Radiochemical procedures for speciation of actinides in the environment: methodology and data obtained in contaminated regions of Russia by radionuclides

The migration ability of radionuclides in biosphere mainly depends on their occurrence forms, which are ultimately responsible for the potential hazards to human beings. In the paper, the radiochemical methods for actinides speciation in aqueous and solid environmental samples are discussed. They include membrane fractionation, ion exchange, solvent extraction, coprecipitation, adsorption, electrophoresis for water samples and selective leaching, organic substances fractionation, liquid and membrane extraction, partition chromatography, membrane retention with water-soluble polymers, etc. for solid samples. These techniques were used during radio-monitoring of zones near Production Association 'Mayak' and Krasnoyarsk Mining-Chemical Plant. The data on oxidation states of plutonium in aqueous samples and in soil and its leached solution was obtained. The organic matter fractionating of soils allowed to explain experimental values of migration coefficients of 137Cs, 90Sr, 239Pu, and 241Am. This data was used for long-term prediction of radionuclides migration behaviour in zone under investigation. (authors)