Health Risks for the Population of the Voronezh Region Related to Drinking Water Quality

Abstract

The object of the study was the centralized drinking water supply system of the Voronezh Region. The purpose of the study was to assess health risks for the population of the Voronezh Region associated with drinking water quality. Materials and methods: The data of the regional drinking water quality monitoring system, which included monthly sampling and testing of water samples at 553 sites in 32 administrative districts and the city of Voronezh for 8 priority sanitary and chemical indicators (total hardness, concentrations of iron, manganese, nitrates, nitrites, boron, fluorine, and ammonium ions) for the years 2010-2019 were used. To achieve the objective based on monitoring studies of drinking water quality in the water distribution system, four generally accepted stages of risk assessment were implemented including hazard identification, evaluation of dose-response relationship, exposure assessment, risk quantification and characterization. When evaluating the exposure, four calculation scenarios were considered and probable body burdens for children and adults were calculated using the average long-term concentration and 95 percentile of concentration in a separate administrative territory. Results: Regional non-carcinogenic risks estimated on the basis of the average regional concentrations of priority pollutants did not exceed acceptable values (HQ < 1) for 6 of 7 ingredients. Unacceptable risk levels were observed in two of 33 administrative districts due to the presence of nitrates in drinking water (HQ ranged 1.34 to 2.95 for children and equaled 1.26 for adults). Detailed information for separate settlements (control points) using an aggravated scenario helped identify 4 rural settlements in 2 administrative districts with unacceptable risks for the child population of iron in drinking water (HQ up to 2.31), 230 settlements in 27 districts - of nitrates (HQ up to 9.51), one settlement - of boron (HQ = 1.17), and 35 settlements in 13 districts - of fluorine (HQ up to 4.17). Discussion: Summarizing the results of the regional studies of health risks for the population associated with the quality of drinking water, one can testify the shift of the problem to rural settlements where water treatment is practically null. The use of average concentrations of chemicals in drinking water in administrative districts proved to be insufficiently objective and having significant uncertainties. The reduction of uncertainties was achieved by a detailed review of the information for each monitoring site and the use of the 95th percentile concentration of the chemical to assess the health risks for children and adults. Conclusions: With a sufficient degree of certainty, the priority regional indicators determining the unacceptable level of non-carcinogenic risk (HQ > 1) associated with the quality of drinking water include elevated levels of nitrates, fluorine, boron, and iron.