Ecotoxicological assessment of cobalt used as supplement in the diet of common carp Cyprinus carpio.

摘要

Experiments were performed in the laboratory to determine if excess levels of Co used as dietary supplement (0.0, 0.05, 0.10 and 1.0%) to enhance growth of the fish Cyprinus carpio was safe for aquatic organisms. Lethal concentrations of Co for tadpole of toad Bufo melanostictus (96 h LC₅₀, 17.2 mg/L), oligochaet worm Branchiura sowerbyi (96 h LC₅₀, 179 mg/L) and crustacean zooplankton Diaptomus forbesi (96 h LC₅₀, 1.5 mg/L) were compared with the concentration of Co in the medium leached from the unused diets and faeces. The results indicated that the Co leached from diet containing 1.0% Co was ecotoxicologically unsafe for crustacean zooplankton.