Methodical grounds and experience gained in implementing complex assessment of activities aimed at risk to public health and effectiveness of measures to improve the quality of drinking water in centralized water supply systems

Abstract

Introduction. Safe and qualitative drinking water is among the most significant conditions for minimizing environmental risks to public health. Our research goal was to develop and test methodical approaches to complex assessment of activities aimed at improving drinking water quality in centralized water supply systems. Within these approaches, effectiveness of such activities should be estimated as per health risk criteria. Materials and methods. Fuzzy set theory (fuzzy logic) was selected as relevant methodical grounds for estimating effectiveness of implemented activities. Our research objects were activities performed within regional programs and indicators of drinking water quality. A rate of public health risk was selected as a criterion to estimate effectiveness of an activity. Results. We developed a set of methodical tools that allowed assessing drinking water quality considering a variety of heterogeneous and instrumentally measurable indicators that were divided into several groups. Overall, we included more than 100 indicators that were grouped as organoleptic, sanitary-microbiological and parasitological, sanitary-chemical and radiological ones. We suggested a weighting factor for each indicator of drinking water quality. This weighting factor correlated with severity of health disorders under exposure to improper values of a specific indicator. Ranges of values for each indicator were scaled as per a degree of its hazard for human health and weighting factors were established for each indicator group. The total risk considered effects produced by all the indicator groups, their share contribution to a negative health outcome also taken into account. We determined a value of the membership function to establish where a specific risk would be found on the scale with risk rates from low to extremely high. Health risks were assessed prior to implementation of activities and after it. We also suggested a scale to measure effectiveness of implemented activities. Those activities that resulted in health risk reduction by less than 20% were estimated as low-effective ones. If a risk went down by 20-60%, activities were estimated as moderate or average-effective; a reduction by more than 60% indicated that implemented activities were effective or even highly effective. Limitations. The use of the existing information database on adverse effects and reference levels under exposure to environmental factors. Should new relevant data become available, this might result in the necessity to revise risk scales and weighting factors of specific indicators. Conclusion. We tested the suggested methodical approaches within actual projects implemented currently. The testing revealed their relevance to the existing tasks since these approaches facilitate proper assessment of activities as per a system of heterogeneous qualitative and quantitative indicators.