Selective bioaccumulation of neonicotinoids and sub-lethal effects in the earthworm Eisenia andrei exposed to...

In this study, we evaluated the bioaccumulation of neonicotinoid insecticides in the earthworm Eisenia andrei exposed to environmental concentrations (<200 ng g^-1 dry weight, nominal concentration) in an artificial soil. We tested the selectivity for neonicotinoids by exposing earthworms to 7 neonicotinoids alone and in more complex mixtures of 54 pesticides then 69 organic contaminants (OCs) (54 pesticides and 15 pharmaceuticals). We applied long-term (56-day) toxicity tests to further evaluate the effect of OCs on earthworms. We monitored adult survival, adult DNA damage using a comet assay on earthworm coelomocyte cells, and reproduction performance (i.e. number of cocoons and number and dry weight of juveniles). A selective bioaccumulation of neonicotinoid insecticides in adult and juvenile earthworms was found. This bioaccumulation is concomitant with a significant increase in adult DNA damage and significant effects on reproduction when earthworms were exposed to neonicotinoid insecticides alone. This study reveals a new potential point of entry of neonicotinoid insecticides into the wildlife food chain and also shows that E. andrei reproduction could be affected by long-term exposure to environmental concentrations of OCs.