United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R03-91/136
September 1991
&EPA Superfund
Record of Decision:
Saunders Supply, VA
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50272-101
REPORT DOCUMENTATION 1. REPORT NO. a.
PAGE EPA/ROD/R03-91/136
4. THeendSubtte
SUPERFUND RECORD OF DECISION
Saunders Supply, VA
First Remedial Action - Final
7. A0hor(*)
9. PtrfoniiiiiQ Or0cuuzB0Ofl Ncnw wwS Aodivss
12. SponMting Organiz«tk>n Hum end Addrae*
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
3. HBCtpwtii • Acocttton No.
5. ReportDtt*
09/30/91
6.
& Performing Orgenlnton Rept No.
10. ProlectrTttk/WorklMtNo.
11. Contracl(C)orQrent(G)No.
(C)
(G)
13. Type of Report* Period Covered
800/000
14.
15. Supplementary NotM
16. Afaetract (Unto 200 word*)
The 7.3-acre Saunders Supply site is an active lumber yard facility in the Village of
Chuckatuck, a rural area of the City of Suffolk, Virginia. Land use in the area is
predominantly mixed residential and commercial. The site is composed of the Saunders
Supply Company property and a portion of the adjacent Kelly property. Commercial
establishments and residences are to the east of the'facility, and a wooded area is
to the west. From 1964 to 1991, the Saunders Supply Company used the site to
chemically treat wood before distribution. Prior to 1984, treated wood was placed on
pallets located directly on the ground near the wood treating process area.
Subsequently, from 1984 to 1991 when the site ceased operations, treated wood was
air-dried on a concrete drip pad. These improper treatment and disposal processes
have contaminated onsite soil, sediment, and ground water. Principal site features
include the treatment facilities, a former conical burn pit area, a former earthen
separation pond, and a wastewater pond west of the site. Some drainage from the site
discharges to storm sewers adjacent to the site boundary. After the State
investigated the site, Saunders Supply was required to install monitoring wells,
excavate the contaminated soil around the conical burn pit area, and install a
(See Attached Page)
VA
17. Document Anelyete & Descriptor*
Record of Decision - Saunders Supply,
First Remedial Action - Final
Contaminated Media: soil, gw
Key Contaminants: organics (dioxin, PCP), metals (arsenic, chromium)
Ix ktenflflcfi/OpcfvCndtd Twm
ia AveilebUty Statement
1». Security CUM (This Report)
None
20. Security CUM (TW» Pege)
None
21. No. of Page*
69
22. Price
(See ANS1-Z3S.18)
See lnttruction» en /town*
OPTIONAL FORM 272 (4-77)
(Formerly NT1S-35)
Depertnefit of Commerce
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EPA/ROD/R03-91/136
Saunders Supply, VA
First Remedial Action - Final
Abstract (Continued)
recovery well. Treated water from the recovery well was recycled as the process water
for the chemical treatment of lumber. EPA conducted additional investigations that.
revealed the presence of pentachlorophenol (PCP), arsenic, and chromium in the ground
water. This Record of Decision (ROD) addresses all media impacted by site
contamination as a final remedy. The primary contaminants of concern affecting soil,
sediment, and ground water are organics including dioxins and PCP; and metals including
arsenic and chromium.
The selected remedial action for this site includes draining the wastewater from the
wastewater pond, followed by onsite or offsite treatment and discharge; excavating,
treating using dechlorination, and offsite disposal of 700 tons of sediment from the
wastewater pond and the former earthen separation pond; excavating, treating onsite
using low-temperature thermal desorption (LTTD), and offsite disposal of 24,300 tons of
soil and sediment from the storm sewer exceeding 1.46 mg/kg PCP; regenerating spent
carbon from the LTTD treatment process offsite; treating ground water during the
dewatering process prior to excavating the soil; discharging the treated water onsite
or offsite based on remedial design studies; testing the concrete pads for RCRA
characteristic hazardous wastes; scarification of the top 1 inch of the concrete pads
and treating the removed material using solidification if determined to be RCRA
characteristic waste, with subsequent offsite disposal along with the remainder of the
concrete pads; removing and plugging preexisting wells; cleaning and sliplining the
storm sewer; monitoring ground water; and implementing institutional controls including
deed and ground water use restrictions. The estimated present worth cost for this
remedial action is $20,485,000, which includes an annual O&M cost of $15,000.
PERFORMANCE STANDARDS OR GOALS: The chemical-specific soil clean-up level is
PCP 1.46 mg/kg. If ground water is discharged onsite, treated effluent must meet State
permit limits; or if discharged offsite, treated effluent must meet levels set by the
receiving facility.
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RECORD OF DECISION
SADNDERS SUPPLY COMPANY
DECLARATION
SITE NAME AND LOCATION
Saunders Supply Company
Chuckatuck, Virginia
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for the
Saunders Supply Company Site (the Site) in Chuckatuck, Virginia
which was chosen in accordance with the requirements of the
Comprehensive Environmental Response, Compensation, and Liability
Act of 1980 (CERCLA), 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. The information supporting
this remedial action decision is contained in the Administrative
Record for this Site.
The Virginia Department of Waste Management concurs with the
selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this
Site, if not addressed by implementing the response action selected
in this Record of Decision (ROD), may present an imminent and
substantial endangerment to public health, welfare, or the
environment.
DESCRIPTION OF THE REMEDY
This remedy will address all of the media impacted by the
contamination at the Site. It is not warranted at this time to
split the Site into smaller components called operable units to
address individual media. Based on the information derived through
the Remedial Investigation, the Site soils pose a principal threat
to human health. Since wastes will be left in place, long-term
monitoring of the ground water must be performed. The ground water
monitoring must test for the presence of pentachlorophenol (POP),
arsenic, and chromium because these contaminants have been detected
at elevated levels in the ground water to date.
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The selected remedy includes the following major components:
• Excavation, dechlorination treatment, and offsite disposal of
the K001 sediments from the wastewater pond and the former
earthen separation pond.
• Excavation, low temperature thermal desorption treatment and
offsite disposal of the Site soils and the sediments from the
storm sewer.
• Treatment of the ground water during the dewatering process
prior to excavating the soil.
• Scarification of the top one inch of the concrete pads,
solidification treatment of the removed material, and offsite
disposal of the solidified material and the remainder of the
concrete pads.
• Cleaning and sliplining of the storm sewer.
• Ground water monitoring.
« Institutional controls.
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.
Because this remedy will result in hazardous substances remaining
onsite, a review will be conducted no less often than each five
years after initiation of remedial action to ensure that human
health and the environment are being protected by the remedial
action being implemented.
Eclwin B. Erickson Date
Regional Administrator
Region III
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DECISION SUMMARY for the RECORD OF DECISION
8ADNDER8 SUPPLY COMPANY
A. Site Name. Location, and Description
The Saunders Supply Company site (the Site) is located in the
village of Chuckatuck, a rural area of the city of Suffolk, Virginia
(see Figure 1). The Site is comprised of the Saunders Supply
Company property and a portion of the Kelly property adjacent to the
Saunders property. The Saunders property occupies approximately 7.3
acres along State Route 10/32, which defines the eastern boundary of
the property. The Saunders Supply Company is an active lumber yard
which previously chemically treated wood before distribution. The
Saunders Supply Company also has a hardware store but that facility
is located several hundred feet south and upgradient of the wood
treating facility and is therefore not part of the Site.
The Saunders Supply Company facility is located in a mixed
residential and commercial area (see Figure 2). The Kelly Nursery
and residence is located immediately north of the facility. A
gasoline station and a residential subdivision are located south of
the facility. Commercial establishments and residences are located
east of the facility, and a wooded area is vest of the facility,
beyond which agricultural activity exists.
Buildings used primarily for retail operations are located on Godwin
Boulevard (State Route 10/32) on the eastern portion of the Saunders
property. Wood storage areas are located primarily on the southern
portion of the Saunders property. Wood treatment facilities, the
former conical burn pit area, and a former earthen separation pond
are located on the north central and northwestern portions of the
Saunders property. On the western portion of the Saunders property,
a pond was constructed to hold water used for process cooling
purposes. This pond is denoted as the wastewater pond.
The surficial slope of the property is toward a drainage ditch
immediately north of the Site and an intermittent stream adjacent to
and west of the Site. These surface water bodies discharge to
Godwin's Millpond (also known locally as Crump's Millpond), located
approximately 500 feet north of the Saunders property. Godwin's
Millpond is used as a municipal water source for the city of
Suffolk. Godwin's Millpond drains into Chuckatuck Creek.
Drainage from the vicinity of the Saunders wood treatment and wood
storage operations is also received by storm sewers (catch basins)
along Route 10/32, which discharge to a drainage swale and are
ultimately received by Cedar Creek, located approximately l mile to
the east of the Saunders property.
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Source: USGS T.S Mlnuw ScriM (Toooflrtpfttc) Qu*dr*nfto«: Chuckctuck, VlrglnM. H7«.
SCALE
1 Mil*
1 KUonwnr
Figural
SAUNDERS SUPPLY COMPANY LOCATION MAP
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Figure 2
SAUNDERS SUPPLY COMPANY
FACILITIES MAP
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B. site History and Enforcement Activities
The eastern portion of the Saunders property, along Godwin
Boulevard, was purchased in 1946 and operated as a lumber and
hardware retail store by the current owners. Prior to purchase, the
land was used for agricultural purposes. Onsite chemical treatment
of the lumber began in 1964 on the northwestern portion of the
Saunders property. During initial chemical treatment operations, a
5% pentachlorophenol (PCP) solution in No. 2 fuel oil was used in a
cylinder 5 feet in diameter and 32 feet long. A second cylinder 5
feet by 50 feet, was put into operation in 1971. The second
cylinder also treated lumber with a 5% PCP solution in No. 2 fuel
oil. In 1974, a third cylinder, 4 feet by 36 feet, was added. The
third cylinder, however, used a copper, chromium, and arsenic (CCA)
solution for the wood treatment. The 5 by 50 foot cylinder was
converted to the CCA process in 1981, and the 5 by 32 foot cylinder
was converted to the CCA process in 1984. The Saunders Supply
Company ceased all wood treating operations at the facility In June
1991.
When in use, the PCP treatment solutions were periodically drained
from the cylinders into a series of oil/water separators. The third
and final oil/water separator in the series was an unlined pond,
located southeast of the existing wastewater pond on the Saunders
property. This pond is denoted as the former earthen separation
pond. A crust-like residue that formed on the surface of the former
pond was occasionally burned as a training exercise for the local
fire department. The pond has since been filled in and covered over
by the Saunders Supply Company. The sediments which were at the
bottom of the pond exist in a layer under the surface of the soil.
These sediments are classified as a listed hazardous waste under the
Resource Conservation and Recovery Act (RCRA) as a K001 waste, 40
C.F.R. 261.32. Similarly, the sediments at the bottom of the
existing wastewater pond are also classified as a K001 listed
hazardous waste.
Sludge removed during annual maintenance of the PCP treatment
cylinders or associated oil/water separators was used on the roads
and/or around the lumber storage areas to control dust and weeds
from approximately 1966 through 1981. In 1969 a conical burner,
used primarily for the disposal of lumber scraps and sawdust, was
also used periodically to incinerate some of the sludges. The
conical burner ceased operations in 1974 and has since been removed.
Offsite removal of sludges generated by the PCP process took place
from 1981 through 1985, at which time the entire wood treating
process was converted to the CCA process. The burning of the PCP
sludges in the conical burner and the former oil/water separation
pond is the likely source of the dioxins detected on the Site.
During the past treatment operations, treated wood has been allowed
to dry onsite. Prior to 1984, treated wood was placed on pallets
located directly on the ground in the southern portion of the
property near the wood treating process area. From 1984 to 1991,
the wood was air-dried on a concrete drip pad that collected the
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excess chemicals. Because of the contamination resulting from the
previous practice of allowing the treated wood to drip onto the
ground, the soils at the Site contain F032 RCRA listed hazardous
waste, Federal Register 261.31.
Based on an investigation by the Virginia Department of Health,
Solid Waste Management Division and the Virginia State Water Control
Board, Saunders Supply Company installed monitoring wells, excavated
the contaminated soils around the conical burner area, and installed
a recovery well. The water from the recovery well was used as
process water for the CCA chemical treatment of the lumber, since
this process is a net consumer of water.
EPA proposed that the Saunders Supply Company Site be listed on the
National Priorities List (NPL) in 52 Fed. Reg. 2492, 2497, dated
January 22, 1987. On July 31, 1987, Saunders was informed of EPA's
intention to further investigate the Site pursuant to Section 104 of
the Comprehensive Environmental Response, Compensation, and
Liability Act of 1980 (CERCLA), 42 U.S.C. Section 9604, as amended
by the Superfund Amendments and Reauthorization Act of 1986 (SARA).
Although Saunders initially retained an engineering firm to prepare
a workplan for a Remedial Investigation/ Feasibility Study (RI/FS),
the Company informed EPA that it did not have the financial ability
to perform the RI/FS. As such, EPA utilized Superfund monies to
perform the RI/FS. General Notice letters were sent on July 12,
1990 to each of the officers of the Saunders Supply Company.
C. Highlights of Cowwinity Participation
The RI/FS and Proposed Plan for the Saunders Supply Company site
were released to the public in May, 1991. These documents were made
available to the public in both the administrative record and an
informational repository maintained at the EPA Docket Room in Region
III and at the Morgan Memorial Library in Suffolk, Virginia. The
notice of availability for these documents was published in the
Virginia Pilot and the Suffolk News Herald on May 23, 1991. The
purpose of the notice was to announce the beginning of a 30-day
public comment period on the Proposed Plan for the Site. The public
comment period was initially to be held from May 23, 1991, through
June 21, 1991. However, based on a request from the Saunders Supply
Company, the public comment period was extended until July 22, 1991.
In accordance with Section 117 (a)(2) of CERCLA, 42 U.S.C. Section
9617 (a) (2), a public meeting was held on June 4, 1991 at the Oakland
Elementary School in Chuckatuck, Virginia. At this meeting,
representatives from EPA and the Virginia Department of Waste
Management (VDWM) answered questions about problems at the Site and
the remedial alternatives under consideration. The majority of the
comments from the local citizens at the public meeting were chiefly
related to offsite ground water contamination, the need to dispose
of the soils offsite, and the impact of the remedy on the operations
of the Saunders Supply Company. A response to comments and concerns
received during the public comment period is included in the
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Responsiveness Summary, which is part of this Record of Decision
(ROD).
D. seooe and Role of Operable Unit or Response Action Within Site
Strategy
The selected remedy will address all of the media impacted by the
contamination at the Site; that is, the soils, the ground water in
the Columbia aquifer, the sediments in the former earthen separation
pond and the wastewater pond, the sediments in the storm sewers, and
the concrete drip pad. The levels of PCP found in the soils
constitute a principal threat at the Site. EPA 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 soils, 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 (Figures 3 through 6 show the
sampling locations):
• Grid surveying and topographic mapping;
• X-ray fluorescence surveying for arsenic, chromium, and
copper detection on shallow surface soil;
• Geophysical surveying;
• Air monitoring;
• Combustion product deposition modeling;
• Shallow surface soil sampling on both Saunders and Kelly
properties;
• Surface water, sediment and runoff sampling from surface
water bodies and drainage sewers within the study area;
• Subsurface soil boring and sampling;
• Ground water well installation and sampling;
• Aquifer testing; and
• Biota sampling in selected locations of surface water bodies.
A summary of the results from the RI sampling program are shown
below.
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F)gure3
SURFACE WATER AND SEDIMENT SAUPLINi
LOCATIONS WITHIN THE STUDY AREA
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Hour* 4
SURFACE WATER AND SEDIMENT SAMPLING
LOCATIONS ON AND ADJACENT TO
THE SAUNDERS PROPERTY
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Figure S
SUBSURFACE SOIL 8AUPUNO LOCATIONS
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Flflurae
WELL LOCATIONS
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Surfac* Soil
Concentrations of arsenic, total chromium, and copper above the
respective background levels of 5.7 mg/kg, 14.9 mg/kg, and 10.8
rag/kg were detected across most of the Saunders property and the
portion of the Kelly property adjacent to the former conical burn
pit. The highest concentrations of these three analytes were found
in the area surrounding the wood treating building where arsenic was
detected at 266 mg/kg, total chromium at 252 mg/kg, and copper at
158 mg/kg. The maximum level of hexavalent chromium detected was
1.836 mg/kg.
EPA has classified arsenic in Group A, a human carcinogen, based on
extensive evidence of human carcinogenicity through inhalation and
ingestion exposure. In regards to 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
based on positive animal studies and positive epidemiological
studies. In regards to noncarcinogenic effects, hexavalent chromium
is a respiratory tract irritant following inhalation and
occupational exposure to chromium compounds by inhalation have
resulted in changes in the kidney and liver. EPA has classified
copper as a Group D carcinogen—not classified. In regards to
noncarcinogenic effects, copper has toxic effects at high dose
levels including gastrointestinal disturbances, hemolytic anemia,
and liver damage.
PCP was not detected in the background surface soils. Detected
levels of PCP in surface soils ranged from 21 Mg/kg to 5100 M9/kg.
The only area on the Kelly property with a detectable level of PCP
(67 Mg/kg) in the surface soil is located immediately north and
adjacent to the former conical burn pit area. The highest levels of
PCP were detected in the vicinity of the former conical burn pit
area. These include where the conical burn pit was located (2600
Mg/kg), and the areas adjacent and south of the burn pit (5100
Mg/kg) and adjacent and west of the burn pit (3100 Mg/kg).
EPA has classified PCP as a B2 carcinogen, a probable human
carcinogen, because there is sufficient evidence of carcinogenicity
in animals but insufficient data in humans. In regards to
noncarcinogenic effects, there is a wide range of effects associated
with PCP, including hepatic toxicity, kidney toxicity, and central
and peripheral nervous system toxicity.
Because of the existence of many different isomers of dioxins, EPA
uses the Toxicity Equivalence Factor (TEF) to compare the differing
isomers to the most toxic isomer, 2,3,7,8 tetrachlorodibenzodioxin
(TCOO). Background levels of dioxins ranged from 0.005 ppb TEF to
0.0150 ppb TEF. Samples from two locations on the Kelly property
were consistent with background levels (0.0140 ppb TEF and 0.0110
ppb TEF). The other surface soil sample locations had levels which
ranged from 0.0770 ppb TEF to 3.249 ppb TEF. The highest levels of
dioxins were detected in the southern wood storage area (2.468 ppb
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TEF), and in the areas around the vastevater pond and the former
conical burn pit (3.249 ppb TEF, 2.100 ppb TEF, 1.294 ppb TEF and
1.164 ppb TEF).
EPA has classified TCOD-dioxin as a B2 carcinogen, a probable human
carcinogen, because there is sufficient evidence of carcinogenicity
in animals but insufficient data in humans. In regards to
nbncarcinogenic effects, there are four major toxic effects
associated with exposure to TCDD: chloracne, the wasting syndrome,
hepatoxicity, and immunotoxicity.
Background Total Petroleum Hydrocarbons (TPH) levels ranged from
nondetectable to 69.5 mg/kg. All surface soil TPH levels were at or
above background levels ranging from 64.9 mg/kg to 572 mg/kg, with
most locations ranging from 100 mg/kg to 200 mg/kg. Only one
location on the Kelly property had TPH levels above 200 (572 mg/kg).
No soil samples were taken beneath the concrete pads in the wood
treating area.
Surface Water and Sediment
All of the inorganics detected in the sediments in the study area
were found in levels which were within either the Site background or
the reported ranges of eastern United States soil metal
concentrations.
Several inorganics, such as iron, lead, and manganese, were detected
in surface water at elevated concentrations but were not considered
related to the activities at the Site because they are not
associated with the operations at the Site. Arsenic was detected in
all of the sampled locations along the intermittent stream,
including upstream of the Site (see Figure 7). In fact, the highest
level detected in the intermittent stream was the location upstream
of the Site. As such, the Site does not appear to be the source of
the arsenic in the intermittent stream. Arsenic was also detected
at two locations along Chuckatuck Creek discharging from Godwin's
Millpond. Based on the data collected, the arsenic levels in the
Chuckatuck Creek do not appear to be attributable to Saunders since
no arsenic was detected in Godwin's Millpond, which is located
upstream of the Chuckatuck Creek sampling locations. Arsenic was
also detected in the wastewater pond and the catch basins on the
Saunders property. The catch basins, which collect surface runoff
from the eastern portion of the Site, discharge to a drainage swale.
Samples collected from the drainage swale also had detectable levels
of arsenic. Arsenic levels in unfiltered surface water samples
ranged from nondetectable to 143 Mg/L, and from nondetectable to
55.9 Mg/L in filtered samples. The highest concentrations were
detected in the catch basins on the Site. The arsenic in the
sediments in the catch basins is considered to be from the Site.
The only surface water samples that contained detectable levels of
total chromium and copper were those collected from the catch basins
on the Site. Total chromium was detected at 135 pg/L and 153
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8AUNOER8
PflOPERTVl .RW-2
IOMIMM Si*t*h UNITS Sun «tai«i M
EMM el * MM WMM MiiM
Ffgur* 7
ARSENIC, CHROMIUM, AND COPPER
DETECTED M SEDIMENT AND
SURFACE WATERS
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in the unfiltered samples and below detection and 9.5 ng/L in the
filtered sample. Copper was detected at 181 jug/L and 207 nq/L. In
addition, hexavalent chromium was detected in one sample located
upgradient of the Saunders property (see Figure 7) .
PCP was detected in four sediment samples, all of which were
collected from the wastewater pond. Detected PCP concentrations
ranged from 1,200 M9/fcg to 230,000
Dioxins were detected in each of the 11 sediment samples, with
concentrations ranging from 0.0010 ppb TEFs in the intermittent
stream to 15.3 ppb TEFs in the wastewater pond sediment. Although
not found in the surface water of the wastewater pond, dioxins were
detected in the surface water of the catch basins at levels of 7.008
ppb TEFs and 5.851 ppb TEFs. However, it is assumed that this
detection is representative of the sediment from the catch basin,
not surface water runoff, because there was no runoff during sample
collection and a depression had to be created in the sediments of
the catch basin to pool any water there.
TPH was detected in every sampled sediment location with
concentrations ranging from 8.6 mg/kg at the reference location to
797 mg/kg in the catch basin. TPH was not detected in any of the
surface water samples.
ce Soil
None of the subsurface soil samples had concentrations of inorganics
that exceeded the published range for eastern United States soils.
PCP was detected in approximately half of the soil samples with
detected concentrations ranging from 45 to 1,900,000 pg/ltg. The
highest result was obtained from a sample collected in the vicinity
of the former earthen separation pond.
Dioxin concentrations exceeded 1 ppb TEF in three isolated areas
surrounding the wood treatment operation. A level of 7.691 ppb TEF
was detected south of the wood treating area while 20.56 ppb TEF was
detected west of the area and 11.939 ppb TEF was detected east of
the area.
Elevated concentrations of TPH were limited to areas immediately
surrounding the wood treatment building and in the vicinity of the
former earthen separation pond.
Ground Water
The unconfined Columbia aquifer, with a saturated thickness of 7
feet or less, is the uppermost water bearing unit underlying the
Site. No water supply wells exist in the Columbia aquifer in the
vicinity of the Site. Immediately underlying the Columbia aquifer
is a 2- to 7-foot thick clay unit which overlies the semi-confined
Yorktown aquifer. The thickness of the Yorktown aquifer in the
vicinity at the Site is unknown but is estimated to be 100 feet or
greater. The general flow of both the Columbia and Yorktown
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aquifers is towards Godwin's Millpond and the intermittent stream.
Two public water supply wells (Pembroke well numbers 1 and 2) and
the Kelly irrigation well have been identified as probably
withdrawing water from the Yorlctown aquifer. However, the majority
of the public water supply wells (Oakland, Suffolk Water Treatment
Plant and Fluoridation, and the Chuckatuck wells) withdraw water
from the Potomac group aquifers (Figure 8) which underlie the
Yorktown aquifer.
As shown on Figure 9, the concentrations of arsenic, copper, and
chromium from filtered samples did not exceed either the Virginia
Groundwater Standards or the Safe Drinking Water Act (SDWA) Maximum
Contaminant Levels (MCLs). However, the unfiltered sample result
for arsenic at MW-7-S, with a measured concentration of 82 yg/L,
exceeded the Virginia Groundwater Standard of 50 pg/L. Unfiltered
samples from MW-l-S (the background sample), MW-3-S, MW-4-S, MW-5-S,
MW-7-S, and MW-13-S in the Columbia aquifer, a Class II aquifer, had
concentrations of chromium which ranged from 55.2 M9/L to 238 ng/L,
thus exceeding either the Virginia Groundwater Standard of 50 /ig/L
or the MCL of 100 M9/L. The highest detected level of total
chromium in the Yorktown aquifer, a Class II aquifer, was the 61.9
Mg/L detected in an unfiltered sample from MW=10-D, located on the
Kelly property. Since all of the total chromium detections, both
onsite and off site, were from unfiltered samples and this one is the
only sample which exceeded the Virginia Ground Water Standard of 50
M9/L, this detection is considered as an isolated instance and is
not considered related to the operations at the Site.
PCP was detected in ground water samples collected from four of the
monitoring wells screened in the Columbia aquifer (Figure 10).
These shallow wells are located downgradient of the wood treating
facility. The concentrations of PCP detected ranged from 10 M9/L to
19,000 Mg/L (Figure 10). PCP was also detected in two monitoring
wells screened entirely in the Yorktown aquifer. One of the two
wells is located downgradient of the wood treating facility and
adjacent to the former conical burn pit. This well had measured
concentrations of PCP up to 160 M9/L. It should be noted that no
wells were placed in the Yorktown aquifer beneath the wood treating
area, or beneath the area of the Columbia aquifer where the highest
levels of PCP were detected. The only other deep monitoring well
that had a detectable concentration of PCP is downgradient of the
Site, along Godwin's Millpond. This well had a single detection of
PCP at the MCL level of 1 Mg/L that was qualified as an estimated
value. No PCP was detected in the Kelly irrigation well which is
located approximately 300 feet north of the Site. PCP was detected
in ground water collected from the recovery well which is one of the
preexisting wells on the Site. This well is located in the area of
the former conical burn pit. Based on well log information, the
placement of the recovery well screen across the Columbia aquifer
and the upper part of the Yorktown aquifer could be considered to
have caused the detection of the elevated levels of PCP in the upper
Yorktown aquifer. Since the exact location of the screens and the
integrity of the surface seals are not known, the data from this and
the other preexisting wells cannot reliably be used to qualify the
-8-
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SUFFOLK WATER TREATMENT
PLANT t FLUORIDATION WELL
INTAKE FOR SUFFOLK
OTY WATER SUPPLY
CHUCKATUCK
WELLS NOS. 1 & 2
SAUNDERS
OAKLAND
WELL
PEMBROKE
PEMBROKE
ChUCMUCk. VA 19*. nWDTMlN0 IWi.
Figures
WATER SUPPLY SOURCES
-------
•OH*TI»I
Flgural
ARSENIC.CHROtMUM. AM) COPPER
DETECTED IN OHOUNDWATtR IN uglL
-------
Flflura 10
PENTACHLOROPHENOL CONCENTRATIONS
(NOROUMOWATER
-------
extent of ground water contamination in an individual aquifer unit.
Concrete Pads
Since the concrete pads in the wood treating area were installed
after the complete conversion to the CCA process, the surface of the
pads should not be contaminated with PCP. No core samples of the
pad were collected for chemical analysis. Based on visual
observation only, the pads appear to be contaminated with copper,
chromium, and arsenic. Because the CCA is a water-based solution and
the fact that the pads were only in use for seven to eight years,
the contamination is considered at this time to be no deeper than
one inch.
Storm Sever Pipelines
The storm sewer pipelines that receive drainage from the Site are
located along Route 10/32. The storm sewer system 'includes
approximately 550 linear feet of 8-inch concrete pipe and five catch
basins. The storm sewer discharges to a drainage swale located
approximately 350 feet east of the Site. Elevated concentrations of
arsenic and dioxins have been detected in the surface water or
sediments collected from the two sampled catch basins along Route
10/32. The pipelines and the catch basins are both constructed of
concrete. Contamination may reach the drainage swale because the
contaminants which may have sorbed onto the concrete may desorb into
the storm water or be carried by it. Also, the contaminants may
have settled along any joints or cracks within the storm system and
may migrate to the adjacent soils or reach the drainage swale.
F. -?\1W^ry 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. Figure 11
provides a glossary of the key risk terms from the Baseline Risk
Assessment that are used in this section of the ROD.
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
-9-
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FIQURB 11
KEY RISK TERMS
Carcinogen: A substance that increases the incidence of cancer
in humans.
Chronic Daily Intake (CDI): The average amount of a chemical in
contact with an individual on a daily basis over a substantial
portion of a lifetime.
Chronic Exposure: A persistent, recurring, or long-term
exposure. Chronic exposure may result in health effects (such as
cancer) that are delayed in onset, occurring long after exposure
ceased.
»
Chronic Reference Dose (RfD): An estimate (with uncertainty
spanning perhaps an order of magnitude or greater) of a daily
exposure level for the human population, including sensitive
subpopulations, that is likely to be without an appreciable risk
of deleterious effects during a lifetime. Chronic RfDs are
specifically developed to be protective for long-term exposure to
a compound (as a Superfund program guideline, seven years to
lifetime.
Exposure: The opportunity to receive a dose through direct
contact with a chemical or medium containing a chemical.
Exposure Assessment: The process of describing, for a population
at risk, the amounts of chemicals to which individuals are
exposed, or the distribution of exposures within a population, or
the average exposure of an entire population.
Hazard Index (HI): The sum of more than one hazard quotient for
multiple substances and/or multiple exposure pathways. The HI is
calculated separately for chronic, subchronic, and shorter-
duration exposures.
Hasard Quotient: The ratio of a single substance exposure level
over a specified time period (e.g., subchronic) to a reference
dose for that substance derived from a similar exposure period.
Risk: The nature and probability of occurrence of an unwanted,
adverse effect on human life or health, or on the environment.
-------
Riak Assessment: The characterization of the potential adverse
effect on human life or health, or on the environment. According
to the National Research Council's Committee on the Institutional
Means for Assessment of Health Risk, human health risk assessment
includes: description on the potential adverse health effects
based on an evaluation of results of epidemiologic, clinical,
toxicologic, and environmental research; extrapolation from those
results to predict the types and estimate the extent of health
effect in humans under given conditions of exposure; judgements
as to the number and characteristics of persons exposed at
various intensities and durations; summary judgements on the
existence and overall magnitude of the public-health program; and
characterization of the uncertainties inherent in the process of
inferring risk.
Slope Factor: The statistical 95% upper confidence limit on the
slope of the dose response relationship at low doses for a
carcinogen. Values can range from about 0.0001 to about 100,000,
in units of lifetime risk per unit dose (mg/kg-day). The larger
the value, the more potent is the carcinogen, i.e., a smaller
dose is sufficient to increase the risk of cancer.
Weight-of-Evidence Classification: An EPA classification system
for characterizing the extent to which the available data
indicate that an agent is a human carcinogen. Recently, EPA has
developed weight-of-evidence classification systems for some
other kinds of toxic effects, such as developmental effects.
-------
highest potential risk to human health. The following six
contaminants of concern were judged to represent the major potential
health risks at the Site:
arsenic
copper
dioxin
PCP
hexavalent chromium
total chromium
Exposure 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 Sit* 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 of the
sampling performed as part of the RI, the five primary areas of
contamination associated with the Site are as follows:
• Soils in the vicinity of the former location of the conical
burn pit and earthen separation pond;
-10-
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• Sediments in the existing vastevater pond;
• Surface soils distributed throughout the Saunders property
and a portion of the adjoining Kelly property;
• A ground water plume adjacent to the conical burn pit and
wood treating area; and
• Water and sediment in runoff water catch basins.
The contaminants of greatest concern with respect to potential
current exposure are those in the surface soils which are
distributed throughout the Saunders property and a portion of the
Kelly property. Currently, exposure to sediments at the bottom of
the wastewater pond and ground water is very unlikely. However, if
the property is developed for residential use, future residents
could potentially be exposed. Similarly, exposure to the sediments
in the storm sewers also is very unlikely. However, continued flow
of runoff through the sewers may move the sediments to the drainage
swale or ultimately, to Cedar Creek. It should be noted that
sampling downstream of the catch basins indicated that the sediments
in the storm sewer posed no present risk to downstream receptors.
Exposure Scenarios
Three scenarios, encompassing the greatest potential exposure
pathways, have been evaluated in the Baseline Risk Assessment using
the Reasonable Maximum Exposure (RME). They are:
• Scenario 1: Worker exposure to soil contaminants;
• Scenario 2: Hypothetical future residential exposure to soil
contaminants; and
• Scenario 3: Residential ground water usage exposure.
Scenario 1 addresses outdoor exposure to adult workers under
existing conditions. 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. Exposures by these routes are most likely
to occur on the Saunders property, and currently Saunders Supply
Company employees are the main receptors. The key variables in the
RME worker exposure scenario include a soil ingestion rate of 100
mg/day, an exposure frequency of 250 days/year, an exposure duration
of 40 years, a skin surface area of 800 cm2, an exposure time of 8
hours/day, and an inhalation rate of 2.5 m3/day.
Scenario 2 addresses soil-related exposures that could occur if the
Saunders property were to be converted to residential use at some
time in the future. In this scenario, the same three exposure
pathways (ingestion and dermal adsorption of contaminants in soil
and inhalation of soil contaminants) have been evaluated for adult
-11-
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males and females, teenagers, adolescents, and young children. Key
variables in the future residential scenario are a soil ingestion
rate of 200 ing/day for children aged 1 to 6 and 100 mg/day for all
older receptor groups, an exposure frequency of 365 days/year, an
exposure duration of 30 years, a skin surface area of 1,600 cm2 for
adults and teenagers and 2,000 cm2 for children, an outdoor exposure
time of 16 hours/day, and an inhalation rate of 1.2 m3/hour.
Scenario 3 addresses potential exposures to PCP that could occur as
a result of future residential use of ground water from the Site.
The exposure pathways evaluated are ingestion of ground water,
dermal contact during showering, and inhalation of volatilized PCP
during showering. For simplicity, only adult male receptors were
evaluated in this scenario. Key variables in the residential 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, an exposure time while showering of 0.2 hours, and an
inhalation rate of 0.6 m3/hour.
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.
The upper 95% confidence limits on the arithmetic averages of
surface soil concentrations were used to estimate worker exposures
under the current worker exposure scenario. Since soil would be
excavated prior to residential construction, upper 95% confidence
limits for all surface soil, wastewater pond sediment, and soil
boring samples were used to estimate exposures in the future site-
use residential scenario. Table 1 presents the soil concentrations
used in exposure estimation for these two scenarios.
The only ground water aquifer used as a drinking water source in the
vicinity of the Sit* is the Yorktown aquifer. However, there
appears to be hydraulic communication between the upper Columbia
water-bearing zone and the Yorktown aquifer, probably by way of open
boreholes through the intervening clay layer. Also, it appears that
a breech in the clay confining unit exists in the vicinity of the
intermittent stream, downstream of the Site. Thus, the more
contaminated water in the Columbia aquifer could migrate down into
the Yorktown aquifer and increase the contaminant concentration
there.
Therefore, two exposure estimates were made for the residential use
scenario, one for ground water from the Yorktown aquifer and one for
ground water from the Columbia aquifer. Since there were only two
usable data values for the Yorktown aquifer, the maximum
concentration was used as the PCP exposure concentration. For the
Columbia aquifer, the upper 95% confidence limit was used for the
-12-
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Tafitol
COBCKBTHATIOHS OP COBTAIIX MUTTS U3BD
IH ESTIMATIBG KXPO3UU
TO SZTt SOIL
Contaminant
Arsenic
ChrooiuB (III)
ChroniuB (VI)
Copper
Pentachlorophenol
2.3.7.8-TCDO Equivalents
Soil
Current
Sit* Use
(mg/k?)*
106
119
0.46
<7
1.6
0.0019
Future
Site U«e
(•g/kg)««
16
25
0.32
ia
62.6
0.00241
Key:
•Upper 95% confidence limit on Man concentration
in surface soils collected on the Saunders
property only.
••Upper 95% confidence limit on >ean concentration
in all surface soil and soil borin? staples.
-------
PCP exposure concentration because there were six data values.
Table 2 presents the concentrations of PCP in ground water used in
exposure estimation for this scenario.
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. 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., IxlO"6 or 1E-6). An excess lifetime cancer risk of IxlO"6
indicates that, as a plausible upper bound, an individual has a one
-13-
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T«bl« 2
CmrciBTHATIOHS OP PCP
USID I* ESTXWTXBO KZPOSUU
TO SZTB OKOUWDMXTKK
Stapl* Numb«r PCP
Lov*r Aqoifcr
KW-8-D 160
MW-8-IX 11
Conontration 160
Oppvr Aqnifvr
HW-4-II 19,000
MW-4-S 13,000
KW-7-II JS
HW-7-S 10
MW-13-II 240
NW-16-II 4,100
Upp«c 95% Confi
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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.
In the absence of a remedial action, the total excess lifetime
cancer risks determined for all exposure pathways based on the RME
under the soil exposure scenarios are 3.6xlO~4 for the current
worker and 9.9xlO~4 for the future residential exposures. In other
words, without remedial action, approximately four additional people
per ten thousand have an increased chance of developing cancer as a
result of working at the Site and approximately one person per one
thousand would have an increased risk of developing cancer as a
result of living on the property.
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 risk to human health.
With an HI of 12, PCP would pose a human health risk through the
ingestion of ground water from the Columbia aquifer. PCP
concentrations in the Yorktown aquifer would not pose a risk to
human health because the HI is less than 1. This evaluation is
intended to provide a reference point for evaluating future ground
water risks; however, it does not represent actual exposures.
Although the Columbia and Yorktown aquifers have the characteristics
of Class II aquifers, domestic use of the aquifers is not likely to
occur since a public water source is already available.
Beside the above exposures, EPA must protect Godwin's Millpond, also
known as Crump's Millpond, which is a present day drinking water
source for the city of Suffolk. Although contamination has not
reached the Millpond, EPA has determined that PCP contamination in
the Columbia aquifer may reach the Millpond through a clay outcrop
in the intermittent stream west of the Site. Also, PCP
contamination in the Yorktown aquifer may reach the Millpond through
discharge of the Yorktown aquifer to the Millpond.
Site media which exceed the EPA acceptable risk range of 10"4 to 10~6
or have an HI equal to or greater than 1.0 are listed on Table 3.
Significant Sources of Uncertainty
Discussion of general limitations inherent in the risk assessment
process as well as the uncertainty related to some of the major
assumptions made in this assessment are included below:
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Table 1
U8K8
USE ASSISSMOR
•STuunt) ncsss umm
nmm uun> o» COODITIOBS
Exposure Scenario Receptor
Current Oat-Site Markers
Outdoor Soil Adult
Exposures
Adult
Adult
Future Da-Sit* Residential
Outdoor Soil Composite
Exposures Lifetime
Exposure Route Cancer Risk
Soil Ingestion 2.6 x 10~4
Soil Deraal 3.1 x 10~5
Absorption
Soil Particulate 6.3 x 10~5
Inhalation
Total 3.6 x Iff4
Soil Ingestion 7.7 x 10~4
Soil Dernal l.B x 10~4
Absorption
Soil Particulate 3.6 x 10"5
Inhalation
% of Total
Cancer Risk
74%
1%
18%
100%
71%
11%
4% .
Chaxticals Primarily
Responsible for
Cancer Risks in
Order of Importance
TCDD. Arsenic
TCDD, Arsenic
Arsenic, TCDD
TCDD, Arsenic, Pentachlorophenol
TCDD, Pentachlorophenol, Arsenic
Arsenic, TCDD, Chroniu* (VI)
Total
9.9 x 10
100%
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Table 3 (Coat.)
Cheaicala Primarily
Responsible (or
Exposure Scenario Receptor
Child
Future oat-Sit* Residential
Oroundwater Use Adult
Lower Aquifer
Orounduater Use Adult
Upper Aquifer
Exposure Route
Soil Ingest ion
.Soil De»al
Absorption
Soil Particulate
Inhalation
Total
Hater Inqestion
Hater Denial
Absorption
Airborne Chenical
Inhalation
Total
Hater Ingettion
Hater Derail
Absorption
Airborne Cheaical
Inhalation
Total
Cancer Risk
3.5 x 10"4
5.4 x 10"S
1.0 x 10"5
4.0 x 10~4
2.4 x 10"4
9.2 x 10"7
7.0 x 10~6
2.4 x 10"4
1.1 x 10"2
6.9 x 10"5
5.3 x 10~4
1.1 x 10"2
% of Total
Cancer Risk
14%
13%
3%
100%
97
3
100%
97
3
100%
Cancer Risks in
Order of latportance
TCDD, Arsenic, Pentachlorophenol
TCDD, Pentachlorophenol,
Arsenic, TCDD, Chroaiua
Pentachlorophenol
Pentachlorophenol
Pentachlorophenol
Pentachlorophenol
Pentachlorophenol
Pentachlorophenol
Arsenic
(VI)
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1. The use of the upper 95% confidence limit to estimate the soil
and Columbia aquifer ground water concentrations and the use of the
highest observed values to estimate the Yorktown aquifer
concentrations for the RME estimates. Although only two wells in
the Yorktown aquifer had detectable levels of PCP, it should be
noted that EPA did not place any monitoring wells in the Yorktown
aquifer beneath the area of the highest PCP contamination in the
Columbia aquifer because of the possibility of PCP escaping to the
lower aquifer. Therefore, the actual values of PCP in the Yorktown
aquifer underlying the wood treating area are unknown.
2. The assumption that the contaminants at the Site have reached
steady-state conditions.
3. The likelihood of the Saunders property being converted to
residential use. Although the property has been an industrial site
for about 25 years, it is presently bounded on three sides by
residential areas. Therefore, development of the Site in the future
for residential use is quite possible.
Environmental Risks
An ecological assessment was performed to determine if contaminants
related to the Saunders wood treating facility are present in nearby
surface waters and sediments in available concentrations sufficient
to cause adverse ecological impacts. As with the human health
assessment, the contaminants of concern for the ecological
assessment are arsenic, total chromium, hexavalent chromium, copper,
dioxin, and PCP.
For the purposes of the ecological assessment, a subset of
environmental receptors were chosen to serve as biotic focal
elements for analysis. Environmental receptors are populations and
communities of organisms potentially exposed to contamination.
Criteria for selection of particular species or groups of species as
focal elements are as follows:
• Intrinsic importance for economic or recreational reasons,
or for regulatory reasons (e.g., endangered species), or
the potential for serving as vectors for human exposure;
• Ability to provide an early warning signal of potential
effects, or particular and reliable sensitivity to
chemical stress;
• Indicative of alterations in ecosystem processes such as
energy flow or nutrient cycling or known to play a
critical ecological role in the food chain; and
• Being representative of or known to occur in habitats
potentially affected by contamination.
The Virginia Department of Conservation and Recreation's Division of
Natural Heritage database does not contain any records of natural
-15-
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heritage resources, such as rare species or exemplary natural
communities, in the study area. In addition, the Virginia
Department of Game and Inland Fisheries reported no wilderness
areas, natural areas, or scenic rivers in the immediate area of
Chuckatuck, Virginia. However, because of the proximity of the site
to the Great Dismal Swamp, EPA has determined that a biological
assessment must be completed and submitted for review to determine
if the Dismal Swamp Southeastern Shrew or the shrew's habitat is
present at the Site, in accordance with the Virginia Endangered
Species Act.
The primary contaminant exposure routes to the environment are
through the aquatic ecosystem. Therefore the ecological assessment
detailed the exposure of aquatic species to contaminants derived
from the Saunders property.
The quotient method is a standard approach for screening sample
locations for potentially toxic concentrations of chemicals. On the
basis of the quotient method, the levels of arsenic, total chromium,
and hexavalent chromium do not appear to pose a significant risk to
aquatic life in Godwin's Millpond or adjacent streams. However, it
is not possible to make a determination of the risk, if any, from
levels of copper and PCP in surface water.
The following were observed during the RI sampling:
• The presence of oily film and odor in sediments;
• The presence of a single tumor on one of the fish collected
from Godwin's Millpond;
• The spatial pattern of chemical contamination of sediments;
• Chronic toxicity of sediments on some invertebrates as
indicated in bioassays; and
• The low incidence of invertebrates collected from Godwin's
Millpond.
However, the contamination from the Site does not appear to be the
cause of these observed effects. The oily film and odor were noted
along the intermittent stream upstream and downstream of the Site
and at all sample locations on Godwin's Millpond. The presence of
a tumor on a bass collected from Godwin's Millpond is a possible
indication of chemical contamination. However, a definitive link of
the gross pathology of the fish tumor to the contaminants of concern
related to the Site cannot be made because a reasonably healthy fish
population was noted in the field survey and concentrations of
contaminants of concern were not found at toxic levels in the
surface water of aquatic habitats. Sediment toxicity bioassays have
shown chronic reproductive toxicity for Daphnia macma at all sample
locations, including the reference location, which is outside the
influence of the contaminants from the Site.
-16-
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In summary, the ecological assessment has found evidence indicating
the potential for adverse ecological impacts in sediments of
Godwin's Millpond and adjacent intermittent stream aquatic habitats.
The spatial extent of this contamination, however, indicates a
source or sources other than Saunders and the spatial distribution
of contaminants of concern in surface waters or sediments does not
provide any evidence that contaminants related to the Site are the
causal agent of adverse ecological impacts. Agricultural and waste
disposal activities in the area may contribute to the contamination,
but it is not possible to identify any source in particular from the
available data.
G. Description of Alternatives
In accordance with Section 300.430 of 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 the soils on the Saunders property and the adjoining
property, the ground water in both the Columbia aquifer and the
Yorktown aquifer, the sediments in the area of the former earthen
separation pond and the wastewater pond, the sediments in the storm
sewer along Godwin Boulevard, and the concrete pad in the wood
treating area. 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 the alternatives
reflect the descriptions in the 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.
Common Elements
Except for Alternative 1 ("No Action"), each remedial alternative
for the Sit* includes the following elements:
Limited Action. The preexisting wells that are screened across the
confining clay layer will be removed and plugged to prevent further
migration of PCP from the Columbia aquifer to the Yorktown aquifer.
Institutional Controls. Institutional controls, including deed
restrictions and restrictions on offsite ground water extraction,
will be implemented. The deed restrictions will prevent exposure to
contaminated ground water by prohibiting utilization of both the
Columbia aquifer and the Yorktown aquifer as sources of ground
water. The restrictions on the extraction of offsite ground water
will prevent the further migration of the PCP plume.
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around water Monitoring. Ground water monitoring will be used to
evaluate the protectiveness of the remedial action because waste
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 PCP, arsenic and chromium since
these were the only contaminants detected in the ground water during
the RI sampling.
Alternative 1 - Mo Action
Capital Cost: $ 19,000
Annual O&M Cost: $ 37,000
Present Worth: $320,000
Months to Implement: N/A
Section 300.430 of the NCP, 40 C.F.R. Part 300.430, requires that a
"no action" alternative be evaluated at every NFL 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 risk at the Site.
Alternative 2 - Capping with Ground Water Treatment
Capital Cost: $1,606,000
Annual O&M Cost: $ 201,600
Present Worth: $3,459,000
Months to Implement: 12
Alternative 2 consists of capping of the soils and sediments,
extraction and treatment of ground water from the Columbia aquifer,
surface sealing of the concrete pads, and cleaning and sliplining of
the storm sewers.
Because the capping would take place without any prior treatment,
the Land Disposal Restrictions (LORs) would not apply to Alternative
2. The cap would consist of approximately a 6 inch thick base
course and approximately a 2- to 4-inch thick asphalt pavement
covering an area of approximately 6.25 acres. The cap would require
subgrade preparation to properly drain the water under the asphalt
pavement and to provide a stable foundation. The cap would be
sloped up to the structural foundations, compacted, and sealed with
an asphalt sealer. Grading of the Site and the surrounding areas
may be required to minimize lateral seepage by diverting surface
runoff downgradient of the Site. A storm water management plan
would be required as would a long-term maintenance plan.
Maintenance, in the form of repairing cracks and recoating the
surface, would be required over the life of the cap (approximately
30 years). At the end of the 30 years, the cap may have to be
replaced. Since the soils would remain relatively undisturbed
-18-
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(grading would result in minimal soil disturbance), there would be
very little physical effects on the environment.
The asphalt cap would not eliminate water seepage through the soil.
As such, ground water from the Columbia aquifer, which has the
characteristics of a Class II aquifer, would have to be collected
and treated. Because of the limited flow in the Columbia aquifer
and the fact that PCP desorbs slowly, collection of ground water
would be accomplished with subsurface drainage trenches. The
drainage system would consist of a main collection or interception
trench along the downgradient (northern) edge of the Site with three
lateral trenches extending from the main trench into the area of the
wood treating operations. Two sumps would be installed in the main
collection trench to remove contaminated ground water from the
trench. The ground water would then be treated using granulated
activated carbon and discharged to Chuckatuck Creek at a point
downstream of the Millpond in accordance with the substantive
requirements of a Virginia Pollution Discharge Elimination System
(VPDES) permit.
The cleanup level for PCP in both the Columbia and Yorktown aquifers
is 1 Mg/L at the boundary of the plume. The spent carbon from the
ground water treatment system would require regeneration at an
offsite facility.
The existing concrete pads in the area of the wood treating area
would be sealed or coated with an impermeable material such as epoxy
or polyurethane sealants. Additionally, the concrete pad joints
would be fitted with chemically resistant water stops to ensure an
impermeable surface.
The existing 8 inch concrete storm sewers would be sliplined with a
flexible high-density polyethylene pipe of a slightly smaller
diameter. Before installing the liner pipe, the existing storm
sewer would have to be inspected with a closed circuit television to
identify any obstructions and thoroughly cleaned. After the liner
pipe is pulled into place, the service connections would have to be
reconnected to the new liner pipe. The annulus between the old and
new pipeline may be filled with grout.
Alternative 3A - Dechlorination with Offsite Disposal
Capital Cost: $25,824,000
Annual O&M Cost: $ 14,000
Present Worth: $25,934,000
Months to Implement: 36
Alternative 3A consists of onsite chemical dechlorination treatment
of approximately 25,000 tons of soils and sediments with offsite
disposal of all of the treated soils and sediments in a RCRA
Subtitle C permitted facility, backfilling of the area with clean
soil, scarification and solidification treatment, if necessary, and
offsite disposal of the treated material as directed by the Virginia
Department of Waste Management (VDWM) and offsite disposal of the
-19-
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remainder of the concrete pads in a solid waste landfill, and
cleaning and sliplining of the storm sewers.
The contaminated soils and sediments would be excavated and treated
onsite with the alkaline metal hydroxide/polyethylene glycol (APEG)
chemical dechlorination process within an enclosed batch reactor.
Vapors generated during treatment within the reactor would be
collected, condensed, and recycled through a washing process. Any
vapors that are not collected or condensed would require treatment
using activated carbon filters to prevent volatile organic
emissions. Such volatiles would not include PCP and/or dioxins.
The treated soil slurry would go from the reactor to a separator
where the soil and the reagent are separated. Excess reagent would
be decanted and/or removed through centrifugation and collected for
reuse. Any residual agent remaining in the soil would be removed by
aqueous washings with subsequent decanting or centrifugation. The
washwater would be recycled, since the process is a net consumer of
water.
After the treatment of all of the contaminated soils to meet the
soil cleanup level of 1.46 ppa of PCP, the reagent, which has been
continually recycled, would require disposal. Generally, this
liquid, which is mostly organic, is incinerated offsite.
Approximately 12,000 to 20,000 pounds of reagent would have to be
disposed. The spent carbon would be regenerated at an offsite
facility. Treated soil would be stockpiled or staged in accordance
with VHWMR Part 10 and sampled to determine the level of treatment
achieved.
LDRs would not apply to the soils because treatment standards have
not been established for these listed wastes. However, the LDRs
would apply to the K001 wastes, pursuant to 40 C.F.R. Section
268.33. Treatability tests would have to be done during the design
phase to determine proper operating parameters.
Currently, the concentration of PCP in the Columbia ground water is
at high levels near the source area and declines to nondetectable
levels within the Site boundary. Because the contaminated ground
water is limited to the Site, this alternative does not contain
long-tern ground water treatment. Rather, treatment of the ground
water will occur as the soils are dewatered during excavation, thus
substantially reducing the volume of contamination. The reduction
in the mass of contaminant on the Site will reduce the contaminant
available to partition or leach to the ground water.
If the concrete pads are classified as a RCRA characteristic
hazardous waste by the Toxicity Characteristic Leaching Procedure
(TCLP), remediation of the concrete pads would include scarifying or
removing approximately the top one inch of concrete from the surface
of the pads, and demolition of the remainder of the concrete pads.
Scarification im accomplished using a scabbier, which is a
pneumatically operated tool with piston heads. The pistons are
equipped with multipoint tungsten carbide bits for cutting and
chipping the concrete. Oust control measures would include pre-
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vetting the concrete, equipping the scabbier with a sprayer, and
using a vacuum attachment for dust collection. The material
generated from the scarification process would be solidified so that
it no longer has the characteristics of a RCRA waste. Disposal of
the treated material would be as directed by the VDWM. The
remaining concrete would be cleaned of any residual soil and
disposed in a solid waste landfill. If the concrete pads are not
classified as a RCRA characteristic hazardous waste, all of the
concrete could be disposed in a solid waste landfill without any
prior treatment other than cleaning of the residual soil.
The existing 8 inch concrete storm sewers would be sliplined with a
flexible high-density polyethylene pipe of a slightly smaller
diameter. Before installing the liner pipe, the existing storm
sewer would have to be inspected with a closed circuit television to
identify any obstructions and thoroughly cleaned. After the liner
pipe is pulled into place, the service connections would have to be
reconnected to the new liner.
Alternative 3B - Dechlorination with Onsite Disposal
Capital Cost: $13,977,000
Annual O&M Cost: $ 15,000
Present Worth: $14,097,000
Months to Implement: 48
Alternative 3B consists of the remedial action components identical
to those of Alternative 3A except for the final disposal of the
treated soil and storm sewer sediments. In Alternative 3B, after
the soil and storm sewer sediments are treated with the chemical
dechlorination process, they would be disposed onsite. In
accordance with Section 2.4.C.5 of the Virginia Solid Waste
Management Regulations (VSWMR), VR 672-20-10, backfilling of the
treated soil can only take place if the soil is treated to
background levels. If the soils cannot be treated to background
levels, disposal must be in either a RCRA Subtitle C landfill or a
solid waste landfill, depending on the operating guidance in effect
at the time of the disposal and in accordance with Part 8 of the
VSWMR. The remainder of the remedial action includes dechlorination
treatment of the sediments from the wastewater pond and the former
earthen separation pond with disposal in a RCRA Subtitle C facility,
scarification and solidification treatment of the concrete pads (if
determined to be a RCRA characteristic waste), and disposal as
directed by the VDWM, cleaning and demolition of the remainder of
the concrete pads and disposal offsite in a solid waste landfill,
and cleaning and sliplining the storm sewers.
Alternative 4A - Low Temperature Thermal Desorption with Offsite
Disposal
Capital Cost: $20,375,000
Annual O&M Cost: $ 15,000
Present Worth: $20,485,000
Months to Implement: 36
-21-
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Alternative 4A consists of onsite low temperature thermal desorption
of the contaminated soils and storm sewer sediments to meet the soil
cleanup level of 1.46 ppm of PCP, dechlorination of the sediments
from the vastewater pond and the former earthen separation pond,
offsite disposal of all of the treated soils and sediments in a RCRA
Subtitle C facility, backfilling of the area with clean soil,
scarification and solidification treatment of the concrete pads (if
determined to be a RCRA characteristic waste) with disposal as
directed by the VDWM, cleaning and demolition of the remainder of
the concrete pads with disposal offsite in a solid waste landfill,
and cleaning and sliplining of the storm sewers.
The low temperature thermal desorption unit would be a fully mobile
system. The contaminated soils and sediments would be fed into a
thermal processor or materials dryer where they would be heated to
400° F to 800° F and mixed and agitated, allowing moisture and
volatiles such as PCP to escape from the soil. The processor or
dryer gases, containing volatile organic compounds and dust, would
be vented into a cyclone or baghouse system to remove the entrained
particulate material. The airstream would then be directed into a
condenser to condense the volatile organic compounds for subsequent
treatment using either a carbon adsorption unit or an afterburner.
The spent carbon would be regenerated at an offsite facility at
which the organic contaminants would be destroyed by incineration.
Treat ability tests would have to be done during the design phase to
determine proper operating parameters. LDRs would not apply to the
soils and storm sewer sediments since these are not restricted
wastes under RCRA.
The remainder of the remedial action would be identical to that
under Alternative 3A, including treating the sediments from the
wastewater pond and the former separation pond with the
dechlorination process and disposing of these in a RCRA Subtitle C
facility, scarification and treatment, if necessary, of the concrete
pads and disposal offsite in a solid waste landfill, and cleaning
and sliplining the storm sewers.
Alternative 4B - Low Temperature Thermal Desorption with Onsite
Disposal
Capital Cost: $8,528,000
Annual O&M Cost: $ 15,000
Present Worth: $8,648,000
Months to Implement: 48
Alternative 4B consists of the remedial action components identical
to those of Alternative 4A except for the final disposal of the
treated soil and storm sewer sediments. In Alternative 4B, after
the soil and storm sewer sediments are treated with the low
temperature thermal desorption process, they would be disposed
onsite. The remainder of the remedial action would be identical to
that under Alternative 3A, including dechlorination treatment of the
sediments from the wastewater pond and the former separation pond
with disposal in a RCRA Subtitle C facility, scarification and
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solidification treatment of the concrete pads (if determined to be
a RCRA characteristic waste) and disposal as directed by the VDWM,
cleaning and demolition of the remainder of the concrete pads and
disposal offsite in a solid waste landfill, and cleaning and
sliplining the storm sewers. In accordance with Section 2.4.C.5 of
the VSWMR, VR 672-20-10, backfilling of the treated soil can only
take place if the soil is treated to background levels. If the
soils cannot be treated to background levels, disposal must be in
either a RCRA Subtitle C landfill or a solid waste landfill,
depending on the operating guidance in effect at the time of the
disposal and in accordance with Part 8 of the VSWMR.
Alternative S - In-Situ Vitrification
Capital Cost: $15,834,000
Annual O&M Cost: $ 14,000
Present Worth: $15,945,000
Months to Implement: 24
Alternative 5 consists of in-situ vitrification of all of the
contaminated soils and sediments, scarification and solidification
treatment of the concrete pads (if determined to be a RCRA
characteristic waste), and disposal as directed by the VDWM,
cleaning and demolition of the remainder of the concrete pads and
disposal offsite in a solid waste landfill, and cleaning and
sliplining the storm sewers.
The in-situ vitrification treatment process uses high voltage
electricity to melt the soils at the Site to form an inert glass
product. The shallow contaminated soils would have to be
consolidated in the area of deep contamination because this process
is not recommended for depths of less than 7 feet. Additionally, a
one to two foot layer of clean fill would have to be placed over the
area to be treated to minimize volatilization of the contaminants at
the surface during the treatment process. Once the desired melt had
been achieved, the electricity would be turned off and clean fill
would be used to fill the subsidence in volume resulting from the
loss of soil void volume (approximately 20% to 40%). The molten
mass would cool in place, resulting in a chemically inert, stable
glass residual product. Treatability tests would have to be done
during the design phase to determine proper operating parameters.
Because the soils and sediments would be consolidated in the same
area of contamination and the treatment would be done in-situ,
placement would not occur. Therefore, the LDRs under RCRA are not
an ARAR.
H. SmRjiflry of Comparative Analysis of Alternatives
All of the seven 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.
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THRESHOLD CRITERIA
1. Overall protection of human health and the environment; and
2. Compliance with applicable or relevant and appropriate
requirements (ARARs).
PRIMARY BAT-AMCTNG 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 Htyffi«fl pea1th 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.
Alternatives 3A, 3B, 4A, 4B, and 5 are all equally protective of
human health and the environment. These alternatives achieve this
protection by eliminating the contamination onsite through treatment
of the soils, sediments, and existing ground water. Alternative 2
provides adequate protection of human health and the environment by
controlling the risks posed by the exposure pathways through capping
the soils and sediments and by treating the ground water.
Additionally, in Alternatives 2 through 5, long-term ground water
monitoring and institutional controls are coupled to ensure that the
alternatives remain protective by monitoring ground water
contaminant concentrations at the boundary of the plume,
implementing deed restrictions to prevent utilization of either the
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Columbia aquifer or the Yorktown aquifer as a source of ground
water, and restricting the extraction of offsite ground water to
prevent further migration of the PCP. If ground water sampling
results were to indicate concentrations of PCP greater than 1 /ig/1
at the boundary of the plume, verification sampling would be
conducted, and perhaps active ground water restoration may be
implemented.
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 nine 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. 300.430(f)(1)(ii)(C).
Alternatives 3A, 4A, and 5 would meet all of the respective ARARs of
Federal and Virginia law (see Table 4). The treated soil and storm
sewer sediments in Alternatives 3A and 4A must meet the treatment
standards of C.F.R. Part 268 prior to land disposal in a RCRA
permitted facility. The level of treatment will determine whether
disposal must be in a Subtitle C facility or in a solid waste
facility, as determined by the VDWM. Although published data
indicate that the treatment processes for dioxin will meet the VSWMR
requirements, treatability studies will be performed during the
design phase to determine the residual contaminant levels for the
Site-specific soils and sediments. The treatment of the ground
water from the dewatering of the excavated soils and the
condensation from the low temperature thermal desorption process (if
using carbon adsorption) would be treated to meet the substantive
requirements of a VPDES permit to be established by the Virginia
State Water Control Board.
Because the treatment process for Alternative 5 is in-situ and does
not require any disposal of soil or sediments but only consolidation
within the same area of contamination, the VSWMR requirements
indicated above are not an ARAR. However, treatability tests will
also have to be performed for Alternative 5 during the design phase
to determine that the in-situ vitrification treatment process will
successfully destroy the organic contaminants and bind the inorganic
contaminants to meet the TCLP requirements.
Alternatives 3B and 4B would require treatment to background
conditions in accordance with the VHWMR and the VSWMR to allow
backfilling of the treated soil and storm sewer sediments onsite.
For Alternatives 3A, 3B, 4A, 4B, and 5, the concrete pads must be
tested by the TCLP to determine if the pads are a characteristic
-25-
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Standards,
Requirements,
Criteria, or
Limitations
Resource
Conservation and
Recovery Act
(RCRA)
Regulations
RCRA Regulations
Clean Hater Act
(CHA)
Regulations
Citation
40 C.F.R.
Section 268
(Subpart D)
40 C.F.R.
Section 268
(Subpart D)
40 C.F.R.
Section
122.44(a)
TABLE 4
ARARS
ACTION-SPECIFIC
Description
Land Disposal
Restrictions for
offsite disposal of
scarified waste from
concrete pads, if RCRA
Characteristic waste.
Land Disposal
Restrictions for
onsite consolidation
of contaminated soil.
Discharge of ground
water treatment system
effluent to Chuckatuck
Creek.
Applicable/
Relevant and
Appropriate
yes/no
no/yes
yes/no
Discussion
Alternatives 2-5.
Alternative 5. Soil
must be consolidated if
depth is less than 7
feet.
Alternatives 2, 3A, 3B,
4A, and 4B. Best
available technology
economically achievable
and best conventional
pollution control
technology required to
control toxic and
nonconventiona1
pollutants and
conventional pollutants,
respectively.
-------
CWA Regulations
CHA Regulations
40 C.P.R.
Sections
125.100,
125.104,
122.41(1),
136.1-136.4
40 C.P.R.
Section 122.44
Virginia Water
Quality
Standards
Virginia
Regulation
680-21-03.2
Virginia Permit
Regulation
VR 680-14-01
Permit
Regulation
Section 2.5
TABLE 4
ARARs
ACTION-SPECIFIC
Best Management yes/no
Practices for
discharge of ground
water treatment system
effluent to Chuckatuck
Creek.
Ambient Hater Quality yes/no
Standards for
discharge of ground
water treatment system
effluent to Chuckatuck
Creek.
State Water Quality yes/no
Criteria for surface
water serve as a
source for the
establishment of
discharge limits of
ground water treatment
system to Chuckatuck
Creek.
Virginia State Water yes/no
Control Board
establishes effluent
limitations on a case-
by-case basis.
Alternatives 2, 3, 3A,
4A, and 4B. Best
Management Practice
Program to prevent the
release of toxic
constitutents to surface
waters.
Alternatives 2, 3A, 3B,
4A, and 4B.
Alternatives 2, 3A, 3B,
4A, and 4B.
Alternatives 2, 3A, 3B,
4A, and 4B.
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TABLE 4
Virginia Toxics
Management
Regulation
VR 680-14-03
Virginia Erosion
and Sediment
Control Law
Virginia
Hazardous Haste
Management
Regulations
(VHWMR)
VR 672-10-1
VHWMR
VHWMR
VHWMR
Toxic*
Management
Regulation
Section 2
Virginia Code
Sections 10.1*
560 et seq.
VHWMR Part 3
VHWMR Section
10.5.H
VHWMR Part 10
VHWMR Parts 3
and 10
ARARs
ACTION-SPECIFIC
Requirements for yes/no
effluent discharge and
receiving stream
monitoring.
Methods to control yes/no
erosion and
sedimentation.
Hazardous Waste yes/no
determination
requirements.
Ground water no/yes
monitoring
requirements.
Onsite stockpiling or yes/no
staging of treated
soil.
Treatment, storage, yes/no
and disposal of spent
carbon from the ground
water treatment
system.
Alternatives 2, 3A, 3B,
4A, and 4B.
Alternatives 1, 2, 3A,
3B, 4A, 4B, and 5.
Alternatives 2-5.
Concrete pads will
undergo TCLP to
determine if RCRA
characteristic waste.
Alternatives 1, 2, 3A,
3B, 4A, 4B, and 5.
Alternatives 3A, 3B, 4A,
and 4B.
Alternatives 2, 3A, 3B,
4A, and 4B.
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VHWMR
VHHMR Part 7
VHWMR
VHWMR Part 3
Virginia Solid
Naste Management
Regulations
(VSWMR)
VR 672-20-10
VSWMR Part 8
TABLE 4
ARARS
ACTION-SPECIFIC
Transportation of the yes/no
treated soil and
sediments and the
spent carbon to an
offsite facility.
Treated soil and yes/no
sediments must meet
standards in order to
no longer be managed
as a hazardous waste.
Treated soil and yes/no
sediments must meet
requirements prior to
disposal in a solid
waste landfill in
Virginia.
Alternatives 3A and 4A
for the treated soil and
all sediments and the
spent carbon.
Alternatives 3B and 4B
for the treated K001
sediments and spent
carbon.
Alternatives 3A and 4A
for the treated soil and
storm sewer sediments.
Alternatives 3A and 4A
for the treated soil and
storm sewer sediments.
-------
Standards,
Requireaents,
Criteria, or
Limitations
Safe Drinking
Water Act (SOWA)
Regulations
Virginia Hater
Quality
Standards
Citation
40 C.F.R.
Section 141.11
Virginia
Regulations
680-21-03.2
TABLE 4
ARARs
CHEMICAL-SPECIFIC
Description
Maximum Contaminant
Level for discharge of
ground vater treatment
system to Chuckatuck
Creek.
Site specific Halts
for discharge of
treatment systea
effluent to Chuckatuck
Creek.
Applicable/
Relevant and
Appropriate
yes/no
yes/no
Discussion
Alternatives 2, 3A, 3B,
4A and 4B.
Alternatives 2, 3A, 3B,
4A and 4B.
-------
Standards,
Requirements,
Criteria, or
Limitations
Citation
TABLE 4
ARARs
LOCATION-SPECIFIC
Description
Applicable/
Relevant and
Appropriate
Discussion
National
Historic
Preservation Act
Virginia
Endangered
Species Act
16 U.8.C.
Section 470
et sea.
Virginia Code
Section
29.1-563
et sea.
Phase 1 archaelogical yes/no
field survey to locate
all archaelogical
resources that may be
impacted.
Conduct biological yes/no
Assessment to
determine if the
Dismal Swamp
Southeastern Shrew or
its habitat is present
on the Site.
Alternatives 1, 2, 3A,
3B, 4A, 4B and 5.
Alternatives 1, 2, 3A,
3B, 4A, 4B and 5.
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waste and if scarification and treatment are required. If the pads
are determined to be a RCRA hazardous characteristic waste, they
must be scarified to remove the top one inch and the removed
material solidified. If the solidified material passes TCLP, the
waste will be considered a special waste under VSWMR Part 8 and
disposal will then be as directed by the VDWM. The remaining
concrete debris would then be cleaned of any residual soil and
disposed offsite in a solid waste landfill.
Since Alternative 2 includes capping the soils, the only VHWMR
requirement that would be an ARAR is Section 10.5.H. The discharge
of treated ground water would have to comply with the substantive
requirements of a VPDES permit to be established by the Virginia
State Water Control Board in accordance with VR 680-14-01.
Alternatives 2 through 5 must comply with the requirements of the
National Historic Preservation Act, 16 U.S.C. Section 470 et seq..
which has been determined to be an ARAR for this Site. Due to the
archaeological potential of the Site, as well as the project
impacts, a Phase 1 archaeological field survey would be necessary
during the design phase. The purpose of the survey is to locate all
archaeological resources which may be impacted by the remedial
action.
Alternatives 2 through 5 must also comply with the requirements of
the Endangered Species Act because of the possible existence of the
Dismal Swamp Southeastern Shrew on the Site. A biological
assessment would be required to determine it the shrew or the
shrew's habitat is present on or in close proximity to the Site. If
so, appropriate mitigating measures would be determined and required
such that the shrew and/or its critical habitat would not be
affected by the remedial activities.
3. Lone-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.
Alternative 4A, the selected alternative, and Alternative 3A provide
the greatest degree of long-term effectiveness and permanence
because they provide for treatment and offsite disposal of all of
the soil and sediments.
Alternatives 3B and 4B differ only in the final disposal of the soil
and storm sewer sediments. In Alternatives 3B and 4B, the treated
soil and storm sewer sediments would be disposed onsite if they can
be treated to background levels. Because the sediments from the
wastewater pond and the former earthen separation pond are KOOl
listed hazardous wastes, they must be disposed in a RCRA Subtitle C
facility.
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For Alternatives 3A, 3B, 4A, and 4B, further degradation of the
Yorktown aquifer is curtailed by plugging the preexisting wells and
by substantial removal and treatment of the contaminated ground
water in the Columbia aquifer during the devatering process required
for the excavation of the soils. However, levels of PCP which do
not pose a direct contact risk (i.e. greater than 1.46 ppm) would
remain in the soil. These levels may result in PCP concentrations
above 1 ppb partitioning into the Columbia aquifer. Therefore,
monitoring of the Columbia and Yorktown aquifers would be required
to assure that the remedial cleanup goal of 1 ppb is not exceeded at
the boundary of the plume.
For Alternative 5, treatability testing would be required to assess
the effectiveness of the in-situ vitrification. Although the in-
situ vitrification has the potential to eliminate the exposure risks
associated with the contaminated soils and sediments, treatability
tests would be required to assess the magnitude of residual risks.
The contaminated ground water in the Columbia aquifer would be
removed (evaporated) during treatment. However, any PCP remaining
in the untreated soils may cause PCP concentrations greater than l
ppb partitioning into the Columbia. As such, ground water
monitoring would be required to assure that the remedial cleanup
goals are not exceeded.
For Alternative 2, the risks posed by soil contaminants through the
potential exposure pathways would be eliminated only as long as the
cap was properly maintained. Alternative 2 therefore offers the
least long-term protectiveness. Because the source is only
contained, long-term threats remain should the remedy fail. Ground
water within the boundaries of the Site would have concentrations of
PCP greater than the proposed MCL of 1 ppb. However, this would
pose little risk to human health. The ground water within the site
could not be used for domestic purposes since institutional controls
would be implemented as part of the remedy to restrict the use of
ground water onsite and to preclude development of the Site in order
to protect the integrity of the cap. The 1 ppb proposed MCL for PCP
would be attained at the boundary of the plume by extraction of the
contaminated ground water from the Columbia aquifer via subsurface
drains, and through dispersion by natural flow conditions in the
Yorktown aquifer.
4. Reduction of Toxicity. 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
-27-
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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 3A, 3B,
4A, 4B, and 5 would all reduce the toxicity of the Site contaminants
by removing and/or destroying the organic contaminants. However,
for all of these alternatives, the actual effectiveness of the
different technologies would have to be confirmed by treatability
testing performed during the design phase.
The in-situ vitrification under Alternative 5 would destroy the
organic contaminants and immobilize the inorganic contaminants in
the soil and sediments. The PCP in the contaminated ground water
within the Columbia would be substantially removed by evaporation
during the treatment process. The PCP would be captured during this
process and destroyed in a separate process.
In Alternatives 4A and 4B, chemical dechlorination treatment would
reduce the toxicity of the K001 sediments by permanently destroying
the PCP and dioxin contaminants. The PCP contamination in the soil
and storm sewer sediments would be transferred from the soil phase
to the air phase using the low temperature thermal desorption
process. The organic-laden air would be treated by either catalytic
or thermal oxidation or carbon adsorption. Oxidation would result
in immediate contaminant destruction, while carbon adsorption would
lead to destruction when the carbon is regenerated. The optimum
operating temperature for the removal of PCP may cause the arsenic
present in the soil to volatilize. If so, the soils would first be
treated with lime to convert the arsenic to a less volatile form of
arsenic, thus reducing the mobility of the arsenic. During the
dewatering of the soils, the PCP contamination in the ground water
in the Columbia aquifer would be reduced using carbon adsorption.
The PCP would then be destroyed when the carbon is regenerated.
Removing and plugging the preexisting wells will reduce the mobility
of the PCP remaining in the soil from reaching the Yorktown aquifer.
In Alternatives 3A and 3B, chemical dechlorination treatment would
reduce the toxicity of the contaminated soil and sediments by
permanently destroying the PCP and dioxin contaminants. During the
dewatering of the soils, the PCP contamination in the ground water
in the Columbia aquifer would be reduced using carbon adsorption.
The PCP would then be destroyed when the carbon is regenerated.
Removing and plugging the preexisting wells will reduce the mobility
of the PCP remaining in the soil froa reaching the Yorktown aquifer.
Alternative 2 would not reduce the toxicity, mobility or volume of
the contaminated soils or sediments since only ground water would be
treated. The PCP contamination in the ground water in the Columbia
aquifer would be reduced using carbon adsorption. The PCP would
then be destroyed when the carbon is regenerated. Removing and
plugging the preexisting wells will reduce the mobility of the PCP
remaining in the soil from reaching the Yorktown aquifer.
-28-
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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 for long-term
ground water monitoring, which will be required for all of the
remaining alternatives. All of the timeframes listed below are
estimates.
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 the capping and excavation of the
drainage trenches 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. Grading of the Site
would result in minimal soil disturbance.
It is estimated that Alternative 5 would take approximately 2 years
to implement. Excavation of soils would be more extensive than that
under Alternative 2 because of the need to consolidate the shallow
soils to a depth of at least 7 feet. It is estimated this would
entail the excavation and handling of approximately 7,200 cubic
yards of contaminated soil. In addition, the concrete pads and some
building structures would require removal. The structures would
have to be removed because the in-situ vitrification will cause a
20% to 40% subsidence in soil volume, resulting from the loss of
soil void volume.
Alternative 4A ia expected to take approximately 3 years to
implement. In addition to the removal of the concrete pads, the
amount of soil and sediment excavation required would be much more
extensive than Alternatives 2 and 5. As such, the amounts of dust
production, noise disturbance, and truck traffic would also be
significantly increased. However, dust-suppression techniques could
substantially control any dust that would be generated to protect
the workers at the Site and the residents in the area of the Site.
Although Alternative 4B is expected to take approximately 4 years to
implement, it would entail less truck traffic than Alternative 4A
because there would not be the offsite disposal of the treated soil
and storm sewer sediments, which make up the bulk of the material to
be disposed offsite.
Alternative 3A is expected to take approximately 3 years to
implement. The short-term effects associated with this alternative
would be similar to those indicated for Alternative 4A:
significantly increased dust production, noise disturbance, and
truck traffic. As with Alternative 4A, dust-suppression techniques
could substantially control any dust that would be generated to
-29-
-------
protect the workers at the Site and the residents in the area of the
Site.
Alternative 3B is expected to take approximately 4 years to
implement. As the case with Alternative 4B, the truck traffic would
be less than that associated with Alternatives 3A and 4A because
there will be less material to be disposed offsite.
6. Impleroentability
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.
Alternatives 2, 3A, and 4A could be easily implemented. Operation
of either the chemical dechlorination system under Alternative 3A or
the low temperature thermal desorption and chemical dechlorination
systems under Alternative 4A would be fairly straightforward once
treatability tests are completed and the systems' operating
parameters are established. The handling, treatment, and disposal
of the 25,000 tons of contaminated soils and sediments would require
a design plan sequencing remedial activities to facilitate an
efficient removal. In addition, varying volumes or concentrations
of soils or sediments could be easily handled and ground water
treatment could be easily implemented, if required.
The cap and ground water extraction and treatment systems under
Alternative 2 are both simple to construct and operate. Although
the cap could be easily extended or repaired, if needed, it would
preclude direct soil treatment unless it were removed.
Alternative 5 would require special equipment and trained personnel.
Although the in-situ vitrification could accommodate varying volumes
of contamination, it may be difficult to implement future remedial
actions if the vitrified material was not protective of human health
and the environment.
Operation of Alternatives 3B and 4B would be the same as that for
Alternatives 3A and 4A. However, since the treatment systems are
not currently expected to reduce the contaminants to background
levels as required by the onsite disposal provisions of Part 8 of
the VSWMR, these two alternatives are not considered implementable.
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.
-30-
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Alternative 2 has the lowest present worth cost, $3,459,000. Of the
alternatives that include treatment of the contaminated soil and
sediments, Alternative 4B has the lowest present worth cost,
$8,648,000. Alternatives 3B and 5 have the next lowest present
worth costs at $14,097,000 and $15,945,000, respectively. Of the
alternatives that include offsite disposal of the treated soil and
sediments, the selected alternative, Alternative 4A, has the lowest
present worth cost, $20,485,000. Alternative 3A has the highest
present worth cost of all of the alternatives, $25,934,000. The
present worth costs for Alternatives 3A and 4A include the cost of
offsite disposal in a RCRA Subtitle C facility. If it is later
determined that disposal may take place in a solid waste facility,
the present worth costs for these two alternatives will be reduced
accordingly. It is estimated at this time that the cost reduction
would be approximately $6,250,000. A breakdown of the cost of
Alternative 4A is provided in Table 5.
8. State Acceptance
The Commonwealth of Virginia has concurred with the remedy selected
in this Record of Decision.
9. Community Acceptance
On June 4, 1991, a public meeting was held at the Oakland Elementary
School in Suffolk, Virginia to discuss EPA's preferred alternative
as described in the Proposed Plan. A public comment period for the
Proposed Plan was held from May 23, 1991, through July 22, 1991.
The comment period was extended as requested by the Saunders Supply
Company. 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 Alternative 4A 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, Alternative 4A represents the
best balance among the evaluation criteria.
Performance standards
The selected remedy addresses all of the contaminated media at the
Site and consists primarily of the following: excavation,
dechlorination treatment, and offsite disposal of the KOOl
sediments; excavation, low temperature thermal desorption, and
offsite disposal of the contaminated soil and storm sewer sediments;
scarification and solidification treatment of the top one inch of
the concrete pads (if determined to be a RCRA characteristic waste)
and offsite disposal of the treated material as directed by the
VDWM; cleaning and offsite disposal of the remainder of the concrete
pads; cleaning and sliplining of the storm sewer; implementation of
institutional controls; and ground water monitoring. By instituting
-31-
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TabtoS
CAPITAL COSTS ALTERNATIVE 4A
REMEDIAL ALTUtNAllVE ITEM
SURVEYINO
SITE PREP. /CLEARING t GRUBBING
STRUCTURE REMOVAL/REPAIR
DECOH PAD
UTILITY HOOKUP
SOIL
STAOING/STORAfiE AREAS
TREATABILITY STUDY
LOW-TEMP. THERMAL DESORPTION
TREATMENT EQUIPMENT PAD
EXCAVATION
0 - 2"
0-1-
0-2'
0 - CLAY
DUST CONTROL
TREAT WATER FROM SOIL «WATSR.
EXCAV. VERIFICATION SAMPLING
TREAT. VERIFICATION SAMPLING
OFT-SITE DISPOSAL AT RCRA
FACILITY
TRANSPORT TO RCRA FACILITY
BACKFILL SZTE WITH CLEAR FILL
0 - J"
0-1'
0-2'
0 - OJCT
SITE RESTOXATIOa
STOXH SENEX SEDIMEMT
STORM SEWER CLEAHIWS
FLUSR WATER TREAJKEWT
DISPOSAL OP WATER t POTN
TRAUPORI WATER TO POTW
UNITS
LS
LS
LS
LS
LS
LS
LS
TOM
LS
MSF
MSF
at
Of
LS
GAL
LS
LS
TOR
TOB
MSP
MSP
cr
or
LS
LP
GAL
GAL
OAL
UNIT COST QUANTITY
$3,000.00
$3,000.00
$5,000.00
$2,500.00
$10,000.00
$15,000.00
$20,000.00
$175.00
$750.00
$110.00
$220.00
$6.50
$20.00
$20,000.00
$0.30
$65,000.00
$60,000.00
$210.00
$41.50
$215.00
$•00.00
$13.00
$13.00
$3,000.00
$10.00
$0.30
$0.20
$0.05
1
1
1
1
1
1
1
25000
1
62
167
620
11550
1
350000
1
1
25000
25000
62
167
620
12200
1
550
5000
5000
5000
TOTAL
CAP. COST
$3.000
$3,000
$5,000
$2,500
$10,000
$15,000
$20,000
$4,375.000
$750
$9,020
$36,740
$4,030
$231,000
$20,000
$105,000
$65,000
$60,000
$7,000,000
$1,212,500
$23,370
$133,600
$6,060
$156,600
$3.000
$5,500
$1,500
$1,000
$250
THERMAL DESORPTIOM
I INCLUDED ABOVE )
K001
STMnQ/STORAOE AHA
SEPARATION PO«D
VERIFICATION 1AMPLINO
TREATABXUTY STUDY
^HJBdCAt DCCHUQ1I21IARQH
RCAOENT DISPOSAL
LOAD TANKER TRUCK
TRANSPORTATION
INCINERATION
OFT-SITE DISPOSAL AT RCRA
FACILITY
TRANSPORT TO RCRA FACILITY
LS
CY
CY
LS
TOM
EA
MI
LB
TON
TON
$5,000.00
$20.00
$20.00
$20,000.00
$325.00
$«t.OO
$5.00
$1.00
$210.00
$46.50
450
115
1
700
1
1000
20000
700
700
$5.000
$9.000
$2.300
$20,000
$227,500
$8»
$5,000
$20.000
$196,000
$33.950
-------
TabtoS(Cont)
SURFACE HATER
DRAIN WW POND HATER LS $500.00 1 $500
W POND HATER TREATMENT GAL $0.30 7200 $2,160
DISPOSAL Or WATER 9 POTW GAL $0.20 7200 $1.440
TRANSPORT HATER TO POTW GAL $0.05 7200 $360
BACKFILL POND ARIA CT $13.00 1300 $16,900
CONCRETE PADS
SCARIFICATION SF $2.25 16850 $37,913
CONOim TCLP EA $310.00 2 $620
SOLIDIFICATION I OFF-SITE
DISPOSAL AT ROtA FACILITY TON $280.00 100 $28,000
TRANSPORT TO RCXA FACILITY TON $41.50 100 $4.850
CONOUTTE PAD DEMOLITION SF $3.79 260 $975
DISPOSAL AT OFF-SITE SOLID
HASTE FACILITY TON $8.00 500 $4.000
TRANSPORT TO SOLID WkSTE
FACILITY TON $7.50 500 $3,750
LIMITED ACTION t
INSTITUTIONAL CONTROLS $0
INSTALL NEW WBLLS LS $14,000.00 1 $14.000
PLUS WELLS EA $4,500.00 6 $27,000
SUBTOTAL $14,173,726
(25%) $3.543,431
$17,717,157
$2,657,574
TOTAL COST $20,374,730
-------
all of these components, the Site risks would be reduced to within
the EPA acceptable risk range. The major components of this
alternative include the following:
• To reduce the risk to human health and the environment via
the exposure pathways attributed to the K001 sediments,
approximately 700 tons of sediments from the wastewater pond
and the former earthen separation pond will be excavated and
treated by the dechlorination process. Since the sediments
contain RCRA K001 listed hazardous waste, the sediments must be
disposed offsite in a RCRA Subtitle C facility. The excavated
areas will be filled with clean soil and contoured to promote
run-off.
• To reduce the risk to human health and the environment via
the exposure pathways attributed to the contaminated soil and
storm sewer sediments, approximately 24,300 tons of surface and
subsurface soils exceeding the soil cleanup level of 1.46 mg/kg
of PCP (corresponding to a 10~6 risk level) and the sediments
from the storm sewer along Godwin Boulevard will be excavated,
treated by the low temperature thermal desorption process, and
disposed offsite in accordance with the operating guidance in
effect at the time of disposal.
• To reduce the risk to human health and the environment via
the exposure pathways attributed to the water in the wastewater
pond, the pond will be drained and the water treated prior to
discharge. It will be determined during the design phase
whether to treat the water onsite and discharge to Chuckatuck
Creek or to treat and discharge offsite. If treating onsite,
the discharge to Chuckatuck Creek will meet VPDES permit
limits. If treating and discharging offsite, the treatment
will meet the levels as set by the receiving facility.
• To reduce the risk to human health and the environment
attributed to the concrete pads, the concrete pads will be
tested to determine if they are a RCRA characteristic hazardous
waste, especially for arsenic and chromium, using the TCLP. If
the pads are determined to be a RCRA characteristic waste,
approximately the top one inch of the pads will be scarified,
solidified, and disposed offsite in a landfill as directed by
Part 8 of the VSWMR. During the scarification process, the
following dust control techniques will be implemented to
control the possible release of contaminated material: pre-
wetting the concrete, equipping the scabbier with a sprayer,
and using a vacuum attachment for dust collection. The
remainder of the concrete pads will be cleaned of any residual
soil and disposed in a solid waste facility. If the pads are
not determined to be a characteristic waste, the entire pad
will be cleaned of any residual soil and disposed in a solid
waste facility.
• To reduce the risk to human health and the environment
attributed by the existing 8 inch concrete storm sewers, the
-32-
-------
sewers will be inspected, cleaned and sliplined. The storm
sewer will first be inspected with a closed circuit television
camera to identify any obstructions and then thoroughly
cleaned. The material cleaned out of the sewer will be
collected, treated using the low temperature thermal desorption
process, and then disposed offsite. After the sewers are
cleaned, they will be sliplined with a flexible high-density
polyethylene pipe of a slightly smaller diameter. The service
connections will then be reconnected to the new liner. The
annulus between the old and the new pipeline may be filled with
grout.
• To reduce the risk to human health and the environment
attributed to the movement of PCP from the Columbia aquifer to
the Yorktown aquifer, the preexisting wells that are screened
across the confining clay layer will be removed and plugged.
• To ascertain that the remedy is protective of human health
and the environment, long-term ground water monitoring will be
performed for thirty years. The ground water monitoring will
include sampling for PCP, arsenic, and chromium as they were
the only contaminants associated with the operations at the
Site which were detected at elevated levels in the ground
water. EPA will determine the appropriate number and location
of the monitoring wells during the design phase. The
monitoring will determine if the cleanup level of 1 ppb of PCP,
the proposed MCL, is being met at the boundary of the plume in
both the Columbia aquifer and the Yorktown aquifer.
• To restrict access to the contaminated ground water under the
Site and to prevent accelerated movement of the PCP offsite,
institutional controls will be implemented. The institutional
controls include deed restrictions on the Site to prohibit
using either the Columbia aquifer or the Yorktown aquifer as a
source of ground water and restrictions on offsite ground water
extraction.
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.
However, it may also include changing the disposal of the treated
soil and storm sever sediments to a solid waste facility, as allowed
by the VDWM. The estimated present worth cost of the selected
remedy is $20,485,000. The present worth cost is comprised of a
capital cost of $20,375,000 and an annual operation and maintenance
cost of $15,000. Details of the costs for the selected remedy are
shown in Tables 5 and 6.
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
-33-
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Tables
CAPITAL COSTS ALTERNATIVE 4A
REMEDIAL AUouwriVE ITOt
SURVEYING
SITE PREP. /CLEARING t GRUBBING
STRUCTURE REMOVAL/REPAIR
DECOR PAD
UTILITY HOOKUP
SOIL
STAGING/STORAGE AREAS
TREATABILITY STUDY
LOW-TEMP. THERMAL DESORPTIOH
TREATMENT EQUIPMENT PAD
EXCAVATIOR
0-2"
0-1'
0-2"
0 - OAT
OUST CONTROL
TREAT WATER FROM SOIL DEMATER.
EXCAV. VERIFICATION SAMPLIM
TREAT. VERIPICATXOH SAMPLING
OPP-Sm DISPOSAL AT RCRA
PACIUTT
TRANSPORT TO RCRA PACXLXTT
BACKFILL SITE WITH CLEAR PILL
0-2-
0-1'
0-2'
0 - CLAX
SITE RESTORAnOH
61URH SENCR SCDUOffT
STORM SENER OiAHIWO
FLUSH WtTER TRCAXMEIR
DISPOSAL OP WOn f POTW
TRABSPORT WATER TO POTW
LOW-TEMP. THERMAL DESORPTIOH
( HKLUDED ABOVE )
UNITS
LS
LS
LS
LS
LS
LS
LS
TOR
LS
Hsr
MSP
or
or
LS
GAL
LS
LS
TOR
TOR
MSP
MSP
CT
CI
LS
LF
(SAL
GAL
GAL
UNIT COST QUANTITY
$3,000.00
$3,000.00
$5,000.00
$2,500.00
$10,000.00
$15,000.00
$20,000.00
$175.00
$750.00
$110.00
$220.00
$6.50
$20.00
$20,000.00
$0.30
$65,000.00
$60,000.00
$210.00
$41.50
$2(5.00
$800.00
$13.00
$13.00
$3,000.00
$10.00
$0.30
$0.20
$0.05
1
1
1
1
1
1
1
25000
1
82
167
620
11530
1
350000
1
1
25000
25000
82
167
620
12200
1
550
5000
5000
5000
TOTAL
CAP. COST
$3,000
$3,000
$5,000
$2,500
$10,000
$15,000
$20,000
$4,375,000
$750
$9,020
$36,740
$4.030
$231,000
$20,000
$105,000
$65.000
$60,000
$7,000,000
$1,212.500
$23.370
$133,600
$8,060
$158,600
$3,000
$5,500
SI. 500
$1,000
$250
KOOI
EKAVXriOR
VERIFICATION SARPLXRO
TRCATABIUTr STUDT
CHEMICAL DECKLORXRATXOR
REAGENT DISPOSAL
LOAD TANKER TRUCK
TRARSPORTATIOR
IRCIRERATXOR
OFF-SITE DISPOSAL AT RCRA
FACILITY
TRANSPORT TO RCRA FACILITY
CT
CT
LS
EA
MI
LS
TOR
TOR
$5,000.00
$20.00
$20.00
$20.000.00
$325.00
$88.00
$5.00
$1.00
$280.00
$48.50
450
115
1
700
1
1000
20000
700
700
$5,000
$9,000
$2,300
$20.000
$227,500
$88
$5,000
$20,000
$196,000
$33.950
-------
TabtoS(Cont)
SURFACE KKTCR
DRAIN WW tam HATER LS $500.00 1 $500
WW FOWD HATE* THEATKEWT GAL $0.30 7200 $2,160
DISPOSAL OF HATER 9 POTM GAL $0.20 7200 $1.440
•TRANSPORT WATER TO POTW GAL $o.os 1200 $360
BACKFILL POND AR£A CY $13.00 1300 $16,900
CUIKKllL PADS
SCARIFICATION sr $2.25 16850 $37.913
oonomc TO* CA $310.00 2 $620
SOLIDirlCATIOH t OFF-SITE
DISPOSAL AT RCXA FACILITY TOH $280.00 100 $28,000
TRANSPORT TO ftCRA FACILITY TOM $48.50 100 $4,850
Cum-Ht-U PAD DOCUTIOH SF $3.75 260 $975
DISPOSAL AT OFF-SRC SOLID
MASTE FACILITY TOH $8.00 500 $4,000
TRANSPORT TO SOLID HASTE
FACILITY TOM $7.50 ' 500 $3,750
LIMITED ACTION I
IRSTTTVriORAL COMTROLS $0
INSTALL NEW NELLS LS $14,000.00 1 $14,000
PLUO WELLS EA $4,500.00 6 $27,000
SUBTOTAL $14.173,726
OAKY (25%) $3,543,431
SUBTOTAL $17,717,157
(15%) $2,657,574
$20,374,730
-------
Tat* 6
omuaxoH MID wuNTDiwtcr COSTS rax Atrnuwrivt tx
RZHEDIAL ALTERHATIVE ITCH UNITS UIRT COST QUANTITY YEARS MOUM, COST
MMUM. SAKPLZm LS $11,000.00 - 24 ,$11,000
SAHPUflO EACH S TZARS LS $14,000.00 - 6 $14,000
-------
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 lavs, 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.
Hunan Health anc
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 1.
Excavation and treatment of the contaminated soil and sediments,
removal and disposal of the concrete pads, and sliplining the storm
sewer will assure the Site risks will fall within EPA's acceptable
risk range.
The selected remedy protects human health and the environment by:
1. Eliminating direct contact with the contaminant levels in
the surface and subsurface soils, the storm sewer
sediments, and the K001 sediments by excavating, treating
and disposing of these wastes in an approved offsite
facility;
2. Reducing contaminant levels in the concrete pads by
testing to determine whether they are a characteristic
hazardous waste, scarification and treatment of the top
one inch of the pads if they are a characteristic waste,
removal of any residual soil, and offsite disposal of the
remaining portion of the pads;
3. Eliminating direct contact with the water in the
wastewater pond by treating and discharging of the water
as determined during design; and
4. Reducing the contaminant levels in the existing concrete
storm sewer by cleaning and sliplining the sewer.
Of all of the alternatives evaluated, Alternative 4A 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.
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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 4.
Chemical-Specific ARARs: The selected remedy will achieve
compliance with chemical specific ARARs related to the concrete
pads. Specifically, the concrete pads will undergo a TCLP test to
determine if they are RCRA characteristic wastes in accordance with
40 C.F.R. Part 261.
Action-Specific ARARs: If the concrete pads are determined to be
RCRA characteristic wastes, the top one inch of the pads will be
scarified and that material will be solidified prior to disposal.
The remainder of the concrete pads will be cleaned of any residual
soil prior to disposal. The K001 sediments will be treated by the
dechlorination process prior to disposal in a RCRA Subtitle C
facility. The soil and storm sewer sediments will be treated by the
low temperature thermal desorption process prior to disposal. The
level of treatment will determine whether disposal must be in either
a RCRA Subtitle C landfill or a solid waste landfill, depending on
the operating guidance at the time of disposal and the requirements
of Part 8 of the VSWMR. Transportation to a RCRA-permitted
treatment and/or disposal facility would conform with RCRA
regulations at 40 C.F.R. Parts 262 and 263, the Department of
Transportation regulations of Title 49 of the Code of Federal
Regulations, and Part 7 of the VHWMR. The substantive requirements
of the Virginia Erosion and Sediment Control Law will be achieved.
Storage of soils in a waste pile must conform with Section 10.11 of
the VHWMR. Storage of the K001 wastes must conform with Sections
10.8 and 10.9 of the VHWMR. The substantive requirements of a VPDES
permit by the Virginia State Water Control Board must be complied
with for the discharge of treated ground water. All air emissions
from Site activities must conform with the Virginia Department of
Air Pollution Control Regulations for Control and Abatement of Air
Pollution.
Location-Specific ARARs: The National Historic Preservation Act is
an ARAR for this Sit*. Due to the archaeological potential of the
Site, as well as the possible project impacts, a Phase l
archaeological field survey would be completed during the design
phase. The purpose of the survey is to locate all archaeological
resources which may be impacted by the remedial action. The
Endangered Species Act is a potential ARAR due to the possible
existence of the Dismal Swamp Southeastern Shrew on the Site. As
such, a biological assessment must be conducted to determine if the
shrew or the shrew's habitat is present on or in close proximity to
the site. If so, mitigating measures would be required such that
the shrew or the shrew's critical habitat would not be adversely
affected by the remedial activities.
Other Criteria, Advisories or Guidance To Be Considered: Although
the Safe Drinking Water Act MCL for PCP is presently 200 nq/l, EPA
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has proposed a revised MCL of 1 Mg/1 to take effect in 1992. Since
the remedial action is not likely to be complete prior to the
effective date, EPA has decided to utilize the proposed value in
this ROD. Because the ground water in the Columbia aquifer and the
Yorktown aquifer has the characteristics of a Class II aquifer, the
ground water must not exceed 1 Mg/1 at the boundary of the plume.
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)(1)(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 $20,485,000.
Utilization of Permanent Solutions and Alternative Treatment
for Resource Recovery! Technologies to the Maximum Extent
Practicable fMEPl
EPA has determined that the selected remedy, Alternative 4A,
represents the maximum extent to which permanent solutions and
treatment technologies can be utilized in a cost-effective manner
for remediation of the Site. Of those alternatives that are
protective of human health and the environment and comply with
ARARs, EPA has determined that the selected remedy, Alternative 4A,
provides the best balance of trade-offs in terms of long-term
effectiveness and permanence, reduction in toxicity, mobility, or
volume through treatment, short-tern effectiveness,
implementability, and cost, while also considering the statutory
preference for treatment as a principal element and considering
state and community acceptance.
Alternative 4A was selected because it is protective of human health
and the environment, complies with all ARARs, has a higher degree of
long-term effectiveness and permanence, reduces the toxicity,
mobility or volume through treatment, and is easily implemented. By
treating all of the contaminated media at the Site to EPA acceptable
risk levels, Alternative 4A is protective of human health while also
reducing the toxicity of the contaminants through treatment.
Because the treated soil and sediments will be disposed offsite,
Alternative 4A meets all ARARs, including the VSWMR. Also, the
offsite disposal offers a higher level of long-term effectiveness
and permanence because at the risk-based soil cleanup level, PCP may
leach into the ground water at levels exceeding the ground water
cleanup level. Also, the treatment systems utilized under
Alternative 4A (dechlorination, low temperature thermal desorption,
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scarification, solidification and ground water treatment) could be
easily implemented.
Alternative 3A is equal to the selected alternative with regard to
being protective of human health and the environment, complying with
all ARARs, having a high degree of long-term effectiveness and
permanence, reducing toxicity, mobility or volume through treatment,
and being easily implemented. However, Alternative 3A is not as
cost-effective as the selected alternative. With a present worth
cost of $25,934,000, Alternative 3A would cost $4,449,000 more than
Alternative 4A. Since Alternatives 3A and 4 A have the same
effectiveness, the one with the lower cost, Alternative 4A, is more
cost-effective.
Although Alternative 5 has a lower present worth cost and meets all
ARARs, it does not have as much long-term effectiveness and
permanence as Alternatives 3A and 4A. Also, because of the nature
of the treatment process, it may not be as implementable as these
other alternatives.
Alternatives 3B and 4B were not selected because neither alternative
complies with all ARARs. Since both alternatives contain onsite
disposal of the treated soil and storm sewer sediments, the VSWMR is
not met for either alternative. Also, since the soil cleanup level
may allow PCP to leach into the ground water at levels exceeding the
ground water attainment level, Alternatives 3B and 4B do not provide
as much long-term effectiveness or permanence as the selected
alternative.
Alternative 2 was not selected because it does not fulfill the
statutory requirements to utilize treatment technologies to the
maximum extent practicable and the preference for treatment as a
principal element. In addition, it does not reduce the toxicity,
mobility or volume through treatment.
The Virginia Department of Waste Management has concurred with the
selected remedy.
Preference for Treatment as a Principal Element
The selected remedy satisfies the statutory preference for treatment
as a principal element. The PCP contamination in the soil
constitutes the major human health risk associated with the Site and
is considered a principal threat. The low temperature thermal
desorption treatment system will effectively remove the PCP from the
soil by heating it to 400° F to 800° F. The exhaust will then be
vented to a cyclone or baghouse unit to remove any entrained
particulate material. Next, the air will be directed into a
condenser where the PCP will be condensed for subsequent treatment
such as a carbon adsorption unit or an afterburner. The KOOl
sediments will be treated with the dechlorination process which will
effectively destroy all of the organic contaminants including PCP
and dioxin. The ground water recovered during the excavation and
dewatering of the soils and the water from the wastewater pond will
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also be treated. Finally/ if the concrete pads are determined to be
a RCRA characteristic hazardous waste, approximately the top one
inch of the pads will be scarified and solidified prior to disposal.
K. Documentation of Significant Changes
The Proposed Plan, which identified Alternative 4A as EPA's
preferred alternative for the Site, was released for public comment
on May 23, 1991. EPA reviewed all written and verbal comments
submitted during the public comment period and determined that no
significant change to the remedy identified in the Proposed Plan was
necessary.
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