SAN FRANCISCO (AP) - A new study by the U.S. Geological Survey has found about one-fifth of the raw groundwater in California's public-water supply systems contains high levels of contaminants.
The findings are in a decade-long study using data from 11,000 public-water-supply wells.
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Lead study author Kenneth Belitz said Wednesday the sweeping study was able to assess water supplies for 99 percent of Californians using public water systems.
Belitz says one surprise was the extent to which potentially toxic natural elements like arsenic, uranium and manganese are a problem. The study found several million Californians rely on public water systems whose raw supplies have potentially unsafe levels of those elements.
Kurt Souza of the state Water Resources Control Board says problem public-water systems are required to notify customers and fix the problems by diluting the water or drilling a new well.
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