[Contamination Characteristics and Ecological Risk Assessment of Pharmaceuticals and Personal Care Products (PPCPs)...

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.