Determination of uranium concentration and speciation in natural granitic groundwater using TRLFS

In this study, the concentration and dominant species of uranium in granitic groundwater sampled from a borehole of an underground research facility were determined using time-resolved laser fluorescence spectroscopy (TRLFS). From the TRLFS measurement and speciation calculation, it was found that uranium mainly exists as Ca2UO2(CO3)3(aq) in all groundwater samples. Uranium concentrations higher than 100 μg/L were found in shallower samples and the cause of this anomaly is discussed. Implications of the results of this work to environmental behavior of uranium in granitic groundwater, is also discussed.