MONITORING OF GROUNDWATER QUALITY IN LISTVYANKA SETTLEMENT (SOUTHWEST COAST OF LAKE BAIKAL)

A systematic monitoring of the hydrosphere is important and necessary to maintain a good ecological sta-tus of Lake Baikal. The article presents the results of a five-year monitoring of the groundwater and surface waters quality in Listvyanka settlement. The goal is to determine the contamination level of drinking water supply system. In the field studies, portable measurement devices were used for monitoring temperature, pH, Eh, electrical water conductivity and water levels in wells, and water samples were taken for a complete chemical analysis. The analysis of the macrocompo-nent composition of water was carried out by various methods (flame photometry, volumetric titration, weight method, colorimetry) at the Center for Geodynamics and Geochronology of the Institute of the Earth's Crust SB RAS (Irkutsk); the trace element composition was determined by the ICP MS method on the Element-2 device (Finnigan MAT, Germany) at the Institute of Geochemistry SB RAS (Irkutsk); microbiological analysis of water samples was performed at the Irkutsk Interregional Veterinary Laboratory; the analysis of isotope characteristics (S18O and SD) of water samples was per-formed in the Laboratory of Hydrogeology of the Institute of the Earth's Crust SB RAS (Irkutsk) on a Picarro L2140-i gas analyzer.The results obtained indicate a change in macrocomponent composition of waters and an uneven distribution of pollutants over the area. The content of 42 trace elements in groundwater and river waters generally does not exceed the regulatory requirements for drinking water; the exceptions are Fe and Mn. Ten wells do not meet the sanitary and epidemiological rules and norms SanPiN 2.1.4.1074-01. The main sources of groundwater pollution are leaking septic tanks of numerous hotel complexes located in the valleys and on the valley slopes. The processes of water pollution and restoration of natural regime of water are of different intensity. For groundwater and river waters, there were determined the relative concentrations of stable isotopes of hydrogen and oxygen (SD and S18O), and SD=5.5307 center dot S18O-31.815 rela-tionship and the deuterium excess values were obtained. Characteristics SD and S18O are the bases of the isotope database for the aquatic environment of Listvyanka settlement.