The work is devoted to the study of radioecological processes of redistribution of plutonium alpha-radionuclides (239+240Pu) as the main man-maid dose-forming alpha-radionuclides during the period after Chernobyl NPP accident. 239+240Pu are long-lived radioisotopes, the content of which is increasing in natural ecosystems from incident to incident. Radiotoxicity of these radionuclides is high, and we need science-based approaches of assessment and forecast of radioecological condition of the basins being at risk of a radioactive re-contamination, such as the Black Sea as an inland sea located at region close to developed countries using nuclear technologies. The study was performed with modern advanced techniques, the main of them were radiochemical analysis, alpha-spectrometry and radiotracer technologies. As a result of investigation the radiological regularities of plutonium behavior in the Black Sea ecosystem during the post-Chernobyl period were revealed. Quantitative parameters of plutonium migration in the sea were determined: sedimentation rates at different areas of the sea, the 239+240Pu effective half-lives in surface water, the 239+240Pu radiocapacity factor for bottom sediment, the 239+240Pu fluxes, levels of 239+240Pu in the ecosystem components, and the 239+240Pu accumulation factors for biotic and abiotic components. The features of the biogeochemical behavior of plutonium in the Black Sea ecosystem were identified and the conditions and processes causing them were indicated. The increased ability of the Black Sea surface water to self-purification against 239+240Pu, short residence time of plutonium in surface waters, the relatively high rapid of plutonium accumulation in the bottom sediment due to biogeochemical sedimentation of it, the high concentration ability of silt sediment against 239+240Pu and the type of biogeochemical behavior of plutonium in the Black Sea ecosystem has been observed.
Plutonium concentration distribution in bed load sediment samples along the Romanian sector of the Danube River and the Black Sea coast
