an average of
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approximately 5 ppm. This area was identified as the area of
concern for the analysis of risks and remedial alternatives. PAH
levels for the rest of the Site are generally not detectable.
Due to the Site's proximity to San Francisco Bay, the
groundwater at the Site is naturally saline and is not a source
of drinking water under state or federal law. Average
concentrations of copper, lead, and nickel exceed the State basin
plan marine chronic water quality objectives by roughly a factor
of two.
The ecological assessment found evidence of biological
stress in at least one drainage channel leading away from the
Site. The resource agencies believe that there is also
sufficient evidence to demonstrate biological stress in another
drainage channel. Although chemical analyses do not clearly
establish a link with Site contaminants, the resource agencies
believe that the makeup of the biological communities in these
areas is indicative of petroleum contamination.
6- Summary of Site Risks.
The Site is currently fenced and unoccupied. Therefore, with
the exception of the trespasser scenario, the risks discussed
below are potential future risks rather than current risks. The
human health risk assessment demonstrated that the interim
remedial measures performed at the Site have reduced the level of
contamination to acceptable levels for all uses permitted under
current zoning. Contaminant levels are also acceptable for
trespassing children.
The risk assessment also considered the safety of a
hypothetical residential development even though residential
development would not be permitted under current zoning and is
not expected to occur. The results indicate that lead
concentrations, particularly in subsurface soils in the area of
concern, could cause unacceptable non-carcinogenic risks if
childhood residential exposure were to occur (using an uptake-
biokinetic model derived criteria of 370 ppm). However, the
maximum lifetime cancer risk levels are within EPA's range of '
acceptable risk under both residential and commercial scenarios.
The risk assessment results are listed below. A hazard index
below 1 is acceptable for non-carcinogens. Lifetime risks in the
range of 10"4 to 10~6 are acceptable for carcinogens.
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Risk Assessment Results
Hazard :Index
site Wide. Area of Concern
Child
Child
Adult
Adult
residential
trespasser
residential
commercial
<1
<1
<1
<1
6
<1
<1
<1
. Lifetime Cancer Risk
site Wide Area of Concern
Residential
Commercial
1x10-S
3X10-6
1x10-4
3X10-s
As is usual in risk assessments, the values above are based
upon a number of conservative assumptions. .The actual risks are
likely to be lower, and may in fact be zero. The carcinogenic
risk assessment is particularly conservative because it used .an
un-updated IRIS (EPA's Integrated Risk Information System
database) value (the revised IRIS value for benzo(a)pyrene
indicates less carcinogenic potency) and assumes that all PARs
have equivalent potency. Using current EPA assumptions, the
maximum calculated risks would be significantly lower.
7. Description of Alternatives.
I.
Alternatives were analyzed. to .address three media at the
site; soils, groundwater, and the drainage channels leading to
the marsh. The alternatives are listed in Table 1, "Remedial
Alternative Selection." A brief narrative summary of the
alternatives is presented below. Each alternative is described
in detail in the state's RAP.
Soils: As discussed in the risk assessment summary above, the
interim remedial measures addressed the principle threat soil at
. the Site, and current soil contamination levels are acceptable
for current and reasonably expected future non-residential uses.
The alternatives analyzed for soils include those which provide
remediation appropriate to the Site's current and expected uses
(institutional controls and containment options), and those which
would 90 further and remediate the Site for residential use
(excavation and treatment/disposal options). As required by the
NCP, a no-action alternative was also considered as a baseline
for comparison.
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The action alternatives which are appropriate to the current
and reasonably expected future pon-residential uses include.
institutional controls, a full RCRA cap and a RCRA-hybrid cap
(alternatives A-2-4 and B-2-5). . continued groundwater monitoring
would be a component of each of these alternatives. The
institutional controls alternative consists of a deed restriction
prohibiting future residential development and fencing. The
RCRA-hybrid cap alternative would include the addition of a layer
of clean soil over the surface of the site, and grading and
revegetating of the soil cap to direct rainfall away from
contaminated areas, prevent ponding, and further isolate
contaminants. The average estimated cost for the hybrid cap
would be approximately $600,000. The full RCRA cap alternative
would consist of a cap five feet thick and would include a clay
barrier, flexible membrane, and gravel and soil layers. Its
estimated average cost would be approximately $1.3 million. Both
capping alternatives would also include imposition of deed
restrictions to prevent residential development in' the. future.
The action alternatives which would allow future residential
uses include excavation and treatment or disposal of an
approximately five acre area of the most contaminated Site soils
(alternatives A-5-7 and B-6-8). The soil lead cleanup level for
these alternatives, 370 ppm, was derived from the risk assessment
anaiysis of the lead cleanup level necessary to protect children
living onsite in the area of contamination. The average
estimated cost of excavation and treatment with contaminants left
on-site (solidification) would be $3 million, excavation and soil
washing with off-site disposal of washed soil would be $5
million, and excavation and off-site disposal alone would be $7
million.
There are no chemical-specific ARARs for cleanup of the site
soil contaminants. The above-described lead cleanup level is a
to-be-considered criterion that was risk-based. California's
hazardous waste facility closure requirements, 22 California Code
of Regulations ("CCR"), Chapter 14, Article 7, "Closure and Post
Closure," (equivalent to 40 CFR Part ~64, Subpart G) are relevant
and appropriate requirements for the remedial alternatives that
do not involve excavation and treatment or disposal of .
contaminated soil. Since the closure requirements are relevant
and appropriate rather than'applicable, CERCLA guidance allows
consideration of "alternate" or "hybrid" closure if appropriate
to particular site conditions. Conditions at this Site are
appropriate for hybrid closure because the soil contaminant
levels have been reduced to acceptable concentrations for current
and expected uses, groundwater is naturally non-potable, and the
low level groundwater contaminants are not moving off-site.
Groundwater: Alternatives analyzed for groundwater include no-
action, continued monitoring for a minimum of five years, and two
types of barriers around the areas with elevated contaminant
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concentrations: a slurry wall and interceptor-trenches.
Groundwater monitoring would still be required if a barrier were
installed.
There are no chemical-specific ARARs applicable to site
groundwater. The RI found that on-site groundwater.
concentrations exceed federal (40 CFR144.3) and state (SWRCB.
Resolution No. 88-63) limits for salinity because of the Site's
proximity to the bay. Since Site groundwater may enter the bay,
the State's Water Quality Objectives (marine chronic criteria,
MCC) for the bay were reviewed as potential to-be-considered
(TBC) criteria for the groundwater/surface water interface. As
discussed previously, Site groundwater exceeds the MCCs for
copper, lead and nickel by a factor of two. CUrrent groundwater
monitoring' data does not indicate movement of contaminants off-
site. Therefore, no cleanup standard has been adopted.
The cost of continued groundwater monitoring would be
approximately $200,000. The costs of a slurry wall and
interceptor trenches with continued groundwater monitoring
be roughly $700,000 and $800,000, respectively.
would
Marsh Drainaqe Channels: The RI found evidence of possible
biological stress in two drainage channels leading away from the
Site. Effects are most evident at the upper end of drainage
channel 6. Although adverse effects c~nnot be conclusively
linked to site chemicals, the resource trustees believe benthic
populations present in drainage channell, are typical of those
. found in areas which have been subject to petroleum
contamination. The alternatives analyzed included excavation of
the upper end of transect 6 (up to 150 cubic yards) at a cost of
approximately $50,000, and excavation of both transects 1 and 6
(up to 1,000 cubic yards) at a cost of .approximately $200,000.
Sediments would be sampled prior to disposal either onsite or in
a landfill. Current sampling results do not indicate the
presence of any chemicals at concentrations which would require
hazardous waste disposal.
ARARs for the removal of the marsh sediments include the
state coastal zone management program comprised of the McAteer~
Petris Act and the San Francisco Bay Plan. The coastal zone
management program is intended to halt indiscriminate filling of
the bay and to help preserve and maintain the bay's ecological
integrity. section 307(c) (1) of the C~astal Zone Management Act
requires that federal agencies conducting or supporting
activities directly affecting the coastal zone, conduct or
support those activities in a manner that is consistent with
approved State coastal zone management programs. Any marsh
remediation activities would have to comply with the substantive
requirements of the state program. The California Department of
Fish and Game regulations also prohibit actions which would allow
petroleum constituents to enter state waters. The marsh
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alternatives are not expected to cause release of any petroleum
constituents. .' , '
8. Summarv of ComDarative Analvsis of Alternatives.
Each alternative has been analyzed with respect to the NCP's
nine criteria. A detailed analysis is presented in the state's
Remedial Action Plan. The comparative analysis will be
summarized here for alternatives addressing soils, groundwater,
and marsh drainage channels. '
Soil: The no-action alternative was determined not to meet the
NCP's primary criteria because contaminants remain at levels
which do not permit completely unrestricted (i.e. residential)
use of the site. Although future residential use is not
allowable under current zoning and is not anticipated, a deed
restriction prohibiting residential development is necessary to
ensure, long-term protection of human health.' .
The two capping alternatives analyzed, a hybrid landfill cap
and a fullRCRA cap, meet the relevant and appropriate
requirements of hazardous waste closure regulations. However, in
light of Site conditions, DTSC and EPA agreed that a full RCRA
cap was unnecessary and did not provide additional protectiveness
or risk reduction to justify the higher cost. The caps reduce
potential exposure to contaminated soils and reduce the
infiltration of rainwater which could potentially leach
contaminants from the soil. The hybrid cap is as protective as
the full RCRA cap because groundwater beneath the Site is not
potable, and current monitoring does not indicate transport of
chemicals off-site through groundwater. The hybrid cap will also
cause fewer short-term impacts during construction and less
interference with any future non-residential development of the
site. '
The excavation and treatment or disposal options are
significantly more expensive than the options above but do not
provide significant reductions in risk. These alternatives' are
not necessary because the interim remedial measures have reduced
contaminant concentrations to protective levels for uses
allowable under current zoning and reasonably expected future
use. '
Groundwater: current groundwater monitoring data do not indicate
that site contaminants are being transported off-site at levels
of concern. Therefore, the containment alternatives do not
provide significant advantages over continued monitoring.
Marsh Drainage Channels: Based on the results of the ecological
assessment, it appears that at least some sediments have been
impacted by Site contaminants. Therefore some excavation is
necessary for overall protection. Excavation of only the upper
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end of transect 6 would result in the least short-term impact to
existing biota in the drainage~. However, the resource agencies
have concluded that larger areas of both transects 1 and 6 have
likely been impacted by the past operations of Liquid Gold, and
that the existing biological populations in the drainages are
indicative of a polluted environment. Excavation of both
drainages would therefore provide greater long-term protection.
9. Selected Remedv.
The major components of "the selected remedy include:
A ~eed restriction prohibiting residential development;
Grading, addition of soil, and seeding to control runoff
patternsj . .
Groundwater monitoring for a minimum of five yearsj and
Removal of sediments and debris from two drainage channels
lea~ing to the adjacent marsh .to mitigate possible past
adverse impacts from Liquid Gold.
The selected remedy provides overall protection of human
health and the environment, complies with ARARs, and prov~des the
best overall balance of alternatives under the nine selection
criteria of the NCP. The analysis of the selected remedy with
respect to the nine criteria is summarized below.
OVera1.l protection of human health and the environment: The
selected remedy provides appropriate overall protection of human
health and the environment, given the low levels of contaminants
which remain onsite. Interim response measures performed prior
to the RIfFS removed all hazardous substances which may have
presented principal threats to human health. The risk assessment
indicated that Site conditions are ~cceptable for uses allowable
under current zoning and reasonably expected future uses. A deed
restriction will provide additional assurance that residential
development will not occur. Groundwater monitoring indicates
that Site contaminants are not being transported offsite. site
grading and continued monitoring will provide additional
assurances that contaminants do not move offsite through
groundwater. Removal of debris and sediments from poterltially ,
impacted marsh drainages will improve tidal action and permit
.long-term recolonization by marsh biota.
Compliance with ARARs: The.major ARARs identified for the
selected remedy include the closure requirements of the.
California Hazardous Waste Control Law C"HWCL1t), and the Coastal
Zone Management Act C"CZMA"), 16 U.S.C. S1451, et seq. HWCL .
closure requirements are relevant and appropriate, rather than
applicable to the site. Because the site is more closely
analogous to a landfill unit than to any other type of RCRA unit,
the relevant and appropriate analysis focused on the landfill
closure requirements of 22 CCR 66264.310 and the "alternate-
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landfill" or "hybrid" closure described in the proposed revisions
to the NCP, 53 FR 51446, and in EPA's ARARs guidance (Volume I,
p. 2-20). .
"
The guidance describes the following conditions as
appropriate for implementation of hybrid closure: residual waste
material at a site poses a direct contact threat but does not
pose a threat to groundwater; and, residual leachate
contamination does not exceed health-based levels. The hybrid
closure to address this scenario consists of a permeable cover to
address the direct contact threat and limited long-term
management, including site and cover maintenance, groundwater
monitoring and institutional controls, including land use
restrictions. Conditions at the Liquid Gold Site are such that
hybrid closure is appropriate. The selected remedy for soil
satisfies this ARAR.
The_remedial activities considered for restoration of
sloughs leading from the site into Hoffman Marsh and the Bay
would directly affect the coastal zone. Section 307(C) (1) of the
CZMA requires that federal agencies conducting or supporting'
activities directly affecting the coastal zone, conduct or
support those activities in a manner that is consistent wi~h
approved State coastal zone management programs. Under CERCLA,
on-site activities are not'subject to administrative review or
permitting processes, but they must be consistent with the
substantive requirements of the coastal zone management plan.
The approved coastal zone management program for San Francisco
Bay includes the McAteer-Petris Act and the San Francisco .Bay
Plan, and is administered by the San Francisco Bay Conservation
and Development Commission.
The McAteer-Petris Act and the Bay Plan were developed
primarily to halt uncontrolled development and filling of the
Bay. Their broad goals include reducing bay fill and disposal of
dredged materials in the Bay, and maintaining water quality and
the ecological integrity of the Bay.
The remedial action selected for the marsh areas at the site
was designed by the agencies supporting DTSC, including the
California Department of Fish and Game, the Regional Water
Quality Control Board and the National Oceanic and Atmospheric
Administration, after consideration of ecological studies of the
Hoffman Marsh and drainage channels leading from the site into
the marsh. The selected remedial action includes removal of
flotsam from the drainage'channels, and excavation and disposal
of roughly 1,000 cubic yards of sediments which may have been
impacted by the Site. The sediments will be disposed of in a
non-tidal location. '
The purpose of the selected remedy is to improve the
ecological value of the drainage channels leading into Hoffman
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Marsh and to mitigate any adverse impacts which may have resulted
from past Site activities. The actions will not reduce the area
of the Bay or result in any filling of the Bay, and are
consistent with the coastal zone management plan. Therefore, the
selected remedy satisfies the requirements of Section 307(c) (1)
of the CZMA.' /
Long~term effectiveness and permanence: Interim response actions
at the Site have reduced contaminant concentrations to levels
which are acceptable for direct human exposure under current
zoning and reasonably expected future use. A deed restriction
prohibiting residential development will provide additional
assurance of long-term effectiveness. Site groundwater is
naturally unpotable due to salinity. Groundwater monitoring
results show slightly elevated levels of some metals with respect
to San Francisco Bay standards, but do not indicate that .
contaminants are moving off-site through groundwater. Grading
the Site~to control runoff patterns and reduce ponding in areas
with elevated metals concentrations will further reduce the
potential for 'transport of contaminants through groundwater.
continued groundwater monitoring will provide additional .
assurance that offsite migration does not occur. Marsh sediments
which may have been impacted by past Site operations will be
excavated to imp~ove tidal action and permit long-term. .
recolonization by marsh biota. .
Reduction of toxicity, mobility, or volume through treatment: The
selected remedy does not include treatment. The NCP (55 FR 8846,
March 8, 1990) indicates that "EPA expects to use treatment to
address the principal threat posed by a site, whenever
practicable" and "...to use engineering controls, such as
containment, for waste that poses a relatively low long term
threat or where treatment is impraoticable." The interim
response measures, which addressed the concentrated wastes which
may have presented principal threats at the Site, were performed
prior to SARA and the inclusion of the statutory preference for
treatment in CERCLA S121. The selected remedy for the low levels
of hazardous substances remaining onsite meets the NCP
expectation for engineering controls rather than' treatment of
wastes that pose low level long term threats.
Short-term effectiveness:. The selected remedy will not pose any
risk to the community during implementation. Potential risks to
onsite workers will only be those physical hazards. associated
with earth grading operations. Environmental impacts during
remediation should also be minimal. The RCRA-hybrid cap selected
for onsite soils will cause much less disturbance of existing
vegetation than would either. the full RCRA cap, or excavation 'and
treatment or disposal options. The selected marsh remediation by
excavation of sediments from draina~e channels 1 and 6 will cause
loss of existing biota in the short term. However, the resource
agencies believe that the existing biota is dominated by
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pOllution-tolerant species and that a more diverse benthic
population will recolonize the channels after remediation.
selected remedy is expected to take 120 days to implement.
Implemen~abili~y: The selected remedy is readily implementable.
The selected remedial activities for Site soils and marsh
drainage sediments will be accomplished using conventional earth-
moving equipment. The effectiveness of continued containment of
hazardous substances in soils will be determined using existing
groundwater monitoring wells.
The
Cos~: The selected remedy is cost effective. The cost of the
proposed RCRA-hybrid cap will be approximately $600,000 (capital
and 30-year.O&M): Other alternatives, such as a full RCRA cap
and excavation and treatment and disposal, have much higher costs
without providing increased protectiveness. given the low levels
of hazardous substances remaining onsite and the reasonably
expected future Site uses. The cost of excavation of marsh
drainages 1 and 6 is approximately $200,000 (capital and O&M).
Although this is higher than the cost of the other ~arsh
alternatives analyzed, the selected alternative provides greater
assurance of long-term effectiveness at a reasonable cost.
S~a~e accep~ance: DTSC is the lead agency which has been
responsible for overseeing the RIfFS for the Site. After
considering comments from the public, potentially responsible
parties, and other state agencies, all of which are included in
the attached Analysis of Public Comments, DTSC finalized its
selection of a remedial action for the site in its RAP. A copy
of the State's Remedial Action Plan Approval Record, dated June
3, 1993, is attached. EPA selects and concurs with the remedy
chosen in the State's RAP., .
communi~y accep~ance: A pUblic meeting to discuss and receive
comment on the proposed remedy was held on March 30, 1993.
Community members appeared satisfied with agency responses to
questions and with the selected remedy. The two written comments
from members of the community were favorable. Most of the
comments in the attached Analysis of Public Comments, prepared by
the lead State agency, DTSC, were made by other State agencies'
rather than members of the community.
10. statutorv Determinations
The selected remedy is protective of human health and the
environment, complies with ARARs, and is cost effective. The
principal threats at the site were addressed by interim remedial
measures. 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.
-13-
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~~. Documentation of Siqnificant Chanqes.
The proposed plan for the site was released for public
comment in February, ~993. ~he proposed plan identified.
alternatives A-3 (surface soils), B-3 (subsurface soils and
groundwater), and C-4 (marsh drainages) together as the preferred
alternative. DTSC reviewed all written and oral 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 has reviewed the comments and the
responsivene$s summary and concurs with DTSC's determination.
-~4-
I .
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. TABLE 1
REMEDIAL ALTERNATIVE SELECTION
UQUID GOLD SITE, RICHMOND, CAUFORNIA
~.~.::~;~;:;~;j:~:~~=~:~~~;~:.,;j;;;::'.':I.. ;"":':':/:,."':.'~'."':i~~~~.:~,~:::~::~;~tl~::~~0~1'.;~;:~:~~:;~~~:}~~~~:.~r:~~e~o~.U~;:
A.I No Aclion . None . Inadequate assurance of future protection of human
health if alloWable land use were to change
. Does not provide the additional assurances or the envi-
ronmenlal benefits of the proposed altcmati\'C
PROPOSED ALTERNATIVE (with 8.3)
. AppropriaIdy remcdiales poatiaI exposure to surmce soils
. Provides protection of human health and environment
. No significant benefits fIVer less apensi\'C proposed
aJlernative .
. Additional reduCtions in conlalninant concentJUions are
not necessary to procect human health or the envil'OtUl1l:llt
under current and apecred zoning and allowable land use
. Not necessary to proII!ct human beaIth or the environment
uncIer CUrTCIII and CtpCCIed zoning and allowable land use
. Concrete-like mass permanently limits future use of site
. Potential impact on wildlife habitat
. Excavation of surface soils in O.7-aere portion of sile . AdditioDal redlR:tions in comaminant c:onc:entrations are
. Offsite disposal of excavated soil not nec::essary to pl'Ol.CCt human health or the environment
. Placement of cleaD soil under current and etpecred zoning and allowable land use
';~~:,:;;j:~~F: ?:Wii ~ :,.,:~.:t;~~:;~/:$:U»StiRPAclf~il;$:iND\QR.q:tTNPWA~;: .'~.~:if:; :' i. ". . :;;1' -:::"::;\~;tZ~::":;;W~~~I~~tt!i;f;::?'1F
- . Groundwater monilOring . Inadequate assurance of future proteCtion of human
health if allowable land use were to change
. Does not provide the additional assurances or the envi-
ronmenlal benefits of the proposed allernati\'C
A.2
lastitutioaal Controls
A.3
Vegetated Soil CflVer
A-4
Capping.
A.S
Chemical Treatment
A-6
Physical Treatment
A.7
~tion
.
~~~i~7.,t~~~ ,
8.1
No Aclion
8-2
institUtional Controls
8.3
Vegelated Soil CO\'Cr
8-4
Capping
8.S
Capping Extended Activity
Area
8-6
Chemical Tratment
8-7
Physic:al Treatment
8-8
Excavation
8.9
Groundwater
Slurry WaD
B-I0
Groundwater
Inten:cptor Trench
ji:::.
';': .
C.l
No Action
C-2
Institutional Controls
and Mitigation
C.3
EJtcavation of Upper
End of Southwest
Drainage Channel
Removal of Sediments
from Southwest Drainage
Channel and Upper End
of Southeast Drainage
Channel
C-4
. Deed restriction
. Fencing
. Grading to control runoff patterns
. Plac:ement of up to 2 fe:et of clean fill
. Provide wgeIated COYer by seeding area with nati~ plants
. Institutional controls
. S-foot thick cap OYer O.7.acre portion of site
. Institutional controls
. Excavation of surface soils in O.7-acre portion of site
. Soil washing to remove c:hemicals
. Replacement of soil
. Euavation of surface soils in O.7-aere portion of site
. Soil solidification to immobiliu: chemicals
. Replacement of solidified soil
. Groundwater monilOring
. Deed restriaion
. Fencing
. Grading 10 control runoff patterns
. Plac:ement of up to 2 fe:et of clean fill
. Provide wgeIated COYer by seeding area with nati~ plants
. Glpllndwater monitoring
. Institutional controls
. S.foot thick cap OYer S-ac:re portion of site
. Groundwater monitoring
. Institutional controls
. S-foot thick cap OYer extended activity area
. Groundwater monitoring
. Institutional controls
. Excavation of subsurface soils in S-ac:re portion of site
. Soil washing to remOYe chemicals
. Replacement of soil
. Groundwater monitoring
. Institutional controls
. Excavation of subsurface soils in S.ac:re portion of site
. Soil solidification to inunobiliu: chemicals
. Replacement of solidified soil
. Groundwater monitoring
. Institutional controls
. Excavation of subsurface soils in S.acre portion of site
. Offsite disposal of excavated soil
. Placement of clean soil
. Groundwater monitoring
. Institutional controls
. Construaion of slurry wall
. Groundwater monitoring
. Institutional controls
. Construction of trench
. Groundwater monitoring
. Institutional controls
MARSH
. None
. Access controls to prevent disturbance of marsh
. Removal of debris to improve tidal action in upper ends
of drainage channels
. EJtcavation of upper end of southwest drainage channel
. Removal of debris to improve tidal action in upper ends
of drainage channels
. Removal of sediments from southwest drainage channel
and upper end of southeast drainage channel
. Removal of debris to improve tidal action in upper ends
of drainagc channels
. Post clean-up sampling of remaining sediments
PROPOSED ALTERNATIVE (with A-3)
. Appropriately remediates potenlial aposure to subsur-
face soils
. Provides protection of human health and environment
. No significant benefilS fIVer less apensi\'C proposed
alternative
. No significant benefits over less expensi\'C proposed
aJlemative
. Additional reductions in contaminant concentrations are
not necessary 10 protect human hcalth or the environ.
ment under c:urrent and expected zoning and allowab!e
land use
. Not necessary to pl'OlCCt human heallh or the environment
uncIer cunatt and CtpCCIed zoning and allowable land use
. Concrete-like mass pennanently IimilS futUre uses of the
site
. Potential impact on wildlife habitat
. Additional reductions in contaminant concentrations are
not necessary to protect human health or the environ-
ment under c:urrent and apected zoning and allowable
land use
. Groundwater containment does not appear necessary to
protect human health or the environment gi\'eR aisting
groundwaler data. Groundwater monitoring will con-
tinue under the proposed alternative
. Groundwater containment does not appear necessary to
proted human health or the environment gi\'Cn aisting
groundwater dala. Groundwater monitoring will con-
tinue under the proposed alternative
. . '.:.
. Does not meet regulatory requirements (ARARs)
. Not protedive of environment
. Does not remediate area of marsh (southwest drainage
channel) that may be affec:ted by chemicals from Liquid
Gold activities
. May not mitigate impacl~ to marsh in southeast drainage
channel
PROPOSED ALTERNATIVE
. Remediatcs
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