Ecotoxicity of Mine Tailings: Unrehabilitated Versus Rehabilitated
Earthworms are bioindicators of soil pollution. The ecotoxicity of tailings from selected gold mines in South Africa was investigated utilizing Eisenia andrei bioassays and biomarkers. Samples were obtained from unrehabilitated, rehabilitated and naturally vegetated sites. Biomass, neutral red retention time (NRRT), survival and reproduction were assessed using standardized protocols. Earthworm biomass, NRRT and reproductive success in rehabilitated tailings (comparable to naturally vegetated site) were significantly higher (p < 0.05) than in unrehabilitated tailings. In addition, significantly lower (p < 0.05) body tissue concentrations of As, Cd, Co, Cu and Ni contents were found in the rehabilitated tailings compared to the unrehabilitated. Further, significantly lower (p < 0.05) soil Mn and Zn concentrations were obtained in unrehabilitated tailings than the rehabilitated and naturally vegetated sites. Overall, reduced ecotoxicity effects were confirmed in rehabilitated compared to unrehabilitated tailings. This suggests that rehabilitation as a post-mining restorative strategy has strong positive influence on mine tailings.
KeywordsBiomarkers Eisenia andrei Gold mine tailings Soil pollution Rehabilitated and unrehabilitated sites Post-mining restoration strategy
The financial assistance of the National Research Foundation (NRF) towards this research is hereby acknowledged. Opinions expressed and conclusions arrived at, are those of the authors and are not necessarily to be attributed to the NRF.
Compliance with Ethical Standards
Conflict of interest
We hereby declare that the research has no possible conflicts of interest and that animals (earthworms) used in this study was handled according to ethical compliant standards.
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