Superfund Record of Decision Langley AFB/NASA Langley Center Tabbs Creek OU Hampton VA


                                    EPA/ROD/R03-98/065
                                    1998
EPA Superfund
     Record of Decision:
     LANGLEY AIR FORCE BASE/NASA LANGLEY
     RESEARCH CENTER
     EPA ID:  VA2800005033
     OU03
     HAMPTON, VA
     09/30/1998

-------
EPA 541-R98-065

RECORD OF DECISION

NASA LANGLEY RESEARCH CENTER

TABBS CREEK OU
September 1998
RECORD OF DECISION
NASA LANGLEY RESEARCH CENTER

DECLARATION

SITE NAME AND LOCATION

NASA Langley Research Center (NASA LaRC)
Tabbs Creek Operable Unit
Hampton, Virginia

STATEMENT OF BASIS AND PURPOSE

This Record of Decision (ROD) presents the selected remedial action for the Tabbs Creek Operable
Unit (OU) at the NASA Langley Research Center (LaRC) in Hampton, Virginia (the "Site"), chosen
in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) of 1980, as amended, 42 U.S.C. °9601 et seg. and, to the extent practicable, the
National Oil and Hazardous Substances Pollution Contingency Plan (NCP), 40 C.F.R. Part 300. This
decision is based on the Administrative Record for this Site.

The Virginia Department of Environmental Quality (VDEQ) concurs with the selected remedy.

ASSESSMENT OF THE SITE

Actual or threatened releases of hazardous substances from this OU, if not addressed by
implementing the response actions selected in this ROD, may present an imminent and substantial
endangerment to public health, welfare or the environment.

DESCRIPTION OF SELECTED REMEDY

The Tabbs Creek OU cleanup is part of a comprehensive environmental investigation and cleanup
currently being performed at the NASA LaRC under the CERCLA program. NASA LaRC is currently
addressing five OUs under its environmental remediation program. The remaining four OUs will be
addressed in other RODs.

This action addresses the principle threat at the OU by dredging and disposing contaminated
sediment.

The selected remedy is dredging and off-site disposal of contaminated sediments and includes:

Dredging of the contaminated sediment from the creek and adjacent marsh areas;
Dewatering of the sediment;
Treating and discharging dredging water;

-------
        Transporting and disposing of the sediment off-site in a Toxic Substances Control Act
        (TSCA)-approved chemical waste landfill;
        Backfilling the dredged sediment/marsh areas;
        Restoring the wetland vegetation;
        Annual biota monitoring;
        Restrictions on biota harvesting for five years;
DECLARATION OF STATUTORY DETERMINATION

The selected remedy is protective of human health and the environment, complies with federal and
State reguirements that are legally applicable or relevant and appropriate to the remedial
action,  and is cost effective. The remedy utilizes permanent solutions and alternative treatment
technologies, to the maximum extent practicable. However, because treatment of the principle
threats of the site was not found to be practicable, this remedy does not satisfy the statutory
preference for treatment as a principal element. The technologies chosen are proven reliable and
cost effective.

Because this remedy will not leave hazardous substances on-site above health-based levels, a
long-term monitoring and five year review of the remedial action will not be necessary. However,
annual biota monitoring for five years will be conducted to determine the effectiveness of the
selected remedy. Should this sampling show that the selected remedy is not protective of human
health and the environment, additional action will be undertaken in full consideration with the
public.

-------
                        TABLE  OF  CONTENTS






SECTION                                                          PAGE






I.      SITE NAME, LOCATION AND DESCRIPTION                     1






II.     SITE HISTORY                                             1






III.    HIGHLIGHTS OF COMMUNITY INVOLVEMENT                     3






IV.     SCOPE AND ROLE OF TTHS REMEDIAL  ACTION                  4






V.      SUMMARY OF SITE CHARACTERISTICS/EXTENT OF CONTAMINATION 4






VI.     SUMMARY OF SITE RISKS                                    6






VII.    DESCRIPTION OF ALTERNATIVES                              9






VIII.   SUMMARY OF COMPARATIVE ANALYSES  OF ALTERNATIVES         10






IX.     SELECTED REMEDY                                          12






X.      STATUTORY DETERMINATIONS                                 13






XI.     DOCUMENTATION OF SIGNIFICANT  CHANGES                     14






XII.    RESPONSIVENESS SUMMARY                                  14






XIII.   REFERENCES                                               16






APPENDIX A - FIGURES






APPENDIX B - TABLES






APPENDIX C - GLOSSARY

-------
                          LIST OF  FIGURES
FIGURE

1A

IB

1C


2A

2B

3A


3B


3C


3D
DESCRIPTION                             PAGE

VICINITY MAP                            A-l

BASE MAP, TABBS CREEK                   A-2

NASA LaRC WEST AREA CONTAMINATED  SITE
LOCATIONS

SEDIMENT SAMPLING RESULTS:  PCB/PCT      A-4

SEDIMENT SAMPLING RESULTS:  PCB/PCT      A-5

BIOTA SAMPLING RESULTS                  A-6
SHRIMP/MUSSEL/OYSTER/CRAB  - ORGANICS

BIOTA SAMPLING RESULTS                  A-7
SHRIMP/MUSSEL/OYSTER/CRAB  - INORGANICS

BIOTA SAMPLING RESULTS                  A-9
WHOLE FISH/FISH FILLET/TURTLE  - ORGANICS

BIOTA SAMPLING RESULTS                  A-9
WHOLE FISH/FISH FELLET/TURTLE  - INORGANICS
        A-3
                CONTAMINATED AREAS  TO  BE  DREDGED
                                                        A-10
TABLE

1


2

3

4

5


6

7
             LIST OF TABLES

DESCRIPTION

SUMMARY OF OPERABLE UNITS UNDER
CERCLA, INVESTIGATIONS

RESULTS OF RME RISK ESTIMATES

VOLUME OF CONTAMINATED  SOIL

EVALUATION OF PROCESS OPTIONS

SUMMARY OF CONTAMINATED SEDIMENT
REMEDIAL ALTERNATIVES EVALUATION

CHEMICAL-SPECIFIC ARARS

LOCATION-SPECIFIC ARARS

ACTION-SPECIFIG ARARS
PAGE

2


B-l

B-2

B-3

B-5


B-7

B-8

B-ll

-------
RECORD OF DECISION

NASA LANGLEY RESEARCH CENTER
TABBS CREEK OPERABLE UNIT

DECISION SUMMARY

I. SITE NAME, LOCATION, AND DESCRIPTION

NASA LaRC is a 787-acre NASA research center located in southeastern Virginia in the Hampton
Roads area. NASA LaRC is bounded by State Route 172 on the West, by Brick Kiln Creek to the
North and by Langley Air Force Base to the South and East (Figure 1, Appendix A). NASA LaRC
together with Langley Air Force Base was proposed for listing on the National Priorities List
(NPL) in 1993; NPL listing was finalized in 1994.

Tabbs Creek is a meandering creek flowing east-northeast into the northwest branch of the Back
River and has marsh 400-2,000 yards wide; thick brush and trees along its perimeter. Four storm
sewers discharge to the upstream portion of the creek from NASA's West Facility. The Tabbs,
Creek drainage area includes part of NASA and Langley Air Force Base, and approximately 20
tributaries drain into the creek. The creek has a 2-3 foot tidal variation under normal
conditions and the surface of the creek is approximately 5 feet above mean sea level. The
water guality in the creek varies, but is generally brackish.

Sediments in the creek consist of fine-grained silts and clays mixed with organic mater. Complex
erosion and deposition patterns exist due to the combination of stream flow, ebbing and rising
tides, surface runoff and discharges, and groundwater movement.

The majority of the marsh is relatively undisturbed and provides exceptional habitat for a
variety of wildlife. This includes forage and/or roosting habits for numerous species of
waterfowl. The banks of Tabbs Creek are not fenced; however, because of its location and extent
of accumulated marshland, access by land is difficult. The lower half of the creek is accessible
by boat. Access to the upper half of the creek is obstructed due to a water pipe crossing the
creek. Figure IB (Appendix A) depicts the major features of the creek and its surrounding areas.

The site is located within the Atlantic Coastal Plain physiographic province. The geology of the
area, primarily flat lying marine sediments, consists of the Norfolk Formation and the Yorktown
Formation. The uppermost soil unit at the site consists of varying seguences of silt, clay, and
silty to clayey sands belonging to the Norfolk Formation. In the boring drilled for the Site
Inspection, this unit occurs from 0 to 9 feet in depth and consists of brown, mottled orange and
gray soils. They are typically dry to moist and slightly to moderately plastic. The underlying
Yorktown Formation consists of gray silty clay and clayey silt with abundant shells and shell
fragments. It is typically wet to saturated, moderately to highly plastic and occasionally
mottled. Local sand tenses are common, as are partially hardened shelly layers (coguina). The
Yorktown Formation extends to approximately 400 feet below grade at the site.

II. SITE HISTORY

This section describes the history of waste disposal, and CERCLA, investigations response
actions at the Site.

A. HISTORY OF WASTE DISPOSAL

The primary function of NASA LaRC is research and development of advanced technologies for
aircraft and spacecraft. Specific studies center on instrumentation, materials fatigue,

-------
acoustics, aerodynamics, and guidance control. In conducting its research and development
mission, NASA LaRC reguires many support facilities including Underground Storage Tanks  (USTs)
for fuel and other raw products, power plants, wind tunnels, laboratories and administrative
buildings. All of these facilities have the potential to impact the environment through disposal
activities, material(s) transportation and inadvertent releases such as spills or mechanical
malfunctions.

There are currently 5 Operable Units being investigated under CERCLA at NASA LaRC. They include:
the Construction Debris Landfill, the Chemical Waste Pit, Area E Warehouse, Stratton Substation
and Tabbs Creek. A brief summary of these areas is provided on Table 1. Figure 1C  (Appendix A)
provides the location of these areas. The 4 other Operable Units will be addressed in separate
Records of Decision.

-------
               Table 1. Summary of Operable Units Under CERCLA Investigations
OU Name

Construction Debris Landfill




Chemical Waste Pit
Area E warehouse
Stratton Substation
Findings

Organic and inorganic
contaminants found in
groundwater, surface water,
sediment,  and soil.

Chemical wastes reportedly buried
at the site.
Low levels of Polychlorinated
Biphenyls (PCBs)  and metals
contaminated soils.
PCB contaminated soil.
Current Status

Draft Remedial
Investigation/Feasibility Study
(RI/FS) under regulatory review
Chemical Waste Pit was found to
be located within the boundaries of
the Construction Debris Landfill
(CDL)  OU and is addressed in the
CDL RI/FS.

Record of Decision to be signed by
the end of FY98.  Remedy is the
implementation of institutional
controls  (land use restrictions).

Draft Final Focused RI/FS
currently under regulatory review.
PCBs and Polychlorinated Terphenyls  (PCTs) were inadvertently discharged into several NASA LaRC storm sewers
and eventually deposited in Tabbs Creek. The contamination in the storm sewers and contamination source have
been cleaned up pursuant to Federal Facilities Compliance Agreement (FFCA)  Docket No. III-FF-CWA-003.

-------
B. CERCLA INVESTIGATIONS

NASA completed CERCLA, Preliminary Assessment (PA) and Site Inspection (SI) Reports in 1988 and
1989, respectively. In 1993, NASA LaRC, together with Langley Air Force Base (LAFB), was
proposed for inclusion on the National Priorities List (NPL) and included on the NPL in 1994. A
Federal Facilities Agreement (FFA) was signed by EPA, NASA and the Virginia Department of
Environmental Quality (VDEQ) in 1994. The FFA establishes a procedural framework and schedule
for implementing site cleanups at NASA LaRC (the Site).

In 1982, Water and Air Research, under contract to the U.S. Air Force Occupational and
Environmental Health Lab, collected groundwater, surface water, and sediment samples to study
the effects of several local landfills adjacent to Tabbs Creek (U.S. Air Force, 1982). Results
indicated that the landfills had discharged pollutants to the creek. However, at that time no
significant contamination of the creek existed and periodic water sampling was recommended.

Oyster samples were collected and analyzed for PCBs and PCTs in 1988 as part of a study
conducted by Robert C. Hale, College of William and Mary/Virginia Institute of Marine Sciences
(VIMS) (Hale, 1990a). Samples collected at the bridge crossing Tabbs Creek contained elevated
levels of PCBs and PCTs relative to other samples obtained from the Back River vicinity. By
studying the distribution of PCT in sediment and its bioavailability to aguatic organisms, Hale
indicated that the sediment contained elevated levels of PCTs throughout the creek (Hale,
1990b).

In 1989, Bionetics Analytical Laboratory, under contract with NASA, reported that sediment
samples were contaminated with PCBs and PCTs in Tabbs Creek (NASA, 1990). The results indicated
a general decrease in concentrations progressing downstream; however, levels were still elevated
compared to the background sample at the Back River.

In 1991, the Preliminary Site Characterization was completed by Foster Wheeler Environmental,
formerly Ebasco, as the initial phase of Remedial Investigation (RI) (Ebasco, 1991).
Contaminants of concern (COCs) identified included pesticides, PCBs, PCTs, volatiles,
semivolatiles, and several Target Analyte List (TAL) metals. PCB and PCT levels appeared to be
below levels found in previous investigations.

An engineering assessment of the Storm Sewers at NASA LaRC was completed by Foster Wheeler
Environmental in 1992 (Ebasco, 1993). Data indicated that manholes and catch basins were
contaminated with PCBs and PCTs. The portion of storm sewer that drains through Outfall 009 into
Tabbs Creek was determined to be the source of PCB/PCT contamination of Tabbs Creek. The West
Area storm sewer has since been cleaned up to eliminate the source of contamination.

Kathryn Gallagher of the College of William and Mary/VIMS conducted an investigation to
determine the levels of PCTs in aguatic organisms in Tabbs Creek (Gallagher, 1992). Results
indicated the species contained PCTs and their concentrations generally decreased with distance
downstream.

A Remedial Investigation (RI) was performed by Foster Wheeler Environmental in 1991 and 1992
(Foster Wheeler Environmental, 1998). The investigation consisted of sampling and analysis of
surface water, sediment, and biota samples for both organic and inorganic contamination. The
results were used to conduct human health and ecological risk assessments. The results indicated
that concentrations up to 760 parts per million (ppm) of PCBs and PCTs were found in sediment
samples from the creek, with PCTs dominating in concentrations and sampling locations. The
contamination was primarily confined to the area of the creek bed and the highest levels were
found in the upper estuary near Stotm Sewer Outfall 009.

-------
Based on the results of the remedial investigation and risk assessments, a Feasibility Study
(FS) was conducted by Foster Wheeler Environmental for Tabbs Creek site from 1992 to 1996
(Foster Wheeler Environmental, 1998).

III.    HIGHLIGHTS OF COMMUNITY PARTICIPATION

In accordance with Sections 113 and 117 of CERCLA, 42 U.S.C. Sections 9613 and 9617, NASA, in
conjunction with EPA, issued a Proposed. Plan on August 31, 1998, presenting the preferred
remedial alternative for the Tabbs Creek OU. The Proposed Plan and the supporting documentation
became available for review at that time and are among the documents which comprise the CERCLA
Administrative Record for NASA LaRC.

The Administrative Record is and has been available for review by the public at the following
information repositories:

                 Poguoson Public Library            Floyd L. Thompson Library
                 800 City Hall Avenue               NASA LaRC
                 Poguoson, Virginia                 Hampton, Virginia
An announcement for an availability session, the comment period, and the availability of the
Administrative Record for the remedy for the Tabbs Creek OU was published in the Daily Press on
August 28 and 30, 1998, the Poguoson Post on September 2 and 9, 1998, and the Yorktown Crier on
September 2 and 9, 1998. The public comment period for the Proposed Plan was from August 28,
1998 to September 26, 1998. A public availability session was held at the Virginia Air and Space
museum in Hampton, Virginia on September 14, 1998, to inform the public of all the remedial
alternatives and to seek public comments. At this meeting, representatives from NASA, USEPA,
VDEQ, Foster Wheeler (an environmental consultant) were available to answer guestions about
conditions at the site and the remedial alternatives under consideration. Responses to the
comments received during this period are included in the Responsiveness Summary section of this
ROD.

All documents considered or relied upon in reaching the remedy selection decision contained in
this ROD are included in the Administrative Record for the Site and can be reviewed at the
information repositories.

IV.     SCOPE AND ROLE OF THIS REMEDIAL ACTION

Discrete portions of an NPL site are often managed more effectively as Operable Units (OU). NASA
has organized work to date into five operable units. This ROD for the Tabbs Creek OU addresses
PCB and PCT contaminated sediment. The other Operable Units are:

               Construction Debris Landfill
               Chemical Waste Pit
               Area E Warehouse
               Stratton Substation

These four other Operable Units are undergoing independent CERCLA investigations and will be
addressed in separate Records of Decision.

V.       SUMMARY OF SITE CHARACTERISTICS AND EXTENT OF CONTAMINATION

Summarized below am the relevant findings of the work to date with regard to contaminated soil
located within the boundaries of the NASA LaRC including the Tabbs Creek OU.

-------
A. SITE CHARACTERISTICS

1. Ecology

Open land, woodland, wetland and aquatic habitats are all found within or near NASA LaRC. These
include mowed fields and lawns, nonfcrested overgrown land, wooded areas, forested wetlands,
scrub/shrub wetlands, creeks, tributaries and streams.

2. Soils

Soil at the Tabbs Creek OU has generally been graded and/or filled to support buildings and road
surfaces. Coarse sand and gravel is found within the upper two feet of the ground surface. Grass
covered areas were graded with topsoil and some subsurface soil samples encountered the Norfolk
Formation.

3. Groundwater Use

Groundwater in the area can be found at a depth of 5 to 50 feet below the land surface. This
aguifer, known as the Columbia aguifer, is brackish and its use is limited to lawn and garden
watering. It is currently not used or usable as a source of potable water. Both the Yorktown and
the Yorktown-Eastover aguifers underlie the Columbia aguifer. The Yorktown-Eastover aguifer is
confined and is used at other locations as a source of domestic potable water, Groundwater is
not being addressed as part of this remedial action.

B. NATURE AND EXTENT OF CONTAMINATION

The following is a summary of the sampling results of the Remedial Investigation.

Surface Water

PCBs and PCTs were not detected in the surface water samples. Only low levels of several organic
contaminants were detected in a few surface water samples. These include methylene chloride (7
ppb), acetone (1100 ppb), chloroform (9.3 ppb), trichloroethane (71 ppb), 1,1-dichloroethane (10
ppb), 1,1-dichloroethene (4.7 ppb), bromodichloromethanbe (3 ppb).

Inorganic contaminants were found in all surface water samples. The maximum concentrations of
arsenic (194 ppb), copper (643 ppb), lead (16.1 ppb), silver (8-6 ppb), zinc (316 ppb), and
cyanide (10.9 ppb) in the unfiltered samples exceeded either EPA's Ambient Water Quality
Criteria (AWQC) or Virginia standards for surface waters. Results of filtered samples indicated
that only arsenic (162 ppb) exceeded the Virginia standards in more than one sample. Copper
(20.5 ppb) and nickel (9.7 ppb) had one exceedance at Outfall 009. Note that arsenic
concentrations were randomly distributed throughout the creek and the background stations,
indicating that LaRC may not be a source of arsenic in surface water.

Sediment

Up to 760 ppm of PCBs and PCTs were detected with the highest concentrations in the upper
estuary near the Storm Sewer Outfall 009. PCT concentration levels were generally greater than
PCB levels and found more freguently at sampling locations. Figures 2A and 2B (Appendix A) show
the investigation results.

Pesticides, including DDD, DDE, DDT, dieldrin, endosulfan II, endosulfur sulfate and
methoxychlor, were detected at low concentrations in 8 of 70 samples. Maximum levels of these
include DDD at 96 ppb, DDE at 160 ppb, DDT at 60 ppb, dieldrin at 45 ppb, endosulfan II at 13

-------
ppb, endosulfan sulfate at 900 ppb and methoxychlor at 32 ppb. No spatial pattern was evident,
indicating that the contamination was not related to any direct or point source discharge.

Polynuclear aromatic hydrocarbons (PAHs) were detected in seven of 68 sediment samples with
concentrations of total PAHs greater than 10 ppm. Four samples showed total PAHs between 5 and
10 ppm. Contaminant levels were higher in the upper estuary and at the Storm Sewer outfalls.

The arsenic concentrations at the outfalls and in the creek were generally higher than the
background samples. However, all levels were within the natural background ranges of U.S. clays
and soils (Dragun, 1988). Chromium copper, lead, mercury, silver, and zinc occurred in
concentrations exceeding the natural background ranges of U.S. clays and soils, usually in the
upper portion of the estuary. Source(s) of these metals can not be positively identified. It is
suspected that the landfills along Tabbs Creek may have contributed to the metal contamination.

Several dioxin or furan isomers were detected at Outfall 008 at concentrations higher than the
background levels. The concentrations of octachlorodibenzodioxin (OCDD) (115 ppb) and total
heptachlorodibenzo p-dioxin (HpCDD) (28 ppb) were significantly greater than that of the maximum
local background levels of 1.6 ppb (estimated) and 0.3 ppb, respectively. The sample from
Outfall 008 also contained tetrachlorodibenzodioxin (2,3,7,8-TCDD) at an extremely low
concentration (0.02 ppb). PCBs and PCTs were not detected in samples taken from Outfall 008.

Sediment Toxicity Characteristic Leaching Procedure (TCLP) results revealed no leachate samples
with contaminant concentrations albove the maximum toxicity characteristic levels.

Biota

Biota samples, including saltmarsh cordgrass, shrimp, mussel, blue crabs, fish, fish fillet, and
snapping turtle, were collected and analyzed. PCBs and/or PCTs were detected in saltmarsh
cordgrass, mussel, blue crabs, fish, and fish fillet, with concentrations decreasing from
Outfall 009 toward the background station. Pesticides, including chlordane, dieldrin, 4,4'-DDD,
and 4,4'-DDE, and metals were detected in some of the biota samples; however, there were no
obvious pattern distributions observed. Figures 3A, 3B, 3C, and 3D (Appendix A) depict the
sampling results.

VI. SUMMARY OF SITE RISKS

A risk assessment was conducted as part of the RI in accordance with the latest EPA policy on
Risk Assessments (USEPA, 1989). The results are summarized below.

Human Health Risk Assessment

Health risks are based on a conservative estimate of the potential carcinogenic risk or
potential to cause other health effects not related to cancer. Carcinogenic risks and
noncarcinogenic risks were evaluated as part of the risk assessment; three factors were
considered:

1. nature and extent of contaminants at the OU,
2. the pathways through which human health and ecological receptors are or may be exposed to
those contaminants at the OU, and
3. potential toxic effects of those contaminants.

Cancer risks are expressed as a number reflecting the increased chance that a person will
develop cancer, if he/she is directly exposed to the contaminants found in the groundwater,
surface water, soil and sediment at the OU for 30 years. For example, EPA's acceptable risk

-------
range for cancer is 1 x 10 -4 to 1 x 10 -6, meaning there is one additional chance in ten
thousand (1 x 10 -4) to one additional chance in one million (1 x 10 -6) that a person will
develop cancer if exposed to a hazardous waste site. The risk associated with developing other
health effects is expressed as a hazard index. A hazard index of one or less means that a person
exposed to a hazardous waste site is unlikely to experience adverse health effects. A hazard
index is also used to evaluate ecological risks.

The Risk Assessment in the Tabbs Creek Site RI Report (Foster Wheeler, 1998) identified a number
of potential exposure pathways for facility workers and local residents as follows:

1. Dermal contact with and inadvertent ingestion of sediment in Tabbs Creek and the marsh;

2. Dermal contact with surface water;

3. Inhalation of particulates and contaminants volatilized from sediment and surface water,
and

4. Consumption of oysters, crabs, and fish from Tabbs Creek and the adjacent marsh areas.

The receptors considered as part of the Reasonable Maximum Exposure (RME) Risk Assessment are as
follows: future youth trespassers; sewer maintenance workers; crab and oyster harvesters;
hunters; adult crab, fish, and oyster consumers and youth crab, fish, and oyster consumers.
Exposure parameters used for the Tabbs Creek RME Risk Assessment were largely based on EPA
Region III guidance, EPA Standard Default Exposure Factors Guidance, EPA's Risk Assessment
Guidance for Superfund, which is often referred to as RAGS, and EPA's Dermal Exposure Assessment
manual.
Table 2 (Appendix B) summarizes the results of RME risk calculations for various exposure
scenario cases. Based on the results of the risk calculations, cancer risks from exposure to
contaminated sediment and consumption of contaminated biota exceeded EPA's target range. The
contaminants of concern (COCs) which were responsible for most of the risk include PCTs (for all
pathways), PCBs (fish consumption) and dieldrin (crab consumption). For noncarcinogenic risk,
only oyster and crab consumption pathways slightly exceeded the hazard index of 1. The principal
agents driving the noncancer risks for oyster consumers was zinc; for crab consumers were
dieldrin, silver, copper and bis(2-ethylhexyl)phthalate.

For all the pathways, biota ingestion dominated the total multipathway risks and hazard indices
for all of the populations. The COCs which were responsible for most of the risk are the PCT
Aroclor 5432 and the PCB Aroclor 1248.

The lifetime cancer risks and hazard indices for the non-carcinogenic effects associated with
human contact with contaminated sediment and biota, is presented in Table 2 (Appendix B).

Ecological Risk Assessment

A risk characterization was conducted to address the following Ecological Risk Assessment
endpoints of concern for the Tabbs Creek system: (1) reductions in species diversity and/or
abundance; (2) acute (lethal) and/or chronic (sub-lethal) toxicities of site-related
contaminants to biota; and (3) bioaccurnuiation of site-related contaminants and conseguent
trophic transfers which may occur. PCBs and PCTs were selected ecological COCs for the
ecological risk assessment because of their concentrations in the sediment.

-------
Based on the results of the benthic invertebrate surveys, there do not appear to be any
statistically significant differences in species diversity  (richness) or abundance between the
sample and background stations. In addition, laboratory sediment bioassays conducted on Tabbs
Creek sediments using Ampelisca abdita  (a common estuarine amphipod) and Nereis virens  (a
polychaete worm) demonstrated no statistically significant differences in survival between the
sample and background stations. This indicates that concentrations of PCTs (and other ecological
COCs) in Tabbs Creek sediments are not acutely toxic  (lethal) to the benthic community.

Although a limited number of metals, PAHs, and pesticides were detected in sediment and biota
samples, and may be causing chronic stresses to aguatic/wetlands organisms, the most significant
ecological COCs are PCBs  (Aroclor 1260)  and PCTs (Aroclor 5432) because their concentrations in
sediment are well over an order-of-magnitude higher than those for other COCs. Therefore the
Ecological Risk Assessment focused primarily on potential impacts of PCBs and PCTs mid sediment
cleanup goals were derived based on these compounds. The results of the bioaccumulation analyses
and probabilistic food chain model indicated that direct uptake of PCBs, and potentially PCTs,
from sediments and subseguent trophic transfers are occurring in Tabbs Creek.

C.       CONCLUSIONS

The remedial action objectives are to protect human health and the environment. Based on
available information, and standards such as applicable or relevant and appropriate reguirements
of federal and state law  (ARARs),  and risk-based levels established in the risk assessments, the
remedial action objectives for the Tabbs Creek Site are presented for surface water and
sediment. As indicated in the human health and ecological risk assessments, PCBs and PCTs in
sediment are the primary site contaminants that posed the most risk to human health and the
environment.

Surface Water

PCBs and PCTs were not detected in surface water. Although several metals, arsenic, copper, and
nickel were detected at concentrations exceeding the AWQC or Virginia Water Quality Standards in
surface water samples, including samples from the background locations, both the Human Health
and Ecological Risk Assessments concluded that the contaminants in surface water did not pose
significant risks to human health and the environment. Therefore, no remedial action for surface
water is reguired.

Sediment

The Human Health Risk Assessment concluded that direct exposure to contaminated sediment would
pose a cancer risk slightly exceeding the EPA's acceptable risk range of 10 -6 to 10 -4.
However, the consumption of PCB- and PCT-contaminated biota would pose risks higher than 10 -4
and, in the case of crab ingestion, higher than 10 -3. The ecological assessment indicated that
PCTs may have caused chronic stress to aguatic organisms. In view of the results from the human
health and ecological assessment,  the remedial action objective for the sediment would be to
remediate PCBs and PCTs in sediment to a level that is protective of human health and the
environment. A cleanup level of 5 ppm of total concentration of PCBs and PCTs is recommended for
the Tabbs Creek site based on the protection of the ecological receptors, including human
beings. The reasons for selecting the 5 ppm cleanup level include:

(1)  Based on the food chain model, the 5 ppm cleanup level provides the most conservative
approach to protect human health and the environment;

(2)  The 5 ppm cleanup level would remove almost all hot spots of contamination yet disturb only
a relatively small area (1.4 acres) of the total creek which is comprised of approximately 60

-------
acres; and

(3) When compared to a less conservative cleanup level (e.g., 10 ppm) , the dredging area is
increased only to 1.4 acre from 0.7 acre for the cleanup level of 10 ppm. This dredging area is
small as compared to approximately 60 acres of creek.

The recommended cleanup level is based on the assumption that PCBs and PCTs would have similar
toxic effects because of their similarity in molecular structure. This approach is considered
conservative because there is no toxicity data for PCTs and PCTs are currently not regulated.
Once the cleanup level in sediment is achieved, chronic stress to biota would be reduced.
Because the other potential contaminants including DDT. PAHs and organics were generally found
within the recommended cleanup area, it is assumed that when the PCB and PCT contaminated
sediment is removed, these other contaminants will also be removed.

Contaminated Sediment Areas and Volumes

Using the 5 ppm cleanup level established, the total contaminated sediment area was estimated to
be 1.4 acres. The total contaminated sediment volume was estimated at approximately 4,300 cubic
yards. Figure 4 (Appendix A) depicts the areas with total PCB and PCT concentrations exceeding
the cleanup level. Table 2 (Appendix B) summarizes the calculations and the assumptions used for
the calculations. Note that the assumptions used are believed to be conservative and the final
cleanup volume and area may be different from the estimate. Areas and volume of sediment to be
dredged will be further refined during the design and remediation phase of the project.

Most of the contamination is located near Outfall 009 (see Figures 2A and 2B, Appendix A) and
its downgradient area. In the areas of Outfall 009, point bars (sampling areas) 5, 6, 7, 9, 10,
11, 12, and 13, and sample points T5MC, T6MC, and P14MCP13, PCB and PCT contamination is from
the surface to deeper levels (approximately 4 feet), and exceeds the cleanup level. These areas
contain the majority of the contamination (hot spots) and pose the greatest risk to biota
because the contamination is at the surface.

At sample locations P14MC, P16MCP15, SSP18-10, P19L3, and P22L4/SSP22-5 contamination is
isolated and slightly exceeds the cleanup level. Remediation of these five areas, i.e., dredge
the top 6" to 4' of sediment, would be considered during the remedial design/action phase based
on field conditions, such as, ease of access and potential harm to the environment from the
construction activities.

VII. DESCRIPTION OF ALTERNATIVES

The sediment remediation technologies were identified and screened using effectiveness and
implementability as the criteria. The screening process is described in Table 3 (Appendix B).
Table 4 (Appendix 3) summarizes the process options that were retained to form alternatives,
with two process options (dewatering and process water treatment) retained as support
technologies. Using these retained process options, three alternatives: 1) no-action,
2) dredging/off-site incineration; and 3) dredging/off-site disposal in a TSCA landfill were
developed for detailed analysis as follows:

Alternative 1 - No Action

The NCP reguires that a no action alternative be considered to provide a baseline for comparison
with action alternatives. Under this alternative, no remedial action would be undertaken at this
time to address contaminated sediment at the Tabbs Creek OU.

A long-term (30 years) monitoring program would be conducted. The program would include annual

-------
monitoring of biota, sediment, and surface water, and reviews of the sample results every 5
years. A recommendation for further courses of action would be provided at five-year reviews.

Capital Cost: $10,000
Operations and maintenance (0 & M) cost: $31,000
Net Present Worth: $420,000

Alternative 2: Dredging/Off-Site Incineration

Alternative 2 is a source removal alternative in which approximately 4,300 cy of the
contaminated sediment from the creek and the adjacent marsh areas would be dredged (Note:
Dredging is selected as representative process option for alternative development. Other
methods, including excavation, will be evaluated during remedial design), dewatered, and shipped
off-site for treatment by an incinerator. Dredging water will be treated and tested to ensure
that water guality standards are being met. If EPA and the Army Corps of Engineers determined it
is beneficial to the environment, the dredged sediment areas would be restored to the original
grades with clean fill and replacement of vegetation. Figure 4, Appendix A, shows the
approximate areas of contaminated sediment to be dredged.

To achieve the remedial action objective, the top 6" to 4' of sediment, where most biological
exposures occur, from the above identified areas would be dredged. Dredging would start from
Outfall 009 continuously to P14MCP13, and then to the individual hot spots. Once the dredged
areas are backfilled with uncontaminated sediment, biota would only be exposed, to clean
sediment. For the remaining areas of the creek, only minor contamination, with most samples in
the non-detect to 5 ppm range, was detected. The average residual contamination is estimated at
approximately 2.1 ppm, which is significantly below the cleanup level of 5 ppm. All ARARs would
be met (see Tables 6, 7 and 8, Appendix B).

Long-term monitoring would not be required since the contaminated sediment, with concentrations
of PCBs/PCTs greater than 5 ppm, would have been removed from the site. However, annual biota
monitoring, consisting of live box studies, would be conducted for 5 years to determine the
effectiveness of this remedy.

Fishing, crabbing, and shellfish harvesting would be banned in Tabbs Creek during these 5 years.
Signs would be posted along the perimeter of the creek to serve the purposes.

Capital Cost: $12,800,000
Operations and maintenance: (0 & M) cost: $25,000
Net Present Worth: $13,000,000

It is anticipated that the time required to achieve remedial action objectives for this
alternative is approximately 12 months: 4 months for the preparation and approval of the design;
4 months for site preparation, 3 months for dredging and dewatering operations and one month for
demobilization.

Alternative 3: Dredging/Off-Site Disposal

Similar to Alternative 2, this is also a source-removal alternative, except that the
contaminated sediment would be disposed of off-site at a TSCA permitted chemical waste landfill
instead of treated at an incineration facility. The dredging, dewatering, dredge-water
treatment, backfilling and restoration, and monitoring would be the same as discussed in
Alternative 2. All ARARs would be met (see Tables 6, 7 and 8, Appendix B).

Capital Cost: $4,700,000

-------
Operations and maintenance (0 & M) cost: $25,000
Net Present Worth: $4,800,000

As with Alternative 2, it is anticipated that the time required to achieve remedial action
objectives is approximately 12 months.

VIII. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES

During the detailed evaluation of remedial alternatives, each alternative is assessed against
the following nine evaluation criteria: overall protection of human health and the environment;
compliance with applicable or relevant and appropriate requirements (ARARs); long-term
effectiveness and permanence, reduction of toxicity, mobility, or volume; short-term
effectiveness; implementability; cost; regulatory acceptance; and community acceptance.

A comparative analysis for the three alternatives based on these evaluation criteria is
presented in the following sections. In addition, Table 5 (Appendix B) provides a summary of
contaminated sediment remedial alternatives evaluation.

A. OVERALL PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT

Alternative 1 provides no remedial action and the creek would continue to be contaminated. The
existing ban on shellfish fishing would provide some limited protection to human health but not
the environment. Alternatives 2 and 3 would provide protection to human health and the
environment from exposure to the contaminated sediment since the surface sediment with
contamination above the cleanup levels for PCBs and PCTs would be removed from the site.
Contaminated biota will die off gradually and disperse into the sediment. Over time, the new
generations of biota will have less and less contamination from the site. With off-site disposal
of contaminated sediment, Alternative 3 would contain contaminants in a controlled environment
(i.e., a landfill meeting TSCA-PCB disposal requirements). With off-site incineration,
Alternative 2 would destroy the contaminants. Alternative 2 would be most effective because the
destruction process is not reversible. However, Alternative 3 also meets this criteria because
it provides protection of human health and the environment and is more cost effective than
Alternative 2.

Remedial activities in Alternatives 2 and 3 would cause short-term impacts to the wetland. These
activities are essentially unavoidable to provide access to the wetland to remove the
contaminated sediment and allow for final grading and restoration of the wetland. In all cases,
it is the intent of the alternatives to restore the wetland to its original beneficial use,
although time would be required for biota to become reestablished in the disturbed areas.
Alternative 1 with no remedial activities would not incur disturbance of the wetland.

B. COMPLIANCE WITH ARARS

TSCA requirements for disposal of PCB contaminated sediments is applicable and therefore an
action-specific ARARs for contaminated sediment. The cleanup level was derived to protect biota
and consumers of biota at the site. Alternatives 2 and 3 would meet the cleanup level by
removing the sediment with contamination exceeding the level and treating/disposing the sediment
at an offsite facility. These alternatives would meet the remedial action objectives. For
Alternative 1, the cleanup level would not be attained.

Alternatives 2 and 3 would likely attain the AWQC for surface water once the source has been
removed. Alternative 1 might not comply with the AWQC as the source would not be remediated.
Alternatives 2 and 3 would comply with State Pollutant Discharge Elimination System
(SPDES)-discharge requirements for surface water pumped and created from the marsh. Alternative

-------
1 would not involve discharging any water.

Remedial activities at the marsh would comply with location-specific ARARs. Alternatives 2 and 3
would involve work in the wetland and floodplain. The activities would be of short duration and
the wetland would be restored under these alternatives. Engineering measures would be
implemented to prevent impact from a potential 100-year flood during remediation. Alternative 1
would not incur any disturbance of the wetland or floodplain and would, therefore, these
location-specific ARARs do not apply. Endangered species are not known to be present at the
site.

All alternatives would be executed in a manner that is in compliance with action-specific ARARs
such as OSHA, RCRA facility standards, transportation and manifest documentation, and air
emissions. Tables 6, 7, and 8 (Appendix B) stipulate the chemical-specific, location-specific
and action-specific ARARs, respectively, and their design considerations.

C. LONG-TERM EFFECTIVENESS AND PERMANENCE

Alternatives 2 and 3 would be effective in addressing the site contaminants since the sediment
with contamination above the cleanup level would be completely removed from the site.
Alternative 2 would be most effective in the long term since incineration of contaminated
sediment is not reversible and does not reguire long-term maintenance. Alternative 3 would
provide off-site containment of PCBs and PCTs, which would be less effective than the treatment
processes. A landfill will reguire long-term proper maintenance.

Alternative 1 would not provide any type of remedy for the contaminated sediment; therefore,
future remedial actions would probably be reguired.

D. REDUCTION OF TOXICITY, MOBILITY, OR VOLUME THROUGH TREATMENT

Alternative 2 would reduce the toxicity, mobility, and volume of contaminated sediment at the
Tabbs Creek site through treatment. Alternative 3 does not involve treatment. Alternative 1
would not reduce the toxicity, mobility, or volume of the contaminants. The treatment process
under Alternative 2 is irreversible. Although Alternative 3 does not reduce toxicity mobility or
volume through treatment, it is protective of human health and the environment and more
cost-effective than Alternative 2. In addition, principal threats for which treatment is most
likely to be appropriate include liguids, areas contaminated with high concentrations of toxic
compounds, and highly mobile materials. Conditions at the Tabbs Creek OU do not meet these
criteria to warrant treatment, but do warrant removal of contaminated sediment.

E. SHORT-TERM EFFECTIVENESS

Alternative 1 would not involve any construction activities; therefore, it would provide the
least short-term risks to the community, workers, and the environment.

Alternatives 2 and 3 would reguire dredging, dewatering, and handling of contaminated sediment,
posing some risk of contact to workers and residents. Engineering measures would be implemented
to protect the workers and the community. They may also cause a traffic inconvenience to
neighboring communities.

Once on-site work begins, Alternatives 2 and 3 would reguire approximately 8 months to Complete
and achieve remedial action objectives in 12 months. Alternative 1 does not involve any on-site
work and does not meet remedial action objectives.

F. IMPLEMENTABILITY

-------
Alternative 1 would be the easiest alternative to implement since no construction activities
would be performed at the Tabbs Creek Site. However, if additional remedial action is required
in the future, Alternative 1 would be more difficult to implement as time goes by since the
contamination would spread to a larger area.

Alternatives 2 and 3 would involve removal of the contaminated sediment from the creek area.
There would be some difficulty in maneuvering the dredging equipment and support equipment
because of the shallow and narrow nature of the creek and the low-bearing capacity of the
surrounding area. However, dredging, dewatering, and waste transporting would use common
equipment and procedures. Incineration and landfilling in Alternatives 2 and 3 are also common
and proven technologies utilized in PCB remediation. After removal of contaminated sediment,
clean material would be used to backfill the dredged area. Restoration of wetlands would also be
conducted if required. However, the restoration process is not a proven technology.

G. COST

Alternative 1 has long-term monitoring costs associated with implementation. Alternative 2 would
eliminate long term maintenance costs and reduce toxicity, mobility, and volume at a significant
increase in cost over the other alternatives. Alternative 3 would provide protection similar to
Alternative 2, but at approximately one third the cost of Alternative 2. Alternative 3 is the
more cost-effective alternative. It will meet all remediation goals (in contrast to Alternative
1) with significantly less cost than Alternative 2.

H. STATE ACCEPTANCE

The Virginia Department of Environmental Quality concurs with the selection of Alternative 3,
Dredging and Off-Site Disposal as the selected remedy for this OU.

I. COMMUNITY ACCEPTANCE

An availability session on the Proposed Plan was held on September 14, 1998 in Hampton,
Virginia. Comments received orally and/or in writing at the availability session are referenced
in the Responsiveness Summary (Section
XII of this ROD).

IX. SELECTED REMEDY

Following review and consideration of the information in the Administrative Record file,
requirements of CERCLA, and the NCP, and the public comments reviewed on the Proposed Remedial
Action Plan, NASA and EPA, in consultation with VDEQ, have selected Alternative 3:
Dredging/Off-Site Disposal as the remedy for the Tabbs Creek Operable Unit. This remedy would
prevent unacceptable exposure to contaminated sediment.

Based on available information, NASA and EPA believe that the selected remedy would be
protective of human health and the environment, would be cost effective, and would provide the
best balance of trade-offs among the alternatives with respect to the evaluation criteria.

The selected remedy for the Tabbs Creek OU includes the following major components:

6 Dredging of the contaminated sediment from the creek and adjacent marsh areas;
6 Dewatering of the sediment;
6 Treating and discharging dredging water
6 Transporting and disposing the sediment off-site in a TSCA-approved chemical waste
landfill;

-------
6 Backfilling the dredged sediment/marsh areas
6 Restoring wetlands
6 Annual biota monitoring; and
6 Restrictions on biota harvesting for five years

The present worth of this remedy is $4,800,000.

PERFORMANCE STANDARDS

Dredging/Off-Site disposal shall remove all sediments with concentrations greater than 5 ppm.
This includes dredging to a depth of 4 feet in certain areas. All dredging water shall be
treated and tested to ensure compliance with water guality standards prior to discharge into
Tabbs Creek. To mitigate the loss of productive wetlands and habitats and to reduce the erosion
after dredging, the site shall be restored by replanting vegetation and sediment replacement.

X. STATUTORY DETERMINATION

A. PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT

The selected remedy, Alternative 3, would protect human health and the environment by preventing
exposure through the removal (dredging) of the contaminated sediments and containment in a
landfill designed to store PCBs and PCTs.

B. COMPLIANCE WITH ARARS

The selected remedy will comply with all ARARs including TSCA (see Tables 6, 7, and 8, Appendix
B). The remedial action objectives will be met by the selected alternative since the
contaminated sediment in excess of the cleanup level will be removed. Since the source (the
sediment) will be removed, concentrations of contaminants in the surface water should remain
below AWQC.

With regard to location-specific ARARs, the selected alternative will comply with the wetland
protection Executive Order (E.O.) No. 11990 because wetlands will be reestablished. Flood
control capacity would not be affected since the creek system will be backfilled to the original
grades when necessary. The dredged sediment and wastewater treatment facilities will be located
within the 100-year floodplain. Engineering measures such as berms or locating eguipment above
the flood level can easily be provided. Therefore, this alternative is considered to be in
compliance with Federal Floodplain Management E.O. No. 11988. Since the wetland would be
disturbed, compliance with Section 404 and Section 10 reguirements will be necessary.

The selected alternative will comply with action-specific ARARs which include OSHA, Section 404
permit reguirements, state discharge criteria (SPDES), air emissions standards, and
transportation and disposal regulations (see Table 8, Appendix B).

C. COST EFFECTIVENESS

The selected remedy is cost-effective. The present worth cost is $4,800,000.

D. UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATE TREATMENT TECHNOLOGIES
OR RESOURCE RECOVERY TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE

The removal of contaminated sediment in the selected alternative would permanently reduce the
volume of contaminants in the marsh and creek. After the remedial action is completed, residual
risks around the site would be within an acceptable level. The possibility of contaminated

-------
sediment contaminating surface water to levels exceeding AWQC would also be eliminated. The
wetland would be restored under this alternative. Off-site disposal of contaminated sediment in
a landfill would control the mobility of the contaminants.

The selected remedy does not utilize permanent treatment technologies for this site due to cost
and other considerations. Although this action does not fully address the statutory mandate for
treatment, this action provides for a permanent remedy and thus partially satisfies this
mandate.

E. PREFERENCE FOR TREATMENT AS A PRINCIPLE ELEMENT

The selected alternative does not treat the contaminants. However, dredging and off-site
disposal are proven and reliable technologies, and would achieve the remedial action objectives
as effectively as the treatment alternative at the site.

XI. DOCUMENTATION OF SIGNIFICANT CHANGES

The proposed plan for the Tabbs Creek OU was released for public comment on August 28, 1998. The
Proposed Plan identified Alternative 3, Dredging/Off-Site Disposal, as the preferred
alternative. NASA, EPA and VDEQ reviewed and considered all comments received during the public
meeting and during the public comment period. Upon review of these comments, it was determined
that no significant changes to the remedy, as originally identified in the Proposed Plan, are
necessary.

XII. RESPONSIVENESS SUMMARY

A.  OVERVIEW

In a Proposed Plan released for public comment on August 28, 1998, NASA, with the support of
EPA, identified Alternative 3 as the preferred remedial alternative for the Tabbs Creek OU at
the Site. Alternative 3 in the Proposed Plan was described in Section VIII.

B. COMMUNITY INVOLVEMENT TO DATE

NASA and EPA established a public comment period from August 28, 1998 to September 26, 1998 for
interested parties to comment on the Proposed Plan the Remedial Investigation and the
Feasibility Study and other documents pertaining to the Tibbs Creek OU. These and all other
documents considered or relied upon during the remedial selection process for the Tabbs Creek OU
are included in the Administrative Record, which has been in two information repositories
accessible to the public since the beginning of the public comment period for the Tabbs
Creek OU. An availability session was held at the Virginia Air and Space Center on September 14,
1998 to present the Proposed Plan, answer guestions, and accept both oral and written comments
on the Tabbs Creek OU remedial alternatives. Three people attended this session.

C. SUMMARY OF RESPONSES RECEIVED DURING THE PUBLIC COMMENT PERIOD AND
COMMENT RESPONSES

The following was the only comment submitted in writing during the public availability held on
September 14, 1998 at the Virginia Air and Space Center located in Hampton, Virginia:

Comment 1: The commenter suggested that NASA look into the possibilities of bioremediation and
provided the name of a company who specializes in bioremediation. Also, the commenter noted that
she is interested in the most environmentally correct method of handling the problem at Tabbs
Creek and added her concern that by depositing the contaminated sediments into a landfill NASA

-------
was postponing the problem to a later date.

Response 1: The company recommended by the commenter was contacted. This company has no previous
experience in bioremediating sediments contaminated with PCBs. In fact, staff members of NASA,
VDEQ and EPA were consulted on this topic and to the best of their knowledge, remediation of
contaminated sediments through bioremediation has not been successfully proven as effective.
NASA, EPA and VDEQ are also interested in handling the contaminated sediment at Tabbs Creek in
the most environmentally correct manner and feel that disposal in a TSCA approved landfill
achieves this. TSCA approved landfills, which meet the reguirements of 40 C.F.R. 761.75, are
carefully designed to contain PCB waste(s). Among other things, they have multiple impermeable
liners to prevent leaks and groundwater monitoring systems to detect leaks immediately in the
unlikely event that they occur. Although the dewatered PCB contaminated sediment will not be
treated, NASA, EPA and VDEQ feel that disposal in a TSCA-approved landfill this will be
protective of human health and the environment.

XIII. REFERENCES

Ebasco Services Incorporated, 1991. Final Work Plan for Tabbs Creek Remedial
Investigation/Feasibility Study for Langley Research Center. Hampton, Virginia. April.

Ebasco Services Incorporated, 1993. Final Engineering Assessment of PCB/PCT in Storm Sewers.
Langley Research Center. Hampton, Virginia. April.

Foster Wheeler Environmental Corporation, 1998. Final Remedial Investigation for Tabbs Creek.
Langley Research Center, Hampton, Virginia. May.

Foster Wheeler Enviromental Corporation, 1998. Feasibility Study for Tabbs Creek, Langley
Research Center, Hampton, Virginia. February.

Gallagher, K., et al., 1992. Bioaccumulation of Polychlorinated Terphenyls by Aguatic Biota of
an Estuarine Creek. College of William and Mary, Virginia Institute of Marine Sciences. Draft.

Hale, R.C., 1990a. Letter from R. Hale to C.A. Lunsford providing data on the calculated
concentration of PCBs/PCTs in oysters (January 16).

Hale, R.C., 1990b. Novel Chlorinated Terphenyls in Sediments and Shellfish of an Estuarine
Environment. Environmental Science and Technology. 24:1727-1731.

National Aeronautics and Space Administration (NASA, 1990. Letter from J.W. Lee, NASA, to S.
Turner, Ebasco Services Incorporated, transmitting the Bionetics analytical results reported
November 1989. January 11.

U.S. Air Force, 1982. Installiation Restoration Program for Langley AFB, Virginia: Phase II -
Field Evaluation. Prepared for Langley Air Force Base by Water & Air Research, Inc. August.

U.S. Environmental Protection Agency (EPA), 1988. Guidance for Conducting Remedial
Investigations and Feasibility Studies Under CERCLA, Interim Final. Office of Solid waste
and Emergency Response (OSWER) Directive, 9355.3-01, EPA/540/G-89/004.

U.S. Environmental Protection Agency (USEPA), 1989. Risk Assessment Guidance for Superfund
Volume I Human Health Evaluation Manual (Part A). Interim Final. December.

U.S. Environmental Protection Agency (USEPA), 1991. Site Analysis for NASA Langley Research
Center/Langley AFB, Hampton, Virginia. October.

-------
                           APPENDIX A
                            FIGURES

980650
98065D>
98065E>
98065F>
98065G>
98065H>
98065I>
98065J>
98065K>
                               APPENDIX C

                   APPLICABLE OR RELEVANT AND APPROPRIATE
                              REQUIREMENTS
                                 APPENDIX B

                                   TABLES

                                  Table 2
                      Results of RME Risk Estimates
Receptor
                           Cancer Risk
                            Total Risk
                                                   Noncancer Risk
                                                    Hazard Index
Future Use Scenarios
Future Youth Trespassers
Sewer Maintenance Worker
                            9.3x10 -5
                            2.2x10 -6
                                                       0.053
                                                       0.0026
Harvesters & Hunters
Crab Harvesters
Oyster Harvesters
Hunters
                            7.7x10 -4
                            4.9x10 -4
                            4.1x10 -4
                                                       0.081
                                                       0.053
                                                       0.044
Biota Consumers
Adult Crab Consumer
Youth Crab Consumer
Adult Fish Consumer
Youth Fish Consumer
Adult Oyster Consumer
Youth Oyster Consumer
                            5.8x10 -3
                            1.9x10 -4
                            6.6x10 -4
                            1.8x10 -5
                            6.3x10 -4
                            5.1x10 -5
                                                       2.8
                                                       0.47
                                                       0.39
                                                       0.054
                                                       1.9
                                                       0.77

-------
                                            Table 3
                        Volume of Contaminated Sediment Calculations
                                                                    Proposed
Section
A
B
C
D
E
F
G
H
I
J
K
Length (ft)
150
180
480
100
100
500
60
60
100
100
100
Total Width
Including Buffer (ft)
20
40
30
30
10
40
40
20
15
40
10
Area (ft 2)
3,000
7,200
14,400
3,000
1,000
20,000
2,400
1,200
1,500
4,000
1,000
Excavation Depth
(ft)
4
4
2
2
4
0.5
2
0.5
0.5
4
4
Volume
(ft 3)
12,000
28,000
28,000
6,000
4,000
10,000
4,800
600
750
16,000
4,000
Total Area = 58,700 ft 2
or = 1.4 Acres
Total Volume = 115,750 ft 3
or = 4,300 yd 3

-------
Implementability
Institutional
Controls
Low capital
and O&M.
Warning Signs/Public
Meetings
Effective in informing workers and public of risks on
site. No contaminant reduction.
Easily implemented.
Low capital and
O&M.
Easily implemented.
Low capital,
medium O&M.
Capping
Non-RCRA Cap
Effective in preventing direct contact and sediment
migration. Susceptible to erosion. No reduction in
TMV (through treatment).
Easily implemented. Would destroy wetlands
Reliability a problem because of flooding.
Low capital,
low O&M.
Effective in minimi zing infiltration and preventing
direct contact. No reduction in TMV (through
treatment).
Would destroy wetlands if installed in a marsh
area. Requires stable sub-base after sediment
dewatering. Reliability a problem because of
flooding.
High capital
and O&M.
Effective in removing contaminated soil and
sediment. Waste requires further processing to
achieve remedial obj ectives.
Use commercially available equipment.
Accessibility is a problem. Requires Section 404
permit.
Dredging
Effective in removing sediments. Waste requires
further processing to achieve remedial objectives
Resuspension of sediment is a concern.
Commercial facilities are available. Requires
Section 404 permit.
High capital,
no O&M.
Solidification/
Stabilization
Effective in stabili zing PCB-contaminated soil and
sediment. Treatability study required to determine
proper formula. Process could be reversed under
adverse conditions such as low pH.
Soil Washing
Limited experience. No commercial system
exists

-------
Chemical
Treatment
Process Option

Dechlorination (KPEG)
Effectiveness in destruction of PCBs. Limited
experience in treating PCB-contaminated solids
Implementability
Limited experience, especially in treating solids. Can
be used with Anaerobic Thermal Processor (ATP)
system.
Thermal
Off-site: High
capital, no O&M.
On-site: Medium
capital, no O&M.
Low-temperature
Thermal Desorption
Only a few commercial units are available. Small waste
volume is not cost-effective to be treated on-site.
Medium capital,
no O&M.
Vitri fication
Medium capital,
low O&M.
Effective in removal of PCBs from sediment.
Limited experience. One mobile unit has been
manufactured.
Medium capital.
Thermal Gas Phase
Reduction
A demonstration scale unit was effective in
removal of PCBs and their destruction.
Only a pilot-scale unit is available. A full scale unit
scheduled for 1994.
Medium capital.
In-Situ
Treatment
Effectiveness is a concern when performing
underwater. Treatability study required to
determine proper formula. Process could be
reversed under adverse conditions such as low pH.
Commercial facilities are available. Long distance for
transportation.
Medium capital,
no O&M.
On-site Backfill
Easily implemented.

-------
Alternative 1
No Action
Description:
Alternative 2
Dredging/Off-Site Incineration
Dredge, dewater, and transport
contaminated sediment off-site for
incineration in a TSCA-approved
facility. Backfill excavated area and
restore to a wetland. Ban fishing and
crabbing in Tabbs Creek for five years.
Page 1 of 2
Dredge and dewater contaminated
sediment and dispose off-site in a TSCA
landfill. Backfill excavated area and
restore to a wetland. Ban fishing and
crabbing in Tabbs Creek for five years.
Little risk to human health from direct
contact. High risks from ingestion of
contaminated biota. Chronic stress to
biota. No disturbance of wetlands.
Protects human health and the
environment. Site contaminants removed
removed and treated. Clean sediment
cover eliminates future contact of any
remaining contaminants with biota.
Restoration of destroyed wetland
requires a long time.
Protects human health and the
environment. Site contaminants removed
and backfilled. Clean sediment cover
eliminates future contact of any
remaining contaminants with biota.
Restoration of destroyed wetland
requires a long time.
There are no ARARs for PCBs in
sediment.
Long-Term Effectiveness:

Not effective in reducing impact to
environment and risk from ingestion
of biota. Long-term monitoring
required.
Would comply with TSCA and clean-
up goals, AWQC, location of the
treatment facility would be located in
100-year floodplain.
Effective in eliminating risk by
removing source of contamination to
biota and surface water. Wetland
would be reestablished and restored
over time. Ban on fishing and crabbing
would reduce exposure to
contaminated biota. Incineration is
irreversible and is reliable.
Would comply with TSCA and clean-up
goals, AWQC, location-and-treatment
facility would be located in 100-year
floodplain.
Effective in eliminating risk by removing
source of contamination to biota and
surface water. Wetland would be
reestablished and restored over time. Ban
on fishing and crabbing would reduce
exposure to contaminated biota.
Landfilling is reliable i f managed
properly.

-------
Alternative 1
No Action

Reduction of Toxicity, Mobility, or
Volume through Treatment:
Alternative 2
Dredging/Off-Site Incineration
Removal and treatment of sediment
would reduce toxicity, mobility, and
volume of contaminants. Treatment
process is not reversible.
No reduction in toxicity, mobility or
volume through treatment. Removal and
containment of sediment would reduce
mobility of contaminants. Toxicity and
volume would be unchanged.
Short-Term Effectiveness:

No remedial action implemented.
No disturbance of the wetland.
Monitoring program would not pose
risk to workers or community.
Implementability:

Long-term monitoring can be
implemented with no difficulty.
Achieves remedial objectives in 12
months. Risks to public or workers
during remediation from dust and
transport off site. Workers would be
required to wear protective equipment.
Measures required to protect public and
workers from dust during dredging and
material handling. The wetland and
floodplain would be impacted during
dredging prior ot backfilling.
Fishing and crabbing ban can be
implemented by NASA, state, and local
officials. Dredging and off-site
incineration is common construction and
commercially available. Wetland
restoration has not been demonstrated
and may pose difficulties.
Approximately eight months would be
required to dredge, dewater, and
transport sediment to off-site incineration
facility.
Achieves remedial action objectives in
12 months. Risks to public or workers
during remediation from dust and
transport off site. Workers would be
required to wear protective equipment.
Measures required to protect public and
workers from dust during dredging and
material handling. The wetland and
floodplain would be impacted during
dredging prior to backfilling.
Fishing and crabbing ban can be
implemented by NASA, state, and local
officials. Dredging and off-site
incineration is common construction and
commercially available. Wetland
restoration has not been demonstrated
and may pose difficulties.
Approximately eight months would be
required to dredge, dewater, and
transport sediment to off-site landfill.
Cost
Capital:
Annual O&M:
Five-Year Review Cost:
Present Worth:
Capital:
Annual O&M:
3-Year Evaluation Cost:
Present Worth:
Capital:
Annual O&M:
3-Year Evaluation Cost:
Present Worth:

-------
Regulatory
  Level
                                        Table 6

                  Chemical-specific ARARs,  Criteria,  and Guidance

                       ARAR Identification                Status
                                                                     Requirement Synopsis
                                                                  Action to be Taken to
                                                                  Attain ARARs
Federal
Federal
State
CWA National Ambient Water                Relevant
Quality Criteria  (NAWQC) for                and
Protection of Human Health and          Appropriate
Aquatic Life
Toxic Substances Control Act               To Be
(TSCA) ,  40 CFR, Part 761, Subpart       Considered
G; PCB Spill Cleanup Policy

Virginia Water Quality Standards for    Applicable
Surface Water  (9 VAC 25-260-5 to
550)
Containment levels regulated by NAWQC are
provided to protect human health from exposure from
ingestion of unsafe drinking water, and/or from
consuming aquatic organisms (primarily fish); and to
protect aquatic organisms.

Provides soil cleanup levels for low/high
concentrations spills and restricted/non-restricted areas.
Quality criteria are provided to maintain surface water
of satisfactory quality, be consistent with public health
and recreational purposes, enhance the propagation
and protection of fish and aquatic life, and advocate
other beneficial uses of the water.
Activities that could impact
surface water will comply
with the promulgated values.
The cleanup levels will be
considered for the site.
The promulgated values will
be considered in determining
the discharge limit from the
remedial treatment facility.
                                                                        All state waters shall be maintained at such quality as
                                                                        will permit all reasonable and beneficial uses and will
                                                                        support the propagation and growth of all aquatic life,
                                                                        including game fish,  which might reasonably be
                                                                        expected to inhabit them. Reasonable beneficial uses
                                                                        include, but are not limited to, recreational uses  (e.g.,
                                                                        swimming and boating)  and production of edible and
                                                                        marketable natural resources (e.g.,  fish and shellfish).

-------
                                                                                                                                                            Page  1  of  3
Regulatory
  Level
                   ARAR  Identification
                                                                                                                                    Action to be Taken to Attain  ARARs
  Federal
   (Non-
Regulatory
                                                Applicable Federal  agencies  are required to reduce the risk of  flood  The  potential effects of the remedy will  be  evaluated and
                                                           loss, to minimi ze impact of floods,  and to restore and      addressed to ensure that the planning  and decision-making
                                                           preserve the  natural and beneficial values of floodplains.  reflect consideration of flood hazards and floodplains
                                                                                                                          management, including restoration and preservation of natural,
                                                                                                                          undeveloped floodplains.
                                               Applicable  Federal  agencies  are required to minimi ze the destruction,  The  portion of the remedy that involves  constructiont will
                                                           loss, or degradation of wetlands and to preserve and        include all practicable means of minimi zing  harm to wetlands
                                                           enhance  natural and beneficial values of wetlands.          Wetlands protection considerations will  be incorporated into the
                                                                                                                                       remedial design.
              Fish and Wildlife  Coordination
              Act
               (16 USC 661)
                                                Applicable This regulation  requires that any Federal agency that
                                                           purposes  to  modi fy a body of water must consult with the
                                                           U.S. Fish and  Wildlife Services (USFWS). This
                                                           requirement  is addressed under CWA Section 404
                                                           requirements .
 During the remedial  design,  the effects on streams and wetlands
will be evaluated and addressed. If an alternative modi fies a
body of water or potentially affects fish or wildli fe, EPA must
consult the USFWS.
                                                Applicable The Fish  and Wildli fe Conservation Act  ( or non-Game Act )
                                                           addresses the  conservation of no n- game wildlife  species
                                                           through the establishment of State conservation  plans.  The
                                                           No n- Game  act is  administered by the USFWS, which
                                                           encourages States  to consult with the National Marine
                                                           Fisheries Service  (NMFS )  and the Department of
                                                           Commerce  regarding marine species . After the State ' s
                                                           conservation program has  been approved by the FWS, it  is
                                                           eligible  for 75% reimbursement on no n- game pro j ect s .
                                                           Essentially, the Act provides Federal funding for wildli fe
                                                           conservation activities conducted by the States. This  Act
                                                           applies to proposed  impoundments , diversions, dredging,
                                                           control ing or  modi fying surface waters , requiring  EPA  to
                                                           noti fy various Federal agencies of the proposed  actions .
                                                                                                                                           squires that the
                                                                                                                                        (freshwater), NMFS
                                                                                                                         agency responsible for administerin
                                                                                                                         resources of the State.
                                                                                                                         the
                                     proj ect must be coordinated
                                    (marine),  and the State
                                   _^ng the fish and wildlife
                          Prior to undertaking the remedial action
     project will be  coordinated with the USFWS, NMFS, and
 the Virginia Department  of  Game and Inland Fisheries  (DGIF)
 regarding any activities to be undertaken in water bodies at the
 proj ect site. This coordination could be undertaken as part of  the
 application process  for  a U.S. Army Corps of Engineers
 (ACOE)  Section  404 permit for any dredging or filling of water
 bodies or wetlands required for the proj ect.  Then, the ACOE
 would incorporate the  recommendations of the fish and wildli fe
 agencies into the condition of any Section 404 permit
 the proj ect.

-------
 Regulatory       ARAR Identification            Status                       Requirement Synopsis                                      Action to be Taken to Attain ARARs

  Level

Federal        The EPA 404(b)(Cl)             Applicable      Under this  requirement,  no activity that adversely affects  a     During the remedial design the effects  on  wetlands will be
               Guidelines  for  Specifications of              wetland  shall  be permitted i f a practicable alternative  that     evaluated and addressed. Permits may be required for some
               Disposal  Site  for  Dredged or Fill             haslesseffectis  available.  If there is no other practicable   alternatives.
               Material(40CFR  230)                            alternative, impacts  must be mitigated.

               Endangered  Species Act of 1973  Applicable   Certain species of fish  and wildli fe are identified as being  The potential effects of the remedy will  be  evaluated and
                                                             threatened with extinction and are entitled to special
                                                             preservation  and protection under these statutes.

                                                Applicable  This regulation  outlines  the requirements for constructing a    The remedy will be designed, constructed,  operated,  and
                                                            RCRA facility  on a 100-year floodplain.                          maintained to prevent washout of any hazardous  waste by a
                                                                                                                             100-year flood, unless waste may be removed safely before
                                                                                                                                floodwater can reach the facility or no adverse effects on
                                                                                                                                     human health or the environment would result if washout
                                                                                                                                     occurred.

-------
                                                              Table  7  (Continued)
                                              Location-sped fie ARARs,  Criteria,  and Guidance
                                                                                                                                                                                            Page
 Chesapeake Bay  Preservation Act,  Code of       Applicable
 Virginia Sections  10.1-2100 et.  seq. ;
 Chesapeake Bay  Preservation Act
 Designation and Management  Regulations
 (CBPA Regulations)(9 VAC  10-20-10 to  280)
 Virginia Board of  Game  and Inland Fisheries,
 Code of Virginia Sections  29.1-100 et.  seq.;
 Virginia Endangered  Species Act,  Code of
 Virginia Sections  29.1-563 et.  seq.;  Virginia
 Endangered Species Regulations  (VA 325-01-
1/4VAC 15-20-130 et.  seq.;  Virginia Natural
Area Preserves Act  (VNAPA)  Code  of
Virginia Sections 10.1-209  et.  seq.;  Endangered
Plant and Species Act, Code of Virginia
sections 3.1-1020 et.  seq.;  Endangered Plant
and Insect Species  Regulations  (VR 115-04-
01/2VAC 5-320-10).
Applicable
                                                 Applicable
Requires that certain  locally designated tidal and
nontidal wetlands,  as  well  as other sensitive land areas,
be subj ect to limitations regarding land-
disturbing activities,  removal of vegetation, use of
impervious cover, erosion and sediment control,
stormwater management,  and  other aspects of land use
that may have effects  on water quality.

Assessments should  be  deducted and submitted to the
Virginia Department  of Environmental Quality
(VDEQ) for review by the Department of Game and
Inland Fisheries  (VDEQ Department of Conservation
 and Recreation  (OCR),  and  Department of Agriculture
 and Consumer Services (DACS).
                                                                                  During the remedial design-,  the  effects on wetlands
                                                                                  and water quality will be evaluated and addressed.
                    These  regulations delineate the procedures and
                    requirements to be followed in connection with
                    activities  such as dredging, filling or discharging  any
                    pollutant into, or adjacent to, surface waters,  or any
                    activity which impacts the physical, chemical or
                    biological  properties of surface waters  (The definition
                    of  surface  waters includes wetlands). The standards  are
                    typically required in addition to the U.S. Army  Corps  of
                    Engineers Section 404 permit,  and are established in
                    coordination with requirements of the Chesapeake Bay
                     Preservation Act Administered by local permitting
                     boards  or  requirements of the Virginia Marine
                     Resources  Commision.
DGIF, DCP, and DACS will  determine whether any
ecological significant  areas  supporting natural heritage
Resources, any rare,  or endangered animal
species, endangered plant or  insect species or their
 habitat(s)  are threatened by the contamination and/or
remediation of the  site.  Certain species of plants
and/or insects, as well as certain species of fish and
wildli fe are identi fied as being rare,  threatened or
endangered and are  entitled to special  preservation
and protection measures under these statutes.
                                                               The  requirements will be complied with during  the
                                                               developement  of the remedial design and
                                                               implementation of the remedial action.

-------
                                                                                                               Table  8
                                                                                      Action-Sped fie ARARs for Sediment  and Surface Water Page

                                                                                            Requirement Synopsis

                                                                                       A.  COMMON TO ALL ALTERNATIVES
Occupational  Safety and  Health  Act
(OSHA)-General Industry Standards
(29 CFR 1910)
Applicable
These regulations  specify an  8-hour time-weighted average
 concentratim  for  worker  exposure to various organic com-
pounds . Training requirements for workers at hazardous
waste operations are  sped fied  in 29 CFR 1919.120
                                                  Applicable
                                                  Applicable
                        This  regulation outlines the recordkeeping  and  reporting
                        requirements for an employer under OSHA.
                                                                       These  regulations apply to the company(ies)  contracted
                                                                       to  install,  operate,  and maintain the treatment  unit.
                                                                          The  standards apply to owners or operators  of  the  facilities
                                                                          which  treat,  store, or dispose of hazardous waste.  The
                                                                          standards apply to all treatment, storage,  or  disposal of
                                                                          hazardouse waste at these facilities.
                                                                                              All workers will be  properly trained.  Safety and
                                                                                              communication equipment  will be installed at the site.
                                                                                              Local authorities will be  familiar!zed with the site. Plans
                                                                                              will be developed and implemented during remedial.
                                                                                              design. Copies of the plans  will be kept on-site.
                                                                                                                                                Below 1 pp:
                                                                                                  B. OFF-SITE DISPOSAL
      Waste Transportation
Department of Transportation  (DOT)
Rules for Transportation  of
Hazardous Materials  (49 CFR Parts
171,172,177,179)
Applicable
                                                  Applicable
This regulation outlines  procedures for the packaging,
labeling, mani testing,  and transporting of hazardous
materials.
                        This  regulation establishes the responsibility of  generators,
                        transporters,  and disposers of PCB waste  in  the handling,
                        transportation, and management of the waste.  Requires  a
                        mani fest  and record-keeping.

-------
                                                                                           Table  8  (Continued)
                                                                          Action-Sped fie ARARs  for  Sediment and Surface Water
                                                                                            Requirement  of Synopsis

                                                                                        3. OFF-SITE  DISPOSAL (continued)
    Waste Transportation  (continued)
VHWMR-Hazardous Waste  Management
Regulations  (VR 672-10-1),  July 1,  1991
Applicable
   The Virginia  Department  of Environmental Quality has  adopted
   certain DOT regulations  governing the transport of hazardous
   materials.
This regulation will be  applicable to any company contracted  to
transport hazardous material  from the site.
                                                 Applicable
                                                                       The National Pollulant Discharge  Elimination System  (NPDES)
                                                                       permit requirements  for point  soisme discharges must be met,
                                                                       including the NPDES  Best Management  Practice Program. These
                                                                       regulations include, but are not  limited to, requirements  for
                                                                       compliance with water quality  standards,  a discharge monitoring
                                                                       system, and records  maintenance.
                                                                                          Proj ect will  meet  NPDES permit requirements  for  point  source
                                                                                          discharges.
                                                                                                                                                                    ted with the  USFWS,  	  _
                                                                                                                                                                         nd Inland  Fisheries (DGIF)
                                                                        Proj ect must be coordina
                                                                        Virginia Department of Game  a
                                                                        regarding any activities  to  be  undertaken _LII wauej_ JJOLI
                                                                        project site. This coordination could be undertaken as
                                                                        application process for a U.S.  Army Corps of Engineer^
                                                                        n\r'rM? \  c-ction 404 permit
                                                                                                                                                            tivities
                                                                                                                                                          This coordination could  be  undertaken as part of the
                                                                                                                                                                for a U.S. Army  Corps
                                                                                                                                                                      for any dredging  or filling
                                                                                                                                                                       1  "           '   '    "    by the ACOE
                                                                                             ____
                                                                                           (ACOE)  Secon     perm    or any  regng or       ng o  waer
                                                                                          bodies  or  wetlands required for the project, whereby the ACOE
                                                                                          would incorporate the recommendations of the fish  and wildli fe
                                                                                                             condions of any Section 404  permit issued
                                                                                                                                            agencies into
                                                                                                                                            for  the Project.
Virginia Department  of  Environmental
Quality  (DEQ)(9 VAC  25-31-10 to 940)
Permit Regulation  [Virginia Pollutant
Discharge Elimination  Sytem (VPDES)
and Virginia  Pollution  Abatement (VPA)
Permit Program]),  Adopted March 28-29,
1982
Applicable
The permit governs  the  discharge of any pollutant, including            The remedy shall comply with  all  EPA toxic effluent standards
sewage, industial wastes,  or other wastes, into or adjacent to  State   and prohibitions promulgated  under the Act within the time
waters that may  alter the  physical,  chemical, or biological properties provided by the regulation. All  reasonable steps not to adversely
of State waters, except as author!zed pursuant to a VPDES  or  VPA       affect human health or the  environment shall be taken. Proper
permit.                                                                  operation and maintenance includes effective plant
                                                                         performance; and adequate funding & license operator staffing,
                                                                         and laboratory and process  control,  including appropriate quality
                                                                         assurance procedures.

-------
Table 8 (Continued)
Action-Sped fie ARARs for Sediment and Surface Water Page
ARARs

B. OFF-SITE DISPOSAL (continued)

Disposal

TSCA Chemical Waste Landfill
(40 CFR 761.75)
TSCA PCB Remediation Work
(40 CFR Part 761.61 (b))
TSCA PCB Remediation Waste
(40 CFR Part 761.63)
RCRA Land Disposal Restriction
(40 CFR 268, Subpart D)
Applicable

Applicable

Applicable
Virginia Hazardous Waste Manage Applicable
Regulations (VR 672-10-1/9 VAC 20-60-10
Hazardous Waste Permit Program,
Virginia Solid Waste Management Applicable
Regulations (VSWMR)(9 VAC 20-80-10
to 790)
CAA-National Ambient Air Quality Relevant and
Standards (NAAQS) for Total Suspended Appropriate
Particulates (40 CFR 129, 105, 750)
Requires liquid PCBs at concentrations greater than 500 ppm to be
disposed of in an incinerator or by another technology capable of
providing equal treatment. Liquids at concentrations above 50 ppm
but less than 500 ppm and soils contaminated above 50 ppm may
also be disposed of in a chemical waste landfill.

Requires PCB remediation waste, which term includes the dredged
sediments containing certain amounts of PCBs, to be disposed of in
one of several ways. One permissable disposal method is disposal in
an approved TSCA PCB landfill.
Requires PCBs greater than 50 ppm be disposed of within one year.

After November 8, 1988, movement of excavated materials to a new
location and placement in or on land would trigger land disposal
restrictions (for non-CERCLA actions). CERCLA actions became
regulated under this requirement on November 8, 1990.
Covers the basic permitting, application, monitoring, and reporting
requirements for off-site hazardous waste management facilities.
will include consideration of requirements. Part X.
Virginias program to properly manage solid waste treatments,
storage, or disposal of any solid waste by obtaining a permit. This
includes solid wastes containing PCB concentrations between 1.0
ppm and 50.0 ppm.

C. EXCAVATION AND/OR STABILIZATION

This regulation specifies maximum primary and secondary 24-hour
Concentrations for particulate matter. Fugitive dust emissions from
site excavation activities must be
ary stand
Provides requi
mai
srate waste piles.
Any off-site facility accepting PCB waste from the site must be
properly permitted. Implementation of the alternative will
include consideration of all requirements.
Alternative development will consider disposal requirements.
This requirement shall be met by disposing of dredged, PCB-
containing sediment in an approved TSCA PCB landfill.
Piled, dewatered sediment will meet this requirement.
This regulation may be applied to the disposal of debris off-site
or on-site. PCB concentrations between 1.0 ppm and 50-0 ppm
are restricted to disposal in sanitary landfills or industrial waste
landfills with leachate collection, liners, and appropriate
groundwater monitoring as required in Part V of the VSWMR.
Piled, dewatered sediment will meet this requirement.
Requires owner/opetator to control wind dispersal of particulate
matter.

-------
                                          Applicable
                                                                                         Table 8  (Continued)
                                                                         Action-Specific ARARs for Sediment and  Surface  Water

                                                                                        Requirement Synopsis

                                                                                                    C. EXCAVATION AND/OR STABILIZATION (continued)

                                                                                                                                            Same as above.
                                          Applicable
                                                                                  If required, the equired documentation  will  be submitted to
                                                                                  ACOE to obtain its approval  for  dredging and filling.
                                          Applicable
Required to meet EPA  guidelines  for the 404 Permit Program to
place fill material or  dredge  and backfill in the tidal wetlands.
Virginia Air Pollution  Control  Law,  Code Applicable
of Virginia Sections  10.1-1300  et.  seq. ;
Virginia Department of  Air  Pollution
Control, Regulations  for  the  Control and
Abatement of Air  Pollution  (9 VAC 5-50-
60 to 230)

Virginia Erosion  and  Sediment Control    Applicable
Law, code of Virginia Sections  10.1-560  et.
seq.; and the Virginia  Erosion  and
Sediment Control  Regulations  (VR 625-
02-00/4 VAC 50-30-10  to 110)

                                          Applicable
Wetlands Mitigation  Compensation Policy  Applicable
Virginia Water
Protection Permit  Regulations  (9 VAC 25-
210-10 to 260)
The Virginia Department  of  Air Pollution Control's emissions
standards must be met with  regard to the potential release of toxic
pollutants subj ect to the Department's standards that we released
due to remedial activities  at  a site.  Also,  any disturbance of  surface
or underlying soil at a  site,  or treatment of soil or water must met  the
Air Boards standards  for particulate emmisions to the air.

Outlines Virginia Erosion and  Sediment Control Law and                           Recommended practices will be  followed during excavation,
Regulations and practices to minimi ze  erosion.                                   NO "land disturbing" activity,  as  governed by the State statute
                                                                                  or a local erosion and sediment  control ordinance,  may take
                                                                                  place until an erosion and sediment  control plan for the activity
                                                                                  has been submitted and approved  by the proper authority

Requires State agencies  and local stormwater management programs
to maintain post-development runoff characteristics; controls non-
point source pollution,  establishes acceptable administrative
procedures; requires  stormwater management facilities,; provides for
interpretation of stormwater management programs with erosion and
sediment control, and other land development-related programs;  and
reviews and evaluates local management programs.

These regulations delineate the procedures and requirements to  be
followed in connection with activities such as dredging, filling or
discharging any pollutant into,  or adjacent to, surface waters, or any
activity which impacts the  physical, chemical, or biological
properties of surface waters.

Requires that reasonable and good faith effort be made to identi fy                 Activities impacting resources governed by these  statutes must
and evaluate historic properties, to assess to assess the project's effects  when  comply with state requirements.
historic properties are  found,  and to  offer the Virginia Department of
Historic Resources an opportunity to comment on the affected
property when it is either  listed or eligible for listing on the National
Register of Historic  Places.
Remedial activities will  comply with substantive requirements.(4 VAC  20-390-  to 50),
No permits will be required.

-------
APPENDIX C

GLOSSARY

Glossary of Terms

Amphipod: Any of various small crustaceans.

Aquifer: A saturated, permeable geologic formation or structure that is capable of yielding
water in usable quantities under ordinary hydraulic gradients.

Benthic Invertebrate: A form of animal life that is found on or near the bottom of a stream,
lake, ocean or other water body.

Bioaccumulation: An increase in concentration in living organisms as they take in contaminated
air, water, or food because the substances are very slowly metabolized or excreted.

Bioavailability: A general term to describe the accessibility of contaminants to ecological
populations. Bioavailabilty consists of: 1) a physical aspect related to phase distribution and
mass transfer, and 2) a physiological aspect related to the suitability of the contaminant as a
substance.

Biodegradation: 1) The reduction in concentration of a chemical or physical agent through
naturally occurring microbial activity. 2) The process of an organic molecule becoming
transformed by biological means.

Downgadient: The direction that groundwater flows similar to "downstream" for surface water.

Endpoints of Concern: Conclusions that can be drawn from an investigation.

Fate and Transport: Includes the tendency for a chemical to migrate through the environment and
the degree to which a chemical remains unaltered in the environment.

Feasibility Study (FS): Report that summarizes the development and analysis of remedial
alternatives considered for the cleanup of CERCLA sites.

Groundwater: The supply of fresh water found beneath the Earth's surface in the interstices
between soil grains, in fractures, or in porous formations.

Leachate: Water that collects contaminants as it trickles through wastes, pesticides or
fertilizers. Leaching may occur in farming areas, feedlots, and landfills, and may result in
hazardous substance entering surface water, groundwater or soil.

Polychaete worm: The most numerous marine form of the Phylum Annelida (segmented worms). They
vary widely in body shape, but almost all are clearly segmented externally and have bristles or
setae. Many are conventionally "worm like" with dozens or hundreds of segments. There are both
mobile (pelagic) and sessile (tube) forms. Feeding mechanisms have evolved to form jaws;
filters; mouth parts for licking, sucking, and piercing; and indiscriminant ingestion of
mud/sand.

Receptors: Any living organism or environmental medium which is exposed to contamination's from
a discharge.

Remedial Action: Implementation of plans and specifications, developed as part of the design, to

-------
remediate site.

Remedial Investigation  (RI):  The RI is prepared to report the type, extent and potential for
transport of constituents of potential concern at a hazardous waste site, and directs the types
of cleanup options that are developed in the FS.
Semi-volatiltes:  Compounds that do not readily volatilize at standard temperature and pressure.
Compounds that are amenable to analysis by extraction if the sample with an organic solvent.

Target Analyte List: A standard list of metals to analyze in samples.

Trophic transfers: The amount of material  (usually measured in terms of energy or matter
[i.e. contamination]) that passes from step to step in the food chain (i.e. herbivore to
carnivore to higher carnivore).  Each of these steps is called a trophic level.

Volatilization: To evaporate or cause to evaporate.

-------