Enantioselective Acute Toxicity Effects and Bioaccumulation of Furalaxyl in the Earthworm (Eisenia foetida)

The enantioselectivities of individual enantiomers of furalaxyl in acute toxicity and bioaccumulation in the earthworm (Eisenia foetida) were studied. The acute toxicity was tested by filter paper contact test. After 48 h of exposure, the calculated LC₅₀ values of the R‐form, rac‐form, and S‐form were 2.27, 2.08, and 1.22 µg cm^‐2, respectively. After 72 h of exposure, the calculated LC₅₀ values were 1.90, 1.54, and 1.00 µg cm^‐2, respectively. Therefore, the acute toxicity of furalaxyl enantiomers was enantioselective. During the bioaccumulation experiment, the enantiomer fraction of furalaxyl in earthworm tissue was observed to deviate from 0.50 and maintained a range of 0.55–0.60; in other words, the bioaccumulation of furalaxyl was enantioselective in earthworm tissue with a preferential accumulation of S‐furalaxyl. The uptake kinetic of furalaxyl enantiomers fitted the first‐order kinetics well and the calculated kinetic parameters were consistent with the low accumulation efficiency. Chirality 26:307–312, 2014. © 2014 Wiley Periodicals, Inc.