title: Enantioselective bioaccumulation and toxic effects of metalaxyl in earthworm Eisenia foetida.
abstract: Knowledge about the enantioselective bioavailability of chiral pesticides in soil invertebrates facilitates more accurate interpretation of their environmental behaviors. In this study, the acute toxicities of R-metalaxyl and rac-metalaxyl to earthworm (Eisenia foetida) were assayed by filter paper contact test. After 48 h of exposure, the calculated LC(50) values for R- and rac-metalaxyl were 0.052 and 0.022 mg cm(-2), respectively, resulting in a two fold difference in toxicity. For uptake experiment, earthworms were exposed in soil at two dose levels (10 and 50 mg kg(dwt)(-1)). The concentrations of two enantiomers in soil and earthworm were determined by high-performance liquid chromatography based on cellulose tri-(3,5-dimethylphenyl-carbamate) chiral stationary phase. The results showed that metalaxyl was taken up by earthworm rapidly, and the bioaccumulation of metalaxyl in earthworm was enantioselective with preferential accumulation of S-enantiomer. In addition, biota to soil accumulation factor (BSAF) used to express the bioaccumulation of metalaxyl enantiomers was investigated, and significant difference was observed between rac-metalaxyl and R-metalaxyl.
authors.affiliation: Department of Applied Chemistry, China Agricultural University, Beijing 100193, PR China.
authors.forename: Peng
authors.initials: P
authors.lastname: Xu
authors.forename: Jinling
authors.initials: J
authors.lastname: Diao
authors.forename: Donghui
authors.initials: D
authors.lastname: Liu
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D000409:Alanine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics / Q000633:toxicity; D000818:Animals; D001682:Biological Availability; D005659:Fungicides, Industrial / Q000493:pharmacokinetics / Q000633:toxicity*; D008968:Molecular Conformation; D009835:Oligochaeta / Q000187:drug effects* / Q000378:metabolism; D012987:Soil / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D005659:Fungicides, Industrial; D012987:Soil; C028175:metalaxyl; D000409:Alanine