Electrical conductivity used for evaluation of competing ion effects on radionuclide uptake by plant roots

Although competing ion concentration is one of the sensitive factors affecting radionuclide transfer in a soil-to-crop pathway, continuous measurement of each ion concentration is now difficult in an actual field. In this study, using electrical conductivity (EC) was proposed as an alternative of ion concentration for evaluating the competing effect on uptake of cationic radionuclides (⁵⁴Mn, ⁶⁰Co, ⁶⁵Zn, ⁸⁵Sr, ¹³⁷Cs) by a leafy plant (Brassica campestris). Linear relationships in the logarithmic graph were found between the selective absorption coefficients and the solution ECs. For ¹³⁷Cs, the competing effect was found to be relatively small. Because of its easiness and quickness in measurement, the EC is expected to be effectively applied to prediction of changes in soil-to-plant transfer of selected radionuclides where the soil salinity varies in time and spatial scale. (author)