Siberian Federal University

Artificial radionuclides, including the transuranic 241Am, have been detected in the bottom sediments (BS) of the Yenisei River in the zone of influence of the Rosatom Mining and Chemical Combine, even after the nuclear reactor was shut down in 2010. This paper presents the first comparative analysis of the potential mobility of artificial radionuclides in Yenisei River sediment core layers, taking into account their formation time and the presence of radioactive microparticles. Radionuclide mobility in the bottom sediments was assessed using two sequential extraction schemes. The high potential mobility of 241Am and 152Eu persists for a long time in all layers of sediment cores. The high binding strength of 137Cs to sediment mineral matter (up to 100 %) remains constant over time. Results of fractionation of bottom sediments with radioactive microparticles showed that 241Am is more mobile compared to 137Cs and 60Co. The long-term persistence of potential mobility of artificial radionuclides in sediments must be taken into account when predicting radionuclide bioavailability in the Yenisei River ecosystem