Geochemical assessment of the “surface water–bottom sediments” system in the zone of mining industrial technogenesis

Introduction. Tailings dumps are the most common by-product of the process of extracting valuable minerals and metals from mined ore. Their placement is accompanied by a violation of the natural properties of natural landscapes, changes in the geochemistry of soils and the hydrochemistry of the aquatic environment, the accumulation of heavy metals and toxicants in depositing media. The issues of geochemistry and stability of landscapes, the safety of natural and technical systems, the identification, study, assessment and forecast of their development in the conditions of increasing techno genesis is an urgent global problem. One of the most important directions in the geochemistry of mountain landscapes and mining and industrial ecology is the purposeful study of the relationship and interdependence of the processes of technogenic geochemical migration of the main and associated ore-forming elements into the environment with the technological processes of ore extraction and processing. The development of scientifically-based principles for the organization of control and monitoring of disturbed geo-systems in the conditions of techno genesis is not only an important fundamental research task, but has practical significance in order to preserve natural landscapes and mountain geo-systems. Purpose of research. Geochemical assessment of the “surface water-bottom sediments” system in the area of a copper-molybdenum deposit. Materials and methods. The research methodology is based on the theoretical foundations of landscape geochemistry. The object of the study is the system “surface water-bottom sediments” in the zone of technogenic influence of the tailings dump of a copper-molybdenum deposit. Field and standard physical-chemical methods, Excel graphics, geo-information analysis, 3D modeling Statistica were used. Discussion. Geochemical testing of the surface river in the tailings storage area revealed a significant enrichment of the aquatic environment with salt ions, which enter the surface water in the form of dam filtrate. The violation of the ratio of alkali metal ions, as well as the ratio of alkali-earth metal ions to alkali metal ions, which is a geochemical anomaly for fresh surface natural waters, is shown. As a result of constant filtration through the body of the tailings dam, heavy metals also enter the river water, primarily Cu, Mo, Fe, which, under conditions of an alkaline water environment, accumulate mainly at the bottom of the watercourse in the form of insoluble deposits. The coefficients of accumulation of metals in bottom sediments relative to clerks are obtained. The spatial dynamics of their distribution and variability along the riverbed are revealed, which makes it possible to predict the development of the situation in the zone of mining and industrial techno genesis. 3D models of the distribution of the analyzed metals from the properties of the pH medium, the main regulating factor of the formation of various forms of heavy metals, are obtained. Conclusion. It is shown that the hydro-geochemical features in the “surface water – bottom sediments” system of the river in the area of the tailings dam inherit chemical ore occurrence during Cu, Mo, Fe extraction. This indicates a technogenic transformation of the hydrosphere in a zone with a predominance of mining and industrial specialization of the deposit. The results obtained are of scientific interest as an empirical model for studying the process of formation of sedimentary ores, which, in turn, represents a fundamental aspect for the development of the theory of subsoil development design and studying the processes of formation of technogenic deposits.