PB99-963904
EPA541-R99-008
1999
EPA Superfund
Record of Decision:
Langley Air Force Base
NASA Langley Center OU 47
Hampton, VA
1/14/1999
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RECORD OF DECISION
LANGLEY AIR FORCE BASE
OPERABLE UNIT 47 (OT-51)
DECLARATION
SITE NAME AND LOCATION
Langley Air Force Base
Operable Unit 47 (Installation Restoration Program [IRP] Site OT-51)
Hampton, Virginia
STATEMENT OF BASIS AND PURPOSE
This Record of Decision (ROD) presents the selected remedial action for IRP Site OT-51,
designated Operable Unit (OU)-47, at Langley Air Force Base (AFB) in Hampton, Virginia (the
"Site'O, chosen in accordance with the Comprehensive Environmental Response, Compensation,
and Liability Act (CERCLA) of 1980, as amended, 42 U.S.C. §§ 9601-9675 and, to the extent
practicable, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), 40
Code of Federal Regulations 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.
DESCRIPTION OF THE SELECTED REMEDY
OU-47 is part of a comprehensive environmental investigation and cleanup currently being
performed at Langley AFB under the CERCLA program. This ROD addresses only OU-47; the
other OUs located at Langley AFB are being investigated separately under its Installation
Restoration Program and will be addressed in future RODs. Also, this ROD addresses only soil
at the OU. The groundwater is being treated as a separate OU and will be addressed on an
installation-wide basis.
Langley AFB, the U.S. Environmental Protection Agency, and the VDEQ have determined that
No Action is necessary for this site. Risk assessment results indicate that OU-47 soils do not
pose an imminent or substantial danger to public health, welfare, or the environment
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DECLARATION OF STATUTORY DETERMINATIONS
Risk assessment results from the remedial investigation (RI) performed at the OU indicate that
No Action is necessary to be protective of human health and the environment.
4-
THOMAS J. KECK' Date
Lieutenant General, USAF
Vice Commander, Air Combat Command
ABRAHAM FERDAS' Date
Director
Hazardous Site Cleanup Division
U.S. Environmental Protection Agency
Region III
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RECORD OF DECISION
LANGLEY AIR FORCE BASE
OPERABLE UNIT 47
December 1998
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TABLE OF CONTENTS
Section Page
I. Site Name, Location, and Description 1
H. Site History 2
m Highlights of Community Participation 3
IV. Scope and Role of Operable Unit 4
V. Summary of Site Characteristics and Extent of Contamination 5
VI. Current and Potential Future Site and Resource Uses 8
VH. Summary of Site Risks 8
Vin. Significant Changes from Proposed Plan 12
DC. Responsiveness Summary 12
X. References 15
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APPENDIX A
Table Title
1 Summary of Operable Units Under CERCLA Investigation
2 Variables Used to Estimate Potential Chemical Intakes and Contact Rates for
Receptors at IRP Site OT-51 (OU-47)
3 Summary of Site-Related RME Cancer Risk and Noncancer Hazard for IRP Site
OT-51 (OU-47)
APPENDIX B
Figure Title
1 Langley AFB Vicinity Map
2 Base Map of Langley AFB Showing the Location of IRP Site OT-51 (OU-47)
3 Focused RI Sampling Locations
4 Surface Soil Analytical Results Above Screening
Levels (December 1997)
Subsurface Soil Analytical Results Above Screening
Levels (December 1997)
APPENDIX C
Glossary
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List of Acronyms
AFB Air Force Base
bgs below ground surface
BLRA baseline risk assessment
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
COPC chemicals of potential concern
COPEC constituents of potential environmental concern
°F degrees Fahrenheit
DOD U.S. Department of Defense
EPA U.S. Environmental Protection Agency
HI hazard index
IRA interim removal action
IRP Installation Restoration Program
msl mean sea level
NCP National Oil and Hazardous Substances Pollution Contingency Plan
NPL National Priorities List
OU Operable Unit
PCB polychlorinated biphenyl
ppm part(s) per million
PRG preliminary remediation goals
RI remedial investigation
ROD Record of Decision
RME Reasonable Maximum Exposure
SI site inspection
VDEQ Virginia Department of Environmental Quality
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RECORD OF DECISION
LANGLEY AIR FORCE BASE
OPERABLE UNIT 47 (OT-51)
DECISION SUMMARY
I. Site Name. Location, and Description
Langley Air Force Base (AFB) is an active U.S. Department of Defense (DOD) installation
located approximately 180 miles south of Washington, DC, and is part of the Norfolk
metropolitan area (Figure 1). The Base sits on a peninsula bounded by the northwest and
southwest branches of the Back River, which is a tributary of the Chesapeake Bay. In addition to
the 3,152-acre Base installation, Langley AFB supports the 284-acre Bethel Manor Off-Base
Housing Area. Langley AFB was proposed to be included on the National Priorities List (NPL)
in 1993 and finalized in 1994. This list includes sites where uncontrolled hazardous substance
releases may potentially present serious threats to human health and the environment. OU-47
was one of the Installation Restoration Program (IRP) sites investigated under Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA) at Langley AFB and was
initially designated IRP Site OT-51.
Operable Unit (OU)-47 is located at the intersection of Nealy Avenue and Burrell Street, in the
southern part of the Base (Figures 2 and 3). The abandoned electrical substation that formerly
occupied OU-47 was situated in a grassy field north of a boiler station (Building 80), and
southeast of a storm sewer lift station and power distribution equipment. Base dormitory
housing lies directly across Burrell Street from OU-47 and the Temporary Living Facility is
approximately 800 feet southwest of the OU. OU-47 covers approximately 0.08 acre and is
approximately 800 feet northwest of the Back River. Current land use at OU-47 is categorized as
inactive industrial and is expected to remain industrial in the future. Transformer oil spillage
from the electrical substation at OU-47 is believed responsible for polychlorinated biphenyl
(PCB) contamination in soil.
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II. Site History
This section describes the history of OU-47 and regulatory activities conducted to date.
A. OU History
PCB contamination was detected in Langley AFB storm sewers in May 1990. Transformer oil
spillage from the transformers that were formerly located at OU-47 was identified as a potential
source. Surface soil and sediment at OU-47 were investigated in 1990 as part of the subsequent
study of PCB and chlorinated pesticide contamination in Base storm sewers in the Shellbank
Area. Low levels of the PCBs Aroclor 1254 and Aroclor 1260 were detected at concentrations of
up to 1.7 parts per million (ppm) and 1 ppm, respectively. The pesticide DDT and one of its
metabolites, DDE, were detected at levels of 0.64 ppm and 0.39 ppm, respectively. .
B. CERCLA Investigations
Under CERCLA, a site inspection (SI), interim removal action (IRA), and focused remedial
investigation (RI) were conducted at OU-47 from 1993 through 1998. The SI was conducted
from 1993 to 1995 as part of the SI and screening risk assessment for 33 IRP sites.1 This
investigation was performed to assess the presence or absence of contamination at OU-47
resulting from past practices, determine what risks to human health and the environment existed
at OU-47, and determine if further action was necessary for OU-47. The SI identified pesticides,
PCBs, and metals in surface soil and sediment. The SI report recommended further
investigation, to include collection and analysis of groundwater and subsurface soil samples, and
the evaluation of risk to human health and the environment.
The IRA was conducted from April to June of 1997.2 During this activity, the abandoned
substation was demolished and removed, soil adjacent to and beneath the substation was
removed, storm sewer pipe was excavated and replaced, and confirmation soil samples were
collected. Because the soil sample results were below action levels, the excavations were
backfilled with clean material. The IRA ensured that all soil previously identified as
contaminated with pesticides and PCBs was removed.
A focused RI was conducted from December 1997 through April 1998 to further investigate soil
at OU-47, determine groundwater quality, and quantify risk to human health and the
environment.3 Surface and subsurface soil samples were collected, and groundwater samples
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were collected from four monitoring wells installed at the OU. An additional sediment sample
was collected from the storm sewer junction box west of the removed electrical substation to
verify the effectiveness of the IRA. Pesticides and metals were the only constituents detected in
soil during the focused RL The focused RI proved the IRA was effective in reducing
contaminant levels to within U.S. Environmental Protection Agency (EPA) acceptable risk range.
These CERCLA investigations have sufficiently determined the nature and extent of
contamination and have demonstrated that the OU does not pose an unacceptable risk to human
health or the environment.
III. Highlights of Community Participation
In accordance with Sections 113 and 117 of CERCLA, 42 U.S.C. Sections 9613 and 9617,
Langley AFB, in conjunction with the EPA and the Virginia Department of Environmental
Quality (VDEQ), issued a Proposed Plan on September 13, 1998, presenting the preferred
remedial alternative of No Action for OU-47. The Proposed Plan and supporting documentation
were made available for review at that time and are among the documents that comprise the
CERCLA Administrative Record for the Site.
The Administrative Record is available for review by the public at the following information
repositories:
• Hampton Public Library
Reference Section, Langley AFB Information Repository
4207 Victoria Boulevard
Hampton, Virginia 23669
(757)727-1154
• Langley AFB
Administrative Record Room
1CES/CEVR
37 Sweeney Boulevard
Building Number 328
Langley AFB, Virginia 23665-2107
(757) 764-1046
An announcement for a public meeting, the comment period, and the availability of the
Administrative Record for the remedy for OU-47 was published in the Daily Press, a newspaper
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of general circulation in Hampton, Virginia, on September 6, 1998 and in the Flyer, a Langley
Air Force Base newspaper, on September 11 and 18, 1998.
The public comment period for the Proposed Plan was from September 13, 1998 to October 12,
1998. A public meeting was held at the Virginia Air and Space Center in Hampton, Virginia on
September 24,1998 to inform the public of the remedial alternatives and to seek public
comments. At this meeting, representatives from EPA, VDEQ, and the Air Force were available
to answer questions about conditions at the Site and the no action proposal under consideration.
Responses to the comments received during this period are included in the Responsiveness
Summary section of this ROD.
This ROD presents the selected remedial action for OU-47 determined in accordance with
CERCLA, and to the extent practicable, the NCP. 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 Operable Unit
Langley AFB was proposed to be included on the NPL in 1993 and finalized in 1994. This list
includes sites where uncontrolled hazardous substance releases may potentially present serious
threats to human health and the environment. OU-47 is one of the IRP sites currently being
investigated under CERCLA at Langley AFB. Discrete portions of an NPL site are often
managed more effectively as Operable Units. Based on preliminary RI results, the Langley AFB
Tier I Partnership (described below) decided to separate the soil and groundwater at IRP Site OT-
51 into separate OUs. This ROD addresses OU-47, which is the IRP Site OT-51 soil OU. The
remaining OUs at Langley AFB are currently being independently investigated under CERCLA
(Table 1).
Risks to human health and the environment from soil at OU-47 have been evaluated, and this
ROD presents the no action proposal recommended based on risk assessment results. The RI
report, which includes the baseline risk assessment (BLRA), documents the findings associated
with OU-47. On the basis of these findings and the effectiveness of the IRA conducted at OU-
47, Langley AFB, in consultation with EPA and VDEQ, has determined that the Site does not
pose an unacceptable risk to human health and the environment. The risk calculated under the
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current and future land use scenarios is below EPA's acceptable risk range.
Langiey AFB, with the support of EPA and VDEQ, recommends that No Action is necessary at
the Site to protect human health and the environment. Under the No Action alternative, no
remedial action will be taken at OU-47. This is the planned response action for this OU. The
EPA and VDEQ concur with the No Action alternative proposed by Langiey AFB.
This document is the result of a Langiey Partnership Team effort. The Langiey Partnership, the
IRP decision-making body, is composed of representatives from EPA Region 3, VDEQ, the U.S.
Air Force Air Combat Command, Langiey AFB, the U.S. Army Corps of Engineers, and
environmental contractors. Several decisions on how work is to proceed at Langiey AFB have
been made by the team and have been documented. These signed agreements, or "consensus
agreements," are available for review in the Administrative Record.
V. Summary of Site Characteristics and Extent of Contamination
Summarized below are the relevant findings of the work to date with regard to contaminated soil
located within the boundaries of the Site.
A. Site Characteristics
1. Geology
The Site lies within the Atlantic Coastal Plain physiographic province. Ground surface at
Langiey AFB is predominantly flat lying, with most of the Base lying between 5 and 8 feet above
mean sea level (msl). Elevation at OU-47 ranges from about 5 to 6 feet above msl. Drainage in
the region is poor, with numerous saltwater and freshwater marshes located along the major
streams flowing into the Chesapeake Bay. OU-47 is located approximately 800 feet northwest of
the Southwest Branch of the Back River. There are no surface water bodies at OU-47.
The geology of the area around Langiey AFB consists of a thin layer of topsoil overlying fill
materials of varying thickness placed in developed areas and unconsolidated coastal plain
sediments.4 Topsoil is primarily sandy, silty clays or silty, clayey sands deposited within the
flood plains during periods of higher sea level stands or deposited in an estuarine or lagoonal
environment. Fill material includes gravel, rubble, and construction debris, and is similar to
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native materials. The coastal plain sediments were deposited when the area was a submerged
near-shore marine environment.
2. Hydrogeology
Three major groundwater-bearing zones lie beneath Langley AFB. These include the Shallow
Water Table Aquifer between 5 and 100 feet below ground surface (bgs), the Upper Artesian
Aquifer between 100 and 400 feet bgs, and the Principal Artesian Aquifer between 400 and 700
feet bgs. Recently measured groundwater elevations at OU-47 ranged from 2.2 to 3.4 feet above
msl. Even though the groundwater in this area is not used as a source of drinking water,
individual homeowners have groundwater wells that have been used for watering lawns and
washing cars. However, the Shallow Water Table Aquifer provides an important source of
drinking water farther to the west in King Williams, Charles City, New Kent, James City, and
York Counties. In Newport News and Hampton, there are areas where domestic groundwater is
obtained from wells that range from 50 to 100 feet in depth. These wells are probably completed
in the Shallow Water Table Aquifer, which ranges from 5 to 100 feet below land surface.1
Groundwater in the shallow water table aquifer beneath the Base is not used as a source of
drinking water due to high dissolved solids levels and low aquifer yield. Groundwater flow in
this aquifer is slow and flow direction is towards surface water bodies, including the Back River
and its tributaries.
3. Meteorology
Langley AFB has a modified continental-type climate with mild winters.4 During both winter
and summer, temperatures are fairly moderate, with winter temperatures ranging from 4 to 70
degrees Fahrenheit (°F), and summer temperatures ranging from lows of 70°F to highs of mid-
80s °F. Relative humidity varies between 67 and 76 percent, depending on the month.
Prevailing wind direction is from the north during winter and from the south-southwest during
the rest of the year. Precipitation ranges from 24 to 57 inches per year, and is evenly distributed
throughout the year. Maximum precipitation is in July and August, with minimums in November
and April. Average seasonal snowfall in the area is less than 10 inches per year.
4. Ecology
OU-47 presently consists of well-maintained grass lawn. OU-47 is small (0.08 acre) and
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contains no surface water bodies; consequently, ecological habitat is limited and of poor quality.
However, small mammals and passerine birds may forage for seeds and invertebrates at the OU.
5. Soils
Soil at OU-47 consists of a thin layer of topsoil above a 3.5- to 4-foot thick layer of olive and
yellowish brown to dark brown sand and gravel, the uppermost portion of which may be fill
material.3 Underlying the sand and gravel layer is a 4-foot thick layer of olive brown to
yellowish brown fine to silty sand with some clay and traces of gravel. The interval from 8 to 16
feet bgs consists of olive gray to dark gray, yellowish brown silty sand with abundant shell
fragments ranging in size from fine sand to coarse sand.
B. Nature and Extent of Contamination
The SI conducted at the Site from 1993 to 1995 identified pesticides, PCBs, and metals in surface
soil and sediment.1 Specifically, the pesticides aldrin and dieldrin were detected at levels ranging
from non-detect to 0.0323 ppm (aldrin) and from non-detect to 0.586 ppm (dieldrin); the PCB
Aroclor 1260 was detected at levels ranging from non-detect to 18.7 ppm. The metals copper,
lead, mercury, nickel, and zinc were detected at levels exceeding background levels at
concentrations ranging up to 438 ppm (copper), 466 ppm (lead), 0.107 ppm (mercury), 200 ppm
(nickel), and 154 ppm (zinc). The herbicide MCPP was detected at levels ranging from 7.1 to
103 ppm. The SI report recommended further investigation, to include collection and analysis of
groundwater and subsurface soil samples and the evaluation of risk to human health and the
environment.
The abandoned substation was demolished and removed in the IRA conducted from April to June
of 1997.2 Soil was excavated 10 feet beyond the footprint of the foundation and to a depth of 2
feet, and was characterized and disposed of off site as nonhazardous waste. Confirmation soil
samples were collected at the limits of the excavation and at the base of the removed foundation.
None of the samples contained chemicals of concern (aldrin, dieldrin, and the PCB Aroclor
1260) above the approved preliminary remediation goals (PRO), and no further excavation was
required. In addition to demolition and removal of the foundation and adjacent soil, 147 feet of
storm sewer pipe at the Site were excavated and replaced. Confirmation soil samples were
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collected along the sidewalls and floor of the ditch to ensure that all soil associated with the
sewer line containing chemicals of concern above PRG was removed. All areas excavated
during the IRA were backfilled with clean material, graded to original contour, and seeded with
grass.
A focused RI was conducted from December 1997 through April 1998 to further investigate soil
at OU-47 and to determine grouhdwater quality.3 Surface (0 to 0.5 foot bgs) and subsurface (0.5
to 2 feet bgs and 2 to 4 feet bgs) soil samples were collected, and groundwater samples were
collected from four monitoring wells installed at the OU (Figure 3). An additional sediment
sample was collected from the storm sewer junction box west of the removed electrical
substation to verify the effectiveness of the IRA. Pesticides and metals were the only
constituents detected in soil during the RI (Figures 4 and 5). Dieldrin results ranged from 0.0065
to 0.11 ppm. Metals, including aluminum, arsenic, beryllium, iron, manganese, and vanadium,
were detected at levels ranging from 4,210 to 14,200 ppm (aluminum); 4.6 to 24.4 ppm (arsenic);
0.46 to 1.3 ppm (beryllium); 10,800 to 33,200 ppm (iron); 51.65 to 193 ppm (manganese); and
20.7 to 1770 ppm (vanadium). The focused RI proved the IRA was effective in reducing
contaminant levels to within EPA acceptable risk range.
VI. Current and Potential Future Site and Resource Uses
Current land use at OU-47 is classified as inactive industrial and future land use is expected to be
open space/recreational or commercial. There are currently no restrictions regarding use at OU-
47, such as fences and signs. Land adjacent to OU-47 is currently residential, open space, and
commercial. Future adjacent land use is expected to remain the same.
Groundwater in the shallow water table aquifer at Langley AFB is not currently used as a source
of drinking water at or within Vi mile of the Base.5 Groundwater near the coast is brackish to
saline, and therefore not potable.
VII. Summary of Site Risks
A risk assessment was conducted during the focused RI in accordance with the latest EPA policy
on risk assessments.6 The results are summarized below.
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A. Human Health Risk Assessment
The BLRA provides the basis for taking action and indicates the exposure pathways that need to
be addressed by the remedial action. It serves as the baseline indicating what risks could exist if
no action was taken at OU-47. This section of the ROD reports the results of the BLRA
conducted for this OU.
The risk assessment included estimates of the risk posed to human health and the environment
assuming an industrial current land-use scenario. The current land-use scenario estimates the
level of risk posed by Langley AFB's current use of the land. The current land-use scenario is
based on the assumption that the property remains under government control and continues in
current or like use. Although OU-47 is located near residences, given its size, location and
inactive status, it is unlikely that OU-47 will be used for residential purposes. However, the
human health risk assessment also evaluated residential receptors, in addition to the industrial
receptors, as a conservative estimate in the unlikely event that OU-47 might be developed for
residential use.
The human health risk assessment was based on exposure to soil. Groundwater was also
evaluated, but due to the establishment of a separate Basewide groundwater OU, groundwater
will not be addressed in this ROD. The ecological risk assessment evaluated risk based on
exposure to soil.
Health risks were based on a conservative estimate of the potential carcinogenic risk or the
potential to cause other health effects not related to cancer. Carcinogenic risks and
noncarcinogenic risks were evaluated. Three factors were considered:
• Nature and extent of contaminants at OU-47
• Pathways through which human and ecological receptors are or may be exposed to
those contaminants at OU-47
• Potential toxic effects of those contaminants.
Cancer risks are expressed as numbers reflecting the increased chance that a person will develop
cancer, if he/she is directly exposed (i.e., through working at the OU) to the contaminants found
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in the groundwater and soil at the OU over a period of time. For example, EPA's acceptable risk
range for Superfund sites is 1 x 10"* to 1 x 10"*, meaning there is one additional chance in ten
thousand (1 x 10"*) to one additional chance in one million (1 x 10"*) that a person will develop
cancer if exposed to a Superfund site. The risk associated with developing other health effects is
expressed as a hazard index (HI), which is the ratio of the existing level of exposure to
contaminants at a site to an acceptable level of exposure. Below an HI of 1, adverse effects are
not expected. An HI is also used to evaluate ecological risks.
Concentrations of chemicals detected in the soil during the focused RI were compared to risk-
based screening levels and background levels. The chemicals of potential concern (COPC)
identified in soil at OU-47 were metals and pesticides. The COPC were then evaluated in the
human health risk assessment.
Health risk levels, determined using EPA guidance to ensure that conservative estimates of
potential health effects are determined, differ depending on the assumed land use because human
exposure differs with land use. A conservative estimate of risk was developed incorporating the
potential exposure pathways including direct skin contact with contaminated soil, accidental
ingestion of soil, and inhalation of contaminated soil particles. Plausible receptors that may be
exposed to soil at the OU and which were evaluated in the risk assessment included a
groundskeeper, construction worker, child trespasser, and on-site resident.
The human health risk assessment concluded that the lifetime cancer risks to the receptors from
exposure to metals and pesticides in soil at OU-47 are 4.28 x 10"* for the groundskeeper, 3.79 x
10'9 for the construction worker, 7.09 x 10"8 for the trespassing child, and 1.51 x 10"6 for the on-
site resident. These lifetime risks are all within or below EPA's acceptable risk range of 1 x 10^
to 1 x 10"6. The HI for noncarcinogenic risk due to exposure to metals and pesticides in
contaminated soil is 0.07 for the groundskeeper, 0.03 for the construction worker, 0.2 for the
trespassing child, 0.5 for an on-site adult resident and 0.8 for the child resident. These values are
all below the acceptable level of 1.0, which indicates that adverse noncarcinogenic health effects
are unlikely to develop as a result of exposure through any of the exposure pathways. The
assumptions and results of the human health risk assessment are included in Tables 2 and 3.
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B. Ecological Risk Assessment
The ecological risk assessment at OU-47 was completed in two phases as agreed upon by the
Langley Partnership. The first phase was a screening exercise to determine whether chemicals at
the Site were sufficiently elevated enough to warrant further consideration as constituents of
potential environmental concern (COPEC). The second phase was conducted to evaluate
whether the identified COPEC were at sufficiently elevated concentrations to potentially pose a
risk to the ecology of OU-47.
Concentrations of 22 metals and 9 organochlorine pesticides, detected in surficial soil at OU-47,
were compared to EPA Region HI screening levels. The COPEC identified in soil at the Site
included 17 inorganic analytes (aluminum, antimony, beryllium, calcium, chromium, copper,
iron, lead, magnesium, mercury, nickel, potassium, selenium, silver, sodium, thallium, and
vanadium) and 2 pesticides (4,4'-DDE and dieldrin). The COPEC were then evaluated, using
food chain uptake models, to estimate ecological risk to soil invertebrates, mammals, and birds.
Receptors consisted of the earthworm, deer mouse, American robin, red fox, and red-tailed hawk.
The results of the exposure analysis were carefully evaluated. Nickel was shown to not pose risk.
The other 16 metals and 2 pesticides were shown to pose varying degrees of potential risk.
Additional considerations were included for various uncertainties (e.g., background
concentrations of inorganic analytes, essential nutrient status, and inorganic speciation) within
this assessment, as well as site size and habitat quality considerations, to determine whether or
not further site cleanup was required. Although the results indicate the potential for risk from
COPEC exists, the risk management decision of No Action was recommended based on these
uncertainties, as discussed in the RI Report.
C. Conclusions
The overall conclusion of the BLRA is that there is no adverse risk to human health and the
environment due to exposure to surface soil or total soil at OU-47. Cancer risks and noncancer
risks were estimated for plausible receptors directly or indirectly exposed to the media of interest.
The human health risk from exposure to surface soil and total soil calculated under current and
future land use scenarios are within EPA's acceptable risk range. Any adverse non-carcinogenic
health effects are unlikely to develop from the OU as a result of exposure through any of the
exposure pathways. Ecological risk assessment determined that there is minimal risk to
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terrestrial receptors at OU-47.
With the support of EPA and VDEQ, Langley AFB has selected No Action as the preferred
alternative for soil at OU-47; under this alternative, no remedial action would be undertaken
there. The selection of No Action is based on the conclusion, reached by the human health and
ecological risk assessments, that the soil at the Site poses no significant risk to potential human
or ecological receptors; therefore, No Action would be protective human health and the
environment.
Following review and considerations of the information in the Administrative Record, the
requirements of CERCLA and the NCP, and the public comments received on the Proposed
Plan, Langley AFB and EPA, in consultation with VDEQ, have selected the No Action-
alternative for OU-47.
VIII. Significant Changes from Proposed Plan
The proposed remedial alternative described in the Proposed Plan was No Action. No
significant changes to the proposed alternative were made.
IX. Responsiveness Summary
A. Overview
In a Proposed Plan released for public comment on September 13, 1998, Langley AFB, with the
support of EPA and VDEQ, identified No Action as the preferred remedial alternative for OU-
47.7 There were no written comments received as a result of the public comment period. There
were no written comments submitted during the September 24, 1998 availability session held in
Hampton, Virginia. There were three questions presented orally at the availability session
concerning OU-47. After evaluating.and addressing these comments, Langley AFB, with the
support of EPA and VDEQ, has selected No Action as the remedy for OU-47. Comments and
the associated responses of Langley AFB, EPA, and VDEQ are described below after a brief
discussion of community involvement to date.
B. Community Involvement to Date
The Langley AFB Partnership established a public comment period from September 13,1998 to
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October 12,1998 for interested parties to comment on the OU-47 Proposed Plan. These and all
other documents considered or relied upon during the remedy selection process for OU-47 are
included in the Administrative Record, which has been established in two information
repositories accessible to the public since the beginning of the public comment period for OU-47.
A public meeting was held at the Virginia Air and Space Center, Hampton, Virginia, on
September 24, 1998 to present the Proposed Plan, answer questions, and accept both oral and
written comments on the OU-47 remedial alternative. Two persons attended this session.
This Responsiveness Summary, required by CERCLA, provides a summary of citizens'
comments received during the public meeting and the responses of the Air Force, EPA, and
VDEQ. Responses to these comments are included in the section below.
C. Summary of Comments Received During Public Comment Period and
Comment Responses
Comment #1:
At the site where the electrical substation was removed, was soil removed, too? What material
was used to fill in the area, what other things were done, were trees planted?
Response #1:
In addition to removal of the structure, some soil was removed as well. All PCBs are gone but
some metals, such as vanadium, remain in very low concentrations. Clean soil was placed in the
area as fill after the structure and soil were removed, but no trees or shrubs have been planted at
the site.
Comment #2:
How much contamination was there at Site 51 (former Electrical Substation)?
Response # 2:
The site was relatively small, no bigger than the size of the room in which this meeting is being
held. The small size of the site contributed to the "No Action" proposal since the potentially
impacted receptors, such as the red-tailed hawk, would not select this area as a place to stay any
length of time. The concentration of contamination at the site is in the Proposed Plan, and are
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provided below:
Before the Interim Removal Action After the Interim Removal Action
PCBs:
copper: *
lead:
mercury:
nickel:
zinc:
MCCP (a herbicide):
Dieldrin:
aluminum:
arsenic:
beryllium:
iron:
manganese:
vanadium:
up to 18.7ppm
up to 438 ppm
up to 466 ppm
up to 0.107 ppm
up to 200 ppm
up to 154 ppm
up to 103ppm
non-detect
non-detect
non-detect
non-detect
non-detect
non-detect
non-detect
non-detect
non-detect
non-detect
non-detect
non-detect
non-detect
non-detect
up to 0.11 ppm
up to 14,200 ppm
up to 24.4 ppm
up to 1.3 ppm
up to 33,200 ppm
up to 193 ppm
up to 1,770 ppm
Comment #3:
What is each of your backgrounds and what kind of experience do you have to be in the positions mm
that you are in?
Response #3:
The EPA representative stated that she has been working with Federal CERCLA sites, including
other DOD installations, for 6 years.
The VDEQ representative stated that he had been working with Federal CERCLA sites,
including other DOD installations for 6 years.
The Langley representative stated that he had been working in the Air Force environmental
program for 12 years.
Each of the representatives stated that they had college degrees in disciplines related to their
current positions.
14
-------
X. References
lSite Inspection and Screening Risk Assessment Report for 33 Installation Restoration
Program Sites, Draft, Langley Air Force Base, Virginia, Radian Corporation, February 1996.
2Final Report of Field Activity, Installation Restoration Program Site OT-51, Langley Air
Force Base, Virginia, IT Corporation, October 1997.
3Final Focused Remedial Investigation Report for IRP Site OT-51, Langley Air Force Base,
Virginia, IT Corporation, September 1998.
4Langley Air Force Base Basewide Standard Operating Procedures: Background Information
Document, Versar, Inc., January 19,1996.
5Final Installation Restoration Program (IRP) Conceptual Hydrogeological Model Report for
Langley Air Force Base, Radian International, May 1998.
6Risk Assessment Guidance for Superfund, Volume I: Human Health Evaluation Manual
(Part A), Interim Final, U.S. Environmental Protection Agency, Office of Emergency and
Remedial Response, Washington, DC, EPA/540/1-89/002, 1989.
''Final Proposed Plan for Remedial Action at Installation Restoration Program Site OT-51,
Operable Unit 47, Langley Air Force Base, Virginia, Langley Air Force Base, September 1998.
15
-------
-------
APPENDIX A
Tables
-------
-------
Table 1
Summary of Operable Units Under CERCLA Investigation
Langley Air Force Base, Virginia
Page 1 of 3
OU Name/IRP Site Name
OU-21/LF-01
Former Landfill,-End of 08/26
Runway
Findings
Contaminants of Potential
Concern (COPCs) - pesticides
and metals in the groundwater
and soil.
Current Status
In the remedial investigation (Rl) phase. A
draft Rl report has been submitted and
reviewed. A separate basewide ecological risk
assessment is currently underway.
OU-22/WP-02
Former Waste Water Treatment
Plant, Bldg 724
COPCs - pesticides and metals
in the groundwater and soil.
In the Rl phase. A draft Rl report will be
submitted by mid-1999.
OU-23/LF-05
Former Landfill in the Shellbank
Area
COPCs • pesticides, volatile
organic compounds (VOCs),
and metals in the groundwater;
pesticides and metals in the
surface water and semivolatiie
organic compounds (SVOCs)
and metals in the soil.
In the Rl phase. A draft Rl report has been
submitted and reviewed. A separate basewide
ecological risk assessment is currently
underway.
OU-24/OT-06
Former Entomology Site,
Shellbank Area
COPCs - pesticides, VOCs,
SVOC, and some metals in the
groundwater; SVOCs, pesticides
and some metals in the soil.
In the Rl phase. A draft Rl report has been
submitted and reviewed. A separate basewide
ecological risk assessment is currently
underway.
OU-25/LF-07
Former Landfill, Shellbank Area
COPCs * pesticides and some
metals in the groundwater;
dieldrin in the soil.
in the Rl phase. A draft Rl report has been
submitted and reviewed. A separate basewide
ecological risk assessment is currently
underway.
OU-26/WP-08
Former Waste Water Treatment •
Plant, Lighter Than Air (LTA)
Area
COPCs - some pesticides and
metals in the groundwater;
dieldrin in the soil.
In the Rl phase. A draft Rl report has been
submitted and reviewed.
OU-28/LF-10
Former Landfill, Golf Course
COPCs - VOCs, metals and
some pesticides in the
groundwater; VOCs and
poiychlorinated biphenyls
(PCBs) in surface water, some
metals in the soil.
In the Rl phase. A draft Rl report has been
submitted and reviewed. A separate basewide
ecological risk assessment is currently
underway.
OU-29.LF-11
Former Landfill, Tabbs Creek
Area
COPCs - VOCs, pesticides.
metals and PCBs in the
groundwater; some metals in the
surface water; SVOCs, metals,
and PCBs in the soil.
In the Rl phase. A draft Rl report has been
submitted and reviewed. A separate basewide
ecological risk assessment is currently
underway.
OU-3Q/LF-12
Former Landfill, Munitions
Storage area, Northwest Area of
Base
COPCs - VOCs and metals in
the groundwater; metals and 2,4
OB in the surface water SVOCs
and nickel in the soil.
In the Rl phase. A draft Rl report has been
submitted and reviewed. A separate basewide
ecological risk assessment is currently
underway.
KNU339Mbll\12-9-98(4:7pm)
-------
Table 1
Summary of Operable Units Under CERCLA Investigation
Langley Air Force Base, Virginia
Page 2 of 3
OU Name/IRP Site Name
Findings
Current Status
OU-31/LF-13
Former Landfill Munitions Storage
Area, Nortnwest Area of Base
COPCs - Aldrin, alpha-BHC and
some metals in the groundwater,
VOCs. SVOCs, metals and
PCBs in the surface water.
In the Rl phase. A draft Rl report has been
submitted and reviewed. A separate basewide
ecological risk assessment is currently
underway.
OU-32/WP-14
Former Chemical Leach Pit,
Firing-ln Abutment, Building 1303
COPCs - pesticides, SVOCs,
and some metals in the
groundwater; arsenic and
dieldrin in the soil.
In the Rl phase. A draft Rl report has been
submitted and reviewed. A separate basewide
ecological risk assessmen: is currently
underway.
OU-33/LF-15
Former Landfill, Willoughby Point
COPCs - VOCs. SVOCs,
pesticides and metals in the
groundwater; pesticides and
metals in the surface water.
In the Rl phase. A draft Rl report has been
submitted and reviewed. A separate basewide
ecological risk assessment is currently
underway.
OU-34/LF-17
Former Landfill, LTA Area
COPCs - VOCs. pesticides and
some metals in the groundwater;
dieldrin and some metals
(mainly lead) in the soil.
In the Rl phase/ A draft Rl report will be
submitted by mid-1999.
OU-35/LF-18
Former Landfill, Northwest comer
of Base
COPCs * pesticides in the
groundwater; pesticides and
metals in the surface water;
SVOCs and manganese in the
surface soil; detta-BHC, and
metals in the sediment
In the Rl phase. A draft Rl report has been
submitted and reviewed. A separate basewide
ecological risk assessment is currently
underway.
OU-37/LF-22
Former Landfill. Willoughby Point
COPCs - pesticides and metals
in the groundwater; alpha-BHC,
detta-BHC and metals in the
surface water.
In the Rl phase. A draft Rl report has been
submitted and reviewed. A separate basewide
ecological risk assessment is currently
underway.
OlMQ/OT-25
Old Entomology Building and
Former Storage Area, BJdg 965
COPCs - pesticides in the
groundwater and soil.
In the Rl phase. A separate basewide
ecological risk assessment is currently
underway.
OU-42/OT-3BAandB
Four Waste Oil and Trash Bum
Areas, Basewide
Risk assessments showed no
significant risk to human health
or the environment from soils
In the Record of Decision (ROD) phase for
soils. Groundwater ROD will follow at a later
date. The final Rl report was submitted in
September 1998.
OU-44/FT-41
rormer Fire Training Area,
Firing-ln Abutment, Bldg 1303
COPCs - VOCs, pesticides,
dioxins, and some metals in the
groundwater SVOCs, dioxins
and some metals in the surface
water.
In the Rl phase. A draft Rl report has been
submitted and reviewed. A separate basewide
ecologicai risk assessment is currently
underway.
OU-47/OT-51
Former Electrical Substation,
hellbank Area. Bldg 82
COPCs - pesticides. PCBs and
lead in the soil.
In the ROD phase for soil. The Rl report and
proposed plan (PP) have been finalized. The
ROD is due to be finalized by the end of 1998.
XNV4339Mbmi2-9-98<4:7pn)>
-------
Table 1
Summary of Operable Units Under CERCLA Investigation
Langlay Air Force Base, Virginia
Pages of 3
OU NameflRP Site Nam*
OU-48/OT-55
Civil Engineering Yard,
Underground Petroleum
Contamination
OU-49/OT-56
Silver Contamination in Storm
Sewers, Basewkte
OU-50/SS-61
Old Civil Engineering Paint
Shop/Marina
OU-51/SS-63
Back River Sediments
OU-52/OT-64
Groundwater Contamination,
Basewide
Findings
COPCs - pesticides and dieldrin
in the groundwater; pesticides
and PCBs in the soil.
COPCs - metals and VOCs in
surface water and metals.
SVOCs and pesticides in
sediment.
COPCs • VOCs in the
groundwater and soil.
COPCs - pesticides, metals, and
PCTs in the sediment.
COPCs • pesticides and metals
in the groundwater.
Current Status
In the Rl phase. A draft Rl report is due to be
submitted by mid-1 999.
In the feasibility study (FS) phase. The FS is
due to be finalized by mid-1 999.
i
In the PP phase. The PP is due to be finalized
by the end of 1998.
In the preliminary assessment/site inspection
(PA/SI) phase. The draft PA/SI report is due to
be submitted by the end of 1998.
In the scoping phase. The long-term
monitoring project is due to be awarded by
mid-1999.
KNU339\tbll\12-9-98(4:7pnD
-------
Table 2
Variables Used to Estimate Potential Chemical Intakes
atid Contact Rates for Receptors at IRP Site OT-51 (OU-47)
Langley Air Force Base, Virginia
(Page 1 of 10)
Pathway
Variable
Groundskeeper
Construction
Worker
Child
Trespasser
On-Site
Resident
Inhalation ol VOC» and Rosucpmded Dutt from Soil
IR. (m'/hour)
Fl. (unllless)
ET. (hours/day)
EF (days/year)
ED (years)
BW(kg)
AT Noncancer (days)"
AT Cancer (days)*
2.5'
1"
1"
50°
RME:25§
CT:9C
70'
RME: 9,125
CT: 3,285
25.550
2.5*
1"
81
20"
1"
70«
365
25,550
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Inhalation of VOCs Irom Groundwater (Age Adjusted Resident - Cancer Evaluation)
lnhFrt (m3-year/kg-day)
Fl. (unitless)
ET, (hours/day)
EF (days/year)
AT Cancer (days)*
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
RME: 0.09"
CT: 0.02"
1"
RME: 0.33'
CT:0.17«
RME: 350'
CT: 234C
25,550
Inhalation of VOCa from Groundwater (Noncancer Evaluation)
KNW39/rel/2 WFDII2-9 91(16:7 pm)
-------
Table 2
Variables Used to Estimate Potential Chemical Intakes
and Contact Rates for Receptors at IRP Site OT-51 (OU-47)
Langley Air Force Base, Virginia
(Page 2 of 10)
Pathway
Variable
IR. (m%r)
Fl. (unitless)
ET. (hours)
EF (days/year)
ED (years)
BW (kg)
AT Non-Cancer (days)*
Groundskeeper
NA
NA
NA
NA
NA
NA
NA
Construction
Worker
NA
NA
NA
NA
NA
NA
NA
Child
Trespasser
NA :
NA
NA
NA
NA
NA
NA
On-Site
Resident
Adult: 0.83"
1"
Adult: 0.33'
RME: 350*
CT: 234°
Adult RME: 30*
Aduft CT^
Adult : 70*
Adult RME: 10,950
Adult CT: 3,285
Incidental Ingestion of COPC in Soil (Non-Residential)
IR. (mg/day)
Fl. (unitless)
EF (days/year)
ED (years)
BW (kg)
AT Noncancer (days)"
AT Cancer (days)*
501
0.125"
50"
RME: 25*
CT: 9C
701
RME: 9,125
CT: 3,285
25,550
480°
1b
20"
1b
70*
365
25,550
RME: 100*
CT:50"
0.625"
50"
RME: 12"
CT:^
43"
RME: 4,380
CT: 3,285
25,550
NA
NA
NA
NA
NA
NA
NA
KN/4339/TBL-2 WPDM2-9-98(l6:7 pm)
-------
Table 2
Variables Used to Estimate Potential Chemical Intakes
and Contact Rates for Receptors at IRP Site OT-51 (OU-47)
Langley Air Force Base, Virginia
(Page 3 of 10)
Pathway
Variable
Groundskeeper
Construction
Worker
" Child
Trespasser
On-Sfte
Resident
Incidental Ingestion of COPC In Soil (Age-Adjusted Residential Cancer Evaluation)
lngF.,,(mg-yrs/kg-day)
Fl, (unitless)
EF (days/year)
AT Cancer (days)'
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
RME: 114'
CT:ir
1»
RME: 350*
CT: 234e
25,550
Incidental Ingestion of COPC in Soil (Residential Non-Cancer Evaluation)
IR.(mg/d)
Fl, (unilless)
EF (days/year)
ED (years)
BW (kg)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Adult RME: 100*
Adult CT: SO"
Child RME: 200*
Child CT:100C
1"
RME: 350'
CT:234"
Adult RME: 30*
Adult CT: 9°
Child RME: 6'
Child CT: 1.8"
Adult : 70'
Child: IS1
KNHM9/TBL-2 WPDll2-9-9S
-------
Table 2
Variables Used to Estimate Potential Chemical Intakes
and Contact Rates for Receptors at IRP Site OT-51 (OU-47)
Langley Air Force Base, Virginia
(Page 4 of 10)
Pathway
Variable
AT Noncancer (days)d
Groundskeeper
MA
Construction
Worker
NA
Child
Trespasser
NA
On-Site
Resident
Adult RME: 10,950
Adult CT: 3,285
Child RME: 2,190
Child CT: 657
Ingestion of COPC in Drinking Water (Age Adjusted Resident - Cancer Evaluation)
IRF,M (L-year/kg-day)
Flw (unilless)
EF (days/year)
AT Cancer (days)'
MA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
RME: 1.09"
CT: 0.26"
1"
RME: 350"
CT: 234"
25,550
Ingestion of COPC in Drinking Water (Residential Noncancer)
IFUL-day)
Ft. (unitless)
EF (days/year)
ED (years)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Adult RME: V
Adult CT: 1.4"
Child RME: 1"
Child CTM11
1"
RME: 350'
CT:234C
Adult RME: 30'
Adult CT: 9°
Child RME: 6'
Child CT: 1.8"
KN/«39/rBU2.WPD\l 2-9-98(16:7 pm)
-------
Table 2
Variables Userfl to estimate Potential Chemical Intakes
and Contact Rates for Receptors at IRP Site OT-51 (OU-47)
Langley Air Force Base, Virginia
(Page 5 ol10)
Pathway
Variable
BW
-------
Table 2
Variables Used to Estimate Potential Chemical Intakes
and Contact Rates for Receptors at IRP Site OT-51 (OU-47)
Langley Air Force Base, Virginia
(Page 6 of 10)
Pathway
Variable
BW(kg)
AT Noncancer (days)4
AT Cancer (days)' •
AF (mg/cm!)
ABS (unitless)
Groundskeeper
70'
RME: 9.125
CT: 3,285
25,550
0.2"
csv
Construction
Worker
701
365
25.550
0.2"
CSV
Child
Trespasser
43"
RME: 4,380
CT: 3,285
25,550
0.2"
CSV
On-Site
Resident
NA
NA
NA
NA
NA
Dermal Uptake of COPC from Soil (Age Adjusted Resident - Cancer Evaluation) (Eq.,,)
SFS.,1 (cm2-year/kg-day)
Fla (unitless)
EF (days/year)
AT Cancer (days)*
AF (mg/cm*)
ABS (unilless)
MA
MA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
RME: 2700"
CT.BOCf
1"
RME: 350'
CT:234C
25,550
0.2"
CSV
Dermal Uptake ol COPC from Soil (Residential Noncancer)
SA (cm2)
Fld (unitless)
EF (days/year)
NA
NA
NA
NA
NA
NA
NA
NA
NA
Adult : 5000°
Child: 2400"
1"
RME: 350*
CT: 234'
KN/4339/TBl^2WPD\l 2-9-98(16 7pm)
-------
table 2
VaTJlblea UsetJ to Estimate Potential Chemical Intakes
and Contact Rates for Receptors at IRP Site OT-51 (OU-47)
Langley Air Force Base, Virginia
(Page 7 of 10)
Pathway
Variable
ED (years)
BW(kg)
AT Noncancer (days)"
AF (mg/cm!)
ABS (unllless)
Groundskeeper
NA
NA
NA
NA
CSV
Construction
Worker
NA
NA
NA
NA
CSV
Child
Trespasser
NA
NA
NA
NA
CSV
On-Site
Resident
Adull RME: 30'
Adult CT: 9"
Child RME: 61
Child CT: 1.6"
Adult : 70'
Child: 15'
Adult RME: 10,950
Adult CT: 3.285
Child RME: 2, 190
Child CT: 657
0.2"
CSV
Dermal Uptake of COPC from Qroundwater (Aga Adjusted Resident • Cancer Evaluation) (Eq.,,)
SFW.,, (cm'-year/kg-day)
Fld (unllless)
EF (days/year)
AT Cancer (days)'
PC (cm/hour)
lau (hours)
ET,, (hours/day)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
RME: 10,000"
CT: 2,900"
1"
RME: 350'
CT: 234'
25,550
CSV
CSV
RME:0.33'
CT:0.17"
KN/«Wnil,3 WPDM2 9 98(16:7 pm)
-------
Table 2
Variables Used to Estimate Potential Chemical Intakes
and Contact Rates for Receptors at IRP Site OT-51 (OU-47)
Langley Air Force Base, Virginia
(Page 8 of 10)
Pathway
Variable
Groundskeeper
Construction
Worker
Child
Trespasser
On-Sile
Resident
Dermal Uptake of COPC from Groundwater (Rasidential Noncancer Evaluation)
SA(crrr*)
Fla (unitless)
EF (days/year)
ED (years)
BW(kg)
AT Noncancer (days)"
tau (hours)
PC (cm/hour)
ETd (hours/day)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Adult : 20,000s
Child: 7,300"
1"
RME: 350*
CT:234e
Adult RME: 30*
Adult CT: &
Child RME: 6>
Child CT: 1.8"
Adult: 70*
Child: IS'
Adult RME: 10.950
Adult CT: 3,285
Child RME: 2,190
Child CT: 657
CSV
NA
RME0.33'
CT: 0.17"
Dermal Uptake of COPC from Groundwater (Non Residential)
SA (cm1)
Ft* (unitless)
4100°
1"
4100"
1"
NA
NA
NA
NA
KN/43W/TBL-2 WPD\l2-9-9S
-------
Table 2
Variables Used to Estimate Potential Chemical Intakes
and Contact Rates for Receptors at IRP Site OT-51 (OU-47)
Langlay Air Force Base, Virginia
(Page 9 of 10)
Pathway
Variable
EF (days/year)
ED (years)
BW(kfl)
AT Noncancer (days)"
AT Cancer (days)'
PC (cm/hour)
lau (hours)
EL (hours/day)
Groundskeeper
SO"
RME: 25*
CT: 9'
70'
RME: 9, 125
CT: 3,285
25,550
csv
CSV
1"
Construction
Worker
20"
1'
70*
365
25550
CSV
csv
1"
"" Child
Trespasser
NA
NA
NA
NA
NA
NA
NA
NA
On-Slte
Resident
NA
NA
NA
NA
NA
NA
NA
NA
ABS = Absorption factor.
csv = Chemical-Specific Value.
EF = Exposure frequency.
lngFM = Age-adjusted ingeslion factor.
IR, = Ingestion rate.
RME = Reasonable Maximum Exposure.
SFSM > Age-adjusted soil skin contact factor.
VOC = Volatile organic compound.
AT = Averaging time.
CT = Central tendency.
ET = Exposure time.
InhF = Age-adjuslerf inhalation factor,
NA = Not Applicable.
SA a Surface area of the skin available for contact with site medium.
SFW.O, =• Age-adjusted water skin contact factor.
BW = Body weight.
ED = Exposure duration.
Ft = Fraction of exposure attributed to site medium.
IR, - Inhalation rale.
PC = Pormeabilily coeflicient.
•U.S. Environmental Protection Agency (EPA), 1991, Risk Assessment Guidance for Superiund Volume I: Human Health Evaluation Manual Supplemental
Guidance, Standard Default Exposure Factors, Interim Final, Office of Solid Waste and Emergency Response, OSWER Directive: 9285.6-03.
"Assumed; see Final Focused Remedial Investigation Report tor IRP Site OT-51, Langlay Air Force Base, Virginia, (IT. 1998).
-------
Table 2
Variables Used to Estimate Potential Chemical Intakes
and Contact Rates for Receptors at IRP Site OT-51 (OU-47)
Langley Air Force Base, Virginia
(Page 10 of 10)
CU.S. Environmental Protection Agency (EPA), 1993, Superfund's Standard Default Exposure Factors for the Central Tendency and Reasonable Maximum
Exposure, Preliminary Review Draft (5/5/93).
"Calculated as the product of ED (years) x 365 days/year.
•Calculated as the product of 70 years (assumed human lifetime) (EPA, 1989, Risk Assessment Guidance for Superfund, Volume 1, Human Health
Evaluation Manual [Part A], Interim Final, Office of Emergency and Remedial Response, Washington, DC, EPA/540/1-8/002,1989) x 365 days/year).
'U.S. Environmental Protection Agency (EPA), 1995a, Letter from W. Arguto, EPA Region III, to W. E. Budrus, U.S. Army Engineer District, Huntington,
dated October 18.
"U.S. Environmental Protection Agency (EPA), 1992, Dermal Exposure Assessment: Principles and Applications, Interim Report, Office of Research and
Development, Washington, DC, EPA/600/8-91/011B, including Supplemental Guidance dated August 18,1992.
"U.S. Environmental Protection Agency (EPA), 1996, Exposure Factors Handbook, Volume I of III - General Factors, Office of Health and Environmental
Assessment, Washington, DC, EPA/600/P-95/002 Ba. 89/043.
'U.S. Environmental Protection Agency (EPA), 1997, Risk-Based Concentration Table, 22 October, EPA Region III, Philadelphia, PA, on-line.
-------
Table 3
Summary of Site-Related RME Cancer Risk and Noncancer Hazard for IRP Site OT-51 (OIM7)
Langley Air Force Base, Virginia '
Receptors
*—^••M^MHM^H^B.M
Groundskeeper
Construction Worker
Child Trespasser
Age-Adjusted Resident
Surface
Soil
Site-Related
. ILCR
1.01E-08
w NA
7.09E-08
kient MA
Surface
Soil
Site-Related
HI
1.12E-02
ar NA
1.56E-01
lent NA
tent NA
Total
Soil
Site-Related
ILCR
NA
3.79E-09
NA
1.51E-06
Total
Soil
Site-Related
HI
NA
3.50E-02
NA
5.04E-01
1.79E+00
— —
Groundwater
Site-Related
ILCR
8.24E-05
1.32E-06
NA
1.78E-03
Groundwater
Site-Related
HI
6.55E-01
2.62E-01
NA
9.11E+00
2.11E+01
Total
ILCR
All
Pathways
^^^^^^"^^^^^^*^^*"«*"^»»W«B»M
8.24E-05
1.32E-06
7.09E-08
1 7flP.fW
l.l OC'IIO
Total
HI
All
Pathways
6.66E-01
2.97E-01
1.56E-01
9.61 E+00
2.29E+01
Receptors
Groundskeeper
Construction Worker
Child Trespasser
On-Site Adult Resident
On-Site Child Resident
^^•••••••^^^•^••"••••••••••••M
HI = Hazard index
ILCR = Incremental lifetime cancer risk
NA= Not Applicable
RME = Reasonable Maximum Exposure
KNV433:
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APPENDIX B
Figures
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OHALL
Ci M T\OS\CI vlL\7743B=iEB. B3B
NOV qB|ORABN BT. D. BllLINCSLET DRAWN BY' DH«LL ENCR. CHCK. BY*. Thorbjornscn PROJ. UGR.: 0. BOWHOL
IS! 16; BS [SIARTING DATE: 6/3/96 DATE LAST RElgS NOV 18 DRAFT. CHCK. B^ C. TUMLIH INIIIATOR-K Thorbjornse OWC. NOj\77«B
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IF-J2
tAKGUT KP SITE BOUNOAflY
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FIGURE 2
2000
4000rEET
BASE MAP OF LANGLEY AFB
SHOWING THE LOCATION OF IRP
SITE OT-5HOU-47)
| INTERNATIONAL
ItCHNOLOGY
COMI'ORATtON
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FORMER ELECTRICAL
SUBSTATION (KMOLISHEO
MO REMOVED.
HAY-JUNE IM7I
UEGEMJ-
5VPOI Q SURFACE/SueSURf ACE
0*ECT- PUSH SOt SAMPlf (19971
5ISDOI a SEWER SEQUENT SAMPIE (IS97I
SHALLOW HOMIORNC WELL (19971
SOI. BORtNC (19971
5ISB01
."~l CXCAVATION AREA (MTERM REMOVAL
i^L' *CTWN. MAr-JLNt 19971
SCA1E
40
BO FEET
FIGURF 3
IRP "SITE OT-51
FOCUSED Rl
SAMPLING LOCATIONS
UNITED STATFS AIR FORCE
LANGLCf AIR FORCE BASE
HAUPTOH. VIRGINIA
\ INTERNATIONAL
TECHNOLOGY
' CORPORATION
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LEGEtiQ:
5ISB02U SfX BOftHC LOCATION
5K00/ f-l <:fn SAUPLE LOCATION
SEOiUtHT SAUPLE LOCATION
WAUTE DETECTED H TI«E ASSOCIATED BLANK
BCIOW CAOUMI SURFACE
FCLO DUPLICATE
ESTWATED VAIUF GREATER THAN
LMI AND LESS THAN
FORMER ELECTRICAL
SUBSTATION IDEMOLISHEO
AND REMOVED,
MAY-JUNE W47I
.» *\
ULLKRAMS PER KLOCRAM
NOT DETECTED
^CONCENTRATION (EPA REGION «.
"9'"'9 >r^ROCRAUS PER KIOCRAM
'7' EXCAVATION AHFA (INTERIM REUOVAI
I :J ACTION. MAY-JUNE 1997)
FIGURE 4
IRP SITE OT-51
SURFACE SOIL ANALYTICAL
RESULTS ABOVE SCREENING
LEVELS (DECEMBER 1997)
UNITED STAT£S AIR FORU
I ANCLEY AM ftWCr BASE
HAMPTON. VIRGINIA
INTERNATIONAL
IECHNOLOGY
CORPORATION
-------
5ISR02 a SOt BOR*C LOCATION
S0». SAMPLE LOCATION
SISDOIH SEDIMENT SAMPLE LOCATION
B WM1.VTC DETECTED
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APPENDIX C
Glossary
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-------
Administrative Record: A collection of documents containing all the information and reports generated
during the entire phase of investigation and cleanup at the site and used to mate a decision on the selection
of the preferred alternative under CERCLA.
Carcinogenic Risk: Cancer risks are expressed as numbers reflecting the increased chance that a person
will develop cancer if exposed to chemicals or substances. For example, EPA's acceptable risk range for
Superfund sites is 1 x 10"* to 1 x 10*6. This means that the probability of cancer should not be greater than
1 in 10,000 chance to a 1 in 1,000,000 chance above background.
Comprehensive Environmental Response, Compensation and Liability Act (CERCLA): A federal
law, commonly referred to as the Superfund Program, passed in 1980 that provides for the cleanup and
emergency response in connection with numerous existing inactive hazardous waste disposal sites that
endanger public health and safety of the environment.
Chemicals of Potential. Concern (COPC): Chemicals, either present at the site as a result of historical
activities or of likely concern to human health and the environment, which are evaluated in the risk
assessment
«
Ecological Risk Assessment: An evaluation of the risk posed to the environment if remedial activities are
not performed at the site.
Exposure Pathways: Describes the course a chemical or physical agent takes from the source to the
exposed individual. Elements of the exposure pathway are: (1) the source of the released chemical; (2) the
contaminated medium (e.g., soil); (3) a point of contact with the contaminated medium; and (4) an
exposure route (e.g., ingestion, inhalation) at a contact point
Hazard Index (HI): A number indicative of noncarcinogenic health effects which is the ratio of the
existing level of exposure to an acceptable level of exposure. A value equal to or less than one indicates
that the human population is not likely to experience adverse effects.
Human Health Risk Assessment: An evaluation of the risk posed to human health should remedial
activities not be implemented.
Installation Restoration Program (IRP): Program established by the United States Air Force to
systematically identify and remediate contaminated sites. The IRP was designed to be consistent with EPA
rules and guidelines.
Operable Unit (OU): A discrete portion of a site or a discrete action representing an incremental step in
the investigation and remediation of hazardous substances at a facility.
Proposed Plan: A document that presents a proposed cleanup alternative and requests public input
regarding the proposed alternative.
Record of Decision (ROD): A legal document that describes the cleanup action or remedy selected for a
site, the basis for the choice of that remedy, and public comment on alternative remedies.
Remedial Action: Implementation of plans and specifications, developed as part of the design, to
remediate a site.
Remedial Investigation (RI): Part of a study of a facility that supports the selection of a remedy for a site
-------
where hazardous substances have been disposed. The RI identifies the nature and extent of contamination
at the facility.
Site: The facility and any other areas in close proximity to the facility where a hazardous substance,
hazardous waste, hazardous constituent, pollutant, or contaminant from the facility has been deposited,
stored, disposed of. or placed or has migrated or otherwise come to be located.
Site Inspection (SI): The SI determines if the site presents an immediate threat that requires prompt
response action because the site may pose a threat to human health and/or the environment.
Site-Related Risk: Cancer and non-cancer risk estimates that are based on contaminants present in
environmental media due to site-specific human activities at Langley AFB, but that exclude the con-
tribution of background contaminant concentrations.
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