Introduction. Long-term mercury exposure in the Usolye-Sibirskoye environment could create the preconditions for adverse health effects in children born in the area.

The objective. To assess the biochemical parameters in schoolchildren living in an environmentally sensitive area.

Materials and methods. A total of examined one hundred ninety one child aged of from 11 to 16 years was and divided into two groups: Group 1 (main group) – individuals with mercury excretion; Group 2 (comparison group) – individuals without it. All subjects were assessed for indicators reflecting the state of various types of metabolism. Comparison of groups were performed using the nonparametric Mann–Whitney U-test.

Results. Children in the main group had lower concentrations of total protein (p = 0.02) and albumin (p = 0.0002) in the blood serum compared to group 2. They were also characterized by higher concentrations of ceruloplasmin (p = 0.04), magnesium (p = 0.05), aspartate aminotransferase (p = 0.048). Children in group 1 had higher values of the atherogenic index (p = 0.0002), cholesterol proatherogenic fraction concentration (po = 0.02), as well as lower levels of the antiatherogenic fraction (p = 0.0002), apolipoprotein A1 (p = 0.003), ferritin (p = 0.04), vitamin D (p = 0.02), calcium, imbalance in the ratio of thyroid stimulating hormone (TSH), and free thyroxine (T4).

Limitations. The study’s limitations included adolescents aged 11 to 16 years, whose parents and they themselves permanently resided in Usolye-Sibirskoye and the surrounding area downwind of the Usolye-Sibirskoye industrial site.

Conclusion. Adolescents excreting mercury exhibited lower protein metabolism parameters, proatherogenic lipid metabolism, and signs of latent iron deficiency. They also had lower vitamin D levels, lower total calcium levels, lower TSH and T4 levels, and higher levels of thyroid peroxidase antibodies.

Compliance with ethical standards. The study was conducted in compliance with the ethical standards of the Helsinki Declaration (last revised) and Order No. 200n of Russian Federation Health Ministry the dated April 1, 2016. Conclusion of the local ethical committee of the East-Siberian Institute of Medical and Ecological Research No. 1 dated of December 21, 2023. All participants and their legal representatives gave informed voluntary written consent to participate in the study.

Contribution: Kudaeva I.V. – the concept and design of the study, editing, writing text, final version approval; Kurchevenko S.I. – statistical processing, writing text; Lakhman O.L. – the concept and design of the study, final version approval; Efimova N.V. – the concept and design of the study; Kucherova N.G. – collection and processing of material, statistical processing; Lysenko A.A., Starkova A.S., Prokhorova P.G., Rybakova A.P. – collection and processing of material. All authors are responsible for the integrity of all parts of the manuscript.

Acknowledgment. The authors express their gratitude to I.V. Mylnikova, senior researcher at the Laboratory of environmental and hygienic research, for her assistance in managing the examination of children, and to O.V. Bukshina, research assistant at the Laboratory of analytical ecotoxicology and biomonitoring, for conducting research on determining mercury in urine.

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

Funding. The study had no funding and was performed within the framework of the funds allocated for exploratory scientific research of East-Siberian Institute of Medical and Ecological Research.

Received: October 24, 2025 / Revised: October 29, 2025 / Accepted: November 3, 2025 / Published: December 19, 2025