A role of technogenic chemical risk factors in the development of cognitive dysfunctions in children in a zone of exposure to the non-ferrous metallurgic enterprises

Introduction. Cognitive disorders in children reduce their social abilities and abilities to learn; therefore, correct diagnostics and prevention of such disorders is a pressing medical and social issue.

Materials and methods. The test group was made of two hundred sixty eight 4–7 years children lived and attended preschool children facilities in a zone exposed to emissions from a non-ferrous metallurgic enterprise. The reference group included 97 unexposed children of the same age. We analyzed ambient air quality on both territories. Cognitive processes were estimated by using a series of tests. Laboratory tests were aimed at estimating peroxidation-antioxidant balance, levels of neuromediators and neurotrophic factors in blood serum.

Results. The children from the test group had chemicals in their blood and urine in concentrations being both higher than the reference values and those detected in the reference group. Thus, manganese contents in their blood were by 1.3 times higher and aluminum contents in urine were by 1.7–2.2 times higher (р<0.001). Tests applied to estimate development of perception, logical thinking, attention and sensorimotor coordination, revealed that the exposed children were by 1.2–2.0 times less efficient in doing them than their counterparts from the reference group (р = 0.001–0.034). We established a relationship between likelihood of poorer perception and thinking and contents of manganese and aluminum in biological media (R² = 0.28–0.33). The children in the test group had by 1.2–1.5 times higher contents of malonic dialdehyde (25% contributed by aluminum and 31% contributed by manganese) and lipid peroxides (71% contributed by aluminum) in blood plasma. Antioxidant activity of blood plasma was by 1.2 times lower in the test group, nurotropin-3 contents were higher (13% contributed by manganese) and neuron-specific enolase in blood serum tended to decrease (58% contributed by aluminum).

Limitations. Age-related limitations concerning the applied series of tests.

Conclusion. Poorer perception and logical thinking, intensified lipid peroxidation and impaired balance of neurotrophic factors are target indicators necessary when developing relevant medical and preventive activities for children in a zone exposed to a non-ferrous metallurgic enterprise.

Compliance with ethical standards. The study was in accordance with the ethical principles of biomedical research set forth in the Declaration of Helsinki (as amended in 2008), the national standard of the Russian Federation GOST R 52379-2005 “Good Clinical Practice” (ICH E6 GCP), approved by the local ethics committee of the Federal Scientific Center for Medical and Preventive Technologies for Public Health Risk Management.

Patient consent. Each participant of the study (or his/her legal representative) gave informed voluntary written consent to participate in the study and publish personal medical information in an impersonal form in the journal "Gigiena i Sanitariya (Hygiene and Sanitation, Russian journal)".

Contribution:
Valina S.L. — study concept and design, statistical processing, text writing, editing;
Ustinova O.Yu. — the concept and design of the study, the collection of material and data processing, writing the text, editing;
Savinkov M.A. — collection of material and data processing, statistical processing;
Osheva L.V. — writing text;
Kobyakova O.A. — collection of material and data processing;
Eisfeld D.A. — the concept and design of the study.
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. 

Acknowledgement. The study had no sponsorship. 

Received: September 6, 2022 / Accepted: October 3, 2022 / Published: November 30, 2022