Natural transformation of chlordecone into 5b-hydrochlordecone in French West Indies soils : statistical evidence for investigating long-term persistence of organic pollutants

2016

Article référencé dans le Web of Science WOS:000368199300010

Devault D. A., Laplanche C., Pascaline H., Bristeau S., Mouvet C., Macarie Hervé

Devault D.A. (ed.), Macarie Hervé (ed.), Lemoine S. (ed.), Crop protection and environmental health : legacy management and new concepts

Environmental Science and Pollution Research, 2016, 23 (1), p. 81-97 ISSN 0944-1344

Colloque Annuel du Groupement Français des Pesticides (GFP), 44., Fort-de-France (MTQ), 2014/05/26-29

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.

Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Pollution [038] ; Pédologie [068] ; Sciences du monde végétal [076]

MARTINIQUE

Fonds IRD [F A010066624]

fdi:010066130