GROVE CITY, MERCER COUNTY, PENNSYLVANIA
Contamination and Human Exposure (Table 1,2,3)
Vinyl chloride, a known human carcinogen, is present in the groundwater beneath the site. Four four mine void monitoring wells showed VC concentrations from 2 to 5 g/L in a 1995 sampling round (Figure 3). Though the eastward extent of the plume appeared to be characterized by monitoring wells MWV3, MWV4, and MWV6, a series of sampling events in 1993 and 1994 revealed VC at a concentration varying from less than 1 to 16 g/L in one residential well (HW-1) (Figure 3) that is beyond the monitoring well perimeter. That concentration is about an order of magnitude 10 times higher than the concentration in MWV4 some 550 feet closer to the site. Furthermore, the residential well in question is the only well affected by site contaminants based upon EPA's repetitive sampling of seven wells near the landfill.
Occupants of the home have been on public water since the summer of 1994 when Cooper Industries, under pressure from EPA, extended a supply line along Enterprise Road and Diamond Roads (1 and Figure 3). The current occupants moved into the home in 1980. There is no historic information on when this residential well was first contaminated. The PADOH has no information on previous occupants of the home.
Area homes are now connected to the public water supply except for two homes whose wells are clean and continue to be monitored by EPA (oral communication with EPA).
Vinyl Chloride was detected in one residential well at concentrations varying from less than 1 to 16 g/L (1). Two adult residents live in this household. Groundwater usage (i.e. drinking, cooking, showering) can expose residents to VC through inhalation, ingestion, or dermal absorption.
Some people who have breathed VC for several years developed hepatic abnormalities. Greater than expected incidences of angiosarcoma of the liver in workers occupationally exposed to VC were reported. Angiosarcoma of the liver is a very rare type of cancer. Some people who had worked with VC have nerve damage, and others have developed an immune reaction. Some polyvinyl chloride production workers exposed to very high levels of VC also have problems with the blood flow in their hands (3). The lowest levels that cause liver changes, nerve damage, and the immune reaction in humans are not known. However, these levels of occupational exposure to VC are over several magnitudes higher than the levels normally found in the residential settings. Health effects are not expected from inhalation exposure at this site.
No studies were found regarding the health effects on humans through oral exposure. However, animal studies have shown hematological and hepatic effects among animals fed diets containing high concentrations of VC. To evaluate noncancerous effects on humans, ATSDR has developed a chronic oral Minimum Risk Level (MRL) of 0.00002 mg/kg/day based on animal studies that demonstrate changes in the livers of animals orally exposed to VC (3). MRL is an estimate of a daily exposure to a contaminant below which noncancerous, adverse health effects are unlikely to occur. The two residents who used the contaminated well for drinking water are unlikely to ingest enough vinyl chloride to attain the doses at which adverse health effects have been observed in humans or laboratory animals (based on the average concentration level of 8.0 g/L).
EPA has classified VC as a human carcinogen. The U.S. Department of Health and Human Services (DHHS) has determined that VC is a known carcinogen. Likewise, the International Agency for Research on Cancer (IARC) has determined that VC is carcinogenic to humans. EPA is currently reviewing the carcinogenic risk associated with VC. Therefore, neither the Cancer Risk Evaluation Guide (CREG) nor an oral Cancer Slope Factor (CSF) is available for this substance, and the related calculation of the increased risk of cancer health outcomes associated with exposure to VC cannot be made at this time.
In response to community concerns, health outcome data were gathered and reviewed routinely at the the townships or boroughs level. Evaluation of the health outcome data for geographical areas smaller than the township is difficult because the townships or boroughs are the smallest geo-unit, for which the State Center for Health Statistics normally aggregates and reports data.
PADOH reviewed the cancer mortality data (1986-1995) and cancer incidence data (1985-1994) for 23 types of cancer [Appendix] for Pine Township where the site is located. The review of the data did not reveal elevated cancer deaths and cancer incidences in the township except deaths from prostate cancer among men and non-Hodgkin's Lymphomas (NHL) among women compared to deaths in the state of Pennsylvania.
In general, suspected risk factors for prostate cancer include occupational exposure to cadmium and work in rubber manufacturing and farming [4,5]. Substantial epidemiologic evidence suggests that a diet high in fat, particularly animal or saturated fat, increases the risk of prostate cancer . Factors related to sexual activity, including certain viruses, also are suspected risk factors, although evidence for this is relatively weak . It is likely that sex hormones play some role in the development of prostate cancer . In addition, a family history of prostate cancer in a first-degree relative appears to double the risk .
Some studies found that individuals at increased risk of the NHL include those with viral infections such AIDS and patients who are immunosuppressed subsequent to transplantation . Individuals who work in occupations dealing with chemicals and agriculture may also be at increased risk of NHL. Exposure to certain phenoxy herbicides was implicated though the evidence is not conclusive . A number of studies have been conducted concerning plastics manufacturing which involves vinyl chloride. Most studies, however, did not find an increased risk of NHL .
Since no data are available from the death certificate on personal risk factors, residential history, or occupational exposure, the causes of elevated prostate cancer mortality and NHL mortality in Pine township are not known. However, they are not believed to be associated with the site based on known risk factors for these two types of cancer.
There were no site-related contaminants reaching other residents except two residents who experienced vinyl chloride in their water supply. Because the number of people who were exposed to the contaminants was a very small number, no standard statistical analysis methods can conclusively determine if any adverse health effects these people may have experienced, if any, were caused by the site.