OLEAN WELL FIELD
OLEAN, CATTARAUGUS COUNTY, NEW YORK
To evaluate the potential health risks from contaminants of concern associated with the Olean Well Field site, the NYS DOH has assessed the risks for cancer and noncancer health effects. The health effects are related to contaminant concentrations, exposure pathway, exposure frequency and duration. For additional information on how the NYS DOH determined and qualified health risks applicable to this consultation refer to Appendix B.
Some residents within the contaminant plume have been and continue to be exposed to contaminated drinking water. The CCHD and the NYS DOH periodically collect samples from private wells located within and around the contaminant plume. The most recent sampling was in September 1995. Three of the wells continue to be contaminated with the site-related contaminant trichloroethene at levels above its NYS DOH's drinking water standard of 5 mcg/L. The results for these wells show trichloroethene at 190 mcg/L, 95 mcg/L and 23 mcg/L, respectively. Samples collected from these wells in the past contained trichloroethene at 1,300 mcg/L (1986), 690 mcg/L (1984) and 61 mcg/L (1981), respectively. Prior to 1981, it is not known how long or at what concentrations people were exposed to this contaminant. Therefore, residents may have been exposed to this contaminant in drinking water for a period of about 10 to 15 years, but possibly longer. Homeowners whose wells were contaminated above the standard were sent letters explaining their well data and the potential health effects of exposure to site-related contaminants, with a recommendation that they connect to the public water system.
Trichloroethene causes cancer in laboratory animals exposed to high levels over their lifetimes (ATSDR, 1995). Chemicals that cause cancer in laboratory animals may also increase the risk of cancer in humans who are exposed to lower levels over long periods of time. Whether or not trichloroethene causes cancer in humans is not known. Based on the results of animal studies and limited sampling of private drinking water wells, these wells continue to be contaminated at levels which upon chronic exposure could pose a low increased risk of developing cancer. Any increased cancer risk is indeterminate for exposures prior to 1981 because no data on levels of contaminants are available.
Trichloroethene can also cause noncarcinogenic toxic effects, primarily to the liver, kidneys and nervous system (ATSDR, 1995). Chemicals that cause effects in humans and/or animals after high levels of exposure may also pose a risk to humans who are exposed to lower levels over long periods of time. Although the risks of noncarcinogenic effects from exposures to the levels of trichloroethene detected in the drinking water are not completely understood, the existing data suggest that they would be low for individuals exposed to this contaminant at a level of 190 mcg/L and minimal at levels of 23 to 95 mcg/L.
The NYS DOH also was concerned that residents living above the groundwater contaminant plume could be exposed to contaminants via migration of soil gas. Consequently, the NYS DOH requested that the US EPA sample soil gas around select homes. Soil gas was sampled in March and October of 1994. Site-related contaminants were present at low levels in some soil gas samples. The USEPA used the data to model whether contaminants in the groundwater could be affecting the indoor air of homes above the plume, and concluded that soil gas did not present an unacceptable risk to residents in the selected homes (USEPA 1994, 1995). However, due to uncertainties in some assumptions used in the model, the NYS DOH decided that indoor air of homes should be sampled to give the most accurate representation of indoor air quality. The NYS DOH sampled the indoor air of select homes in February 1996. No discernible impact on indoor air from groundwater contamination was found since the primary contaminant in groundwater, trichloroethene, was not detected.