Long-term behaviour of Chernobyl radionuclides in the Dnieper River Basin

The analysis of formation of radioactive contamination of rivers of Belarus, entering the Dnieper basin (Dnieper, Sozh, Iput, Besed, Pripyat), after the accident at the ChNPP is given in the paper. The legitimacies and features of behavior of Chernobyl radionuclides in surface waters and different types of soils on watersheds are detected. Radionuclide concentration dynamics in surface water of Dnieper river basin for period 1987-2006 are present. Transboundary migration of radionuclides through the river networks of Russia, Belarus and Ukraine is estimated. The transboundary migration of 137Cs has decreased markedly with time. On the other hand, the transboundary migration of 90Sr has fluctuated depending on the extent of annual flooding. Long-term behaviour of Chernobyl radionuclides in the difference soil types of Dnieper River watershed is given. Linear velocity of 137Cs, 90Sr for different soil types are found. A forecast of vertical radionuclide migration is made. (author)