Pascal-Lorber Sophie, Létondor Clarisse, Liber Yohan, Jamin Emilien L, Laurent François
ECOLAB, Université de Toulouse, CNRS, INPT, UPS , Toulouse, France.
ADEME , F-49000 Angers, France.
J Agric Food Chem. 2016 Jan 20;64(2):409-15. doi: 10.1021/acs.jafc.5b05115. Epub 2016 Jan 7.
Chlordecone (CLD) is a persistent organic pollutant (POP) that was mainly used as an insecticide against banana weevils in the French West Indies (1972-1993). Transfer of CLD via the food chain is now the major mechanism for exposure of the population to CLD. The uptake and the transfer of CLD were investigated in shoots of maize, a C4 model plant growing under tropical climates, to estimate the exposure of livestock via feed. Maize plants were grown on soils contaminated with [(14)C]CLD under controlled conditions. The greatest part of the radioactivity was associated with roots, nearly 95%, but CLD was detected in whole shoots, concentrations in old leaves being higher than those in young ones. CLD was thus transferred from the base toward the plant top, forming an acropetal gradient of contaminant. In contrast, results evidenced the existence of a basipetal gradient of CLD concentration within leaves whose extremities accumulated larger amounts of CLD because of evapotranspiration localization. Extractable residues accounted for two-thirds of total residues both in roots and in shoots. This study highlighted the fact that the distribution of CLD contamination within grasses resulted from a conjunction between the age and evapotranspiration rate of tissues. CLD accumulation in fodder may be the main route of exposure for livestock.
十氯酮（CLD）是一种持久性有机污染物（POP），曾主要用作杀虫剂，用于防治法属西印度群岛的香蕉象鼻虫（1972年至1993年）。如今，CLD通过食物链的转移是人群接触CLD的主要途径。本研究对热带气候下生长的C4模式植物玉米的茎进行了CLD吸收和转移的研究，以评估牲畜通过饲料接触CLD的情况。在可控条件下，将玉米植株种植在被[¹⁴C]CLD污染的土壤中。放射性的最大部分与根部相关，接近95%，但在整个茎中都检测到了CLD，老叶中的浓度高于幼叶。因此，CLD从基部向植株顶部转移，形成了污染物的向顶梯度。相反，结果表明叶片内存在CLD浓度的向基梯度，由于蒸散作用的局部化，叶片两端积累了较多的CLD。可提取残留物在根部和茎部均占总残留物的三分之二。本研究强调了这样一个事实，即禾本科植物中CLD污染的分布是由组织的年龄和蒸散速率共同作用导致的。饲料中CLD的积累可能是牲畜接触CLD的主要途径。
