Is a dissipation half-life of 5 years for chlordecone in soils of the French West Indies relevant?

• Published in: Environmental pollution (1987) 2023-05, Vol.324, p.121283-121283, Article 121283
• Main Authors: Saaidi, Pierre-Loïc, Grünberger, Olivier, Samouëlian, Anatja, Le Roux, Yves, Richard, Antoine, Devault, Damien A., Feidt, Cyril, Benoit, Pierre, Evrard, Olivier, Imfeld, Gwenaël, Mouvet, Christophe, Voltz, Marc
• Format: Article
• Language: English
• Subjects: Biodiversity and Ecology; Chemical Sciences; Chlordecone; Chlordecone - analysis; Chlordecone - metabolism; Dissipation; Environmental fate; Environmental Sciences; Half-Life; Insecticides - analysis; Modeling; Other; Persistent organic pollutants; Soil; Soil Pollutants - analysis; Soils; West Indies
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2023.121283

Recently, Comte et al. (2022) re-examined the natural degradation of chlordecone (CLD) in the soils of the French West Indies (FWI) by introducing an additional ‘dissipation parameter’ into the WISORCH model developed by Cabidoche et al. (2009). Recent data sets of CLD concentrations in FWI soils obtained by Comte et al. enabled them optimizing the model parameters, resulting in significantly shorter estimates of pollution persistence than in the original model. Their conclusions jeopardize the paradigm of a very limited degradation of CLD in FWI soils, which may lead to an entire revision of the management of CLD contamination. However, we believe that their study is questionable on several important aspects. This includes potential biases in the data sets and in the modeling approach. It results in an inconsistency between the estimated dissipation half-life time (DT50) of five years that the authors determined for CLD and the fate of CLD in soil from the application period 1972–1993 until nowadays. Most importantly, a rapid dissipation of CLD in the field as proposed by Comte et al. is not sufficiently supported by data and estimates. Hence, the paradigm of long-term persistence of CLD in FWI soils is still to be considered. [Display omitted] •The marked apparent decrease of chlordecone in Guadeloupe soils is questionable.•The dataset by Comte et al. (2022) is not suitable for optimizing a predictive model.•A dissipation half-life of 5 years for chlordecone in FWI soils is not realistic.•The long-term persistence of Chlordecone should remain the most likely hypothesis.