Ecotoxicity of mercury to Eisenia fetida, Enchytraeus albidus and Folsomia candida

Despite growing concerns about the potential adverse effects of elevated mercury concentrations in the environment, only a few toxicity data are available for soil invertebrates. The chronic toxicity of mercury (II) was therefore assessed for Eisenia fetida, Enchytraeus albidus and Folsomia candida using standard test protocols. The 21-day EC₅₀ (the concentration causing 50% effect) for the cocoon production of E. fetida was 9.16 mg Hg kg^-1 dry wt. Based on the reproduction, a 42-day EC₅₀ of 22.0 mg Hg kg^-1 dry wt was observed for E. albidus while for F. candida the 28-day EC₅₀ was 3.26 (2.45-4.05) mg Hg kg^-1 dry wt. Although these data can be considered as a step forward in the assessment of the potential risks of mercury in terrestrial environments, further research is needed to evaluate the influence of soil parameters on the toxicity of mercury and to quantify the effect of ageing on the bioavailability.