Spatial and temporal assessment of surface water quality in municipal water bodies of the city of Tyumen

The purpose of the study is a spatio-temporal assessment of the quality of surface water for water bodies of municipal importance in Tyumen in the current conditions of urban economy. A grouping of 16 municipal ponds and waterlogged quarries was carried out according to the results of the water quality assessment. The period of water sampling for the study: 2018–2021; spring, summer and autumn dates of each year of study, a total of 12 observation dates. Analyzed indicators: biochemical oxygen consumption (BOD5), chemical oxygen consumption (COD), dry residue, General, Zn, Na, chloride-anions. The results of the study: all municipal reservoirs of Tyumen during the study had repeatedly exceeding the established values of the maximum permissible concentrations for water bodies of fishery significance in three or more indicators. Most municipal facilities are included in the group of highly hazardous reservoirs, characterized by fixing the excess of the MPC value in water for several indicators, including the heavy metal Zn. The group of reservoirs of the background concentration of pollutants includes the watered quarry “Willow”, in which exceedances were recorded for BOD5, COD and Fe, which is typical for Tyumen natural conditions. The waterlogged quarry “Chistye” and the pond “On Dambovskaya” are classified as extremely dangerous reservoirs, they are characterized by the presence of exceeding the values of the MPC in the water for all indicators, with the exception of the dry residue. The waterlogged quarry “Maisky” is classified as a group of extremely dangerous degraded reservoirs, since during the analyzed time period it recorded exceedances of the MPC values in the water for all indicators. On the example of bottom sediments of the pond “Yuzhny”, a partial section of the ratio of pollutant content at 2 sampling points within the boundaries of the municipal reservoir is shown. Based on the results of the study, recommendations are given for the city authorities to conduct a differentiated approach to the organization of water use for water bodies from different groups.