Chlordecone retention in the fractal structure of volcanic clay.

Thierry Woignier, Florence Clostre, Hervé Macarie, Magalie Jannoyer

IRD, UMR 237, IMBE, PRAM B.P. 214 Petit Morne, 97232, Le Lamentin, Martinique. thierry.woignier@imbe.fr

Journal of hazardous materials 2012 Nov 30

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Chlordecone (CHLD), a soil and foodstuff pollutant, as well as an environmentally persistent organochlorine insecticide, was used intensively in banana fields. The chlordecone uptake of three crops was measured for two types of polluted soils: allophanic and non-allophanic. The uptake is lower for allophanic soils even if their chlordecone content is higher than with non-allophanic soils. The fractal structure of the allophane aggregates was characterized at the nanoscale by small angle X-rays scattering, pore size distribution and transmission electron microscopy. We showed that clay microstructures should be an important physico-chemical factor governing the fate of chlordecone in the environment. Allophanic clays result in two counterintuitive findings: higher contaminant trappings yet lower contaminant availability. We propose that this specific, tortuous structure, along with its associated low accessibility, partly explains the low availability of chlordecone confined in allophanic soils. Capsule The fractal and tortuous microstructure of allophane clay favours the chlordecone retention in soils and disfavours the crop uptake. Copyright © 2012 Elsevier B.V. All rights reserved.

Citation

Thierry Woignier, Florence Clostre, Hervé Macarie, Magalie Jannoyer. Chlordecone retention in the fractal structure of volcanic clay. Journal of hazardous materials. 2012 Nov 30;241-242:224-30