Abstract:
Objective To evaluate the health risks of arsenic (As), cadmium (Cd), hexavalent chromium (Cr6+), lead (Pb), and mercury (Hg) in drinking water in the rural areas of a city in Shaanxi Province, China, 2017—2022.
Methods The monitoring data of 4 153 drinking water samples in rural areas of a city in Shaanxi Province from 2017 to 2022 were analyzed. The health risk assessment model recommended by the United States Environmental Protection Agency (US EPA) was used to calculate the health risks of five metals and metalloids to local residents through drinking water at different exposure levels.
Results At general exposure level, the total hazard index (HI) of five metals and metalloids in drinking water in the rural areas was 0.344, and the total cancer risk (RT) was 3.99×10-4. At high exposure level, HI was 1.81 and RT was 1.99×10-3. Concentration stratification analysis showed that the concentrations of Cd, Cr6+, and Hg were higher in the dry season than in the wet season. The concentrations of As, Cd, Cr6+, and Pb were higher in river water than in other types of source water, and the concentration of Hg was the highest in shallow well water. The concentrations of five metals and metalloids were higher in partially treated water samples than in untreated and completely treated water samples. The health risk stratification analysis showed that the health risks of five metals and metalloids through drinking water were higher in men than in women and higher in children than in adults.
Conclusion The non-carcinogenic risk and total hazard index of the five metals and metalloids in drinking water in the rural areas of a city in Shaanxi Province from 2017 to 2022 did not exceed the acceptable values at general exposure level, and the total hazard index exceeded the acceptable value at high exposure level. The carcinogenic risk of Cr6+ was slightly higher than the maximum acceptable value in the range of 10-6-10-4 at both general and high exposure levels, and thus Cr6+ warrants special attention in risk management.