New data on potential mobility of artificial radionuclides in bottom sediments of the Yenisei River

The present study shows that after the shutdown of the nuclear reactor at the Mining-and-Chemical Combine (MCC) of Rosatom in 2010, artificial radionuclides (60Co, 137Cs, 152Eu, and 241Am) are still detected in the bottom sediments (BS) of the Yenisei River in the MCC affected area. The paper, for the first time, reports results of the study comparing potential mobility of artificial radionuclides in the surface and lower layers of the Yenisei BS long after the shutdown of the MCC nuclear reactor. The mobility of radionuclides was estimated using the well-known procedure of sequential extraction of BS. A new finding is that potential mobility of 60Co is higher in the lower (older) BS layers compared with the upper ones. Radionuclide 137Cs is strongly bound with mineral solids of BS (approaching 100%) regardless of the time factor. The new data showing that 241Am and 152Eu retain their high potential mobility in the BS over long periods and that 60Co potential mobility increases over time suggest potential bioavailability of these radionuclides in the Yenisei River ecosystem.