Bizeul Rémi, Lajoie Oriane, Cerdan Olivier, Pak Lai Ting, Foucher Anthony, Huon Sylvain, Grangeon Thomas, Evrard Olivier
Laboratoire des Sciences du Climat et de l'Environnement (LSCE-IPSL), Université Paris-Saclay, Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Orme des Merisiers, 91191 Gif-Sur-Yvette, France.
Laboratoire des Sciences du Climat et de l'Environnement (LSCE-IPSL), Université Paris-Saclay, Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Orme des Merisiers, 91191 Gif-Sur-Yvette, France.
Environ Pollut. 2025 Feb 1;366:125412. doi: 10.1016/j.envpol.2024.125412. Epub 2024 Dec 5.
The strong pest pressure on intensive banana cultivation in the French West Indies led to the intensive use of chlordecone (an organochlorine insecticide) between 1972 and 1993. Due to its high toxicity for the population and the environment, many studies were conducted on the transfer of chlordecone over the last 20 years. However, most studies focused on the dissolved fraction of chlordecone, while the particle-bound fraction was understudied. Therefore, this study reconstructs pluri-decadal erosion rates (i.e. 1980-2023) and associated chlordecone particle-bound transfers from soil and sediment cores sampled in a cultivated headwater catchment (Saint-Esprit, Martinique). Based on sediment accumulation analyses in an agricultural reservoir, high erosion rates (i.e. 10 t ha yr) were found in the investigated catchment during the study period, with values exceeding the estimated tolerable soil loss rate in tropical contexts (i.e. 2.2 t ha yr). Based on the analysis of soil cores sampled along a banana plantation hillslope, this study highlights the formation of colluvial deposits with high levels of chlordecone contamination. When these areas are affected by erosion processes, this leads to massive remobilization of particle-bound chlordecone to water bodies. Indeed, in sediment sampled in the downstream reservoir, we observed a drastic increase in these transfers since 2006, synchronous with changes in agricultural practices. This study therefore highlighted the occurrence of legacy contamination at toeslope positions, which was estimated to potentially persist for 4000 to 11,000 years. Such a residence time highlights the need to implement changes in land management to effectively reduce erosion of agricultural soils, particularly in areas identified as "temporary deposition zones" for chlordecone contamination, in order to protect downstream water bodies from chlordecone transfer. To achieve this, agricultural practices that may increase soil erosion, such as herbicide application or intensive ploughing, should be minimized. Overall, this study improved our understanding of erosion and associated chlordecone transfers in tropical environments.
在法属西印度群岛，集约化香蕉种植面临着严重的虫害压力，这导致在1972年至1993年间大量使用了十氯酮（一种有机氯杀虫剂）。由于其对人类和环境具有高毒性，在过去20年里开展了许多关于十氯酮迁移的研究。然而，大多数研究集中在十氯酮的溶解部分，而颗粒结合部分的研究较少。因此，本研究通过对在一个种植地上游集水区（马提尼克岛的圣埃斯普里）采集的土壤和沉积物岩芯进行分析，重建了数十年的侵蚀速率（即1980 - 2023年）以及相关的十氯酮颗粒结合迁移情况。基于对一个农业水库沉积物积累的分析，研究期间在所调查的集水区发现了高侵蚀速率（即10吨/公顷/年），其值超过了热带地区估计的可容忍土壤流失率（即2.2吨/公顷/年）。基于对沿香蕉种植山坡采集的土壤岩芯的分析，本研究突出了含有高浓度十氯酮污染的崩积物的形成。当这些区域受到侵蚀过程影响时，这会导致颗粒结合的十氯酮大量重新进入水体。事实上，在下游水库采集的沉积物中，我们观察到自2006年以来这些迁移量急剧增加，这与农业实践的变化同步。因此，本研究强调了在坡脚位置存在遗留污染，估计这种污染可能持续4000至11000年。如此长的停留时间凸显了实施土地管理变革的必要性，以有效减少农业土壤侵蚀，特别是在被确定为十氯酮污染“临时沉积区”的区域，从而保护下游水体免受十氯酮迁移的影响。为实现这一目标，应尽量减少可能增加土壤侵蚀的农业实践，如施用除草剂或深耕。总体而言，本研究增进了我们对热带环境中侵蚀及相关十氯酮迁移情况的理解。
