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PUBLIC HEALTH ASSESSMENT

FORMER NANSEMOND ORDNANCE DEPOT
SUFFOLK, VIRGINIA


III. DISCUSSION

A. Types of Data Used

The preparation of this report involved the review of site historical documents, correspondence, and numerous reports on previous investigations at the site. Reviewed investigations included ordnance surveys as well as sampling of site soils, groundwater, surface water, sediments, and fish at locations in and around the site. ATSDR also reviewed reports of the removal and remedial activities that have taken place on the site to date.

In addition to site environmental data, ATSDR considered health outcome data available for the population near the site. ATSDR assessed current site conditions during two visits to the site on June 22 and 23, 1999 and on June 26, 2003. During the June 1999 site visit, ATSDR also met with the community to learn what health concerns nearby residents had about the site.

The conclusions reached in this document are based on the data available at this time and are subject to modification, depending on what additional information becomes available as EPA/ACE activities continue at the site.

B. Scope of Public Health Evaluation

In this public health assessment, ATSDR attempts to draw conclusions about public health implications for the site as a whole from the findings for areas that have been investigated to date. Because of the large size of this site, the investigations for both ordnance and chemical contamination have focused on specific areas, such as known disposal areas, where contamination is considered likely. Characterizing the boundaries and cleaning up these areas will address the vast majority of chemical and ordnance hazards. However, it is possible that previously undocumented areas of chemical contamination and/or ordnance items will be discovered in the future. Such a discovery could alter the general conclusions made in this document.

ATSDR's evaluation of past exposures includes the time frame after 1960, when the facility was converted to private use. Assessing historical exposures to former military personnel, who may have had direct occupational exposures as well as indirect environmental exposures, would involve too many uncertainties to allow meaningful conclusions to be drawn.

Several geographical areas on the FNOD site will not be evaluated in this document. The offshore marine area has limited information on which to base an assessment of potential human exposures, and human exposures in this area are expected to be small compared to those in other areas. In addition, the VDOT and HRSD properties have limited access, and the limited information available of these properties does not indicate significantly elevated contaminant levels [16,17]. ATSDR assumes that exposures to workers at these controlled sites are small compared to exposures to people in other areas. Finally, GE is performing cleanup activities at the GE building area. Because the current building occupants are mainly warehouse employees and therefore not extensively exposed to outdoor contaminants, ATSDR assumes that their exposures are small compared to exposures of people in other areas. If data or other information become available indicating that any of these assumptions are invalid, ATSDR will evaluate these areas in an addendum to this document.

Land Tracts at FNOD
Figure 2. Land Tracts at FNOD

C. Chemical Contamination: Summary of Areas Evaluated at FNOD

To organize the vast amount of data available on areas of FNOD, ATSDR broke the site up into four tracts of land on the basis of the ownership of the land, as shown in Figure 2. These are the Dominion Lands, the GE Lands, the TCC Property, and the VDOT/HRSD Property. As discussed previously, the VDOT/HRSD property will not be evaluated in this PHA because exposures of workers on these limited-access sites are not as great as exposures of people elsewhere on the site. These properties will be evaluated at a later date if new information indicates such an evaluation is warranted.

  1. Dominion Lands
  2. The Dominion Lands run along the southwest border of the FNOD site. Substantial parts of the onsite area have been the subject of chemical and ordnance investigation and cleanup activities [1,18-28]. The southeast part of the Dominion Lands contains a number of deep brick vaults of unknown function that may pose physical hazards. About 135 acres of the land on the site and additional adjacent property have been developed by Dominion Lands into an industrial/ commercial park called Bridgeway Commerce Park [29]. Other parcels of the land might be developed in the future. A summary of the main areas on Dominion Lands for which chemical contaminant data are available follows.

    Horseshoe Pond Disposal Area
    The Horseshoe Pond Disposal Area is located on the northwest end of the Dominion Lands property. The area is bordered on the northwest by the Nansemond River, on the southwest by a tidal marsh, on the southeast by a heavily wooded area, and on the northeast by the GE plant building and parking area [30]. Metal debris and other solid waste have been observed along the pond, and it appears that land around the pond has been excavated, possibly to cover debris in the area. The pond itself is approximately 1-2 acres in size and has no inlets or discharge points. Groundwater discharge is the major source of water for the pond. A remedial investigation was performed on this area, and supplemental investigations are occurring [30,31].

    Impregnite Kit Area (a.k.a. XXCC3 Landfill)
    This source area was a former disposal area for impregnite kits located on the Dominion Lands property about 1,000 feet from the Nansemond River. Impregnite kits, used during World War II to increase the chemical resistance of military issue chemical suits, contained XXCC3, a fine, white, powder, and a black waxy material or honey-like syrup. These materials and several other hazardous substances were found at the site prior to cleanup. Removal of the kits and the surrounding contaminated soil was conducted in December 1998 and January 1999. Geophysical investigations were conducted in June 1999 and August 2002 to confirm that no other disposal areas were present [32]. Results of confirmation soil sampling collected starting in July 1999 were used to show that no threat to human health remained from soils, and the soils in the area were deleted from the NPL in March 2003 [33,34]. Groundwater underneath the XXCC3 area is still being characterized as part of the remedial investigation.

  3. GE Lands
  4. The GE Lands run along the northeast border of the Dominion Lands, and includes a large building that is a former television manufacturing facility, the shoreline along the Nansemond River, the GE pond, which drains through a culvert to the Nansemond River, and the Main Burning Ground and Steam-out Pond, two areas associated with former military decommissioning activities. The building itself will not be included in this evaluation; however, other areas on the GE lands have been the subject of chemical and ordnance investigations and cleanup activities. A summary of the main areas on GE Lands for which chemical contaminant data were evaluated follows.

    GE Pond
    The GE pond is located next to the GE building. A drainage ditch formerly ran from the Main Burning Ground / Steam-out Pond to the GE Pond, suggesting that contaminants might have been deposited there. The GE Pond drains through an underground culvert to the Nansemond River Beachfront Area. Sediments in the GE Pond and at the culvert's outfall were sampled in 1997 and 2001 [35].

    Main Burning Ground/ Steam-out Pond
    The Main Burning Ground/ Steam-out Pond is located south of Park Drive on property owned by GE. The area is a likely location of inspection, decommissioning, and disposal of unserviceable ammunition by defusing or burning during World Wars I and II. TNT from shells handled at the site was recovered at the Steam-out Pond [30]. A remedial investigation was performed on this area, and supplemental investigations are occurring [30,31].

    Nansemond River Beachfront
    This area is a 353-foot stretch of beach located behind the GE plant on TCC property. ACE found non-hazardous metal slag on the beach, and visible large debris was removed in September 2001. Small pieces of slag material continued to surface under rocks and concrete debris on the beach as a result of wave action. Consequently, one foot of soil from underneath the rocks was removed and disposed of offsite. Erosion control measures are being evaluated [36-38]. Slag material and unexploded ordnance have continued to surface on the beachfront area.

  5. TCC Property
  6. The balance of the FNOD site, about 520 acres, is currently owned by TCC. A relatively small portion of the property is used for campus activities, and lands lying mostly to the east side of the property are overgrown and unused, although several buildings and other structures from former military operations are still present. Many areas on the TCC Property have been the subject of chemical and ordnance investigations and cleanup activities. A summary of the main areas on TCC Property for which chemical contaminant data were evaluated follows.

    TNT Burial Site
    The TNT Burial Site consists of a 2- to 3-acre plot on College Drive where disposed ordnance and a large quantity of bulk crystalline TNT were discovered in 1987. The plot is bordered on the north by a college athletic field and on the west by College Drive, with unused land to the south and east. The area has been the subject of numerous soil and groundwater sampling events, surface ordnance sweeps, and soil and ordnance removals. Clean fill soils have been placed in excavated areas [3,7,39- 41]. The latest round of soil and groundwater sampling at this area was completed in spring 2003 [42]. Ordnance removals continue at this area; TNT, both crystalline and in small burlap fuse bags, continues to be encountered.

    James River Beachfront Landfill
    The James River Beachfront Landfill was apparently used as a general disposal site during the World War II era. The waste buried at the area has been shown to include scrap metal, construction and building debris, and some World War I and World War II ordnance material (including projectiles, metal boxes, caisson parts, and fuses). The area is undeveloped and subject to continued erosion by the James River, which washed away some cover soils and disposed materials in the past. Environmental sampling and ordnance surveys have been conducted at the disposal area [18,19,43-47]. ATSDR previously reviewed pre-1996 soil sample data and concluded that for infrequent exposure, significant adverse health effects were not likely [14]. A removal of debris and inert ordnance was conducted in the summer of 2001, and a stone wall was installed to protect the shoreline from further erosion. In this document, ATSDR will review post-removal confirmation soil samples, considering potential future development scenarios [36,37].

    Track K Dump/Tire Pile
    The Track K Dump/Tire Pile is located west of South Road on the TCC campus. This source area is a 7 to 10-acre unused wooded area containing a 250×100 foot area of discarded tires and a 12×12 foot area of discarded paint cans. ACE removed the tires and paint cans in June 2001. Confirmation soil sampling showed no elevated levels of tire- or paint can-related contaminants in soils at the site. No further remedial action is anticipated for this site [37,48].

    TCC Lake
    TCC Lake has been used for recreational activities, including fishing. Students and faculty of Frederick College lived next to the lake in the 1960s. Several former bunker locations nearby have been subjected to sampling activities. Non-intrusive ordnance inspections and surveys have been initiated on the lake and along its shoreline [18-20,44,49]. Fish and sediment from TCC Lake were sampled in August 2000 [50,51].

    J-Area Lake
    J-Area Lake has been used for recreational activities, including fishing. Several former bunkers were located nearby, and adjacent ground may have been used for burning ordnance materials [19,20]. Fish and sediment from J-Area Lake were sampled in August 2000 [52].

    TCC Former Water Supply Wells
    Until early 1997, TCC had used several wells for potable water for students, faculty, and staff. Water samples from these wells have been taken on several occasions. In about 1993, in response to concerns about the potential for contamination, TCC made bottled water available. The wells were abandoned when the college connected to the City of Suffolk municipal water system [1,7,18,39,53,54].

    In 1995, in response to a citizen's petition that raised concerns about the site, ATSDR evaluated a set of 1992 water quality data for the TCC supply wells. ATSDR concluded that contaminant levels detected in a number of samples were not at levels that would represent a public health hazard [13].

    Streeter Creek
    Streeter Creek lies at the east end of the site and discharges northward into the James River. Several magazines and possible disposal areas lie close to the creek or its tributaries. Several water and sediment samples have been taken, in and around the main creek channel [18,55].

  7. Offsite Area Evaluated–Respass Beach Potable Water Wells
  8. In addition to the land tracts described above, some offsite areas have the potential to be affected by former uses of the site, in particular the Respass Beach community. This community consists of a group of about 80 homes located east of the mouth of Streeter Creek. The community relies on groundwater wells for its potable water supply. Several wells have been tested [56,57], and results are evaluated in this document.

As additional information becomes available through ongoing and future investigations, ATSDR will address health issues in other locations, as appropriate. Also, conclusions for areas addressed herein will be reevaluated, if warranted by new information.

D. Evaluation Process

The process by which ATSDR evaluates the possible health impact of contaminants is summarized here and described in more detail in Appendix A. The first step involves screening the available data for contaminants of concern (COCs). ATSDR uses comparison values (CVs) to determine which chemicals to examine more closely. CVs are concentrations of chemicals in the environment (water, soil, or sediment) below which no adverse human health effects are expected to occur. Exceeding a CV does not mean that health effects will occur; rather, it indicates that more evaluation is needed. ATSDR also considers sampling location and data quality; exposure probability, frequency, and duration; and community health concerns in determining which chemicals to evaluate further.

If a chemical contaminant is selected for further evaluation, the next step is to identify which chemicals and exposure situations could be a health hazard. Child and adult exposure doses are calculated for COCs in site media (e.g., soil, groundwater, surface water, sediment, or fish), using exposure assumptions as described in Appendix B. Exposure doses are the estimated amounts of a contaminant that people come in contact with under specified exposure situations. These exposure doses are compared to appropriate health guidelines for that chemical. Health guideline values are considered safe doses–that is, health effects are unlikely below this level. If the exposure dose for a chemical is greater than the health guideline, then the exposure dose is compared to known health effect levels identified in ATSDR's toxicological profiles. If the COC is a carcinogen, the cancer risk is also estimated. These comparisons are the basis for stating whether the exposure is a health hazard.

E. Contaminant Screening, Exposure Analysis, and Toxicological Evaluation

The following sections describe the various ways people could come into contact with contaminants at the site. Each of these ways is called an exposure pathway. ATSDR sorted the large amount of contaminant data available by media (soil, sediment, surface water, groundwater, or fish) and by the land tract in which the sampling was performed. Next, each media in each land tract was screened for COCs. COCs were further evaluated by estimating exposure doses based on assumed uses of the different land tracts detailed below in Table 1. For past exposures, ATSDR used data from before any cleanup activities took place. Present exposure and future evaluations considered post-removal confirmatory sampling.

Table 1.

Assumed Land Uses at FNOD
Land Tract Distant Past Use (1960-1967) Present and Recent
Past Use
(1967-2003)
Potential Future Use Potential Exposure Media
Dominion Lands Light industrial use, trespassing, occasional recreation Light industrial use, occasional recreation Residential use, recreation, fishing, light industrial use Soil, sediments, surface water
GE Lands Light industrial use, trespassing, occasional recreation Light industrial use, trespassing, occasional recreation Light industrial use, trespassing, occasional recreation Soil, sediments, surface water
TCC Property Residential use near TCC Lake, more frequent recreation, fishing, swimming Day students & faculty, occasional recreation, fishing Residential use, recreation, fishing, light industrial Soil, sediments, surface water, groundwater (pre-1997), fish
VDOT/HR
SD Properties
Unknown (Not Evaluated) Limited access (Not Evaluated) Limited access (Not Evaluated) Not Evaluated

1. Dominion Lands

a) Soil and Sediment

Tables 2 and 3 list the chemicals in the Dominion Lands area that were detected in soiland sediment at least once above substance-specific soil or sediment CVs.

Table 2.

Surface Soil Contaminants Present Above Comparison Values–Dominion Lands
Contaminant Maximum concentration in soil, parts per million (ppm) Comparison Value (CV) in ppm CV Source (defined in Appendix A)
Impregnite Kit Area (Before Removal):
Carbon tetrachloride 21* 5 CREG
Dieldrin 1.0†† 3 / 0.04 cEMEG / CREG
Phosphorus 239** 1 RMEG
Impregnite Kit Area (Post-Removal):
Arsenic 5 20 / 0.5 cEMEG / CREG
Horseshoe Pond Area:
Antimony 62 20 RMEG
Arsenic 40 20 / 0.5 cEMEG / CREG
Iron 340,000 23,000 R9 PRG
Lead 599 400 SSL
Thallium 16 5.2 R9 PRG
Polycyclic Aromatic Hydrocarbon Toxicity Equivalence Quotient 0.8 0.1 CREG
Bridgeway Commerce Park and Other Dominion Lands Areas:
Arsenic 15** 20 / 0.5 cEMEG / CREG
Dieldrin 0.08‡‡ 3 / 0.04 cEMEG / CREG
Phosphorus 1240** 1 RMEG
Sources: *[1]; ††[20]; [34]; [31]; **[22]; ‡‡[21].


Table 3.

Sediment Contaminants Present Above Comparison Values–Dominion Lands
Contaminant Maximum concentration in sediment, parts per million (ppm) Comparison Value (CV) in ppm§ CV Source (defined in Appendix A)
Horseshoe Pond Area:
Arsenic 40* 200 / 5 cEMEG / CREG
Polycyclic Aromatic Hydrocarbon Toxicity Equivalence Quotient 1.3 1 CREG
§ Sediment CVs calculated as ten times the soil CV.
Sources: *[31]; [24]

These chemicals were then evaluated using assumptions of how people could have been or could be exposed at this site. For past exposures, ATSDR assumed that adults or older children might be on Dominion Lands four times a week throughout the year. ATSDR assumed that each day they were on site, adults accidentally ingested 100 milligrams (mg) of soil or 10 mg of sediment, and children accidentally ingested 200 mg of soil or 20 mg of sediment (see Appendix A for further exposure assumption details). Initial screening was performed with the maximum soil or sediment value. The resulting estimated exposure doses for all compounds except iron, lead, and phosphorus in soil were lower than health guideline values, indicating that no health effects are expected. Past and present exposures to iron, lead, and phosphorus in soil were retained for further consideration and are evaluated below.

ATSDR was requested to evaluate potential future uses of the Dominion Lands, including residential use. For future exposures, the same calculation was performed using the maximum soil value detected and assuming potential future residential use (i.e., small children could access the soil throughout the year). The only estimated exposure doses higher than health guideline values were those for antimony, arsenic, iron, lead, phosphorus, and thallium. Evaluation of these potential future exposures follows.

Further Evaluation of Soil and Sediment–Dominion Lands

Iron
The estimated past exposure of older children to the maximum concentration of iron found in soil is 1 mg/kg/day, higher than the health guideline of 0.3 mg/kg/day. However, no health effects are expected from this exposure. The Institute of Medicine has established tolerable upper intake levels for iron ranging from 40 mg/day for infants and children to 45 mg/day for teenagers and adults [59]. The estimated exposure dose would correspond to a daily intake of about 36 mg/day, within the recommended intake. In addition, the estimated dose conservatively overestimated actual exposure to iron, because the maximum concentration was used instead of the average, iron may be less available in soil than in toxicological studies, and exposure to soil will probably be less frequent than assumed due to climate and weather factors. Therefore, no health effects due to past and present exposure to iron in soil at the Dominion Lands are expected. If the exposure were to increase as a result of conversion of the Dominion Lands to residential use, the estimated maximum iron dose would rise to 7 mg/kg/day, or about 70 mg/day for small children. This dose would be unlikely to result in severe toxic effects for an acute exposure, and long-term exposure at this dose is unlikely because exposure would be to an average rather than the maximum concentration. No health effects would be expected from residential exposures to iron in soil at the Dominion Lands.

Lead
Exposure to lead can cause a wide range of effects [60]. However, the lack of a clear threshold for health effects and the need to consider multi-media routes of exposure have made determining toxicological effect levels for lead difficult. The level of lead in blood is a good measure of recent exposure to lead and also correlates well with health effects. Children are especially sensitive to lead, and many of its effects are observed at lower concentrations in children than in adults. Levels of 10 micrograms per deciliter (µg/dL) and less in children's blood have been associated with small decreases in IQ and slightly impaired hearing and growth. The maximum concentration of lead detected in the Dominion Lands was 599 mg/kg (or part per million (ppm)). For the past exposure of older children and adults assumed above, this level of lead in soil would not be expected to raise blood levels enough to result in adverse health effects.

If the Dominion Lands are developed for residential use in the future, small children might be exposed to lead in soil. Epidemiological studies have determined soil slope factors that predict blood lead levels to increase from between 0.0007 and 0.0068 µg/dL for each ppm increase in soil lead level [60]. This wide range resulted from the presence of different sources of lead, exposure conditions, and exposed populations. The highest slope factor of 0.0068 µg/dL/ppm indicates that the maximum lead concentration measured in soil (599 ppm) would be expected to increase blood lead levels by 4.1 µg/dL. The health effects associated with such an increase would depend partly on the existing body burden of lead. The actual blood lead level would be much lower, because children would be exposed to an average rather than the maximum lead concentration and because weather and grass cover would decrease the percentage of time children would be able to contact the soil.

Phosphorus
Phosphorus is a component of several compounds commonly found in the environment, but it does not occur by itself (as an element) naturally. In the soil sampling at Dominion Lands, the phosphorus is listed as total phosphorus, which includes phosphorus compounds and 3 forms of elemental phosphorus (red, black, and white phosphorus). White phosphorus is the form usually associated with munitions and is the most toxic. White phosphorus at high concentrations poses a fire and/or explosive hazard, but because it is so reactive, it does not remain in soil unless it is coated with a protective oxide layer or it is in deep soils where no oxygen is present. Even assuming that the level measured in the soil was mostly white phosphorus, the exposure doses estimated for past exposures of adults and older children would be a fraction of the dose that caused no toxic effects in animal studies, called the no-observed-adverse-effect level (NOAEL) [61]. No adverse health effects would be expected from this exposure. If future development results in children accessing the maximum concentration in a residential setting, the estimated dose would be similar to the NOAEL. However, the actual dose that a child would receive would be significantly lower because exposure would be to an average rather than to the maximum concentration, the percentage of phosphorus present in the most toxic form (white) would be a small percentage of the total, and weather conditions would likely preclude daily contact with soil. No adverse health effects would be expected from this exposure.

Antimony
No health effects are expected from exposure to antimony in soil at the Dominion Lands. Exposure to the maximum concentration of antimony was only slightly above the health guideline value for potential future residential exposures to small children. The actual dose a child might get would be lower because exposure would be to an average concentration rather than to the maximum. Moreover, antimony would not be as easily absorbed from soil as from the aqueous solutions used in toxicological studies [62].

Arsenic
No health effects are expected from exposure to arsenic in soil at the Dominion Lands. Exposure to the maximum concentration of arsenic would be only slightly above the health guideline value for potential future residential exposures to small children. The child residential dose is equal to the dose observed in human epidemiological studies that did not cause any health effects [63]. The actual dose a child might get would be even lower because exposure would be to an average rather than to a maximum concentration. Moreover, arsenic would not be as easily absorbed from soil as from the aqueous solutions that toxicological effect levels are based on. Arsenic is known to cause cancer. However, the estimated increase in the risk of cancer from a lifetime of exposure to arsenic in soil at the Dominion Lands is so low as to be negligible.

Thallium
No health effects are expected from exposure to thallium in soil at the Dominion Lands. Exposure even to the maximum concentration of thallium is only slightly above the health guideline value for potential future residential exposures to small children. The actual dose a child might get would be lower because exposure would be to an average rather than to the maximum concentration and because thallium would not be as easily absorbed from soil as from the aqueous solutions used in toxicological studies [64].

b) Groundwater

Table 4 lists the chemicals that were detected at least once above substance-specific drinking water CVs in shallow groundwater in the Dominion Lands area. The monitoring wells were placed in the unconfined Columbia aquifer. (No chemicals were detected in surface water above drinking water CVs.) Groundwater at the Dominion Lands has never been used for drinking water, so that the past groundwater exposure pathway for this area is incomplete and therefore will not be evaluated further.

Table 4.

Groundwater Contaminants Present Above Drinking Water Comparison Values - Dominion Lands
Contaminant Maximum concentration in groundwater, micrograms per liter (µg/L) Drinking Water Comparison Value (CV) in µg/L CV Source (defined in Appendix A)
  Horseshoe Pond Area Impregnite Kit Area Other Dominion Lands    
Aluminum 97,100* 113,000* 77,200* 20,000 iEMEG
Arsenic 194* 214* 141* 3 / 0.2 cEMEG / CREG
Diethylhexyl phthalate (DEHP) 6 Not analyzed Not analyzed 3 CREG
Beryllium 23.9* Less than CV Less than CV 20 cEMEG
Cadmium 8.5* Less than CV Less than CV 2 cEMEG
Chromium 420* 193* 365* 30 RMEG (hexavalent)
Cobalt 261* Less than CV Less than CV 100 iEMEG
Iron 284,000* 165,000* 103,000* 11,000 R9 PRG
Lead 79.3* 73.3* 54.7* 15 AL
Manganese 8,910* 939* Less than CV 500 RMEG
Nickel 281* Less than CV Less than CV 200 RMEG
Vanadium 477* 317* 370* 30 iEMEG
Sources: *[24]; [31].

ATSDR was requested to evaluate the Dominion Lands groundwater for potential future drinking water use. Using exposure assumptions described in Appendix A, ATSDR estimated exposure doses for the COCs listed in Table 4. The estimates assumed that adults would drink 2 liters of water per day (L/day) and that children would drink 1 L/day. The estimated exposure dose for diethylhexyl phthalate was lower than the health guideline values and not expected to significantly increase the risk of cancer, so that no health effects are expected from exposure to this contaminant in groundwater. An evaluation of potential future exposure to the other COCs in groundwater at the Dominion Lands follows.

Further Evaluation of Groundwater–Dominion Lands

Aluminum
Both child and adult doses (10 mg/kg/day and 3 mg/kg/day, respectively) from drinking the maximum level of aluminum in drinking water would be higher than the intermediate MRL of 2 mg/kg/day. The child dose is about one-sixth the intermediate-duration NOAEL for neurotoxicity found in a mouse study, 62 mg/kg/day [65]. Exposure to aluminum would be unlikely to result in health effects.

Arsenic
The child dose from drinking the maximum level of arsenic in drinking water (0.02 mg/kg/day) would be higher than the LOAEL shown to cause skin changes in human epidemiologic studies, 0.014 mg/kg/day [63]. The adult dose of 0.006 mg/kg/day would be about half the LOAEL. A lifetime of drinking this level of arsenic in water would result in a moderate to high increased risk of developing cancer.

Beryllium
Drinking water containing the maximum level of beryllium in Dominion Lands groundwater would be unlikely to lead to health effects. Estimated adult and child exposure doses were only slightly above the minimal risk level and were still hundreds of times lower than the dose estimated to result in an increase in the incidence of small intestine lesions in a dog study [66].

Cadmium
Drinking water containing the maximum level of cadmium in Dominion Lands groundwater would be unlikely to lead to health effects. Estimated child and adult exposure doses (0.0009 mg/kg/day and 0.00024 mg/kg/day, respectively) were lower than the NOAEL of 0.0021 mg/kg/day from human studies. Animal data indicate that cadmium is a probable human carcinogen [67]. However, there is no oral cancer slope factor for cadmium, so that it is not possible to evaluate carcinogenic risk.

Chromium
Most of the available data did not specify the type of chromium detected; when the type was not specified, ATSDR conservatively assumed the reported concentrations to be chromium (VI), which is more toxic than chromium (III). If adults or children were to drink water containing the highest concentration of chromium measured in the Dominion Lands groundwater, they would receive doses of chromium estimated at 0.01 mg/kg/day for adults and 0.04 mg/kg/day for children. While these doses are less than the chronic LOAEL for humans of 0.57 mg/kg/day, some sensitive individuals might still experience gastrointestinal effects. In addition, less serious effects, such as enhancement of dermatitis, have been reported after acute exposure to doses as low as 0.036 mg/kg/day [68].

Cobalt
The estimated cobalt dose for a child drinking water containing the maximum amount of cobalt was 0.03 mg/kg/day, several times lower than the lowest observed adverse effect level (LOAEL) of 1 mg/kg/day, which caused a reversible increase in the number of red blood cells in adult male volunteers [69]. The estimated adult dose is lower than the MRL. No health effects would be expected to result from exposure to cobalt at this level in drinking water.

Iron
The calculated child dose from drinking water with the highest iron concentration is 30 mg/kg/day, high enough to result in acute toxic effects, including nausea and vomiting [58]. The adult dose (8 mg/kg/day) would probably not result in acute effects. However, the daily intake resulting from this exposure is ten times the tolerable upper limit, and long-term exposure to this level could cause clinical effects such as accumulation of iron in the liver [59,58]. Water containing such a high iron concentration would have an unpleasant taste, reducing the likelihood that it would be used for drinking.

Lead
As described previously, levels of lead in children's blood of 10 micrograms per deciliter (µg/dL), and perhaps lower, have been associated with small decreases in IQ and slightly impaired hearing and growth. A slope factor for the increase in blood lead concentration per increase in water lead concentration for infants has been calculated as 0.04 µg/dL blood per part per billion (ppb) lead for water lead levels above 15 ppb [60]. The corresponding slope factor for school children was found to be 0.03 µg/dL per ppb. At the maximum concentration of 79 ppb lead measured in the Dominion Lands groundwater, increases in blood lead concentrations of 3.2 µg/dL and 2.4 µg/dL are predicted for infants and school children, respectively. The health effects associated with such increases would depend partly on the existing body burden of lead.

Manganese
Epidemiologic studies suggest an association between ingesting water containing elevated concentrations of manganese and the development of neurological symptoms. However, each of the studies had uncertainty regarding the exposure level or whether the effects were solely attributable to manganese, so that no NOAEL, LOAEL, or minimal risk level could be identified [70]. Studies with rats have shown a LOAEL for neurological changes of 14 mg/kg/day, an order of magnitude higher than the estimated child dose of 0.9 mg/kg/day and also much higher than the adult dose of 0.3 mg/kg/day. However, humans appear to be more sensitive to manganese than animals [70]. Therefore, the estimated future child and adult manganese dose for this pathway could cause health effects.

Nickel
The estimated dose for a child drinking water containing the maximum concentration of nickel is 0.03 mg/kg/day, only slightly more than EPA's reference dose (RfD) of 0.02 mg/kg/day. Oral exposure to nickel has caused skin reactions in sensitive people at doses as low as 0.009 mg/kg/day, but in general, reactions are considered unlikely for doses less than the RfD [71].

Vanadium
The maximum concentration of vanadium in Dominion Lands groundwater would not be expected to result in health effects if the water were used for drinking. The estimated child and adult doses (0.05 mg/kg/day and 0.01 mg/kg/day, respectively) are several times lower than the NOAEL for renal effects found in an intermediate duration study in rats. Another study in which adult humans were given doses of vanadium 50 times higher than the doses estimated here showed no changes in liver or renal enzymes nor hematological abnormalities over 45 to 68 days [72].

Summary–Potential Future Use of Dominion Lands Groundwater for Drinking

The available data indicate that without treatment, the shallow groundwater in the Dominion Lands area is not suitable for drinking purposes. The levels of several contaminants, especially arsenic, chromium, iron, lead, and manganese, are high enough to cause adverse health effects in children and/or adults. Because the sampled groundwater was from the shallow, unconfined aquifer, it is unlikely to be used for drinking water. Deeper groundwater in this area was not sampled and therefore is not evaluated in this report.

2. GE Lands

a) Soil and Sediment

Tables 5 and 6 list the chemicals in the GE Lands that were detected in soil and sediment at least once above substance-specific soil or sediment CVs. For past exposures, ATSDR assumed that adults or older children might be on GE Lands 4 times a week throughout the year. ATSDR also assumed that each day they were on site, adults accidentally ingested 100 milligrams (mg) of soil or 10 mg of sediment, and children accidentally ingested 200 mg of soil or 20 mg of sediment (see Appendix A for further exposure assumption details). Initial screening was performed with the maximum soil or sediment value. The resulting estimated exposure doses for all soil and sediment COCs were lower than health guideline values, indicating that no health effects are expected.

Table 5.

Surface Soil Contaminants Present Above Comparison Values-GE Lands
Contaminant Maximum concentration in soil, parts per million (ppm) Comparison Value in ppm CV Source (defined in Appendix A)
Arsenic 6.5* 20 / 0.5 cEMEG / CREG
Dieldrin 0.17* 3 / 0.04 cEMEG / CREG
Polycyclic Aromatic Hydrocarbon Toxicity Equivalence Quotient 1.0* 0.1 CREG
* Source: [31]


Table 6.

Sediment Contaminants Present Above Comparison Values-GE Lands
Contaminant Maximum concentration in sediment, parts per million (ppm) Comparison Value (CV) in ppm§ CV Source (defined in Appendix A)
Arsenic 39.5* 200 / 5 cEMEG / CREG
§ Sediment CV calculated as ten times the soil CV.
* Source: [31]

ATSDR was requested to evaluate future uses of the property. For the GE Lands, potential future uses are likely to be similar to present uses; therefore, the conclusions reached for past and present use will apply in the future as long as the use remains light industrial with only occasional trespassing or recreational use. No health effects from soil or sediment exposure are expected for such future uses.

b) Groundwater

Table 7 lists the chemicals detected in groundwater at least once above substance-specific drinking water CVs in the GE Lands area. (No chemicals were detected in surface water above drinking water CVs.) Specifically, the groundwater data in Table 7 come from the main burning ground area. In the past, workers in the GE building obtained drinking water from a nearby groundwater well. The data in Table 7 are not representative of this drinking water source, and therefore an evaluation of the past drinking water usage at the GE building cannot be performed in this PHA.

Table 7.

Groundwater Contaminants Present Above Drinking Water Comparison Values–GE Lands
Contaminant Maximum concentration in groundwater, micrograms per liter (µg/L) Drinking Water Comparison Value (CV) in µg/L CV Source (defined in Appendix A)
Arsenic 13* 3 / 0.2 cEMEG / CREG
Diethylhexyl phthalate 6 3 CREG
Dieldrin 0.0078* 0.002 CREG
Source: [31]

ATSDR was requested to evaluate the GE Lands groundwater for potential future drinking water use. Using residential exposure assumptions described in Appendix A, ATSDR estimated exposure doses for the COCs listed in Table 7. Estimated exposure doses of diethylhexyl phthalate and dieldrin were lower than health guideline values, so that no health effects are expected from exposure to these contaminants in groundwater. An evaluation of potential future exposure to arsenic in groundwater at the GE Lands follows.

Further Evaluation of Groundwater–GE Lands

Arsenic
The exposure doses for children and adults derived from the assuming residential consumption of the maximum concentration of arsenic in GE Lands groundwater were higher than the MRL of 0.0003 mg/kg/day. However, according to EPA, the GE Lands will not be developed for residential use in the future. Therefore, ATSDR modified the exposure assumption to that of adult workers who drank water with the maximum concentration of arsenic for 250 days a year for up to 20 years. ATSDR also assumed that only 75% of a worker's daily water intake, or 1.5 liters per day, would be from groundwater at the site. On the basis of these assumptions, the estimated dose was lower than the MRL, so that chronic noncancer health effects are unlikely. Arsenic is a carcinogen, but the estimated increase in the risk of cancer from drinking the water as assumed is within EPA's acceptable range [63].


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