How did USGS develop the data sets used to assess VOCs in aquifers?
The study of aquifers is a large component of the National Water-Quality Assessment (NAWQA) Program’s ambient ground-water assessments. Aquifer studies have been completed in nearly every NAWQA Study Unit and have provided a comprehensive picture of the chemical quality of water in locally and regionally important aquifers. In addition, data from comparable studies with a similar design were included to expand the geographic coverage of the assessment. Samples from 3,498 wells in 98 aquifer studies that were collected during 1985-2002 were analyzed for 55 volatile organic compounds (VOCs). These analytical results were used to assess VOCs in aquifers.
