THE NATURAL WATERS’ QUALITY ASSESSMENT AT THE YAMALO-NENETSK AUTONOMOUS DISTRICT SCIENTIFIC GROUNDS (PUROVSKIY, TAZOVSKIY, SHURYSHKARSKIY, POLYARNO-URALSKIY)

Surface water bodies are most vulnerable to chemical pollution. Objective: to study the hydro/chemical indicators of the state of surface waters of the Yamalo-Nenetsk Autonomous District and to assess their quality. In 2018, original studies of water bodies located in scientific testing grounds of the Yamalo-Nenetsk Autonomous District were conducted. The reservoirs are located in the zone of the northern and middle taiga, southern tundra and forest-tundra, on the eastern slope of the Polar Urals. Sampling was carried out according to generally accepted methods. In the surface water samples, the main hydro chemical parameters were determined. For an integrated assessment of water quality, the water pollution index (WPI) was used. The surface waters of the examined water bodies belong to low mineralized waters with low concentrations of basic anions and cations. All studied waters in terms of BOD5 are classified as dirty and very dirty waters. In the surface water samples of the Polar Urals, high concentrations of benz [a] pyrene were detected. The waters of the Tazovsky landfill belong to moderately polluted waters, the waters of the Purriver are polluted, the waters of the Syny river are dirty. The water bodies of the Polar Urals are very dirty. High values of IZV are associated with elevated concentrations of benz(a)pyrene, BOD5, manganese, copper, zinc, and aluminum. The water pollution index more characterizes the unfavorable biogeochemical situation in the region. An elevated level of technogenic pollution due to benzo(a)pyrene, the source of which is the combustion of fossil fuels (pyrogenic), is established in the water bodies of the Polar Urals. The surface waters of the surveyed water bodies are low-quality waters.