We are surveying groundwater wells in several upstate NY counties for the presence of pesticide residues.

The NY Department of Environmental Conservation (DEC) and others have expressed an interest in a survey of representative areas in upstate New York to determine the occurrence and extent of pesticide contamination of groundwater by sampling rural water systems (domestic and farm), small municipalities and suburban areas. Of particular interest at present are “worst case” areas where significant pesticide use (agricultural and otherwise) coincides with shallow aquifers, presenting elevated risk of contamination in contrast to areas with low pesticide use and/or less vulnerable water resources. The results of this survey would contribute to an assessment (by DEC and others) of the human exposure risk from pesticides in groundwater in the upstate area, which has historically been given little attention.

The first year of work was a pilot-scale program focused on Cortland County, where the Cortland County Soil & Water Conservation District (CCSWCD) cooperated. Sampling on 40 wells detected atrazine (a common and relatively mobile herbicide) found traces in half of the tested wells, but at levels too low to quantitate and far below the drinking water standard. A GIS-based groundwater risk assessment model was developed to guide selection of greatest risk areas for future sampling. Sampling was completed in Schenectady County in 2006 and Orange county in 2007; sampling in Cayuga county is underway in early 2008.

The survey project in Cortland County has already proven to be a useful testing ground. The fact that the wells tested – deemed to be elevated relative risk due to their proximity to pesticide use and the aquifer characteristics – have shown no significant pesticide residues is reassuring, and can be used as presumptive evidence that contamination is unlikely elsewhere in the county. We will continue to sample wells in vulnerable locations in the upstate counties deemed to be at a greater relative risk for groundwater contamination.

New York State Department of Environmental Conservation