Effects of bifenthrin exposure in soil on whole-organism endpoints and biomarkers of earthworm Eisenia fetida

- The toxicity of bifenthrin to E. fetida in soil was evaluated synchronously by multi-endpoints in different levels.
- Bifenthrin was low toxic in soil but its reproduction toxicity was demonstrated.
- EROD activity in earthworm was measured by HPLC and used as a biomarker to assess the effects of bifenthrin.
- The toxicity response of worms to the reduced bifenthrin in content, demonstrated the formation of toxic metabolites.

In this study, toxic effects of bifenthrin in soil on earthworms were evaluated by acute and chronic toxic endpoints combined with a set of biomarkers. Bifenthrin was moderately toxic in 72-h filter paper test and low toxic in 14-d soil test. The exposure of earthworms to bifenthrin-polluted soil for 8 weeks showed that cocoons were inhibited by high dose of bifenthrin, and larvae were stimulated by low dose but inhibited by high dose of bifenthrin. Furthermore, 28-d soil test on the responses of enzymes associated with antioxidation and detoxification in worms showed that peroxidase (POD) was stimulated by bifenthrin, superoxide dismutase (SOD) inhibited in the early period but stimulated in the later period, glutathione S- transferase (GST) inhibited in the later period, and ethoxyresorufin-O-deethylase (EROD) inhibited at day 3 but markedly stimulated at day 28 at high dose. The different responses of these indexes indicated that multi indexes should be jointly taken into account for comprehensive evaluation of the environmental risk of contaminants in soil.