"In this swath of farmland, roughly 250 miles long and encompassing major cities, including Fresno, Bakersfield, and Modesto, the pre-treated water of up to one in 10 public systems has uranium levels that exceed federal and state safety standards, the U.S. Geological Survey has found"
http://ww2.kqed.org/stateofhealth/2015/12/08/uranium-contaminates-water-california-central-valley/
http://ww2.kqed.org/stateofhealth/2015/12/08/uranium-contaminates-water-california-central-valley/