Screening triazine herbicides in drinking water in the Yangtze River Delta, China: Occurrence and health risk

Triazine herbicides are toxic to humans and aquatic organisms. Current research on triazine herbicides in wa-ter has been focused on atrazine and has largely ignored the potential risks of other herbicides, particularly in drinking water. In this study, the drinking water of the Yangtze River Delta region was tested for 13 triazine herbicides using high-throughput organic analysis testing combined with high volume solid-phase extraction, and 11 of these herbicides were detected in tap water (TW) (mean: 5.29 & PLUSMN; 6.1 ng/L). Terbutryn had the highest percentage in TW, which may be related to the treatment process of water treatment plants. Nine triazine her-bicides were detected in barreled water (BW) (mean: 1.67 & PLUSMN; 0.538 ng/L). The concentrations of most triazine herbicides were higher in TW than in BW. Water source quality significantly impacted the distribution of triazine herbicides in BW, with deep treatment reducing the content of some pesticide residues. The difference in herbi-cide types in drinking water was primarily influenced by both the water treatment process and the source water. There were no significant differences between urban and suburban areas, with larger differences between cities. Triazine herbicides were ingested more through TW, with an estimated daily intake 3-4 times higher (range: 0.018-0.05 ng/kg-bw/d) than BW (range: 0.006-0.016 ng/kg-bw/d). The acute toxicities of the two groups of drinking water samples were negligible. This study provides the first overview of the occurrence, regional dis-tribution characteristics, and associated potential human health risks of triazine herbicides in drinking water in China.