Human Health and Ecological Risk Assessment, and Prioritization of Contaminants of Emerging Concern in Asia’s Largest Artificial Freshwater Lake

The ecological risks, health hazards, and prioritization of contaminants of emerging concern (CECs) in drinking waters have attracted considerable attention from researchers. To provide a scientific basis for ensuring water quality safety in the core water source area of the South-to-North Water Transfer Project, this study conducted a multi-dimensional risk assessment and prioritization of CECs in the Danjiangkou Reservoir in China. A total of 109 CECs were identified across the 28 sampling sites, with the total concentration ranges of 82.51 ng·L –1 to 1436.57 ng·L –1 . The optimized risk quotient (RQ f ) indicated that 12 CECs posed low to high ecological risks. The joint probability curves indicated that atrazine-desisopropyl, hexazinone, imidacloprid, and thiacloprid posed low risks, with the maximum risk product ranging from 0.41%–0.82%. Health risk assessment revealed that the carcinogenic risk of all CECs was below the acceptable threshold. Nevertheless, ofloxacin might pose a potential threat to sensitive populations due to its high persistence and bioaccumulation. The total non-carcinogenic risk was also below the acceptable threshold of 1, with methamidophos and dichlorvos being the major contributors due to their neurotoxicity. Based on the Environmental Health Priority Index method, 97 CECs were prioritized by incorporating 6 indicators, including detection concentration and frequency, bioaccumulation, persistence, ecological risk, and health risk. Ten CECs, including hexazinone, methamidophos, TCEP, adamantamine, dichlorvos, TEHP, imidacloprid, TnBP, TBEP, and TEP were identified as medium-priority contaminants. The findings offer important insights for the risk assessment and prioritization framework of CECs in drinking water source protection. • A total of 109 CECs were detected in the Danjiangkou Reservoir. • Twelve CECs posed low to high ecological risks to aquatic organisms. • Ofloxacin might pose a potential threat to sensitive populations. • The EHPi method revealed that 10 CECs were medium-priority pollutants.