The Radioecological Situation in Terrestrial and Aquatic Ecosystems in the Area of the Scientific Research Institute of Nuclear Reactors Enterprise

The article analyzes the features of the radioecological situation in the zone of possible influence of the State Scientific Center “Scientific Research Institute of Atomic Reactors” (SSC NIIAR, Dimitrovgrad, Ulyanovsk oblast). Field studies were conducted according to the methods recommended for conducting radioecological monitoring. Measurements of the specific activity of natural and manmade radionuclides were carried out on a Multirad scintillation γ-ray spectrometer (Russia) with a 63 × 63-mm NaI(Tl) scintillation detector in threefold repetition. It is shown that at present the radioecological situation in the forests in the territory under consideration is satisfactory: the power of the equivalent absorbed dose of γ radiation, the density of soil pollution and the levels of specific activity of 137Cs in biota do not exceed the normative indicators, with the exception of fungi, the specific activity of which is close to the maximum normative –2500 Bq kg–1. In the Cheremshan Bay of the Volga River, the volume activity of 137Cs in the surface and bottom waters does not exceed the standard (11 Bq L–1); however, significant amounts of technogenic radionuclides such as 137Cs, 134Cs, and 60Co were found in the bottom sediments. In forest and aquatic ecosystems, “critical components” can be distinguished, which are characterized by an increased storage capacity in relation to manmade radionuclides. In forest ecosystems, this is the litter of gray typical forest soil and the dark humus horizon of the urban quasi-ecosystem, and the components of the biota are higher fungi. In aquatic ecosystems, there are bottom sediments.