Fingerprint Analysis for Distinguishing Between Potential Groundwater Contamination and Background near a Uranium Mining Site

Uranium has been mined in the Texas Coastal Plain Uranium District since the late 1950s, first by open pit and underground mining and later predominantly by the in-situ recovery (ISR) method, which has become the primary uranium mining method.  In South Texas, as of August 2012, there were two ISR uranium mines in production, two in standby, one in restoration, and one partially permitted and licensed.  There were also an additional 23 closed ISR uranium mines and more than 16 licensed uranium exploration sites. As ISR mining has expanded in the region during recent years, public concern about potential contamination of groundwater resources has also increased.  Consequently, improved monitoring of groundwater quality near existing and closed ISR uranium mining areas is needed to better distinguish between naturally occurring uranium and possible impacts from ISR operations. In this study, water samples from private wells in an area near an ISR uranium mine were collected and analyzed, not only to determine the quality of the groundwater, but also to establish fingerprint differences between groundwater with naturally occurring uranium and its decay products and the pregnant lixiviant extracted from groundwater at the mining site.  The “Fingerprint Analysis of Leachate Contaminants” (FALCON) methodology, developed by the U.S. Environmental Protection Agency, was adapted to develop a unique multi-parameter fingerprint for the ISR lixiviant as a means of distinguishing between potential ISR mining contamination due to excursions and natural background conditions.