Simultaneous evaluations of occurrence and probabilistic human health risk associated with trace elements in typical drinking water sources from major river basins in China

Water quality is among the most important environmental issues related to sustainable development in China, especially to ensure national drinking water safety. Here, we investigated the concentrations of 19 trace elements in major drinking water sources from five major river basins in China: Yangtze River Basin, Yellow River Basin, Huai River Basin, Hai River Basin, and Liao River Basin. Water quality, human health risk, and probabilistic health risk were evaluated using statistical analysis, as well as the water quality index (WQI), hazard quotient, hazard index (HI), carcinogenic risk (CR), and Monte-Carlo simulation. The distributions of the trace element concentrations differed somewhat among the five river basins. Regardless, the concentrations of all trace metals were within the permissible drinking water quality limits set by China, WHO, and US EPA and Chinese surface water standards (Grade I). Based on the low WQI values, all five river basins were categorized as having "excellent" water quality. In the non-carcinogenic risk assessment, the HI values for both adults and children were within the safe limit (<1.0), indicating no adverse health effects on the human body via daily oral intake and dermal absorption. By contrast, the CR values for As exceeded the Chinese limit of 1.0 × 10-6, with a higher risk for adults, via ingestion as the main exposure pathway. Sensitivity analysis identified exposure duration and ingestion rate as the most sensitive variables affecting the probabilistic risk for adults, while As concentration and exposure duration were the most sensitive variables for children. Overall, the findings indicate that As in drinking water may pose a detrimental health risk to the exposed population; therefore, regulation and management should focus on As monitoring and evaluation in the major river basins of China.