A site-specific study on the measurement of sorption coefficients for radionuclides

A study on the potential of geological media from the vicinity of the mining site in Tummalapalle region of Andhra Pradesh in India for retardation of radionuclide migration in groundwater was conducted. The studies included the measurement of sorption coefficients for six radionuclides, uranium, thorium, lead, bismuth, radium and polonium, between two groundwater simulants and two site-specific samples of geological media. Initial parametric studies involving chemical composition, pH, calcium carbonate and organic carbon contents of both geological media and ground water simulants were carried out. Significant differences in sorption coefficients were observed as a result of varying pH, calcium carbonate and presence of trace quantities of organic contents in simulant solutions. For example, uranium has a hundred fold lower distribution coefficient in the case of simulant solution having higher carbonate content. Similarly, in the case of the geological media having higher calcium carbonate and organic carbon contents, higher distribution coefficients were obtained for all radionuclides. Among the six radionuclides studied thorium showed the largest and radium the smallest distribution coefficient values for the soil samples assessed. The site-specific sorption coefficients will be used for contaminant transport study.