Occurrence and distribution of pharmaceuticals in raw, finished, and drinking water from seven large river basins in China.

The occurrence of pharmaceuticals in the drinking water is a growing concern in China. In this study, we determined the concentration and distribution of 59 selected pharmaceuticals in raw, finished, and tap water samples from 79 drinking water treatment plants (DWTPs) in 15 cities, encompassing seven large river basins in China, using solid-phase extraction pretreatment and ultra-high-performance liquid chromatography-tandem mass spectrometry analysis. Forty-seven pharmaceuticals were detected in raw water samples, with detection rates of 1.27-96.20% and average concentrations of 0.09-128.87 ng/L. Forty-three pharmaceuticals were detected in finished water samples, with detection rates of 1.27-96.20% and average concentrations of 0.07-59.17 ng/L. Forty-two pharmaceuticals were detected in tap water samples, with detection rates of 1.27-94.94% and average concentrations of 0.07-58.43 ng/L. Purification methods implemented by DWTPs are capable of removing some pharmaceuticals from water treatment systems; however, low concentrations of pharmaceuticals were detected in drinking water, raising concerns about the possible human health implications of long-term exposure to low-dose pharmaceuticals. The detection and quantification of pharmaceuticals in municipal water samples presented in this study represent the most extensive analysis of commonly used pharmaceuticals and personal care products located in Chinese river basins.