Genetic factors of toxic effects development in pollution liquidators of the former factory with mercury electrolysis technology

Introduction. According to genetic factors, it is possible to determine the degree of manifestation of the toxic effects of mercury. The latter justifies the assessment of the genetic status of the exposed contingent in order to identify hypersensitive individuals in whom adverse health effects can be realized when exposed to relatively low levels of the toxicant.

The study aims to research the distribution of genotypes of some polymorphic variants of genes of the xenobiotic biotransformation system, heat shock proteins and tumor necrosis factor in the contingent involved in liquidation measures, as well as to identify individuals with a high prognostic risk of toxic effects due to exposure to mercury.

Materials and methods. We conducted genotyping of 231 people (men only): 193 employees of the Ministry of Emergency Situations (MES) of Russia in the Irkutsk Region and 38 employees of the Federal Environmental Operator (FEO) involved in the elimination of mercury pollution at the industrial site of the mercury electrolysis plant and adjacent facilities on the territory of a former chemical plant in Eastern Siberia. The researchers used real-time PCR and PCR-RFLP methods to study polymorphic variants of the genes CYP1A1 (rs1048943), GSTP1 (rs1695 and rs1138272), TNF-α (rs1800629) and HSPA1B (rs1061581).

Results. For the polymorphism of the GSTP1 gene (rs1695), we have identified an increase in the frequency of AG genotypes (p=0.043) and a decrease in the frequency of GG genotypes (p=0.048) in employees of the MES compared to those from the FEO group. The researchers didn’t detect carriers of the TT genotype for the polymorphic locus GSTP1 (rs1138272) in both examined groups. There was the carriage of the rare GG-CYP1A1 homozygote only in one MES employee. We found that 33 MES employees and 3 examined from the FEO group who are carriers of the GG-HSPA1B (+1267A/G) genotype have a high predictive risk of developing toxic effects due to mercury exposure. The experts discussed the data obtained with the results of genotyping of former mercury electrolysis shop workers who were chronically exposed to metallic mercury vapor. The experts have reviewed the data obtained from the results of genotyping of former employees of the mercury electrolysis shop who were chronically exposed to metallic mercury vapor

Limitations. The limitations, first of all, should include the number of examined individuals in the FEO group, as well as the lack of data on deletion polymorphisms of the GSTT1 and GSTM1 genes, potentially having a significant role in the toxicokinetics of mercury.

Conclusion. The study has revealed 36 carriers of the GG genotype of the polymorphic locus +1267A/G of the HSPA1B gene associated with a high prognostic risk of toxic effects associated with exposure to mercury among the employees of the Ministry of Emergency Situations (MES) and the FEO involved in liquidation work. Taking into account the forthcoming volume and duration of work related to the demercurization of the territory of the former factory with mercury electrolysis technology and the surrounding area it is advisable to take into account the results obtained when monitoring the health status of the liquidators.

Ethics. We have received voluntary informed consent, approved by the Committee on Biomedical Ethics (Protocol No. 6 of 10.03.2020), from each employee being examined.

Contribution:
Chernyak Yu.I. — concept, research design, final data processing, text writing and editing;
Merinova A.P. — collection of samples, implementation of techniques and data processing.

Acknowledgment. The authors express their gratitude to the staff of the Institute's clinic for organizing the examination and forming groups, as well as to Professor RAS, Dr. of Sci. (Med.), Prof. O.L. Lakhman for useful comments when discussing the manuscript.

Funding. The study was supported within a framework of State Assignment for exploratory scientific studies for East-Siberian Institute of Medical and Ecological Research (No. АААА-А20-120100190008-8).

Conflict of interests. The authors declare no conflicts of interests.

Received: 26.07.2022 / Accepted: 15.09.2022 / Published: 28.09.2022

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