title: Linking current river pollution to historical pesticide use: Insights for territorial management?
abstract: Persistent organic pollutants like organochlorine pesticides continue to contaminate large areas worldwide raising questions concerning their management. We designed and tested a method to link soil and water pollution in the watershed of the Galion River in Martinique. We first estimated the risk of soil contamination by chlordecone by referring to past use of land for banana cultivation and took 27 soil samples. We then sampled surface waters at 39 points and groundwater at 16 points. We tested three hypotheses linked to the source of chlordecone pollution at the watershed scale: (i) soils close to the river, (ii) soils close to the sampling point, (iii) throughout the sub-watershed generated at the sampling point. Graphical and statistical analysis showed that contamination of the river increased when it passed through an area with contaminated plots and decreased when it passed through area not contaminated by chlordecone. Modeling showed that the entire surface area of the watershed contributed to river pollution, suggesting that the river was mainly being contaminated by the aquifers and groundwater flows. Our method proved to be a reliable way to identify areas polluted by chlordecone at the watershed scale and should help stakeholders focus their management actions on both hot spots and the whole watershed.
authors.affiliation: Cirad, UPR HortSys, F-97285 Le Lamentin, Martinique, France. Electronic address: pauline.della_rossa@cirad.fr.
authors.forename: Pauline
authors.initials: P
authors.lastname: Della Rossa
authors.affiliation: Cirad, UPR HortSys, F-97285 Le Lamentin, Martinique, France. Electronic address: magalie.jannoyer@cirad.fr.
authors.forename: Magalie
authors.initials: M
authors.lastname: Jannoyer
authors.affiliation: Cirad, UPR HortSys, F-97285 Le Lamentin, Martinique, France. Electronic address: charles.mottes@cirad.fr.
authors.forename: Charles
authors.initials: C
authors.lastname: Mottes
authors.affiliation: Cirad, UPR HortSys, F-97285 Le Lamentin, Martinique, France. Electronic address: joanne.plet@cirad.fr.
authors.forename: Joanne
authors.initials: J
authors.lastname: Plet
authors.affiliation: Cirad, UPR HortSys, F-97285 Le Lamentin, Martinique, France. Electronic address: abderazak.bazizi@cirad.fr.
authors.forename: Abderazak
authors.initials: A
authors.lastname: Bazizi
authors.affiliation: BRGM Martinique, F-97200 Fort-de-France, Martinique, France. Electronic address: l.arnaud@brgm.fr.
authors.forename: Luc
authors.initials: L
authors.lastname: Arnaud
authors.affiliation: Cirad, UPR HortSys, F-97285 Le Lamentin, Martinique, France. Electronic address: alexandra.jestin@cirad.fr.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Jestin
authors.affiliation: CNRS, UMR 7263 IMBE, F-97285 Le Lamentin, Martinique, France; IRD, UMR 237 IMBE, F-97285 Le Lamentin, Martinique, France; Aix Marseille Univ, Univ Avignon, CNRS, IRD, IMBE, F-13331 Marseille, France. Electronic address: woignier@diablo.univ-montp2.fr.
authors.forename: Thierry
authors.initials: T
authors.lastname: Woignier
authors.affiliation: Cirad, UPR HortSys, F-97285 Le Lamentin, Martinique, France. Electronic address: jean-marie.gaude@cirad.fr.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Gaude
authors.affiliation: Cirad, UPR GECO, F-97130 Capesterre-Belle-Eau, Guadeloupe, France. Electronic address: philippe.cattan@cirad.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Cattan
keywords: Catchment; Chlordecone; Modeling; Past pesticide use; Spatial variability; Water pollution