Pesticides and volatile organic compounds in shallow urban groundwater of the United States

The widespread use of pesticides and volatile organic compounds (VOCs) over the past half century has led to their detection in many hydrologic systems in the United States. However, few systematic investigations of occurrence have been carried out over multistate regions using a consistent study design. Nine urban studies of shallow groundwater have been conducted to date as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Pesticide compounds were detected in 48.6% of the 208 urban wells sampled. Sixteen different pesticide compounds were detected in samples from these wells. Prometon was by far the most frequently detected pesticide compound, being found in 8 of the 9 urban studies. VOCs were detected in 53.4% of the 208 urban wells sampled, with 36 different VOC compounds being found. Measured VOC concentrations exceeded current U.S. Environmental Protection Agency drinking water regulations in 19 wells. Methyl tert-butyl ether (MTBE), a common fuel oxygenate, was the most frequently detected VOC for this study.