Radon and thoron concentrations in private groundwater wells near uranium mining activity in South Texas

When uranium and radon are detected in groundwater in South Texas, there is often public controversy as to whether the uranium is present naturally, or is rather a consequence of uranium mining activity in the area. In South Texas there are 26 closed and 4 operating uranium mines. The purpose of the study was to conduct an evaluation of the groundwater quality near a uranium in-situ recovery (ISR) mining operation. Parameters evaluated in fifty private wells included 222Rn, fluoride, chloride, sulfate, nitrate, conductivity, dissolve oxygen, temperature and alkalinity. The results showed that 50% of the sampled wells had radon concentrations below 300 pCi/L, 46% had concentrations between 307 and 4000 pCi/L, and 4% had concentrations above the AMCL of 4000 pCi/L. The radon concentrations showed positive correlation with distance from the mining site and negative correlation with the nitrate concentrations. Finally, the results showed that groundwater temperature and sulfate concentrations were significantly greater than in previous studies in Kleberg County.