Determination of Key Quality Indicators for Organization of Potable Water Source Monitoring under Changing Climatic Conditions

Abstract

Background: In the context of deteriorating surface water quality, it is important to create a monitoring system to control constantly changing indicators that can affect the quality of both natural and potable water supplied to the population. Organic carbon is one of the key indicators reflecting the rate of production and destruction, climate change and anthropogenic impacts, safety and efficiency of potable water treatment. Objective: To study key indicators in the organization of potable water source quality monitoring. Materials and methods: In 2020–2021, monthly water sampling was carried out in a reservoir serving as the source of household and potable water supply of a large industrial city of the Sverdlovsk Region, and after water treatment. Water temperature, dissolved total, organic, and inorganic carbon, pH, the permanganate index (PI), hardness, and dry residue were measured. We then analyzed correlations between the indicators and assessed the efficiency of water treatment. Results: Maximum concentrations of Ctotal (54.3 mg/dm3) and Corg (36.0 mg/dm3) in the source water were found in January 2021. The predominance of Cinorg concentrations compared to Corg was mainly observed in warm months of the year. Water treatment generally decreased the content of Ctotal in potable water by 12–32 %, Corg by 12–47 %, Cinorg by 6–32 %, and PI by 28–68 %, except for a few months. In spring and summer 2021, we noted a decrease in PI in the reservoir; compared to other seasons, an increase in water pH was revealed in summer. We established a negative correlation between concentrations of organic carbon and water temperature. Conclusions: Monitoring studies of the surface potable water source have been organized. We revealed seasonal patterns of carbon changes and indicators of the mineral composition of water, and demonstrated the efficiency of water treatment.