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

-------
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

-------
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.

-------
                        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.

-------
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

-------
           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.

-------
Source: USGS T.S Mlnuw ScriM (Toooflrtpfttc) Qu*dr*nfto«: Chuckctuck, VlrglnM. H7«.

                                   SCALE
                                                    1 Mil*
                                              1 KUonwnr
                                  Figural
              SAUNDERS SUPPLY COMPANY LOCATION MAP

-------
         Figure 2
SAUNDERS SUPPLY COMPANY
      FACILITIES MAP

-------
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

                               -2-

-------
 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


                                -3-

-------
 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.

                               .4-

-------
              F)gure3
SURFACE WATER AND SEDIMENT SAUPLINi
   LOCATIONS WITHIN THE STUDY AREA

-------
             Hour* 4
SURFACE WATER AND SEDIMENT SAMPLING
    LOCATIONS ON AND ADJACENT TO
      THE SAUNDERS PROPERTY

-------
             Figure S
SUBSURFACE SOIL 8AUPUNO LOCATIONS

-------
    Flflurae
WELL LOCATIONS

-------
 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

                                -5-

-------
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

                               -6-

-------
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

-------
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

                                -7-

-------
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-

-------
    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-

-------
                            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-

-------
     • 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-

-------
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-

-------
                       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-

-------
                      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
-------
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:

                               -14-

-------
                     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%

-------
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)





-------
 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-

-------
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-

-------
 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.


                               -17-

-------
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-

-------
 (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-

-------
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-

                               -20-

-------
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-

-------
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

                               -22-

-------
 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.


                               -23-

-------
      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

                               -24-

-------
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-

-------
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.

-------
                                             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.

-------
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.

-------
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.
                               -26-

-------
 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-

-------
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-

-------
 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-

-------
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-

-------
                                       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-

-------
                                       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.
                               -34-

-------
     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

                               -35-

-------
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,

                               -36-

-------
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

                               -37-

-------
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.
                              -38-

-------