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National audience; L’exposition de l’Homme aux micro- et nanoplastiques concerne, en premier lieu, les barrières naturelles du corps ou barrières biologiques comme les barrières intestinale et pulmonaire. Les objectifs du projet TRANSPLAST sont de : 1. Caractériser les effets de particules de micro- et nanoplastiques sur les transporteurs membranaires humains de type ABC et SLC reconnus comme étant impactés par les contaminants chimiques ; 2. Préciser les conséquences en terme de fonctionnement des barrières hépatique et intestinale ; 3. Définir les interactions potentielles des transporteurs membranaires avec des polluants chimiques associés aux micro- et nanoplastiques (ex. bisphénol A, pesticides organochlorés, retardateurs de flamme)

International audience; Les contaminants chimiques, présents dans notre environnement, sont suspectés d’avoir des propriétés de type obésogène, diabétogène ou stéatogène c’est-à-dire de contribuer au développement de troubles métaboliques en perturbant la balance énergétique des organismes. Ceci concerne les plastifiants, des composés de la famille des organoétains ou encore certaines substances organochlorées, considérées comme des polluants organiques persistants. À ce jour, les mécanismes par lesquels ces contaminants contribuent au développement des stéatoses hépatiques non alcooliques (NAFLD ) restent méconnus.

In this study, liver samples of the European otter (Lutra lutra), great cormorant (Phalacrocorax carbo), and European catfish (Silurus glanis) from along the Loire River (France) were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), trace elements (lead, cadmium, copper, and mercury), Cs-134, and Cs-137. Organochlorine compounds were found in 100 % of the samples. Residue level of PCBs in these predators was the highest followed by DDTs and endosulfan, and maximal PCB values reached 1.61, 1.96, and 0.28 mg/kg wet weight for cormorants, otters, and catfish, respectively. DDTs, endosulfan, and lindane were the abundant pesticides in the livers of these predators. Concentrations of copper, lead, and cadmium in the livers of top predators were generally low; a potentially toxic level of lead was found in only one cormorant (34.9 mg/kg dry weight). Mean mercury concentrations in cormorant, otter, and catfish livers were 5.47, 4.68, and 2.71 mg/kg dry weight, respectively, and exceeded toxic thresholds for more than 40 % of the cormorants. Levels of organochlorine compounds and trace elements in these predators are generally below known toxic thresholds, but potential combined effects are not studied and warrant more investigations.

Les polluants organiques persistants se dégradent lentement dans l’environnement. Certains de ces polluants, ayant une activité hormono-mimétique, suscitent des inquiétudes liées notamment à la survenue et à la progression de cancers hormono-sensibles (ex. thyroïde, prostate, testicule, sein, ovaire). Mais leur dangerosité reste difficile à évaluer. L’objectif du projet IncuPE est de développer un outil d’analyse « haut débit » permettant d’évaluer les effets des polluants organiques persistants sur les capacités migratoires, invasives et prolifératives des cellules tumorales humaines hormono-sensibles.

Le principal objectif du projet de recherche METACHILD était de synthétiser les connaissances sur la relation entre l’exposition domestique aux pesticides et les cancers les plus fréquents de l’enfant (cancers du cerveau, leucémies) en réalisant des revues systématiques des études épidémiologiques disponibles complétées, si possible, par des méta-analyses qui combinent les données de l’ensemble des études sélectionnées et permettent une quantification du risque.

Le principal objectif du projet de recherche METACHILD était de synthétiser les connaissances sur la relation entre l’exposition domestique aux pesticides et les cancers les plus fréquents de l’enfant (cancers du cerveau, leucémies) en réalisant des revues systématiques des études épidémiologiques disponibles complétées, si possible, par des méta-analyses qui combinent les données de l’ensemble des études sélectionnées et permettent une quantification du risque.

Past applications of chlordecone, a persistent organochlorine pesticide, have resulted in diffuse pollution of agricultural soils, and these have become sources of contamination of cultivated crops as well as terrestrial and marine ecosystems. Chlordecone is a very stable and recalcitrant molecule, mainly present in the solid phase, and has a strong affinity for organic matter. To prevent consumer and ecosystem exposure, factors that influence chlordecone migration in the environment need to be evaluated. In this study, we measured the impact of incorporating compost on chlordecone sequestration in andosols as a possible way to reduce plant contamination. We first characterized the transfer of chlordecone from soil to plants (radish, cucumber, and lettuce). Two months after incorporation of the compost, soil-plant transfers were reduced by a factor of 1.9-15 depending on the crop. Our results showed that adding compost modified the fractal microstructure of allophane clays thus favoring chlordecone retention in andosols. The complex structure of allophane and the associated low accessibility are important characteristics governing the fate of chlordecone. These results support our proposal for an alternative strategy that is quite the opposite of total soil decontamination: chlordecone sequestration.

Plusieurs études se sont intéressées à l'effet possible des polychlorobiphényles (PCB) et des pesticides organochlorés. Une association entre exposition et survenue d’un cancer n’a pas été confirmée, mais le rôle des expositions survenant à certaines périodes clés de la vie et les interactions avec des facteurs de susceptibilité génétique restent très largement inexplorés. Le projet "CECILE-P/E " financé par le PNR EST en 2011 se focalise sur le rôle d'autres composés plus rarement étudiés incluant des dioxines et furanes, qui sont aussi des composés organochlorés persistants.

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 Kow 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.

International audience

The online version of this article (doi:10.1007/s11356-013-2095-x) contains supplementary material, which is available to authorized users.; International audience; When field pollution is heterogeneous due to localized pesticide application, as is the case of chlordecone (CLD), the mean level of pollution is difficult to assess. Our objective was to design a decision support tool to optimize soil sampling. We analyzed the CLD heterogeneity of soil content at 0-30- and 30-60-cm depth. This was done within and between nine plots (0.4 to 1.8 ha) on andosol and ferralsol. We determined that 20 pooled subsamples per plot were a satisfactory compromise with respect to both cost and accuracy. Globally, CLD content was greater for andosols and the upper soil horizon (0-30 cm). Soil organic carbon cannot account for CLD intra-field variability. Cropping systems and tillage practices influence the CLD content and distribution; that is CLD pollution was higher under intensive banana cropping systems and, while upper soil horizon was more polluted than the lower one with shallow tillage (< 40 cm), deeper tillage led to a homogenization and a dilution of the pollution in the soil profile. The decision tool we proposed compiles and organizes these results to better assess CLD soil pollution in terms of sampling depth, distance, and unit at field scale. It accounts for sampling objectives, farming practices (cropping system, tillage), type of soil, and topographical characteristics (slope) to design a relevant sampling plan. This decision support tool is also adaptable to other types of heterogeneous agricultural pollution at field level.

The Java Australia Dynamic Experiment high-resolution February–March 1992 conductivity-temperature-depth and chlorofluoromethane section obtained between Australia and Bali and on the sills between Flores, Sumba, Sawu, Roti, and the Australian continental shelf allows detailed examination of the water masses distribution and their inferred circulation. A sharp hydrological front between the Indonesian waters and the southern Indian Ocean waters is found between 13°S and 14°S in both seasons (February–March 1992 and August 1989). It separates the high-salinity surface waters to the south from the lower-salinity surface waters derived from the Indonesian Seas to the north. It reaches the surface in February 1992, whereas it was capped by a particularly low salinity surface layer in August 1989. Near Bali, the NW monsoon of February–March produces large intrusions of low-salinity water from the Java Sea, through Lombok Strait in the upper 100 m. At depth, the North Indian Intermediate Water, flowing along the Indonesian coast, brings salty, low-oxygen and low-chlorofluorocarbon water. It enters the Sawu Sea through Sumba Strait toward the east, while it undergoes strong mixing with the Indonesian Seas water. The primary pathway of the Indonesian waters is found north of the front and south of the North Indian Intermediate Water, between 13°S and 9°30′S, and the associated salinity minimum can be followed all across the Indian Ocean.

International audience; In the French West Indies, chlordecone (CLD), an organochlorine pesticide, which is highly persistent in the environment, was applied in banana plantations from 1972 to 1993 against the banana weevil Cosmopolites sordidus. Pollution surveys conducted in 2001 by the French Department of Health revealed the presence of chlordecone in soils, rivers, springs over large areas in Guadeloupe and Martinique islands. Contamination of drinking water, food crops, aquatic species by CLD has been observed as well as its presence in blood of men, pregnant women and newborns. There is therefore a large social concern about the extent and evolution of CLD pollution in the French West Indies and its impact on human health and ecosystems. From 2008 to 2012 a multidisciplinary project CHLORDEXCO took place to study the CLD fate in water, soils and the contamination characteristics of aquatic species and food crops. Here, we summarize results obtained on the processes controlling the spatial and temporal patterns of soil and water contamination at the scale of the banana cropping area in Guadeloupe and of the Perou catchment. The main soils in the contaminated areas are andosols and nitisols and formed from the weathering of volcanic ashes. They have a high organic carbon content and high content of secondary minerals, allophane for andosols and halloysite for nitisols. An analysis of the spatial distribution of CLD in soil over 1045 field plots showed that the soil type had a strong impact. Andosols, with a high sorption capacity (Koc 20 000 L/kg), had the highest CLD concentrations and stocks, unlike Nitisols, which had 10-fold lower sorption capacities. A significant « farm effect », due to between-farm variations of application times and amounts, was also noticed. The observed stocks of CLD clearly correspond to the accumulation in soil of successive treatments and thereby confirm the high persistence of CLD in soil also observed in incubation studies in soil microcosms. Soil column studies of the transport of aged CLD however showed that CLD concentration in percolation water varied little (5 to 10 μg/L) and were of same magnitude for both soils although their sorption properties and hydrodynamic behaviours differed with larger macropore flow in the andosols. At catchment scale, contamination of surface waters was permanent with CLD concentrations one order of magnitude less than in percolation water. Temporal variations of contamination were due to dilution effects caused by water from uncontaminated uphill areas. CLD concentrations were highest in base flow indicating that the main pathway of applied CLD to surface waters is by percolation and groundwater flow. In conclusion, contamination of soil and water in the banana cropped areas of the French West Indies is general and permanent. If no soil remediation strategies can be elaborated this severe environmental contamination will last over centuries as estimated by Cabidoche et al. (2009, Environ. Poll., 57, 1697-1705). Since CLD propagates mainly by subsurface flow, buffer strips, usually recommended in many regions to limit the pollution of water by pesticides, will not be useful.

International audience

The context of this study is the pollution of soils and water by a persistent organo-chlorinated insecticide, chlordecone, in a tropical environment. The application of chlordecone to control the banana black weevil has led to continuing diffuse pollution of soils, and to its being a source of contamination for cultivated plants, as well as for terrestrial and marine ecosystems. Chlordecone is toxic and stable and is considered to be a persistent organic pesticide. Consequently, the amounts of chlordecone that could migrate through the environment and contaminate agricultural products need to be controlled. We measured the impact of two composts (5% weight) on chlordecone sequestration in andosols. To this end, we first characterized the transfer of chlordecone from soil to water, and then its transfer from soil to plants. After 3 months of maturation, soil-water and soil-plant transfers were reduced by a factor of from 3 to 10. We also showed that adding compost to contaminated soils increases chlordecone sequestration because it leads to changes in soil microstructure in the form of pore collapse and closure of the fractal structure of the allophane content.

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; Chlordecone, one of the most persistent organochlorine pesticides, was applied between 1972 and 1993 in banana fields in the French West Indies, which results in long-term pollution of soils and contamination of waters, aquatic biota, and crops. As human exposure to chlordecone is mainly due to food contamination, early research was focused on chlordecone transfer to crops. Field trials were conducted to investigate chlordecone contamination of yam, sweet potato, turnip, and radish grown on a Ferralic Nitisol polluted by chlordecone. We also carried out trials on yam, courgette, and tomato under greenhouse conditions with homogenized Andosol and Nitisol, polluted by chlordecone to various extents. Our results indicated that i) all tubers were contaminated in accordance with the chlordecone content of the soils; ii) the plant contamination capacity of the Nitisol was greater than that of the Andosol; and iii) whatever the soil type, tuber contamination was related to the soil volumetric content of dissolved chlordecone. Nevertheless, no tubers showed sufficient chlordecone uptake for efficient soil decontamination by means of plant extraction. Soil contact accounted for most of the root crop contamination, which was inversely proportional to the tuber size. Internal transfer might also increase root crop contamination when the root central cylinder contained raw sap flow, as in the case of turnip or radish. Courgette fruits showed high contamination without soil contact. Thus, further research is needed to explore the pattern of both below- and aboveground plant chlordecone contamination and assess the hypothesis of its correlation with sap flow. Finally, we used our results to build a decision-making tool for farmers, relating soil pollution with the maximal contamination of the harvested organs to predict crop contamination and thus assisting farmers in making crop choices at planting in order to conform with the European Union's regulations.

Introduction : Eaux, végétaux et animaux sont contaminés par des polluants épandus dans l'environnement. Leurs degrés de contamination sont difficiles à déterminer car on ne peut tout analyser. De là, il est possible de considérer une approche globale et systémique de la contamination qui explicite les relations entre pollution des sols, des eaux et des organismes, éléments d'un même écosystème. Cette approche a été appliquée au cas de la Chlordécone (CLD). L'objectif a été ainsi de comprendre et caractériser les principaux mécanismes - physiques (transfert vers les rivières par ex.) et biologiques (capacité d'absorption par ex.) - régissant la dispersion de la molécule dans l'environnement jusqu'à son absorption par les plantes et animaux en vue d'expliquer leur niveau de contamination. Méthode : Différents dispositifs ont été mobilisés pour décrire le devenir de la CLD en partant de sa rétention dans le sol (instrumentation en colonne de sol), puis sa mobilisation et son transfert vers les nappes et les rivières (suivi hydrologique et de la qualité des masses d'eau sur un bassin versant guadeloupéen), jusqu'à son absorption par les végétaux (culture en milieu semi-contrôlé sur différents types de sol) et les animaux en rivière (impact chez le crustacé aquatique Macrobrachium faustinum). Résultats : Les résultats montrent que le principal réservoir de pollution est le sol. De 70 à 80% du stock de CLD du sol est potentiellement disponible à l'entraînement par lessivage, ce processus restant la voie majeure de décontamination des sols. De là, la rivière se contamine principalement du fait d'alimentations souterraines. Les concentrations moyennes dans les eaux restent faibles (moins de 1?g l-1) mais suffisantes pour observer une forte bioaccumulation de la CLD chez M. faustinum qui présente des anomalies de la croissance et de la physiologie. Chez les plantes, le degré de contamination des organes dépend de leur position dans le flux de sève brute qui transporte la CLD. A concentration en CLD équivalente, les nitisols apparaissent plus contaminants que les andosols. Conclusion et perspectives : Différents mécanismes à l'origine d'une contamination importante par la CLD des eaux, de certaines cultures ou animaux ont été identifiés. De plus, nos travaux ont permis de resituer la contamination dans le temps : le mode de dispersion de la CLD suggère une contamination quasi-permanente du milieu depuis les premiers épandages ; pour l'avenir, elle oblige à une surveillance des milieux à l'échelle du siècle ! Enfin, les résultats obtenus confirment l'intérêt de travailler à l'échelle englobante du bassin versant. Ils sont à l'origine d'un projet de mise en place de deux observatoires des pollutions agricoles, un en Martinique, l'autre en Guadeloupe, dédiés dans un premier temps à la CLD. Pour ces observatoires à vocation transdisciplinaire, le partenariat de recherche reste à construire. Ceci constitue un objectif majeur de la première année de projet.

National audience; Chlordecone is an organochlorine insecticide and it was used to fight against the banana black weevil (Cosmopolites sordidus) from 1971 to 1993 in the French West Indies. Chlordecone is not a mobile molecule and is very slowly or almost not degradable in aerobic soils. Its persistence is a long term one and technical remediation is not operational at this time, but soils stay fertile, even if they remain the main pollution source. Thus we have to face and manage this pollution. This leads to changes among agrosystems, whether on crop choice or on practices to reduce sanitary impact. Chlordecone crop uptake varies according to the type of plant and organ: roots and tubers are highly contaminated whether fruits (banana, pineapple, tomato, citrus, etc.) are chlordecone free. A management tool is now available for farmers to choose crops according to the field pollution level and to reduce the consumers’ exposure risk. Reciprocally, cropping systems have an influence on pollution dispersion at the field and watershed scales. Chlordecone pollutes water resources and aquatic organisms through leaching water from polluted fields. This article present the existing situation and sums up the knowledge available based on results from past and in progress projects on cropping systems management and transfer processes to the environment, as well as on their impacts on aquatic ecosystems.; La chlordécone, insecticide organochloré, était utilisée pour lutter contre le charançon du bananier (Cosmopolites sordidus) de 1971 à 1993. La chlordécone est peu mobile et se dégrade à une vitesse très lente, voire nulle dans les sols aérés. Sa persistance est donc longue, et la dépollution artificielle n'est pas opérationnelle actuellement. Cependant les sols restent fertiles même si ils constituent la principale réserve et source de pollution. Il faut donc gérer cette pollution. Cela implique des changements au sein des agrosystèmes, tant sur le choix des productions possibles que sur certaines pratiques agronomiques pour réduire les impacts sanitaires. Pour les espèces cultivées sur les parcelles polluées, certains organes sont très contaminés (tubercules), d'autres indemnes (fruits d'arbres, banane, ananas, tomate, etc.). Un outil de gestion est disponible pour les producteurs afin d'anticiper le choix des cultures et de réduire le risque d'exposition des consommateurs. Réciproquement, les systèmes de culture ont une incidence sur la dispersion de la molécule à l'échelle d'une parcelle et d'un bassin versant. La chlordécone contamine les ressources et les organismes aquatiques via les eaux de percolations issues des parcelles polluées. Cet article fait le point sur les principaux résultats disponibles et les projets en cours sur la gestion des agrosystèmes et les processus de transferts de la chlordécone vers l'environnement ainsi que leurs impacts sur les écosystèmes aquatiques.

Les PCB, les OCP et les PBDE ont été choisis comme molécules modèles pour suivre les mécanismes de bioaccumulation chez le rorqual commun (Balaenoptera physalus (Linnaeus)). Entre 2006 et 2009, 70 biopsies ont été collectées en mer Ligure, Méditerranée nord-occidentale. Parallèlement aux dosages chimiques, une caractérisation génétique du sexe des individus a également été réalisée. Les résultats obtenus mettent en évidence une contamination résiduelle des rorquals communs en PCB (1140 ± 856 g.ng-1 pf ; 4121 ± 3700 ng.g-1 pl), en OCP (1914 ± 1658 g.ng-1 pf ; 6643 ± 5959 ng.g-1 pl), ainsi qu'une faible contamination en PBDE (49 ± 47 ng.g-1 pf; 177 ± 208 ng.g-1 pl). Les teneurs en PCB et OCP sont cohérentes avec celles de la littérature, et semblent même dénoter d'une baisse de la contamination des rorquals communs sur ces 10 dernières années. Une influence du sexe sur les niveaux de contamination a clairement été mise en évidence; les femelles sont trois fois moins contaminées que les mãles. Cette différence s'explique par le fait que les femelles "dépurent" lors de la gestation et l'allaitement. Ces résultats ont permis de dresser un premier niveau de contamination des rorquals communs dans la mer Méditerranée témoignant de la contamination résiduelle en PCB et OCP, et d'une faible contamination en PBDE.

La chlordécone, insecticide organochloré de synthèse, était utilisée dans les bananeraies antillaises avant 1993. Pourtant, elle contamine encore les ressources en eau, certaines denrées, et des organismes aquatiques. Très tôt, la recherche agronomique s'est mobilisée pour répondre aux questions posées pour la gestion de cette crise : Où sont les sols pollués? Est-ce une pollution durable ? La molécule est peu mobile. Des cartes de risques, fondées sur leur occupation rétrospective en bananeraies, aboutissent à 1/5e de la SAU polluée en Guadeloupe, 2/5e en Martinique. Les sols riches en matière organique retiennent fortement la chlordécone. Elle ne se dégrade pas dans les sols aérés, seules les eaux de percolation peuvent la dissiper. Sa persistance est donc longue, d'un à quelques siècles selon les sols. La dépollution artificielle n'est pas actuellement opérationnelle. Il faut donc gérer cette pollution. Pour réduire l'exposition de la population et la contamination des denrées, les agriculteurs doivent disposer de systèmes de culture et d'élevage compatibles avec les niveaux de chlordécone des sols, restés fertiles. Un outil est disponible, il prend en compte le niveau de pollution de la parcelle et la contamination des cultures: certaines sont très contaminées (tubercules), d'autres indemnes (fruits d'arbres, banane, ananas, tomate,...).

BACKGROUND: The tobacco whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), has developed a high degree of resistance to several chemical classes of insecticides throughout the world. To evaluate the resistance status in West Africa, eight insecticides from different chemical families were tested using the leaf-dip method on four field populations collected from cotton in Benin, Togo and Burkina Faso. RESULTS: Some field populations showed a significant loss of susceptibility to pyrethroids such as deltamethrin [resistance ratio (RR) 3-5] and bifenthrin (RR 4-36), to organophosphates (OPs) such as dimethoate (RR 8-15) and chlorpyrifos (RR 5-7) and to neonicotinoids such as acetamiprid (RR 7-8) and thiamethoxam (RR 3-7). Bemisia tabaci was also resistant to pymetrozine (RR 3-18) and to endosulfan (RR 14-30). CONCLUSION: The resistance of B. tabaci to pyrethroids and OPs is certainly due to their systematic use in cotton treatments for more than 30 years. Acetamiprid has been recently introduced for the control ofwhiteflies.Unfortunately, B. tabaci populations from Burkina Faso seem to be already resistant. Because cross-resistance between these compounds has never been observed elsewhere, resistance to neonicotinoids could be due to the presence of an invasive B. tabaci biotype recently detected in the region. (Resume d'auteur)

International audience

International audience; Chlordecone is an organochlorine pesticide whose use is now forbidden but which persists in soils. It was used as an insecticide against the banana weevil from the 1970s to the early 1990s in the French West Indies. Late contamination of root vegetables (RVs) was revealed in 2002. In our work, we studied the mode of transfer of chlordecone from different types of tropical soil (Andosol, Ferralsol and Nitisol) to different RVs (dasheen, yam, sweet potato, turnip and radish) to explore plant sensitivity to contamination. We conducted complementary experiments: surveys, field trials, and mesocosm trials to link soil chlordecone content with plant chlordecone contamination. In all those experiments, RVs contamination was heterogeneous as soil pollution was heterogeneous, but dispersion of the chlordecone molecule was the same for each crop. Due to this dispersion, the soil type did not significantly affect contamination. Average contamination values measured in harvested organs were positively correlated to chlordecone soil content. Belowground organs themselves were contaminated heterogeneously depending on where there was direct contact between the organ and contaminated soil. The cortex was more highly contaminated than the pulp (up to ten times more). These two results thus support the hypothesis that contamination by direct contact between the chlordecone molecule and the plant organ is the most important mode of transfer in RVs. This has already been demonstrated in the yam Discorea cayenensis, whose tubers were chlordecone free even when the root system explored contaminated soil. Chlordecone diffusion into the plant was very weak suggesting that it is a passive process in RVs. A common model, based on morphology and duration of the soil/organ contact, accounted for the RVs contamination. We calculated an envelope curve of the relationship between soil chlordecone content and RVs contamination and the maximum transfer ratio observed was 1/5. This envelope curve which represents zero risk of contamination was calculated for crops on both Andosol and Ferralsol. This relationship is thus a decision tool to determine whether or not there is a risk involved in cultivating roots and tubers based on the result of soil analysis. With this tool, the risk of contamination can be foreseen at planting which is preferable to analyzing the product at the harvest stage. Further studies are in progress to determine the sensitivity of other mainly horticultural crops and fruits, and to analyze the contamination of aboveground organs. Factors that govern the bioavailability of the chlordecone molecule in the soil for the plants, like water, organic matter content, type of clay, need to be analyzed in more detail to better understand chlordecone transfer to plants and thus improve pollution management

Une synthèse des connaissances sur la pollution par les organochlorés aux Antilles a été réalisée dans le cadre du Groupe d'étude et de prospective de juin 2005 à mars 2006. La connaissance acquise à ce jour sur le vo-let agronomique et sur la contamination des sols et des cultures est intégrée. Les contaminations par la dieldrine et le BHCH étant sporadiques et peu durables, cet article est focalisé sur la chlordécone utilisée contre le charançon (Cosmopolites sordidus) en bananeraies de 1971 à 1993. Cette molécule est très stable, la pollution des sols est durable et hétérogène dans les parcelles. Le transfert vers les plantes est lié à la teneur dans le sol, au type de sol et au type de culture. La voie de contact est la voie privilégiée de contamination des organes souterrains (racine, tubercule). Un transfert par diffusion vers les organes aériens (tige, feuille, fruit) existe, mais ces derniers sont bien plus faiblement contaminés. Peu de données sont disponibles pour les productions animales. On doit porter une attention particulière aux productions informelles. À partir de limites maximales dans les denrées, un outil de gestion du risque est proposé. Des référentiels de contamination utilisant les relations existant entre teneur du sol et teneur de la plante permettent d'anticiper le risque à partir de l'analyse de sol. Cet outil implique un dispositif analytique local et des connaissances sur la sensibilité des cultures à la contamination. Les traitements physiques, la phyto-extraction et la dégradation biologique ne sont pas envisageables à court terme. Les filières de reconversion possibles (productions non alimentaires) ne seront valides qu'après évaluation technico-économique.

Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analysed in the muscle of various edible marine crustaceans (spider crab, edible crab, velvet swimming crab and Norway lobster) from the Brittany and Normandy coasts (France). The highest concentrations were measured in species collected from Antifer (Seine Bay). PCB and PBDE patterns in crustacean muscles were similar and independent of the geographical area with the predominance of the high chlorinated PCBs (CB 15 3, 138, 118 and 180), and of a few PBDE congeners (BDE47, BDE99, WE 100 and BDE28). Oppositely, dioxin contamination differed with site. The major component in crustaceans from the Seine Bay was 2378-TCDF, whereas specimens from cleaner areas had higher relative concentrations of OCDD. Finally, the comparison of the spider crab contaminant profiles to those measured in mussel and sea bass highlighted two different trends: decapod crustaceans possess relatively strong capacity to metabolise PCBs and PBDEs; however these species might be used as bioindicators for dioxin pollution monitoring in the marine coastal environment. (C) 2007 Elsevier Ltd. All rights reserved.

National audience

Le chlordécone, insecticide organochloré, a été utilisé de 1981 à 1993 aux Antilles françaises en bananeraies contre le charançon Cosmopolites sordidus. Très persistant, l'insecticide se retrouve à ce jour dans l'environnement. En Martinique, des mesures effectuées à partir de 1999 ont montré la présence de chlordécone dans certaines eaux de captage d'eau potable. Des analyses effectuées de mai 2003 à mai 2004 montrent une contamination de certains sols ; des analyses de denrées végétales et animales révèlent la présence de résidus dans certains légumes racine (mais ni fruit ni légume aériens) et produits animaux. Aussi des mesures ont déjà été prises pour les eaux de captage (fermeture d'un forage et purification de l'eau captée dans une rivière), les légumes racines (surveillance des légumes issus de parcelles aux sols contaminés avec mise hors circuit de commercialisation s'ils sont contaminés), les produits non utilisés (collecte de PPNU), les poissons (interdiction de pêche à pied dans certains secteurs, fermeture d'une unité piscicole) et l'information du public. Par ailleurs des travaux sont en cours pour préciser l'évaluation de la contamination des sols (cartographie) et celle des transferts des sols vers les plantes, et évaluer les expositions des consommateurs dans le but d'établir des LMR. Les résultats permettront d'adapter et améliorer le plan d'action basé pour l'instant sur les connaissances actuelles et le principe de précaution.

The ventilation of the main thermocline associated with the formation of Subtropical Mode Water (STMW) and Subantarctic Mode Water (SAMW) within the Brazil/Malvinas Confluence region is investigated using satellite data, hydrographic data, and dissolved CFCs as transient tracers. During the winter of 1994, two types of STMW were observed. Both types, 26.24 sigma theta and 26.46 sigma theta were formed within the warm pool of the South Atlantic Central Water (SACW). The SAMW is found on the 27.10 sigma theta density surface. This surface lies in the minimum salinity layer of the Antarctic Intermediate Water (AAIW). The mode waters are dated using CFC ratios. To our knowledge, this is the first estimate of the age of the mode waters in the region using the CFC-113:CFC-11 ratio method. The lighter STMW was being formed during the cruise. The heavier STMW was found to be 6 plus or minus 3 years old and is thought to have circulated in the subtropical gyre without losing its primary properties. The SAMW, or the lightest AAIW has an age of 3 plus or minus 2 years. This water is very young compared with the oldest (10 plus or minus 5 years) and heaviest component of the AAIW; which circulates within the subropical gyre. The formation of the STMW in the confluence region is dependent on the southward extension of the Brazil Current. (Résumé d'auteur)

This paper presents CFC and nontransient tracer observations in the western equatorial Atlantic Ocean on repeated sections along 7°30′N, the 35°W meridian, and a transect crossing the Ceara Rise. Three World Ocean Circulation Experiment cruises have been carried out in this area, in February-March 1993 (CITHER 1) and September-October 1995 and April-May 1996 (ETAMBOT 1 and 2). Together with the tracer data, the direct current measurements are used to deduce the circulation pathways. The data confirm the principal circulation features of the Upper North Atlantic Deep Water within the area. The Deep Western Boundary Current flows southward along the continental slope, while, adjacent to the DWBC, there is a northward flow corresponding to the DWBC recirculation whose origin appears variable. The largest variability is observed along the 35°W meridional section, where the DWBC bifurcates eastward north of 3°S but the eastward equatorial flow does not appear to be permanent. At the Middle North Atlantic Deep Water level, CFC distributions exhibit the most important contrast between waters of northern and southern origin. The circulation at the Lower North Atlantic Deep Water level, mainly controlled by the topography, looks more permanent because the DWBC is regularly observed during the three cruises, and there is no evidence for a northwestward recirculation along the Mid-Atlantic Ridge. The transient behavior of CFC distributions, which is superimposed on local circulation effects, can be seen clearly through their temporal evolution within the DWBC. The variability of the deep circulation observed during the 1993–1996 interval rules out a dominant variability in response to semi annual forcing.

International audience; Chlorofluoromethanes (CFMs) F-11 and F-12 were measured during August 1991 and November 1992 in the Romanche and Chain Fracture Zones in the equatorial Atlantic. The CFM distributions showed the two familiar signatures of the more recently ventilated North Atlantic Deep Water (NADW) seen in the Deep Western Boundary Current (DWBC). The upper maximum is centered around 1600 m at the level of the Upper North Atlantic Deep water (UNADW) and the deeper maximum around 3800 m at level of the Lower North Atlantic Deep Water (LNADW). These observations suggest a bifurcation at the western boundary, some of the NADW spreading eastward with the LNADW entering the Romanche and the Chain Fracture Zones. The upper core (σ1.5=34.70 kg m-3) was observed eastward as far as 5°W. The deep CFM maximum (σ4=45.87 kg m-3), associated with an oxygen maximum, decreased dramatically at the sills of the Romanche Fracture Zone: east of the sills, the shape of the CFM profiles reflects mixing and deepening of isopycnals. Mean apparent water "ages" computed from the F-11/F-12 ratio are estimated. Near the bottom, no enrichment in CFMs is detected at the entrance of the fracture zones in the cold water mass originating from the Antarctic Bottom Water flow.

CFM (CCl3F or freon F-11 and CCl2F2 or freon F-12) measurements were made on board the R.V. Atalante as part of a quasi-synoptic survey of the tropical Atlantic Ocean. The work was carried out during the CITHER 1 cruise, part of the French CITHER program (Circulation THERmohaline) between January and March 1993. Two zonal sections at 4°30 S and 7°30N (the A7 and A6 WOCE sections) and two meridional sections at 35°W and 3°50 W were sampled for CFMs between the African and South American continents. The results reported here deal primarily with the North Atlantic Deep Water. The CITHER 1 sections were made just 10 years after the first CFMs snapshot of the tropical Atlantic ocean obtained during the Transient Tracers in the Ocean Program.

La lutte contre les tsé-tsé vise à éliminer surtout les glossines d'intérêt vétérinaire afin d'ouvrir au bétail de nouvelles surfaces pâturables, principalement en zones subhumide ou humide. Elle a reposé longtemps sur l'utilisation massive des insecticides rémanents par application terrestre (D. D.T., dieldrine, endosulfan) , ce qui représentait des contraintes importantes : nécessité de stratégies élaborées mobilisatrices de moyens humains et matériels importants, dépôts d'insecticides certes sélectifs mais élevés, progressions lentes sur le terrain limitant les surfaces libérées au cours d'une saison sèche.

Examen de 15 matières actives appartenant aux 4 familles d'insecticides actuellement utilisés au Tchad en culture cotonnière (organo-chlorés, organo-phosphorés, carbamates et pyréthrinoïdes) en application topique sur la chenille enrouleuse de feuilles Syllepte derogata (F.). Les résultats obtenus au champ et au laboratoire ont permis de classer ces matières actives par ordre d'efficacité croissante vis-à-vis de ce ravageur. Ils permettent d'émettre une hypothèse sur l'expansion de ce ravageur phyllophage en culture cotonnière