Methods for Evaluating Temporal Groundwater Quality Data and Results of Decadal-Scale Changes in Chloride, Dissolved Solids, and Nitrate Concentrations in Groundwater in the United States, 19882010 analyzes groundwater quality trends in the United States between 1988 and 2010. Samples were extracted in two sampling events (the first event between 1988 and 2000 and the second event between 2001 and 2010) from 1,235 wells residing in 56 well networks in and measurements taken for dissolved solids, chloride, and nitrate. The comparison of the two sampling events revealed significant increases in dissolved solids, chloride, and nitrate concentrations from the 1988-2000 period to the 2001-2010 period.
