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California's Drought Worsens Uranium Pollution In Valley Wells

Feb 3, 2015

File photo
Credit John Chacon / CA Dept of Water Resources

California’s drought isn't just causing wells to go dry, it's also contributing to a long running water pollution problem.

A new study by the U.S. Geological Survey looked at over 100 private domestic drinking water wells in the San Joaquin Valley. It found that around 1 in 4 had uranium levels above those considered safe by the EPA. Most of the wells were on the east side of the valley, which is home to sediment from the Sierra Nevada which naturally contains uranium.

USGS hydrologist Bryant Jurgens says while the uranium isn’t new, it’s now contaminating more and more groundwater.

Jurgens: “It’s really kind of a process that we sort of induced on the system. We’ve changed the chemistry of water that normally would recharge the aquifer.”

Jurgens says when farmers irrigate their crops or homeowners water their lawns, they set off a chemical chain reaction that makes water more acidic as it percolates down into the soil, which eventually dissolves minerals and releases uranium into the aquifer.

And California’s drought is making the problem worse.

Jurgens: “We’re pumping the aquifer a lot more and that’s going to drive this uranium water that’s generally shallow to deeper parts of the system, so it’s going to occupy a larger and larger portion of the aquifer.”

Jurgens says the issue is a bigger concern for private residential wells, which are generally shallow, and don’t have the ability to blend with other water sources like many municipal projects can.

While uranium is radioactive, it’s also a heavy metal which can accumulate in the kidneys and cause serious health problems.