Assessments of the impact of metals on juvenile earthworms (Eisenia fetida) in laboratory conditions

The aim of this study was to evaluate the impact of different concentrations of copper and zinc on the mortality and bodyweight of juvenile earthworms in artificial soil. Copper was more toxic with complete mortality at the dose rate of 1000 mg/kg. Bodyweight loss of earthworms was observed immediately, after the first week, except at the lowest concentration. In comparison to control, there were significant differences in the bodyweight loss every week in the concentrations of 333 and 666 mg/kg, and also 167 mg/kg in the fourth, sixth, and eighth week. Zinc has not shown a significant effect on mortality, except in the highest concentration, where survival was less than 25%. Statistically significant effect (p < 0.05) on bodyweight was registered only at the highest concentration, every week. The impact of metals on earthworm populations should be more accurately assessed, and data for juvenile earthworms should be considered when proposing a safe concentration of pollutants in the environment, because of the great importance of these animals' presence in the soil.