Cocoon production and viability as endpoints in toxicity testing of heavy metals with three earthworm species

Abstract

Summary This study compares the cocoon production and cocoon viability of three earthworm species, Eudrilus eugeniae, Perionyx excavatus and Eisenia fetida after exposure to a sublethal concentration of lead nitrate. Cocoon production in all three species did not differ significantly between exposed and control worms. However, cocoon viability in all three species was affected detrimentally by the presence of lead nitrate. Cocoons of Eisenia fetida from substrates contaminated by lead nitrate, cadmium sulphate and zinc sulphate for 36 months, also showed a lowered cocoon viability. It is concluded that cocoon viability may be a sensitive endpoint of sublethal toxicity of these metal salts.