Speciation of plutonium and americium in the soils affected by Kraton-3 accidental underground nuclear explosion in Yakutia (Russia)

In calcareous soils from Yakutia only 0.1 % or less 239 Pu and 241 Am exist in water-soluble form, i.e., the mobility of these radionuclides is relatively low. In the top humus-containing layer (0–4 cm) 239 Pu and 241 Am are distributed uniformly between organic and inorganic soil components. In the bottom soil layer (20–30 cm) the radionuclides are present mainly in inorganic soil components. The estimation of the radionuclide mobility demonstrates that 241 Am is potentially a more mobile element than 239 Pu. In the considered calcareous soils collected from the top layer 239 Pu and 241 Am exist both in humic and fulvic acids (FA). 241 Am is much stronger bound to the group of mobile FA than 239 Pu. In the bottom soil layer 239 Pu and 241 Am have been found mainly in FA.