title: Chiral Insecticide α-Cypermethrin and Its Metabolites: Stereoselective Degradation Behavior in Soils and the Toxicity to Earthworm Eisenia fetida.
abstract: The enantioselective degradation of the widely used chiral insecticide α-cypermethrin in soils has been investigated, and its main metabolites cis-3-(2',2'-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis-DCCA) and 3-phenoxybenzoic acid (3-PBA), which have potential environmental problems, have also been determined. The enantiomers of α-cypermethrin were separated on Chiralcel OD chiral columns by high-performance liquid chromatography (HPLC) under normal phase, and the metabolites were detected by gas chromatography (GC) after derivatization. The results of the degradation showed that α-cypermethrin dissipated in soils with relatively long half-lives of 12.70-47.08 days and obvious stereoselective degradation of the two enantiomers was observed in the five soils, with enantiomeric fraction (EF) from 0.55 to 0.61 after 42 days, indicating that (+)-(1R,cis,αS) enantiomer was preferentially degraded. cis-DCCA and 3-PBA were formed in all of the soils, and it was found that the amount generated was related to the soil pH. cis-DCCA was easily generated in the acidic soils, while more 3-PBA tended to be generated in the soil of pH over 7. To evaluate the impact on soil animals, the toxicity, including the combined toxicity of cis-DCCA, 3-PBA, and α-cypermethrin, to earthworm (Eisenia fetida) was studied. The results of enantioselective transformation of α-cypermethrin in soils and the toxicity of α-cypermethrin and its metabolites to earthworm have some implications for environmental risk and food safety evaluations.
authors: Department of Applied Chemistry, China Agricultural University , No. 2 Yuanmingyuan West Road, Beijing 100193, People's Republic of China.
authors: Guojun
authors: G
authors: Yao
authors: Department of Applied Chemistry, China Agricultural University , No. 2 Yuanmingyuan West Road, Beijing 100193, People's Republic of China.
authors: Xu
authors: X
authors: Jing
authors: Department of Applied Chemistry, China Agricultural University , No. 2 Yuanmingyuan West Road, Beijing 100193, People's Republic of China.
authors: Wang
authors: W
authors: Peng
authors: Department of Applied Chemistry, China Agricultural University , No. 2 Yuanmingyuan West Road, Beijing 100193, People's Republic of China.
authors: Xueke
authors: X
authors: Liu
authors: Department of Applied Chemistry, China Agricultural University , No. 2 Yuanmingyuan West Road, Beijing 100193, People's Republic of China.
authors: Zhiqiang
authors: Z
authors: Zhou
authors: Department of Applied Chemistry, China Agricultural University , No. 2 Yuanmingyuan West Road, Beijing 100193, People's Republic of China.
authors: Donghui
authors: D
authors: Liu
mesh_terms: D000818:Animals; D007306:Insecticides / Q000737:chemistry* / Q000633:toxicity*; D007700:Kinetics; D015394:Molecular Structure; D009835:Oligochaeta / Q000187:drug effects* / Q000254:growth & development; D011722:Pyrethrins / Q000737:chemistry* / Q000633:toxicity*; D012989:Soil Pollutants / Q000737:chemistry / Q000633:toxicity; D013237:Stereoisomerism
chemical_list: D007306:Insecticides; D011722:Pyrethrins; D012989:Soil Pollutants; C017160:cypermethrin
keywords: degradation; metabolite; stereoselectivity; toxicity; α-cypermethrin