United States
Environmental Protection
Agency
Off ice of
Emergency and
Remedial Response
EPA/ROD/R03-93/168
June 1993
PB94-963912
Superfund
Record of Decision:
Rentokil Virginia Wood
Preserving, VA
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R03-93/168
3. Recipient's Accession No.
Title and Subtitle
SUPERFUND RECORD OF DECISION
Rentokil Virginia Wood Preserving Division, VA
First Remedial Action - Final
S Report Dst»
06/22/93
7. Authors)
8. Performing Organization Rspt No.
8, Performing Organization Name and Address
10 Project Taskwork Unit No.
11. Contraet(C) or Gr»nt(G) No.
(G)
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report & Period Covered
800/800
14.
1& Supplementary Notes
PB94-963912
ia Abstract (UmH: 200 words)
The Rentokil Virginia Wood Preserving Division site is a former wood treating facility
located in Henrico County, Virginia. Land use in the area is mixed light industrial,
commercial, and low density residential. In addition, site features include woodlands,
wetland areas, a floodplain, Talley's Pond, and an unnamed tributary referred to as
North Run Creek. Residents living just north of the si-te use the municipal water
supply system to obtain their drinking water. From 1957 to 1990, onsite wood treatment
operations used products such as PCP, fuel oil, chromium zinc arsenate, copper
chromated arsenate (CCA), fire retardant, creosote, and xylenes. Wastes from the early
wood treatment operations reportedly were discharged to the blowdown sump, which is an
open earthen pit used for the discharge of waste processing fluids, located to the
north of the treatment cylinders. In 1963, the State required that the pit be cleared,
cleaned, and replaced with the concrete holding pond due to fish kills in Talley's
Pond. In 1976 or 1977, approximately 1,100 to 1,400 pounds of CCA, that was allowed to
precipitate in a process tank before it was rendered unusable, was disposed of in a pit
located along the north fence line of the site. When soil was excavated during the
removal of one of three production wells, a black substance, assumed to be creosote,
(See Attached Page)
17. Document Analysis a. Descriptors
Record of Decision - Rentokil Virginia Wood Preserving Division, VA
First Remedial Action - Final
Contaminated Media: soil, sediment, debris, sludge, gw, sw
Key Contaminants: VOCs (benzene, toluene, xylenes), other organics (dioxin, PAHs,
phenols), metals (arsenic, chromium)
b. Identifiers/Open-Ended Terms
c. COSATIFWoVGroup
ia Availability Statement
19. Security Class (This Report)
None
20. Security Class (This Page)
None
21. No. of Pages
102
22. Price
(SeeANS»-239.18)
£•• Instructions on Ktvtftu
OPTIONAL FORM 272(4-77)
(Formerly NTIS-35)
Department of Commerce
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EPA/ROD/R03-93/168
Rentokil Virginia Wood Preserving Division, VA
First Remedial Action - Final
Abstract (Continued)
was observed seeping into the wall of the excavation at a depth of approximately five
feet. In 1987, the contents of the covered holding lagoon were transported to offsite
treatment and disposal facilities. Because clean closure of the lagoon was not attempted,
and the cover was not replaced, the lagoon re-filled with water. As a result, a hazardous
K001 sludge, containing creosote and/or PCP, remains at the bottom of the lagoon due to
the treatment of wastewater from the wood preserving processes. Throughout site
operations, treated wood was stored in open areas onsite and was allowed to drip onto the
ground, contaminating the soil. In 1987, sampling during the RI indicated elevated levels
of arsenic, chromium, copper, and zinc in the sediment and surface water of North Run
Creek. In 1989, the owners of Talley's Pond dredged the sediment and sludge that had
accumulated at the bottom of the pond, placed them around the pond, and seeded the area.
In 1990, when onsite operations ceased, a cover was placed over the drip pad to shield it
from precipitation, and a roof was constructed over the concrete holding pond. In 1991,
all of the wood treatment equipment was removed offsite, and a layer of clean gravel was
placed over the entire surface of the site. In 1992, EPA required Rentokil to design and
construct sediment control structures to prevent additional migration of sediment
containing metals from the site into the North Run Creek, and to provide site security by
posting the area with warning signs and maintaining the existing fencing. In addition,
the CCA disposal areas were covered with heavy duty plastic sheeting anchored with a
gravel covering to minimize the continued migration of contaminated sediment. This ROD
addresses the contamination in several site areas, including the area of the former
blowdown sump, the drip pad, the unlined pond, the CCA Disposal Area, the Fill Area, the
perched and saprolite units, the three wetland areas, North Run Creek, and the remaining
structures onsite. The primary contaminants of concern affecting the soil, sediment,
debris, sludge, ground water, and surface water are VOCs, including benzene, toluene, and
xylenes; other organics, including dioxin, PAHs, and phenols; and metals, including
arsenic and chromium. .
The selected remedial action for this site includes demolishing, decontaminating, and
disposing of existing structures offsite; excavating and incinerating offsite
approximately 70 yd^ of K001 sediment and sludge, with prior onsite treatment using
dechlorination, if the level of dioxins/furans would cause a violation of the
incinerator's RCRA permit; extracting and treating surface water in the unlined pond
onsite using carbon adsorption, with onsite discharge of residuals to North Run Creek and
closure of the pond; dewatering, excavating, and consolidating approximately 7,200 yd^ of
surface soil from the three wetland areas to the area to be capped; treating the pond
water in an onsite water treatment system, prior to discharge to North Run Creek; re-
vegetating the excavated wetland areas; constructing a slurry wall, which includes a
dewatering system around the cap; treating contaminated ground water onsite using carbon
adsorption, with precipitation of metals, if necessary, with onsite discharge of the
treated water to North Run Creek; regenerating the spent carbon offsite, with offsite
disposal of sludge generated during the treatment process in an approved facility/-
excavating and treating onsite approximately 5,150 yd^ of the soil removed during
installation of the dewatering system and slurry wall, along with soil located in the CCA
Disposal Area and Fill Area, and the DNAPL-contaminated soil using low temperature thermal
desorption to remove PCP and carcinogenic PAHs; treating onsite the remaining soil which
exceeds the arsenic cleanup level using chemical fixation; disposing of and capping the
treated soil onsite, with disposal of any treated soil which does not meet the established
cleanup levels in an offsite RCRA facility; disposing of excavated drums from the Fill
Area offsite; excavating and disposing of sediment in North Run Creek onsite; excavating,
treating, and disposing of sediment in and around Talley's Pond offsite; providing for a
contingency remedy to treat onsite the K001 waste from the unlined pond using
dechlorination, if the level of dioxins/furans exceed the level which the incinerator is
permitted to accept; monitoring ground water; and implementing institutional controls,
including ground water and land use restrictions. The estimated present worth cost for
this remedial action is $10,907,000, which includes an estimated annual O&M cost of
$72,200 for 30 years. The estimated present worth cost for the contingency remedy is
$1,499,500.
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EPA/ROD/R03-93/168
Rentokil Virginia Wood Preserving Division, VA
First Remedial Action - Final
Abstract (Continued)
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific cleanup goals for the site are based on a human health risk of 10"^, and
include arsenic 33 mg/kg; PAHs 48 mg/kg; and PCP 48 mg/kg.
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RECORD OF DECISION
RENTOKIL/VIRGINIA WOOD PRB8ERVTNQ
DECLARATION
SITE NAME AMD LOCATION
Rentokil/Virginia Wood Preserving
Richmond, Virginia
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for
the Rentokil/Virginia Wood Preserving Site (the Site) in
Richmond, Virginia which was chosen in accordance with the
requirements of the Comprehensive Environmental Response,
Compensation and Liability Act of 1980 (CERCIA), as amended by
the Superfund Amendments and Reauthorization Act of 1986 (SARA),
and, to the extent practicable, the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP). This decision
document explains the factual and legal basis for selecting the
remedy for this Site. Information supporting the remedial action
decision is contained in the Administrative Record for the Site.
The Virginia Department of Environmental Quality concurs with the
selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from the
Site, if not addressed by implementing the response action
selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to public health, welfare,
or the environment.
DESCRIPTION OF TEE REMEDY
This remedy will address all of the media impacted by the
contamination at the Site. It is not warranted at this time to
divide the Site into smaller components called operable units to
address individual media. Based on the information derived
through the Remedial Investigation, the CCA Disposal Area, Fill
Area, and the dense nonagueous phase liquids (DNAPLs) pose
principal threats to human health. Since wastes will be left in
place, long-term monitoring of the ground water must be
performed.
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The selected remedy includes the following major components:
• Demolition, decontamination, and offsite disposal of the
existing structures.
• Excavation, dechlorination treatment (if necessary), and
offsite incineration of K001 waste from the unlined pond.
Removal and onsite carbon adsorption treatment of surface
water in the unlined pond.
• Construction of a RCRA Subtitle C cap.
• Excavation and onsite disposal of surface soil beyond
extent of cap.
• Excavation, low temperature thermal desorption (LTTD) and
fixation treatment, and onsite disposal of CCA Disposal
Area, Fill Area, and the DNAPL soil within 25 feet of
concrete drip pad, unlined pond, and former blowdown sump.
• Offsite disposal of drums excavated from the Fill Area.
• Construction of a slurry wall.
• Construction of a dewatering system within the cap/slurry
wall; onsite carbon adsorption treatment of ground water.
• Excavation and onsite disposal of sediments in the oxbow
of North Run Creek. Sampling of sediments in Talley's
Pond and those sediments previously dredged by the owner
with excavation, treatment, and offsite disposal if
sediments exceed cleanup levels.
• Institutional controls to prohibit residential development
of Site and use of the ground water at the Site.
• Long-term 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 a remedy that employs
treatments that reduce toxicity, mobility, or volume as their
principal element.
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Because this remedy will result in hazardous substances remaining
onsite above health-based levels, a review will be conducted (no
less often than every) five years after initiation of remedial
action to ensure that human health and the environment are being
protected by the selected remedy.
Stanley L. Laskowski
Acting Regional Administrator
Region III
Date
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DECISION SUMMARY for the RECORD OF DECISION
RENTOKIL, INC.
A. Site Name. Location, and Description
The Rentokil 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 as shown at Figure 2 (Site Location Hap).
The Site and surrounding land are presently zoned for light and
general industry.
As shown at Figure 3, there are three wetland areas which
receive runoff from the Site: the area immediately north of the
Site which is within the flood plain of an unnamed tributary to
North Run (Area A); the area at the southeastern corner of the
Site (Area B); and the area immediately south of the Site which
is across Peyton Street (Area C). The unnamed tributary north of
the Site is referred to as North Run Creek. Wetlands B and C are
presently connected by two 18" culverts under Peyton Avenue.
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. A ditch along the north side of Peyton Avenue also
collects runoff from the Site. This runoff flows through the
west culvert to Wetland C.
Ditches have been artificially cut into Wetland C
approximately 60 feet south of the outlet of each culvert. This
was done in association with the reconstruction of Peyton Street.
A ditch parallel to the south side of Peyton Avenue carries
runoff from Wetland C to the east and 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 and the
normal elevation of Wetland C, Site-related runoff waters are
retained within Wetland C.
The Site is comprised of the land occupied by the Rentokil
(Virginia Wood Preserving) facility as well as those portions of
land contiguous to the northcentral boundary and the southeastern
corner of the facility (Figure 4). The center of the Site is
highest in elevation. The surface runoff from the southern
portion of the Site flows toward Wetland B while the surface
runoff from the northern portion of the Site flows toward North
Run Creek, an intermittent stream. North Run Creek flows into
Talley's Pond approximately one mile southeast of the Site and
then flows approximately 0.7 miles more to North Run. North Run
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FIGURE 1
REGIONAL LOCATION MAP
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.1.-J*. Af- ^ ffc^ VpM.1
•AM MAT tOUftCI: IN* OM*: V*NoN
Twwn. Va.. 1MI: OlM ANM, V*. IMt.
FIGURE 2
SITE LOCATION MAP
VIRGINIA WOOD PRESERVE
«i iwn iw«r
PRESERVING SITE
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EXPLANATION: ,
— - - InttnnllMnl Strewn
1 ' -1 Coiftour Inttivll
———AppfonlnMt* Location
Contour InlMvri
NOTt-S:
I. Contour InMivd two (Ml.
2. EI«»»lH»n In IMI Aovt
mtm MW tovtl.
700 Fe«l
S-;ALE
FIGURE 3
TOPOGRAPHIC MAP SHOWING PRIMARY
SURFACE WATER DRAINAGE AREAS
VIRGINIA WOOD PRESERVING SITE
-------
0 100 200 Fot
SCALE
FIGURE 4
EXISTING STRUCTURES MAP
VIRGINIA WOOD PRESERVING PROPERTY, FACILITY, AND SITE
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flows approximately 2.7 miles downstream to Upham Creek, which in
turn flows into the Chickahominy River after approximately
another 2.5 miles.
The geology at the Site consists of the following features:
a top layer of sediments, a hardpan, a layer of saprolite, and
bedrock as shown on the representative cross-section at Figure 5.
The surface sediments consist of clayey silts and fine sands from
0 to 7 feet thick. The hardpan consists of silty to sandy clay
which varies from l to 10 feet thick in the vicinity of the Site.
The hardpan is 3 to 5 feet thick in the center of the Site, and
thins to less than 1 foot between the northern property boundary
and North Run Creek. The saprolite layer underlying the hardpan
consists of disintegrated granite residuum from 4.5 to 15 feet
thick in the vicinity of the Site. The bedrock is granite with
limited fracturing.
The Henrico County Health Department reported that there are
92 home wells within a 1-kilometer radius of the Site. Depths of
these wells reportedly range from 10 to 215 feet, with 20 to 40
foot deep wells being the most prevalent. Residents of Wakefield
Road, Mayfair Avenue, and Oakview Avenue, to the north of the
Site, are served by the municipal water supply system.
B. Site History and Enforcement Activities
Wood treatment operations at the Site were initiated in 1957
and continued until January 1990. The methods and the chemicals
used at the Site have changed over the years. Products used at
the Site include pentachlorophenol (PCP) in a solution with
either mineral spirits or No. 2 fuel oil, chromium zinc arsenate
(CZA), copper chromated arsenate (CCA), fire retardant (FR),
creosote, and xylene (Figure 6). The fire retardant is believed
to have been a water-based solution of ammonium phosphate or
ammonium sulfate. The fire retardant solution may also have
contained ammonium thiocyanate as a corrosion-inhibiting
additive.
Over the years, all of the wood treating facilities
installed on the Site have been taken out of service and most
have been removed. Figure 7 shows the original buildings and
equipment as well as the additions between 1963 and 1980.
Wastes from the early wood treatment operations were
reportedly discharged to the blowdown sump north of the treatment
cylinders. The blowdown sump was an open earthen pit used for
the discharge of waste processing fluids from 1957 to 1963. In
1963, under the direction of the Virginia State Water Control
Board, the pit was cleared, cleaned, and replaced with the
concrete holding pond. The Virginia State Water Control Board
requested these changes because of fish kills in Talley's Pond on
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sw
B
SITE
220-1
ui
ui
UI
CO
1
UI
8
<
fc
UI
O
3
ui
210-
200-
190-
180-
NE
B1
170-J
SCALE
VERTICAL SCALE IS 22X HORIZONTAL
WATER LEVELS FROM MEASUREMENTS OF JULY 1091
—— PERCHED WATER LEVEL
SAPROLITE WATER LEVEL
FIGURE 5
GENERALIZED CROSS SECTION FROM SOUTHWEST TO NORTHEAST
ACROSS THE VIRGINIA WOOD PRESERVING SITE
Moor*
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Date
^MMMBM-
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
197S
1979
19SO
1981
19S2
19S3
1984
19S5
1986
19S7
1988
1989
Pentachlorophenol
U7R, Mir.. n Fuel
Spirits OIL
Inorganics
Creosote
CZA CCA FR
Xylene
(Vapor
Drying)
(B)
•
(C)
Date
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
196S
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1085
1986
1987
1988
19S9
\O
oi.
KEY:
(B) = CCA Type B:
(C) =-CCA Type C:
(Z) = Boliden Salts:
- CuO
••••••••••
19.6
18.5
ZnO
•••••••i
9.4
35.3
47.5
CrO3
•MMMHM
7.5
AS205
~^HIM^M^BH~
45.1
34.0
40.7
Source: Summary of Operational History of Virginia Wood Facility
Preserving Facility September 1989.
FIGURE 6
Products Reportedly Used at Virginia Wood Preserving Facility
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EXPLANATION:
CD Additions In 1963/4
O C£J Addllkxn In 1969/71
d Additions hi 1979/80
F"l No Jonpr prating wd
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January 2, 1962 and on two previous occasions. Both the blowdown
sump and the concrete holding 'pond were linked to the covered
holding lagoon by an underground drain pipe. In 1974, the
underground drain pipe was closed and abandoned in-place because
a new water treatment/preservative recovery system was installed
which continuously recycled the wastewater.
In 1976 or 1977, a batch of CCA precipitated in a process
tank before it was used and was rendered unusable. The
precipitation was reportedly caused by a reduction of the
chromium from the hexavalent state to the trivalent state. This
batch of approximately 1,100 to 1,400 pounds of CCA was disposed
of in a pit (with alternating 6-inch layers of lime) located
along the north fence line in the northeast quadrant of the Site.
An area on the southeastern corner of the wood treating
facility property, next to Wetland B, was at one time filled with
materials from the Site. Some of the materials placed in this
area include wood scraps (some of which may have been treated)
and metal bands. In addition, crushed, heavily weathered drums
were observed during soil boring in the area.
Three production wells and five monitoring wells were
previously constructed on the Site but were not double-cased
through the hardpan layer. These wells were abandoned to prevent
continued potential cross-contamination between the perched
ground water unit and the saprolite ground water unit. The
production wells consisted of two steel-cased wells (one 4-inch
well and one 6-inch well) installed into the bedrock and one 36-
inch cement-lined well. The soil excavated during removal of the
36-inch well had a noticeable creosote odor. Also, a black
substance (assumed to be creosote) was observed seeping into the
wall of the excavation at a depth of approximately 5 feet.
In 1987, the contents of the covered holding lagoon were
transported to offsite treatment/disposal facilities. No soil or
water samples were collected at that time. Clean closure of the
lagoon in accordance with the Virginia Hazardous Waste Management
Regulations (VHWMR) was not attempted and the cover was not
replaced, allowing the lagoon to fill up with water again. The
sludge currently at the bottom of the pond is considered to be a
listed hazardous waste under the Resource Conservation and
Recovery Act (RCRA) with the designation K001. See VHWMR
Appendix 3.1 and 40 C.F.R. S 261.32. K001 waste is defined as
the bottom sediment sludge from the treatment of wastewaters from
wood preserving processes utilizing creosote and/or PCP.
Throughout the operational history of the Site, treated wood
was stored in nearly all open areas on-Site. A concrete drip pad
directly adjacent to the treatment cylinders was not installed
until 1979/1980. Because of the contamination resulting from the
previous practice of allowing the treated wood to drip onto the
10
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ground, the soil at the Site contains F032, F034, and F035 RCRA
listed hazardous waste, as defined at 40 C.F.R. S 261.31. F032
waste is defined as drippage from wood treating operations
utilizing PCP. F034 waste is defined as drippage from wood
treating operations utilizing creosote. F035 waste is defined as
drippage from wood treating operations utilizing solutions
containing arsenic.
In 1989, the owners of Talley's pond dredged the sediments
which were acculumating at the bottom of the pond. The owners
placed the dredged sediments around the pond and seeded the area.
After ceasing wood treatment operations in 1990, a polyvinyl
chloride (PVC) cover was placed over the drip pad to shield it
from precipitation and a roof was constructed over the concrete
holding pond. In the spring of 1991, all of the wood treatment
equipment was removed from the Site. The above ground storage
tanks and treatment cylinders were dismantled and disposed of by
a hazardous waste contractor. A layer of clean compacted clay
was placed over the area where the cylinders were located. In
addition, a roof was built over the former tank farm area and a
layer of clean gravel was placed over the entire surface of the
Site.
EPA proposed that the Site be listed on the National
Priorities List (NPL) in January 1987. The Site was placed on
the NPL in March 1989. Rentokil, Inc. and EPA signed an
Administrative Order By Consent in December 1987 to conduct a
Remedial Investigation/Feasibility Study (RI/FS) to identify the
types, quantities and locations of contaminants and to develop
ways of addressing Site contamination. Field work for the first
phase of the RI was conducted from May to August 1989. The field
work for the second phase of the RI was conducted in June and
July 1991.
Sampling during the RI indicated elevated levels of arsenic,
chromium, copper, and zinc in the sediment and surface water of
North Run Creek. The sampling results indicated levels of
arsenic which exceeded the chronic fresh water quality criteria
for the protection of aquatic life and the Safe Drinking Water
Act Maximum Contaminant Level (MCL).
In March 1992, EPA and Virginia Properties, Inc. (a wholly
owned subsidiary of Rentokil, Inc.) entered into an
Administrative Order by Consent for Removal Action (Order). The
purpose of the Order was to design and construct sediment control
structures to prevent additional migration of sediment containing
arsenic, chromium, copper, and zinc from the Site into North Run
Creek. The Order also required Virginia Properties, Inc. to
provide Site security by posting the area with warning signs and
maintaining the existing fencing. The sediment control
structures consist of a berm and a sediment trap located between
11
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the fence line and North Run Creek. These structures were
completed by June 22, 1992. Also, the CCA disposal area was
covered with heavy duty plastic sheeting anchored with a gravel
covering to minimize the continued migration of contaminated
sediment.
C. Highlights of Community Participation
The RI/FS Report and the Proposed Plan for the Rentokil Site
were released to the public for comment on January 8, 1993 in
accordance with the requirements of Sections 113(k), 117(a), and
121(f) of the Comprehensive Environmental Response, Compensation
and Liability Act of 1980 (CERCLA), as amended, 42 U.S.C.
S 9613(k), 9617(a), and 9621(f). These documents were made
available to the public in the administrative record maintained
at the EPA Docket Room in Region 3 and at the Henrico County
Municipal Reference and Law Library in the County Government
Complex, Parham Road at Hungary Spring Road. The notice of
availability for these two documents was published in the
Richmond Times-Dispatch on January 8, 1993. A public comment
period on the documents was held from January 8, 1993 through
March 10, 1993.
In addition, a public meeting was held by EPA and the
Virginia Department of Waste Management on January 20, 1993 in
accordance with Section 117(a)(2) of CERCLA, 42 U.S.C. Section
9617(a) (2). At this meeting, representatives from EPA presented
the findings on the contamination problems at the Site and the
remedial alternatives under consideration. A response to the
comments received during the public comment period is included in
the Responsiveness Summary, which is part of this ROD. This
decision document presents the selected remedial action for the
Rentokil, Inc. Site in Henrico County, Virginia, chosen in
accordance with CERCLA, as amended by SARA and, to the extent
practicable, the National Contingency Plan. The decision for
this Site is based on the Administrative Record.
D. Scope and Role of Response Action
The selected remedy addresses the media impacted by the
contamination at the Site including: surface and subsurface soil,
dense non-aqueous phase liquids (DNAPLs) in the soil in the area
of the former blowdown sump, the drip pad, and the unlined pond,
the CCA Disposal Area, the Fill Area, the ground water in the
perched unit and the ground water in the saprolite unit, the
surface water in the unlined pond, the sediments in the unlined
pond, the sediments in the three wetland areas, the sediments in
North Run Creek, the sediments in and around Talley's pond, and
the remaining structures on the Site. The principal threats at
the Site include the DNAPL soil, CCA Disposal Area, Fill Area,
and the surface water and K001 waste in the unlined pond. EPA
12
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has determined that it is not warranted to split the Site
remediation into operable units to address individual media.
E. .summary of Site Characteristics
The RI field activities and analytical program were designed
to define the extent of contamination in the soil, sediments,
surface water, and ground water on and around the wood treatment
facility, identify migration pathways, and provide data to
support a feasibility study of potential remedial actions. The
following tasks were completed at the Site:
• Topographic mapping;
• Surface soil sampling;
• Subsurface soil boring and sampling;
• Ground water well installation and sampling;
• Aquifer testing;
• Surface water and sediment sampling from surface water
bodies and wetland areas; and
• Biota sampling in selected locations of surface water
bodies.
A summary of the results from the RI sampling program is provided
below.
Surface Soil
The primary inorganic contaminants detected in the Site
surface soil include arsenic, chromium, and copper.
Concentrations of arsenic were detected across most of the wood
treatment facility property as well as in the wetland areas
located to the north and southeast. Arsenic detections ranged
from 1 to 10,400 milligrams per kilogram (mg/kg) as shown at
Figure 8. Chromium detections ranged from 3.1 to 3,890 mg/kg.
Copper detections ranged from 3 to 2,880 mg/kg.
The primary organic contaminants detected at the Site
include PCP, PAHs, and dioxins/furans. concentrations of these
contaminants mimic the distribution of arsenic throughout the
surface of the wood treatment facility as well as in the wetland
areas located to the north and the southeast. PCP detections
ranged from below the detection limit to 540,000 micrograms per
kilogram (/tg/kg) as shown at Figure 9. Polynuclear Aromatic
Hydrocarbons (PAHs) are constitutents of creosote which are
contaminants of concern at the Site. Carcinogenic PAHs
13
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LEOiNO:
—'»- AMtNtt CONCENTRATION CONTOUNlMt/kil
KMMO Oft SAMPLE LOCATION WITH Mtf NIC
CONCENTRATION IN «*/V|
A BOTTOM SEDIMENT SAMPLE LOCATION
•a MCKOMOUNO
DM NELL KMINO
10 KMLKMINa
M BOTTOM SEOWINT
FIGUtB-* . .
ARSENIC CONCENTRATIONS (mn/kg)
IN SURFACE SOILS (0- 2 Feet) AND SEDIMENTS
VIRGINIA WOOD PRESERVING SITE
-------
UOCNO:
,i M». • KNTMNLOMmtNOtOONCtNTIIAnON
COMTOUH m»»»i M»*H •»•• »«• n
• MMINO OW (AMPtllOCAItON WITH
ff NTACHiOKOrHtNOt CONCENTHATKM^ktl
A DOnOMMDtMCNTIAMnilOCATION
M KN100MINO
H K>TTOMHINMENT
KM. GONCINTNATIONW
NA NOrANALVZEO
'FIGURE 9
PENTACHLOROPHENOL CONCENTRATIONS big/kg)
|N SURFACE SOILS (0-2 Feet) AND SEDIMENTS
VIRGINIA WOOD PRESERVING SITE
-------
detections ranged from below the detection limit to 454,900 Mg/kg
as shown at Figure 10. Dioxins and furans were detected at total
concentrations up to 2,978 Mg/kg and 1,077 Mg/kg, respectively.
Because of the existence of many different isomers of dioxins and
furans, EPA uses the Toxicity Equivalency Factor (TEF) to compare
the differing isomers to the most toxic isomers, 2,3,7,8
tetrachlorodibenzodioxin (TCDD) and tetrachlorodibenzofuran
(TCDF). The dioxin and furan detections ranged from 0.013 to
10.37 Mg/kg TEF.
No soil samples were taken beneath the concrete pads in the
wood treating area.
Subsurface Soil
Two areas of non-aqueous phase liquids (DNAPLs)/creosote or
PCP product have been approximated based on physical observations
during the Remedial Investigation (RI), the investigation prior
to the RI, and the abandonment of previous wells. These two
areas, as shown on Figure 11, are primarily related to the former
treatment area and the unlined pond. The existence of
DNAPLs/product has only been documented qualitatively and is
based on visual observation of oily smears on excavated well
casings, oily material on the flexidip (a piece of equipment used
to measure DNAPLs), stained soils, or product which bubbled to
the surface during excavation activities. Based on these
observations, the DNAPL/product appears limited to the soils
above the hardpan with the exception of the Saprolite soils in
monitoring well DM-15.
At the top of the hardpan layer, arsenic detections ranged
from below the detection limit to 345 mg/kg while chromium
detections ranged from 4 to 252 mg/kg. The highest detections of
organic contaminants at the top of the hardpan layer were
associated with three of the previously indicated source areas:
the treatment area, unlined pond, and the fill material. PCP
detections ranged from below the detection limit to 100,000
jig/kg. Carcinogenic PAHs detections ranged from below the
detection limit to 254,600 Mg/kg. Dioxin and furan detections
ranged from 0.001 to 0.194 Mg/kg TEF. Dense non-aqueous phase
liquids (DNAPLs) were observed in soil at the top of the hardpan
in the former treatment area and in the area of the unlined pond.
Below the hardpan layer, arsenic detections ranged from
below the detection limit to 13.3 mg/kg, while chromium
detections ranged from 1.5 to 18.6 mg/kg. PCP detections range
from below the detection limit to 20,000 Mg/kg in the saprolite
soil and from below the detection limit to 82,000 Mg/kg at the
top of the bedrock. Carcinogenic PAHs range from below the
detection limit to 8,110 Mg/kg in the saprolite soil and from
below detection limit to 62,830 M9/kg at the top of the bedrock.
The only known location of DNAPL beneath the hardpan layer is at
16
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LEQEND:
IOOV
/
•>
A
•O
DM
•t
aot
100 200 F««t
ass
SCALE
Citclnogwtlc PAH concentration
contour In ug/kg (dMh*d whir* Inferred)
Boring or Mmpta location with
total PAH concMttritlon (uo/kg)
Bottom Mdlmwit (wnpto locitlon
soil boring
Well boring
Bottom MdlmMit
Concwurnlon twtow dvnctlon limit
rFIGURE
CARCINOGENIC PAH CONCENTRATION (ug/kg)
IN SURFACE SOILS (0-2 FEET) AND SEDIMENTS
VIRGINIA WOOD PRESERVING SITE
D«n«> ft Moor*
-------
Ci^
LEGEND:
• Soil Boring or Well
Data from Dames & Moore well and boring logs
combined with previous Bennett and Williams data
TFIGURE 11
LOCATIONS OF
DNAPL OBSERVATIONS
VIRGINIA WOOD PRESERVING SITE
Dames A Moore
-------
monitoring well DM-15, which is adjacent to the area of the
former blowdown sump. Several inches of free product were
observed in this monitoring well.
Ground Water
The uppermost ground water unit is the perched ground water.
Immediately below the perched ground water is the hardpan; below
the hardpan is the saprolite ground water unit; below the
saprolite ground water unit is the bedrock. Since the hardpan is
not continuous in the general area of the Site, the perched
ground water and the saprolite ground water are considered as one
aquifer. The aquifer has the characteristics of a Class IIA
aquifer (currently used for drinking water within the
Classification Review Area) since it is used as a source of
drinking water.
The primary inorganic contaminants detected in the ground
water at the Site include arsenic, chromium, and zinc. In the
perched ground water unit, the arsenic detections ranged from
below the detection limit to 868 micrograms per liter (/*g/l),
chromium detections ranged from below the detection limit to 51.8
/ig/1, and zinc detections ranged from 23.5 to 537 M9/1- The
Maximum Contaminant Levels (MCLs) for arsenic and chromium are 50
Mg/1 and 100 /ig/1, respectively. As shown at Figure 12, the
overall distribution of dissolved arsenic in the perched ground
water unit indicates the presence of two plumes: one centered in
the treatment area, and the other centered over the fill material
and the unlined pond. The distribution of dissolved zinc does
not correspond to the arsenic plumes. Rather, the distribution
of dissolved zinc appears sporadic, with no definable plume
apparent.
The primary organic contaminants detected in the ground
water at the Site are PCP and PAHs. The PCP detections in the
perched ground water unit ranged from below the detection limit
to 790 Mg/1 and carcinogenic PAHs detections ranged from below
the detection limit to 2,348 j*g/l. The MCL for PCP is 1 pg/1.
The PAH with the most stringent MCL is benzo(a)anthracene at 0.1
Mg/1- As shown at Figure 13, the overall distribution of PCP is
a plume centered in the treatment area and a smaller plume
centered in the area of the unlined pond. As shown at Figure 14,
the overall distribution of total PAHs is a plume centered in the
area of the treatment area.
In the saprolite ground water unit, arsenic was detected in
five samples, at a maximum concentration of 5.6 ng/l and chromium
was detected in two samples, at a maximum concentration of 13.2
Mg/1.
The overall distribution of organic contaminants in the
saprolite ground water unit is very similar to that in the
19
-------
LEGEND:
DM-lftA pERCHEO QuouNDWATER MONITORING WELL
ft WITH ARSENIC CONCENTRATION ~ -
•^•50-. CONCENTRATION CONTOUR
NA NOT ANALYZED DUE TO INADEQUATE WELL VOLUME
BOL BELOW DETECTION LIMIT
FIGURE. 12.
DISSOLVED ARSENIC CONCENTRATION - (pg/L)
IN PERCHED GROUNDWATER
VIRGINIA WOOD PRESERVING SITE
-------
LEGEND:
niA MONITORING WELL IN THE PIRCHEO
AQUIFER WITH KNTACHLOROPHENOL
10 CONCENTRATION IN ««fl
—»«-- ft NTACHLOROfHENOL CONCENTRATION
CONTOUR lut/ll
•OL CONCENTRATION IELOW DETECTION LIMIT
NA NOT ANALYZED -
INSUFFICIENT VOLUME
•FXGURE 13
PENTACHLOROPHENOL CONCENTRATIONS (ug/l)
IN PERCHED GROUNDWATER
VIRGINIA WOOD PRESERVING SITE
-------
MONITORINO WELL IN PERCHED
WATER TABLE AQUIFER WITH .
TOTAL PAH CONCENTRATION INJJB/L
TOTAL PAH CONCENTRATION
CONTOUR
CONCENTRATION BE LOW DETECTION LIMIT
NOT ANALYZED - INSUFFICIENT VOLUME
TOTAL PAH CONCENTRATIONS (ug/l)
IN PERCHED GROUNDWATER
VIRGINIA WOOD PRESERVING SITE
-------
perched ground water unit. The principal plume is centered in
the treatment area, with a second smaller plume centered in the
area of the unlined pond. PCP detections ranged from below the
detection limit to 2,500 pg/1 and carcinogenic PAHs detections
ranged from below the detection limit to 172 Mg/1.
Surface Water and Sediment
Surface water and sediment samples were taken from a total
of 16 locations including the wetland areas, North Run Creek,
Talley's pond, and North Run. The results of sediment analysis
indicate that deposition of sediment containing Site-related
organic and inorganic contaminants is occurring in North Run
Creek, principally into the oxbow just north of the Site.
Arsenic detections in stream sediments ranged from 0.6 mg/kg in
the background sample to 322 mg/kg at SW-3, the sampling location
closest to the Site. Chromium detections in stream sediments
ranged from below the detection limit to 618 mg/kg. PCP
detections in stream sediments ranged from below the detection
limit to 7,600 Mg/kg while carcinogenic PAHs detections ranged
from below the detection limit to 4,850 fig/kg.
Regarding surface water, arsenic analyses ranged from 9.9 to
1,640 M9/1 in unfiltered surface water samples and from 7.4 to
633 M9/1 in filtered surface water samples, with the highest
values corresponding to Station SW-3. Arsenic was detected in
Talley's pond at 59.6 pg/1 in an unfiltered sample. Chromium
detections ranged from 5.6 to 66 M9/1 in unfiltered surface water
samples at the three locations closest to and downstream of the
Site.
As stated previously, a berm and sediment trap was
constructed on June 22, 1992 in response to the above results
from Phases 1 and 2 of the RI sampling events. Subsequently,
additional surface water and sediment analyses were performed on
December 10, 1992. Regarding surface water, arsenic analyses
ranged from 4.6 ng/I in the background location to 22.4 pq/1 at
SW-3, and chromium analyses ranged from below the detection limit
at SW-3 to 11.0 M9/1 in the background location. Arsenic was
detected in Talley's pond at 15.2 Mg/1-
F. ?\V!T>ro?TY of Site Risks
As part of the RI/FS process, a Baseline Risk Assessment was
prepared for the Site to characterize, in the absence of remedial
action (i.e., the "no action" alternative), the current and
potential threats to human health and the environment that may be
posed by contaminants migrating in ground water or surface water,
released to the air, leaching through the soil, remaining in the
soil, or bioaccumulating in the food chain at ,the Site. A
23
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glossary of the key risk terms from the Baseline Risk Assessment
used in the ROD is provided at the end of this Decision Summary.
Based on the Baseline Risk Assessment discussed below,
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.
Human Health Risks
Contaminants of concern
The initial step of the Baseline Risk Assessment was to
compile a list of key indicator contaminants, those which
represent the highest potential risk to human health. The
following contaminants of concern were judged to represent the
major potential health risks at the Site:
arsenic benzoic acid
chromium 2,4-dimethylphenol
copper 2-methylphenol
zinc 4-methylphenol
benzene pentachlorophenol
ethylbenzene phenol
styrene PAHs
toluene dioxins
xylenes furans
Of these contaminants, arsenic, chromium, benzene, styrene,
pentachlorophenol, some of the PAHs, dioxins, and furans are
known to cause cancer in humans and/or laboratory animals and
thus are classified as carcinogens.
EPA has classified arsenic as a Group A Human Carcinogen,
based on extensive evidence of human carcinogenicity through
inhalation and ingestion exposure. Regarding noncarcinogenic
effects, arsenic compounds have been shown to produce acute and
chronic toxic effects, including irreversible systemic damage at
high doses. EPA has also listed hexavalent chromium as a Group A
Human Carcinogen via inhalation only, based on positive animal
studies and positive epidemiclogical studies. Regarding
noncarcinogenic effects, hexavalent chromium is a respiratory
tract irritant following inhalation and occupational exposure to
chromium compounds by inhalation has resulted in changes in the
kidney and liver. EPA has classified copper as a Group D
Carcinogen—not classified. Regarding noncarcinogenic effects,
copper has toxic effects at high dose levels including
gastrointestinal disturbances, hemolytic anemia, and liver
damage.
24
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EPA has classified PCP as a Group B2 Probable Human
Carcinogen because there is sufficient evidence of
carcinogenicity in animals but insufficient data in humans.
There are a wide range of noncarcinogenic effects associated with
PCP, including hepatic toxicity, kidney toxicity, and central and
peripheral nervous system toxicity.
EPA has classified TCDD-dioxin as a Group B2 Probable Human
Carcinogen because there is sufficient evidence of
carcinogenicity in animals but insufficient data in humans.
There are four major noncarcinogenic effects associated with
exposure to TCDD: chloracne, the wasting syndrome, hepatoxicity,
and immunotoxicity.
Hyposure Assessment
The goal of the exposure assessment is to determine the type
and magnitude of human exposure to the contaminants present at,
and migrating from, the Site. The exposure assessment was
conducted to estimate the Site risks if remedial action is not
taken.
To determine if human and environmental exposure to the
contaminants of concern might occur in the absence of remedial
action, an exposure pathway analysis was performed. An exposure
pathway has four necessary elements: 1) a source and mechanism
of chemical release; 2) an environmental transport medium; 3) a
human or environmental exposure point; and 4) a feasible human
or environmental exposure route at the exposure point. The
potential for completion of exposure pathways at the Site is
described in the following sections.
Transport Pathways
For any particular site, there may be a variety of potential
exposure routes, with either simple or complex pathways. The
simple pathways are of primary significance at the Site. Such
simple exposure routes for humans generally include consumption
of ground water, bathing with ground water, inhalation of
volatile contaminants in ground water during showering,
consumption of surface water, bathing with or playing in surface
water, ingestion of soil, dermal exposure to soil, and inhalation
of fugitive dust emissions. The ingestion pathways are the most
important at the Site, based on Site constituents and contaminant
distribution. Complex exposure routes are significantly less
important at the Site than simple pathways because the primary
contaminants have not been shown to bioaccumulate. Furthermore,
sampling data indicate that only minimal offsite migration of
contaminants has occurred in any environmental media to date.
The transport pathways evaluated at the Site include ground
water, soils, sediments, and runoff water. Based on the results
25
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of the sampling performed as part of the RI, the five primary
areas of contamination associated with the Site are as follows:
• Surface soils throughout the Site;
• Sediments in the unlined pond;
• DNAPL soils;
• Ground water plumes centered around the treatment area and
the unlined pond; and
• Sediments in North Run Creek and Wetlands A, B, and C.
The contaminants of greatest concern with respect to
potential exposure are those in the surface soils which are
distributed throughout the Site. Currently, exposure to
sediments at the bottom of the unlined pond is unlikely.
However, if the property is developed, future residents could
potentially be exposed. The DNAPL soils, CCA Disposal Area, and
Fill Area are principal threats according to EPA guidance.
Exposure to ground water does not currently occur but must be
considered for future use according to EPA requirements.
Exposure to the sediments and surface water in the wetlands and
North Run Creek may potentially take place when children wade or
play in these areas. Also, continued flow of runoff may move the
sediments further downstream. It should be noted that sampling
downstream of the oxbow of North Run Creek indicates that the
levels of contamination in the sediments and surface water
decrease rapidly away from the Site.
Exposure Scenarios
The Baseline Risk Assessment developed for the Site
incorporates a hybrid of EPA methodologies from the Superfund
Health Evaluation Manual (EPA/540/1-86/060) and the Risk
Assessment Guidance for Superfund (EPA/540/1-89/002) included in
the Administrative Record File. As part of this assessment, the
exposure point concentrations, or estimates of the chemical
concentrations that will be contacted over time, were determined
by the arithematic mean of the detected constitutents selected
for evaluation rather than the upper 95th percentile upper
confidence limit required by the Risk Assessment Guidance for
Superfund. The future use scenario utilized for the Site is
light industrial. Three scenarios, encompassing the likeliest
potential exposure pathways, have been evaluated in the Baseline
Risk Assessment. They are:
• Scenario 1: Worker exposure to soil contaminants;
• Scenario 2: Exposure to surface water contaminants; and
26
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• Scenario 3: Hypothetical ground water usage exposure.
Scenario 1 addresses surface soil related exposures that
could occur to adult workers under the light industrial outdoor
exposure scenario. Since the soils are contaminated with metals
and relatively nonvolatile organic compounds, the worker exposure
scenario addresses exposure from ingestion and dermal adsorption
of contaminants in soil, and inhalation of soil contaminants
entrained in airborne particulates. The key variables in the
worker exposure scenario include a soil ingestion rate of 100
mg/day, an exposure frequency of 250 days/year, an exposure
duration of 30 years in a 70-year lifetime, an exposure time of 8
hours/day, and an inhalation rate of 2.1 nr/day.
Scenario 2 addresses surface water related exposures that
could occur if children were to periodically wade or play in
North Run Creek downstream of the Site. In this scenario, two
exposure pathways (ingestion and dermal adsorption of
contaminants in surface water) have been evaluated for children
aged 5 to 15. Key variables in the surface water exposure
scenario are an exposure time of 1 hour per day, an exposure
frequency of 100 days per year, an exposure duration of 10 years,
and an ingestion rate of 2 liters per year or 0.02 liters per
day.
Scenario 3 addresses potential ground water exposures that
could occur as a result of future use of ground water from the
Site. The exposure pathways evaluated are ingestion of ground
water and dermal absorption during showering. Key variables in
the ground water usage scenario are a water ingestion rate of 2.0
liters/day, an exposure frequency of 365 days/year, an exposure
duration of 30 years, and an exposure time while showering of
0.25 hours per day.
Exposure Point Concentrations
Data gathered during the RI are adequate to predict
potential exposure concentrations if the Site has reached steady-
state conditions (i.e., when the rate of transport of
contaminants is stable and in equilibrium with the environment).
In the absence of an established trend in historical data
indicating the contrary, the Site was considered to have reached
steady-state conditions.
Although the Risk Assessment Guidance for Superfund
indicates that the upper 95% confidence limit on the arithmetic
averages of contaminant concentrations are to be used to estimate
exposures, the arithmetic mean of the detected contaminants was
utilized because the Baseline Risk Assessment was initiated prior
to finalization of the guidance document. Also, even though
average concentrations were used in the Baseline Risk Assessment,
27
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rather than the more conservative levels dictated by EPA
guidance, an unacceptable risk was calculated for the Site.
The exposure point concentrations are those of the
contaminants in shallow soil, ground water and surface water.
Exposure from ingestion of ground water is calculated only to
characterize the potential risk from contaminants there. The
ground water itself is not used at the Site, but EPA guidance
requires that an assessment be performed based on the possibility
that the ground water could be used as a water supply in the
future. It appears that hydraulic communication has occurred
(and may still be occurring) at the Site between the perched
ground water unit and the saprolite ground water unit. In
addition, installation of the initial monitoring wells could have
contributed to the movement of contamination since they were not
double-cased through the intervening hardpan layer. Also, the
hardpan layer is absent in some areas of the Site and thins out
in the vicinity of North Run Creek.
Therefore, two exposure estimates were made for the future
use scenario, one for ground water from the perched ground water
unit and one for ground water from the saprolite ground water
unit. In addition, a third exposure for the use of the bedrock
ground water was performed in order to ascertain whether
contaminants from the Site had migrated there.
Toxicity Assessment
The purpose of the toxicity assessment is to compile
toxicity and carcinogenicity data for the chemicals of concern
and to provide an estimate of the relationship between the extent
of exposure to a contaminant and the likelihood and/or severity
of adverse effects. The toxicity assessment was performed in two
steps - hazard identification and dose-response relationship.
Hazard identification is a qualitative description of the
potential toxic properties of the chemicals of concern present at
the Site. The dose-response evaluation is a process that results
in a quantitative estimate or index of toxicity for each
contaminant at the Site. For carcinogens, the index is the
cancer potency factor and for non-carcinogens, it is the
Reference Dose.
Cancer potency factors (CPFs) have been developed by EPA's
Carcinogenic Assessment Group for estimating excess lifetime
cancer risks associated with exposure to potentially carcinogenic
chemicals. CPFs, which are expressed in units of (mg/kg-day)'1,
are multiplied by the estimated intake of a potential carcinogen,
in mg/kg-day, to provide an upper-bound estimate of the excess
lifetime cancer risk associated with exposure at that intake
level. The term "upper bound" reflects the conservative estimate
of the risks calculated from the CPF. Use of this approach makes
underestimation of the actual cancer risk highly unlikely.
28
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Cancer potency factors are derived from the results of human
epidemiological studies or chronic animal bioassays to which
animal-to-human extrapolation and uncertainty factors have been
applied.
Reference doses (RfDs) have been developed by EPA for
indicating the potential for adverse health effects from exposure
to chemicals exhibiting noncarcinogenic effects. RfDs, which are
expressed in units of mg/kg-day, are estimates of lifetime daily
exposure levels for humans, including sensitive individuals.
Estimated intakes of chemicals from environmental media (e.g.,
the amount of a chemical ingested from contaminated drinking
water) can be compared to the RfD. RfDs are derived from human
epidemiological studies or animal studies to which uncertainty
factors have been applied (e.g., to account for the use of animal
data to predict effects on humans). These uncertainty factors
help ensure that the RfDs will not underestimate the potential
for adverse noncarcinogenic effects to occur.
Risk Characterization
Excess lifetime cancer risks are determined by multiplying
the intake level with the cancer potency factor. These risks are
probabilities that are generally expressed in scientific notation
(e.g., lxlO~6 or 1E-6). An excess lifetime cancer risk of ixlCT6
indicates that, as a plausible upper bound, an individual has a
one in one million chance of developing cancer as a result of
site-related exposure to a carcinogen over a 70-year lifetime
under the specific exposure conditions at a site. EPA considers
excess lifetime cancer risks in the range of 10~4 to 10~6 to be
acceptable. Table 1 identifies Site media that exceed this
range.
In the absence of remedial action, the Site soils present a
total excess lifetime cancer risk of 4.7 x 10~3 for the average
case exposure from incidential ingestion, inhalation, and dermal
absorption. In other words, without remedial action,
approximately five additional people per one thousand have an
increased chance of developing cancer as a result of exposure to
the soil at the Site.
The excess lifetime cancer risk from oral and dermal
exposure to the average concentrations of contaminants in
perched ground water is 9.5 x 10"2. In other words, if no
remedial action is taken, approximately one additional person per
ten people has a chance of contracting cancer as a result of
exposure to the perched ground water. The majority of this risk
is due primarily to the ingestion of PAHs in the contaminated
perched ground water. The excess lifetime cancer risk determined
from ingestion and dermal absorption of average contaminant
concentrations in the saprolite ground water is 1.9 x 10~2. In
other words, if no remedial action is taken, approximately 2
29
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TABLE 1
Site Media Posing Unacceptable
Carcinogenic Risks
Media
Soil
Incidental Ingestion
Dermal Absorption
Perched Ground Water
Ingestion
Dermal Absorption
Saprolite Ground Water
Ingestion
Dermal Absorption
Carcinogenic Risk
6.5 x 10'4
4.0 x 10'3
Total: 4.7 x 10°
Total:
8.9 x 10'*
5.7 x 10'3
9.5 x 10'£
1.8 x 10
-Z
1.3 x 10
-3
Total:
1.9 X 10'
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additional people per hundred have a chance of contracting cancer
as a result of exposure to the saprolite ground water. The
majority of this risk is due primarily to the ingestion of PCP
and dioxins in the contaminated saprolite ground water.
Potential concern for non-carcinogenic effects of a single
contaminant in a single medium is expressed as the hazard
quotient (HQ) (or the ratio of the estimated intake derived from
the contaminant concentration in a given medium to the
contaminant's reference dose). The Hazard Index (HI) is
calculated by adding the HQs for all contaminants within a medium
or across all media to which a given population may reasonably be
exposed. The HI provides a reference point to gauge the
potential significance of multiple contaminant exposures within a
single medium or across media.
To determine the human health effects from the non-
carcinogenic contaminants, EPA uses the HI. Any media with a
cumulative HI equal to or greater than 1.0 is considered to pose
a potential risk to human health. The Site media which have an
HI equal to or greater than 1.0 are listed at Table 2.
With an HI of 4.5, arsenic, chromium, PCP and one of the
PAHs would pose a human health risk through the incidential
ingestion, inhalation, and dermal absorption of the Site soils.
With a total HI of 53.3, arsenic and one of the PAHs pose
human health risks through ingestion and dermal absorption of the
perched ground water. With a total HI of 37.9, one of the PAHs
also poses human health risks through ingestion and dermal
absorption of saprolite ground water.
The human health risks (both cancerous and noncancerous)
from exposure to perched and saprolite ground water provide a
reference point for evaluating future ground water risks; it does
not represent actual present day exposures since the ground water
contamination is confined to the area beneath the Site and no one
is utilizing the contaminated portions of either aquifer as a
source of domestic water. Although the perched and saprolite
ground water units have the characteristics of a Class IIA
aquifer, domestic use of the ground water from these units is not
likely to occur since a public water source is already available.
Significant Sources of Uncertainty
The general limitations inherent in the risk assessment
process as well as the uncertainty related to some of the major
assumptions in this assessment include:
1. The assumption that the contaminants at the Site have
reached steady-state conditions.
31
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TABLE 2
Site Media Posing Unacceptable
Hazard Indices
Media
Soil
Incidental Ingestion
Dermal Absorption
Inhalation
Perched Ground Water
Ingestion
Dermal Absorption
Saprolite Ground Water
Ingestion
Dermal Absorption
Hazard Index
1.7
1.4
1.4
Total: 4.5
47.3
6.0
Total: 53.3
29.3
8.6
Total:
37.9
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2. The uncertainties in the exposure assessment including
the current and future land uses and identification of
possible exposure pathways, parameter value uncertainty, and
determination of exposure point concentration.
3. The uncertainties in the toxicity values that are used
to estimate potential risk and toxic hazard.
Environmental Risks
An environmental assessment was performed to determine if
contaminants related to the Site are present in nearby surface
waters and sediments in available concentrations sufficient to
cause adverse ecological impacts. The contaminants evaluated
include: arsenic, chromium, copper, dioxins, furans, PAHs, PCP,
and zinc.
No State parks, cooperative public hunting areas,
unperturbed forest or critical habitats exist in the vicinity of
the Site. However, North Run Creek, Wetlands A, B and C, and
Talley's Pond are areas in which surface water and sediments show
evidence of Site-related contaminants. The results of the Phase
I RI surface water sampling and analysis indicate the presence of
inorganic contaminants within North Run Creek and within Wetlands
B and C. Concentrations of total (unfiltered) arsenic, copper,
iron, and zinc within the.wetland areas exceed chronic Federal
and Virginia ambient water quality criteria (AWQC) for freshwater
life. Within North Run Creek, the copper AWQC was slightly
exceeded at all stations (including the background station); the
arsenic AWQC was exceeded at the two stations located just
downstream from the Site; and the zinc AWQC (Virginia) was
exceeded at most locations (including the background station).
The Phase I data also demonstrate the presence of PCP in the
surface water collected from Wetlands B and C. These detections
were within the AWQC value of 13 Mg/1-
The Phase II RI data (North Run Creek only) indicate that
the arsenic AWQC (chronic and acute) was exceeded only at the
station just north of the Site (SW-3) and the copper AWQC was
exceeded at SW-3 and SW-5.
Although potential impacts from surface water to organisms
is indicated by comparison to AWQCs, the chronic and acute
aquatic toxicity testing conducted during the Phase II RI
indicates that there is no significant impact to aquatic
organisms in North Run Creek.
Regarding sediments, the Phase I RI data indicate that
arsenic concentrations are elevated at stations SE-3 (the same
station in North Run Creek where SW-3 was taken), SE-6 (Wetland
C), and SE-8 (Wetland B); chromium concentrations are elevated at
stations SE-6 and SE-8; and copper is elevated at station SE-8.
33
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PCP and PAHs were also detected in the sediments at stations SE-
3, SE-6, and SE-8. All of these stations are in areas of
deposition in either North Run Creek, Wetland B, or Wetland C
where accumulation of contaminants is expected to occur. The
Phase II RI data indicate that arsenic, chromium, and copper are
present at elevated concentrations in sediments of North Run
Creek at SE-3, and that arsenic concentrations are slightly
elevated at SE-13 (Talley's Pond).
Concentrations of inorganic and organic contaminants
detected in the wetland areas and inorganic contaminants detected
in North Run Creek indicate the potential for impact to
organisms. Observations made of the wetland areas directly
adjacent to the Site indicate the presence of stressed flora and
a general absence of fauna or signs of fauna. These areas
correspond to detections of elevated concentrations of site-
related contaminants, which have apparently contributed to the
degradation of flora and fauna. Observations of the Wetland A,
adjacent to North Run Creek, showed no signs of stress and signs
of fauna were generally abundant.
Actual or threatened releases of hazardous substances from
this Site, if not addressed by implementing the response action
selected in this ROD, may present ah imminent and substantial
endangerment to public health, welfare, or the environment.
G. Description of Alternatives
In accordance with the National Oil and Hazardous Substances
Contingency Plan (NCP), 40 C.F.R. Section 300.430(e)(9), remedial
response actions were identified and screened for effectiveness,
implementability, and cost during the FS to meet remedial action
objectives at the Site. The technologies that passed the
screening were assembled to form remedial alternatives. The
alternatives were then evaluated using the nine criteria required
by 40 C.F.R. Section 300.430(e)(9). The FS evaluated a variety
of technologies used in the development of alternatives for
addressing soil at the Site, ground water in both the perched and
the saprolite units, sediments in the unlined pond, sediments in
Wetlands A, B, and C, and the remaining structures on the Site.
The technologies and the approaches contained in the alternatives
listed below have been determined to be the most applicable for
this Site. The descriptions of Alternatives l through 5 reflect
the descriptions in the FS. Alternative 6 was developed after
receipt of the final FS. The capital costs, the Operation and
Maintenance (O&M) costs, present worth costs, and months to
implement for each of the alternatives listed below are estimates
based on present information.
34
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Common Elements
Ground Water Monitoring. All of the alternatives include a 5-
year review pursuant to Section 12l(c) of CERCLA and thirty years
of ground water monitoring. Ground water monitoring will be used
to evaluate the protectiveness of each remedial action because
contamination will be left in place. EPA will determine the
appropriate number and location of the monitoring wells during
the design phase. The monitoring will include, but not be
limited to, the requirements of Section 10.5.H of the Virginia
Hazardous Waste Management Regulations (VHWMR), VR 672-10-1. The
ground water monitoring will be performed for at least thirty
years, in accordance with the VHWMR. The monitoring will test
for arsenic, chromium, copper, zinc, PAHs, and PCP since these
were the primary contaminants detected in the ground water during
the RI sampling. •
Except for Alternative 1 ("No Action"), each remedial
alternative for the Site includes the following elements:
Institutional Controls. Institutional controls, including deed
restrictions and restrictions on the use of the ground water,
will be implemented. The deed restrictions will prohibit
residential development of the Site in order to prevent exposure
to contaminated soil. The deed restrictions are required since
none of the alternatives developed include complete remediation
of the contaminated Site soils. The restrictions on the use of
the ground water at the Site will prevent exposure to the
contaminated ground water.
Closure of Unlined Pond. Closure and post closure of the unlined
pond will be in accordance with Section 10.10.1 of the VHWMR,
surface impoundments closure and post closure requirements.
Since the K001 waste is a RCRA listed waste, it must be disposed
of in a Subtitle C facility. Because of the previous removal of
sediments from the unlined pond, it is not known at what level,
if any, dioxins may exist. If there are high concentrations of
dioxins/furans in the K001 waste, they will be chemically
dechlorinated onsite prior to offsite treatment and disposal.
Existing Structures, site remediation will require demolition
and removal of all existing structures on the Site, including the
concrete drip pad, holding pond, shop, office and shed. It is
anticipated at this time that only the concrete drip pad and
holding pond will require decontamination by high pressure steam
cleaning prior to disposal in an approved landfill.
Alternative is NO ACTION
Capital Cost: $ 000
Annual O&H Cost: $ 11,000
Present Worth: $169,000
35
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The NCP, 40 C.F.R. Part 300, which regulates Superfund
response actions, requires that a "no action" alternative be
evaluated at every NPL site in order to establish a baseline for
comparison. Under this alternative, EPA would take no further
action at the Site to prevent exposure to the contaminated media
or to reduce risks at the Site. Monitoring of the contaminated
ground water would be implemented.
Alternative 2: CAP WITH SLURRY WALL
Capital Cost: $ 9,740,000
Annual O&M Cost: $ 17,000
Present Worth: $10,001,000
Alternative 2 consists of the construction of an
approximately 11.5 acre RCRA Subtitle C capping system over the
Site and a slurry wall around the perimeter of the cap (Figure
15). The costs above reflect the installation of a rigid cap.
However, the capping system could be either rigid (such as
concrete or asphalt) or non-rigid (such as clay or membrane). In
either case, the cap would be designed to meet the landfill
closure requirements as provided at Part 10 of the VHWMR. Prior
to the construction of the cap, approximately 70 cubic yards of
KOOl waste would be excavated and treated in an offsite
incinerator. The KOOl waste would be chemically dechlorinated
onsite if the level of dioxins/furans present in the sediment
prevent treatment in an offsite incinerator. Approximately 7,200
cubic yards of soil located off of the wood treating facility
property containing concentrations of arsenic, PAHs, or PCP which
exceed the Site-specific cleanup levels would be excavated and
disposed of offsite. The Site-specific health based cleanup
levels developed for the Site are: 5.1 mg/kg for total
carcinogenic PAHs, 48 mg/kg for PCP, and 33 mg/kg for arsenic.
The time required to implement this alternative is estimated
at approximately 8 to 12 months.
Alternative 3: LOW TEMPERATURE THERMAL DE8ORPTZOH
Capital Cost: $18,176,000
Annual O&M Cost: $ 62,000
Present Worth: $19,129,000
Alternative 3 consists of: (1) excavation of approximately
22,700 cubic yards of surface soil (the top two feet) which
exceed the cleanup level for PAHs and PCP; (2) excavation of
approximately 8,600 cubic yards of subsurface soil contaminated
with DNAPLs; (3) onsite treatment of PCP and PAHs by Low
Temperature Thermal Desorption (LTTD), (4) fixation of the LTTD-
treated soils and the 13,700 cubic yards of surface soil which
exceed the cleanup level for arsenic; (5) onsite disposal of the
soil which meets the cleanup levels; and (6) passive
36
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PROPOSED CAPPING AREA
PROPOSED SLURRY WALL
Ft 15
-------
collection and onsite carbon adsorption treatment of contaminated
ground water. The Site-specific health based cleanup levels
developed for the Site are: 5.1 mg/kg for total carcinogenic
PAHs, 48 mg/kg for PCP. and 33 mg/kg for arsenic. These cleanup
levels equate to a 10~° risk to human health.
After demolition and removal of the existing structures,
gravels that have been spread over the contaminated soil will be
collected by screening and washed before excavating the
contaminated soil. The excavated soil would be transported to
the LTTD system located on the Site. Once in the LTTD unit, the
contaminated soil would be heated to 300 to 800° F, causing the
organics in the soil to volatilize into the air stream. The
organics vaporized in the LTTD system, including PCP and the
PAHs, would be removed with a carbon adsorption system. The
carbon would be regenerated at an offsite facility. The LTTD
system would contain air pollution control equipment enabling it
to meet federal and Virginia air emission requirements and
eliminating any unacceptable risks to human health or the
environment. Treatability studies of the LTTD system would have
to be performed during the remedial design phase to determine the
contaminant removal levels as well as to maximize the operating
parameters.
The LTTD-treated soil and remaining surface soil exceeding
the health-based cleanup level of 33 mg/kg of arsenic will be
treated by means of chemical fixation. The chemical fixation
process is a series of chemical reactions involving various
combinations of chemical reagents with a waste material to form a
chemically stable solid. Because a reagent would be added to the
soil during the fixation process, the volume of treated soil
would typically increase by an estimated 20 to 30 percent.
Treatability studies of the chemical fixation system would have
to be performed during the remedial design phase to determine the
contaminant removal levels as well as to maximize the operating
parameters.
The passive ground water collection system would consist of
approximately 3,000 feet of interceptor trench generally
constructed along the downgradient edge of the contaminated
ground water, in the former wood treating area, and in the area
of the unlined pond. The trench would be installed atop the
bedrock, which ranges in depth from 12 to 27 feet. Ground water
would be treated with a carbon adsorption system to meet the
discharge requirements for discharge to North Run Creek. The
carbon would be regenerated in an offsite facility.
Precipitation treatment may also be required to remove any
remaining metals from the ground water. If so, any sludges
produced in the treatment of the ground water would be disposed
of at an offsite facility. Treatability studies of the carbon
adsorption system would have to be performed during the remedial
design phase to determine the contaminant removal levels, whether
38
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metals precipitation is required and to maximize the operating
parameters. The 70 cubic yards of K001 waste will be excavated
from the unlined pond and treated in an offsite incinerator. The
KOOl waste would be chemically dechlorinated onsite if the level
of dioxins/furans present in the sediment prevent their disposal
in an offsite incinerator.
The costs for Alternative 3 stated above reflect backfilling
of the treated soil onsite and covering the backfilled soil with
six inches of clean soil. If, however, ARARs do not allow
backfilling of treated soil onsite, the soil would have to be
treated to meet the level for disposal in an offsite landfill.
The time required to implement this alternative is estimated
at approximately two years.
Alternative 4: INCINERATION
Capital Cost: $26,443,000
Annual O&M Cost: $ 62,000
Present Worth: $27,396,000
Alternative 4 consists of: (1) excavation of approximately
22,700 cubic yards of the top two feet of surface soil which
exceeds the cleanup level for PAHs and PCP; (2) excavation of
approximately 8,600 cubic yards of subsurface soil contaminated
with DNAPLs; (3) onsite treatment of PCP and PAHs by
incineration; (4) fixation of the incinerator ash and the 13,700
cubic yards of surface soil (top two feet) which exceed the
cleanup level for arsenic; and (5) passive collection and carbon
adsorption treatment of the contaminated ground water. The Site-
specific health based cleanup levels developed for the Site are:
5.1 mg/kg for total carcinogenic PAHs, 48 kg/kg for PCP, and 33
mg/kg for arsenic. These cleanup levels equate to a 10"6 risk to
human health.
After demolition and removal of the existing structures,
gravels that have been spread over the contaminated soil should
be collected by screening and washed before excavating the
contaminated soil. The excavated soil would be transported to
the incinerator located on the Site. The incinerator would be
required to achieve at least 99.99 percent destruction and
removal efficiency (ORE) for the organic contaminants in the soil
and to meet other pertinent RCRA incineration standards at 40
C.F.R. 264, Subpart O. The incinerator would include a stack, a
mechanical system to feed the contaminated materials into the
refractory-lined kiln, a secondary combustion chamber or
afterburner to maximize combustion efficiency, and an air
pollution control system such as a Venturi scrubber or a baghouse
filter to remove particulates (and acid gases, if present) from
the exhaust gases. A test burn would be required during the
39
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remedial design phase to confirm that the incinerator is capable
of meeting the ORE for the organic contaminants in the soil.
The incinerator ash and remaining surface soil exceeding the
health-based cleanup level of 33 mg/kg for arsenic would then be
treated by means of chemical fixation. The chemical fixation
process is a series of chemical reactions involving various
combinations of chemical reagents with a waste material to form a
chemically stable solid. Because a reagent would be added to the
soil during the fixation process, the volume of treated soil
would typically increase by an estimated 20 to 30 percent.
Treatability studies of the chemical fixation system would have
to be performed during the remedial design phase to determine the
contaminant removal levels as well as to maximize the operating
parameters.
The passive ground water collection system would consist of
approximately 3,000 feet of interceptor trench generally
constructed along the downgradient edge of the contaminated
ground water, in the former wood treating area, and in the area
of the unlined pond. The trench would be installed atop the
bedrock, which ranges in depth from 12 to 27 feet. Ground water
would be treated with a carbon adsorption system to meet the
discharge requirements for discharge to North Run Creek. The
carbon would be regenerated in an offsite facility.
Precipitation treatment may also be required to remove any
remaining metals from the ground water. If so, any sludges
produced in the treatment of the ground water would be disposed
of at an offsite facility. Treatability studies of the carbon
adsorption system would have to be performed during the remedial
design phase to determine the contaminant removal levels, whether
precipitation of metals is required and to maximize the operating
parameters.
The K001 waste would be excavated, chemically dechlorinated
onsite if high concentrations of dioxins/furans are detected, and
incinerated onsite. After incineration, the K001 waste would be
disposed of at an offsite facility.
The costs for Alternative 4 stated above reflect backfilling
of treated soil and incinerator ash onsite and covering with six
inches of clean soil. If, however, ARARs do not allow
backfilling of treated soil onsite, the soil would have to be
treated to meet the level for disposal in an offsite landfill.
The time required to implement this alternative is estimated
at approximately three years.
40
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Alternative 5: SOLVENT EXTRACTION
Capital Cost: $22,376,000
Annual O&M Cost: $ 62,000
Present Worth: $23,329,000
Alternative 5 consists of: (l) excavation of approximately
22,700 cubic yards of surface soil (top two feet) exceeding the
cleanup level for PAHs and PCP; (2) excavation of approximately
8,600 cubic yards of subsurface soil contaminated with DNAPLs;
(3) onsite removal of PCP and PAHs by solvent extraction; (4)
fixation of the solvent extracted-treated soil and the 13,700
cubic yards of surface soil (top two feet) exceeding the cleanup
level for arsenic; and (5) passive collection and onsite carbon
adsorption treatment of contaminated ground water. The Site-
specific health based cleanup levels developed for the Site are:
5.1 mg/kg for total carcinogenic PAHs, 48 kg/kg for PCP, and 33
mg/kg for arsenic. These cleanup levels equate to a 10~6 risk to
human health.
The oily residue generated from the solvent extraction
process will be treated by chemical dechlorination to remove the
expected high levels of dioxins/furans and then incinerated
offsite.
The passive ground water collection system would consist of
approximately 3,000 feet of interceptor trench constructed
generally along the downgradient edge of the contaminated ground
water, in the. former wood treating area, and in the area of the
unlined pond. The trench would be installed atop the bedrock,
which ranges in depth from 12 to 27 feet. Ground water would be
treated to meet the discharge requirements for discharge to North
Run Creek. Any sludges produced in the treatment of the ground
water would be disposed of at an off site facility.
The K001 waste would be excavated and treated in an offsite
incinerator. The K001 waste would be chemically dechlorinated
onsite if the level of dioxins/furans present in the sediment
prevents their treatment in an offsite incinerator.
The costs for Alternative 5 stated above reflect backfilling
of treated soil onsite beneath a six inch cover of clean soil.
If, however, ARARs do not allow backfilling of treated soil
onsite, the soil would have to be treated to meet the level for
disposal in an offsite landfill.
The time required to implement this alternative is estimated
at approximately two years.
41
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Alternative 6: OPFSITB DISPOSAL AMD CAP
Capital Cost: $21,563,000
Annual O&M Cost: $ 62,000
Present Worth: $22,616,000
Alternative 6 consists of: (l) excavation of approximately
22,700 cubic yards of surface soil (top two feet) exceeding the
cleanup level for PAHs and PCP; (2) excavation of approximately
8,600 cubic yards of subsurface soil contaminated with DNAPLs;
(3) offsite disposal of the excavated soil in an approved
landfill; (4) backfilling the excavated area with clean fill; (5)
construction of an approximately 11.5 acre two-foot thick soil
cover over the entire Site; and (6) collection and onsite carbon
adsorption treatment of contaminated ground water. The Site-
specific health based cleanup levels developed for the Site are:
5.1 mg/kg for total carcinogenic PAHs, 48 mg/kg for PCP, and 33
rag/kg for arsenic. These cleanup levels equate to a 10~6 risk to
human health.
The soil cover would consist of one foot of clean fill and
one foot of top soil. The surface of the soil cover would be
vegetated.
The ground water collection system would consist of
approximately 3,000 feet of interceptor trench constructed
generally along the downgradient edge of the contaminated ground
water, in the former wood treating area, and in the area of the
unlined pond. The trench would be installed atop the bedrock,
which ranges in depth from 12 to 27 feet. Ground water would be
treated to meet the discharge requirements for discharge to North
Run Creek. Any sludges produced in the treatment of the ground
water would be disposed of at an offsite facility.
The K001 waste would be excavated and treated in an offsite
incinerator. The K001 waste would be chemically dechlorinated
onsite if the level of dioxins/furans present in the sediment
prevent their treatment in an offsite incinerator.
The time required to implement this alternative is estimated
at approximately 12 months.
The costs developed for all of the above alternatives are
estimates. The annual Operation and Maintenance (O&M) costs
include the cost of annual sampling of four of the existing
monitoring wells for 30 years. The costs developed in the FS
include analysis of ground water samples for volatile organic
compounds (VOCs), semivolatile organic compounds (SVOCs), and
metals.
42
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H. gymTnar-y of Comparative Analysis of Alternatives
All of the six remedial action alternatives described above
were assessed in accordance with the nine evaluation criteria as
set forth in the NCP at 40 C.F.R. Section 300.430(e) (9) . These
nine criteria are categorized below into three groups: threshold
criteria, primary balancing criteria, and modifying criteria.
THRESHOLD CRITERIA
1. Overall protection of human health and the environment;
and
2. Compliance with applicable or relevant and appropriate
requirements (ARARs) .
PRIMARY BALANCING CRITERIA
3. Long-term effectiveness and permanence;
4. Reduction of toxicity, mobility, or volume through
treatment ;
5. Short-term effectiveness;
6. Implementability; and
7. Cost.
MODIFYING CRITERIA
8. State acceptance; and
9. Community acceptance.
These evaluation criteria relate directly to requirements in
Section 121 of CERCLA, 42 U.S.C. Section 9621, which 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. State and
community acceptance are modifying criteria formally taken into
account after public comment is received on the Proposed Plan. A
summary of the relative performance of the alternatives with
respect to each of the nine criteria follows. This summary
provides the basis for determining which alternative provides the
"best balance" of tradeoffs with respect to the nine evaluation
criteria.
1. overall Protection of HMTHflft Health and the Environment
A primary requirement of CERCLA is that the selected
remedial action be protective of human health and the
environment. A remedy is protective if it reduces current and
potential risks to acceptable levels within the established risk
range posed by each exposure pathway at the Site.
43
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Alternatives 3, 4, 5 and 6 are equally the most protective
of human health and the environment. These alternatives achieve
this protection by either treatment or removal of most of the
contamination at the Site and implementing institutional
controls. Alternative 2 provides adequate protection of human
health and the environment by controlling the risks posed by the
exposure pathways through construction of a capping system and
slurry wall and implementing institutional controls.
Alternatives 2-6 all include demolition, decontamination,
and offsite disposal of the existing structures, excavation,
treatment, and offsite disposal of the K001 waste, and closure of
the unlined pond. Alternatives 3, 4, and 5 also include
excavation and treatment of the top two feet of Site soils and
DNAPL soils as well as collection and treatment of the ground
water. Under Alternatives 3, 4, and 5 the soil would be treated
to health-based levels and disposed of onsite. Under Alternative
6, the excavated soil would be disposed of untreated in an
approved offsite landfill and replaced with two feet of clean
soil to prevent surface exposure to the remaining contaminants.
Under Alternatives 3, 4, 5, and 6 the ground water would be
treated to the substantive requirements equivalent to those of a
Virginia Pollution Discharge Elimination System (VPDES) permit
and the effluent discharged to North Run Creek. Treatment and
proper disposal of these contaminated media would further reduce
the risks at the Site associated with direct contact.
Alternative 1 accomplishes none of the above. Because
contaminant levels already exceed health-based levels,
Alternative 1 would not be protective of human health or the
environment. Since protection of human health and the
environment is a threshold criteria for any Superfund action,
this alternative cannot be selected and thus will not be
evaluated any further with regard to the other evaluation
criteria.
2. Compliance with ARARs
This criterion addresses whether a remedy will meet all of
the Applicable or Relevant and Appropriate Requirements (ARARs)
of other environmental statutes and/or provide grounds for
invoking a waiver under the NCP at 40 C.F.R. Section
300.430(f)(1)(ii)(C).
Under all of the alternatives, decontamination and disposal
of the existing structures would comply with state and federal
regulations, particularly Part VIII of the Virginia Solid Waste
Management Regulations (VSWNR) and those portions of 40 C.F.R.
Part 268 dealing with contaminated/inorganic solid debris.
Under all of the alternatives, the final treatment of K001
waste will be by incineration. Since no offsite incinerators are
44
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presently permitted to accept waste containing dioxins/furans,
the KOOl waste will be treated onsite using chemical
dechlorination if it contains dioxins/furans. Closure and post
closure of the unlined pond will be in accordance with Section
10.10.I of the VHWMR.
Alternatives 2 through 6 would meet all of the respective
ARARs of Federal and Virginia law (see Table 3). Although the
Site soils contain F032, F034, and F035 listed RCRA waste
(drippage from wood treatment processes which utilize PCP,
creosote, or arsenic solutions, respectively), Land Disposal
Restrictions (see 40 C.F.R. Part 268) have not been developed
yet. Therefore, Alternatives 3, 4, and 5 will comply with Land
Disposal Restrictions and Virginia disposal ARARs through
excavation, treatment to health-based levels, and onsite disposal
of the Site soils. Temporary storage and treatment of
contaminated media and/or debris must be in accordance with
VHWMR, Section 10.8, Use and Management of Containers, Section
10.9, Tanks, and Section 10.11, Waste Piles. Treatment standards
for media which fail the Toxicity Characteristic Leaching
Procedure (TCLP) for PCP are presently scheduled to be issued by
EPA by June 1993. Treatment standards for soil contaminated with
wood treating preservatives are presently scheduled to be issued
by EPA by March 1994. Offsite disposal of untreated soil under
Alternative 6 would have to be performed prior to implementation
of the treatment standards in order to avoid the prohibition on
land disposal. Dredging of sediments in North Run Creek or
Wetlands A, B, or C would be in compliance with the substantive
requirements of a Virginia Water Protection permit, VR 680-15-02.
Capping the soils in-place under Alternative 2 would not
trigger Land Disposal Restrictions. However, since the cap
cannot be extended all the way into the contaminated portions of
Wetlands A, B, or C and the soils in these areas contain RCRA
listed wastes (F032, F034, and F035), the contaminated soil in
these areas must be either disposed of in a RCRA Subtitle C
landfill prior to promulgation of a prohibition on land disposal
or treated in accordance with the treatment standards. Under
Alternative 6, all of the soil would have to be excavated and
disposed of in a RCRA Subtitle C landfill prior to the
prohibition on land disposal because none of the soil would be
treated under this alternative.
Work within the wetlands under Alternatives 2 through 6
would be in compliance with the Virginia Wetlands Act, Code of
Va. SS 62.1-13.1 - 13.2, and Virginia's Chesapeake Bay
Preservation Act, Code of Va. S 10.1-2100 et sea.. including the
Chesapeake Bay Preservation Area Designation and Management
Regulations (CBPA Regulations), VR 173-02-01.
The discharge of treated ground water and any process waters
to North Run Creek would have to comply with the substantive
45
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Standards,
Requirements,
Criteria, or
Limitations
Resource
Conservation and
Recovery Act
(RCRA)
Regulations
Clean Water Act
(CWA)
Regulations
CWA
Virginia Water
Quality
Standards
Citation
40 C.F.R. Part
268
40 C.F.R.
Section 122.44
40 C.F.R. Part
230, 33 C.F.R.
Parts 320,
323, and 330
Virginia
Regulation
(VR) 680-21-01
TABLE 3
ARARS
ACTION-SPECIFIC
Description
Land Disposal
Restrictions for
offsite disposal of
debris.
Ambient Water Quality
Standards for
discharge of ground
water treatment system
effluent to North Run
Creek.
Discharge of fill
material into
wetlands.
State Water Quality
Standards for surface
water serve as a
source for the
establishment of
discharge limits of
ground water treatment
system to North Run
Creek.
Applicable/
Relevant and
Appropriate
yes/no
yes/no
no/yes
yes/no
Discussion
Alternatives 2-6.
Alternatives 3, 4, 5,
and 6.
Alternatives 2-6.
Alternatives 3, 4, 5,
and 6.
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Virginia
Pollutant
Discharge
Elimination
System (VPDES)
Program
VR 680-14-01
TABLE 3
ARARs
ACTION-SPECIFIC
Effluent limitations
are established on a
case-by-case basis.
yes/no Alternatives 3, 4, 5,
and 6.
Virginia Toxics
Monitoring
Regulation
VR 680-14-2.5
Virginia Erosion
and Sediment
Control Law
Virginia
Hazardous Waste
Management
Regulations
(VHWMR)
VR 672-10-1
VHWMR
VHWMR
Toxics
Management
Regulation
Section 2
Virginia Code
Sections 10.1-
560 efr seq.
VHWMR Part 3
VHWMR Section
10.5.H
VHWMR Part 10
Requirements for
effluent discharge and
receiving stream
monitoring.
Methods to control
erosion and
sedimentation.
Hazardous Waste
determinat ion
requirements.
Ground water
monitoring
requirements.
Onsite stockpiling or
staging of soil and
other contaminated
material.
yes/no Alternatives 3, 4, 5,
and 6.
yes/no Alternatives 2-6.
yes/no Alternatives 3, 4, and
5. Since chromium
cleanup value not
established, treated
soil will undergo TCLP
to determine if RCRA
characteristic waste due
to chromium.
no/yes Alternatives 1-6.
yes/no Alternatives 3, 4, 5,
and 6.
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VHWMR
VHWMR Parts 3
and 10
VHWMR
VHWMR Part 7
TABLE 3
ARARs
ACTION-SPECIFIC
Treatment, storage,
and disposal of spent
carbon.
Transportation of K001
waste, treated soil
and sediments, and
spent carbon to an
offsite facility.
VHWMR
VHWMR Part 3
Treated soil and
sediments must meet
standards in order to
no longer be managed
as a hazardous waste.
yes/no Alternatives 3, 4, 5,
and 6 from ground water
treatment system.
Alternative 3 from LTTD
air emission treatment
system.
yes/no Alternatives 2-6 for
K001 waste and sediments
from North Run Creek
and, possibly, Talley's
Pond. Alternatives 3, 4,
and 5 for soil which
does not meet Site-
specific cleanup values.
Alternative 2 for soil
beyond extent of cap.
Alternative 6 for all
soil. Alternatives 3, 4,
5, and 6 for spent
carbon.
yes/no Alternatives 3, 4, and 5
for treated soil.
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TABLE 3
ARARs
ACTION-SPECIFIC
VHHMR
VHWMR Part 3
Hazardous Waste
determination
requirements.
yes/no
VHWMR
VHWMR
Virginia Solid
Waste Management
Regulations
(VSWMR)
VR 672-20-10
Virginia
Regulations for
Control and
Abatement of Air
Pollution
VHWMR Section
10.10.I
VHWMR Section
10.13.1
VSWMR Part 8
VR 120-01-01
Closure and post
closure requirements
for surface
Impoundments.
Surface impoundments
closure and post
closure requirements.
Treated soil and
sediments must meet
requirements prior to
disposal in a solid
waste landfill in
Virginia.
All air emissions from
Site activities must
meet air regulations.
yes/no
yes/no
yes/no
yes/no
Alternatives 3, 4, and
5. Since chromium
cleanup value not
established, treated
soil will undergo TCLP
to determine if RCRA
characteristic waste due
to chromium.
Alternatives 2-6.
Alternative 2.
Alternatives 3, 4, and 5
for soil which does not
meet Site-specific
cleanup values.
Alternative 2 for soil
beyond extent of cap.
Alternative 6 for all
soil.
Alternatives 2-6.
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Standards,
Requirements,
Criteria, or
Limitations
Safe Drinking
Water Act (SDWA)
Regulations
Virginia Hater
Quality
Standards
Citation
40 C.F.R.
Section 141.11
Virginia
Regulations
680-21-03.2
TABLE 3
ARAR8
CHEMICAL-SPECIFIC
Description
Maximum Contaminant
Level for discharge of
ground water treatment
system to North Run
Creek.
Site specific limits
for discharge of
treatment system
effluent to North Run
Creek.
Applicable/
Relevant and
Appropriate
yes/no
yes/no
Discussion
Alternatives 3, 4, 5,
and 6.
Alternatives 3,4, 5,
and 6.
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Standards,
Requirements,
Criteria, or
Limitations
Citation
TABLE 3
ARARs
LOCATION-SPECIFIC
Description
Applicable/
Relevant and
Approor iate
Discussion
Executive Order
11990 (Wetlands
Protection)
Virginia Hater
Protection
Permit
Chesapeake Bay
Preservation
Area Designation
and Management
Regulations
40 C.F.R. Part
6 (Appendix A)
VR 680-15-02
VR 173-02-01
Wetland protection and yes/no
restoration.
Regulates dredging, yes/no
filling, and
excavation activities
impacting wetlands.
Limitations on wetland yes/no
activities having an
impact on water
quality.
Alternatives 2-6.
Alternatives 2-6.
Alternatives 2-6.
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requirements equivalent to those of a VPDES permit in accordance
with Virginia Regulations at (VR) 680-14-01.
All of the alternatives would also comply with Section
10.5.H of the Virginia Hazardous Waste Management Regulations
(VHWMR) by instituting long-term monitoring of the ground water
both upgradient and downgradient of the Site.
3. Lonq-Term Effectiveness and Permanence
This evaluation criterion addresses the long-term protection
of human health and the environment once remedial action cleanup
goals have been achieved, and focuses on residual risks that will
remain after completion of the remedial action.
All of the alternatives provide equal long-term
effectiveness and permanence regarding existing structures, K001
waste, and closure of the unlined pond.
Alternatives 3, 4, 5, and 6 provide the greatest degree of
long-term effectiveness and permanence regarding soils and ground
water because they provide for either treatment or offsite
disposal of the surface and DNAPL soils as well as treatment of
ground water. Under Alternatives 3, 4, and 5, the surface soils
and the DNAPL soils would be excavated and treated to health-
based levels prior to onsite disposal. The treated soils would
then be covered with six inches of clean soil. Under Alternative
6, the surface and DNAPL soils would be excavated and properly
disposed of in a RCRA Subtitle C landfill. Under all four of
these alternatives, the contaminated ground water would be
collected, treated to meet requirements equivalent to those of a
VPDES permit and discharged to North Run Creek. Institutional
controls would be implemented under each of these four
alternatives to prohibit the use of the ground water at the Site
and to preclude residential development of the Site. These
Alternatives offer the most long-term effectiveness and
permanence because they remove hazardous substances from the
Site.
For Alternative 2, the risks posed by soil contaminants
through the potential exposure pathways would be eliminated only
as long as the cap and slurry wall were properly maintained.
Alternative 2 therefore offers the least long-term effectiveness
and permanence. Because the contaminant sources (soil and ground
water) are contained and not treated or removed, long-term
threats posed by remedy failure would remain. Ground water
within the boundaries of the Site would not be treated. However,
this would pose little risk to human health at the Site. The
ground water within the Site would not be used for domestic
purposes since institutional controls would be implemented as
part of the remedy, prohibiting use of ground water onsite and
precluding residential development of the Site.
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4. Reduction of Toxicitv. Mobility, or Volume through Treatment
This evaluation criterion addresses the degree to which a
technology or remedial alternative reduces the toxicity,
mobility, or volume of a hazardous substance. Although Section
121 (b) of CERCLA, 42 U.S.C. Section 9621(b), establishes a
preference for remedial actions that permanently and
significantly reduce the toxicity, mobility, or volume of
hazardous substances, EPA expects to use a combination of
treatment and engineering controls to achieve protection of human
health and the environment, as set forth in the NCP at 40 C.F.R.
Section 300.430(a)(iii). EPA's expectations are that treatment
should be utilized whenever principal threats occur and that
containment will be considered for wastes that pose a relatively
low long-term threat or where treatment is impracticable.
Based on published data, it is anticipated that Alternatives
3, 4, and 5 would all reduce the toxicity of the contaminants in
the surface soil, DNAPL soil and ground water by removing and/or
destroying the organic contaminants. However, for all of these
alternativesr the actual effectiveness of the different
technologies would have to be confirmed by treatability testing
performed during the design phase.
All of the alternatives equally reduce the toxicity,
mobility, or volume of K001 waste and existing water in the
unlined pond. In all of the alternatives, the K001 waste would
be excavated, dechlorinated if it contains excessive levels of
dioxins/furans, and incinerated. The only difference between the
alternatives is that the incineration would take place onsite
under Alternative 4 and offsite under the other alternatives.
The treatment of the surface water in the pond would be the same
under all of the alternatives.
In Alternative 3, the LTTD treatment process would remove
the organic contaminants (PCP and PAHs) from the surface and
DNAPL soils. Once removed from the soil, the organics would be
captured onto carbon adsorption beds. The beds would then be
regenerated offsite, destroying the organic contaminants. The
LTTD-treated soil and remaining surface soil exceeding the
cleanup level for arsenic would then be treated to immobilize
inorganic contaminants. The organic contaminants in the ground
water would be substantially removed through the carbon
adsorption water treatment process. The organic contaminants
would be captured during this process and destroyed offsite in
the regeneration process. If inorganics exceed the substantive
requirements of a VPDES permit, additional treatment would be
required to meet these requirements.
In Alternative 4, the incineration treatment process would
destroy all of the organic contaminants and volatilize the
inorganic contaminants from the surface and DNAPL soils. The
53
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incinerator ash and the remaining surface soil which exceeds the
cleanup level for arsenic would be treated to immobilize the
inorganic contaminants in the soil. The organic contaminants in
the ground water would be substantially removed through the
carbon adsorption water treatment process. The organic
contaminants would be captured during this process and destroyed
offsite in the regeneration process. If inorganics exceed the
substantive requirements of a VPDES permit, additional treatment
would be required to meet these requirements.
In Alternative 5, the solvent extraction treatment process
would remove the organic contaminants from the surface and DNAPL
soils into the solvent used in the process. The organics would
then be removed from the solvent and dechlorinated onsite to
treat the dioxins/furans. Following dechlorination, the organics
would be destroyed in an offsite incineration treatment process.
The solvent extraction-treated soil and remaining surface soil
which exceeds the cleanup level for arsenic would then be treated
to immobilize the inorganic contaminants in the soil. The
organic contaminants in the ground water would be substantially
removed through the carbon adsorption water treatment process.
The organic contaminants would be captured during this process
and destroyed offsite in the regeneration process. If inorganics
exceed the substantive requirements of a VPDES permit, additional
treatment would be required to meet these requirements.
In Alternative 6, the only reduction of toxicity, mobility,
or volume through treatment would occur in the treatment of the
contaminated ground water. The organic contaminants in the
ground water would be substantially removed through the carbon
adsorption water treatment process. The organic contaminants
would be captured during this process and destroyed offsite in
the regeneration process. If inorganics exceed the substantive
requirements of a VPDES permit, additional treatment would be
required to meet these requirements. Under this alternative
there would be no treatment of the surface or DNAPL soils.
In Alternative 2 there would be no reduction of toxicity,
mobility or volume of the contaminated soils or ground water
through treatment because none of these media are treated. In
Alternative 2, surface soil, DNAPL soil, and ground water is
remediated by constructing a capping system and slurry wall.
5. Short-Term Effectiveness
This evaluation criterion addresses the period of time
needed to achieve protection of human health and the environment,
and any adverse impacts that may be posed during the construction
and implementation period of a remedy, until cleanup goals are
achieved. The time for completion of the remedial actions for
each of the alternatives listed below does not include the time
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for long-term ground water monitoring, which will be required for
all of the remaining alternatives. All of the timeframes listed
below are estimates.
All of the alternatives would be equal in short-term
effectiveness regarding the demolition, decontamination, and
offsite disposal of the existing structures, washing the existing
gravel cover, and the treatment of the surface water in the
unlined pond. The water from decontaminating the existing
structures and washing the existing gravel cover will be
collected. This collected water, as well as the surface water in
the unlined pond, will be treated in the onsite water treatment
system and discharged to North Run Creek. Alternatives 2, 3, 5,
and 6 would all be equal in short-term effectiveness regarding
the excavation, dechlorination, and offsite disposal of the K001
waste, because the incineration of this waste occurs in an
offsite incinerator. The incineration of the K001 waste under
Alternative 4 would occur in an onsite incinerator.
Remedial action would be implemented in the shortest amount
of time under Alternative 2, approximately one year, and would
present the fewest short-term effects. During construction of
the approximately 11.5 acre cap and excavation for the slurry
wall and the approximately 7,200 cubic yards of surface soil in
the wetland areas, there would be a temporary increase in dust
production, noise disturbance, and truck traffic at the Site.
However, as the alternative with the least amount of excavation,
the soils would remain relatively undisturbed. Clean soil would
have to be brought into the Site to fill in the excavated areas.
Grading of the Site would result in minimal soil disturbance.
Alternative 3 would take approximately 2 years to implement.
The amount of soil excavation required (approximately 36,400
cubic yards of surface soil and approximately 8,600 cubic yards
of DNAPL soil) would be much more extensive than Alternative 2.
As such, the amounts of dust production, noise disturbance, and
truck traffic would also be significantly increased. However,
dust-suppression techniques would substantially control any dust
generated during the remedial action, protecting the workers at
the Site and residents in the area of the Site. The LTTD system
would be equiped with air pollution control equipment, allowing
it to meet federal and Virginia air emission standards and
eliminating any unacceptable risks to human health or the
environment.
Alternative 4 would take approximately 3 years to implement.
The amount of soil to be excavated would be the same as that
under Alternative 3. As such, dust-suppression techniques would
be required to control any dust that would be generated during
the remedial action to protect the workers at the Site and the
residents in the area of the Site. The incinerator would be
required to achieve at least 99.99 percent destruction and
55
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removal efficiency (ORE) for title organic contaminants in the soil
and meet other pertinent RCRA incineration standards at 40 C.F.R.
Part 264, Subpart O. The incinerator would include a stack, a
secondary combustion chamber or afterburner to maximize
combustion efficiency, and an air pollution control system such
as a Venturi scrubber or a baghouse filter to remove particulates
(and acid gases, if present) from the exhaust gases.
Alternative 5 would take approximately 2 years to implement.
The amount of soil to be excavated would be the same as that
under Alternative 3. Dust-suppression techniques would be
required to control any dust that would be generated during the
remedial action, protecting workers at the Site and residents in
the area of the Site. The solvent extraction process would not
require any air pollution control equipment because no air
emissions would be generated.
Alternative 6 would take approximately 1 year to implement.
The amount of soil to be excavated would be the same as that
under Alternative 3. Dust-suppression techniques would control
dust generated during the remedial action, thereby protecting
workers at the Site and residents in the area of the Site. Since
all excavated soil would be disposed offsite, an equal amount of
soil would be required to fill in the excavated area. This would
entail significantly more truck traffic in the area of the Site,
both in the offsite disposal of the contaminated soil and the
delivery of clean soil to be placed in the excavated areas.
6. Implementabilitv
This evaluation criterion addresses the technical and
administrative feasibility of each remedy, including the
availability of materials and services needed to implement the
chosen remedy.
The excavation, dechlorination treatment, and offsite
disposal of K001 waste would be identical under all alternatives.
In all cases, the KOOl waste would be incinerated (onsite under
Alternative 4 and offsite under the remaining alternatives) and
disposed of offsite. The removal and treatment of the surface
water in the unlined pond would also be the same under all of the
alternatives.
Alternative 2 could be easily implemented. Capping and
slurry wall construction have been used at many hazardous waste
sites. Construction of the slurry wall at the Site would be
compounded compared to standard slurry wall construction because
of the addition of a synthetic liner. The liner would be
required because the impermeability of bentonite may
significantly decrease when it is exposed to high concentrations
of creosote, water-soluble salts (copper, chromium, arsenic), or
fire retardant salts (borates, phosphates, and ammonia). Long-
56
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term maintenance and repairs of the cap and ground water
monitoring would be required to assure the integrity of this
alternative. Although the cap could be easily extended or
repaired, if needed, it would preclude direct soil treatment
unless it were removed. The excavation and offsite disposal of
the surface soil in the wetlands would have to be completed prior
to the enactment of Land Disposal Restrictions for F032, F034,
and F035 RCRA listed wastes. If not, these excavated soils would
have to be treated prior to disposal in an offsite facility.
Operation of either the LTTD and fixation systems under
Alternative 3 or the incineration and fixation systems under
Alternative 4 could be readily achieved once treatability tests
are completed and the systems' operating parameters are
established. The ability of LTTD to meet the cleanup goals for
PCP and PAHs needs to be confirmed in treatability tests.
Incineration is a highly reliable technology for organics
treatment; trial burns would still be undertaken to ensure the
cleanup levels could be met within air emission requirements.
The handling, treatment, and disposal of the approximately 45,000
cubic yards of contaminated soils would require a design plan
sequencing remedial activities to facilitate efficient removal.
Varying volumes or concentrations of contaminants in soils could
be easily handled. In addition, treatment of ground water is
routinely performed at many Superfund Sites. The carbon
adsorption ground water treatment system contemplated under both
of these alternatives would also require treatability tests to
assure the effluent limits would be met prior to discharge to
North Run Creek. The disposal of residuals in Alternatives 3 and
4 can be implemented since the availability of such facilities
is adequate. The spent carbon would require regeneration at an
offsite facility.
Excavation and offsite disposal of untreated surface and
DNAPL soils under Alternative 6 would be easily implemented as
long as the disposal is completed prior to the prohibition on
land disposal for F032, F034, and F035 RCRA listed wastes. After
the prohibition, these soils cannot be land disposed if they do
not meet treatment standards. The carbon adsorption ground water
treatment system could be easily implemented even though
treatability tests would be required to assure the effluent
limits would be met prior to discharge to North Run Creek. The
spent carbon would require regeneration at an offsite facility.
The handling, treatment, and disposal of the approximately 45,000
cubic yards of contaminated soils would require a design plan
sequencing remedial activities to facilitate an efficient
removal.
The solvent extraction treatment system under Alternative 5
would be the most difficult alternative to implement. Material
handling problems have been reported for full scale
implementation of solvent extraction at other locations. The
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ability of the solvent extraction process to meet the cleanup
goals for PCP and PAHs needs to be confirmed in treatability
tests. The carbon adsorption ground water treatment system under
this alternative would also require treatability tests to assure
the effluent limits would be met prior to discharge to North Run
Creek. The disposal of residuals can be implemented since the
availability of such facilities is adequate. The spent carbon
would require regeneration at an offsite facility.
7. Cost
Section 121 of CERCLA, 42 U.S.C. Section 9621, requires
selection of a cost-effective remedy that protects human health
and the environment and meets the other requirements of the
statute. The alternatives are compared with respect to present
worth cost, which includes all capital costs and the operation
and maintenance cost incurred over the life of the project.
Capital costs include those expenditures necessary to implement a
remedial action, including construction costs. All of the costs
indicated below are estimates.
Alternative 2 has the lowest present worth cost,
$10,001,000. Of the alternatives that include treatment of the
contaminated soil and ground water. Alternative 3, has the lowest
present worth cost, $19,129,000 followed by Alternative 6 at
$22,616,000 and Alternative 5 at a present worth cost of
$23,329,000. Alternative 4 has the highest present worth cost of
all of the alternatives, $27,396,000. The present worth costs
for Alternatives 2 and 6 include the cost of offsite disposal of
untreated soil in a RCRA Subtitle C facility. If the prohibition
on land disposal becomes effective prior to the completion of the
offsite disposal, the present worth costs of these two
alternatives would increase accordingly.
8. State Acceptance
The Virginia Department of Environmental Quality (VDEQ)
served as the lead agency for the Commonwealth of Virginia. VDEQ
has reviewed the remedial alternatives under consideration for
the Rentokil, Inc. site and has provided EPA with technical and
administrative requirements for the Commonwealth of Virginia.
VDEQ agrees with the analysis of alternatives presented in this
ROD and concurs with EPA's selected remedy discussed below.
9 . CoT'TOinitv Acceptance
On January 20, 1993, a public meeting was held at the
Henrico County Goverment Complex, Parham Road at Hungary Spring
Road, in Richmond, Virginia to discuss EPA's preferred
alternative as described in the Proposed Plan. A public comment
period for the Proposed Plan was held from January 8, 1993,
through March 8, 1993. The comment period was extended by
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request. Comments received during the public meeting and the
public comment period are discussed in the Responsiveness Summary
attached to this ROD.
I. Selected Remedy
EPA has selected a combination of Alternatives 2 and 3 to
remediate the contamination at the Site. Based on the RI/FS
findings and the nine criteria listed in Section H of this
Decision Summary, the combination of Alternatives 2 and 3
represents the best balance among the evaluation criteria.
Specifically, the selected remedy 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 vaste 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).
Excavation and onsite low temperature thermal desorption
(LTTD) treatment to remove PCP and carcinogenic PAHs (to the
Site-specific cleanup levels of 48 mg/kg and 5.1 mg/kg,
respectively) from soils removed during installation of the
dewatering system and slurry cutoff wall, and the soil
located at the following Site "hot spots": CCA Disposal
Area; Fill Area; and DNAPL-contaminated soils between the
surface and the hardpan which occur within 25 feet of the
concrete drip pad, the unlined pond, and the former blowdown
sump (a total of approximately 5,150 cubic yards of soil).
Chemical fixation of all LTTD treated soil which exceeds the
arsenic cleanup level of 33 mg/kg.
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Onsite disposal of all treated soils prior to construction
of the cap (offsite disposal, in accordance with Subtitle C
of RCRA, if any cleanup goal is not met after treatment).
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 vater 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
creation of wetlands of equal or better value, consistent
with the Location Specific ARARs listed at page 66 of this
ROD, and 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 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 of
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 the ground water at the
Site.
(7) Ground Hater Monitoring
Long-term ground water monitoring (at least 30 years).
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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 within the EPA acceptable risk range.
The performance standards for the major components of the
selected remedy include the 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 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 O. 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
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
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be moved to the area to be capped prior to construction of
the cap.
• To reduce the risk to human health and the environment via
the exposure pathways attributed to the "hot spots" at the
Site, approximately 5,150 cubic yards of soil will be
excavated, treated, and disposed onsite prior to
construction of the cap. The "hot spots" are defined as the
CCA Disposal Area, the Fill Area, and DNAPL-contaminated
soil between the surface and the hardpan within 25 feet of
the concrete drip pad, the unlined lagoon, and the former
blowdown sump. All excavated soil exceeding the cleanup
levels of 5.1 mg/kg carcinogenic PAHs and/or 48 mg/kg PCP
will be treated by the low temperature thermal desorption
(LTTD) process to a level at or below the cleanup levels.
All excavated soil exceeding the cleanup level of 33 mg/kg
arsenic will be treated by the fixation process to meet the
cleanup level. The organics vaporized in the LTTD system,
including PCP and the PAHs, will be removed with a carbon
adsorption system. The carbon will be regenerated at an
offsite facility approved by EPA. The LTTD system will be
equipped with air pollution control equipment, enabling it
to meet federal and Virginia air emission standards and
eliminate any unacceptable risks to human health or the
environment. All of the soil treated to the cleanup levels
will be backfilled onsite. All soils which, after
treatment, do not meet the cleanup levels for carcinogenic
PAHs, PCP, and/or arsenic will be disposed of offsite in a
RCRA Hazardous Waste Management (Subtitle C) facility
approved by EPA. 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, Subpart N. 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. All surface soil presently lying
within the area to be capped which exceeds any cleanup level
for the Site will not be capped until it has undergone
treatment as provided in (3), above. 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.
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• To reduce the risk to human health and the environment via
the exposure pathways attributed to the migration of ground
o 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, prior to
discharge to North Run Creek. The ground water will be
treated to comply with the substantive requirements
equivalent to those of a Virginia Pollution Discharge
Elimination System (VPOES) permit for discharge to North Run
Creek. 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 by
EPA.
(6) Institutional Controls
• To restrict access to the soil at the Site, institutional
controls to prohibit residential development on the Site
will be implemented. The institutional controls will
prevent exposure to the untreated soil at the Site as well
as prevent residential exposure to treated soils which meet
the cleanup levels established for the future light
industrial use scenario for the Site.
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• 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 thirty years. The ground water monitoring will include
sampling for arsenic, chromium, copper, zinc, PAHs, and PCP.
The appropriate number and location of the 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. The estimated present worth cost of
the selected remedy is $10,907,000. The present worth cost is
comprised of a capital cost of $9,797,400 and an annual operation
and maintenance cost of $72,200. Details of the costs for the
selected remedy are shown in Table 4.
J. Statutory Determinations
EPA's primary responsibility at Superfund sites is to select
remedial actions that are protective of human health and the
environment. In addition, Section 121 of CERCLA, 42 U.S.C.
Section 9621, establishes several other statutory requirements
and preferences. These specify that, when complete, the selected
remedial action for a site must comply with applicable or
relevant and appropriate environmental standards established
under Federal and State environmental laws, unless a statutory
waiver is justified. The selected remedy must also be cost-
effective and utilize permanent treatment technologies or
resource recovery technologies to the maximum extent practicable.
The statute also contains a preference for remedies that employ
treatment as a principal element. The following sections discuss
how the selected remedy for the Site meets these statutory
requirements.
Protection of ffyrn^n Health and the Environp^n^-
In order to meet the remedial objectives outlined in the FS,
the risks associated with exposure to the contamination at the
Site must fall within the acceptable risk range for carcinogens
(10~4 to 10~6) and the Hazard Indices for non-carcinogens must be
less than l. Implementation of the selected remedy will ensure
that Site risks fall within EPA's acceptable risk range.
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The selected remedy protects human health and the
environment by:
1. Eliminating direct contact with contaminants in surface
soils (0-2 feet) beyond the extent of the area to be
capped by moving these wastes into the area to be
capped;
2. Eliminating the principal threats from the DNAPL soil,
CCA Disposal Area, and the Fill Area by excavating,
treating, and properly disposing of these wastes;
3. Reducing contaminant levels in the existing structures
through removal of residual soil, decontamination and
offsite disposal;
4. Eliminating direct contact with the unlined pond by:
treating and discharging the surface water to North Run
Creek; excavating, treating, and disposing of the KOOl
waste; and closure and post closure care of the pond;
and
5. Eliminating direct contact with contaminants in the
ground water by: constructing a slurry wall and
dewatering system; collecting, treating, and
discharging ground water in accordance with the
substantive requirements of a VPDES permit; and
Implementing institutional controls to prohibit use of
the ground water at the Site.
Of all of the alternatives evaluated, the selected remedy
provides the best protection of human health without significant
adverse impact on the environment. No unacceptable short-term
effects or cross-media impacts would be caused by implementing
this remedy.
Compliance with Applicable or Relevant and Appropriate
Requirements
The selected remedy will comply with all Applicable or
Relevant and Appropriate Requirements (ARARs) as depicted in
Table 3.
Action-Specific ARARs:
• All debris will be cleaned of any residual soil and those
portions determined to require decontamination will be
handled in accordance with Part VIII of the VSWMR and 40
C.F.R. Part 268. The debris is considered a "special waste"
under Part VIII of VSWMR. Disposal of the debris will occur
at an offsite facility approved of by EPA.
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• Storage of the K001 wastes must conform with Sections 10.8
and 10.9 of the VHWMR.
• Closure of the unlined pond will be implemented in
accordance with the surface impoundments closure and post
closure requirements at Section 10.10.I of the VHWMR.
• The DNAPL, CCA Disposal Area, and Fill Area soils will be
treated by the LTTD and fixation processes, as appropriate,
prior to disposal onsite under the cap. The surface soil
located beyond the extent of the cap will be excavated and
disposed of onsite. Storage of soils containing hazardous
wastes in a waste pile must conform with Section 10.11 of
the VHWMR. All soil which cannot be treated to the health-
based levels developed for this Site must be disposed of in
accordance with Section 121(d)(3) of CERCLA and Subtitle C
of RCRA. Transportation to a RCRA-permitted treatment
and/or disposal facility must conform with RCRA regulations
at 40 C.F.R. Parts 262 and 263, the Department of
Transportation regulations at 49 C.F.R., and Part 7 of the
VHWMR.
• Substantive requirements of the Virginia Erosion and
Sediment Control Law will be achieved. The Henrico County
Code—Chapter 9, Erosion and Sediment Control Ordinance—
constitutes Virginia's requirements for erosion and sediment
control.
• Substantive requirements of the VPDES program must be
complied with for the discharge of treated water.
• All air emissions from Site activities must conform with
the Virginia Regulations for Control and Abatement of Air
Pollution provided at VR 120-01-01.
Location-Specific ARARs:
• All excavation in North Run Creek or Wetlands A, B, or C
or the placement of soil in Wetlands A, B, or C will take
place in accordance with: Section 404 of the Clean Water
Act, 33 U.S.C. § 1344; 33 C.F.R. Section 323; 40 C.F.R. Part
6, Appendix A; Executive Orders 11988 and 11990; the
Virginia State Water Control Law (Code of Virginia §§ 62.1-
44.2 g£ seq.); the Virginia Chesapeake Bay Preservation Act
(Code of Virginia §§ 10.1-2100 fit seq. 1; and Virginia Water
Protection Permit (VR 680-15-02). The Chesapeake Bay
Preservation Area Designation and Management Regulations (VR
173-02-01) are the implementing regulations for Virginia's
Chesapeake Bay Preservation Act. Henrico County ordinance
contains the local requirements for compliance with
Virginia's Chesapeake Bay Preservation Act.
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Cost-Effectiveness
The selected remedy is cost-effective because it mitigates
the risks posed by the Site contamination within a reasonable
period of time. Section 300.430(f)(l)(ii)(D) of the NCP requires
EPA to evaluate cost-effectiveness by first determining if the
alternative satisfies the threshold criteria: protection of human
health and the environment and compliance with ARARs. The
effectiveness of the alternative is then determined by evaluating
the following three of the five balancing criteria: long-term
effectiveness and permanence, reduction of toxicity, mobility, or
volume through treatment, and short-term effectiveness. The
selected remedy meets these criteria and is cost-effective
because the costs are proportional to its overall effectiveness.
The estimated present worth cost for the selected remedy is
$10,907,000. A breakdown of the present worth costs for the
selected remedy is provided at Table 4.
Utilization of Permanent Solutions and Alternative Treatment
for Resource Recovery) Technologies to the Maximum Extent
Practicable (MEP)
Despite treating a smaller volume of contaminated soil than
that included under Alternatives 3, 4, and 5, EPA has determined
that the selected remedy satisfies the statutory preference for
treatment as a principal element and represents the maximum
extent to which permanent solutions and treatment technologies
can be utilized in a cost-effective manner for remediation of the
Site. This is accomplished by treating the ground water at the
Site, as well as the principal threats associated with DNAPL-
contaminated soil in the perched unit; the CCA Disposal Area; the
Fill Area; the surface water and K001 waste in the unlined pond
to EPA acceptable risk levels. Of those alternatives that are
protective of human health and the environment and comply with
ARARs, EPA has determined that the selected remedy provides the
best balance of trade-offs in terms of long-term effectiveness
and permanence, reduction in toxicity, mobility, or volume
through treatment, short-term effectiveness, implementability,
and cost, while also considering the statutory preference for
treatment as a principal element and considering state and
community acceptance.
Regarding long-term effectiveness and permanence, the
selected remedy is equal to Alternatives 3, 4, 5, and 6. None of
the alternatives evaluated include treating all of the
contaminated soil at the Site because it would entail excavation
of the entire Site down to the bedrock. Alternatives 3, 4, 5,
and 6 have a higher degree of permanence by treating or removing
a larger volume of contaminated soil as opposed to constructing a
cap over the Site. However, the dewatering system included in
the selected remedy offers a higher degree of long-term
effectiveness regarding ground water. The dewatering system will
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TABLE 4
Present Worth Cost
Selected Remedy
Existing Structures
Demolition, Decontamination & Disposal 126,000
Unlined Pond
Remove & Treat Surface Water 126,000
Remove Sediments 1,000
Offsite Incineration of Sediments 133,000
Dechlorination of Sediments (if necessary) 97,000
Site Preparation 38,000
Excavate and Backfill Surface Soil (7,200 cubic yards) 87,300
LTTD and Fixation (5,150 cubic yards/6,695 tons)
Mobilization 750,000
Treatability Study 35,000
Excavation 41,000
Silt Fence/Dust Control 13,000
Load & Haul to LTTD Unit 30,500
LTTD Treatment 837,000
Load & Haul to Fixation Unit 30,500
Fixation Treatment 569,000
Backfill 21,700
Cap and Slurry Wall 3,391,000
Caisson and Ground Water Collection
Mobilization/Demobilization 100,000
Installation of 2 Caissons 550,000
Grouting 60,000
Install 4" Collection Laterals 160,000
Pumps, Fittings, and Process Control Unit 10,000
Install 2" PVC Piping 30,000
Holding Tank, 7,000 gal. 6,000
Install Concrete Pad for Tank 12,000
Ground Water Treatment 243,000
Construction Subtotal 7,498,000
Contingency 1,499,500
Health & Safety Plan and Equipment 149,900
Total Construction 9,147,400
Design, Engineering & Construction Management 650,000
Total Capital Cost 9,797,400
Annual Operation & Maintenance 72,200
Present Worth Operation & Maintenance 1,109,600
Total Present Worth Cost 10,907,000
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induce an inward movement of ground water within the cap and
slurry wall. Any failure of the cap or slurry wall would be
readily detected because a larger volume of ground water would
flow into the dewatering system and be captured and treated. On
the other hand, failure of the collection trenches included in
Alternatives 3, 4, 5, and 6 would not be detected by the
monitoring wells until contaminants had already breached the
collection trenches. Alternative 2, on the other hand, only
includes removal of the surface soil located beyond the cap and
treatment of the surface water and K001 waste in the unlined
pond.
Regarding reduction of toxicity, mobility, or volume through
treatment, Alternatives 3, 4, and 5 include treatment of
approximately 45,000 cubic yards of soil compared to
approximately 5,150 cubic yards under the selected remedy. Under
Alternatives 3, 4, and 5, surface soils (0-2 feet) would be
treated that are not treated under the selected alternative.
However, under the selected alternative, these soils would be
contained by the cap. Additionally, scientists currently
theorize that by dewatering the soil within the cap and slurry
wall, those DNAPLs remaining in the soil may mobilize and be
collected in the laterals of the dewatering system, after which
they would be treated and discharged to North Run Creek. Thus,
the selected remedy would reduce the toxicity and volume of the
DNAPLs in addition to treating the wastes listed above.
Approximately 70 cubic yards of K001 waste is the only reduction
of toxicity, mobility, or volume accomplished under Alternative
2.
Regarding short-term effectiveness, the selected remedy is
second only to Alternative 2. The selected remedy includes
excavation of more soil than that under Alternative 2 but less
than that included under Alternatives 3, 4, 5, and 6. Thus, the
short-term impacts associated with dust, noise, and truck traffic
would be less than that from Alternatives 3, 4, 5, and 6 but more
than Alternative 2. Also, the selected remedy is anticipated to
take 18 months to complete, six months more than Alternatives 2
and 6 and six months less than Alternatives 3, 4, and 5.
Regarding implementability, the selected remedy is second to
Alternative 2. Alternative 2 is the most implementable
alternative. Construction of a cap and slurry wall has been
performed at many Superfund sites, as has excavation and offsite
disposal of contaminated soil. The selected remedy is more
easily implemented than Alternatives 3, 4, 5, and 6. The
selected remedy would require treatability studies identical to
Alternatives 3, 4, and 5 to determe whether LTTD and fixation
would meet the cleanup goals determined for the Site. However,
the selected remedy would be more easily implemented because it
would not involve excavating such a large volume of soil.
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Regarding cost, the selected remedy has the second lowest
present worth cost, $10,907,000. Alternative 2, at $10,001,000,
has the lowest present worth cost. With a present worth cost of
$19,129,000, Alternative 3 has a present worth cost $8,222,000
more than the selected remedy.
In summary, the selected remedy was chosen to remediate the
Site because it is protective of human health and the
environment, complies with all ARARs, and is cost-effective. In
addition, this remedy satisfies the statutory preference for a
remedy that employs treatment that reduces toxicity, mobility, or
volume as a principal element.
Alternatives 3 and 4 are equal to the selected remedy
regarding protectiveness of human health and the environment,
compliance with ARARs, high degree of long-term effectiveness and
permanence, reduction of toxicity, mobility or volume through
treatment, and ease of implementation. However, these
alternatives are not as cost-effective as the selected remedy.
Although Alternative 6 meets all ARARs and has as much long-
term effectiveness and permanence as the selected remedy, it does
not reduce the toxicity, mobility or volume through treatment,
and may not be as implementable because the soil must be
completely excavated and disposed of offsite prior to the
enactment of the Land Disposal Restrictions. Alternative 6 also
has a higher present worth cost than the selected remedy and does
not fulfill the statutory mandate to utilize treatment
technologies to the maximum extent practicable and the preference
for treatment as a principal element.
Alternative 2 meets all ARARs, has the least short-term
effects, is the most easily implementable alternative, and, at
$10,001,000, has the lowest present worth cost of all of the
alternatives. However, Alternative 2 does not reduce the
toxicity, mobility or volume through treatment. In addition,
Alternative 2 does not fulfill the statutory mandate to utilize
treatment technologies to the maximum extent practicable and the
preference for treatment as a principal element.
Alternative 5 meets all ARARs, reduces the toxicity,
mobility or volume through treatment, and has as much long-term
effectiveness and permanence as Alternative 3. However,
Alternative 5 may not be as implementable as Alternative 3
because of the difficulties encountered in previous attempts with
this treatment process and has a present worth cost that is
$12,422,000 more than the selected alternative.
The Virginia Department of Environmental Quality has
concurred with the selected remedy.
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for Treatment .as a Principal Element
The selected remedy satisfies the statutory preference for
treatment as a principal element. The PCP, PAHs, and arsenic
contamination in the soil and ground water constitute the major
human health risks associated with the Site. The selected
alternative would remediate the principal threats at the Site
including DNAPL soil, surface water and KOOl waste in the unlined
pond, CCA Disposal Area, and Fill Area. The low temperature
thermal desorption treatment system will effectively remove the
PCP and PAHs from the soil by heating it to 400° F to 800° F.
The exhaust will then be treated by air pollution control
equipment to remove any entrained particulate material, enabling
the system to meet federal and Virginia emission standards.
Next, the air will be directed into a condenser where the PCP and
PAHs will be condensed for subsequent treatment in an onsite
carbon adsorption unit. The KOOl sediments will be incinerated
offsite. If the KOOl contains high levels of dioxins/furans, it
will be treated onsite with a dechlorination process prior to
shipment to an incinerator. Collected ground water, and that
recovered during excavation and dewatering of soils, as well as
water from the unlined pond, will be treated by the carbon
adsorption process. Finally, the debris will be decontaminated,
where necessary, prior to disposal.
K. Documentation of Significant Changes
The Proposed Plan was released for public comment on January
8, 1993. The Proposed Plan identified Alternative 3—onsite LTTD
and fixation treatment of subsurface soil contaminated with
DNAPLs and all surface soil; installation of collection trenches;
and onsite treatment of ground water—as the preferred
alternative. One of the other alternatives (Alternative 2)
presented in the Proposed Plan and the RI/FS included
construction of a RCRA Subtitle C cap and slurry wall. All of
the alternatives evaluated in the FS resulted in hazardous
substances remaining onsite because of the depth of the
contamination (up to 27 feet) and the nature of the contamination
(DNAPLs). The original preference for Alternative 3 was based in
part on the statutory preference for a remedy that employs
treatments that reduce toxicity, mobility, or volume as their
principal element and the need to treat the ground water at the
Site. During the public comment period, however, a proposal was
received which suggested addition of a dewatering system within
the cap and slurry wall, with onsite treatment of the ground
water ("Alternative 7"). The commenter stated that the
dewatering system would be effective in collecting DNAPLs once
the area within the cap and slurry wall is dewatered.
EPA, in consultation with the VDEQ, decided that the
devatering proposal would be more protective of human health and
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the environment regarding ground water and that the cap and
slurry wall were necessary in order to make the dewatering system
effective. Any breach of the collection trenches under
Alternative 3 would result in contaminanted ground water leaving
the Site while a breach of the selected alternative's cap and
slurry wall would result only in additional ground water entering
this area which would be collected in the dewatering system and
treated.
Alternative 3 did not include mitigation or restoration of
impacted wetland areas. Alternative 3 also did not include
remediation of DNAPLs below the hardpan. The dewatering system
presented in the selected alternative should be capable of
mobilizing and collecting the DNAPLs there.
Neither Alternative 2 nor the subsequently proposed
Alternative 7 address excavation and treatment of the CCA
Disposal Area, the Fill Area, or DNAPLs in the area above the
hardpan. The CCA Disposal Area and Fill Area were not
specifically referenced in the Proposed Plan since they would
have been remediated as part of the surface soil. Construction
of a RCRA Subtitle C cap precludes the necessity of treating all
surface soil. The selected remedy remediates the CCA Disposal
Area and Fill Area through treatment and disposal. Excavation
and treatment of the DNAPLs above the hardpan is also retained in
the selected remedy. However, the area of DNAPLs to be excavated
has been explicitly defined as the area within 25 feet of the
concrete drip pad, unlined pond, and the former blowdown sump.
These areas have been retained because they contain the largest
amount of DNAPLs, based on the documentation in the RI. Overall,
while the selected alternative treats a smaller volume of soils
as compared to Alternative 3, all soils are nevertheless
remediated, at about half the cost of Alternative 3.
Finally, the selected remedy includes the movement (without
treatment or disposal) of untreated surface soil and sediments
from the oxbow of North Run Creek into the area to be capped,
while Alternative 3 included onsite treatment and disposal of
soil and sediments lying outside the area to be capped.
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GLOSSARY
Administrative Record: An official compilation of documents,
data, reports, and other information that is considered important
to the status of and decisions made relative to a Superfund Site.
The record is placed in the information repository to allow
public access to the material.
Applicable or Relevant and Appropriate Requirements (ARARs): The
federal and state requirements that a selected remedy must
attain. These requirements may vary among sites and
alternatives.
Carcinogens: Substances which can or may cause cancer.
Comprehensive Environmental Response, compensation and Liability
Act (CERCLA): A federal law passed in 1980 and modified in 1986
by the Superfund Amendments and Reauthorization Act (SARA). The
Act created a Trust Fund, known as Superfund, to investigate and
clean up abandoned or uncontrolled hazardous waste sites.
Information Repository: A location where documents and data
related to the Superfund project are placed to allow the public
access to the material.
National Priorities List: EPA's list of the nation's top priority
hazardous waste sites that are eligible to receive federal money
for response under Superfund.
Operable Unit (on): A portion of a Superfund site that has been
conceptually separated from the rest of the site to allow for
easier management.
Record of Decision (ROD): A legal document that describes the
interim or final remedial action selected for a Superfund site,
why the remedial actions were chosen and others not, how much
they cost, and how the public responded.
Remedial Investigation/Feasibility study (RI/FS): A two-part
study of a hazardous waste site that supports the selection of a
remedial action for a site. The first part, the RI, identifies
the nature and extent of contamination of the site. The second
part, the FS, identifies and evaluates alternatives for
addressing the contamination.
Resource Conservation and Recovery Act (RCRA): A federal law
enacted in 1976 and amended in 1980 and 1984 designed to control
hazardous waste from the generation of the waste to its ultimate
treatment, storage, and disposal.
Risk Assessment: A means of estimating the amount of harm which a
Superfund Site could cause to human health and the environment.
The objectives of a risk assessment are (1) to help determine the
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need for action by estimating the harm if the site is not cleaned
up, (2) to help determine the.levels of chemicals that can remain
on the site and still protect human health and the environment,
and (3) to provide a basis for comparing different cleanup
methods.
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Rentokil, Inc. (Virginia Wood Preserving) Superfund Site
Richmond, Henrico County, Virginia
Responsiveness Summary
May 1993
This Responsiveness Summary documents public concerns and
comments expressed during the public comment period. The summary
also provides EPA's response to those comments. The information
is organized as follows:
• Overview
• Background on Community Involvement
• Summary of Comments and EPA Responses from:
(1) The Public Meeting
(2) Citizens
(3) Local Municipality
(4) Potentially Responsible Parties
I.
The public comment period for the Rentokil, Inc. Site began
on January 8, 1993. Although the comment period was initially
scheduled to end on February 8, 1993, it was extended until March
10, 1993, as requested. To facilitate commenting, EPA held a
public meeting on January 20, 1993, in the Board of Supervisors
Room at the Henrico County Government Complex, Parham Road at
Hungary Spring Road.
At the meeting, EPA discussed the Remedial Investigation
(RI) , including the Risk Assessment (RA) , and the Feasibility
Study (FS) reports performed for the site. EPA also presented
the Proposed Plan for eliminating and/or mitigating the public
health and environmental threats posed by the contamination
detected in environmental media at the Site. EPA explained that
the preferred remedy includes the following: demolition,
decontamination, and off site disposal of the existing structures;
removal and onsite carbon adsorption treatment of surface water
in the unlined pond; excavation, dechlorination treatment, and
off site disposal of the K001 sediments from the unlined pond;
excavation, low temperature thermal desorption and fixation
treatment, and onsite disposal of the contaminated surface and
DNAPL soil; collection and onsite carbon adsorption treatment of
ground water; long-term groundwater monitoring; and institutional
controls. Although the selected remedy was not one of the
alternatives presented to the public for comment, the components
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of the selected remedy were presented in Alternatives 2 and 3 of
the Proposed Plan.
The January 20, 1993, public meeting also provided the
opportunity for the public to ask questions and express opinions
and concerns. Residents questioned the current health risks, and
the extent to which these risks will be lessened by remediation.
Virginia Properties, Inc. and Henrico County prefer a modified
remedy which was submitted during the public comment period as
part of the comments from Virginia Properties, Inc.
ZZ. BACKGROUND OH COMMUNITY INVOLVEMENT
During May and June 1985, several articles were published in
local newspapers concerning contamination at the Site and
extension of the municipal water lines. Public concern over
possible water contamination at that time was very high. After
public water was supplied to residents northeast of the Site,
media coverage diminished and their immediate concerns about the
Site were alleviated. Community interviews were conducted in
July and August 1989 for the Community Relations Plan. Residents
near the Site indicated during the interviews that they were
moderately interested in the activities at the Site and wanted to
be kept informed. The interviews also revealed that the
community prefers to learn of Site activities through informal
mailings. Due to the fact that many residents are elderly,
public meetings were determined not to be the ideal communication
method.
The Henrico County Director of Public Health and the County
Supervisor have been informing residents on a one-to-one basis of
Site activities and recommend that this method continue to be
utilized as it has proven successful.
The local citizen environmental groups contacted in July
1989 had no involvement with the Site. Some groups contacted
were unaware of the Site, while others felt the Site required no
further attention.
The Virginia Department of Environmental Quality currently
has the lead on community relations activities for the Site.
Community Updates are sent to citizens on the mailing list four
times per year, or as significant developments occur. A Community
Relations Plan was drafted in April 1991, and an Information
Repository has been established at the Henrico County Municipal
Reference and Law Library.
The major concerns expressed during the remedial planning
activities are as follows:
- Residents want information concerning EPA activities
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(past, present, and future) conducted at the site;
- Effects of creosote, pentachlorophenol, chrome, copper,
and arsenic on children, adults, and animals;
- The quality of water supply;
- Air pollutants and their associated health impacts;
- Effects of media coverage on real estate values;
- The length of time for cleanup to be completed;
- Health and liability risks associated with Talley's Pond;
and
- Hazards of substances released into the air during
remediation.
III. SUMMARY OF PUBLIC MEETING COMMENTS AND EPA RESPONSES
Questions and comments presented at the January 20, 1993,
public meeting are summarized briefly in this section and are
grouped according to subject. The EPA response follows each of
the questions or comments presented.
A. Technical Comments/Concerns Regarding Remedial Alternatives:
At the conclusion of the presentation of the EPA preferred
remedy, Virginia Properties, Inc. was permitted to show a video
entitled "Virginia Properties-The Right Alternatives1* which
presented the company's comments on the Proposed Plan. Major
comments made in the video are summarized below, followed by the
EPA response.
1. Virginia Properties, Inc. stated that the concentrations of
contaminants below the hardpan are insignificant.
EPA Response; As determined in the Risk Assessment performed by
Dames & Moore, ingestion of ground water from below the hardpan
constitutes a human health risk of 1.9 x 10~2. This
significantly exceeds the EPA acceptable risk range of 10~4 to
10~6. In addition, DNAPLs (which are classified as principal
threats) have been detected below the hardpan in the area of
monitoring well DM-15.
2. Virginia Properties, Inc. stated that Alternatives 1, 2, and
3 (Alternatives 3, 4, and 5 as presented in the FS and Proposed
Plan) have little value because they either take too long to
complete, create further environmental risk, have not been proven
to be completely effective, or are unsightly processes.
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EPA Response; Alternatives 3, 4, and 5 are estimated to take
approximately two years to complete, while Alternative 2 is
estimated to take one year to complete. Since EPA has a
preference for treatment, the additional one year of time
implementing Alternatives 3, 4, or 5 is outweighed by the fact
that contaminants levels would be substantially reduced in
comparison to leaving the contaminants in place under Alternative
2. Alternatives 3, 4, and 5 all encompass excavation and
treatment of a large volume of soil. As such, dust suppression
techniques would be implemented to limit the amount of fugitive
dust from excavation. In addition, the treatment processes would
include air pollution control equipment so that the exhaust would
not pose any unacceptable risks. The incineration treatment
process has been shown to effectively treat the contaminants at
the Site. Based on past treatability studies, the LTTD treatment
process should effectively treat the contaminants. It is not
known at this time whether solvent extraction can effectively
treat the contaminants in the soil matrix. Regarding
"unsightliness", EPA evaluates alternatives based on the Nine
Point Criteria in the NCP. The Nine Point Criteria do not
encompass "unsightliness."
3. Virginia Properties, Inc. described Alternative 3 as low
temperature incineration.
EPA Response; The treatment process proposed in Alternative 3 is
low temperature thermal desorption (LTTD), not low temperature
incineration. Incineration is a treatment process which destroys
contaminants while operating at temperatures starting at 1700° F.
LTTD is an innovative treatment technology that treats soil
contaminated with hazardous substances by heating the soil to
relatively low temperatures (200-1000° F) so that contaminants
with low boiling points will vaporize (turn into gas) and,
consequently, separate from the soil. The vaporized contaminants
are collected and treated. The preferred remedy for the Site
included offsite incineration treatment of the collected
contaminants.
4. Virginia Properties, Inc. expressed concern that a test
period is required for Alternatives 3, 4, and 5 to evaluate the
effectiveness of the processes, and possible chemical reactions.
EPA Response; Treatability studies are required in order to
properly design any treatment system. EPA prefers that
treatability studies be performed during the RI/FS phase. Since
the treatability studies were not performed previously, they must
be performed during the design phase for the Site.
5. Virginia Properties, Inc. stated that the pumping operation
in Alternative 3 may require 30 or more years, due to the very
slow movement of groundwater.
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EPA Response; It is not known how long it would take to achieve
remediation of the ground water at the Site. EPA used a thirty
year period for costing purposes. It is possible that ground
water would require treatment much longer than thirty years.
6. Virginia Properties, Inc. expressed concern that Alternatives
3, 4, and 5 would require large scale excavation, which adds to
the environmental risk through the release of potentially harmful
substances into the atmosphere.
EPA Response; Almost all of the contaminants at the Site are
semi-volatile organic contaminants or metals. These types of
contaminants do not volatilize very easily. In addition, dust
suppression techniques would be utilized during all excavation at
the Site.
7. Virginia Properties, Inc. warned that Alternative 4 poses a
further risk to the environment because contaminants may be
released into the atmosphere as byproducts of burning.
EPA Response; The incineration process included in Alternative 4
would include the necessary air pollution control equipment to
meet the Federal and Virginia air emission standards. In
addition, a test burn would be conducted during the design phase
to determine the effectiveness of incineration on the destruction
of the contaminants at the Site as well as monitoring for
products of incomplete combustion.
8. Virginia Properties, Inc. stated that the no-action
alternative (Alternative 1) is not in anyone's interest, as the
harmful substances would eventually contaminate the groundwater
and surrounding areas.
EPA Response; EPA agrees that Alternative 1 is not protective of
human health and the environment and should not be selected for
the Site.
9. Virginia Properties, Inc. recommended that Alternative 2 be
selected to remediate the Site since it takes best advantage of
the geologic characteristics of the Site, minimizes all
environmental risks posed to the off-Site soil, water, and
ecology, makes a permanent chamber to contain the constituents,
and there is no risk of additional infiltration to off-Site
areas.
EPA Response: EPA agrees that a slurry wall constructed to the
bedrock and a RCRA Subtitle C cap could effectively contain the
contaminants at the Site, thus minimizing risks associated with
the Site. However, the slurry wall and cap must always be
maintained to assure protectiveness of the remedy. In addition,
Alternative 2 includes treatment of only the K001 waste in the
unlined pond. The NCP states a preference for treatment,
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especially for any principal threats associated with a site.
None of the principal threats associated with the Site-DNAPL
soil, CCA Disposal Area, and Fill Area-would be treated under
Alternative 2.
10. Virginia Properties, Inc. stated that Alternative 2 requires
a small amount of excavation, posing minimal risk of air
emissions during remediation, and requires no test period
because the technologies are well understood.
EPA Response: EPA agrees that the amount of excavation under
Alternative 2 is much less than that under Alternatives 3, 4, and
5. However, as stated previously, all excavation at the Site
would be performed using dust suppression techniques to minimize
fugitive dust emissions. Although treatability studies would not
be required under Alternative 2, tests must be performed during
the design phase to determine whether the slurry wall would
require a liner and to determine the appropriate composition of
the liner because of the ability of creosote to penetrate slurry
walls.
11. Virginia Properties, Inc. prefers Alternative 2 because it
provides for the reuse and aesthetic rehabilitation of the
property through the placement of topsoil, grass, and new
structures above the cap.
EPA Response; Although EPA Region 3 knows of Superfund sites
which have been converted to open space/recreation areas after
the construction of a cap, it is not aware of any Superfund sites
which were developed with light industrial/commercial structures
on top of a cap. In addition, Alternatives 3, 4, and 5 include
placement of six inches of topsoil on top of the treated soil.
These three alternatives include institutional controls which
prohibit only residential development of the Site after
remediation since the soil cleanup levels were determined based
on light industrial/commercial exposures.
B. Public Comments
1. The owner of Talley's Pond asked what will be done for North
Run Creek and Talley's Pond.
EPA Response; Arsenic has been detected in North Run Creek and
Talley's Pond but the highest levels of arsenic have been
restricted to the oxbow of North Run Creek, just north of the
site. The selected remedy includes removal of the sediments in
the oxbow of North Run Creek, just north of the Site. Also,
Talley's Pond will be re-sampled and the dredged sediments from
the pond will be sampled as part of the selected remedy.
2. The owner of Talley's Pond stated that, within the last three
years, swans and Canadian geese that were brought onto their
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property died.
EPA Response; According to the owner of Talley's Pond, wildlife
which were born at the pond thrive better than those which were
brought there. Since wildlife which were born at the pond have
had far greater exposures to whatever contaminants are/were
present, it is not clear that Site related contaminants are
responsible for the poor health of the wildlife. In addition, it
is impossible to determine the health of the wildlife prior to
their being brought to the pond.
3. The owner of Talley's Pond stated that tests on bluegills
taken from the pond showed the fish were contaminated.
EPA Response; As part of the RI, ten bluegill specimens were
caught and sampled for total metals analyses. Metal contaminants
associated with the Site are arsenic, chromium, and copper, all
of which were sampled and were below the detection limits.
However, organic analyses were not performed on the fish. Based
on this information, the selected remedy includes an additional
round of sampling of fish from the pond to determine if they are
safe to ingest.
4. The owner of Talley's Pond indicated that her husband dredged
the pond sediments in January 1989 and spread the dredged
sediments on the property. She expressed concern about friends
and passersby walking around the property while feeding ducks and
possibly being exposed to Site-related contaminants.
EPA Response; The first phase of the RI was performed from Nay
to August 1989. Samples were not taken of the dredged sediments
because EPA was unaware that sediments from Talley's Pond were
dredged and placed on the property prior to the RI. Based on
this information, the selected remedy includes sampling of the
dredged sediments. If the sediments exceed the Site-specific
cleanup levels, they will be excavated and disposed of offsite.
The excavated areas will be replaced with topsoil and seeded.
XV. SUMMARY OP CITIZENS' WRITTEN COMMENTS AND EPA RESPONSES
1. One commenter stated that there is no such thing as a
permanent capping/containment system and that Alternative 2 does
not fix the problem but leaves the mess where it is where it will
eventually start to leak.
EPA Response; Installation of a cap and slurry wall can be
effective in controlling contamination at a site. However, both
the slurry wall and the cap will need to be maintained to assure
protectiveness of human health and the environment. It is
conceivable that the containment system will eventually start to
leak. However, the selected remedy provides for a dewatering
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system within the cap and slurry wall. If the containment system
under the selected remedy should start to leak, water would be
drawn into the capped area and then be collected and treated.
By treating the most highly contaminated soil at the Site, the
selected remedy further limits the chance for any uncontrolled
release of contamination at the Site.
2. One commenter stated that it appears the LTTO treatment
system would provide for adequate air pollution safeguards.
EPA Response; Air emissions would be tested during the
treatability studies to determine what air pollution control
equipment is necessary to meet Federal and Virginia air emission
requirements.
3. One commenter asked that steps be taken to ensure total
containment of pollutants on the Site while the cleanup takes
place.
EPA Response; An Erosion and Sediment Control Plan will be
developed during the remedial design phase. Implementation of
the Erosion and Sediment Control Plan during remedial action will
control runon and runoff of surface water at the Site and
minimize impacts from sediment transport from the Site. During
the remedial action, dust control measures will be utilized to
minimize the amount of fugitive dust caused by earth-moving
operations. EPA will continue to assess conditions at the Site
as the remediation process continues to ensure human health and
the environment are protected.
4. The owner of Talley's Pond inquired as to the safety of her
and her family since the pond is on their property. She also
asked what are their responsibilities to the public which visit
the pond.
EPA Response; Without sampling results, EPA cannot determine
whether anyone would be at risk from exposure to the dredged
sediments. Since the sediments have been planted with grass
seed, the possibility of exposure to fugitive dust is greatly
reduced. The selected remedy includes sampling the dredged
sediments to determine if they pose unacceptable risks to human
health and the environment. Until the sampling results are
known, it is suggested that children not be allowed to play in
that area.
5. The owner of Talley's Pond stated that, should they ever
decide to dredge the pond again, they would be dealing with
contaminated soil.
EPA Response; The sediments in Talley's Pond have been sampled.
The results of the sampling have indicated some metals
contamination associated with contaminants from the Site. The
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levels have decreased from the-first to the second round of
sampling. EPA believes the reduction is due to the construction
of the sediment trap and berm in June 1992. However, EPA has
included additional sampling of the pond as part of the selected
remedy because the highest level of contaminants in the pond
sediments may not be detected at the previous sampling location.
Also, the previous sampling did not include testing for organic
contaminants. If the sampling results indicate that the
sediments pose unacceptable risks to human health or the
environment, they will be excavated and disposed of offsite.
V. SUMMARY OF LOCAL MUNICIPALITY COMMENTS AMD EPA RESPONSES
1. The County of Henrico researched literature on the Low
Temperature Thermal Desorption Process, and found no evidence of
the technology having been used at a wood preserving operation.
They are concerned that this is the first time LTTD would be used
on this type of facility and that contaminants may breach either
the LTTD treatment process or, during periods of heavy rains or
flooding, the ground water collection trenches.
EPA Response; LTTD is an innovative treatment process which has
been selected in 14 Records of Decision as of May 1991 (including
two Records of Decision for wood treating facilities). In
addition, performance data indicate that LTTD is capable of
removing PCP and PAHs from soil. Verification sampling plans
will be developed during the design phase to determine if the
LTTD process is treating the contaminated soil to the established
cleanup levels. The potential for ground water to breach the
collection trenches exists primarily when the trenches become
clogged with silt over time. The remedy selected by EPA includes
slurry walls and a dewatering system to contain the contaminated
ground water rather than the proposed collection trenches.
2. The County of Henrico is concerned that the offsite
transportation of soils and sludge in Alternative 3 would mean an
increased risk of transportation-related accidents involving
hazardous materials at an intersection on Parham Road that has no
traffic light.
EPA Response; K001 waste and material from the Fill Area
(including drums) are the only hazardous substances selected for
offsite disposal, with the possibility that the dredged sediments
and present sediments from Talley's Pond could also be disposed
of offsite if they pose unacceptable risks to human health or the
environment. In addition, debris from the demolition of the
remaining structures will be disposed of offsite. However, the
debris will be decontaminated, as needed, prior to
transportation. As part of the remedial action workplan, details
for transportation of the wastes offsite will be developed which
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will take into account the amount of traffic on Parham Road and
the fact that no traffic light exists.
3. The County of Henrico stated that Alternative 3 does not
detail the method of treatment of contaminated soils found off
the Rentokil property outside of the containment area.
EPA Response; On page 3 of the Proposed Plan, EPA defined the
"Site" as comprising the land occupied by the Rentokil (Virginia
Wood Preserving) facility as well as those portions of land
contiguous to the northcentral boundary and the southeastern
corner of the facility. The preferred remedy included
excavation, treatment and onsite disposal of the surface soil
from the Site, including areas contiguous to the Rentokil
facility, which exceeded the cleanup levels. The selected remedy
includes excavation and onsite disposal of the contaminated
surface soil located beyond the extent of the cap.
4. The County of Henrico expressed doubt that Alternative 3
would be completed in the estimated two years, given the
chronology of EPA's involvement at the Site. The County
questions whether this two year estimate contains sufficient time
to pretest the LTTD Process.
EPA Response; The Feasibility Study (FS) for the Site was
conducted by Dames & Moore under contract to Rentokil, Inc. The
timeframes for all alternatives included in the Proposed Plan are
those developed by Dames & Moore, with the only exception being
the timeframe for Alternative 6 which was developed by EPA. The
timeframes included in the Proposed Plan for all alternatives are
the estimated time required to construct the remedial action, and
do not include the time required to negotiate with the
potentially responsible parties to perform the work or the time
required to conduct the remedial design, including the
treatability studies.
5. The County of Henrico strongly recommends careful
consideration of Alternative 7 as a better solution than
Alternatives 2 or 3.
EPA Response; Virginia Properties, Inc. submitted comments which
suggested the addition of dewatering the area within the cap and
slurry wall area as a new Alternative 7. EPA believes the
addition of the dewatering concept in concert with the
construction of a cap and slurry wall offers more protection from
contaminated ground water than the collection trenches included
in Alternative 3. Therefore, the remedy selected by EPA includes
a cap, slurry wall, and dewatering system. However, in
accordance with the preference for treatment presented in CERCLA
and the NCP, EPA has also selected treatment of the principal
threats associated with the site-surface water and K001 waste in
the unlined pond, the CCA Disposal Area, Fill Area, and the DNAPL
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soil in the areas of the treatment pad, unlined pond, and the
former blovdovn sump.
6. The County of Henrico insists on the following, regardless of
the cleanup alternative selected:
-That testing be reinstituted at the test wells surrounding
the Rentokil Site before the remedial cleanup plan is
instituted, during the containment process, and upon
completion of the containment process in order to
demonstrate the effectiveness of the containment.
-That the Workplan require that all contractors develop a
traffic plan with and approved by the County of Henrico's
Department of Public Works, Division of Police and the
Division of Fire for the removal of hazardous waste material
from the site.
-That a copy of the Health and Safety Plan identified in the
contamination remediation process be filed with the County's
Division of Fire.
-That the remediation process meet all of the County's
erosion and sediment control regulations.
-Should EPA enter into negotiations with the owners of the
Rentokil Site, the county would like to be notified in a
timely manner so we may have input into the process.
EPA Response: Long-term ground water monitoring is part of the
selected remedy. EPA will determine the number and location of
the monitoring wells during design. EPA agrees that a baseline
of ground water data should be established by sampling the
monitoring wells prior to the start of the remedial action.
However, it is not necessary to perform sampling in excess of
that contained in the monitoring plan.
It would be beneficial if the County of Henrico's Department
of Public Works, Division of Police, and the Division of Fire
were to list their applicable concerns regarding the transport of
hazardous waste from the Site prior to the development of the
remedial action workplan so that this document may be able to
address these concerns.
A copy of the Health and Safety Plan for the Site will be
filed with the County of Henrico's Division of Fire.
An Erosion and Sediment Control Plan will be completed as
part of the remedial design. The Erosion and Sediment Control
Plan will meet the requirements of the Virginia Erosion and
Sediment Control Law which indicates the applicable regulations
of the county are to be addressed.
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EPA will issue Special Notice Letters to potentially
responsible parties at the Site, offering them the opportunity to
perform the remedial design and remedial action. EPA will notify
the County of Henrico after these letters have been issued.
7. The County of Henrico expressed concern over the possibility
of reuse of the Site.
EPA Response; Although EPA Region 3 knows of Superfund sites
which have been converted to open space/recreation areas after
the construction of a cap, it is not aware of any Superfund sites
which were developed with light industrial/commercial structures
on top of a cap.
VI. SUMMARY OF POTENTIALLY RESPONSIBLE PARTIES COMMENTS AND EPA
RESPONSES
1. Richmond Land Corporation stated that remedial cleanup goals
established for offsite areas should not contain the same
reduction factors such as limited exposure frequency, limited
ingestion rate, and low fraction ingested from contaminant source
because there is a large portion of contamination remaining in
off-Site areas.
EPA Response; The Site is comprised of the wood treating
facility property occupied by Rentokil, Inc. and the areas of
land contiguous to the northcentral boundary and the southeastern
corner of the facility. The definition of Site is based on the
soil sampling results of the Remedial Investigation. The only
off-Site areas which have levels of contamination of concern
would be the sediments in North Run Creek and, possibly, the
sediments in Talley's Pond. The cleanup levels determined for
the Site are the same for those areas on the wood treating
facility property as well as those areas comprising the Site
which are located beyond the wood treating facility property.
The Site-specific health based cleanup levels developed for the
Site are: 5.1 mg/kg for total carcinogenic PAHs, 48 mg/kg for
PCP, and 33 mg/kg for arsenic.
2. The Richmond Land Corporation stated that the risk assessment
does not adequately address the potential elevated risk hazards
associated with on-site workers and the community during periods
of excavation and remediation.
EPA Response; During the remedial action, dust-suppression
techniques will substantially control any dust generated to
protect workers at the Site and nearby residents.
3. The Richmond Land Corporation stated that the cost of
remediation does not include indirect costs due to the
devaluation of both the on-site property and the surrounding
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property, the cost of damage to the underlying ground water, and
the cost of restricted future land use.
EPA Response; According to the Guidance for Conducting Remedial
Investigations and Feasibility Studies Under CERCLA, OSWER
Directive 9355.3-01, the purpose of the cost evaluation criteria
is to evaluate the capital and operation and maintenance (O&M)
costs of each alternative. Capital costs consist of direct
(construction) and indirect (nonconstruction and overhead) costs
while O&M costs are post-construction costs necessary to ensure
the continued effectiveness of a remedial action. Indirect costs
may include engineering expenses, license or permit costs,
startup and shakedown costs, and contingency allowances. The
costs associated with the devaluation of property, damage to
underlying ground water, and restricted future land use are not
factors in this evaluation and, are not specifically evaluated
when selecting a remedy.
4. Richmond Land Corporation believes Alternative 2, the cap and
slurry wall, is not appropriate to remediate the Site and that
the remedy for the Site must address reduction of toxicity and/or
volume to facilitate long-term risk reduction and eliminate
impacts to surrounding properties.
EPA Response; The selected remedy includes treatment to reduce
toxicity and volume of the contamination at the Site as well as
containment to prevent further migration and exposure to
contaminants. Contaminated surface soil beyond the extent of the
cap will be excavated and backfilled onsite prior to construction
of the cap and the principal threats associated with the Site
(DNAPL, CCA Disposal Area, and Fill Area) will be excavated,
treated to health based levels, and disposed of onsite prior to
construction of the cap. Ground water will be removed with a
dewatering system, treated, and discharged to North Run Creek.
5. Richmond Land Corporation believes the estimates of the
extent of soil and ground water remediation required have been
based on inadequate data.
EPA Response; EPA believes a sufficient number of soil and
ground water samples were taken from monitoring wells constructed
to characterize the nature of contamination at the Site.
Additional sampling of both soil and ground water will occur
during the remedial design to more accurately define the extent
of Site contamination.
6. Richmond Land Corporation states that the Remedial Action
Plan does not identify steps that will be taken to ensure that
cleanup levels are met and that the areas proposed for excavation
to the hardpan are identified but the basis for the horizontal
and vertical extent is not established.
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EPA Response; To ensure that cleanup levels are being met during
treatment, a verification sampling plan will be developed during
the remedial design. The areas selected for excavation to the
hardpan include 25 feet around the treatment pad, unlined pond,
and the former blowdown sump.
7. Richmond Land Corporation believes the selected alternative
does not adequately address off-property impacts, including an
area of 200 ppm PAHs to the east of the property line.
EPA Response; The selected alternative referred to in this
comment is actually Alternative 3, which was identified as the
EPA preferred remedy in the Proposed Plan but was not selected in
the ROD. EPA does not believe the contaminant level at this
sample point poses an unacceptable risk to human health. The
sample result mentioned in the comment is for total PAHs. The
carcinogenic PAH fraction for this sample is 34 mg/kg. The
carcinogenic PAHs cleanup level (10~6 human health risk) for
ingestion of soil is 5.1 mg/kg. This cleanup level was developed
for surface soil (top two feet) where it is most likely soil
ingestion will occur. The sample point indicated in the comment
is at the hardpan, about five feet from the surface. Also, most
of the material in the area of this sample will be removed during
the excavation of the Fill Area and the construction of the
slurry wall.
8. Richmond Land Corporation stated that restoration of wetlands
is not evaluated.
EPA Response; Alternatives 2 through 6 all include excavation of
the top two feet of soil in the three wetland areas. Therefore,
the cost of restoring the wetlands would be almost the same for
all of these alternatives (Alternative 2 and the selected remedy
would be somewhat less since the cap will extend beyond the
northern property boundary). Although not included in the
Proposed Plan, the selected remedy includes revegetating all
dredged wetlands and replacing all capped wetlands, subject to
approval by EPA.
9. Richmond Land Corporation stated that no treatability studies
have been conducted.
EPA Response; EPA would prefer that treatability studies be
conducted during the RI/FS. Since treatability studies were not
performed during the RI/FS, they must be performed during the
remedial design. Performance data generated in other studies
indicate that the LTTD system will be capable of meeting the
cleanup levels of 5.1 mg/kg for carcinogenic PAHs and 48 mg/kg
for PCP. Based on the performance data, EPA does not believe a
fallback remedy is warranted.
10. Richmond Land Corporation stated that the ground water
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treatment system description is not adequate to evaluate costs.
EPA Response; The selected remedy includes a cap and slurry vail
to minimize ground water flow through the area beneath the Site.
The dewatering system in the selected remedy will only treat the
ground water within the cap and slurry wall.
11. Richmond Land Corporation has concerns regarding the waste
remaining on and off site under Virginia Properties' proposed
Alternative 7. Also, it would like to know what the land use
restrictions will be for Alternatives 2 and 7 and how the land
use restrictions will differ if a rigid versus non-rigid cap is
constructed.
EPA Response; The principal threats will be addressed by
excavating, treating, and disposing onsite the CCA Disposal
Area, Fill Area, soil to hardpan in the treatment pad, unlined
pond, and former blowdown sump areas. The surface soil beyond
the extent of the cap will also be excavated and disposed onsite.
Land use restrictions for all alternatives will be implemented to
prohibit use of the ground water at the Site and residential
development of the Site. EPA will decide during the remedial
design whether to construct a rigid or non-rigid cap. The effect
of the cap type on land use restrictions will be considered
during the evaluation.
12. The comments from Virginia Properties, Inc. propose a new
remedial alternative for the Site, Alternative 7, which is
actually a modification of Alternative 2. Specifically, the
proposed alternative includes a dewatering system in addition to
the remedial actions of Alternative 2. The purpose of the
dewatering system is to produce an intragradient condition within
the cap and slurry wall.
EPA Response; The dewatering system proposed by Virginia
Properties, Inc. may mobilize the DNAPL in the soil after the
area within the cap and slurry wall is completely dewatered, thus
increasing the possibility of capturing DNAPL in the horizontal
collectors. The remedy selected in the ROD combines the
containment of Alternative 2, the LTTD and fixation treatment of
Alternative 3 (but for a smaller volume of soil), and the
dewatering system proposed by Virginia Properties, Inc. The
selected remedy includes treatment of the soil to the hardpan in
the area within 25 feet of the treatment pad, unlined pond, and
former blowdown sump, as well as the CCA Disposal and Fill Areas
to address the principal threats associated with the Site, to
conform with the expectations of the NCP, and to meet the
statutory preference for treatment. Although the proposal
submitted by Virginia Properties, Inc. is superior to Alternative
2, it was not selected because it does not address the source
areas associated with the CCA Disposal and Fill Areas. In
addition, EPA selected excavation and treatment of the areas
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defined previously to assure reduction of the toxicity and volume
of the highest levels of DNAPL at the Site.
13. Virginia Properties, Inc. stated that EPA should use cleanup
levels which meet a 10~5 human health risk in final remedy
selection because failure to do so result is a "propagation of
conservativeness".
EPA Response; Quantitative risk assessments are performed to
determine whether threats to human health exist due to
environmental contamination. The quantitative evaluation of risk
requires that many assumptions be made regarding exposure as well
as inherent toxicity. In order to satisfy this obligation and to
ensure that human health is protected, EPA employs admittedly
conservative assumptions when calculating risk. The need to make
conservative assumptions arises from the uncertainties associated
with several parameters related to the assessment of risk,
including (but not limited to) observed adverse health effects
and subsequent toxicity criteria, derived from exposed laboratory
animals for application to the human population and the variation
in the general human population. However, this conservative
approach does not represent a worst-case scenario, but rather, a
reasonable maximum exposure (RME). .The intent of the RME is to
produce a conservative estimate that is still within the range of
possible exposures. At the same time, such methodology ensures
that EPA is able to meet its ultimate responsibility of
protecting the health of sensitive subpopulations such as young
children, the elderly, pregnant women, and the chronically ill.
14. Regarding long-term effectiveness and permanence, Virginia
Properties, Inc. states that EPA failed to address in the
Proposed Plan the degree of uncertainty that the LTTD treatment
system will be able to meet the cleanup levels for PAHs and PCP.
EPA Response; LTTD is an innovative treatment system which, as
of May 1991, has been selected as the treatment technology for
remediation of a total of 14 Superfund sites, including two wood
treating Superfund sites. Performance data from previous tests
indicate LTTD is capable of removing PCP and PAHs from soil.
Treatability tests will be performed during remedial design to
ascertain optimal operating parameters. Verification sampling
plans will be developed during the design phase to determine if
the LTTD process is treating the contaminated soil to the
established cleanup levels.
15. Regarding reduction of toxicity, mobility, or volume through
treatment, Virginia Properties, Inc. states that its proposed
Alternative 7 will achieve reductions in the toxicity, volume and
mobility of Site contaminants greater than those estimated for
Alternative 3.
EPA Response; The EPA evaluation criteria examine the reduction
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of toxicity, mobility, or volume through treatment for each
alternative. Containment does not reduce toxicity, mobility, or
volume through treatment because there is no treatment. In the
alternative proposed by Virginia Properties, Inc., only the
ground water recovered in the dewatering system is treated. As
such, the alternative proposed by Virginia Properties, Inc.
achieves much less of a reduction in toxicity, mobility, or
volume through treatment as compared to Alternative 3. The
alternative selected in the ROD combines the containment
provisions of Alternative 2, the devatering system proposed by
Virginia Properties, Inc. and the treatment technologies of
Alternative 3. Therefore, the selected alternative achieves a
greater reduction of toxicity, mobility, or volume through
treatment than does the alternative proposed by Virginia
Properties, Inc.
In addition, it is not known whether the horizontal drains
will effectively remove DNAPL from the soil. It is only
theorized at this time that, after the area within the cap and
slurry wall is dewatered, the ONAPL present will mobilize. This
method of dewatering an aquifer has not been utilized previously
for DNAPL removal. Thus, treatment of these wastes is not
assured.
16. Regarding short-term effectiveness, Virginia Properties,
Inc. states that EPA did not fully consider in the Proposed Plan
the risks associated with implementation of LTTD or the other
treatment alternatives considered.
EPA Response; The performance of LTTD at other sites indicates
there is little cause for concern over the effectiveness of this
form of treatment. Potential impacts associated with staging of
excavated soil and fugitive dust will be minimized through
implementation of dust-suppression techniques.
17. Regarding implementability, Virginia Properties, Inc. states
that implementation of its proposed Alternative 7 will not create
problems of administrative feasibility while LTTD poses both
technical and administrative feasibility problems.
EPA Response; By excavating a much smaller volume of soil, the
space limitations of the Site could be easily overcome with a
site implementation plan to coordinate all work at the Site
during remedial action.
Disposal of untreated surface soil in the area under the cap
is the same as the disposal of surface soil in the selected
remedy. Under the selected remedy, the treated soil would also
be disposed onsite prior to construction of the cap. Under
Virginia Properties' alternative, the excavated soil would either
be disposed of in an offsite RCRA-permitted facility or in the
area to be capped. Offsite disposal of the untreated soil would
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have to be accomplished prior to the soon-to-be enacted Land
Disposal Restrictions for F032, F034, and F035 RCRA listed
wastes.
18. Regarding cost, Virginia Properties, Inc. states that, if
treated soil must be transported and disposed offsite under
Alternative 3, the cost of the remedy would be $37,100,000. They
also state that Alternative 3 does not meet the NCP's mandate to
select a remedy that is cost-effective.
EPA Response; The present worth cost of the selected remedy has
been estimated by EPA at $10,907,000, which is within 10% of the
alternative proposed by Virginia Properties, Inc. The selected
remedy ranks higher than the alternative proposed by Virginia
Properties, Inc. in long-term effectiveness and permanence and
reduction of toxicity, mobility, or volume through treatment. As
such, the selected remedy is more cost-effective than that
proposed by Virginia Properties, Inc.
19. Virginia Properties, Inc. questions whether the preferred
alternative will comply with state and federal applicable or
relevant and appropriate requirements (ARARs), specifically the
VSWMR prohibition against onsite disposal of treated soil, and
the federal Land Disposal Restrictions (LDRs).
EPA Response: Regarding the VSWMR, EPA has acknowledged that, in
general, the VSWMR are ARARs. However, the newly issued
provision cited by Virginia Properties would appear to result in
a statewide prohibition of land disposal of hazardous substances.
Under Section 121 (d) of CERCLA, such a provision cannot be an
ARAR unless three conditions are met:
• The State requirement is of general applicability and was
adopted by formal means:
• The State requirement was adopted on the basis of
hydrologic, geologic, or other relevant considerations and
was not adopted for the purpose of precluding on-site
remedial actions or other land disposal for reasons
unrelated to protection of human health and the environment;
and
• The State arranges for, and assures payment of the
incremental costs of, utilizing a facility for hazardous
waste disposal.
Assuming that the first two conditions have been met (there is
nothing in the administrative record to demonstrate that they
have), there is no indication that the Commonwealth of Virginia
intends to satisfy the last condition. Thus, EPA has determined
that the provision cited by Virginia Properties is not an ARAR.
This determination is reinforced by the fact that the
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Commonwealth has not documented or identified the provision as an
ARAB, as required by the NCP.
The federal LDRs will only be applicable if RCRA hazardous
wastes, restricted from land disposal pursuant to 40 C.F.R. Part
268, are to be disposed of at the Site. Currently, there are no
LDRs in place for listed RCRA hazardous wastes at the Site. The
only wastes at the Site which could potentially trigger LDRs
would be wastes exhibiting a characteristic defined in 40 C.F.R.
Part 261, Subpart C. The only wastes to be disposed of at the
Site are the LTTD-treated soils. All LTTD-treated soils will be
subjected to a chemical fixation process prior to onsite
disposal. Chemical fixation should render the soils chemically
stable and, in such a state, the soils would not exihibit the
toxicity characteristic for arsenic or chromium. The chemical
fixation process has proven successful at other Superfund sites
in the Region, notably the C&R Battery Site in Virginia.
Therefore, these soils should not trigger the LDRs. Non-LTTD-
treated surface soils to be removed from beyond the area to be
capped, and then buried beneath the cap, are not "disposed,"
because they are being consolidated within the same area of
contamination. Thus, these soils are not subject to the LDRs.
20. Virginia Properties, Inc. submitted additional comments
(after the close of the public comment period) in a letter dated
May 24, 1993 in which it voices the opinion that implementation
of LTTD treatment in the selected remedy will result in
uncontrollable and unquantifiable costs and unnecessary delays.
Additionally, Virginia Properties, Inc. states that overall
protection of human health and the environment does not require
both treatment of soil to a 1 x 10*6 health based level and
construction of a cap and slurry wall containment system; rather,
they feel treatment to a 1 x 10"* health based level in
conjunction with the cap and slurry wall containment system would
be sufficient for protection of human health and the environment.
EPA Response; Treatability studies are required in order to
properly design any treatment system. Since treatability studies
were not performed by Virginia Properties, Inc. during the RI/FS
phase, they will be conducted during the design phase. The
purpose of the treatability study is to determine the proper
design and operating parameters of the treatment system to
optimize removal of contaminants while minimizing costs.
Although treatability studies were not performed on the Site
soil, EPA believes LTTD will be able to meet the cleanup levels
established in the ROD. LTTD is an innovative treatment system
which, as of May 1991, has been selected as the treatment
technology for remediation of a total of 14 Superfund sites,
including two wood treating Superfund sites. In addition, LTTD
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has been evaluated in the Superfund Innovative Technology
Evaluation (SITE) Program using the X*Trax Model 200 Thermal
Desorption System manufactured by Chemical Waste Management, Inc.
and the Low Temperature Thermal Treatment (LT3) System
manufactured by Roy F. Weston, Inc. The demonstration of the
X*Trax Model 200 Thermal Desorption System, conducted in May
1992, included treatment of 215 tons of soil and sediment
contaminated with polychlorinated biphenyls (PCBs) from the Re-
Solve Super fund Site in North Dartmouth, MA. PCBs are very
difficult to remove from soil and sediment, very much like PCP
and PAHs. PCB concentrations in the contaminated soil ranged
from 181 to 515 milligrams per kilogram (mg/kg). PCB
concentrations in all treated soil samples were less than 1.0
mg/kg and the average concentration was 0.25 mg/kg. The average
removal efficiency was 99.9%. This information is published in a
SITE Demonstration Bulletin, EPA540/MR-93/502, February 1993.
The exact concentration level of treated soil cannot be
determined without treatability studies. However, based on
results such as the above, EPA believes LTTD will be able to meet
the cleanup levels established in the ROD.
Virginia Properties, Inc. states in its comments that the
Site-specific cleanup levels should be based on a l x 10~4 risk
level because it is within the EPA allowable risk range, would
lessen the need for testing and study, and that the soil will be
placed in a the cap and slurry wall containment system which is
protective of human health and the environment.
EPA's allowable risk range is 10~4 to 10'6, with 10~6 being
the point of departure. According to the Preamble to the NCP,
"EPA intends that there be a preference for setting
remediation goals at the more protective end of the
range, other things being equal. Contrary to
assertions of some commenters, EPA does not believe
that this preference will be so strong as to preclude
appropriate site-specific factors."
The above was utilized in determining the cleanup levels for the
Rentokil, Inc. Site in that the cleanup levels determined for PCP
and PAHs at the Site are established at the 10~6 risk level while
the cleanup level for arsenic is established at the 10~5 risk
level because the 10~6 cleanup level is actually lower than the
Site-specific background level of arsenic.
In the remedy selection process, EPA must evaluate
alternatives with respect to the nine point criteria listed in
the NCP as well as meeting the statutory requirements of CERCLA
section 121.
Both the selected remedy and the remedy propounded by
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Virginia Properties, Inc. meet, the "threshold criteria" of
overall protection of human health and the environment and
compliance with ARARs. EPA has determined, based upon
consideration of information contained in the administrative
record, that the selected remedy strikes the best balance among
the five "primary balancing criteria": long-term effectiveness
and permanence; reduction of toxicity, mobility, or volume
through treatment; short-term effectiveness; imp lenient ability ;
and cost. The following is a synopsis of EPA's evaluation of the
selected remedy and the remedy propounded by Virginia Properties,
Inc. with respect to the five primary balancing criteria:
The selected remedy achieves more in terms of long-term
effectiveness and permanence because the residual risk (if
the containment system should fail) is lower than the remedy
proposed by Virginia Properties, Inc. because a much higher
volume of contaminated soil at the Site is treated;
The selected remedy achieves more in terms of reduction of
toxicity, mobility or volume through treatment because, by
utilizing the 1 x 10~6 risk level, a much higher volume of
contaminated soil at the Site will be treated in comparison
to the remedy proposed by Virginia Properties, Inc. plus, a
much greater amount of contaminants will be removed in the
selected remedy;
The remedy proposed by Virginia Properties, Inc. has greater
short-term effectiveness because the remedial action
objectives would be achieved more quickly than under the
selected remedy;
LTTD treatment is implementable, as has been demonstrated at
other sites;
Both alternatives are nearly equal in cost, the selected
remedy costing less than 10% more. Although reducing or
eliminating treatability testing of the LTTD treatment
technology would serve to reduce the cost of remediation of
the Site, this would be outweighed by the savings gained by
determining the optimum design and operating parameters of
the treatment system. It should be noted that most
Superfund sites require treatability studies.
In the opinion of EPA, Virginia Properties, Inc. has disregarded
two of the nine remedy evaluation criteria listed in the NCP,
namely, reduction of toxicity, mobility, or volume through
treatment and long-term effectiveness and permanence. EPA must
consider all nine criteria when selecting remedies for Superfund
sites.
Section 121 of CERCLA. contains a mandate to utilize
permanent solutions and alternative treatment technologies or
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resource recovery technologies to the maximum extent practicable.
By treating the wastes with LTTD to the 1 x 10~6 risk level, the
selected remedy will permanently reduce the volume of hazardous
substances remaining at the Site. Because the cap and slurry
wall system will have to contain less hazardous waste, compared
to the remedy proposed by Virginia Properties, Inc., the selected
remedy is likely to achieve more in terms of long-term
effectiveness and permanence, at only slightly higher cost (less
than 10%).
COMMUNITY RELATIONS ACTIVITIES AT RENTOKIL SITE
ACTIVITY
(Community Update mailings - four times per year)
Proposed to NFL
Notice to Residents of Environmental Concerns
Meeting with County Officials
Community Interviews for CRP
Information Repository established
Site Visit to prepare for CRP
VDWM assumes Lead role
Community Relations Plan Draft
Mailing List established
Meeting with County Officials
Community Relations Plan Final
Meeting with County Officials
News Release, Removal Action
Public Meeting Citizen Advisory mailed
Public Notice of Proposed Plan, public meeting
Public Comment Period begins
News Release on Proposed Plan
DATE
1/87
2/27/87
7/12/89
7/8/89
7/89
8/24/93
11/89
7/90
8/90
1/14/91
4/91
11/21/91
3/9/93
12/92
1/8/93
1/8/93
1/8/93
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Second Public Notice of Public meeting 1/18/93
Invitations distributed to residents 1/19/93
County Briefing
Proposed Plan Public Meeting 1/20/93
Public Notice of Extension of comment Period 2/8/93
Comment Period ends 3/10/93
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