PECULIARITIES OF THE GROUNDWATER CHEMICAL COMPOSITION WITHIN THE SAKSAGANSK-SURSK ORE DISTRICT OF THE DNIPROPETROVSK REGION

Abstract

The purpose of the research: to study the groundwaters in the Saksagansk-Sursk ore district of the Dnipropetrovsk region, which are used to ensure the economic and drinking needs of the local population. Data and Methods: A wide range of methods of obtaining, processing and interpreting of ecological-hydrogeochemical data, including field, chemical-analytical, comparative and graphical, were used. Mathematical and statistical methods were used in the processing of the obtained data. Visualization of the general chemical composition was performed with the help of specialized software tool GW_Chart. Results. The chemical composition of underground waters was studied, an assessment of their quality and suitability for potable use was made, the range of risks for the health of local residents-consumers of water was outlined, and the rationale for possible reasons for changes in their chemical composition during 42 years of operation (from 1978 to 2020) was provided. During the research, the authors found signs of metamorphosis of the chemical composition of groundwater. On the other hand, in the multi-year section, a general regularity was observed regarding the restoration of the state of the studied waters resources to the natural one, which is probably related to the decrease in the level of man-made load on the water environment over 42 years due to a significant decline in the rate of industrial development of uranium and iron ores within the Dnipropetrovsk region in general and the Saksagansk-Sursk ore district in particular. A preliminary conclusion was obtained that the ecological-hydrogeochemical conditions of the studied groundwater are primarily determined by: insignificant occurrences of water-bearing rocks (up to their emergence to the surface), close hydraulic connection with surface waters and adjacent aquifers, weak protection against surface pollution due to the lack of regionally sustained confining bed in its roof, the chemical composition of water-bearing rocks, as well as the tectonic conditions of the territory. The authors consider it necessary in further research to take into account the structural and geological features of the crystalline foundation of the studied area in connection with the spread of a wide range of metamorphic rocks and their weathering products, as well as the presence of tectonic faults within the first structural floor.