STATE OF BOTTOM SEDIMENTS OF THE VORONEZH RESERVOIR IN THE PLACES OF WATER DISCHARGE FROM THE TREATMENT FACILITIES OF THE CITY OF VORONEZH
The author considers the problem of pollution of the Voronezh water reservoir within the Voronezh urban agglomeration, in places of discharge of water from the treatment facilities of enterprises of the left bank. The paper uses the results of quantitative chemical analysis of bottom sediments performed on the basis of the ecological and analytical laboratory of the Faculty of Geography, Geoecology and Tourism of Voronezh State University, as well as monitoring data provided by the Federal Service for Supervision of Nature Management and the Department of Natural Resources and Ecology of the Voronezh Region. The database includes the results of monitoring from 2000 till 2021. On the basis of the composition of precipitation the author detected the history of accumulation of pollutants; as well she identified problem areas of the water reservoir in every study period. The author performed a spatio-temporal analysis of the contents of pollutants, calculated the "concentration clarkes" of heavy metals, according to which she created an ordered series for each observation point in ascending order of the attribute value. Based on laboratory studies and results of their statistical processing using correlation analysis the author draws some conclusions concerning the prospects for the Voronezh water reservoir existence and development. The correlations between the "concentration clarkes" and the amount of precipitation for the calendar and hydrological year have been verified. Based on the hydrogen sulfide content in different years, the author concludes about the range of concentration fluctuations and the formation of a cyclic process. She identified the zone of stable degradation of the water reservoir. Its formation occurs above and below the discharge from the municipal sewage treatment plants of the left bank of the city. The results of long-term observations of the quality of bottom sediments indicate a significant anthropogenic load on the part of the Voronezh urban agglomeration. Insufficient water purification, slow flow velocity and turbulence of natural water accelerate the process of natural eutrophication of the water reservoir.