Magalie Lesueur-Jannoyer

Determination of soil content in chlordecone (organochlorine pesticide) using near infrared reflectance spectroscopy (NIRS).

Chlordecone is a toxic organochlorine insecticide that was used in banana plantations until 1993 in the French West Indies. This study aimed at assessing the potential of near infrared reflectance spectroscopy (NIRS) for determining chlordecone content in Andosols, Nitisols and Ferralsols from Martinique. Using partial least square regression, chlordecone content conventionally determined through gas chromatography-mass spectrometry could be correctly predicted by NIRS (Q(2) = 0.75, R(2) = 0.82 for the total set), especially for samples with chlordecone content <12 mg kg(-1) or when the sample set was rather homogeneous (Q(2) = 0.91, R(2) = 0.82 for the Andosols). Conventional measures and NIRS predictions were poorly correlated for chlordecone content >12 mg kg(-1), nevertheless ca. 80% samples were correctly predicted when the set was divided into three or four classes of chlordecone content. Thus NIRS could be considered a time- and cost-effective method for characterising soil contamination by chlordecone.

Contamination of free-range ducks by chlordecone in Martinique (French West Indies): A field study

The former use of chlordecone (CLD) in the French West Indies has resulted in long-term pollution of soils and subsequently of food chains. In contaminated areas, free-range ducks used to control weeds in orchards may be exposed to CLD through polluted soil ingestion. The question arises whether they may be consumed. Muscovy ducks were raised on a guava orchard planted on a soil moderately contaminated (410 μg CLD/kg dry matter). Ducks were raised indoor up to 6 weeks of age and allowed to range freely outdoors thereafter. Twenty-nine females were sequentially slaughtered by groups of 2 to 5 ducks, after 4, 16, 19, 22 or 26 weeks spent in the orchard or after 16-17 weeks in the orchard followed by 3, 6 or 9 weeks in a closed shelter for depuration. CLD concentration increased from 258 to 1051, 96 to 278, 60 to 169 and 48 to 145 μg/kg fresh matter (FM) as the exposure through grazing increased from 4 to 22 weeks, in liver, abdominal fat and leg with and without skin, respectively. Eggs collected in the orchard contained up to 1001 μg CLD/kg FM. All these values exceeded the Maximum Residue Limit (MRL) of 20 μg/kg FM. CLD concentration in all tissues was divided by around 10 within the 9-week confinement period. Despite this quite rapid decontamination, it is estimated that 12-13 weeks would be required to achieve the MRL in liver and in eggs, and 5-6 weeks in leg muscle. Such durations would be too long in practice. Thus, the consumption of products from free-range ducks should be avoided, even in areas mildly contaminated with CLD.

Field validation of chlordecone soil sequestration by organic matter addition

PurposeThe use of chlordecone (CLD) has caused pollution of soils, which are now a source of contamination for crops and ecosystems. Because of its long-term impacts on human health, exposure to CLD is a public health concern and contamination of crops by CLD must be limited. To this end, we conducted field trials on chlordecone sequestration in soil with added compost.Materials and methodsThe impact of added compost on chlordecone sequestration was measured in nitisols. After characterization of the soil, the transfer of chlordecone from soil to water was assessed in a leaching experiment and from soil to two crop plants in a nitisol plot. Finally, to understand the underlying processes, changes in CLD content were measured in soil fractions and soil porous properties were assessed after the addition of compost.Results and discussionA rapid seven-fold decrease in water extractable CLD was observed in amended soils. Five percent amendment led to a significant reduction in the contamination of crops by CLD; edible radish tubers were 50% more contaminated without added compost and cucumber fruits were 60% more contaminated. After the addition of compost, CLD content increased in the fraction of pre-humified or partially mineralized organic debris. Finally, in contrast to andosols, adding compost to nitisols did not affect the soil microstructure.ConclusionsIncreasing chlordecone sequestration by adding compost could be an alternative solution until soil decontamination techniques become available. This could be a provisional way to control further release of CLD from contaminated soils towards other environmental compartments.

Soil Type and Growing Conditions Influence Uptake and Translocation of Organochlorine (Chlordecone) by Cucurbitaceae Species

Chlordecone (CLD), an organochlorine insecticide, and other persistent organic pollutants continue to contaminate the environment worldwide and have adverse effects on human health through food exposure. Cucurbitaceae take up weathered hydrophobic pollutants from the soil and translocate them to their shoots. As Cucurbitaceae are an important part of the diet in the French West Indies, they are among the main contributors to total dietary intake of CLD. We analyzed the contamination by CLDs (CLD and 5b-hydroCLD) of four cucurbits grown in the field and/or in the greenhouse. Different physiological (crop species) and environmental (soil type, growth conditions) variables were shown to influence uptake of the pollutant from the soil by the crop. Cucurbita species (zucchini and pumpkin) were more contaminated than Cucumis sativus (cucumber), and Sechium edule (christophine or chayote) translocated CLDs to fruits very poorly compared with cucumber and pumpkin. Greenhouse conditions and non-allophanic (nitisols and ferralsols) soils favored plant contamination more than field conditions and allophanic soils (andosols).

Effect of home food processing on chlordecone (organochlorine) content in vegetables

Decades after their use and their ban, organochlorine pesticides still pollute soil, water and food and lead to human and ecosystem exposure. In the case of chlordecone, human exposure is mainly due to the consumption of polluted food. We studied the effect of preparation and cooking in five vegetable products, three root vegetables (yam, dasheen and sweet potato) and two cucurbits (cucumber and pumpkin), among the main contributors to exposure to chlordecone in food in the French West Indies. Boiling the vegetables in water had no effect on chlordecone content of the vegetables and consequently on consumer exposure. The peel was three to 40-fold more contaminated than the pulp except cucumber, where the difference was less contrasted. The edible part is thus significantly less contaminated and peeling is recommended after rinsing to reduce consumer exposure, particularly for food grown in home gardens with contaminated soils. The type of soil had no consistent effect on CLD distribution but plot did. Peel and pulp composition (lipids and fibers) appear to partially account for CLD distribution in the product.

Comparative fate of an organochlorine, chlordecone, and a related compound, chlordecone-5b-hydro, in soils and plants

We address the problem of the comparative environmental fate of a pesticide, chlordecone (CLD), and a related compound, chlordecone-5b-hydro (CLD-5b-hydro). We used a large database including data from two types of contaminated volcanic soils, andosol and nitisol, and thirteen crops grown in the French West Indies in historically polluted soils. We performed in-depth statistical analysis of the effect of different parameters (soil type, crop, organ, etc.) on the ratio of CLD-5b-hydro to CLD in both soils and plants. The environmental fate of the two compounds differed depending on the type of soil. Proportionally, more CLD-5b-hydro than CLD was measured in nitisols than in andosols. Compared to CLD, we also found a preferential transfer of CLD-5b-hydro from the soil to the plant. Finally, mobilization of the two compounds differed according to the species of crop but also within the plant, with increasing ratios from the roots to the top of the plant. The properties of the compound played a key role in the underlying processes. Because CLD-5b-hydro is more soluble in water and has a lower K(ow) than CLD, CLD-5b-hydro (1) was more easily absorbed from soils by plants, (2) was less adsorbed onto plant tissues and (3) was transported in greater quantities through the transpiration stream. Due to the amounts of CLD-5b-hydro we measured in some plant parts such as cucurbit fruits, an assessment of the toxicity of this CLD monodechlorinated product is recommended.