Heavy metals and arsenic in fish resources in the confluence area of Ob and Irtysh rivers

Introduction. The long-term technogenic impact of mining, industrial, energy and agricultural enterprises in the Urals and Siberia on freshwater systems determines the need to assess the content of heavy metals and arsenic in fish in the largest rivers, the Ob and Irtysh.

Materials and methods. The study was conducted in 2004–2010 on the established network of ecological monitoring of ichthyofauna within 300–500 km of sites in the confluence of the Ob and Irtysh rivers. The content of Cr, Pb, Mn, Ni, Cu, Zn, Cd, Fe, Al, V, Hg, and As was estimated in the catches of six predatory and four peaceful fish species. Elements in samples were detected by atomic absorption method of analysis. Safety of fish resources was assessed by compliance of the most toxic Pb, Cd, As, and Hg in samples with the standards of SanPiN 2.3.2.1078–01 and TR CU 021/2011.

Results. During the observation period all fish in the Ob and Irtysh confluence area was shown to comply with sanitary and hygienic standards for heavy metal and arsenic content. Al, Fe, and Zn were noted to account for more than 90% of the accumulation of 12 elements considered in the ichthyofauna. A tendency towards an increase in the concentration of pollutants in fish is demonstrated. Over five years, the content of nine heavy metals in the Ob ichthyofauna increased by 3.6 times, and in the Irtysh fish by 4.5 times. The maximum levels of accumulation of elements are noted in bream, peled. and roach, and the minimum in ide, burbot. and pike, which is determined by their diet and must be taken into account when managing the fishing in the Yugra region.

Limitations. The content of toxicants was assessed in predatory and peaceful fish species caught during the sampling period, and expanding the list of analyzed ichthyofauna and the number of elements may become the subject of further research.

Conclusion. The increase in the content of pollutants in the ichthyofauna of the confluence of the Ob and Irtysh rivers determines the need for systematic monitoring of the accumulation of heavy metals and arsenic in the fish resources of the region and their compliance with standards.

Compliance with ethical standards. The study does not require submission of the opinion of the biomedical ethics committee or other documents.

Contribution:
Panov A.V. – research concept and design, writing a text, editing;
Korzhavin A.V. – writing a text;
Korzhavina T.N. – the collection and processing of the material.
All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.

Conflict of interest. The authors declare no conflict of interest.

Funding. The work was carried out within the framework of the state assignment of the Institute of Plant and Animal Ecology of the Ural Branch of the Russian Academy of Sciences, theme no. 122021000077-6.

Received: May 19, 2025 / Accepted: March 24, 2026 / Published: May 18, 2026

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