Influence of physico-chemical forms of radionuclides on their migration in the environment

Physico-chemical forms of 137Cs, 90Sr, in the atmospheric aerosol and deposition, and soil samples after the Chernobyl accident, forest fires and dust storms in the Ukraine and Belarus were investigated. Moreover, some studies of speciations of 239,240Pu, 238Pu in the atmosphere after the Chernobyl accident and concentrations of plutonium in cultivated soil were carried out. These investigations show that radionuclides are in a wide range of forms, depending on sources, transformation peculiarities and radionuclide nature. The most water-soluble 137Cs (up to 77%) was observed in aerosol samples after forest fires in highly contaminated regions and the most insoluble (up to 94%) - also in aerosol samples after a dust storm in the Ukraine. Sequential extraction experiments have shown that the main part of airborne plutonium after the Chernobyl accident (89-87%) was associated with residue. (orig.)