Levels, D,S-patterns and source identification of metals and metalloids in river waters of the gas-producing region in the north of Western Siberia (Pur River basin)

The study aimed to determine the levels, spatial and temporal variability of the concentrations, and forms of migration of metals and metalloids in the Pur River basin, which is one of the most important oil and gas producing areas in the north of Western Siberia. The study is based on the results of hydrological and geochemical studies conducted in 2021-2023 during the summer low water and spring flood periods. We found generally low content of dissolved metals and metalloids in water of the Pur River and its tributaries, not exceeding the world average values, except for Fe and Zn. Levels of metals and metalloids in the suspended matter were also lower than the global averages, except for Fe and Mn. Changes in the content of dissolved and suspended forms of metals caused by hydroclimatic factors and anthropogenic impact were determined. Near cities, the maximum concentrations of Zn, Cd, Cu and other metals in suspended matter are 3-5 and more times higher than the baseline values. Analysis of EF values for median contents allowed to identify the association of elements with considerable and high enrichment in suspended matter: Fe, Mn, Sb, As, Cd and Zn. The maximum EF values ranged from 25 to 45, which corresponds to very high degree of enrichment. Three groups of chemical elements were identified on the basis of D,S-analysis.