Heavy metal accumulation by Eisenia fetida and its effects on glutathione-S-transferase activity

Bioaccumulation of cadmium, zinc and lead by Eisenia fetida typica exposed to five contaminated field soils was studied. Worms regulate zinc burdens but not cadmium or lead. No linear regression was found relating worm cadmium burdens to total amount in soils, most likely due to differences of bioavailability. Ammonium acetate, calcium chloride and water extraction techniques of heavy metals from soils were tested and related to worm burdens. Except for zinc, which is more closely related to less drastic extraction techniques, total soil content of metal seems to be the most interesting to relate worm heavy metal burdens. Moreover, the effects of cadmium, zinc, lead, and copper chloride on worm glutathione-S-transferase activities were studied in vitro and in vivo. GST activity appears not to be affected by heavy metal bioaccumulation as no statistically significant effects were observed neither in vivo nor in vitro on total GST activity.