Preliminary evaluations of regional ground-water quality in relation to land use

Preliminary results from New York, New Jersey, Connecticut, Florida, Nebraska, and Colorado indicate that regional ground-water quality has been affected by human activities. The frequencies of detection of volatile organic compounds and some trace elements were larger in ground water underlying urban or industrial areas in comparison to undeveloped areas. Ground water in agricultural areas generally had larger concentrations of nitrate and an increased frequency of detection of pesticides. Effects of human activities on water quality increased as the intensity of urbanization or irrigation increased. Ground-water pumpage, waste-water discharges into a stream that is hydraulically connected to an alluvial aquifer, and consumptive use of ground water affected the ground-water quality in one study area to a greater extent than land-use practices.