Health Implications and Socio-Environmental Drivers of Six Months of Drinking-Water Scarcity in the Capital City of Uruguay, South America

A historic freshwater deficit occurred in the capital city of Uruguay during the first six months of 2023, affecting over one and a half million people. During this period, the main source of freshwater used for potabilization in Uruguay was severely depleted. Saline water from the nearby Río de la Plata estuary was combined with freshwater in the potabilization plant. The inability to purify the mixed water resulted in the supply of non-potable water for daily use and direct consumption, causing a sanitary crisis. This study aims to identify relevant health risks posed by changes in the water quality parameters during the crisis and characterize its main drivers. During the first months of 2023, an increase in the concentration of chlorides (predominantly sodium chloride from saline waters), as well as turbidity and total suspended solids, exceeded the recommended limits for the potable water supply. This increased daily sodium intake generated particular health risks for individuals with hypertension, as well as for breastfeeding and pregnant women. Tap water quality was also compromised by an increased concentration of trihalomethanes, a by-product of the disinfection process. The prevailing justification for the crisis was a three-year period of climatic aridity. However, our analysis shows that a sustained forty-years increasing trend in water utilization for agriculture and other purposes also had a significant impact on the severity of the drought and the deterioration of water quality. A comprehensive analysis of water quality, its acute and chronic potential effects and the identification of the underlying causes is essential to prevent similar outcomes in the future.