USGS Study Reports Quality of California Desert Groundwater
Inorganic elements detected at high concentrations in 35% of
region's untreated groundwater Inorganic elements — arsenic,
boron, fluoride and five others — were detected at high
concentrations in 35% of untreated groundwater used for public
water supply in the desert region of Southern California in a
recent study by the U.S. Geological Survey (USGS). In contrast,
human-made organic chemical constituents and nitrate were found
at high concentrations in less than 1% of the desert region’s
aquifers. This study's findings are important, in part, because
elsewhere in California, high concentrations of inorganic
elements generally are found in 10% to 25% of the aquifer system
used for public supply, nitrate in 1% to 8%, and human-made
organic chemical constituents in up to 2%. "High" concentrations
are defined as above the U.S. Environmental Protection Agency's
(EPA) or California Department of Public Health's established
maximum contaminant levels (MCLs)