2 major US aquifers contaminated by natural uranium released by human pollution

Public Release: 17-Aug-2015
Study: 2 major US aquifers contaminated by natural uranium
Naturally occurring uranium is being mobilized by farm-related pollution
University of Nebraska-Lincoln

Nearly 2 million people throughout the Great Plains and California above aquifer sites contaminated with natural uranium that is mobilized by human-contributed nitrate, according to a study from the University of Nebraska-Lincoln.

Data from roughly 275,000 groundwater samples in the High Plains and Central Valley aquifers show that many Americans live less than two-thirds of a mile from wells that often far exceed the uranium guideline set by the Environmental Protection Agency.

The study reports that 78 percent of the uranium-contaminated sites were linked to the presence of nitrate, a common groundwater contaminant that originates mainly from chemical fertilizers and animal waste. Nitrate mobilizes naturally occurring uranium through a series of bacterial and chemical reactions that oxidize the radioactive mineral, making it soluble in groundwater.

UNL researchers Karrie Weber and Jason Nolan found that the High Plains aquifer contains uranium concentrations up to 89 times the EPA standard and nitrate concentrations up to 189 times greater. The uranium and nitrate levels of the California-based Central Valley aquifer measured up to 180 and 34 times their respective EPA thresholds.

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