Influences of Soil and Plant Types on The Mitigation Rate of Radium-226 in The Cultivated Soils

The effects of fertilizers, irrigation water, and air dust pollution on the long-term accumulation of radionuclides in surface soils have been investigated worldwide. In addition, many factors cause the removal of radionuclides from the soil. The removal rate is difficult to estimate because it is controlled by several parameters such as agricultural practices and soil properties. In this study, the mitigation rate of Ra-226 in the topsoil of agricultural soils in 20 fields in Vietnam was measured. The rate was considered two main processes that rejected radionuclides from the topsoil. Moreover, the soil-to-plant transfer factors (TF) and solid/liquid partition coefficients (Kd) for these soils have been reported. It was found that the obtained values of TF and Kd were wide and depended on the plant and soil types. The new experimental method gives the leaching rate of Ra-226 matching that based on the models, except for the rice paddy soil. For twenty considered soils, the mitigation rates of Ra-226 were from 0.1 to 0.58 Bq kg⁻² y⁻¹. The trend of Ra-226 mitigation correlated with the uptake ability of the plant (TF) and the Ra-226 concentration in pore water (Kd).