The remediation of metal-impacted soils requires either the enhanced mobility (and capture) of the target analytes or their effective complexation/immobilisation. In this study, a range of ameliorants (activated carbon, bonemeal, bentonite and CaSx (calcium polysulphide)) were compared to assess their effectiveness in immobilising metals in soils. In addition to chemical analysis (pH and trace element analysis), microbial biosensors were used to assess changes in the water-soluble biotoxicity of metals as a consequence of ameliorant dosing. Management of soil ameliorants requires an enhancement of K d (solid/solution partition coefficient) if soil leachate is to meet predefined environmental quality standards. Of the ameliorants tested, CaSx was the most effective per unit added for both laboratory-amended and historically contaminated soils, regardless of the metal tested. At the ameliorant concentrations used to effectively immobilise the metals, the biosensor performance was not impaired. Microbial biosensors offered a rapid and relevant screening tool to validate the reduced toxicity associated with the ameliorant dosing and could be calibrated to complement chemical analysis. While laboratory-amended soils were a logical way to evaluate the performance of the ameliorants, they were generally associated with K d values an order of magnitude lower than those of historically contaminated soils.
SPM and MAW acknowledge European funding for FP6 project no. 043741, SD acknowledges funding from the University of Dammam, Kingdom of Saudi Arabia. EED acknowledges funding from EPSRC and Remedios Limited, Aberdeen.
- Biosensor analysis
- Heavy metals
- K d value
- Soil ameliorants
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- Biological Sciences, Aberdeen Centre For Environmental Sustainability - Head of School of Biological Sciences, Chair in Biological Sciences
- Engineering, National Decommissioning Centre
- Centre for Energy Transition
- Marine Alliance for Science and Technology for Scotland (MASTS)