Contamination of grazing ducks by chlordecone in Martinique

Chlordecone (CLD) is an organochlorine pesticide used from 1971 to 1993 in French West Indies to fight against banana black weevil. The former application of this insecticide has resulted in long-term pollution of soils and in subsequent contamination of local waters and food resources. In this area, grazing poultry may be used to control weeds in orchards as an alternative to herbicides. However, CLD may be transferred into animal products through polluted soil ingestion. The question arises whether these grazing ducks may be consumed by the farmers, i.e. whether the concentration of CLD complies with the legal 20 ?g/kg maximum residue limit (MRL). Muscovy ducks were raised on a guava orchard planted on a soil moderately contaminated (0.4 mg CLD/kg DM). Ducks were raised indoor up to 6 weeks of age and allowed to graze thereafter. Thirty-two females were sequentially slaughtered by groups of 3 or 4 ducks, either after a 4-, 16-, 19-, 22- or 26-week grazing period or after a 16-week grazing period followed by a 3-, 6- or 9-week decontamination period. During decontamination, ducks were raised indoor without any contact with the environment. After 4 weeks grazing, CLD concentrations in liver and in meat (leg with skin) were 258 and 60 ?g/kg, respectively, already far over the MRL. These values increased with time to reach 1051 and 169 ?g/kg, respectively, after 22-week grazing and remained steady thereafter. Ducks kept indoor gradually decontaminated with concentrations reduced down to 47 and 6 ?g/kg, respectively, after 9 weeks. According to this decontamination curve, the time required for decontamination down to the MRL was estimated at 83 and 41 days in liver and in meat, respectively. Thus, the consumption of products from these ducks, especially liver, should be avoided, unless grazing and decontamination practices are improved. (Résumé d'auteur