To investigate the contamination characteristics and potential ecological risks of pharmaceuticals and personal care products (PPCPs) in the Third Drain of Ningxia, 14 PPCPs were detected and analyzed using solid-phase extraction coupled with ultra-high performance liquid chromatography-tandem mass spectrometry. The results showed that these 14 PPCPs were detected in the Third Drain and its confluent streams, with total concentrations of 117.74-1947.64 ng·L-1 and 63.94-4509.39 ng·L-1, respectively. Detection ratios of gemfibrozil (GEM), caffeine (CAF), avobenzone (BM-DBM), benzophenone-3 (BP-3), 3-(4-methylbenzylidene)-camphor (4-MBC), and diethyltoluamide (DEET) were 100% in the drain. The highest-concentration pharmaceutical was GEM (7.78-721.84 ng·L-1), followed by CAF (41.74-246.86 ng·L-1), and the highest-concentration personal care product was DEET (3.17-219.91 ng·L-1), followed by BP-3 (56.92-150.14 ng·L-1). Concentrations of PPCPs at different sampling points exhibited spatial differences. The total PPCPs concentration increased dramatically and reached a maximum value after flowing through Pingluo County, then showed a decreasing trend downstream. Correlation analysis showed that 4-MBC was significantly positively correlated with COD (P<0.01). IBU, XMTD, TCC, and TCS were significantly correlated with NH4+-N (P<0.05). DIC, BF, CBZ, and DEET were significantly correlated with TN (P<0.05). The results indicated that concentrations of PPCPs were closely related to water quality indexes. Risk assessment showed that DIC, IBU, GEM, CBZ, CAF, and BP-3 had high risks, whereas BM-DBM, TCC, and TCS had moderate risks.
Keywords: ecological risk; pharmaceuticals and personal care product (PPCPs); pollution characteristic; the Third Drain; water quality index.