The current state of hydrochemical indicators of Lake Kenon– the cooling reservoir of the TPP

A characteristic is given of the current hydrochemical state of the water of Lake Kenon, which is used as a reservoir - a cooler for the Chita TPP. For over 50-years of operation of the station located on its shore, under the conditions of anthropogenic impact, there has been a sharp change in the chemical type of the lakeʼs water. Currently, the predominant anion is the sulfate ion. Above the MPC standard for water of water bodies of fishery significance are the content of magnesium and sulfates and the trace elements: fluorine, vanadium, strontium, molybdenum, copper, tungsten. The concentrations of boron, lithium, bromine are relatively increased, in some samples - iron, manganese, aluminum and barium.

The effect of heating water on the quantitative parameters of the zoobenthos of the Lukomlskaya GRES cooling reservoir

The changes abundance zoobenthos at the heated zone and non-heated zone on the different depths in summer and autumn was studying in this article. In the heated zone, the abundance was 1.5‒2 times higher than in the non-heated zone in summer and autumn. The basis of the number zoobenthos was oligochaete-chironomid complex. Number distributions zoobenthos was similar to the heated zone and non-heated zone in the summer and autumn.

Ihtiofauna lacului refrigerеnt Cuciurgan în anul 2020

The relevance of the paper lies in the fact that in previous investigations of the ichthyofauna of Cuciurgan cooling reservoir, the main emphasis was placed on economically valuable species. However, a number of invasive fish species have been less investigated, despite occupying, and currently occupying, dominant positions in the structure of the ichthyocenosis of this aquatic ecosystem. The aim of the paper is to research and update data on the diversity, structure and functional status of the ichthyofauna of the Cuciurgan cooling reservoir in conditions of increased anthropogenic and bioinvasive impact. The invasive species Pseudorasbora parva was first identified in the resevoir ecosystem.

Taxonomic structure of the zoobenthos of the Lukoml GRES cooling reservoir

The species composition of zoobenthos in the heated and non-heated zones of the cooling lake Lukoml State District Power Station was studied. 80 taxa of bottom animals have been registered, and two new species of chironomid larvae have been identified. The bottom fauna includes a protected relict species of Pallaseopsis qudrispinosa, which is preserved in the conditions of warming.it is listed in the Red book of Belarus and the alien species – freshwater shrimp Macrobrachium nipponense. The high taxonomic diversity indicates that the Lukoml State District Power Station operation has little impact on the bottom community throughout the lake’s water area. However, species richness is reduced locally by half in the zone of influence of heated water discharge, especially in summer. Under the influence of heating, the taxonomic structure and spatial distribution at different depths change.

Assessment of radiation state of marine environment in the Leningrad NPP area according to long-term monitoring data (1973–2019)

The aim of the study was to conduct a radioecological assessment of the Leningrad NPP marine cooling reservoir – Koporye Bay of the Gulf of Finland. According to the international basic safety standards, accepted at the IAEA General Conference, this issue is of particular relevance due to the need to justify protection from technogenic radiation exposure both to humans and the environment. The assessment was based on the long-term radioecological monitoring data (1973–2019) within the Leningrad NPP observation area: radionuclides concentration in seawater, bottom sediments, and hydrobionts. The reference levels of radionuclides content in seawater and bottom sediments were used as indicators of the radiation state of the marine environment; their calculation procedure is defined in the Recommendations R 52.18.852-2016 and R 52.18.873-2018, issued by the Federal Service for Hydrometeorology and Environmental Monitoring (the Ministry of Natural Resources and Environment of the Russian Federation). These recommendations, developed by RPA “Typhoon” specialists, contain a methodology for assessing the radioecological state of the marine environment by the level of radionuclides activity, based on the principles, ensuring the maintenance of favorable environment, safety of marine hydrobionts, and radiation protection of humans. In the presence of various radionuclides in the marine environment, the sum of technogenic radionuclide activity ratios in seawater (bottom sediments) to the corresponding reference levels shall be below 1. According to monitoring data in the early period of NPP operation (1973–1985), a wide spectrum of technogenic radionuclides was observed in the marine ecosystem components. Along with 137Cs, significant contributors to the contamination of seawater and bottom sediments were 54Mn and 60Co. In contrast to reference levels for 137Cs, reference levels for 54Mn and 60Co in seawater are determined by an environmental criterion, not a radiation-hygienic one. The presence of technogenic radionuclides in algae was registered at distances, exceeding 10 km from the NPP. Biogenic transfer of corrosion radionuclides (54Mn, 60Co, and 65Zn) by fish into rivers, flowing into the Koporye Bay, was noted. The Chernobyl disaster led to a noticeable increase in the pollution of the Koporye Bay with technogenic radionuclides. In May – December 1986, the sum of technogenic radionuclide activity ratios in seawater to the reference levels exceeded the pre-accidental level by 100 times, and in bottom sediments – by 30 times. In 1986, 137Cs and 134Cs were the main contributors to the marine ecosystem radioactive contamination. Currently, the technogenic radioactivity of seawater and bottom sediments of the Koporye Bay is mainly determined by 137Cs; its level is relatively constant, which indicates the stability of the radioecological situation in the Leningrad NPP marine cooling reservoir.

Long-Term Dynamics of Trophic State Indicators in Phytoplankton of the Cooling Reservoir of a Nuclear Power Plant

The dynamics of long-term indicators of trophicity in the cooling pond of a nuclear power plant in Ukraine was analyzed by phytoplankton biomass and bioindicators of trophicity. Greater species richness correlated with the number of species-indicators of greater trophicity. During the contourization processes caused by the introduction of filter-feeding mollusks and changes in the operating mode of the nuclear power plant, there was a decrease in the abundance of phytoplankton and trophic state. During decontourization, there was a sequential “return” of previously eliminated taxa and the restoration of the number of indicator species.

Results of fisheries research of the Shaturskaya group of lakes

Based on the results of comprehensive fisheries research, a brief description of the ecosystem of the lake of the Shaturskaya group operated in the mode of the cooling reservoir of the Shaturskaya GRES is given. The features of the thermal regime of the Shatursky lakes in the zone of the circulating flow of cooled waters are considered. A brief description of the species composition and quantitative indicators of the development of phytoplankton, zooplankton and macrozoobenthos communities is given. The structure of fish catches in the lakes depending on the fishing gear used is considered according to the data of accounting surveys with set nets and fry drag. The process of formation of the ichthyofauna of Shatursky lakes, characteristic of natural and man-made ecosystems of reservoirs-coolers of energy facilities, is shown. The occurrence of native and invasive fish species in catches is described, and the mechanism of seasonal migration of fish depending on the temperature and oxygen regimes of the Shatursky lakes is considered.

Creating a mathematical model of the impact of radiation-hazardous objects on the environment during a fire.

On the basis of the new data on the assessment of the removal from fires from stocks in the combustible material and the speed of weak grassroots fires spread, the wind rose in the Chernobyl Exclusion Zone and the capabilities of the HotSpot software package, there has been developed a mathematical model of real-time assessment of the consequences of accidents that may occur in the areas of radiation-hazardous objects during fires. The proposed model was verified on the basis of comparison with the data obtained during a large-scale fire in the Chernobyl Exclusion Zone in April 2020, and the maps of the Chernobyl Exclusion Zone’s air and soil contamination with 137Cs and 90Sr were made. Using the proposed mathematical model, there has been carried out the analysis of the degree of danger that may create radiation-hazardous objects in case of fire directly on the territory of their location. In the paper, there are also considered the examples of the sanitation point (SP) «Rudnia-Veresnia», SP «Rozsokha» and the «Point of vehicle washing near the ChNPP cooling reservoir» in comparison with the current contamination of air and soil around these facilities with radionuclides. The results of the conducted analysis have been used to make a conclusion about the insignificant impact on the environment of the Chernobyl Exclusion Zone compared to the current level of air pollution and the surface of its territory. Estimates of radiation exposure from SP «Rudnia-Veresnia», SP «Rozsokha» and the «Point of vehicle washing near the ChNPP cooling reservoir» to the environment have been obtained with the help of a simplified mathematical model. These data have a significant correlation with the actual data obtained in April 2020 (during a large-scale fire in the Chernobyl Exclusion Zone) in the areas of location of the points of the automated system of radiation condition control, and places of work, temporary and permanent stay of the personnel and the population. Therefore, the created simplified mathematical model can also be used to assess the radiation impact on the environment in the implementation of emergencies of various kinds at other numerous radiation-hazardous facilities of the ChEZ.

COMMERCIAL AND BIOLOGICAL CHARACTERISTICS OF SILVER CARP OF DESNOGORSK RESERVOIR

The article presents fishing and biological characteristics of silver carp populations in Desnogorsk reservoir, formed after the mass stocking with large planting material in 2003-2012. A description of trade state and silver carp’s biological peculiarities is given. The efficiency of reclamation measures with the use of silver carp under conditions of the Smolensk NPP cooling reservoir is considered.