Accumulation and elimination of cadmium, chromium and zinc and effects on growth and reproduction in Eisenia andrei (Oligochaeta, Annelida)

Abstract

Accumulation and elimination of cadmium, chromium and zinc and effects on the growth and reproduction of the earthworm Eisenia andrei were determined in an artificial soil. Cadmium at the lowest soil concentration tested (10 mg/kg) significantly reduced cocoon production, whereas cadmium concentrations in the earthworms at the end of the 3-week exposure period were significantly increased in a dose-related manner at all concentrations tested. Reproduction was completely recovered at the end of a 3-week recovery period in untreated soil, although cadmium concentrations in the earthworms were still significantly elevated. Apparently, the remaining cadmium residues in the worms were strongly bound, and therefore no longer exerted a toxic effect on the reproduction of earthworms. Chromium was significantly accumulated and earthworm reproduction significantly reduced at soil concentrations of 100 mg/kg and higher. Chromium was completely eliminated and reproduction no longer affected at the end of a 3-week recovery period. Zinc significantly reduced reproduction at soil concentrations of 560 and 1000 mg/kg, and induced the production of malformed cocoons. Earthworms were able to regulate their body content of zinc; only at 1000 mg/kg dry soil were zinc concentrations significantly increased. At the end of a 3-week recovery period zinc concentrations in the earthworms had returned to the control level, and reproduction was completely recovered.