ACCOUNTING FOR CONCENTRATED AND AREA SOURCES OF IMIDACLOPRID IN GROUNDWATER, SUFFOLK COUNTY, LONG ISLAND, NY

摘要

The groundwater in Suffolk County, New York provides drinking water for over one millionpeople and is especially sensitive to contamination from the land surface. The area's suburbanand agricultural landscapes are among New York's heaviest users of pesticides. Thus SuffolkCounty has become the critical test case for New York's regulation of pesticides in groundwater.Imidacloprid —-1-(6-chloro-3-pyridinylmethyl)-N-nitroimidazolidin-2-ylidenamine—- is asystemic chloronicotinyl insecticide and neonicotinoid-class insect neurotoxin and is the mostwidely used insecticide in the world. It treats a broad variety of crops and ornamentals and ispermitted for use on most of Suffolk County's land area. Imidacloprid provides a useful casestudy of New York's and Suffolk County's ground water protection approach. Existing literaturecontains numerous examples of contamination of surface waters from uses of imidacloprid inagricultural fields. (US EPA, 2008; Starner & Goh, 2012; Main, et al., 2014; Nemeth-Konda,2002; Lamers, et al., 2011; Bortoluzzi, et al., 2007). The impact of most agricultural productsused in greenhouses -- a very important part of Suffolk County's agriculture -- has not beenthoroughly considered, and represents a potential source of groundwater pollution (Kreuger, etal., 2010). This study evaluates results from about 2000 samples from pesticide-targetedmonitoring wells in Suffolk County's from 2001 -2010. These data were integrated withapplications of root zone and vadose zone transport and fate models, covering both field uses andconcentrated uses such as greenhouses with fugitive emissions..Data from monitor wells show that, in general, imidacloprid concentrations stay far below theState's 50 µg/L standard for unspecified organics in drinking water (NYS DEC, Bureau of PestManagement, 2015). The few exceptions are outlying cases where spills or misuse may haveoccurred. The root zone and vadose zone models help to account for why widespreadimidacloprid use does not translate into widespread ground water contamination in SuffolkCounty. The deep water table and imidacloprid's degradation rate in the near surface soil arewell-documented factors. Degradation within the deeper vadose zone, and unquantifiedemission pathways from greenhouses are the least understood potential contributors togroundwater quality.