title: Natural transformation of chlordecone into 5b-hydrochlordecone in French West Indies soils: statistical evidence for investigating long-term persistence of organic pollutants.
abstract: Chlordecone (CLD) was an organochlorine insecticide whose previous use resulted in an extensive pollution of the environment with severe health effects and social consequences. A closely related compound, 5b-hydrochlordecone (5b-hydroCLD), has been searched for and often detected in environmental matrices from the geographical area where CLD was applied. The current consensus considered that its presence was not the result of a biotic or abiotic dechlorination of CLD in these matrices but rather the consequence of its presence as impurity (synthesis by-product) in the CLD released into the environment. The aim of the present study was to determine if and to what extent degradation of CLD into 5b-hydroCLD occurred in the field. To test this hypothesis, the ratios of 5b-hydroCLD and CLD concentrations in a dataset of 810 soils collected between 2006 and 2012 in Martinique were compared to the ratios measured in 3 samples of the CLD dust commercial formulations applied in the banana fields of French West Indies (FWI) and 1 sample of the technical-grade CLD corresponding to the active ingredient used in such formulations. Soil data were processed with a hierarchical Bayesian model to account for random measurement errors and data censoring. Any pathway of CLD transformation into 5b-hydroCLD occurring over the long term in FWI soils would indeed change the ratio of 5b-hydroCLD/CLD compared to what it was in the initially applied formulations. Results showed a significant increase of the 5b-hydroCLD/CLD ratio in the soils-25 times greater in soil than in commercial formulations-which suggested that natural CLD transformation into 5b-hydroCLD over the long term occurred in these soils. Results from this study may impact future decisions for the remediation of the polluted areas.
authors.affiliation: EA 929 AIHP-GEODE, Groupe Biospheres, Université des Antilles, Campus de Schœlcher, Schœlcher Cedex, France. damien.devault@martinique.univ-ag.fr.|Faculté de Pharmacie, UMR 8079, CNRS AgroParisTech, Univ. Paris Sud, 75005, Paris, France. damien.devault@martinique.univ-ag.fr.
authors.forename: Damien A
authors.initials: DA
authors.lastname: Devault
authors.affiliation: INP, UPS, CNRS, ECOLAB (Laboratoire Ecologie Fonctionnelle et Environnement), ENSAT, Université de Toulouse, Avenue de l'Agrobiopole, 31326, Castanet Tolosan, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Laplanche
authors.affiliation: EA 929 AIHP-GEODE, Groupe Biospheres, Université des Antilles, Campus de Schœlcher, Schœlcher Cedex, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Pascaline
authors.affiliation: Division Laboratoires, BRGM, 3 Avenue Claude Guillemin, BP6009, 45060, Orléans Cedex, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Bristeau
authors.affiliation: Division Eau, Environnement et Ecotechnologies, BRGM, 3 avenue Claude Guillemin, BP6009, 45060, Orléans Cedex, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Mouvet
authors.affiliation: IRD, UMR IMBE, Campus Agro-environnemental Caraïbe, BP 214, 97285, Lamentin, France.|Aix Marseille Université, CNRS, IRD, Avignon Université, IMBE, UMR 7263 - IRD 237, 13397, Marseille, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Macarie
mesh_terms: D001499:Bayes Theorem; D001673:Biodegradation, Environmental; D007631:Chlordecone / Q000031:analogs & derivatives* / Q000378:metabolism*; D006801:Humans; D007306:Insecticides / Q000378:metabolism*; D008395:Martinique; D028521:Musa; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000378:metabolism*; D013995:Time; D014900:West Indies
chemical_list: C000609891:5b-hydrochlordecone; D007306:Insecticides; D012987:Soil; D012989:Soil Pollutants; D007631:Chlordecone
keywords: Banana; Curlone; Data censoring; Hierarchical Bayesian modelling; Kepone; Martinique; Pesticides