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Chlordecone (CLD), was widely applied in banana fields in the French West Indies from 1972 to 1993. The WISORCH model was constructed to assess soil contamination by CLD and estimated that it lasts from 100 to 600 years, depending on leaching intensity and assuming no degradation. However, recent studies demonstrated that CLD is degraded in the environment, hence questioning the reliability of previous estimations. This paper shows how to improve the model and provides insights into the long-term dissipation of CLD. In-situ observations were made in nearly 2545 plots between 2001 and 2020, and 17 plots were sampled at two dates. Results of soil analyses showed an unexpected 4-fold decrease in CLD concentrations in the soil, in contrast to simulations made using the first version of WISORCH at the time. Neither erosion, nor CLD leaching explained these discrepancies. In a top-down modeling approach, these new observations of CLD concentrations led us to implement a new dissipation process in the WISORCH model that corresponds to a DT50 dissipation half-life of 5 years. The new version of the improved model allowed us to update the prediction of the persistence of soil pollution, with soil decontamination estimated for the 2070s. This development calls for re-evaluation of soil pollution status. Further validation of the new version of WISORCH is needed so it can contribute to crop management on contaminated soil. [Display omitted] • Chlordecone (CLD) pollution in FWI was previously estimated to last for centuries. • Field observations improved CLD modeling in a top-down modeling approach. • a DT50 of 5 years allowed us to simulate the observed decrease of CLD in soils. • With this unexpected decrease rate, soil decontamination is forecast for the 2070s. • This calls for re-evaluation of soil pollution status, not envisaged until now. [ABSTRACT FROM AUTHOR]

The article discusses ways in which the nematicide cadusafos contaminates water and soils within subcatchments and catchments. A study to determine ecological impact was sited at a small banana-growing catchment on the volcanic island of Guadeloupe located in the Caribbean. Researchers monitored the surface water and groundwater flows and the cadusafos concentrations in the soil and waters of a selected subcatchment and catchment. It was found that high retention within the A horizon of soils limits the transports of nematicides by runoff, whereas the B horizon offers lower retention of the molecule and favors percolation toward the shallow groundwater.

In Guadeloupe, the use between 1972 and 1993 of chlordecone, an organochlorine insecticide, has permanently contaminated the island's soil, thus contaminating the food chain at its very beginning. There is today a strong societal requirement for an improved mapping of the contaminated zones. Given the extent of the areas to be covered, carrying out soil tests on each plot of the territory would be a long and expensive process. In this article, we explore a method of demarcating polluted areas. The approach adopted consists in carrying out, using surface water analyses, a hydrological delimitation that makes it possible to distinguish contaminated watersheds from uncontaminated ones. The selection of sampling points was based on the spatial analysis of the actual and potential contamination data existing at the beginning of the study. The approach was validated by soil analyses, after having compared the contamination data of the watersheds with the soil contamination data of the plots within them. The study thus made it possible to highlight new contaminated areas and also those at risk of contamination and to identify the plots to be targeted as a priority during future analysis campaigns by State services.