Microelement composition of drinking water in centralized water supply of industrial cities of Dnipropetrovsk region

The purpose. Ecological and hygienic assessment of the quality of drinking water at the centralized water supply of industrial cities of the Dnipropetrovsk region by the content of trace elements from the group of heavy metals. Object and research methods. The analysis of the content of trace elements from the group of heavy metals in the drinking water of industrial cities of the Dnipropetrovsk region - Dnipro, Kryvyi Rih, Kamianske over a 5-year period was carried out. The evaluation of the obtained data was carried out in accordance with the requirements of the current legislation on the safety and quality of drinking water in accordance with SSRN 2.2.4-171-10, international recommendations and data from the scientific literature. Results. It has been established that in the Dnipropetrovs'k region over the 5-year study period, the percentage of non-standard drinking water samples for sanitary and chemical parameters ranged from 24.4-30.6% from centralized water supply systems, and 14.5-18.4% from water supply networks. The average long-term concentrations of metals in the drinking water of the studied cities ranged from 0.0001 mg/l for mercury to 0.19 mg/l for aluminum, which meets the MAC requirements, but the maximum values of the content of individual metals in all industrial cities exceeded the hygienic regulations, most pronounced for iron, which reached 60%. At the same time, the proportion of samples exceeding the hygienic standard in some years of the study was 5-12%. In the dynamics of the study, a gradual decrease of 14.2-54.5% in the concentration of lead in drinking water in all industrial and control cities was noted (p<0.05; R2= 0.51-0.78). A similar trend is also characteristic of the aluminum content in drinking water in Kryvyi Rih - a 2.5-fold decrease (p<0.001; R2=0.79) during the study period. At the same time, a significant increase in the content of a number of trace elements from the group of biotic and abiotic heavy metals was found in Kamianske, in particular copper and zinc - by 2.0-2.4 times (p<0.01; R2= 0.72-0.77), mercury and arsenic - by 1.3-1.9 times (p<0.01; R2= 0.87-0.92). The dynamics of concentrations of other heavy metals in the drinking water of the studied cities was unreliable. The sum of the ratio of the concentrations of trace elements from the group of heavy metals belonging to hazard classes I and II according to the sanitary and toxicological limiting sign of harmfulness ranges from 1.1 to 1.9, i.e. the simultaneous presence of these metals in the drinking water of industrial cities exceeds the safe level regulated by SSRN 2.2.4-171-10. Conclusions. The results of the conducted research indicate the urgency of the problem of ensuring the quality and safety of drinking water intended for human consumption and the need for further improvement of water treatment and control methods at all levels. Keywords. Trace elements, heavy metals, drinking water, content, pollution, impact, public health.