Survey of selected organic compounds in aquifers of New York State excluding Long Island

Samples from 56 wells at 49 sites in New York State, excluding Long Island, were analyzed by gas chromatography/mass spectrometry for the presence of organic compounds designated ' priority pollutants ' by the U.S. Environmental Protection Agency. Most samples were taken from public-supply wells tapping shallow, permeable aquifers, the most susceptible to contamination. Analytical sensitivity reported by the laboratory for most compounds was less than 1 microgram per liter, but contamination during collection, shipping, or laboratory processing required that concentrations be about 10 micrograms per liter before the presence of a compound could be confirmed. Only a small percentage of wells sampled in this study was found to be contaminated. Where contamination is present, it probably results from point sources such as landfills or dumps rather than from general sources such as atmospheric deposition or proximity to urban centers. Two sites, Brewster in Putnam County and Olean in Cattaraugus County, showed clear evidence of contamination. Two other sites, Corning in Steuben County and Fulton in Oswego County, showed evidence of possible contamination. (USGS)