Effects of leaching from alkaline red mud on soil biota: modelling the conditions after the Hungarian red mud disaster

• Published in: Chemistry and ecology Vol. 29; no. 8; pp. 709 - 723
• Main Authors: Rékási, Márk, Feigl, Viktória, Uzinger, Nikolett, Gruiz, Katalin, Makó, András, Anton, Attila
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 01.11.2013; Taylor & Francis Ltd
• Subjects: Animal, plant and microbial ecology; Applied ecology; bauxite residue; Biological and medical sciences; ecotoxicology test; Ecotoxicology, biological effects of pollution; element fractions; Environmental impact; Folsomia candida; Fundamental and applied biological sciences. Psychology; General aspects; General aspects. Techniques; heavy metals; Leaching; Methods and techniques (sampling, tagging, trapping, modelling...); Native peoples; Sinapis alba; Vibrio fischeri; Hungary; Eastern Europe; Europe; element fractions; Ecotoxicology; heavy metals; Biota; ecotoxicology test; Disaster; bauxite residue; Leaching; Modeling; Ooze; Heavy metal; Soils; Biocenosis; Residue; Mud
• ISSN: 0275-7540; 1029-0370
• DOI: 10.1080/02757540.2013.817568

A soil column experiment was set up to investigate the effect of red mud from Ajka (Hungary) on a typical soil profile from the affected area. The chemical changes caused by the red mud leachate and the effects of these changes on living organisms were assessed. Ecotoxicological tests were performed with Vibrio fischeri, Sinapis alba and Folsomia candida and the number of aerobic heterotrophic microorganisms was determined. The total, plant-available, exchangeable and water-soluble fractions of Na, Mo, Cu and Cr increased in the soil, mostly owing to their leaching from the red mud layer, but partly to the increase in the pH and DOC concentration. The chemical changes only had significant effects on the test organisms in the 0-30 cm soil layer, except for F. candida, which also had a lower survival rate in the 30-50 cm soil layer. No severe toxic effects were detected in the test organisms; in fact a stimulating effect was revealed for the aerobic heterotrophic cell number and for S. alba germination. However, the red mud itself was toxic, so the ecotoxicological tests justified the removal of red mud from the soil surface after the disaster.