EFFECTIVENESS OF ELECTRIC-CONDUCTIVITY FOR ESTIMATING DISTRIBUTION COEFFICIENTS OF STRONTIUM AND CESIUM

Distribution coefficient of a radionuclide between soil solid and liqu id phase (K-d) is one of the most important parameters in environmenta l impact assessments on radioactive releases. The value of K-d needs t o be selected carefully considering their dependence on environmental conditions. The environmental information used for K-d determination i s desirably to be highly sensitive and easily obtained in real fields. This study focuses on three environmental Factors measured by simple techniques; temperature, pH, and electric conductivity (EC). The stron tium and cesium K(d)s were measured blv a batch technique under severa l conditions. The K(d)s of both radionuclides were found to be linearl y related to the supernatant ECs on a logarithmic graph; such clear re lationships were not observed for temperature and pH. These results su ggest that the ECs obtained by in situ measurement techniques can be e ffectively applied to accurate, dynamic estimation of strontium and ce sium K(d)s in real fields.