THE ROLE OF THE «WATER–ROCK» SYSTEM IN FORMATION OF NATURAL WATER COMPOSITION OF THE SEVASTOPOL CITY

• Main Authors: Albina A. Khvashchevskaya, Dmitry A. Novikov, Yulia G. Kopylova, Irina A. Smetanina, Anatoliy V. Chernykh, Fedor F. Dultsev
• Format: Article
• Language: Russian
• Published: Tomsk Polytechnic University 2021-01-01
• Series: Известия Томского политехнического университета: Инжиниринг георесурсов
• Subjects: groundwater; hydrogeochemistry; «water–rock» system; equilibrium; continental salinity; anthropogenic pollution; sevastopol area; crimean peninsula
• Online Access: http://izvestiya.tpu.ru/archive/article/view/3005/2389

The relevance of the research consists in obtaining data on the geochemistry of springs and groundwater of the Sevastopol area as sources of drinking water supply and assessing their quality using modern analytical methods. The aim of the research is to reveal the role of interaction in the «water–rock» system, processes of continental salinization and anthropogenic pollution in formation of drinking water composition in the Sevastopol urban agglomeration. Methods. Sampling was carried out in accordance with generally accepted techniques. The laboratory study of the chemical composition by methods of titrimetry, ion chromatography, mass spectrometry with inductively coupled plasma, was carried out at the Problem Research Laboratory of Hydrogeochemistry of the Engineering School of Natural Resources of the Tomsk Polytechnic University. The theoretical foundations for solving the assigned tasks in this study were developed by professor S.L. Shvartsev at the Siberian Hydrogeochemical School. Results. During 2018–2019, field work was carried out on the territory of the Sevastopol city agglomeration to study the geochemistry of natural waters in order to assess the prospects for their use for drinking water supply. The studied waters are predominantly slightly alkaline (pH from 7,52 to 8,39), characterized by significant geochemical diversity in mineralization (from ultra-fresh 207,4 to brackish 1268,8 mg/dm3) and chemical composition. The application of the coefficients (Ca/Si, Mg/Si, Na/Si, Ca/Na, Ca/Mg, Si/Na, rNa/rCl and SO4/Cl) made it possible to identify homogeneous geochemical groups according to the formation of drinking water composition. The formation of their composition is influenced not only by the «water–rock» system, but also by the processes of continental salinization and anthropogenic pollution. The formation of the chemical composition from the perspective of the geological evolution of the water-rock system is in the initial stages. The equilibrium state of waters with carbonate minerals is achieved already in low-mineralized surface waters and the saturation of natural waters increases with the time of interaction with carbonate and carbonate-terrigenous formations. The composition of equilibrium minerals varies from calcite and dolomite in surface waters to their saturation in fissure-vein waters. For the waters of the regional fracture zone of carbonate and carbonate-terrigenous formations, the composition of the equilibrium minerals includes dolomite, calcite, siderite, rhodochrosite and magnesite. The equilibrium of waters with sulfate minerals can be traced only in some water points (the southern well in Kolkhoznoe, the Varnaly Fountain source, Stranny spring) and in waters with anthropogenic effect (Kolkhoznoe, Inkermansky and Orlovskii water intakes).