The former use of chlordecone (CLD) in the French West Indies has resulted in long-term pollution of soils and of food chains. CLD may be transferred into eggs of hens reared outdoors, through polluted soil ingestion. Tropical volcanic soils display variable capacities of pollutant retention: CLD is less available and more persistent in andosol than in nitisol. The impact of soil type on CLD bioavailability to hens was tested through a relative bioavailability study. The deposition of CLD in egg yolk and in abdominal fat was measured in 42 individually housed laying hens fed with diets containing graded levels of CLD from polluted andosol, nitisol, or spiked oil during 23 days. Within each ingested matrix, the concentration of CLD in yolk and in abdominal fat linearly increased with the amount of ingested CLD (P < 0.001). However, the response to andosol diets and to nitisol diets was not different from the response to oil diets (P > 0.1), indicating that CLD was equally bioavailable to laying hens, irrespective of the matrix. This suggests that the hen's gastrointestinal tract efficiently extracts CLD from the two tropical volcanic soils, regardless of their retention capacity. Thus, hens reared on polluted soils with CLD may lay contaminated eggs.

The application of chlordecone (CLD), a chlorinated polycyclic ketone pesticide, until 1993 in the French West Indies has resulted in long-term pollution of agricultural soils (10% of them exceed 1 mg kg(-1)). The aim of this study was to assess the impact of two tropical volcanic soils, an andosol and a nitisol, on CLD availability in piglets, using the relative bioavailability (RBA) approach. For both soils and relative to an oil matrix, RBA was close to 100%, indicating that CLD was not retained in the soil matrices during the piglet digestive process. Additionally, after a 14 day exposure period, liver and subcutaneous fat CLD concentrations exceeded the maximum residue limit (10 μg kg(-1) of fresh matter and 100 μg kg(-1) of fat for liver and subcutaneous fat, respectively) beyond a CLD ingestion of 2.1 and 6.8 μg CLD kg(-1) of body weight per day, respectively. Thus, rearing practices in CLD-contaminated areas should avoid involuntary soil ingestion by farm animals.