[Radioactive contamination of aquatic organisms of the Yenisei River in the area affected by the activity of the Mining-and-Chemical Combine].

The study was done to investigate the content of manmade radionuclides in aquatic organisms of the Yenisei River near the Mining-and-Chemical Combine (MCC) and to estimate the exposure dose rates to organisms from various sources. The results of the investigation and calculations suggest that the main source of radioactive contamination of aquatic organisms is the coolant of the third MCC reactor, which is still being released into the Yenisei. Gamma-spectrometric analysis revealed 23 manmade radionuclides in the biomass of aquatic plants. The aquatic animal Phylolimnogammarus viridis and diatoms also contain manmade radionuclides. Among aquatic organisms, the highest dose rate is received by aquatic plants (up to 39 microGy/day). For most aquatic organisms under study, the dose received from the technogenic irradiation is an order of magnitude higher than the dose received from natural irradiation. The water moss (Fontinalis antipyretica) features the highest capacity to accumulate manmade radionuclides; hence, it accumulates the largest technogenic exposure dose among the study aquatic organisms.