The transfer of uranium from sediment to water along Jucar River, Spain

The effect of sediment size, pH, temperature and conductivity on the transfer of uranium from sediment to water has been studied. The uranium concentration and the 234U/238U, 235U/238U activity ratios were measured in water, sediments and suspended matter sampled from Jucar River, using low level alpha-spectrometry. Distribution factors were obtained from these measurements. A more detailed sampling was done in the neighbourhood of the Cofrentes Nuclear Plant (Valencia, Spain). Total uranium activity, 234U/238U activity ratio and distribution factors for 234U and 238U were found to vary with pH. Leaching and dilution, which depend on pH and salinity, are the probable mechanisms for these changes. (author)