Justification of Temporary Deviations in Drinking Water Quality Given New Scientific Data for Health Risk Assessment

Abstract

Introduction: Since 2024, Russian R 2.1.10.3968-23, Guidelines for assessing health risks from exposure to chemical environmental pollutants, have been in effect, which opens up new opportunities for analyzing adverse human health effects of environmental factors. Objective: To justify temporary deviations in drinking water quality taking into account new scientific evidence and using the methodology of human health risk assessment. Materials and methods: For the current study, we selected 214 results of water quality testing before supply to the urban distribution system for the years 2019–2022. The statistical analysis was conducted in Microsoft Excel using descriptive statistical techniques. Temporary deviations were justified for indicators which median values exceeded hygienic standards. Risk assessment was conducted according to both cancelled and updated Guidelines and included substances with established reference doses and carcinogenic potency factors. We calculated carcinogenic risks, non-carcinogenic hazard coefficients and indices using standard exposure factors. Results: The statistical analysis showed that median levels of boron and magnesium exceeded hygienic standards. According to the results of health risk assessment, values of carcinogenic and non-carcinogenic risks were at an acceptable level. Unacceptable levels were mainly determined for the exposure to arsenic, the concentration of which can be taken as zero in accordance with the new guidelines. Boron exposure did not significantly contribute to risk levels, while for magnesium the reference dose is absent. Discussion: Questions are raised related to the lack of reference doses for certain chemicals and exclusion of some pollutants from the analysis. Conclusion: The health risk assessment values calculated in accordance with the updated guidelines are within the acceptable range, indicating that there is no threat to health. This finding supports the establishment of temporary deviations for boron and magnesium.