Isomer Selectivity in Aquatic Toxicity and Biodegradation of Cypermethrin

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• 作者：Weiping Liu ; Jay J. Gan ; Sangjin Lee ; and Ingeborg Werner
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2004
• 出版时间：October 6, 2004
• 年：2004
• 卷：52
• 期：20
• 页码：6233 - 6238
• 全文大小：97K
• 年卷期：v.52,no.20(October 6, 2004)
• ISSN：1520-5118

文摘

Synthetic pyrethroids (SPs) are widely used in both agricultural and urban regions for insect control.Unlike many other pesticides, SPs are chiral compounds consisting of stereoisomers. However,occurrence of isomer selectivity in environmental processes is poorly understood for SPs. Weevaluated isomer selectivity in toxicity of cypermethrin (CP) to Ceriodaphnia dubia and in itsbiodegradation by microbial isolates and in sediment. Among the eight enantiomers, two enantiomers(1R-cis-S and 1R-trans-S) were found to be toxic to C. dubia. Bacteria strains isolated from sedimentselectively degraded CP diastereomers and enantiomers. The trans diastereomers were preferentiallydegraded over the cis diastereomers. Of the two active enantiomers, 1R-cis-S was degraded slower,whereas 1R-trans-S was degraded faster than the other stereoisomers. Similar isomer selectivitywas observed during CP degradation in whole sediment. Since ecotoxicity is likely caused only bythe biologically active enantiomers, knowledge on isomer selectivity may improve our understandingof the ecological risks of CP and analogous SPs.Keywords: Isomer selectivity; enantioselectivity; cypermethrin; synthetic pyrethroids; biodegradation.