Distribution of radionuclides among the main components of Lake Chervyanoe in the Eastern Ural Radioactive Trace

Radioecological conditions have been estimated in Lake Chervyanoe located on the central axis of the Eastern Ural Radioactive Trace (EURT) about 100–110 km northeast of the Mayak Production Association. Data on the ⁹⁰Sr and ¹³⁷Cs contents in the main components of the lake, the distribution of these radionuclides over the profile of bottom sediments, and their amounts in the lake are presented. The experimental data have been used to construct mathematical models for estimating changes in the radionuclide concentrations and amounts in the water and bottom sediments of the lake over a long period after the nuclear accident, as well as the tritium content of the lake water in different periods of time.     

Radioecological Studies on the Plankton of the Cooling Water Reservoir of the Beloyarsk Nuclear Power Plant

In the zone of heated water discharge and at the control site of the Beloyarsk Reservoir, the phytoplankton was characterized by dominance of blue-green, green, and pyrrophyte algae, and the zooplankton, by the prevalence of crustaceans over rotifers. The study sites differed in the species and quantitative composition of the dominant complex, but the total abundance and biomass of the phytoplankton in the heated zone and the control site did not differ significantly. In Teplyi Bay, the zooplankton was inhibited, which was manifested in the decrease of its abundance and biomass by four and seven times, respectively, in comparison with the control. Radionuclide concentrations in the plankton of the cooling reservoir in the period between 1986 and 1988 were determined. It was found that radionuclide concentration in the plankton is higher in the zone of heated water discharge than beyond it.     

Radioecological investigation of the Techa-Iset' river system

Data on the current radioecological situation in the Techa-Iset' river system, which was contaminated by radioactive wastes from the Mayak Production Association in the 1940s and 1950s, are discussed. Mathematical models are presented that describe the decrease in the contamination of water, bottom sediments, hydrobionts, and floodplain soils with an increase in the distance from the discharge site. The amounts of⁹⁰Sr,⁹⁹Tc,¹³⁷Cs, and transuranium elements in the main components of the ecosystem are estimated.     

Changes in plankton abundance, biomass, and chemical composition under the influence of the cooling system of the Beloyarsk Nuclear Power Plant

The abundance and biomass of phytoplankton and zooplankton proved to noticeably decrease after the water passed through the cooling system of the Beloyarsk Nuclear Power Plant: the phytoplankton perished by 38% (65 metric tons per day), and the zooplankton, by 55% (6 t/day). In the period between 1985 and 1991, the concentration of⁶⁰Co in the plankton of water intake and discharge canals varied from 120 to 1400 Bq/kg dry weight, and that of¹³⁷Cs, from 150 to 1040 Bq/kg dry weight, which is commensurable with the content of radionuclides in the plants and grounds of the Beloyarsk reservoir. In 1985, it was noted that the plankton passing through the cooling system of the nuclear power plant became enriched with Ca, Fe, Mg, Mn, Co, Cs, Cu, Mo, Ni, Pb, Si, Sn, Ti, V, and W.     

The role of planktonic organisms in accumulation and transfer of radioactive contaminants in the cooling reservoir of a nuclear power plant

The results of long-term studies (1985–2006) on the state of planktonic communities and their capacity for accumulation of radioactive contaminants in the cooling reservoir of the Beloyarsk Nuclear Power Plant (BNPP) have been summarized. The changes in the population density and biomass of planktonic organisms have been estimated in different water areas of the Beloyarsk Reservoir. The levels of radionuclide accumulation by phyto- and zooplankton in the reservoir and technological channels of the BNPP have been determined. The contributions of two nuclear power enterprises (the BNPP and the Institute of Reactor Materials) to the accumulation of radionuclides by planktonic organisms have been evaluated. The rates of radionuclide accumulation by phyto- and zooplankton have been estimated and compared with those of other components of the aquatic biocenosis.     

Species Composition and Ecological Characteristic of Algae from the Cooling Reservoir of the Beloyarsk Nuclear Power Plant

The results of long-term studies on phytoplankton in the cooling reservoir of the Beloyarsk Nuclear Power Plant (the Middle Urals) are reviewed. Altogether, 199 taxa of the species and subspecies rank have been recorded, including 144 taxa described in this water body for the first time. The algoflora of the reservoir consists mainly of widespread and eurybiontic freshwater species.     

Some characteristics of plutonium distribution in the atmospheric air and plants in the zone surrounding the Mayak Production Association

The results of long-term studies on plutonium distribution in the atmospheric air and plants in the area surrounding the Mayak Production Association in the years 1976–1995 are summarized. Data are presented on the changes in plutonium concentration in the air overtime at some points located in the survey zone and the impact zone of the industrial enterprise as compared to those in the control region. In addition, data on the changes in air plutonium concentration depending on the season and direction of wind are presented; the ratios between plutonium concentrations in the air and the fallout are analyzed.Translated from Ekologiya, No. 1, 2005, pp. 20–25.Original Russian Text Copyright © 2005 by Chudin, Shcherbakova, Maslovskii, Kocheva, Iovlev, Denisenko, Demin, Mamin, Chebotina.     

Patterns of the accumulation of chemical elements in the plankton of a fresh water body

For the first time, comparative data are presented on the distribution of 70 chemical elements occurring in the Beloyarsk Reservoir between the water and the plant and animal components of the plankton (phyto- and zooplankton). All these elements are ranked into groups according to the values of accumulation coefficient (AC) for phytoplankton and zooplankton. For the sum of all chemical elements, a significant positive correlation has been revealed between their content in the water and in the plankton. It has been shown that elements with even atomic numbers and concentrations in the plankton below 7 ??g/g dry weight are accumulated by the plankton in significantly larger amounts than such elements with odd atomic numbers. This fact confirms the classic concept developed by A.P. Vinogradov that the prevalence of chemical elements in the biosphere depends on their position in the periodic system.     

Radionuclides in the Ecosystem of Lake Tygish in the Zone of the Eastern Ural Radioactive Trace

The radioecological situation in Lake Tygish is described. The lake is situated on the central axis of the Eastern Ural Radioactive Trace (EURT), which was formed after the nuclear accident in the Southern Urals in 1957. The distributions of ⁹⁰Sr and ¹³⁷Cs among the main components of the water body and the results of the measurement of tritium concentration in the water are presented. Mathematical models are described that have made it possible to estimate changes in the concentrations of radionuclides and their amounts accumulated in the water and bottom sediments of the lake during the long period after the accident and to predict the development of the radioecological situation in the lake until 2057. Based on the mathematical models, more accurate data on the initial ecological situation in the lake in the year of the accident have been obtained.