Multipesticide Residues in Urban Tap Water across the Yangtze River Delta, China: Hazard-Based Prioritization, Regional Distribution, and Health Risk Assessment

Pesticide residues in drinking water are an increasing concern in the Yangtze River Delta, yet region-wide assessments remain limited. Herein, 244 widely used pesticides were investigated in tap water collected from 16 cities to characterize their occurrence, spatial distribution, hazard-based prioritization, and health risks. A total of 189 pesticides were detected, including 34 compounds with detection frequencies exceeding 50%. Although pesticide concentrations were generally below guideline values, a prioritization framework integrating exposure potential, persistence, bioaccumulation, and toxicity identified 10 high-priority pesticides. Spatially, pesticide concentrations were significantly higher in Shanghai (46.68 ng/L) and southern Jiangsu (34.91 ng/L) compared with Zhejiang (13.61–21.09 ng/L), associated with differences in agricultural land use and topographic conditions. Although infants exhibited the highest estimated daily intakes, cumulative hazard quotients for all populations remained below 1, indicating acceptable noncarcinogenic risk. These findings provide a region-wide integrated assessment of pesticide contamination in tap water, supporting risk-informed water-quality management.