Dynamics of heavy metals content in the Irtysh River water during the open water period within the boundaries of Omsk Region

Background.The relevance of the work is due to the need to monitor the water quality of the trans-boundary Irtysh River subjected to intensive anthropogenic impact and to identify patterns of changes in the concentrations of heavy metals (Fetotal, Zn2+, Cu2+, Mn2+, Hg2+) during the open water period within the boundaries of the Omsk region. The novelty of the research is due to the lack of current data on the content of heavy metals in the Irtysh River water in the Omsk region. Purpose.To estimate the level of heavy metals content in the Irtysh River water and to establish their dynamics during the period of open water within the boundaries of the Omsk region. Materials and methods.Materials of hydrochemical analysis of the Irtysh River in the territory of Omsk region in the period of open water (May-October) 2023 were used in the article. Sampling was carried out once a month from the surface water layer (0-0.2 m) by sampler in 15 points along the river. A total of 90 water samples were collected and analyzed during the study period. Hydrochemical analysis was carried out in the accredited laboratory of FGBU “Center for Laboratory Analysis and Technical Measurements in the Siberian Federal District” (Omsk) for 6 indicators: Fetotal, Zn2+, Cu2+, Mn2+, Hg2+. Concentrations of Fetotal, Zn, Cu, Mn were determined by inductively coupled plasma atomic emission spectrometry, Hg – by atomic emission method. Results.The average monthly values of maximum permissible concentrations for fishery waters were found to be exceeded for a number of indicators: Fe – 1.4-5.3 times, Zn – 1.1-7.6 times, Cu – 2.0-5.0 times, Mn – 1.2-1.9 times. Average monthly concentrations of mercury did not exceed the normative values. Concentrations of Fe, Cu and Mn depended on the season of the year - maximum values were observed in spring floods. During the summer-autumn low water period the concentrations of these elements decreased. For Zn ions no clear patterns in the change of content in natural waters by seasons of the year were revealed. Conclusion.Dynamics of heavy metal content (Fetotal, Zn2+, Cu2+, Mn2+, Hg2+) in the Irtysh River water during the period of open water in 2023 within the boundaries of the Omsk region is determined by the interaction of anthropogenic and natural factors. Concentrations of the mentioned heavy metal ions, except for mercury, along the whole course of the river within the boundaries of the Omsk region exceed MPCfish. Water quality does not meet hygienic standards.