Current trends in chemical hydrology of the Pavlovsky Reservoir on the Ufa River

The paper presents an analysis of long-term dynamics and current trends in the hydrochemistry of the Pavlovsky Reservoir by 10 chemical indicators at seven water intake points. The choice of 10 chemical elements was justified in previous studies mentioned in the paper. This approach allows using the observation data of the Bashkir FSBI (Federal State Budgetary Institution Bashkir Hydrometeorology and Environmental Monitoring Department), previous studies conducted in 1986–88 and in 2000 and the results of the present research (2018–2019) making it possible to track the dynamics of changes in the hydrochemical composition of water over 30 years (from 1986 to 2018). It was revealed that throughout the reservoir, from its beginning to the upper reaches, the content of Sr2+, Mn2+ and petroleum products in the water decreases; Zn2+, Hg2+, phenols and organic substances increase; Fe total (Fe2+ + Fe3+), P total are evenly distributed (according to PO43-), Cu2+. The study of the features of the long-term dynamics of the hydrochemical indicators of the Pavlovsky Reservoir allows for determining trends in the state of the ecosystem of the water body and proposes measures to preserve the operational properties of the reservoir.