Soil as a geochemical bar­rier for radium and uranium propagation in terrestrial ecosystems of Belarus
Parameters for evaluating the barrier properties of soils during uranium and radium redistributing in terrestrial ecosys­tems have been determined. The reserves of migratory active and potentially mobile <sup>238</sup>U and <sup>226</sup>Ra species in the soils of the regions outside the zone contaminated with transuranic elements of Chernobyl fallout, have been estimated. Radionuclides associating with interstitial soil waters have been identified as the migratory uranium and radium species, and radionuclides reversibly bounding with solid phase of soil complex and extractable from soils by 1 M solution of ammonium acetate - as potentially mobile forms of these species. The <sup>238</sup>U and <sup>226</sup>Ra distribution coefficients between solid substrate and interstitial water of soils have been evaluated. These coefficients characterize the soil sorption capacity for uranium and radium. The data obtained can be used for parameterization of redistribution forecasting models for uranium and radium in soils and con­tamination levels of natural waters and biological community, both for background radionuclide content and in the case of additional anthropogenic contamination of the environment.