Enantioselective acute toxicity and bioaccumulation of benalaxyl in earthworm (Eisenia fedtia).
The enantioselectivities of individual enantiomers of benalaxyl in acute toxicity and bioaccumulation in earthworm ( Eisenia fedtia ) were studied. The acute toxicity was tested by paper contact test. After 48 h of exposure, the calculated LC(50) values of the R-(-)-form, rac-form, and S-(+)-form were 4.99, 5.08, and 6.66 microg/cm(2), respectively. After 72 h of exposure, the calculated LC(50) values were 1.23, 1.73, and 2.45 microg/cm(2), respectively. Therefore, the acute toxicity of benalaxyl enantiomers was enantioselective. A method for determining residues of the two enantiomers of benalaxyl in earthworm tissue by high-performance liquid chromatography based on cellulose tri-(3,5-dimethylphenyl-carbamate) chiral stationary phase was developed. During the bioaccumulation experiment, the enantiomer fraction in earthworm tissue was maintained approximately at 0.6, whereas enantiomer fraction in spiked soil was maintained at 0.5; in other words, the bioaccumulation of benalaxyl was enantioselective in earthworm tissue. Peak-shaped accumulation curves were observed for both enantiomers, and the calculated biota to soil accumulations (kg dry kg(-1) wet weight) at steady state were below 1 for both enantiomers. During the elimination experiment, 79.0% of R-(-)-enantiomer and 89.6% of S-(+)-enantiomer in earthworm tissue were eliminated within 2 days.
Xu
Peng
P
Department of Applied Chemistry, China Agricultural University, Beijing 100193, China.
Liu
Donghui
D
Diao
Jinling
J
Lu
Dahai
D
Zhou
Zhiqiang
Z
D000409:Alanine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism / Q000633:toxicity; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D007928:Lethal Dose 50; D009835:Oligochaeta / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism*; D012987:Soil / Q000032:analysis; D013237:Stereoisomerism
D012987:Soil; C052866:benalaxyl; D000409:Alanine