This paper presents the results of long-term monitoring (2019–2026) of Zn, Ni, Fe, Cu, Cr concentrations in surface waters and bottom sediments of the Kuibyshev Reservoir near Ulyansk city. The average concentrations of Zn, Ni, Fe, Cr exceed the maximum permissible concentrations for fishery water bodies by factors of 1.6–4.4. Hierarchical clustering and K means methods identified three groups of metals: seasonally dependent (Fe, Ni, Zn), conservative (Cu), and metals with signs of a point anthropogenic source (Cr). The interphase distribution coefficients lgKd were calculated: 3.35–3.39 for Cu and Zn, 2.80 for Ni, and 2.22 for Fe, indicating different accumulation capacities in bottom sediments. Using multiple linear regression, empirical relationships between metal concentrations and water temperature and pH were obtained. A forecast for the spring period of 2027 predicts exceedances of MPC: Fe – 7.9 times, Zn – 2.3, Ni – 1.6, Cr – 1.7 times. Copper remains the only metal with concentrations below the standard. The obtained results can be used to improve environmental monitoring systems and predict water quality in large lowland reservoirs.
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2. Bufetova M.V., Boldyrev K.A., Sobolev D.A. Modeling the Distribution of Heavy Metals between the Aqueous Phase and Bottom Sediments of the Sea of Azov. Regional Geosystems. 2025. Vol. 49. No. 3. P. 405 – 419.
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4. Volkova N.V., Tyurin S., Belousova M. Comparative analysis of spectrophotometric and atomic absorption methods for determining total iron in archaeological finds of bog ore. International Research Journal. 2024. No. 8 (146). P. 74 – 81.
5. Davydova O.A., Klimov E.S., Vaganova E.S., Vaganov A.S. Influence of physicochemical factors on the content of heavy metals in aquatic ecosystems. ed. by E.S. Klimov. Ulyanovsk: UlSTU, 2014. 167 p.
6. Rybkina I.D. Assessment of anthropogenic load on water resources and the efficiency of their use: a review of methodological approaches. Anthropogenic transformation of the natural environment. 2023. Vol. 9. No. 2. P. 55 – 67.
7. Seleznev V.A., Selezneva A.V. Content of chloride ions in the water of the Volga River. Bulletin of Voronezh State University. Series: Geography, Geoecology. 2021. No. 4. P. 34 – 41.
8. Tolkachev G.Yu. Comparative characteristics of the content and forms of existence of trace elements in bottom sediments of various areas of the Volga River. International Research Journal. 2017. No. 3 (57). Part 3. P. 85 – 89.
9. Ali M.M., Ali M.L., Islam M.S. et al. Preliminary assessment of heavy metals in water and sediment of Karnaphuli River, Bangladesh. Environmental Nanotechnology, Monitoring & Management. 2016. Vol. 5. P. 27 – 35.
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Aimetdinov R.R., Buzaeva M.V., Makarova I.A., Nezhneva K.G. Multifactorial modeling of the distribution of heavy metals in the "water – bottom sediments" system (using the example of the Kuibyshev reservoir). Chemical Bulletin. 2026. 9 (3). 3. https://doi.org/10.58224/2619-0575-2026-9-3-3

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