RESTON, Va., May 25 (UPI) — Scientists say more than 20 percent of untreated water samples from 932 U.S. public wells contain at least one contaminant of possible health concern.
The U.S. Geological Survey study focused on water collected from public wells before treatment. Officials said about 105 million people receive their drinking water from one of the 140,000 public water systems across the United States that rely on groundwater pumped from public wells.
“By focusing primarily on source-water quality, and by testing for many contaminants that are not regulated in drinking water, this study complements the extensive monitoring of public water systems that is routinely conducted for regulatory and compliance purposes by federal, state and local drinking-water programs,” said Matthew Larsen, USGS associate director for water. “Findings assist water utility managers and regulators in making decisions about future monitoring needs and drinking-water issues.”
The study showed naturally occurring contaminants, such as radon and arsenic, accounted for about three-quarters of contaminant concentrations greater than human-health benchmarks in untreated source water, the USGS said. Man-made contaminants were also found, including herbicides, insecticides, solvents and gasoline chemicals.
“Detections of contaminants do not necessarily indicate a concern for human health because USGS analytical methods can detect many contaminants at concentrations that are 100-fold to 1,000-fold lower than human-health benchmarks,” said lead scientist Patricia Toccalino.
More information is available at http://water.usgs.gov/nawqa/studies/public_wells/.
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