First data on technetium-99 content in the ecosystem of the Yenisei River

The content of a long-lived technogenic radionuclide 99 Tc in the Yenisei within the territory of radioactive effluents of the Rosatom mining chemical combine (MCC) has been studied. In 2008–2009 the maximal 99 Tc content in water was registered near the dumping site of the MCC and came to 33 mBq/l. According to analysis of filtered water samples, technetium in the Yenisei water is presented as pertechnetate ion (TcO 4 ). When moving away from the MCC downstream, the 99 Tc content in water is decreased, which is caused both by dilution of waste water and by 99 Tc accumulation by aquatic plants. The 99 Tc content in the biomass of the aquatic plant Potamogeton lucens came to 82 15 Bq/kg, and the concentration factor (CF) to 8200, which is three times more than the maximal values of the CF of 99 Tc by the plants in laboratory conditions (2700).