[Accumulation of radionuclides in food chains of the Yenisei River after the nuclear power plant shutdown at the mining-and-chemical enterprise].

Accumulation of artificial and natural radionuclides in the chains of food webs leading to non-predatory and piscivorous fish of the Yenisei River was investigated during one year before and three years after the shutdown of a nuclear power plant at the Mining-and-Chemical Combine (2009-2012). The activity of artificial radionuclides in the samples of biota ofthe Yenisei River (aquatic moss, gammarids, dace, grayling, pike) was estimated. The concentration of radionuclides with induced activity (51Cr, 54Mn, 58Co, 60Co, 65Zn, 141, 144Ce, 152, 154Eu, 239Np) decreased in the biomass of biota after the shutdown of the nuclear power plant; the concentration of 137Cs did not. Analysis of the accumulation factors (C(F)) allows us to expect the effective accumulation of 137Cs in the terminal level of the food web of the Yenisei River--pike (C(F) = 2.0-9.4), i.e. biomagnifications of radiocesium. Accumulation of artificial, radionuclides in non-predatory fish from gammarids was not effective (C(F) < 1). An effective accumulation of 40K is possible in muscles of non-predatory and piscivorous fish species from food (C(F) = 2:6-3.1 and 1.3-1.4, respectively). C(Fs) of K and 40K were equal in all trophic pairs, but C(Fs) of 40K and 137Cs differed considerably.