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 a ffecting radionuclide transfer in a soil-to-crop pathway, continuous m easurement of each ion concentration is now difficult in an actual fie ld. In this study, using electrical conductivity (EC) was proposed as an alternative of ion concentration for evaluating the competing effec t on uptake of cationic radionuclides (Mn-54, Co-60, Zn-65, Sr-85, Cs- 137) by a leafy plant (Brassica campestris). Linear relationships in t he logarithmic graph were found between the selective absorption coeff icients and the solution ECs. For Cs-137, the competing effect was fou nd to be relatively small. Because of its easiness and quickness in me asurement, the EC is expected to be effectively applied to prediction of changes in soil-to-plant transfer of selected radionuclides where t he soil salinity varies in time and spatial scale.