Effects of soil properties and aging process on the acute toxicity of cadmium to earthworm Eisenia fetida

Abstract

This study was undertaken to investigate the effects of soil properties and aging process on the acute toxicity of cadmium (Cd) to Eisenia fetida (E. fetida) in 18 Cd-spiked soils. Results showed that the Cd toxicity to E. fetida differed in the 18 soils with different characteristics, and median lethal concentration (LC50) values varied from 440.7 to 1520.4 mg/kg in freshly spiked soils. Soil pH and organic matter (OM) content were the two major factors associated with Cd toxicity. The increase in LC50 values and decreases in both exchangeable Cd in soils and tissue Cd concentrations in earthworm whole body indicated that aging (180 and 360 days) could reduce the acute toxicity and bioavailability of Cd to E. fetida. Cadmium concentrations in E. fetida were positively correlated with exchangeable Cd content in soils, and soil pH and OM were the key factors controlling the distribution and transformation of the exchangeable Cd. The results will provide useful reference information for the risk assessment of Cd in the terrestrial environment.

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