title: Fate and stereoselective behavior of benalaxyl in a water-sediment microcosm.
abstract: The environmental behavior and stereoselectivity of the chiral fungicide benalaxyl and its chiral metabolite benalaxyl acid in water, sediment, and water-sediment microcosms were studied. The microcosms were incubated at 25 °C with light or under darkness. The influencing factors such as light and microorganism were investigated. The results showed that benalaxyl had half-lives of >21 days in the microcosm system and that the metabolite benalaxyl acid could exist in the microcosm for >70 days. Benalaxyl was mainly transformed through microbial degradation, and thus sediment microorganisms played a major role in the dissipation of benalaxyl in the aquatic microcosm. The stereoselective behavior of benalaxyl and benalaxyl acid was also investigated. (-)-Benalaxyl was preferentially degraded in the microcosm, resulting in an enrichment of the more toxic enantiomer (+)-benalaxyl, which may cause higher risk to the aquatic system. Moreover, (-)-benalaxyl acid was preferentially formed in the microcosm. The enantioselectivity of the enantiomers in the microcosm should be taken into consideration for an accurate risk assessment.
authors.affiliation: †Department of Applied Chemistry, China Agricultural University, Beijing 100193, People's Republic of China.
authors.forename: Mingke
authors.initials: M
authors.lastname: Liu
authors.affiliation: †Department of Applied Chemistry, China Agricultural University, Beijing 100193, People's Republic of China.
authors.forename: Donghui
authors.initials: D
authors.lastname: Liu
authors.affiliation: ‡Chinese People's Armed Police Force Academy, Langfang 065000, People's Republic of China.
authors.forename: Yangguang
authors.initials: Y
authors.lastname: Xu
authors.affiliation: †Department of Applied Chemistry, China Agricultural University, Beijing 100193, People's Republic of China.
authors.forename: Xu
authors.initials: X
authors.lastname: Jing
authors.affiliation: †Department of Applied Chemistry, China Agricultural University, Beijing 100193, People's Republic of China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: †Department of Applied Chemistry, China Agricultural University, Beijing 100193, People's Republic of China.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
mesh_terms: D000409:Alanine / Q000031:analogs & derivatives* / Q000737:chemistry; D005659:Fungicides, Industrial / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry*; D007700:Kinetics; D013237:Stereoisomerism; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D005659:Fungicides, Industrial; D014874:Water Pollutants, Chemical; D014867:Water; C052866:benalaxyl; D000409:Alanine
keywords: benalaxyl; contamination; stereoselectivity; water−sediment microcosm