Concentration, soil-to-plant transfer factor and soil-soil solution distribution coefficient of selenium in the surface environment

Of the major radioactive selenium isotopes, Se-79, a beta emitter with a half-life of about 1.1 million years, is of special interest because it is one of the most important radionuclides for the long-term dose assessment of radioactive waste disposal. This radionuclide can reach human beings through several transfer paths in the environment. To predict Se-79 behavior from the environment to human beings, it would be useful to obtain the following information: stable Se concentration in environmental samples; soil-soil solution distribution coefficient (Kd); and soil-to-plant transfer factor (TF). In the present study, stable Se concentrations in river water, soil and crop samples collected in Japan, Kds and TFs were obtained. The results showed that geometric mean (GM) concentrations of river water, soil and crops were 0.057 ug/L (range: <D.L.-1.17 ug/L), 0.43 mg/kg (range: 0.068-1.56 mg/kg-dry), and 0.015 mg/kg-dry (range: