Survey of Uranium and Radon in Private Wells in Kleberg County Texas

The presence of uranium (U) and its daughter radon (Rn) in groundwater is a concern in Kleberg County, Texas. Two cities have U concentrations in their public water supplies that are above the EPA’s drinking water standard and are planning to implement reverse osmosis or ion exchange treatment in the near future. In addition, private wells in the region have also been found to have uranium concentrations above EPA’s drinking water standard. This has created public controversy as to whether the uranium is present naturally, or is rather a consequence of uranium mining activity in the area. The purpose of this research project is survey U and Rn concentrations in groundwater from private wells in Kleberg County.  The survey will serve three objectives: (1) to protect public health by assessing concentrations of U and Rn in drinking water; (2) to compare existing concentrations in wells that were previously surveyed during a study conducted by the USGS in the late 1970s and characterize any trends; and (3) to develop hydrogeochemical forensic methods to assess whether or not U present in well samples is a result of anthropogenic activity. Towards meeting these objectives, an ICP-MS method has been developed for U and numerous other elements and a scintillation counter method is being developed for Rn. A preliminary survey of 17 private wells in Kleberg County has shown that 14 (82%) had uranium concentrations greater than 7 ppb, and 3 (18%) had uranium concentrations above the EPA drinking water standard of 30 ppb, including one with a concentration of 161 ppb. We are currently investigating the potential for quantifying U(238):Rn(222) ratios to distinguish between dissolved U at near-equilibrium with mineralized U and dissolved U that could potentially have been transported away from mineralized zones as a result of mining activity.