Cyflumetofen Degradation in Different Aquatic Environments and Identification of Hydrolytic Products

Abstract Pesticides that persist in the aquatic environment may be transformed into complex metabolites, which are hazardous and have potentially harmful impacts on organisms. Cyflumetofen (CYF) is a novel benzoylacetonitile acaricide that has a good insecticidal effect and is widely used in China. However, the behavior of CYF in an aquatic environment has seldom been reported. In this study, the hydrolysis of CYF and its main metabolites, 2-(trifluoromethyl)benzoic acid (B-1) and 2-(trifluoromethyl)benzamide (B-3), were studied at pH values of 4.0, 7.0, and 9.0 and at temperatures of 25, 35, and 45 °C, in both Milli-Q water and surface water systems. It was demonstrated that CYF hydrolysis in different aqueous environments follows first-order kinetics, with half-lives ranging from 1.2 h to 23.3 d in a buffer solution. CYF hydrolyzes faster in alkaline conditions (P   0.05), and the degradation rate in surface water is faster than that in Milli-Q water. The formation concentration of B-1 was significantly higher than that of B-3, and a large number of B-1 and B-3 metabolites still existed in the aqueous environment after CYF was almost fully degraded. The pathway of the main hydrolysis of CYF was also proposed. The results of this study are of practical significance in providing guidance for an ecologically and environmentally safe use of CYF.