Acute toxicities and preliminary risk evaluation of chiral ethiprole to three non-target organisms

Ethiprole has been registered as an alternative pesticide of fipronil and widely promoted in China, but its toxicity to environmentally beneficial organisms has rarely been reported. In this study, the acute toxicities of racemic ethiprole and the corresponding enantiomers to Apis mellifera L., Bombyx mori and Eisenia foetida were investigated by the standard topical application method, intake poisonous leaf method and filter paper residue method, and the preliminary risk evaluation was carried out. Results showed that the 48 h-LD50 of racemic ethiprole, S-(+)-ethiprole and R-(-)-ethiprole to A. mellifera were 0.018 7, 0.018 1 and 0.018 8 μg/bee, respectively. The 96 h-LC50 of racemic ethiprole, S-(+)-ethiprole and R-(-)-ethiprole to B. mori were 66.9, 63.7 and 70.3 mg/L, respectively. And the 48 h-LR50 of racemic ethiprole, S-(+)-ethiprole and R-(-)-ethiprole to E. foetida were 511, 488 and 547 μg/cm2, respectively. The study showed that ethiprole was of high risk to A. mellifera, pollution. It should be avoided to apply the pesticide during the flowering period. Besides, no obvious enantio-selectivity was observed for acute toxicity to these three kinds of non-target organisms. So it is impossible to reduce the risks to bees, silkworms and earthworm by the application of the corresponding single enantiomer.