Distribution and Health Risk Assessment of Neonicotinoid Insecticides in Drinking Water of Major River Basins in China

In this study, the raw water, finished water, and tap water of various waterworks in major river basins of China were collected for the determination of the neonicotinoid insecticides (NNIs). The results showed that one or more NNIs were detected in 81.2% of the water samples, and the total concentration of NNIs (∑NNIs, sum of eight NNIs) ranged from 0.10 to 210.33 ng/L, with a median of 7.08 ng/L. Thiamethoxam, imidacloprid, and clothianidin had the highest contribution rate among the major ∑NNIs detected. The concentration of ∑NNIs detected in the Pearl River was higher than that in other river basins, with a median of 51.11 ng/L. During the dry season, the detection rate of ∑NNIs was 77.4%, with concentrations ranging from 0.10 to 210.33 ng/L. During the wet season, the detection rate of ∑NNIs was 85%, and the concentration of ∑NNIs ranged from 0.10 to 117.03 ng/L. The estimated daily intake (EDI) of NNIs in the raw water and drinking water of each river basin is less than the reference dose (RfD) of imidacloprid. The potential risk of NNIs can be reduced by further optimizing the water treatment processes.