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 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.     

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.     

Preliminary assessment of current radiation doses to the population of Brodokalmak from contamination of the Techa River

Significant quantities of liquid radioactive waste were discharged to the Techa River in the southern Urals region of Russia in the early years of operation of the Mayak PA plant (1948–1951). A collaborative project is underway under contract to the European Commission to consider the radiological impact of radioactive contamination in the Southern Urals. Part of this project involves the calculation of radiation doses currently received by the population of Brodokalmak on the Techa river. The assessment made use of local data on the habits of the population and measurements of radionuclide activity concentrations in food and water. Exposure pathways included in the assessment were ingestion of foods and external exposure to gamma radiation from radionuclides deposited on the banks of the river. A range of doses was calculated for different age groups, firstly, assuming that the restrictions in place are retained and, secondly, assuming that there are no restrictions. These restrictions include bans on drinking river water, fishing and bathing in the river and the prohibition of use of the river and surrounding flood plains by humans and cattle. With restrictions the highest dose estimated was 0.56 mSv y⁻¹ for the most exposed adults and without restrictions this increased to 3.4 mSv y⁻¹.