Distribution and ecological risk evaluation of 12 chiral pesticides in surface waters and surface sediments of the Wuhan section of Yangtze River basin (China)

To research the environmental behavior of chiral pesticides in waters and sediments in the Wuhan section of the Yangtze River basin and evaluate their ecological risk, a quantitative method for the detection of 12 chiral pesticides was established based on ultra performance liquid chromatography-electrospray (UPLC) ionization (ESI) tandem triple quadrupole mass spectrometry. The analysis results suggest that the overall a low detection rates and concentrations of the 12 chiral pesticides in surface waters and surface sediments, but the concentrations of paclobutrazol, tebuconazole and hexaconazole were relatively high among them. All the chiral pesticides detected in this study area have stereoselectivity, with S-Paclobutrazol and (-)-Hexaconazole being preferentially degraded in most of the study area, while the stereoselective degradation pattern of tebuconazole was more complicated. ECOSAR simulation method allows deriving that hexaconazole poseded a low (or lower) ecological risk to aquatic algae and paclobutrazol had a low (or even higher) ecological risk to whole aquatic organisms. The levels of most other chiral pesticide residues were acceptable.