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PUBLIC HEALTH ASSESSMENT

U.S. DEFENSE GENERAL SUPPLY CENTER
RICHMOND, CHESTERFIELD COUNTY, VIRGINIA


ENVIRONMENTAL CONTAMINATION & OTHER HAZARDS

The contaminants discussed in subsequent sections of this publichealth assessment will be evaluated to determine whether exposureto them has public health significance. ATSDR selects anddiscusses contaminants based on their environmentalconcentrations with consideration for 1) field and laboratorydata quality, 2) sample design and adequacy, and 3) comparison ofon- and off-site concentrations. Environmental concentrationsare evaluated using comparison values for non-carcinogenic andcarcinogenic endpoints and community health concerns. Thepotential for adverse health effects from those contaminants ofconcern will be discussed in the Public Health Implicationssection of this document.

Comparison values for ATSDR public health assessments arecontaminant concentrations in specific media (air, water, soil,etc.) used to select contaminants of concern for furtherevaluation. The values are developed by environmental and healthagencies to provide an estimate of concentrations present in eachenvironmental medium that should be evaluated for possible healtheffects if exposures to the contaminants occur. An explanationof comparison values and quantitative units used in this documentare described in Appendix B.

The contaminants of concern at each site for which environmentaldata were available for review are listed in the site tables inAppendix A. The comparison value that is listed in a table wasselected because a contaminant concentration exceeded that valuein a particular environmental medium. In Table 5, for example,1,1,1-trichloroethane is listed because it was detected in bothgroundwater and soil samples. Only the comparison value forgroundwater concentrations was exceeded; therefore, thegroundwater comparison value is used. The other mediaconcentrations are included to identify those that may becontinued sources of groundwater contamination at the site and toidentify data that are lacking but would be useful incharacterizing the site.

Likewise, a contaminant may have exceeded comparison values inmore than one medium (e.g., groundwater and soil). Only onecomparison value is provided in the table, but other media areconsidered when evaluating the public health implications.

Comparison values for a contaminant differ for each environmentalmedium. Therefore, comparison values used for a contaminantlisted in one table may be different than those used in anothertable, particularly if the environmental medium is not the same.

An overview of the contamination of groundwater, soils, surfacewater, and other environmental media is presented to show howindividual sites (source areas) may be affecting the installationas a whole and the surrounding communities. An overview ispresented in the following paragraphs, followed by site-specific(source areas) information.

A. On-Post Contamination

Groundwater

Groundwater contamination has been identified at five DGSC sites. Data for groundwater at other sites are not yet available. Theshallow aquifer is contaminated at three of the five sites; thedeep aquifer is contaminated at four sites. The primarycontaminants are volatile organic chemicals (VOCs). Groundwaterflow patterns and contaminant migration potential are discussedin the Pathways Analyses section of this document. The summarytable that follows shows which sites are impacting each aquifer.



Summary of Groundwater Contamination
Site Shallow Aquifer
Contamination
Deep Aquifer
Contamination



Open Storage Area
X
X
Area 50There is no shallowaquifer in this area.1
X
National GuardArea
X
X
Fire Training Area
X
X
AcidNeutralizationPits
X
The deeper aquiferhas not beensampled.1
1 Reference: Dames and Moore 1989b.

Contaminants of concern and their concentrations are listed inTables 2-8 in Appendix A and are discussed in the site-specificsections.

Groundwater data were recently collected and analyzed for twoadditional sites, Building 112 and the Fuel Oil Storage Area (LawEnvironmental, Inc. 1993). Those results are discussed in thesite-specific sections.

Soils

Soil samples from five sites have been collected and analyzed. Contaminants of concern have been detected only at the FireTraining Area. Both surface and subsurface soils at the sitecontain contaminants of concern, including heavy metals.

Soil samples from four additional sites have recently beencollected and analyzed for Buildings 112, 202, 68 and the FuelOil Storage Area (Law Environmental, Inc. 1993). Those resultsare discussed in the site-specific sections.

Surface Water and Sediments

Surface water and sediment samples have been collected andanalyzed for two streams at DGSC. Flow patterns and theindividual sites that affect each stream are discussed in thePathways Analyses section. Surface water and sediments arecontaminated in the No-Name Creek that originates on theinstallation and in Kingsland Creek. Metals, VOCs, and PAHs werefound in surface water; petroleum hydrocarbons were detected insediments. Kingsland Creek is discussed in the Off-SiteContamination section.

Both creeks were recently sampled in October of 1992. Thoseresults are discussed in subsequent site-specific sections (LawEnvironmental, Inc. 1993).

Air

No air monitoring has been performed at any of the sites. However, soil gas surveys were performed during the remedialinvestigations of the Open Storage Area/Area 50/National GuardArea and the Fire Training Area. VOCs were detected in soil gasassays at the National Guard Area and the Fire Training Area. Findings are further described in the Pathways Analyses section.

Biota

No edible animals or plants have been tested for contamination. The aquatic animals that were subjected to tests using water fromcreek systems at the installation (see site-specific discussions)were used as water quality indicators and not for contaminantuptake potential.

Site-Specific Contamination

The site-specific contamination which was detected in eachenvironmental media is organized for each source area. Tables 2-8 in Appendix A list contaminants detected in the source areas atlevels greater than comparison values.

Open Storage Area

Groundwater
Monitoring well data for the Open Storage Area werecollected quarterly from 1985-1987. Total depths of thewells ranged from 16 - 122 feet at the Open Storage Area. Twelve wells were placed in the upper aquifer, seven wellsin the lower aquifer, and three wells in the bedrock.

The ranges of concentrations for contaminants of concern inthe Open Storage Area are presented in Table 2. Volatileorganic compounds are contaminants of concern. In somewells, the water was tested for a limited number ofinorganic chemicals. Lead was analyzed for in only twowells (Dames and Moore 1989b). No lead was detected inwater from either well above the detection limit of 5 partsper billion (ppb).

Soils
Soil samples from the Open Storage Area were collected andanalyzed in 1985, 1986, and 1988. Samples from 49 soilborings were analyzed. Boring depths ranged from 10 - 110feet. Samples for analysis were taken from boring depthsranging from 1 - 56 feet. Organics, inorganics, and semi-volatile organics were sampled for in the soils (Dames andMoore 1989b). No contaminants of concern were detected inthose samples.

Area 50

Groundwater
Monitoring well data for Area 50 were collected quarterly from 1985-1987. The ranges of concentrations for contaminants of concern in Area 50 are presented in Table 3. The wells ranged from total depths of 19.5 - 117 feet. Twelve wells were in the upper aquifer, two wells were in the lower aquifer, and one well was in the bedrock. Limited inorganic chemical analyses were performed; not all wells were sampled for metals. In five wells, the water was analyzed for lead (Dames and Moore 1989b). Lead was not detected.
Soils
Soil samples from Area 50 were collected and analyzed in1984, 1985, 1986, and 1988. Samples were analyzed from 61soil borings; boring depths ranged from 16 - 117 feet. Samples for analysis were taken from boring depths rangingfrom one - 30 feet. Samples were analyzed for organics,inorganics, and semi-volatile organics (Dames and Moore1989b). No contaminants of concern were detected in thosesamples.

National Guard Area

Groundwater
Monitoring wells have been placed in the National GuardArea, and U.S. Geological Survey (USGS) well clusters arenear the National Guard Area. Monitoring well data werecollected quarterly from the National Guard Area wells from1985-1987. The ranges of concentrations for contaminants ofconcern in the National Guard Area are presented in Table 4. The wells ranged from total depths of 15.5 - 66 feet. Twenty-three wells were in the upper aquifer, and 23 wellswere in the lower aquifer (Dames and Moore 1989b).

USGS also installed 68 monitoring wells on installationproperty outside the National Guard Area to the north andeast. The wells are arranged in 10 clusters; each clustercontains four to five wells. At least one well in eachcluster is in the upper aquifer and at least three wells arein the lower aquifer at varying depths. The deepest well inthe lower aquifer is 72 feet below the ground surface (Damesand Moore 1989b).

Concentration ranges for contaminants of concern in theNational Guard Area are shown in Table 4. Analyses for leadand other pertinent metals associated with the types ofwastes generated at the facility were not conducted. Someupgradient wells were tested, and the water was analyzed forsome metals, including lead (CH2M Hill 1991). The maximumlevel of lead detected in those upgradient wells was 13 ppb.

Soils
Soil samples from the National Guard Area were collected and analyzed in 1984 and 1985. Samples were analyzed from 130 soil borings: 58 borings in the National Guard Area, 64 borings downgradient (east) of the area, and eight borings upgradient (west) of the area. Boring depths ranged from 10.5 - 122 feet. Samples for analysis were taken from boring depths ranging from one - 54 feet. Samples were analyzed for organics, inorganics, and semi-volatile organics (Dames and Moore 1989b). No contaminants of concern were detected in those samples.
Sediment
In 1988, sediment samples were collected from the No-NameCreek north of the National Guard Area and analyzed fororganics, inorganics, and semi-volatile organics. Onlypetroleum hydrocarbons were detected in samples. Theconcentrations ranged from 31,000 - 430,000 ppb. Componentsof petroleum hydrocarbons were not provided in the datareviewed (Dames and Moore 1989b).

In October of 1992, sediment samples were collected both onand off site from the No-Name Creek and analyzed for VOCs,base neutral/acid extractable semi-volatiles (B/N/As),pesticides/PCBs, total metals, Total Organic Carbon (TOC),cyanide, hexavalent chromium, and grain size analysis (LawEnvironmental, Inc. 1993). Although some volatiles, semi-volatiles, pesticides, total metals, and TOC wereoccasionally detected, adverse health effects are notlikely.

Surface Water
From 1981 to 1988, surface water samples were collected foranalyses from No-Name Creek and drainage areas near theNational Guard Area. The creek is on installation propertyand flows off the property into the adjacent neighborhood. Samples were collected from both on and off the installationproperty boundaries. Samples were analyzed for organics,inorganics, and semi-volatile organics (Dames and Moore1989b). Ranges of concentrations of contaminants of concernare presented in Table 4. The highest concentrations werefound on DGSC in the No-Name Creek (Dames and Moore 1989b)which originates in an industrial area and flows off theinstallation. Off-site, where people are more likely to beexposed, concentrations were below detection limits, anddetection limits are below comparison values for thismedium.

Ambient aquatic 7-day chronic toxicity tests were conductedusing surface water samples from the No-Name Creek. Ceriodaphnia dubia (water fleas) and Pimephales promelas(fathead minnows) were used in the tests. A benthicmacroinvertebrate study also was conducted on samples fromthe creek. Results of the studies indicate the creek hasbeen moderately affected, possibly by the contaminantspresent in the stream. A definition of "moderatelyaffected" was not provided in the report (Dames and Moore1989b).

In October of 1992, surface water samples were collectedboth on and off site from the No-Name Creek and analyzed forvolatile organics (VOCs), B/N/As, pesticides/PCBs, totalmetals, cyanide, hexavalent chromium, total dissolved solids(TDS), conductance and pH (Law Environmental, Inc. 1993). Although some volatiles and total metals were occasionallydetected, adverse health effects are not likely.

Soil Gas
Soil gases from the National Guard Area were analyzed inOctober 1988. No individual VOCs were identified at aconcentration greater than the detection limit. However,total VOCs were recorded as ranging from <1 - 84 ppb (Damesand Moore 1989b).

Fire Training Area

Groundwater
Groundwater samples were collected and analyzed in 1982, 1985, 1987, and 1988 to help define the lateral and vertical migration of contaminants from the site. Total well depths of the 18 monitoring wells ranged from 15 - 70 feet. The wells include two on the southern side of Kingsland Creek across from the installation. Those two wells are 15 and 40.5 feet deep. Contamination was detected in the two off-site monitoring wells as well as the monitoring wells on site (Dames and Moore 1989c). The contaminants of concern detected in groundwater at the site are presented in Table 5.
Soil
In 1985 and 1986, surface soil samples from the Fire Training Area were collected for analysis. The surface samples were collected from surface soil composites from 1 -1.5 feet deep. Subsurface soil samples (>1 foot) were analyzed in 1985, 1986, and 1988 (Dames and Moore 1989c). The ranges of concentrations of contaminants of concern are presented in Table 5.
Soil Gas
Between October and November of 1986, soil gas data werecollected. The soil gas data were used to map thesubsurface presence of organic solvents in order to definecontaminant plumes and determine the best locations formonitoring well installation (Dames and Moore 1989c). Soilgas data are presented in Table 5.

Acid Neutralization Pits

Groundwater
In 1987 and 1988, groundwater samples were collected at the Acid Neutralization Pits for analysis. Four wells and two piezometers were installed at the site; total depths of the wells and piezometers ranged from 18 - 26 feet. All wells were in the upper aquifer (Dames and Moore 1989a). The contaminants of concern detected in groundwater are shown in Table 6.
Soils
In 1986 and 1987, soil samples were collected and analyzed. Samples were collected from eight soil borings; the boringdepths ranged from 10 - 26 feet (Dames and Moore 1989a). Nocontaminants of concern were found in the soils.

Aluminum Phosphide Residue Disposal Area

Groundwater
One upgradient and two downgradient monitoring wells were tested to determine if aluminum and phosphorous exceeded background levels. The upgradient well was used to establish the background levels. Aluminum was measured in the groundwater at 1,000 ppb, and phosphorous was measured at 500 ppb. Aluminum was detected at a maximum concentration of 1,830 ppb which is slightly above background levels. Phosphorous was not detected above background levels. Comparison values for elemental aluminum and phosphorous in drinking water have not been established. Therefore, background values are being used as comparison values. Aluminum phosphide is used as a pesticide, and once the pellets have reacted, there is no reactive ingredient left. Therefore, aluminum phosphide is not expected to be present at the area because the material disposed of in this area was residue from reacted pellets of aluminum phosphide (Environmental Restoration Company 1991).
Soils
Subsurface soil samples taken from borings indicated that aluminum and phosphorous are present in soils at theAluminum Phosphide Residue Disposal Area. Concentrations ofaluminum ranged from 117,000 ppb to 1,778,000 ppb. Concentrations of phosphorous ranged from 900 ppb to 135,000ppb. Background levels for aluminum are 600,000 ppb foraluminum and 200 ppb for phosphorous (EnvironmentalRestoration Company 1991). Health-based comparison valueshave not been established for elemental aluminum andphosphorous in this medium. No aluminum phosphide isexpected to be present.

Parker Pond

Foodchain
Following a fish kill in 1987, one fish sample was sent to a laboratory for analysis. The dead fish, stocked from another source not associated with the installation, contained 260 ppb of DDT. In 1988, one surface water sample and two sediment samples were collected and analyzed for DDT. No DDT was measured; the detection levels were set at 3.4 ppb for the water and at 3,400 ppb for the sediment samples (DGSC 1991b).
Surface Water and Sediment
In 1991, Atlantic Environmental Laboratory, Inc. conducted amore extensive investigation of the pond. Seven watersamples and ten sediment samples were collected and analyzedfor DDT [p,p'-dichlorodiphenyltrichloroethane], DDD [p,p'-dichlorodiphenyldichloroethane], DDE[p,p'dichlorodiphenyldichloroethene], 2,4-D [2,4-dichlorophenoxy acetic acid], 2,4,5-T [2,4,5-trichlorophenoxyacetic acid], and 2,4,5-TP [2(2,4,5-trichlorophenoxy)propionic acid]. A detection limit of 1ppb was used for the water samples, and 1,000 ppb was thedetection limit used for the sediment samples. Nopesticides were measured above detection levels (DGSC1991b).

Building 112--Pesticide Generalization and Recycling Building

Groundwater
During early 1993, groundwater samples were collected (Law Environmental, Inc. 1993 ). Groundwater samples were analyzed for volatile organics (VOCs), B/N/As, pesticides/PCBs, total and dissolved metals, and pH. Total lead, total beryllium, and total chromium were detected above environmental comparison values in monitoring wells for Building 112 (Table 7).
Soil
During early 1993, surficial soil samples were collected(Law Environmental, Inc. 1993). Surface soil samples were analyzed for VOCs, B/N/As, pesticides/PCBs, and totalmetals. The samples for VOCs were collected at the intervalof 1-2 feet and samples for the remaining parameters werecollected at the interval of 0-2 feet. Benzo (a)anthracene, Chrysene, 4,4'-DDT, and total arsenic were theonly compounds detected at concentrations aboveenvironmental comparison values (Law Environmental, Inc.1993). Only limited numbers of remedial workers,contractors, and possibly installation personnel would haveaccess to the area. Further information is included in thepathways analyses section.

Building 68--Suspected PCB Spill Site

Soil
During early 1993, surficial soil samples were collected toquantify the level of pesticide and PCB contaminationpresent (Law Environmental, Inc. 1992b, Law Environmental,Inc. 1993). Surface soil samples were analyzed for VOCs,B/N/As, pesticides/PCBs, and total metals. The samples forVOCs were collected at the interval of 1-2 feet and samplesfor the remaining parameters were collected at the intervalof 0-2 feet. Some PAHs (Benzo [a] anthracene, Benzo [a]pyrene, Benzo [b] fluoranthene, Benzo [f] fluoranthene,Chrysene, Indeno [1,2,3-cd] pyrene) and total arsenic werethe only compounds detected above environmental comparisonvalues (Law Environmental, Inc. 1993). Only limited numbersof remedial workers, contractors, and possibly installationpersonnel would have access to the area. Furtherinformation is included in the pathways analyses section.

Transitory Shelter (Building 202)--Reported DDT Spill Site

Soil
During early 1993, surficial and subfloor soil samples werecollected and analyzed to determine the level and extent ofpesticide contamination present at this location (LawEnvironmental, Inc. 1992b, Law Environmental, Inc. 1993). Soil samples were analyzed for VOCs, B/N/As,pesticides/PCBs, and total metals. The samples for VOCswere collected at the interval of 1-2 feet and samples forthe remaining parameters were collected at the interval of0-2 feet. Some pesticides (4,4'-DDD, 4,4'-DDE, and 4,4'-DDT) and total arsenic were the only compounds detectedabove environmental comparison values (Law Environmental,Inc. 1993). Only limited numbers of remedial workers,contractors, and possibly installation personnel would haveaccess to the area. Further information is included in thepathways analyses section.

Fuel Oil Storage Area

Groundwater
Groundwater samples were collected in the vicinity of this tank, during early 1993 to identify the nature and extent of contamination that may exist (Law Environmental, Inc. 1992b, Law Environmental, Inc. 1993). Groundwater samples were analyzed for VOCs, total petroleum hydrocarbons (TPH), B/N/As, total and dissolved metals, and pH. Some volatiles, some semi-volatiles, total lead, and total chromium were detected above environmental comparison values in monitoring wells for the Fuel Oil Storage Area (Table 8).
Soil
Subsurface soil samples were collected in the vicinity ofthis tank, during early 1993 to identify the nature andextent of contamination that may exist (Law Environmental,Inc. 1992b, Law Environmental, Inc. 1993). Five subsurfacesoil samples were collected at a depth of 1-3 feet. Sampleswere analyzed for VOCs, B/N/As, TPH, and total metals. SomePAHs (Benzo [a] anthracene, Benzo [a] pyrene, Benzo [b]fluoranthene, Benzo [f] fluoranthene, and Chrysene were theonly compounds detected above environmental comparisonvalues (Law Environmental, Inc. 1993). Only limited numbersof remedial workers, contractors, and possibly installationpersonnel would have access to the area. Furtherinformation is included in the pathways analyses section.

B. Off-Post Contamination

Groundwater
Water samples were collected and analyzed from private wells(Figure 4) in the Rayon Park area every two months from May1985 - September 1987. Information on depths of the wellswere not provided. The wells were tested for the presenceof VOCs, and the contaminants of concern detected in privatewells are listed in Table 9. Although well water wasanalyzed for metals at one residence, analyses for otherpertinent chemicals such as metals and PAHs were notconducted at the other residences. The one well that wastested for metals was not contaminated (Chesterfield HealthDistrict 1987). Until recently, the wells in the area hadnot been monitored since 1987, and data were not readilyavailable on numbers of private wells in use in the area.

However, one well in the Rayon Area (on Congress Street) wassampled in June of 1992. The well water was analyzed forvolatile organics, semi-volatile organics, metals, andpesticides/herbicides. No chemicals were detected aboveappropriate drinking water standards (DGSC 1993b).

Six private wells in the Kingsland Creek area (on KingslandRoad) were also sampled during June of 1992. The well waterwas analyzed for volatile organics, semi-volatile organics,metals, and pesticides/herbicides. One well had leaddetected at a concentration above EPA drinking waterstandards; five other wells in the immediate area did not. The lead has been attributed to the resident's well piping(DGSC 1993a). That homeowner was referred to a healthprofessional at the Virginia Department of Health (DGSC1993ba, DGSC 1993b).

Surface Water
Kingsland Creek surface water samples were collectedand analyzed quarterly from October 1981 to October1988. The ranges of concentrations of contaminants ofconcern that were detected in the surface water arelisted in Table 10. Samples were collected adjacent tothe Fire Training Area and downstream from installationproperty to determine the extent of migration from thesite (Dames and Moore 1989c).

Ambient aquatic 7-day chronic toxicity tests were conductedon water fleas and fathead minnows using water fromKingsland Creek. A benthic macroinvertebrate study also wasconducted. The creek was found to be moderately affected,possibly by the contaminants found in the creek (Dames andMoore 1989c). A definition of "moderately affected" was notprovided in the report.

In October of 1992, surface water samples were collectedboth on and off site from Kingsland Creek and were analyzedfor VOCs, B/N/A, pesticides/PCBs, total metals, TotalOrganic Carbon (TOC), cyanide, hexavalent chromium, andgrain size analysis (Law Environmental, Inc. 1993). Although some volatiles and total metals were occasionallydetected, adverse health effects are not likely.

Sediments
In 1985 and 1988, sediments from the creek were collectedand analyzed. Petroleum hydrocarbons were detected insediment samples from 56,000 - 68,000 ppb. The componentsof petroleum hydrocarbons were not provided (Dames and Moore1989c).

In October of 1992, sediment samples were collected both onand off site from Kingsland Creek and analyzed for volatileorganics (VOCs), base neutral/acid extractable semi-volatiles (B/N/A), pesticides/PCBs, total metals, cyanide,hexavalent chromium, total dissolved solids (TDS),conductance and pH (Law Environmental, Inc. 1993). Althoughsome pesticides and total metals were occasionally detected,adverse health effects are not likely.

C. Quality Assurance and Quality Control

The data reviewed by ATSDR are consistent with EPA guidelines. Data appear valid and reliable. However, for one chemical, vinylchloride, the detection limit (5 ppb) was higher than the MCL (2ppb) for groundwater collected from monitoring wells in the FuelOil Storage Area. This sampling was conducted in October of 1992(Law Environmental, Inc. 1993). For future sampling, thedetection limits should be set lower than regulatoryenvironmental comparison values. This public health assessmentwas prepared using the data presented in the RemedialInvestigation reports and other available documents.

D. Physical and Other Hazards

Although most drums stored at the Open Storage Area containlubricants with high flash points, some drums and containers,especially in the recoupment area, contain products with lowerflash points. During the March 1991 site visit, ATSDR staffheard some of the drums popping, and some of the drums wereunlabelled such that the flash points of the contents areunknown. Therefore, a physical hazard may exist at the open drumstorage area because weather-exposed drums could explode, orspills could result in fires. Only installation personnel haveaccess to those areas. EPA is currently working with theinstallation to resolve this situation (DGSC 1992b).


PATHWAYS ANALYSES

An environmental exposure pathway consists of the followingcomponents: 1) a source of contamination, such as the NationalGuard Area; 2) an environmental medium in which the contaminantsmay be present or may migrate, such as soil and groundwater; 3)points of human exposure, for example, private wells; 4) routesof exposure such as inhalation, ingestion, or dermal absorption;and 5) a receptor population, including people who are exposed orpotentially exposed. Pathways are considered to be complete whenall pathway components exist or are likely to exist. Pathwaysfor which one or more of the pathway components do not exist areconsidered 1) potential, if the missing component may beidentified at a later point in time; 2) potential, if the missingcomponent could occur at a later date; or 3) eliminated, if themissing component is likely never to occur. The past, present,and future exposure pathways that may present a public healthhazard are discussed in this section. Exposure pathwaysassociated with specific sites (source areas) may be completed,potential, or eliminated; therefore, each relevant medium isdiscussed in this section in relation to the sources ofcontamination.

A. Completed Exposure Pathways

Groundwater

The Open Storage Area and the National Guard Area havecontributed to upper aquifer contamination. Some introduction ofcontaminants to the lower aquifer through monitoring wellsconstructed during earlier investigations may have taken place,but that has not been confirmed by the installation contractors(Dames and Moore 1989b). Contaminants in Area 50 appear toaffect the lower aquifer. Contaminants from those three areasare believed to be linked to the off-post migration ofcontaminants to private wells in the northwestern corner of theRayon Park community (Figure 4). Current plume data do notconfirm if those three areas are also the source of other privatewell contamination in the community. Other potential sources ofcontamination exist in the community, such as the small body shopsouth of the installation in the Kingsland Creek area, but todate, no other source has been identified.

The private well contamination in Rayon Park resulted in acompleted exposure pathway for residents who used the water fordrinking and other household purposes. The exposure routes wereby ingestion and inhalation of, and dermal contact with thecontaminants. Contamination was first discovered in 1984;however, since 1987, wells with confirmed contamination have beenconnected to the municipal water supply. The exact duration andextent of exposure is unknown; the concentration of contaminantsmay have varied (i.e., higher or lower) over time. However,exposure has been confirmed for four years (1984 to 1987). Because the residents are using an alternate water supply, noexposures are believed to be taking place at this time. Pastexposures are evaluated in the Public Health Implicationssection.

B. Potential Exposure Pathways

Groundwater

Groundwater contamination is still present at the Open StorageArea, the National Guard Area, and Area 50. The contaminantplume or plumes that migrated from the installation to Rayon Parkcontinue to contaminate groundwater in that area and may migrateto other areas. In addition, at least three residences in thatarea have private wells that are still being used for drinkingwater and other household purposes. Those three wells weretested and showed no contamination in 1987, so the propertyowners elected to continue using those private wells. Althoughthose three wells have not been regularly monitored, one well inthat area was recently sampled in June of 1992. Well water wasanalyzed for volatile organics, semi-volatile organics, metals,and pesticides/herbicides. No chemicals were detected above EPAdrinking water standards (DGSC 1993b). Currently, it appearsthat wells in that area are probably free of contamination andare not being affected by contaminant plumes. Future exposuresare possible if contaminant plumes reach private wells that arestill in use. People who use the potentially contaminated waterwould be exposed by ingestion, inhalation, and dermal contact. An interim plan for remediation of groundwater east of theNational Guard Area is being proposed to prevent migration ofcontamination. It is expected to be released for public reviewin late April 1993 (DGSC 1993b).

Groundwater contamination in the Fire Training Area, according tothe Remedial Investigation, may be migrating toward homes southof the installation in the Kingsland Creek area (Dames and Moore1989c). In addition, there are other potential sources ofcontamination in that community such as a small body shop and alandscaping and nursery operation. Neighborhoods south of theinstallation appear to be topographically upgradient of KingslandCreek and a steep incline separates the installation from thehomes. However, analytical data in the Remedial Investigationsuggest that groundwater may flow under the creek toward thehomes. Some of those homes use private wells for drinking waterand other household purposes. There are no data that indicatethey were contaminated in the past. Recent sampling in theKingsland area in June of 1992 indicates they are currently freeof contamination, but future exposures are possible if wellsbecome contaminated by migrating contaminants. People who usethe potentially contaminated water would be exposed by ingestion,inhalation, and dermal absorption.

Contaminants of concern were detected in groundwater of the FuelStorage Area and Building 112. Because those sites are situatednear the Fire Training Area (Figure 3), groundwater flow isexpected to be to the south. Therefore, those sites may beadding contaminants to the groundwater pathway in that vicinity. That pathway is discussed in the paragraph above.

Soils

The original soils at the Fire Training Area were probablyBourne, a fine sandy loam. The soil has been graded and re-worked through the years, changing the original soil structure. The surface soils now consist of fine sandy loam; the subsoilconsists of friable sandy clay loam and brittle and compact finesandy loam. Because of the soil characteristics, lateral andsome limited vertical migration of contaminants may have takenplace. Contaminants of concern (see Table 5) have been measuredin soils at the Fire Training Area.

Installation personnel and remedial workers were and arepotentially exposed to the contaminants at the Fire TrainingArea. Potential exposure routes include incidental ingestion,inhalation, and dermal absorption. Restricting personnel'saccess to the site and providing them with appropriate, personal,protective equipment during remediation would diminish thepossibility of exposures.

Contaminants of concern were detected in soils sampled at theFuel Oil Storage Area and Buildings 202, 112, and 68. Installation personnel and remedial workers were and arepotentially exposed to the contaminants at those sites. Potential exposure routes include incidental ingestion,inhalation, and dermal absorption. Similar to the Fire TrainingArea, restricting personnel's access to the site and providingthem with appropriate, personal, protective equipment duringremediation would diminish the possibility of exposures.

Surface Water and Sediments

The central portion of the installation, which includes the AcidNeutralization Pits, the possible PCB Spill Area, the OpenStorage Area, Area 50, and the National Guard Area, drains towardthe No-Name Creek north and northeast of the National Guard Area. The No-Name Creek originates at the outfall of the storm sewersystem on the installation and flows south/southeast, through theRayon Park subdivision, until it empties into the James Riverabout two miles from the installation. Contaminants from thestorm sewer, shallow groundwater, and runoff are transported fromthe installation by this creek. The creek and sediments havebeen contaminated by the previously named sites. Metals, VOCs,and PAHs were detected in the surface water of the No-Name Creekon the installation; no contaminants were found above detectionlimits off site. Petroleum hydrocarbons were detected insediment of the No-Name Creek on the installation. People whowade or swim in the No-Name Creek, which flows from the NationalGuard Area through the Rayon Park subdivision, may potentially beexposed to contaminants by incidental ingestion and inhalation ofand dermal absorption of contaminants, if contaminants were tomigrate off of DGSC. However, recent surface water and sedimentsampling both on and off site in No-Name Creek were conducted inOctober of 1992 (Law Environmental, Inc. 1992b and LawEnvironmental, Inc. 1993). Although some chemicals weredetected, the concentrations are not likely to cause adversehealth effects.

Kingsland Creek flows along the southern border of theinstallation. Runoff and groundwater from the Fire TrainingArea, Aluminum Phosphide Residue Disposal Area, and Building 202--Reported DDT Spill Site discharge into the creek. The creekempties into the James River about 2.5 miles east of DGSC. Anarea about 170 feet south of the Fire Training Area receivesgroundwater discharge during periods of high water tableconditions resulting in intermittent surface water conditions. The water drains to Kingsland Creek by way of a culvert. Two VOCs, TCE and PCE, have been detected at low concentrations inthe surface water of Kingsland Creek. Anyone who fishes or playsin the creek could be exposed to the contaminants possibly byingestion, inhalation, and dermal contact. Low levels of PCE andTCE detected thus far are not of public health concern. Recentsurface water and sediment sampling both on and off site inKingsland Creek were conducted in October of 1992 (LawEnvironmental, Inc. 1992b and Law Environmental, Inc. 1993). Although some chemicals were detected, the concentrations are notlikely to cause adverse health effects.

Air

Prevailing winds in the DGSC area were reported in the RemedialInvestigations to be southerly. Wind speeds in the area aregenerally moderate, except during storms. No air sampling hasbeen conducted to determine the degree of off-post migration ofcontaminants as gases or particulates.

However, soil gas data indicate that total VOCs are present atthe National Guard Area. Therefore, a potential exposure pathwayexists for installation personnel working in this area and fornearby residents in Rayon Park. The route of exposure would beprimarily by inhalation of air in buildings and surroundinggrounds. Accumulation of concentrations of VOCs of public healthconcern is unlikely because the concentrations of total VOCsdetected in soil gas are very low (concentrations ranged from 1to 84 ppb of total VOCs). Individual VOCs at the National GuardArea were not measured because concentrations of individualcontaminants were below detection limits for the equipment used. However, due to the rapid volatility of VOCs and the low levels(ranging from 1 to 84 ppb) of total VOCs detected in the soilgas, exposure levels are not expected to be of public healthconcern.

Soil gas data confirm the presence of VOCs at the Fire TrainingArea (Table 5). Installation personnel and remedial workerscould be exposed to VOCs by inhalation. The residence nearest tothe Fire Training Area is beyond steep inclines, approximately0.25 miles away, and residents are not likely to be exposed toVOCs under normal climatic conditions.

Although most drums stored at the Open Storage Area containlubricants with high flash points, some drums and containers,especially in the recoupment area, may contain products withlower flash points. During a March 1991 site visit, ATSDR staffnoticed that some of the drums were popping and that some drumswere unlabelled, thereby making their contents, and consequently,their flash points, unknown. Therefore, a physical hazard mayexist at the Open Storage Area because weather-exposed drumscould explode, or spills could result in fires. The installationis working with EPA to resolve this situation (DGSC 1992b).

C. Eliminated Exposure Pathways

Groundwater

Groundwater flow from the Acid Neutralization Pits appears to benorth or east. The Remedial Investigation for the AcidNeutralization Pits indicate the shallow and deep aquifers atthis site may be distinct or separate (Dames and Moore 1989a). Creeks lie to the north and east, and the pits are near thecentral/north central portion of the installation (Figures 1 and3). Contaminants of the Acid Neutralization Pits are notsuspected to be those detected in the private wells of the RayonPark community nor are they likely to migrate to other homeswhere wells are used. The Rayon Park wells appear to be affectedby contaminants from other sites (the Open Storage Area/NationalGuard Area/Area 50) on the installation (Dames and Moore 1989b). Therefore, no completed exposure pathways are expected to resultfrom the groundwater contamination at the Acid NeutralizationPits.

Soils

No contaminants of concern have been detected in soil at allsites studied to date, except for the Fire Training Area, FuelOil Storage Area, and Buildings 202, 112, and 68. Therefore,except at those sites, no completed exposure pathways associatedwith ingestion and inhalation of dust particles and dermalcontact with the soils are expected.

Surface Water and Sediments

Drainage from the northern portion of the installation is towardFalling Creek, which is about one mile northeast of the AcidNeutralization Pits. Runoff, drainage, and groundwater dischargeare not likely to affect Falling Creek. Therefore, no completedexposure pathways associated with people swimming or wading inthe creek are expected.

Parker Pond is in the southern portion of the facility, north ofthe Fire Training Area. The pond is reported to be used forrecreational fishing, not subsistence fishing, by installationpersonnel (DGSC 1991a and DGSC 1992b). Parker Pond probably doesnot receive runoff from the sites discussed in this document. However, it does receive roadway runoff and is being investigatedfor possible pesticide contamination as discussed in the On-SiteContamination section of this document. Since the pond is notused for swimming (DGSC 1991a and DGSC 1992b) and data provided(DGSC 1991b) to date do not indicate the presence of contaminantsin surface water or sediments, no exposures to contaminants areexpected.

Air

According to interviews with installation personnel, no reactivealuminum phosphide is expected to be present at the AluminumPhosphide Residue Disposal Area (DGSC 1992b). Therefore, noexposures by inhalation are expected. (Aluminum phosphide is notexpected to be present at the area, because the material disposedof in this area was residue from reacted pellets of aluminumphosphide.)

Biota

In the summer of 1987, there was a fish kill in Parker Pond. Thefish kill was believed to be the result of low oxygenconcentrations in the pond because dissolved oxygen was measuredat levels below those normally needed to support fish. However,a fish was analyzed for pesticides. The dead fish, stocked fromanother source, contained 260 ppb of DDT (DGSC 1991a, DGSC 1991b,and DGSC 1992b). In 1988 and 1991, surface water and sedimentsamples were collected and analyzed for pesticides. Nopesticides were measured in those samples (DGSC 1991b). Findingsfrom the surface water and sediment sampling suggest that DDT wasnot introduced into the fish from the pond (DGSC 1991b). Becausethe fish used to stock the pond are brought from an off-postfacility (DGSC 1992b), the fish could have been contaminatedbefore they were put into the pond. However, fish in the pondand fish from the hatchery should be sampled for confirmation. The facility is now stocking the pond with fish from anothersource.

Edible biota that may be affected by contaminants detected atDGSC include fish from Kingsland Creek and plants from small homegardens. Although no fish tissue from Kingsland Creek has beencollected, the types of contaminants (Table 10) found to date inthe creek are not likely to be taken up into the fish at levelsof concern (ATSDR 1992b, ATSDR 1992c, Law Environmental, Inc.1993). Therefore, eating fish from Kingsland Creek is notconsidered a potential exposure pathway.

To date, no vegetation samples have been collected and analyzed. However, the types of contaminants detected in private wells thatmay still be used for irrigation are not likely to be taken up bythe plants at levels of concern. Available data indicate thatplants grown near the facility are not expected to be an exposurepathway. Future private well data may indicate a need to re-evaluate that conclusion.


PUBLIC HEALTH IMPLICATIONS

A. Introduction

In this section, ATSDR discusses health effects that could resultfrom exposures to site contaminants. People can only be exposedto a site contaminant if they come in contact with it. Peoplecan be exposed by breathing, eating, or drinking the contaminant,or by contacting (skin) contaminated water, soil, or air.

In order to understand health effects that may be caused by aspecific chemical, it is helpful to review factors related to howthe human body processes the chemical after exposure. Thosefactors include the exposure concentration (how much), theduration of exposure (how long), the route of exposure(breathing, eating, drinking, or skin contact), and themultiplicity of exposure (combination of contaminants). Onceexposure occurs, individual characteristics such as age, sex,nutritional status, health status, lifestyle, and geneticsinfluence how the chemical is absorbed, distributed, metabolized(processed), and excreted (eliminated). Together, those factorsdetermine health effects that exposed people may have.

To determine the possible health effects of specific chemicals,ATSDR searches scientific literature. The resulting informationis compiled and published in a series of chemical-specific ATSDRdocuments called Toxicological Profiles. Toxicological Profilesare references that describe adverse health effects that could beassociated with exposure to a specific chemical in theenvironment. In addition, they include health guidelines such asATSDR's minimal risk levels (MRLs) and EPA's reference doses(RfDs), reference concentrations (RfCs), and cancer slope factors(CSFs). When RfDs, RfCs, and MRLs are not available, a noobserved adverse effect level (NOAEL) or lowest observed adverseeffect level (LOAEL) may be used to estimate levels at whichadverse noncancerous effects are not expected.

ATSDR compares contaminant concentrations in differentenvironmental media (soil, air, water, and food) that populationsmay be exposed to daily to a variety of health guidelines. Thiswill determine whether exposure to given levels of contaminantsis likely to cause an increased risk of developing cancer and/ornoncancerous adverse health effects. ATSDR's MRL is an estimateof daily human exposure to a chemical likely to be withoutappreciable risk of deleterious effects (noncancerous) over aspecified duration of exposure. MRLs are based on human andanimal studies and are reported for acute (less than or equal to14 days), intermediate (15-364 days), and chronic (greater thanor equal to 365 days) exposures. If an individual's dailyexposure is below the MRL, adverse health effects are notexpected. A RfD is EPA's estimate for the human population,including sensitive subpopulations, of the daily exposure by theoral route likely to be without appreciable risk of deleteriousnoncarcinogenic effects during a lifetime (70 years). Likewise,a RfC is EPA's estimate for the human population, includingsensitive subpopulations, of the daily exposure by the inhalationroute likely to be without appreciable risk of deleteriousnoncancerous effects during a lifetime (70 years).

A NOAEL or LOAEL may be used when RfDs, RfCs, and MRLs are notavailable. That level is used to estimate a dose at whichneither animals nor people would be expected to develop adversenoncancerous effects.

Some health guidelines such as MRLs and RfDs do not consider,however, the risk of developing cancer. To evaluate exposure tocarcinogenic chemicals, EPA has established cancer slope factors(for inhalation and ingestion) that define the relationshipbetween exposure doses and the likelihood of an increased risk ofcancer compared with non-exposed controls. Usually derived fromanimal or occupational studies, cancer slope factors are used tocalculate the exposure dose likely to result in one excess cancercase per one million persons exposed over a lifetime (70 years).

ATSDR's estimation of human exposure to contaminated media usesmedia-specific rates for adults and children. The rates arecalculated by multiplying contaminant concentration by theingestion rate for an adult or a child, and then dividing thatnumber by the appropriate standard body weight (70 kg for adults,16 kg for a child). The water ingestion rates used for adultsand children are 2.0 L/day and 1.0 L/day, respectively. ATSDRuses an inhalation rate of 23 cubic meters per day (m3/day) foradults and 15 m3/day for children. Some exposures occur on anintermittent or irregular basis; in those cases, an exposurefactor (EF) is calculated that averages the dose over theexposure period.

The maximum contaminant concentration detected in a particularmedium is used to determine estimated exposure. Using themaximum concentration results in an evaluation that is protectiveof public health.

Individuals off site have been exposed to multiple chemicals bydirect ingestion of water from contaminated private wells. Dataare very limited, however, on the health effects of multiplechemical exposures by oral, dermal, and inhalation routes. Effects of specific contaminants detected in multiple media canbe additive, antagonistic, or synergistic, i.e., adverse healtheffects may be increased, decreased, or one effect may becancelled by another. Furthermore, simultaneous exposure tocontaminants that are known or probable human carcinogens couldincrease the risk of developing cancer and/or noncancerous healtheffects. ATSDR's evaluation of exposures in this public healthassessment is limited to individual contaminants and individualroutes of exposure; multiple exposures have not been evaluated. Current research involving complex chemical mixtures eventuallywill add new information that will be used in future evaluations.

B. Toxicologic Evaluation

The private well contamination in the Rayon Park neighborhood,north and east of DGSC, is a past completed exposure pathway forresidents who used the water for drinking and other householdpurposes (Table 9). Contaminants detected in private well waterwere the following VOCs: benzene, 1,2-dichloroethane, 1,1-dichloroethylene, tetrachloroethylene, 1,1,1-trichloroethane, andtrichloroethylene. Contaminants from the Open Storage Area,National Guard Area, and Area 50 may be linked to the off-postmigration of contaminants to private wells in the northwesterncorner of the Rayon Park community.

Except for Rayon Park, residents of communities near DGSC appearto have a high rate of residential mobility. The CommunityRelations Plan reports that residents of Rayon Park tend to beless transient when compared to other persons in the surroundingarea (Virginia Department of Waste Management 1991). Contamination was first discovered in Rayon Park wells in 1984;however, since 1987, wells with confirmed contamination have beenreplaced with municipal water supply. The exact duration andextent of exposure is unknown; the concentration of contaminantsmay have varied (i.e., higher or lower) over time. However,exposure has been confirmed for four years (1984 to 1987). Thefollowing paragraphs evaluate the potential health effects ofcontaminant exposure (via ingestion, inhalation, and dermalcontact) to individual contaminants.

Benzene

Residents of the Rayon Park community (off-site) were exposed tobenzene by ingesting benzene-contaminated water from theirprivate wells. Exposure to benzene by both inhalation andingestion may have taken place. Although dermal exposure waspossible, dermal absorption of benzene is likely to be minimal,i.e., less than 1% of the concentration (Franz 1984, Mailbach andAnjo 1981, Susten et al 1985, ATSDR 1992a). Therefore, dermalabsorption of benzene is not a significant route of exposure forresidents who used that contaminated well water.

Benzene has been detected in residential wells at a maximumconcentration of 1.4 ppb (parts per billion). EPA has classifiedbenzene as a known human carcinogen by oral and inhalationroutes. In industrial settings, chronic benzene exposureadversely affects the body's ability to make red and white bloodcells, which may eventually lead to aplastic anemia and acutemyeloblastic leukemia (ATSDR 1992a). The concentrations, andthus exposure doses, of benzene encountered in those settings aremuch higher than those detected in Rayon Park wells. Therefore,exposures at Rayon Park are not expected to result in anincreased cancer risk because of the infrequent, low levels ofbenzene detected in the Rayon Park wells. The duration ofexposure is unknown.

Health guidelines, such as the RfC and RfD, for benzene areundergoing review by an EPA work group. Most of the informationabout noncancerous health effects associated with benzeneexposure in humans is from studies of workers employed byindustries that make or use benzene. The concentrations, andthus exposure doses, of benzene encountered in those settings(ATSDR 1992a) are much higher (approximately 500- to 700- foldhigher) than those detected in Rayon Park wells.

Assuming the estimated exposures associated with inhalation ofvolatilized benzene from activities such as showering and cookingare approximately equal to estimated ingestion exposures (Otto1990 and McKone 1987), adverse noncancerous health effects arenot expected from inhalation of volatilized benzene from RayonPark wells. Although it appears that the blood and immune andcentral nervous systems are adversely affected by chronic benzeneinhalation, the levels at which those effects have been observedare much higher than levels of benzene detected in the Rayon Parkwells (1.4 ppb). For example, a study in a Texas refinery showedno changes in blood components (platelets, red blood cells, whiteblood cells, hemoglobin, or hematocrit) in workers who inhaledbenzene at levels less than 1,000 ppb (the mean was 530 ppb) for1-21 years (Tsai et al 1983).

Health guidelines, such as MRLs and RfDs, have not beenestablished for noncancerous health effects in people followingchronic oral exposure to benzene. However, results from animalstudies suggest that chronic oral exposure to benzene adverselyaffects the liver, kidneys, blood and the immune and centralnervous systems. However, those effects are seen at levelsbetween 100 to 1,000 times higher than the maximum level ofbenzene detected in private wells in Rayon Park (ATSDR 1992a). Therefore, noncancerous health effects are unlikely.

Benzene is a VOC used in the production of plastics, detergents,pesticides, lubricants, dyes, and some types of rubber. It alsois a component of gasoline, vehicle exhaust fumes, and tobaccosmoke (ATSDR 1992a). The general population is exposed tobenzene mainly through inhalation of contaminated air(particularly in areas of heavy traffic and around gas stations)and tobacco smoke (from both active and passive smoking). Smoking is the single most important source of benzene exposurefor the estimated 40 million U.S. smokers; smoking accounts forapproximately half of the total benzene exposure of the generalpopulation. Individuals employed by industries that make or usebenzene or products containing benzene are probably exposed tothe highest concentrations of atmospheric benzene (ATSDR 1992a). People who used their contaminated well water for drinking andother household uses may have had exposures to benzene other thanfrom their private wells. Those persons residing in Rayon Parkwho were smokers or employed in occupations using benzene in theworkplace may have had additional exposures to benzene.

People who used the contaminated wells in Rayon Park and may havebeen particularly sensitive to benzene during that time ofexposure include pregnant women, their fetuses, andimmunosuppressed and malnourished people (ATSDR 1992a). Whetherthose populations have different or enhanced responses depends onthe ability of the liver and kidneys, and other target organssuch as the bone marrow, to detoxify and excrete benzene. Thebone marrow produces white blood cells, which as part of theimmune system, help to guard against disease. For those reasons,it is expected that persons who were using contaminated wells inRayon Park and were either elderly people with declining organfunction or young children with immature and developing organsmay have been more vulnerable to benzene and other toxicsubstances than healthy adults (ATSDR 1992a). Rayon Park areacurrently consists of about sixteen percent of persons 65 yearsof age or older and nine percent under age 10 (Table 1--1990Census Data). Since that area is fairly stable, or lesstransient than other areas, it is likely that thosesubpopulations were also present during the years when exposuresto contaminated well water were occurring.

1,2-Dichloroethane (1,2-DCA)

Residents of Rayon Park were exposed to 1,2-DCA by inhalation andingestion of and dermal contact with 1,2-DCA-contaminatedgroundwater from their residential wells. People are exposed to1,2-DCA mainly by breathing it in air or by drinking it in 1,2-DCA-contaminated water. However, if drinking water suppliescontain more than 6 ppb of 1,2-DCA, exposure by ingestion isexpected to be more significant than inhalation (EPA 1985). Because of the high vapor pressure of 1,2-DCA, it rapidlyvolatilizes thereby making dermal contact an insignificant routeof exposure for residents of Rayon Park (Tsurata 1975, EPA 1985,ATSDR 1989a).

A maximum concentration of 6.2 ppb of 1,2-DCA was detected inRayon Park well water. Little information exists about thedevelopment of cancer in people following long-term exposure to1,2-DCA. Using animal studies, however, EPA has classified 1,2-DCA as a probable (B2) human carcinogen (NCI 1978, Van Duuren etal 1979, ATSDR 1989a) by both ingestion and inhalation routes. Those studies indicate that 1,2-DCA has caused numerous types oftumors in a variety of animals. However, exposures at Rayon Parkare not expected to result in an increased cancer risk because ofthe infrequent, low levels of 1,2-DCA detected in the Rayon Parkwells. The duration of exposure is unknown.

There are no health guidelines for noncancerous health effects inpeople caused by chronic exposure via ingestion or inhalation of1,2-DCA. However, in a study of the effects of intermediateexposures, (Munson et al 1982), mice were given 1,2-DCA-contaminated water for consumption for approximately 90 days. The results showed 189,000 µg/kg/day to be the NOAEL for adverseliver effects in mice. Applying a uncertainty factor of 1000(which would account for animal-human variability, durationvariability, and human subpopulation variability), that valuewould correspond to 189 µg/kg/day in people. The daily estimatedingestion dose for adults and children in Rayon Park is 0.18µg/kg/day and 0.39 µg/kg/day, respectively. Assuming theinhalation dose would be approximately equal to the ingestiondose (McKone 1987 and Otto 1990), noncancerous effects to theliver would not be expected from past exposure via ingestion andinhalation of the contaminated water due to activities such asdrinking and showering and cooking, respectively.

1,2-DCA is a clear, synthetic liquid used primarily to make vinylchloride and several solvents that remove grease, glue, and dirt. It also is added to leaded gasoline to remove lead. In the past,it was a component of some cleaning solutions and pesticides;some adhesives, such as those used to glue wallpaper orcarpeting; and some paint, varnish, and finish removers (ATSDR1989a). Automobile and heavy equipment mechanics, machinists,janitors, and registered nurses are frequently exposed to 1,2-DCAin the workplace (ATSDR 1989a). The National OccupationalExposure Survey conducted by the National Institute ofOccupational Safety and Health notes that workers are exposed to1,2-DCA when it is used as a fumigant, solvent, or diluent inopen-system operations (ATSDR 1989a). People with 1,2-DCA-contaminated wells in Rayon Park may have additional exposures to1,2-DCA, if they were employed in the occupations or industriespreviously discussed.

Persons who were exposed to 1,2-DCA-contaminated wells and weretaking the medications disulfiram or phenobarbital, used to treatalcoholism and seizures respectively, may have been highlysensitive to the effects of 1,2-DCA (ATSDR 1989a). Those drugsmay alter a person's metabolism, resulting in increased levels ofthe active metabolites of 1,2-DCA. Reduced hepatic glutathione(GSH) also may alter the excretion of active metabolites. GSHplays a protective role in the liver by helping the body excreteactive metabolites of 1,2-DCA. Reduced nutritional intake, suchas fasting, can result in lowered GSH levels, which, as shown inanimal studies, may dramatically slow the excretion of 1,2-DCA(ATSDR 1989a).

1,1-Dichloroethylene (1,1-DCE)

People have been exposed to 1,1-DCE via ingestion and inhalationof, and dermal contact with 1,1-DCE-contaminated water from RayonPark wells. All three exposure routes are believed to be equallysignificant with regard to absorption of 1,1-DCE based on reportsin the literature (ATSDR 1989b).

A maximum concentration of 41 ppb of 1,1-DCE was detected inRayon Park well water. Children and adults exposed to 41 ppb of1,1-DCE would have estimated ingestion exposures of 2.56µg/kg/day and 1.17 µg/kg/day, respectively. Reports in theliterature indicate that an increased cancer risk wasdemonstrated in one animal study involving inhalation exposure to1,1-DCE (ATSDR 1989b). Most studies have shown, however, that1,1-DCE does not cause cancer in animals, and no evidencesuggests that 1,1-DCE is carcinogenic to people. However, EPAhas classified 1,1-DCE as a possible (Group C) human carcinogenusing animal studies (ATSDR 1989b). That category applies tochemical agents for which there is limited evidence ofcarcinogenicity in animals and no evidence in people. Exposuresat Rayon Park are not expected to result in an increased cancerrisk because of the infrequent, low levels of 1,1-DCE detected inthe Rayon Park wells. The duration of exposure is unknown.

Adverse noncancerous effects are not expected to result fromingestion of 1,1-DCE because the levels detected in private wellwater in Rayon Park would result in estimated exposure doses (of2.56 µg/kg/day and 1.17 µg/kg/day for children and adults,respectively) which are below the minimal risk level (MRL) of 9µg/kg/day. The MRL is the estimated level below which adversenoncancerous effects are not expected.

Assuming the estimated exposures from inhalation of volatilized1,1-DCE from showers and cooking are approximately equal toestimated ingestion exposures (Otto 1990 and McKone 1987), noadverse noncancerous health effects are expected from inhalationof volatilized 1,1-DCE from Rayon Park wells. The estimatedexposures of 2.36 µg/kg/day and 0.83 µg/kg/day in children andadults, respectively, are below the MRL of 9 µg/kg/day.

Although it is recognized that dermal contact with 1,1-DCE alsois another route of exposure, (ATSDR 1989b) health guidelinessuch as MRLs have not been established for dermal exposure. Dermal contact can result from household activities such asshowering, mopping, washing dishes, and washing cars with 1,1-DCE-contaminated water. However, assuming all three exposureroutes (ingestion, inhalation, and dermal contact) are equallysignificant with regard to absorption of 1,1-DCE (ATSDR 1989b)and assuming the estimated exposures from ingestion of 1,1-DCE inwell water would be approximately equal to estimated dermalexposures, no adverse health effects are expected from dermalcontact with 1,1-DCE contaminated water. The estimated exposuresof 2.36 µg/kg/day and 0.83 µg/kg/day in children and adults,respectively, are below the MRL of 9 µg/kg/day.

Also known as vinylidene chloride, 1,1-DCE is used to makevarious plastics, such as packaging materials (flexible films,e.g., plastic food wraps) and flame-retardant fabrics (ATSDR1989b). A national survey conducted by NIOSH (1976) estimatedthat the largest numbers of workers potentially exposed to DCE inthe workplace were special trade contractors or workers in thefabricated metal products or wholesale trade industries. Theoccupational groups with the largest numbers of exposed workerswere carpenters, warehousemen (not otherwise classified), andmiscellaneous machine operators (ATSDR 1989b). Residents ofRayon Park who were employed by those industries may have hadexposures to 1,1-DCE besides those from their private wells.

Although information about populations that may be especiallysensitive to 1,1-DCE is from animal studies, it is believed thatthe following groups may have been particularly susceptible toits toxic effects during the time the contaminated wells wereused: infants and young children, pregnant women, consumers ofalcohol, people with liver, kidney, thyroid and cardiac disease,certain central nervous system dysfunctions, and people who arefasting (ATSDR 1989b). Increased susceptibility to 1,1-DCEtoxicity is largely caused by the formation of toxicintermediates during its metabolism (ATSDR 1989b).

Tetrachloroethylene (PCE)

Residents of Rayon Park were exposed to PCE when they ingestedPCE-contaminated water. Although the primary route of exposureto PCE is inhalation (Hake and Stewart 1977), PCE also isabsorbed following ingestion (Koppel et al 1985). Dermalabsorption of PCE in people is not as significant as absorptionby inhalation (ATSDR 1992b); thus, dermal contact withcontaminated water from Rayon Park wells is not a significantroute of exposure.

PCE was detected at a maximum concentration of 4.9 ppb in privatewell water of Rayon Park. People have been exposed to PCE in thepast by way of ingestion and inhalation of and dermal contactwith PCE-contaminated water. The EPA has classified PCE as aprobable (B2) human carcinogen by oral and inhalation routesbecause of results from animal studies (ATSDR 1992b). However,exposures at Rayon Park are not expected to result in anincreased cancer risk because of the infrequent, low levels ofPCE detected in the Rayon Park wells. The duration of exposureis unknown.

For PCE, ATSDR has calculated an intermediate MRL for inhalationexposure to be 9 ppb or 1.18 µg/kg/day for children and 0.41µg/kg/day for adults. The estimated daily ingestion exposures ofRayon Park children and adults exposed to a concentration of 4.9ppb PCE are 0.31 µg/kg/day and 0.14 µg/kg/day, respectively. Assuming that the estimated exposures from inhalation ofvolatilized PCE from household activities, such as showering andcooking, are approximately equal to estimated ingestion exposures(Otto 1990 and McKone 1987), adverse noncancerous health effects--such as damage to the lungs, liver, kidneys, and centralnervous system (ATSDR 1992b)-- would not be expected frominhalation of volatilized PCE from water in Rayon Park wells.

Adverse noncancerous effects from ingestion of PCE, such asdamage to the central nervous system, liver, and kidneys, are notexpected in Rayon Park residents, because the levels detected intheir wells would result in estimated exposure doses below theoral RfD of 10 µg/kg/day (ATSDR 1992b).

There are no health guidelines for noncancerous health effects inpeople caused by chronic dermal contact with PCE. However,intense ocular irritation has been reported in people who havebeen exposed to PCE vapor at concentrations greater than 1,000ppm (Carpenter 1937 and Rowe et al 1952). Burning or stingingsensations in the eyes occurred after exposure to greater than280 ppm (Rowe et al 1952). Those concentrations areapproximately 100-fold greater than levels expected fromvolatilized PCE associated with activities such as from showeringand cooking. Therefore, no adverse noncarcinogenic healtheffects are expected from dermal contact with PCE.

PCE is a synthetic solvent used widely for dry cleaning fabricsand textiles and in metal-degreasing operations (ATSDR 1992b). General uses of PCE include carrier applications for rubbercoatings, solvent soaps, printing inks, adhesives and glues,sealants, polishes, lubricants, and silicones (Chemical ProductsSynopsis 1985 and Mitchell 1980). Persons employed in industriesusing PCE, previously discussed, may be exposed to PCE in theworkplace. Thus, residents of Rayon Park who were employed bythose industries may have had exposures to PCE besides theexposures from their private well water. PCE can cross theplacenta and has been found in breast milk, but the exposuredoses in the mothers were unknown. Therefore, fetuses andnursing babies may have been at an increased risk for adversehealth effects from maternal exposure, if their mothers consumedcontaminated water from Rayon Park wells (ATSDR 1992b).

1,1,1-Trichloroethane (1,1,1-TCA)

Rayon Park residents were exposed to 1,1,1-TCA when they ingestedand inhaled contaminated water from their private wells. Although dermal exposure is possible, dermal absorption of 1,1,1-TCA is likely to be minimal compared with inhalation (Tsurata1975); most of it evaporates into the air (ATSDR 1990). Therefore, dermal absorption is not a significant route ofexposure for Rayon Park residents.

A review of the literature found no exposure studies in animalsor people that have conclusively shown 1,1,1-TCA is a carcinogen(Quast et al 1988). Therefore, at this time, 1,1,1-TCA is notconsidered to be carcinogenic. A maximum concentration of 500ppb was detected in Rayon Park wells. The estimated dailyexposures from ingestion of 500 ppb of 1,1,1-TCA is 31.3µg/kg/day for children and 14.3 µg/kg/day for adults.

Health guidelines have not been established for noncancerouseffects in people after chronic inhalation and ingestion of anddermal contact with 1,1,1-TCA. But, a long-term occupationalstudy found a NOAEL for central nervous system effects thatranged from 200,000 - 900,000 ppb of 1,1,1-TCA (Maroni et al1977). The study focused on inhalation exposures with an averageduration of 6.7 years per study group. Using the lowerconcentration of 200,000 ppb, an estimated inhalation dose foradults would be 21,459 µg/kg/day; for children, it would be 7,521µg/kg/day. Assuming the inhalation and ingestion dosesassociated with the contaminated water were approximately equal(Otto 1990 and McKone 1987) and using the NOAEL from theoccupational study, adverse noncancerous effects would not beexpected.

No studies were found that investigated chronic ingestion of1,1,1-TCA by people. However, one study (Maltoni et al 1986) ofsystemic effects from chronic ingestion of 1,1,1-TCA by ratsestablished a NOAEL of 500,000 µg/kg/day. Using that informationand assuming the inhalation and ingestion doses would beapproximately equal, adverse noncancerous effects would not beexpected.

Results from animal studies indicate that nicotine enhances thelethality of 1,1,1-TCA (Priestly and Plaa 1976), suggesting thatsimultaneous exposure to nicotine and 1,1,1-TCA could pose anincreased health risk in people. Therefore, smokers exposed to1,1,1-TCA could have an increased risk for adverse health effectscompared with nonsmokers. Low doses of ethanol (found inalcoholic beverages) also tend to enhance the lethality of 1,1,1-TCA (Woolverton and Balster 1981), suggesting that increasedhealth risks may be associated with simultaneous exposure tothose two chemicals. Because of that, alcoholics exposed to1,1,1-TCA could also have an increased risk for adverse healtheffects. Phenobarbital, which is prescribed for certain cases ofepilepsy, reportedly enhances the hepatotoxicity of 1,1,1-TCA inrats (Carlson 1973). Thus, an increased risk of hepatotoxicitymay be associated with simultaneous exposure to that drug and1,1,1-TCA. Moreover, people who have cardiac arrhythmias alsomay be more susceptible to the health effects of 1,1,1-TCA (ATSDR1990). Persons belonging the groups previously described and whoalso were exposed to 1,1,1-TCA in Rayon Park contaminated wellwater may have been more susceptible to the adverse healtheffects from 1,1,1-TCA exposure (Byers et al 1988, Lagakos et al1986, Mallin 1990, Vinels 1990, Hong et al 1991, Hernberg et al1988).

1,1,1-TCA is a synthetic chemical with many industrial andhousehold uses. It is often used as a solvent to dissolve othersubstances, e.g., glue and paint. In industry, it is widely usedto remove oil and/or grease from manufactured metal parts. Italso may be in household products such as spot cleaners, glues,and aerosol sprays (ATSDR 1990). Residents of Rayon Park whowere employed by those industries may have had additionalexposures to 1,1,1-TCA other than exposures from their privatewell water.

Trichloroethylene (TCE)

Rayon Park residents were exposed to TCE when they ingestedcontaminated water from their private wells. Ingestion andinhalation of and dermal contact with the contaminated water werethe routes of exposure. Dermal contact seems to be moresignificant as a route of exposure if large amounts are appliedon the skin, which might happen in an occupational setting (ATSDR1992c). Therefore, dermal contact is not a significant route ofexposure for Rayon Park residents who used contaminated wells forhousehold uses.

Water samples collected from private drinking water wells nearDGSC contained a maximum concentration of 5.2 ppb TCE. Theestimated daily exposures of Rayon Park children and adultsingesting a concentration of 5.2 ppb TCE are 0.33 µg/kg/day and0.15 µg/kg/day, respectively. The International Agency forResearch on Cancer and EPA are evaluating TCE's carcinogenicity(ATSDR 1992c) because only one animal study has found TCE tocause cancer. However, EPA has classified TCE as a probablehuman carcinogen by oral and inhalation routes. However,exposures at Rayon Park are not expected to result in anincreased cancer risk because of the infrequent, low levels ofTCE detected in the Rayon Park wells. The duration of exposureis unknown.

ATSDR has derived an intermediate MRL of 100 µg/kg/day foringestion of TCE. The estimated ingestion doses describedpreviously do not exceed the MRL of 100 µg/kg/day. Therefore,adverse noncancerous health effects are not expected.

There currently are no health guidelines, such as an MRL or RfC,for people who have been exposed to TCE via inhalation. Reportsin the literature indicate that estimated exposures frominhalation of volatilized TCE from activities, such as showeringand cooking, is approximately equal to estimated ingestionexposures (Otto 1990 and McKone 1987). Thus, adversenoncancerous health effects are not expected because theingestion dose of 0.33 µg/kg/day for children and 0.15 µg/kg/dayfor adults does not exceed the ATSDR intermediate MRL of 100µg/kg/day.

Dermal contact with the concentrations of TCE found in Rayon Parkwell water is not expected to result in adverse health effects. The literature reports that skin irritations, burns, and rasheshave been seen in workers with occupational exposure to TCE(Bauer and Rabens 1974 and Goh and Ng 1988). The dermal effectsmentioned previously are usually the consequence of direct skincontact with concentrated solutions, and those levels are muchhigher than (100- to 10,000-fold) those detected in Rayon Parkwell water. Although adverse effects have not been reported fromexposure to dilute aqueous solutions (ATSDR 1992c), those levels have not been measured.

Persons particularly susceptible to TCE exposures are chronicconsumers of alcohol, people with heart disease, people takingdisulfiram (a medication used to treat alcoholism), and peopletaking the anticoagulant warfarin (ATSDR 1992c). Thosemedications increase the toxicity of TCE in the liver byinterfering with its normal metabolism. Thus, residents usingRayon Park contaminated wells and belonging to the above groups may have been more susceptible to the health effects from TCEexposure.

According to the literature, TCE exposure usually occurs inoccupational settings where the chemical is used as a solvent toremove grease from metal parts (ATSDR 1992c). Products that maycontain TCE are some types of typewriter correction fluids,paints and paint removers, glue, spot removers, rug-cleaningfluids, and metal cleaners (ATSDR 1992c). Thus, residents ofRayon Park who were employed by those industries may have hadadditional exposures to TCE other than those exposures from usingcontaminated water from private wells.

Summary

Some Rayon Park residents have been exposed to six different VOCsby way of ingestion and inhalation of and dermal contact withVOC-contaminated water from their private wells. Because ofinfrequent exposure to low levels of VOCs in those wells, adversehealth effects are not expected. The actual duration of thosepast exposures is unknown, and the exposures stopped whencontaminated wells were replaced with municipal water in 1987. No current exposure pathways are known to exist.

C. Health Outcome Data Evaluation

Health outcome data have been evaluated because past exposure hasoccurred to some compounds that are potential or probablecarcinogens and because the community is concerned about possiblehealth effects associated with using contaminated groundwater. County-level health outcome data were available for review. Theknowledge of the duration of exposure together with site-specifichealth outcome data are necessary to determine possible adversehealth effects from site-related exposures.

The Riggans Mortality Tapes, a database of cancer mortalitymaintained by the EPA and NCI, were reviewed. The databaseincludes virtually all cancer death records for 1950-1979. Thecancer mortality rates are reported by county for each of thethree decades 1950-1959, 1960-1969, and 1970-1979. In addition,the percent change from 1950-59 to 1970-79 is included in thedata. The death certificates data have been obtained from theNational Center for Health Statistics and the Bureau of theCensus. The cause of death is coded by the InternationalClassification of Disease (ICD) codes. The information isprovided for four sex-race groups: white male, white female,nonwhite male, and nonwhite female (U.S. EPA 1987).

The Riggans Mortality Tapes were obtained for ChesterfieldCounty, Virginia, and the United States. Cancer mortality ratesare not elevated for either white or nonwhite women inChesterfield County. However, data from the years 1950 through1979 did indicate elevated cancer mortality rates in white andnonwhite men in Chesterfield County for several types of cancers,associated with the oral cavity and respiratory tract. Forexample, in white men, the death rates for cancers of the oralcavity and tongue; esophagus; and trachea bronchus and lungpleura were consistently higher than the rates for Virginia. Innonwhite men, the death rates for cancers of the oral cavity andtongue; nose, nasal cavities and middle ear sinuses; and tracheabronchus and lung pleura were consistently higher than the ratesfor Virginia. The same type of pattern was observed in thecancer mortality rates for the state of Virginia. Cancermortality rates for cancers associated with the oral cavity andrespiratory tract were elevated for the state, when compared tothe rates of the United States.

ATSDR cannot determine if the elevated cancer mortality rates inmen are related to exposure to DGSC contaminants because site-specific health outcome data are not available for communitiesnear DGSC. Based on medical literature, development of cancersassociated with the oral cavity and respiratory tract have notbeen linked with exposure to the contaminants (VOCs) that weredetected in the water of off-site private wells.

The Surgeon General's Office has determined that the vastmajority of oral cavity and respiratory tract cancer since the1950s is attributable to increased rates of cigarette use. Chewing tobacco and snuff are also hazardous and cause cancer inthe oral cavity and upper gastrointestinal tract (Surgeon GeneralReport 1982, Hoffmann et al 1983, Amdur et al 1991). Althoughthere are elevated cancer mortality rates in men, no data areavailable on smoking and occupational status for communities nearDGSC, and those factors may have contributed to the developmentof cancers observed in Chesterfield County men.

Before 1989, the Virginia Tumor Registry has relied on voluntaryreporting. Mandatory reporting began in 1989, and a report isnow being generated. That report may be useful in a futureinvestigation. At this time, however, the available informationis too limited to provide an adequate analysis of the data. Ifnew information becomes available, those data will be reviewedfor public health implications.

The Virginia Congenital Anomalies Reporting and Education System(VA CARES) was established in 1985, but actually began receivingreports in 1986. VA CARES receives reports on congenitalanomalies in children from birth to two years of age who weredischarged from any Virginia hospital after January 1, 1987. Atthis time, the VA CARES reporting system has data for 1987 only,and for that reason, the available information is too limited toprovide an adequate analysis of the data. When new informationbecomes available, those data may be reviewed for theirsignificance to public health.

D. Community Concerns Evaluation

The primary community health concern expressed by citizens orlocal public health agencies was about the health of people whoused past contaminated private wells for drinking and otherhousehold uses. Other concerns were related to DGSC's managementof the contamination and communication about activities conductedon the installation. This section evaluates the communityconcerns.

  1. Possible health effects associated with using contaminatedgroundwater.

    The private well contamination in the Rayon Parkneighborhood, north and east of DGSC, resulted in pastexposures for residents who used the water for drinking andother household purposes (Figure 4). Contaminants detectedin private well water that exceeded health assessmentcomparison values were the following VOCs: benzene, 1,2-DCA, 1,1-DCE, PCE, 1,1,1-TCA, and TCE. The exact durationof the past exposures is not known; however, exposuresstopped when most of the 21 residences were connected to thepublic water supply in 1987. Possible health effectsassociated with past use of contaminated water with multipleVOCs is unknown, largely because of the lack of datapublished on health effects stemming from chronic exposureto multiple contaminants. However, because of infrequentexposure to low levels of VOCs in those wells, adversehealth effects are not expected.

    Evaluation of the health outcome data from the years 1950through 1979 indicated elevated cancer mortality rates forwhite and nonwhite men in Chesterfield County, but not inwomen. The Surgeon General's Office has determined that thevast majority of oral and respiratory tract cancer since the1950s is attributable to increased rates of cigarette use. Chewing tobacco and snuff are also hazardous and causecancer in the oral cavity and upper gastrointestinal tract(Surgeon General Report 1982, Hoffmann et al 1983, Amdur etal 1991). Since data are not available on smoking andoccupational status for those exposed individuals, ATSDRcannot completely evaluate if those increased rates arerelated to contaminant exposure. However, the medical andscientific literature have not linked exposure to VOCs withdevelopment of cancers associated with the oral cavity andrespiratory tract. Exposures to individual contaminants arediscussed in the Public Health Implications section.

    At least three private wells in the Rayon Park area, inwhich contamination has not been detected are still beingused for drinking water and household uses. When the wellswere tested in 1987 and found to be free of contamination,those property owners elected to continue using their wells. Those three wells, and possibly other private wells in theKingsland Creek area, are still used for drinking water andhousehold activities and are not regularly monitored. Fromrecent sampling conducted in June 1992, it appears thatprivate wells in the Kingsland Creek and Rayon Park area arecurrently free of contamination. A well survey conducted inOctober 1992 indicate that out of 108 survey responses,there are 16 private wells being used for potable purposeswithin a quarter mile off site of DGSC. Residents usingthose wells may be exposed to DGSC contaminants, ifcontaminant plumes are determined to migrate to the north,northeast, or south. Therefore, periodic identification andmonitoring should be conducted, if sampling indicates thatcontaminant migration could potentially occur.

  2. The extent of contamination at the installation and currentmonitoring efforts.

    Remedial Investigations now have been completed for the AcidNeutralization Pit Area, the Fire Training Area, Area 50,the Open Storage Area, and the National Guard Area (Figure3). An expanded site investigation has been completed forthe Fuel Oil Storage Area and Buildings 202, 112, and 68. That report, also containing updated sampling for the RIsites, should be available for public review in mid May of1993. An interim plan for remediation of groundwater eastof the National Guard Area is being prepared and should beavailable for public review in late April of 1993. Thosecompleted documents will become part of the administrativerecord, and results will be placed in a repository forpublic review.

    This public health assessment discusses and evaluates healthconcerns expressed by the community and state and localofficials. This document has been available for a publiccomment period during which anyone interested in theinformation could review it and comment on the contents. Nocomments from the public were received.



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