PB96-963115
EPA/AMD/R03-96/235
March 1997
EPA Superfund
Record of Decision Amendment:
Rentokil, Inc.,
(VA Wood Preserving Division)
Richmond, VA
8/27/1996
-------
RECORD OF DECISION AMENDMENT
RENTOKIL, INC.
Declaration
Site Name and Location
Rentokil, Inc.
Henrico County, Virginia
Statement of Basis and Purpose
This decision document revises the Record of Decision (ROD)
signed on June 22, 1993, for the Rentokil, Inc. Site (Site), in
Henrico County, Virginia. The revised remedy was chosen in
•accordance with the requirements of the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980,
as amended (CERCLA), 42 U.S.C. § 9601 et seg.r and, to the extent
practicable, the National Oil and Hazardous Substances Pollution-
Contingency Plan (NCP), 40 C.F.R. Part 300. This decision
document explains the factual and legal basis for revising the
remedy for this Site. The information supporting this remedial
action decision is contained in the Administrative Record for
this Site.
The Virginia Department of Environmental Quality concurs with the
amended remedy.
Assessment of the Site
Pursuant to duly delegated .authority, I hereby determine,
pursuant to Section 106 of CERCLA, 42 U.S.C. §9606, that actual
or threatened releases of hazardous substances,' pollutants or
contaminants from this Site, if not addressed by implementing the
response action selected in this Record of Decision, may present
an imminent and substantial endangerment to public health,
welfare, or the environment.
Description of the Selected Remedy
This ROD•Amendment revises the remedy previously selected by
deleting the requirement for treatment of "hot spots" at the
Site. This ROD Amendment will be the final Record of Decision
for the Site. The principal threats associated with the "hot
-------
spots" are contaminated soils containing hazardous substances.
The amended remedy includes the following major components:
(1) Demolition of Existing Structures
(2) Removal of Unlined Pond
(3) Drum disposal
(4) Soil Consolidation Prior to Capping
(5) Construction of Multilayer Cap, Slurry Wall, and Dewatering
System
(6) Sediment Excavation and Disposal
(7) Institutional Controls
(8) Ground Water Monitoring
Declaration of 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 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 it
satisfies the statutory preference for remedies that employ
treatment that reduces toxicity, mobility, or volume as a
principal element.
Because this remedy will result in hazardous substances remaining
onsite above health-based levels, a review will be conducted
within five years after commencement of remedial action to ensure
that the remedy continues to provide adequate protection of human
health and the environment. Such reviews will be conducted every
five years thereafter until EPA determines that the cleanup
levels set forth in this ROD have been achieved, or that the
hazardous substances remaining at the Site do not prevent
unlimited use and unrestricted exposure at the Site.
Thomas C. Voltag/fio S ~.^> Date
Director, Hazardowe-(Wa>fetf"*Management
Region III
-------
DECISION SUMMARY
A. INTRODUCTION
The Rentolcil Inc. Site (the Site) is located at 3000 Peyton
Street at the intersection of Peyton Street and Ackley Avenue in
Henrico County, near Richmond, Virginia (see Figure 1 - Regional
Location Map). The Site is a former wood treating facility which
ceased operating in January 1990. The land immediately
surrounding the Site is mostly open space/woodlands. Nearby
development is comprised of light industrial, commercial, and low
density residential. The Site and surrounding land are presently
zoned for light and general industry. For more information on
the Site name, Site location, Site description, Site history,
enforcement activities, and community participation activities
conducted prior to June 1993 refer to Sections A through C of the
Record of Decision issued on June 22, 1993.
The U.S. Environmental Protection Agency (EPA) is the lead *
agency for response activities at the Site. The Virginia
Department of Environmental Quality (VDEQ) is the support agency
for this response action.
On January 8, 1993, EPA released the original Proposed Plan
for the Site, requesting public comment on the alternatives
identified at that time to remediate contamination at the Site,
as well as the EPA preferred alternative. Based on comments
received, EPA, in consultation with VDEQ, selected the remedy to
clean up the Site on June 22, 1993 in the Record of Decision
("ROD"). The ROD describes the remedial action to be taken to
address contamination at the Site. A description of the major
components of the remedy is provided in Section C, below.
The requirement for treatment of hot spots has been deleted
because ground water modeling demonstrates that, following
construction of the cap and slurry wall and operation of the
dewatering system, contaminants in .the soil will be effectively
immobilized and will not move away from the Site in the
groundwater. Thus, treatment of hot spots is unnecessary.
B. Community Participatipn and Information Availability
The Proposed Plan describing the amended remedy was released
to the public for comment on May 4, 1996. The Proposed Plan was
-------
FIGUHI 1
REGIONAL LOCATION MAT
-------
made available to the community in the information repositories
maintained at the EPA Docket Room in Region III and at the
Henrico County Municipal Reference and Law Library. The. notice
of availability was published in the Richmond Times on May 4,
1996. In addition, a public meeting was held on May 14, 1996 in
the Board of Supervisors Board Room at the Henrico County
Government Complex, Parham Road at Hungary Spring Road. At this
meeting, representatives from EPA and the VDEQ answered questions
about conditions at the Site and the amended remedial alternative
preferred by EPA. The public comment period on the Proposed.Plan
was held from May 4, 1996 to June 4, 1996. A response to the
comments received during this period is included in the
Responsiveness Summary, which is part of this ROD Amendment.
These activities were undertaken by EPA as part of its public
participation responsibilities under Section 117(a) of the
Comprehensive Environmental Response, Compensation and Liability
Act of 1980 (CERCLA), and Section 300.435(c) (2) (ii) of the
National Oil and Hazardous Substances Pollution Contingency Plan
(NCP).
•
The Administrative Record for this Site' is maintained at the
following information repositories:
Henrico County Municipal U.S. EPA Docket Room
Reference and Law Library Ms. Anna Butch (3HW14)
County Government Complex Region III
Parham Road at Hungary Spring Road 841 Chestnut Building
Richmond, VA 23228 Philadelphia, PA 19107
Phone ft: 804 672-4780 Phone ft: 215 566-3157
The Administrative Record includes all documents upon which
the selection of the amended response action is based. In
accordance with Section 300.825(a)(2) of the NCP, this ROD
Amendment will become part of the Administrative Record.
C. SUMMARY OP ORIGINAL REMEDY
The remedy selected in the June 1993 ROD contained the following
major components:
(1) Demolition of Existing Structures
(2) Removal of Unlined Pond
-------
(3) Excavation and onsite treatment of "hot spots"
(4) Drum disposal
(5) Soil-Consolidation Prior to Capping
(6) Construction of a Multilayer Cap, Slurry Wall, and
Dewatering System
(7) Sediment Excavation and Disposal
(8) Institutional Controls to prevent residential use of the
Site and use of the ground water.
(9) Ground water monitoring
D. RATIONALE FOR CHANGING REMEDY SELECTED IN 1993 ROD
As part of the remedial design, Rentokil, Inc. performed a -
Value Engineering analysis to evaluate the cost-effectiveness of"
the design. Ground water modeling was performed as part of this
analysis to evaluate the movement of the existing
pentachlorophenol contaminated ground water plume. This modeling
demonstrated that, following construction of the containment
system-cap and slurry wall-and operation of the dewatering
system, ccr.'-.aminants in the soil will be effectively immobilized
and will n~- move away from the containment area in the ground
water. E?« has reviewed the ground water modeling and agrees
wit.h its conclusions.
Because the Site is underlain with a tight bedrock, keying
the slurry wall into the bedrock near the perimeter of the Site
will form, a low permeability barrier. Construction of a RCRA
Subtitle C cap- over the area of the former wood treatment
facility will effectively prevent precipitation from permeating
through the- soil. Finally, operation of the dewatering system
will remove whatever ground water is present under the cap.
Once all of the.presently existing ground water is removed,
the dewatering system will form an inward gradient of ground
water into the containment area. Thus, contaminants in the
ground water will be prevented from dispersing away from the
-------
containment area. At the time EPA issued the ROD, EPA required
treatment of soils in areas where the highest levels of
contamination were expected. The findings from the ground water
modeling have demonstrated, however, that the containment system
designed for this Site would effectively prevent migration of the
existing contamination under the former wood treating a'rea and
that treatment of the "hot spots" is not warranted. As a result,
EPA has evaluated and agreed to change the cleanup plan for the
Site, removing the requirement for treatment of "hot spots" prior
to construction of the cap and slurry wall.
E. DESCRIPTION OF REVISED REMEDY
The proposed amended remedy contains the following major
components (all of which were part of the originally selected
remedy):
(1) Demolition of Existing Structures: Existing structures at
the Site will be demolished, decontaminated, and transported
offsite for disposal.
(2) Removal of Unlined Pond: Surface water in the unlined pond
will be removed, treated to safe levels through onsite
carbon adsorption, and discharged to North Run Creek.
Approximately 70 cubic yards of K001 waste will be excavated
and transported offsite to be incinerated (onsite
dechlorination of waste will be performed if required prior
to offsite incineration). The unlined pond will then be
closed in accordance with Virginia Hazardous Waste
Management Regulations (VHWMR).
(3) Drum disposal: Any drums excavated from the Fill Area will
be disposed offsite.
(4) Soil Consolidation Prior to Capping: Site surface soils (0-
2 feet in depth) which lie outside the area to be capped and
exceed Site-specific cleanup levels (approximately 7,200
cubic yards) will be excavated and placed in the area of the
Site to be capped (generally, these soils occur in Wetlands
A, B, and C).
Soils in Wetlands A, B, and C will require dewatering prior
to excavation. Water from this process will be treated in
-------
the onsite water treatment system (discussed below) prior to
discharge to North Run Creek. Excavated wetlands will be
revegetated with appropriate plant species as approved by
EPA.
(5) Multilayer Cap, Slurry Wall, and Dewatering System
Construction: A multilayer RCRA Subtitle C cap will be
constructed over approximately ten acres of the Site where
contamination in the surface soil exceeds the Site-specific
cleanup levels. The cap will extend into the wetlands to
the extent possible. Wetlands lost due to capping will be
replaced. A slurry wall will be constructed around the
perimeter of the cap to ensure the contamination is
adequately contained. A dewatering system will be
constructed inside of cap/slurry wall to keep groundwater
within the slurry wall from building up and creating
pressure on the slurry wall and to treat any DNAPL
collected. Water from the system will be treated onsite by
carbon adsorption and, if necessary, precipitation of
metals. Treated ground water will be discharged to North -
Run Creek. The water will be treated to levels that meet
the substantive requirements of a Virginia Pollution
Discharge Elimination System (VPDES) permit.
(6) Sediment Excavation and Disposal: Sediments in the oxbow of
North Run Creek north of the Site will be excavated and
disposed in the area onsite to be capped. Sediments in
Talley's Pond and sediments previously dredged by the owner
of the Pond will be sampled. Sediments in or previously
dredged from Talley's Pond which exceed.the Site-specific
cleanup goals will be excavated, treated onsite by Low
Temperature Thermal Desorption (LTTD), and disposed offsite.
(7) Institutional Controls: Deed restrictions will be required
to prohibit residential development of the Site and/or use
of the ground water.
(8) Ground Water Monitoring: Long-term ground water monitoring
will be performed for at least 30 years.
-------
F. EVALUATION OF ALTERNATIVES
The following summary discusses the performance of the
proposed cleanup plan in terms of the nine evaluation criteria,
noting how it compares to the originally selected remedy. This
summary focuses only on the issue of how treating or not treating
the "hot spots" prior to capping affects the overall performance
of the cleanup plan since this is the only change proposed to the
remedy for the Site. The nine criteria can be categorized into
three groups: threshold criteria, primary balancing criteria, and
modifying criteria. The criteria associated with each category
are as follows:
THRESHOLD CRITERIA
Overall protection of human health and the environment
Compliance with applicable or relevant and appropriate
requirements (ARARs)
PRIMARY BALANCING CRITERIA
Long-term effectiveness
Reduction of toxicity, mobility, or volume through
treatment
Short-term effectiveness
Implementability
Cost
MODIFYING CRITERIA
Community acceptance
State acceptance
These evaluation criteria relate directly to the
requirements of Section 121 of CERCLA 42 U.S.C. § 9621 which are.
used to determine the overall feasibility and acceptability of
the remedy. Threshold criteria must be satisfied in order for a
-------
remedy to-be eligible for selection. Primary balancing criteria
are used to-weigh major trade-offs between remedies. Support
agency and community acceptance are modifying criteria which are
taken into account after public comment is received on the
Proposed Plan.
Overall Protection of Human Health and the Environment
Both the original and the revised cleanup plan provide overall
protection of human health and the environment. Under both
plans, the area of contaminated soil will be .covered with a RCRA
Subtitle C cap, thereby eliminating any direct contact with the
soil. Both plans are also effective in protecting further
migration of contamination to the groundwater.
Compliance with ARARs
The key ARARs associated with contaminated soil at the Site
are the RCRA Land Disposal Restrictions, 40 C.F.R. Part 268, that
limit the type and concentration of hazardous wastes that can be-
land disposed. These requirements are applicable when hazardous-
wastes regulated under RCRA are present at a Site and are being
placed in a land disposal unit or facility. Virginia also has
similar land disposal restrictions under its hazardous waste
management regulations. Although the Site soils contain
hazardous wastes regulated under RCRA (i.e. F032, F034, and F035
listed wastes which are drippage from wood treatment processes
which utilize PCP, creosote, or arsenic solutions, respectively),
RCRA Land Disposal Restrictions for these F wastes have not yet
been promulgated. The original cleanup plan, including the
provision of consolidating the wetland soil under the cap,
complied with all ARARs, including the RCRA land Disposal
Restrictions and the Virginia requirements. The RCRA Land
Disposal Restrictions and equivalent state regulations would not
apply since soils from the "hot spots" would not be excavated and
treated under the revised cleanup plan.
Long-Term Effectiveness and Permanence
The original cleanup plan provided a higher degree of long-
term effectiveness and permanence than- the revised remedy because-
the highest levels of contamination in the soil would have been
eliminated through treatment. However, the ground water modeling
-------
demonstrates that, because the hydrogeology of the area limits
migration of contaminated ground water, the cap and slurry wall
system, in conjunction with the dewatering system, will
effectively prevent further migration of contaminated ground
water at the Site because an inward gradient of ground water into
the Site will be created. Therefore, the revised cleanup plan is
considered equally protective over the long term as the original
plan. Both alternatives include treatment of the ground water
recovered by the dewatering system within the cap and slurry wall
and institutional controls prohibiting use of ground water and
residential development at the Site. In addition, because high
levels of contamination in the soil remain and there have been
discussions concerning non-residential development of the Site
after construction of the remedy is complete, design and
construction of the cap will take into account future development
of the Site so that the cap will not be disrupted after
construction is completed. Institutional controls will be
implemented to ensure that the integrity of the cap is
maintained. These requirements ensure the long-term
effectiveness and permanence of the selected remedy.
Short-Term Effectiveness
The revised cleanup plan would have fewer short-term impacts
than the original plan because the revised plan would take less
time to implement and will not create disruptions associated with
soil treatment (e.g. truck traffic, dust associated with
excavation, staging of the soil prior to and after treatment, and
the noise and emissions associated with the treatment system
itself).
Reduction of Toxicity, Mobility, or Volume through Treatment
The original cleanup plan would reduce the toxicity and
volume (though not mobility) of Site contaminants through
treatment to? a greater extent than the revised plan because the
highest levelsr of soil contamination would have been treated and
removed usincp low temperature thermal desorption. This added
reduction would not, however, increase the overall effectiveness
because, as discussed previously, the ground water modeling shows
mobility of contaminants in the ground water away from the Site
would be- the same under either action.
-------
Implementability
Overall, both the original cleanup plan and the revised plan
can be readily implemented, however, the revised plan is easier
to implement because on-site treatment of soils is not required.
Regarding the original cleanup plan, bench-scale treatability
testing conducted during the pre-design phase has shown that low
temperature thermal desorption can meet the health-based cleanup
levels for organics set forth in the ROD. If treatment standards
for F032, F034, and F035 listed wastes are promulgated prior to
cleanup at the Site,.the contaminated soil would have to be
treated to these new levels. Although low temperature thermal
desorption is likely to meet the new levels for organic
contaminants, treatment levels established for arsenic could be a
problem because arsenic is not effectively removed in the low
temperature thermal desorption process.
Cost
The .cost of the revised cleanup plan is approximately
$12,000,000 while the present estimate of the cost of the
original cleanup plan is approximately $22,500,000.
State Acceptance
VDEQ served as the lead agency for the Commonwealth of
Virginia for the C2RCLA response activities at the Rentokil, Inc.
Site. VDEQ has raviewed the remedial alternatives under
consideration for the Site and has provided EPA with technical
and administrative requirements for the Commonwealth of Virginia.
VDEQ has reviewed the amended ROD and concurs with the amendment
as discussed below.
Community Acceptance
The Proposed Plan to Amend the ROD was released on May 4,
1996 to solicit public comment regarding the proposed revised
cleanup plan. . At that time a 30-day comment period was opened.
A public meeting on the Proposed Plan was held on May 14, 1996 at
the Henrico County Government Complex. Although comments were
raised at the public meeting, no objections were voiced. The
comments are summarized in the Responsiveness Summary which is
included in this ROD Amendment. No written comments were
-------
submitted to EPA during the public comment period.
G. AMENDED REMEDY
Following review and consideration of the information in the
Administrative Record file, the requirements of CERCLA, the NCP,
and public comment, EPA has selected the revised cleanup plan as
the .selected remedy. Specifically, the selected remedy, which
satisfies Section 121 of CERCLA, 42 U.S.C. §9621 includes:
(1) Existing Structures
Demolition, decontamination, and offsite disposal of the
existing structures at the Site.
(2) Unlined Pond
Excavation and offsite incineration of approximately 70
cubic yards of K001 waste (including onsite dechlorination
if the level of dioxins/furans in the waste would cause a
violation of the incinerator's RCRA"permit if incinerated
without prior treatment).
Removal and onsite carbon adsorption treatment of the
surface water in the unlined pond with discharge to North
Run Creek; and closure of the 'unlined pond.
(3) Soil
Movement of Site surface soils (0-2 feet--approximately
7,200 cubic yards) which lie outside the area to be capped,
and which exceed any Site-specific cleanup level, to the
area of the Site to be capped (generally these soils occur
in Wetlands A, B, and C).
Offsite disposal of all drums excavated from the Fill Area.
Dewatering of contaminated soil in Wetlands A, B, and C
prior to excavation, and treatment of the water in the
onsite water treatment system prior to discharge to North
Run Creek. The discharge of treated water will meet the
substantive requirements of a VPDES permit. Planting of
excavated wetlands with wetland vegetation as approved by
EPA. Mitigation of wetland loss due to capping with
10
-------
creation of wetlands of equal or better value, as approved
by EPA-.
(4) Containment
Construction of a RCRA Subtitle C cap over the Site where
the surface soil exceeds the Site-specific cleanup levels
stated above and as far into the wetlands as possible.
Construction of a slurry wall around the perimeter of the
cap. Construction of a dewatering system inside of
cap/slurry wall to produce an intragradient condition with
onsite treatment of ground water by carbon adsorption and,
if necessary, precipitation of metals; discharge of treated
ground water to North Run Creek;
(5) North Run Creek and Talley's Pond
Excavation and onsite disposal of sediments in the oxbow ofr
North Run Creek north of the Site.
Sampling of sediments in Talley's Pond and sediments
previously dredged by the owner of the Pond. Excavation,
treatment, and offsite disposal of the sediments in or
previously dredged from Talley's Pond which exceed the Site-
specific cleanup goals.
(6) Institutional Controls
Implement institutional controls to prohibit residential
development of the Site and use of ground water at the Site,
(7) Ground Water Monitoring
Long-term ground water monitoring (at least 30 years).
Performance Standards
The selected remedy addresses all of the contaminated media
at the Site. By instituting all of these components, the Site .
risks'will be reduced to witihin EPA's acceptable risk range. The
performance standards for the major components of the selected
11
-------
remedy include Che following:
(1) Existing Structures
To reduce the risk to human health and the environment via
the exposure pathways attributed to the existing structures
on the Site, the concrete drip pad, holding pond, shop,
office, and shed will be demolished, cleaned of any residual
soil, decontaminated, and disposed of in accordance with
Part VIII of the Virginia Solid Waste Management Regulations
(VSWMR) and as approved by EPA. Decontamination and
disposal must also meet the requirements of 40 C.F.R. Part
268. Waste water generated during the decontamination will
be collected, treated and discharged to North Run Creek.
The discharge of treated water will meet the substantive
requirements of a VPDES permit.
(2) Unlined Pond
To reduce the risk to human health and the environment via-
the exposure pathways attributed to the unlined pond,
surface water in the pond will be removed, treated, and
discharged to North Run Creek. Closure and post closure of
the unlined pond will be performed in accordance with the
VHWMR. The discharge of treated water from the unlined pond
will meet the substantive requirements of a VPDES permit.
To reduce the risk to human health and the environment via
the exposure pathways attributed to the K001 waste,
approximately 70 cubic yards of K001 waste will be excavated
from the unlined pond and incinerated (the Best Demonstrated
Available Technology for K001 waste) at an offsite facility
approved by EPA and operating in accordance with, among
other things, 40 C.F.R. Part 264, Subpart 0. If the level
of dioxins/furans in the K001 waste exceeds the level which
the incinerator is permitted to accept, the K001 waste will
be dechlorinated onsite to bring the level of dioxins/furans
down to a level at or below that specified in the
incinerator's permit prior to shipment.
(3) Soil
To reduce the risk to human health and the environment via
12
-------
the exposure pathways attributed to the surface soil in
areas beyond the extent of the cap that exceed the cleanup
levels of 5.1 mg/kg carcinogenic PAHs, 48 mg/kg PCP, or 33
mg/kg arsenic, approximately 7,200 cubic yards of soil will
be moved to the area to be capped prior to construction of
the cap. Excavated wetlands will be restored to the
appropriate contours and revegetated with a diverse
community of indigenous species as approved by EPA.
(4) Containment
To reduce the risk to human health and the environment via
the exposure pathways attributed to the surface soil at the
Site, a cap will be constructed over a portion of the Site
which meets the requirements of RCRA Subtitle C, and
regulations promulgated thereunder, particularly the closure
requirements at 40 C.F.R. Part 264, Subparc N. Because the
soils in areas with the highest levels of contamination
would remain under the cap, the design and construction of
any planned development of the Site must be incorporated
into the design and construction of the cap to prevent
exposure to these soils. The cap will be approximately 11.5
acres in size. The cap is not expected to cover all of the
contaminated portions of Wetlands A, B, and C. The loss of
wetlands through capping will be mitigated by the creation
of wetlands of equal or better value. All wetland
restoration and monitoring must be approved of by EPA.
:-- reduce the risk to human health and the environment via
. tha exposure pathways attributed to the migracion of ground
water from the Site, a slurry wall will be constructed
around the perimeter of the cap and a dewatering system will
be constructed within the slurry wall to create an
intragradient condition. The dewatering system will consist
of two vertical caissons constructed to the bedrock with
horizontal laterals installed on top of the hardpan and on
top of the bedrock. Construction techniques will be
implemented to prevent the migration of ground water or
DNAPLs along the caissons through the hardpan. The
horizontal laterals will be installed with clean washed
gravel or gravel packs. The ground water collected in the
horizontal laterals will be treated via carbon adsorption
and, if necessary, precipitation of metals, pr.i.r to
13
-------
discharge to North Run Creek. The ground water will be
treated to comply with the substantive requirements of a
VPDES permit'for discharge to North Run Creelc. The carbon
from the carbon adsorption will be regenerated at an offsite
facility approved by EPA. All sludges generated will be
disposed of at an offsite facility approved by EPA.
(5) North Run Creek and Talley's Pond
To reduce the risk to human health and the environment via
the exposure pathways attributed to sediments in the oxbow
of North Run Creek north of the Site> sediments exceeding
the cleanup levels of 5.1 mg/kg carcinogenic PAHs, 48 mg/kg
PCP, and/or 33 mg/kg arsenic will be moved to the area of
the Site to. be capped.
To ascertain that the remedy is protective of human health
and the environment, the sediments in Talley's Pond and the
sediments that were previously dredged by the owner of
Talley's Pond will be sampled to determine whether they
exceed any cleanup levels for the Site. If the sediments
exceed a cleanup level (s), the sediments will be excavated,,
treated, and disposed of at an offsite facility approved of
by EPA.
(6) Institutional Controls
To restrict access to the soil at the Site, institutional
controls prohibiting residential development at the Site
will be implemented.
. To restrict access to the contaminated ground water under
the Site, institutional controls prohibiting use of the
ground water will- be implemented.
(7) Ground Water Monitoring
To determine if MCLs are being met at the boundary of the
Site, long-term ground water monitoring will be performed
for.at least thirty years. The ground water"monitoring will'
include sampling for arsenic, chromium, copper, zinc, PAHs,
and PCP. The appropriate number and location of the
14
-------
monitoring wells will be determined during the design phase.
EPA may modify or refine the selected remedy during the
remedial design and construction. Such modifications or
refinements, if any, would generally reflect results of the
engineering design process.
H. DOCUMENTATION OF SIGNIFICANT CHANGES
The Proposed Plan, which identified the revised cleanup plan
as EPA's preferred alternative for the Site, was released for
public comment on May 4, 1996. EPA has reviewed the verbal
comments expressed at the May 14, 1996 public meeting (no written
comments were submitted to EPA during the 30-day public comment
period which ended June 4, 1996) and determined that no
significant change to the remedy identified in the Proposed Plan
is necessary.
15
-------
RENTOKIL, INC. SITE
HENRICO COUNTY, VIRGINIA
RESPONSIVENESS SUMMARY
August 1996
This Responsiveness Summary documents public concerns and
comments expressed during the public comment period. The Summary
also provides EPA's responses to those comments. The information
is organized as follows:
Overview
Summary of Comments and Questions Expressed During Public
Meeting and EPA Responses
I. Overview
The 30-day public comment period for the amended remedy for.-
the Rentolcil, Inc. Site began on May 4, 1996 and ended on June 4,
1996. To facilitate commenting, EPA'held a public meeting at the
Board of Supervisors Board Room at the Henrico County Government
Complex.on May 14, 1996.
At the meeting, EPA discussed the ground water modeling
performed for the Site as part of the Value Engineering analysis
during the design phase. EPA also presented the Proposed Plan
for deleting treatment of "hot spots" at the Site. EPA explained
that the ground water modeling indicated that the "hot spots"
treatment had virtually no impact on the ground water
contamination at the Site. EPA also explained that the remainder
of the previously selected.remedy would be implemented as
originally planned, including:
demolition of existing structures on the Site;
removal of the unlined pond;
drum disposal;
soil consolidation prior to capping;
construction of multilayer cap, slurry wall, and
dewatering system;
-------
sediment excavation and disposal;
institutional controls; and
-long-term ground water monitoring.
The May 14, 1996 public meeting also provided the
opportunity for the public to ask questions and express opinions
and concerns. During the meeting, residents expressed concerns
on the limits of sampling down stream of the Site, the depth-and
width of the slurry wall, the possibility of re-use of the Site,
the capping of wells where public water was installed, the length
of monitoring the ground water at the Site, and who is
responsible to pay for the cleanup of the Site.
The comments and questions expressed during that meeting and
EPA's responses to those comments and questions are described in
the following summary-
II. Summary of Comments and Questions Expressed During Public
Meeting and EPA's Responses
Questions presented at the May 14, 1996 public meeting are
summarized briefly in this section and are grouped according to
subject. The EPA response follows each question presented.
1. A resident asked if the sediments in the wetland on the
other side of Ackley Avenue and down stream of the wetland were
sampled for contamination from the Site.
EPA Response: The wetland on the other side of Ackley Avenue and
the down stream areas were not sampled for the reason indicated
below. As shown on Figure-1, Wetland C is located at the
southwest corner of Ackley Avenue and Peyton Street, across
Peyton Street from Wetland B. The wetland the resident refers to
is at the southeast corner of Ackley Avenue and Peyton Street,
across from Wetland C. Wetlands B and C are connected by two 18"
culverts under Peyton Street. Surface runoff discharges from the
Site through a ditch to Wetland B, where it is retained and
discharges to Wetland C when flow is high. Ditches have been
artificially cut into Wetland C approximately 60 feet south of
the outlet of each culvert. A ditch parallel to the south side
of Peyton Street carries runoff from Wetland C to the east and
-------
EXPLANATION: ,
— «• »ImrrmiiMni SliMm
—"—— Contour lm*v«l
——AMM oalMMM LoccK
COAMM*)
NOTfcS:
I. Co.t|guf Intofvri «wo IMI.
NW«NM« (Ml.
200 FMI
KALE
FIGURE 1
lRFArpA^ ROWING PRIMARY
SURFACE WATER DRAINAGE AREAS
-------
ultimately to a 24" culvert under Ackley Avenue. Because the
invert of the 24" culvert is about 2 feet above the flow line of
the south ditch arid the normal elevation of Wetland C, Site-
related runoff waters are retained within Wetland C.
2. A resident asked if the slurry wall proposed to be
constructed at the perimeter of the Site would be 25-foot deep.
EPA Response! The slurry wall will be keyed into the granite
bedrock, which varies between 25 to 30 feet deep.
3. A resident asked how do we know that contamination will not
escape through the slurry wall.
EPA Response: B:i3ed on actual treatability testing of the Site
soil with differ^t types of bentonite, permeabilities in the 10"
7 to 10"8 cm/sec vange can be achieved. Also, once the area
within the slurry wall and cap is drained, an inward gradient of
ground, water will be created. At that time, the level of ground?
water in .the area outside the slurry wall will be higher than the
•level within the slurry wall. As such, any flow of ground water"
through the. slurry wall would be into the slurry wall/cap area
rather than to the outlying aquifer.
4. A resident asked what happens to the soil that is excavated
to install the slurry wall.
EPA Response: Most of the excavated soil from the slurry wall
trench will be used to form the slurry wall. The slurry wall mix
contains only 1% bentonite. If there are any soils remaining
after construction of the slurry wall, they will also be
consolidated onto the surface of the Site prior to construction
of the cap.
5. A resident asked how long will the site remain contaminated.
EPA Responger It is conceivable that the organic contamination
(i.e., pentachlorophenol as well as the PAHs associated with
creosote), will biodegrade over time. In addition, some
scientists theorize that DNAPLs move more freely when they are
taken out of the water phase, such as what will occur when the
dewatering system Bowers the ground water level within the area
of the slurry wai, and cap". If the DNAPLs do move more freely, a
-------
substantial amount of contamination will be collected in the
dewatering system. The inorganic contamination (i.e., arsenic,
copper, chromium,'and zinc associated with the CCA and CZA
treatment solutions) might never be removed since they do not
biodegrade and they tend to strongly adhere to soil particles.
Although the purpose of this ROD Amendment is to delete treatment
of the "hot spots", EPA believes the Site would remain
contaminated for just as long as under the original ROD since the
original ROD also did not include treatment of all of the soils
at the Site.
6. A resident asked if it will be safe to allow people to work
at the Site after remediation is completed.
EPA Response: It will be safe for people to work at the Site
after the cap is constructed since the cap will prevent direct
exposure to the Site contaminants.
7. A resident asked whether the $10,500,000 difference between'
the cost of the original cleanup plan and the cost of this
'revised cleanup plan is due entirely to the excavation and
treatment of the "hot spots."
EPA Response: Most of the cost difference is associated with
excavation, sampling, and staging the "hot spot" soil requiring
treatment. At the time of the original ROD, the amount of soil
requiring treatment was estimated to be 5,150 cubic yards. Based
on more precise measurements during the design, that amount had
increased to 12,000 cubic yards. Another large portion of the
cost difference is the cost of treating surface water during
remediation. It should be noted that the cost of treating
surface water during remediation was not included in the original
cost estimate.
8. A resident asked whether their domestic wells should be
abandoned where public water was made available.
E;PA Responses. • Since the ground water contamination did not reach
these wells, there is no reason to abandon these wells. However,
the monitoring wells installed during the investigation of the
Site should be abandoned in accordance with Henrico County
requirements. .
-------
9. A resident asked how additions/modifications or new
construction is handled.
*
EPA Response,: Rentokil, Inc. is legally responsible to maintain
the integrity of the cap. Since contamination will remain at the
Site after remediation is complete, a review of the Site will be
performed at least every five years to determine if the remedy is
still protective of human health and the environment. This will
include a review of whether the cap is still being maintained.
10. A resident asked who will make sure the contamination is
still being contained at the Site.
EPA Response; As stated in the response to Number 9 above, a
review of the Site will be performed at least every five years to
assure that the remedial action remains protective of human
health and the environment, including whether the cap is being
maintained. An analysis of whether the ground water
contamination is being contained will be part of this review.
•
11. A resident asked why the long-term ground water monitoring
extends for only for 30 years.
EPA Response: The original ROD actually states that the long-
term ground water monitoring shall be performed for at least 30
years. .The period over which a remedial action requires
maintenance and/or operation (the period of performance) is an
important factor in present worth analyses. It is EPA policy
that the period of performance for remedial action alternatives
requiring perpetual care should not be costed beyond thirty
years. Therefore, the 30-year period is the timeframe EPA uses
in order to compare differing remedial alternatives to cleanup
Superfund sites.
As stated in the response to Number 9 above, a review of the Site
will be performed at least every five years to assure that the
remedial action remains protective of human health and the
environment. -In accordance with Paragraph IX of the Consent
Decree between EPA and Virginia Properties, Inc. (VPI), VPI shall
conduct any studies and investigations as requested by EPA in
order to permit EPA to conduct reviews at least every five years.
Further, the Consent Decree states that if the Regional
Administrator, EPA Region III, or his/her delegate determines
-------
that information received, in whole or in part, during the review
conducted indicates that the Remedial Action is not protective of
human health and tihe environment, VPI shall undertake any further
response actions EPA has determined are appropriate and that are
not barred by the Covenant Not to Sue. Should EPA determine that
the remedy selected for the Site is no longer protective of human
health and the environment, EPA shall direct VPI to perform
additional response actions.
12. A resident asked who is responsible for the Site
contaminants after the buildings have outlasted their longevity?
EPA Response: As a requirement of the Consent Decree, VPI shall
record a certified copy of the Consent Decree with the Recorder's
Office (or Register of Deeds or other appropriate office),
Henrico County, Virginia. Thereafter, each deed, title, or other
instrument of conveyance for property included in the Site shall
contain a notice stating that the property is subject to this
Consent Decree...and shall reference the recorded location of the
Consent Decree and any restrictions applicable to the property
under this Consent Decree. The obligations of VPI with respect ^
to the provision of access and the implementation of
institutional controls shall be binding upon VPI and any and all
persons who subsequently acquire such interest.
13. A resident asked whether the ground water contaminants would
move while the slurry wall is being constructed.
EPA Response: Contaminant movement has been slow to date and it
is unlikely that contaminants would move beyond their present
location because of construction of the slurry wall.
Construction of a slurry wall is a very dynamic operation. As
the trench is being excavated, the previously excavated soil is
being mixed with bentonite, tested, and then re-deposited back
into the trench. Testing of the mixture of soil and bentonite
must be done prior to re-depositing back into the trench to make
sure the mixture meets or exceeds the performance standards of
permeability^ As a precaution, ground water monitoring is
performed during the construction of the entire remedy to monitor
for accelerated movement of the ground .water plume.
14. A resident asked whether Henrico County taxpayers are paying
for the Site cleanup.
-------
EPA Response; Through the Consent Decree between EPA and VPI,
VPI agreed to pay all costs associated with the Site cleanup
including the construction costs, the engineering costs, and the
oversight costs incurred by EPA, their contractors, and VDEQ.
15. A resident made a comment that she supported the idea of re-
using the Site by constructing buildings on top of the cap which
could generate both jobs and tax revenues for Henrico County.
EPA Response: Comment noted.
------- |