REGIONAL FEATURES OF THE FORMATION OF THE HYDROCHEMICAL REGIME OF RIVERS IN UKRAINE UNDER CLIMATE CHANGE CONDITIONS

Abstract

The ecological condition of the aquatic environment is determined by water availability, climatic characteristics of the region, pollutant load, and self-purification capacity. The natural component of the formation of the salt background of surface waters requires constant due attention. The mineralization of water basins of rivers of Ukraine is determined by the physical and geographical conditions of the location of the basins themselves, the water regime of watercourses and the level of permissible anthropogenic load (wastewater discharge from urbanized areas and surface runoff). The mineralization of water is determined by the phases of the hydrological regime, and the distribution of the main factors of its formation differs in composition, location and impact of human activity. However, the processes of formation of the corresponding system depend on hydrochemistry, the number of ecotones and self-purification processes. In particular, a high self-purification index was observed in the rivers Horyn, Styr, Sluch, Western Bug, Desna, Teterev, Ros. Vorskla, southern river basins of the Black and Azov Seas, however, ichthyological crisis situations were formed in some locations. These processes are influenced by the acidification of the aquatic environment (pH of the Horyn, Styr, Sluch, Desna, Teterev), as well as the toxicity index by ions (from Horyn to Vorskla). In the Shatsk Lakes basin, with the minimization of the impact of atmospheric precipitation (mineralization 40-50 mg/dm³), the main source of salt composition is groundwater from fractured rocks (karst phenomena). Effective purification can be judged by the biopermeability of live food for ichthyofauna. A sharp increase in the high mineralization of rivers in southern Ukraine has been observed, caused by rising air and water temperatures, as well as a decrease in water volume in rivers and reservoirs.