Pesticides and Degradation Products Detected in Ground Water
Thursday, July 3rd, 2008(Beyond Pesticides, July 3, 2008) The results of a U.S. Geological Survey (USGS) study  investigating the occurrence of selected pesticides and their degradation products in groundwater shows that these chemicals can persist for years, depending upon the chemical structure of the compounds and the environmental conditions. The study, funded by the USGS National Water-Quality Assessment (NAWQA) Program and published in the May-June issue of Journal of Environmental Quality, specifically examines several of the factors that can influence the likelihood of pesticides and their degradation products being detected in shallow ground water, including oxidation-reduction (redox) conditions and ground water residence times, at four study sites across the United States. Numerous studies over the past four decades have established that pesticides, which are typically applied at the land surface, can move downward through the unsaturated zone to reach the water table at detectable concentrations. The downward movement of pesticide degradation products, formed in situ, can also contribute to the contamination of ground water.The study reveals that the pesticides and degradation products detected most frequently in shallow ground water samples from all four areas are predominantly from two classes of herbicides””triazines and chloroacetanilides. None of the insecticides or fungicides examined are detected […]
