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International audience; The widespread use of pesticides in agriculture during the last several decades has contaminated soils and different Critical Zone (CZ) compartments, defined as the area extended from the top of the vegetation canopy to the groundwater table, and it integrates interactions of the atmosphere, lithosphere, biosphere, and hydrosphere. However, the long-term fate, storage, and transfer dynamics of persistent pesticides in CZ in a changing world remain poorly understood. In the French West Indies, chlordecone (CLD), a toxic organochlorine insecticide, was extensively applied to banana fields to control banana weevil from 1972 to 1993 after which it was banned. Here, to understand CZ trajectories we apply a retrospective observation based on marine sediment core analyses to monitor long-term CLD transfer, fate, and consequences in Guadeloupe and Martinique islands. Both CLD profiles show synchronous chronologies. We hypothesized that the use of glyphosate, a postemergence herbicide, from the late 1990s onward induced CZ modification with an increase in soil erosion and led to the release of the stable CLD stored in the soils of polluted fields. CLD fluxes drastically increased when glyphosate use began, leading to widespread ecosystem contamination. As glyphosate is used globally, ecotoxicological risk management strategies should consider how its application affects persistent pesticide storage in soils, transfer dynamics, and widespread contamination.

International audience; In Guadeloupe, the use between 1972 and 1993 of chlordecone, an organochlorine insecticide, has permanently contaminated the island’s soil, thus contaminating the food chain at its very beginning. There is today a strong societal requirement for an improved mapping of the contaminated zones. Given the extent of the areas to be covered, carrying out soil tests on each plot of the territory would be a long and expensive process. In this article, we explore a method of demarcating polluted areas. The approach adopted consists in carrying out, using surface water analyses, a hydrological delimitation that makes it possible to distinguish contaminated watersheds from uncontaminated ones. The selection of sampling points was based on the spatial analysis of the actual and potential contamination data existing at the beginning of the study. The approach was validated by soil analyses, after having compared the contamination data of the watersheds with the soil contamination data of the plots within them. The study thus made it possible to highlight new contaminated areas and also those at risk of contamination and to identify the plots to be targeted as a priority during future analysis campaigns by State services.

International audience; The actual health risk and associated diseases induced by the presence of pesticides and other organic pollutants in most environmental media worldwide are largely underestimatedbecause current analytical methods measure only the extractable fraction of the pollutant, whereas there is now ample evidence that a large part of pollutants are trapped as bound residues in complex organo-mineral matrixes, and are thus unanalyzable by current tools. Once trapped, pollutants can be stored for long periods, then released in the biosphere upon suitable conditions such as soil erosion and climate change. This ‘resurrection’ and underlying mechanisms of trapping, storage and release are poorly known. Here we discuss the limit of knowledge on bound pollutants and their later release, with examples of organochlorines in glaciers, vineyards and banana plantations. Unexpectedly, soil application of a modern pesticide such as glyphosate, can lead to the resurrection of ancient, actually banned pesticides such as chlordecone and dichlorodiphenyltrichloroethane (DDT) (Fig. 1).

International audience; Groundwater resources are essential for the supply of drinking water in the European Union but significant uncertainties surround their quality. In this context, our article analyzes the factors that influence the cooperation of key stakeholders to prevent the risk of diffuse pollution from agriculture. We built on the institutional rational choice approach and the social-ecological system framework to design our analytical framework and hypotheses. We applied this analytical framework to two cases of cooperation involving drinking water suppliers and farmers in the management of the risk of non-point source pollution from agriculture in France. Our results show that cooperation emerges when the water resource is important for water suppliers to take on the leadership. Our results also characterize the role played by uncertainties and risk in getting stakeholders involved, and finally, suggest that cooperation depends on the size and predictability of the resource system.

International audience; Chlordecone (CLD), used to control the Cosmopolites sordidus banana weevil and released from polluted banana plantations, continues to contaminate ecosystems in the French Caribbean. Edible plants have been actively studied for risk prevention, but trees have not, even though they could play a significant role in future remediation strategies. CLD contents were analysed in 24 pioneer trees belonging to 13 species found in abandoned banana plantations inGuadeloupe, at three contaminated sites on Nitisols (Site 1) and Andosols (Sites 2 and 3). Samples were taken from each tree: wood in the basal part of the trunk and soil at its foot and their CLD content was measured by the analytical laboratory for the Drôme département (26) in Valence, France. Mean CLD contents in the top 30-centimetre soil layer from sites 1, 2 and 3 were 2,543 ± 702, 5,251 ± 1,102 and 875 ± 865 μg/kg dry soil respectively. Of the trees, 96% werecontaminated. The CLD content in trees growing on Nitisols (3,406 ± 1,658 μg/kg dry wood) was at least 5 times higher than in trees growing on Andosols (299 ± 314 and 226 ± 378 μg/kg), but no clear relationships were found with soil CLD contents. Calculations of available CLD dissolved in the soil liquid phase using equations and soil datasets in the literature showed higher available CLD contents in Nitisols than in Andosols and a linear relationship between CLD available in soil and concentrations of CLD in wood, regardless of the type of soil. Trees growing on Nitisols are the plants most highly contaminated by CLD of all the plants in which this compound has been studied so far. With a plant-to-soil bioconcentration ratio around 150 l/kg, the consistent CLD uptake efficiency of the trees needs to be taken into account in further research for CLD remediation.; Le chlordécone (CLD), utilisé pour lutter contre le charançon du bananier Cosmopolites sordidus et libéré par des bananeraies polluées, continue de contaminer les écosystèmes des Antilles françaises. Les plantes comestibles ont été activement étudiées pour la prévention des risques, mais pas les arbres, alors même qu'ils pourraient jouer un rôle important dans les stratégies de dépollution. Les teneurs en CLD ont été analysées sur 24 arbres pionniers appartenant à 13 essences présentes dans des bananeraies abandonnées en Guadeloupe, sur trois sites contaminés sur nitisols (site 1) et andosols (sites 2 et 3). Des échantillons de bois ont été prélevés sur chaque arbre dans la partie basale du tronc et dans le sol à son pied. Leur teneur en CLD a été mesurée par le laboratoire d'analyses départemental de la Drôme (26) à Valence, France. Les teneurs moyennes en CLD dans la couche supérieure de 30 centimètres du sol des sites 1, 2 et 3 étaient respectivement de 2 543 ± 702, 5 251 ± 1 102 et 875 ± 865 µg/kg de sol sec. Parmi les arbres, 96 % étaient contaminés. La teneur en CLD des arbres poussant sur nitisols (3 406 ± 1 658 µg/kg de bois sec) était au moins cinq fois plus élevée que celle des arbres sur andosols (299 ± 314 et 226 ± 378 µg/kg), mais aucune relation nette n'a été établie avec la teneur en CLD du sol. Le calcul du CLD disponible dissous en phase liquide dans le sol, à l'aide d'équations et de séries de données pédologiques de la littérature, a montré des teneurs en CLD disponible plus élevées dans les nitisols que dans les andosols et une relation linéaire entre le CLD disponible dans le sol et les concentrations de CLD dans le bois, quel que soit le type de sol. Les arbres poussant sur nitisols sont les espèces végétales les plus fortement contaminées par le CLD parmi toutes celles dans lesquelles ce composé a été étudié jusqu'à présent. Avec un rapport de bioconcentration plante-sol d'environ 150 l/kg, l'efficacité soutenue d'absorption de CLD par les arbres doit être prise en compte dans les recherches futures sur la dépollution des milieux contaminés par le chlordécone.

CONTEXT Chronic environmental pollutions are one of the most striking examples of negative externalities of intensive agriculture. To address this issue, an agroecological transition is necessary, requiring new design methods: While most design methods are suited to the field or farm scale, some innovations require an approach at the scale of the territory. OBJECTIVE In this article, we propose a new method to design an agricultural territory aiming to overcome an environmental pollution issue, i.e. to identify one or more combinations of agricultural practices, implemented by the farmers of the territory that reduce water pollution. METHODS We implemented the new method following three steps: first, we used a sociotechnical diagnosis to identify cognitive biases that prevent the actors from innovating in a disruptive way. Second, we used the K C method (based on C K theory) to allow actors to innovate in a disruptive way. Third, we used a serious game to continue the design of the innovations and to test and assess them in a safe place. We implemented this new method in the Galion River watershed in Martinique (French West Indies) whose river is polluted by herbicides. RESULTS AND CONCLUSION Using the method, actors have overcome existing path dependencies. Based on this, the method made it possible to design different innovations across scales in a participative way and with a systemic territorial point of view. Here, actors designed 15 innovations that enhance either the territory or the pooling of its resources. Among these, there was the sharing of the service of an itinerant breeder or the implementation of an ecotouristic circuit. Actors combined innovations across scales into three scenarios that created a new agricultural territory with fewer agricultural herbicides in the river. SIGNIFICANCE We suggest adding two participatory steps to improve the level of genericity of the method: a first step to discuss the initial question and the general organisation of the participatory process, followed by a second step dealing with how to insert the designed innovations in the serious game. Finally, we recommend this method in other territories requiring collective practice changes.

L'ensemble des activités en lien avec l'eau du lac de Guiers au Sénégal a potentiellement des conséquences importantes sur son état écologique. Cet article part du constat que la pollution par les pesticides concentre l'essentiel des débats et des actions entreprises tandis que l'enrichissement en nutriments des eaux du lac (représentant un risque d'eutrophisation) n'est un problème que rarement évoqué. Ce constat conduit les auteurs à s'interroger sur les facteurs sociopolitiques qui conduisent à " l'invisibilisation " de certaines causes de dégradation des milieux aquatiques. En nous appuyant sur une enquête de terrain auprès des gestionnaires et usagers du lac, nous montrons les concurrences entre les différents services administratifs qui conduisent à diverses formes de segmentation des causes de dégradation et à la sélection de l'une d'entre elles. Nous montrons ensuite comment cette formalisation du problème est diffusée et renforcée par la mise en oeuvre de bonnes pratiques agricoles, essentiellement centrées sur la question des produits phytosanitaires et relayées par des acteurs territoriaux. Cette analyse de la construction institutionnelle de l'ignorance est enfin complétée par une étude des représentations que les usagers se font de la dégradation de leur lac, permettant d'identifier les dynamiques sociales, les conflits et les jeux de pouvoir autour de l'appropriation de l'espace et de l'accès à l'eau, qui conduisent à l'invisibilisation du problème de l'eutrophisation.

PurposeIn tropical cropping systems, pesticides are extensively used to fight pests and ensure high crop yields. However, pesticide use also leads to environmental and health impacts. While pesticide emissions and impacts are influenced by farm management practices and environmental conditions, available Life Cycle Inventory (LCI) emission models and Life Cycle Impact Assessment (LCIA) toxicity characterization models are generally designed based on temperate conditions. There is, hence, a need for adapting LCI and LCIA models for evaluating pesticides under tropical conditions. To address this need, we aim to identify the characteristics that determine pesticide emissions and related impacts under tropical conditions, and to assess to what extent LCI and LCIA models need to be adapted to better account for these conditions.MethodsWe investigated the state-of-knowledge with respect to characteristics that drive pesticide emission patterns, environmental fate, human and ecological exposures, and toxicological effects under tropical conditions. We then discuss the applicability of existing LCI and LCIA models to tropical regions as input for deriving specific recommendations for future modeling refinements.Results and discussionOur results indicate that many pesticide-related environmental processes, such as degradation and volatilization, show higher kinetic rates under tropical conditions mainly due to higher temperatures, sunlight radiation, and microbial activity. Heavy and frequent rainfalls enhance leaching and runoff. Specific soil characteristics (e.g., low pH), crops, and cropping systems (e.g., mulching) are important drivers of distinct pesticide emission patterns under tropical conditions. Adapting LCI models to tropical conditions implies incorporating specific features of tropical cropping systems (e.g., intercropping, ground cover management), specific drift curves for tropical pesticide application techniques, and better addressing leaching processes. The validity domain of the discussed LCI and LCIA models could be systematically extended to tropical regions by considering tropical soil types, climate conditions, and crops, and adding active substances applied specifically under tropical conditions, including the consideration of late applications of pesticides before harvest and their effect on crop residues and subsequent human intake.ConclusionsCurrent LCI and LCIA models are not fully suitable for evaluating pesticide emissions and impacts for crops cultivated in tropical regions. Models should be adapted and parameterized to better account for various characteristics influencing emission and impact patterns under tropical conditions using best available data and knowledge. Further research is urgently required to improve our knowledge and data with respect to understanding and evaluating pesticide emission and impact processes under tropical conditions.

International audience; The rivers of Guadeloupe and Martinique (French West Indies) show high levels of chlordecone (CLD) contamination. This persistent molecule has a dramatic impact on both aquatic ecosystems and human health. In these rivers, epilithic biofilms are the main endogenous primary producers and represent a central food source for fish and crustaceans. Recently, their viscoelastic properties have been shown to be effective in bio-assessing pollution in tropical environments. As these properties are closely related to the biochemical composition of the biofilms, biochemical (fatty acids, pigments, extracellular polymeric substances (EPS) monosaccharides) and molecular markers (T-RFLP fingerprints of bacteria, archaea and eukaryotes) were investigated. Strong links between CLD pollution and both biofilm biochemistry and microbial community composition were found. In particular, high levels of CLD were linked with modified exo-polysaccharides corresponding to carbohydrates with enhanced adsorption and adhesion properties. The observed change probably resulted from a preferential interaction between CLD and sugars and/or a differential microbial secretion of EPS in response to the pollutant. These changes were expected to impact viscoelastic properties of epilithic biofilms highlighting the effect of CLD pollution on biofilm EPS matrix. They also suggested that microorganisms implement a CLD scavenging strategy, providing new insights on the role of EPS in the adaptation of microorganisms to CLD-polluted environments.

La révision par l'Union européenne de sa réglementation phytosanitaire est l'occasion unique pour la filière banane de se réinventer. Les menaces qui pèsent sur l'utilisation du mancozèbe par le secteur de la production et de l'exportation pourraient en effet rebattre les cartes à un point tel qu'il pourrait y avoir un avant et un après. Revue de détail par le Cirad de ce monde d'après.

International audience; The RIVAGE project aims to promote the adoption of alternative practices to manage the impacts of diffuse pollution in the Pérou River watershed in Guadeloupe. The objective is to produce and share knowledge on processes, impacts and innovative practices with the actors of the territory. To facilitate results uptake, the project has created a “learning partners school”. The learning partners school is a space for exchanges, a forum, developed around themes related to agricultural diffuse pollution. The concept of learning partners school is built on the theories of popular education and collective learning. The article recalls these theoretical references and uses them in a self-evaluation process of the first results obtained by the learning partners school. The authors draw up lessons and orientations for the future.; Le projet RIVAGE veut favoriser l'adoption de pratiques alternatives pour gérer les impacts de la pollution diffuse dans le bassin versant de la rivière Pérou en Guadeloupe. Son objectif est de produire et partager les connaissances sur les processus, les impacts et les pratiques innovantes avec les acteurs du territoire. Pour faciliter la prise en compte des résultats, le projet a créé une « école-acteurs ». L'école-acteurs est un espace d'échanges autour des thématiques liées à la pollution diffuse agricole. Le concept d'école-acteurs fait référence aux théories d'éducation populaire et d'apprentissage collectif. L'article rappelle ces références théoriques et les utilise dans un processus d'auto-évaluation des premiers résultats obtenus par l'école-acteurs. Les auteurs dressent quelques enseignements et orientations pour le futur.

The increased use of legumes is viewed as a promising option to mitigate climate change, as they are a source of proteins and provide nitrogen to the soil. In this paper, we evaluate a strategy for the increased use of legumes in Europe until 2050 by integrating a large array of food and natural system processes into a consistent modeling framework. Three contrasting scenarios are studied: a supply-side scenario entailing a change in the animal feed mix, a demand-side scenario entailing a shift in human diet, and a combination of the shift in human diet with a reforestation in Europe. We find that mitigated emissions are much higher in the two diet shift scenarios (-231 and -259 MtCO2eq, respectively) than in the supply-side scenario (-10 MtCO2eq). Therefore, the main environmental benefit of legumes is to provide proteins as a substitute for animal products rather than enabling a lower consumption of synthetic fertilizer through increased leguminous nitrogen fixation. Diet shift scenarios require a lower use of lands that can then be used to either reduce intensification or reforest. In the former case, the reduction in emissions concerns almost exclusively non-CO2 emissions, mainly through enteric fermentation and manure management, and occurs largely outside Europe. In the latter case, the livestock sector still represents a substantial share of the emission reduction but is outpaced by CO2 emissions through carbon sequestration. An increase in legume production substantially reduces greenhouse gas emissions from the AFOLU sector only when combined with a change in diet, and its combination with reforestation allows the emission reduction to be relocated to Europe through carbon sequestration. Our study concludes that an increase in legume production accompanied by appropriate measures on both the supply and demand side can be effective in reducing emissions. These results can be used to design the European Commission’s “Farm to Fork” strategy for sustainable food and to support climate-friendly farming practices of the post-2020 European common agricultural policy.

Dans le contexte des Antilles, entre climat très favorable aux adventices et monocultures très dépendantes des intrants, la pression herbicide est importante. En Martinique la pollution par ces molécules, via des mécanismes de transfert fortement spatialisés à l'échelle des bassins versants, dégrade la qualité de l'eau des rivières. Dans ce contexte, la thèse propose, en s'appuyant sur la construction d'une méthode de conception collective originale, des organisations territoriales innovantes pour générer des changements coordonnés dans des systèmes de production agricoles visant à réduire durablement la concentration d'herbicides dans les rivières. La démarche est mise en oeuvre sur un bassin versant particulièrement concerné par la pollution herbicide et combine : un diagnostic du système sociotechnique, une phase d'atelier de conception innovante inspirée de la théorie C-K et une phase visant à évaluer les concepts innovants en simulant leur mise en oeuvre dans un jeu sérieux. Les innovations portent tant sur la répartition spatiale de techniques innovantes sur le territoire du bassin versant que sur les dispositifs, aménagements, organisations à créer pour assurer leur succès et leur durabilité. La thèse s'inscrit à la fois dans une agronomie des territoires et dans une agronomie de la conception innovante.

Overreliance on synthetic insecticides in global agriculture is the outcome of a “pesticide treadmill,” in which insecticideinduced pest resistance development and the depletion of beneficial insect populations aggravate farmers’ pesticide dependencies. Examples of the pesticide treadmill have been witnessed repeatedly over the past seven decades, prompting the question whether the rapid uptake and usage patterns of neonicotinoid insecticides and their associated environmental impact are in accordance with this recurrent phenomenon. We hypothesize a conceptual framework in which treadmills are enforced by enabling or disabling drivers within four domains: pest management decisions at the farm level, characteristics of farming landscapes, science and technology, and societal demands. These drivers then tend to create a self-enforcing pesticide “lock-in.” We then analyze several post-1950s historical case studies with reference to this framework, e.g., those involving sprays of the highly hazardous DDT and methyl-parathion, in which the pesticide treadmill was initiated, sustained, and broken, and compare this with current patterns in neonicotinoid use. Historical case studies further illustrate how treadmills occur in three phases in which (i) a limited number of insecticides are routinely used, (ii) resistance development of pests results in the increased crop injury, prompting increased frequency of applications with a wider range of products, (iii) breaking out of the pesticide “lock-in” by policy change and adoption of alternative technologies that lowered chemical inputs and improved agro-ecosystem functioning. The analysis shows similarities as well as differences between neonicotinoid usage patterns and historic pesticide treadmills, and provides guidance on how to effectively avoid or dismantle pesticide treadmills in global agriculture.

International audience; Background and aims: Agroforestry systems combining trees with crops or pastures have been widely used to reduce water, soil, and nutrient losses and associated water pollution from agricultural lands in both temperate and tropical regions. However, reviews on improvement/efficiency and the scope of such reductions by soil, management, climate, and hydrological processes are limited.Methods: This paper synthesized the available evidence on the reduction in surface runoff, soil erosion, nutrient, and pollutant losses (e.g., herbicides, pesticides, and antibiotics) to quantify the effectiveness of agroforestry systems on water quality improvement based on published studies.Results: On average, agroforestry systems reduced surface runoff, soil, organic carbon, and related nutrient losses by 1–100%, 0–97%, –175–92%, and –265–100%, respectively, with average values of 58%, 65%, 9%, and 50%, respectively. They also lowered herbicide, pesticide, and other pollutant losses by –55–100% (49% on average).Conclusions: Reduction efficiency of agroforestry systems is site-dependent and varies widely depending on different biophysical factors. A comprehensive science-based review is needed to generalize agroforestry design and site adaptability for water and soil conservation where climatic, geographical, ecological, and socio-economic conditions are relatively similar in the world.

International audience; Chlordecone, applied on soils until 1993 to control banana weevil, has polluted water resources in the French West Indies for more than 40 years. At the watershed scale, chlordecone applications were not homogenous, generating a spatial heterogeneity of the pollution. The roles of climate, hydrology, soil, agronomy, and geology on watershed functioning generate a temporal heterogeneity of the pollution. This study questions the interactions between practices and the environment that induce such variability. We analyzed hydrological and water pollution datasets from a 2-year monitoring program on the Galion watershed in Martinique (French West Indies). We conjointly analyzed (i) weekly chlordecone (CLD) concentration monitored on 3 river sampling sites, (ii) aquifer piezometric dynamics and pollutions, and (iii) agricultural practices on polluted soils. Our results showed that chlordecone pollution in surface waters are characterized by annual trends and infra-annual variations. Aquifers showed CLD concentration 10 times higher than surface water, with CLD concentration peaks during recharge events. We showed strong interactions between rainfall events and practices on CLD pollution requiring a systemic management approach, in particular during post-cyclonic periods. Small sub-watershed with high CLD pollution appeared to be a substantial contributor to CLD mass transfers to the marine environment via rivers and should therefore receive priority management. We suggest increasing stable organic matter return to soil as well as external input of organic matter to reduce CLD transfers to water. We identified hydrological conditions-notably drying periods-and tillage as the most influential factors on CLD leaching. In particular, tillage acts on 3 processes that increases CLD leaching: organic matter degradation, modification of water paths in soil, and allophane clay degradation.

International audience; In the French West Indies, the chlordecone (organochloride pesticide) pollution is now diffuse becoming new contamination source for crops and environment (water, trophic chain). Decontamination by bioremediation and chemical degradation are still under development but the physical limitations of these approaches are generally not taken into account. These physical limitations are related to the poor physical accessibility to the pesticides in soils because of the peculiar structural properties of the contaminated clays (pore volume, transport properties, permeability, and diffusion). Some volcanic soils (andosols), which represent the half of the contaminated soils in Martinique, contain nanoclay (allophane) with a unique structure and porous properties. Andosols are characterized by pore size distribution in the mesoporous range, a high specific surface area, a large pore volume, and a fractal structure. Our hypothesis is that the clay microstructure characteristics are crucial physico-chemical factors strongly limiting the remediation of the pesticide. Our results show that allophane microstructure (small pore size, hierarchical microstructure, and tortuosity) favors accumulation of chlordecone, in andosols. Moreover, the clay microporosity limits the accessibility of microorganisms and chemical species able to decontaminate because of poor transport properties (permeability and diffusion). We model the transport properties by two approaches: (1) we use a numerical model to simulate the structure of allophane aggregates. The algorithm is based on a cluster-cluster aggregation model. From the simulated data, we derived the pore volume, specific surface area, tortuosity, permeability, and diffusion. We show that transport properties strongly decrease because of the presence of allophane. (2) The fractal approach. We characterize the fractal features (size of the fractal aggregate, fractal dimension, tortuosity inside allophane aggregates) and we calculate that transport properties decrease of several order ranges inside the clay aggregates. These poor transport properties are important parameters to explain the poor accessibility to pollutants in volcanic soils and should be taken into account by future decontamination process. We conclude that for andosols, this inaccessibility could render inefficient some of the methods proposed in the literature.

L'utilisation abusive des pesticides sur les légumes constitue des sources potentielles de contamination pour les consommateurs et l'environnement. La présente étude a été initiée pour caractériser les pratiques de traitements phytosanitaires des cultures maraîchères et les risques sanitaires et environnementaux liés à l'usage des pesticides. Une enquête a été réalisée auprès de 47 producteurs maraîchers dans les bas-fonds de Bamadougou et de Doumanaba dans la région de Sikasso pour caractériser leurs pratiques. Des échantillons d'eau d'irrigation, de sol, de produits végétaux et de pesticides ont été prélevés et analysés pour déterminer les teneurs en résidus de pesticides et de matières actives. Les résultats ont montré que les chenilles étaient les bio-agresseurs les plus importants et que la lutte chimique était la plus utilisée contre ces nuisibles. Il ressort de nos résultats de l'utilisation de ATTAKAN C 344 SE (insecticide du cotonnier) sur les cultures maraîchères, de l'emploi de formulation EC pour le traitement des semences et de la réutilisation des emballages vides. Les teneurs en matières actives détectées étaient nettement inférieures à celles déclarées sur l'étiquette pour ATTAKAN C 344 SE utilisé sur la tomate dans le bas-fond de Doumanaba. Outre les matières actives des deux formulations commerciales (ATTAKAN C 344 SE et LAMBDA SUPER 2,5 EC) utilisées l'année de l'étude par deux exploitants maraîchers, les résidus d'autres substances ont été détectés. Il s'agit de l'Heptachlore dans l'eau d'arrosage à Ziguéna, du Lindane dans le sol à Ziguéna et à Bamadougou, de la Perméthrine dans le sol à Bamadougou et du Chlorothalonil dans le sol à Ziguéna. Les mauvaises utilisations révélées par les enquêtes et les résultats d'analyse au laboratoire sont des indicateurs qui témoignent des risques pour les consommateurs et l'environnement.

International audience; Plants were sampled from four different types of chlordecone-contaminated land in Guadeloupe (West Indies). The objective was to investigate the importance of biological and agri-environmental parameters in the ability of plants to bioaccumulate chlordecone. Among the plant traits studied, only the growth habit significantly affected chlordecone transfer, since prostrate plants concentrated more chlordecone than erect plants. In addition, intensification of land use has led to a significant increase in the amount of chlordecone absorbed by plants. The use of Bayesian networks uncovers some hypothesis and identifies paths for reflection and possible studies to identify and quantify relationships that explain our data.

This article contributes to unraveling the 'paradox of scientific authority', that is, the fact that despite the loss of authority of scientific expertise, policymakers still resort to expert advice. Re-examining the role ascribed to expert assessment in the policy-making process in controversial contexts in particular, the article succeeds in demonstrating that one of the crucial roles of expert evaluation is to establish a more compelling definition of the problem to be dealt with by policymakers. Taking the scientific controversy surrounding the proliferation of green algal bloom on Brittany beaches (France) as a case in point, I show that expert assessment conceived as a framing exercise is, however, a two-way process: it is as much about framing for the sake of settling an expert dispute with sound scientific categories than about solving public problems in a sufficiently consensual way, taking into account the distribution of power more generally in society.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU [ADD1_IRSTEA]Hydrosystèmes et risques naturels; International audience; RECOTOX is a cross-cutting initiative promoting an integrated research to respond to the challenges of monitoring, understanding, and mitigating environmental and health impacts of pesticides in agroecosystems. The added value of RECOTOX is to develop a common culture around spatial ecotoxicology including the whole chain of pressure-exposure-impact, while strengthening an integrated network of in natura specifically equipped sites. In particular, it promotes transversal approaches at relevant socioecological system scales, to capitalize knowledge, expertise, and ongoing research in ecotoxicology and, to a lesser extent, environmental toxicology. Thus, it will open existing research infrastructures in environmental sciences to research programs in ecotoxicology of pesticides.

Background: Reducing the risks and impacts of pesticide use on human health and on the environment is one of the objectives of the European Commission Directive 2009/128/EC in the quest for a sustainable use of pesticides. This Directive, developed through European national plans such as Ecophyto plan in France, promotes the introduction of innovative cropping systems relying, for example, on integrated pest management. Risk assessment for human health of the overall pesticide use in these innovative systems is required before the introduction of those systems to avoid that an innovation becomes a new problem. Objectives: The objectives of this work were to assess and to compare (1) the human exposure to pesticides used in conventional and innovative cropping systems designed to reduce pesticide needs, and (2) the corresponding risks for human health. Methods: Humans (operator and residents) exposure to pesticides and risks for human health were assessed for each pesticide with the BROWSE model. Then, a method was proposed to represent the overall risk due to all pesticides used in one system. This study considers 3 conventional and 9 associated innovative cropping systems, and 116 plant protection products containing 89 different active substances (i.e. pesticides). Results: The modelling results obtained with BROWSE showed that innovative cropping systems such as low input or no herbicide systems would reduce the risk for human health in comparison to the corresponding conventional cropping systems. On the contrary, BROWSE showed that conservation tillage system would lead to unacceptable risks in the conditions of our study, because of a high number of pesticide applications, and especially of some herbicides. For residents, the dermal absorption was the main exposure route while ingestion was found to be negligible. For operators, inhalation was also a predominant route of exposure. In general, human exposure to pesticides and human health risks were found to be correlated to the treatment frequency index TFI (number of registered doses of pesticides used per hectare for one copping season), confirming the relationship between the reduction of pesticide use and the reduction of risks. Conclusions: Assessment with the BROWSE model helped to identify cropping systems with decreased risks from pesticides for human health and to propose some improvements to the cropping systems by identifying the pesticides that led to unacceptable risks. Keywords: BROWSE model, Human exposure, Plant protection products, Risk assessment, Cropping system

Agriculture greatly impacts water resources due to the high volumes of irrigation water consumed in crop production. Additionally, agricultural activities affect hydrological cycles through land-use changes and soil modifications, which may lead to pollution of water bodies. On a local level, these impacts and specific improvement options can be assessed by risk assessment and integrated water resource management. Modelling the impacts of agriculture on freshwater comprehensively is a difficult task as freshwater can be impacted by water consumption and also by water pollution. These are influenced by direct agricultural activities (e.g. irrigation) as well as by indirect activities for the production of agricultural inputs (e.g. fertilizers, agrochemicals). This chapter looks at modelling the impacts of agriculture on freshwater. Following an introduction, the authors go on to look at modelling in relation to water consumption, water quality and salinization. The chapter also covers soil quality, land use and both geographical and temporal variation. Case studies are also included.

International audience; The honeybee (Apis mellifera) has to cope with multiple environmental stressors, especially pesticides. Among those, the herbicide glyphosate and its main metabolite, the amino-methylphosphonic acid (AMPA), are among the most abundant and ubiquitous contaminant in the environment. Through the foraging and storing of contaminated resources, honey-bees are exposed to these xenobiotics. As ingested glyphosate and AMPA are directly in contact with the honeybee gut microbiota, we used quantitative PCR to test whether they could induce significant changes in the relative abundance of the major gut bacterial taxa. Glyphosate induced a strong decrease in Snodgrassella alvi, a partial decrease of a Gillia-mella apicola and an increase in Lactobacillus spp. abundances. In vitro, glyphosate reduced the growth of S. alvi and G. apicola but not Lactobacillus kunkeei. Although being no bee killer, we confirmed that glyphosate can have sublethal effects on the honeybee microbiota. To test whether such imbalanced microbiota could favor pathogen development, honeybees were exposed to glyphosate and to spores of the intestinal parasite Nosema ceranae. Glyphosate did not significantly enhance the effect of the parasite infection. Concerning AMPA, while it could reduce the growth of G. apicola in vitro, it did not induce any significant change in the honeybee microbiota, suggesting that glyphosate is the active component modifying the gut communities.

Food systems are responsible for up to one-third of anthropogenic greenhouse gas (GHG) emissions. These emissions include carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) and are therefore a major driver of climate change. The environmental pressures on food systems are likely to intensify, as humanity is arguably already operating beyond planetary boundaries. The projection for changes between 2010 and 2050 shows that these pressures will result in an increase of between 80 and 92 percent in GHG emissions in the absence of technological change and other mitigation measures. Apart from being a significant source of GHG emissions, food systems are significantly impacted by climate change. Uneven climate change effects, in combination with differences in adaptation capacity, could exacerbate existing inequalities between High-Income (HI), Low-Income (LI) and Lower Middle-Income (LMI) countries.

A healthy environment is essential for the proper functioning of both natural and cultivated ecosystems and, as such, plays a major role in food systems. Many different sources, including the agricultural sector itself, emit and accumulate pollutants in different environmental compartments (soil, water and air). When there are excessive pollutant levels, ecological functioning is hampered by eroded biodiversity, disrupted nutrient cycling, toxicity and depleted soil fertility, and can lead to reduced yields and contaminated food products. Many pollutants end up in water through leaching and run-off and have negative impacts on aquatic ecosystems, reducing fish and seafood stocks. Pollutants can also contaminate the food chain and cause food toxicity risks, and this is particularly true when pollutants undergo gradual biological concentration along the food chain.

International audience; Non-point source pollution is a cause of major concern within the European Union. This is reflected in increasing public and political focus on a more sustainable use of pesticides, as well as a reduction in diffuse pollution. Climate change will likely to lead to an even more intensive use of pesticides in the future, affecting agriculture in many ways. At the same time, the Water Framework Directive (WFD) and associated EU policies called for a “good” ecological and chemical status to be achieved for water bodies by the end of 2015, currently delayed to 2021–2027 due to a lack of efficiency in policies and timescale of resilience for hydrosystems, especially groundwater systems. Water managers need appropriate and user-friendly tools to design agro-environmental policies. These tools should help them to evaluate the potential impacts of mitigation measures on water resources, more clearly define protected areas, and more efficiently distribute financial incentives to farmers who agree to implement alternative practices. At present, a number of reports point out that water managers do not use appropriate information from monitoring or models to make decisions and set environmental action plans. In this paper, we propose an integrated and collaborative approach to analyzing changes in land use, farming systems, and practices and to assess their effects on agricultural pressure and pesticide transfers to waters. The integrated modeling of agricultural scenario (IMAS) framework draws on a range of data and expert knowledge available within areas where a pesticide action plan can be defined to restore the water quality, French “Grenelle law” catchment areas, French Water Development and Management Plan areas, etc. A so-called “reference scenario” represents the actual soil occupation and pesticide-spraying practices used in both conventional and organic farming. A number of alternative scenarios are then defined in cooperation with stakeholders, including socio-economic conditions for developing alternative agricultural systems or targeting mitigation measures. Our integrated assessment of these scenarios combines the calculation of spatialized environmental indicators with integrated bio-economic modeling. The latter is achieved by a combined use of Soil and Water Assessment Tool (SWAT) modeling with our own purpose-built land use generator module (Generator of Land Use version 2 (GenLU2)) and an economic model developed using General Algebraic Modeling System (GAMS) for cost-effectiveness assessment. This integrated approach is applied to two embedded catchment areas (total area of 360,000 ha) within the Charente river basin (SW France). Our results show that it is possible to differentiate scenarios based on their effectiveness, represented by either evolution of pressure (agro-environmental indicators) or transport into waters (pesticide concentrations). By analyzing the implementation costs borne by farmers, it is possible to identify the most cost-effective scenarios at sub-basin and other aggregated levels (WFD hydrological entities, sensitive areas). Relevant results and indicators are fed into a specifically designed database. Data warehousing is used to provide analyses and outputs at all thematic, temporal, or spatial aggregated levels, defined by the stakeholders (type of crops, herbicides, WFD areas, years), using Spatial On-Line Analytical Processing (SOLAP) tools. The aim of this approach is to allow public policy makers to make more informed and reasoned decisions when managing sensitive areas and/or implementing mitigation measures.

International audience; Purpose Salinisation is a threat not only to arable land but also to freshwater resources. Nevertheless, salinisation impacts have been rarely and only partially included in life cycle assessment (LCA) so far. The objectives of this review paper were to give a comprehensive overview of salinisation mechanisms due to human interventions, analyse the completeness, relevance and scientific robustness of existing published methods addressing salinisation in LCA and provide recommendations towards a comprehensive integration of salinisation within the impact modelling frameworks in LCA.Methods First, with the support of salinisation experts and related literature, we highlighted multiple causes of soil and water salinisation and presented induced effects on human health, ecosystems and resources. Second, existing life cycle impact assessment (LCIA) methods addressing salinisation were analysed against the International Reference Life Cycle Data System analysis grid of the European Commission. Third, adopting a holistic approach, the modelling options for salinisation impacts were analysed in agreement with up-to-date LCIA frameworks and models.Results and discussion We proposed a categorisation of salinisation processes in four main types based on salinisation determinism: land use change, irrigation, brine disposal and overuse of a water body. For each salinisation type, key human management and biophysical factors involved were identified. Although the existing methods addressing salinisation in LCA are important and relevant contributions, they are often incomplete with regards to both the salinisation pathways they address and their geographical validity. Thus, there is a lack of a consistent framework for salinisation impact assessment in LCA. In analysing existing LCIA models, we discussed the inventory and impact assessment boundary options. The land use/land use change framework represents a good basis for the integration of salinisation impacts due to a land use change but should be completed to account for off-site impacts. Conversely, the land use/land use change framework is not appropriate to model salinisation due to irrigation, overuse of a water body and brine disposal. For all salinisation pathways, a bottom-up approach describing the environmental mechanisms (fate, exposure and effect) is recommended rather than an empirical or top-down approach because (i) salts and water are mobile and theirs effects are interconnected; (ii) water and soil characteristics vary greatly spatially; (iii) this approach allows the evaluation of both on-and off-site impacts and (iv) it is the best way to discriminate systems and support a reliable eco-design.Conclusions This paper highlights the importance of including salinisation impacts in LCA. Much research effort is still required to include salinisation impacts in a global, consistent and operational manner in LCA, and this paper provides the basis for future methodological developments.

Description du sujet. Le maraichage est particulièrement développé au sein de l’agriculture urbaine et périurbaine dans la région de Dakar. L’application répétée de matières organiques dans ces agrosystèmes engendre sur le long terme de forts apports d’éléments traces métalliques (ETM).Objectifs. L’objectif est de diagnostiquer la contamination en ETM de ces agrosystèmes.Méthode. Pour quatre sites, nous comparons les teneurs en Cu, Zn, Pb et Cd des parcelles cultivées depuis longtemps et des parcelles connexes non cultivées, dans les couches de sol travaillées et en profondeur. Résultats. Les deux types de sols présents (Arénosol et Fluvisol) sont caractérisés par des fonds pédogéochimiques en ETM significativement différents. Dans les couches de sol 0-20 et 20-40 cm des quatre sites étudiés, les teneurs en ETM sont significativement plus élevées (p, Diagnosis of periurban Dakar (Senegal) agrosystem contamination by trace elementsDescription of the subject. Urban and periurban market gardening is widespread in the Dakar area of Senegal. Repeated long-term application of organic matter results in high inputs of trace elements (TE).Objectives. The aim is to assess TE contamination in suburban agrosystems.Method. At four sites, we compared the Cu, Zn, Pb and Cd content in the surface layers and sublayers of plots cultivated over a long period with the content found in adjacent uncultivated plots.Results. The two prevailing soil types (Arenosol and Fluvisol) were characterized by significantly different background soil geochemical TE content. In the 0 – 20 and 20 – 40 cm soil layers at the four studied sites, TE content was significantly higher (p

International audience; Some volcanic soils like andosols contain short-range order nanoclays (allophane) which build aggregates with a tortuous and fractal microstructure. The aim of the work was to study the influence of the microstructure and mesoporosity of the allophane aggregates on the pesticide chlordecone retention in soils. Our study shows that the allo-phane microstructure favors pollutants accumulation and se-questration in soils. We put forth the importance of the meso-porous microstructure of the allophane aggregates for pollutant trapping in andosols. We show that the soil contamination increases with the allophane content but also with the mesopore volume, the tortuosity, and the size of the fractal aggregate. Moreover, the pore structure of the allophane aggregates at nanoscale favors the pesticide retention. The fractal and tortuous aggregates of nanoparticles play the role of nanolabyrinths. It is suggested that chlordecone storage in allophanic soils could be the result of the low transport properties (permeability and diffusion) in the allophane aggregates. The poor accessibility to the pesticide trapped in the mesopore of allophane aggregates could explain the lower pollutant release in the environment.

International audience; Faced with health, environmental, and socio-economic issues related to the heavy use of pesticides, diffuse phytosanitary pollution becomes a major concern shared by all the field actors. These actors, namely the farmers and territorial managers, have expressed the need to implement decision support tools for the territorial management of diffuse pollution resulting from the plant protection practices and their impacts. To meet these steadily increasing requests, a cartographic analysis approach was implemented based on GIS which allows the spatialization of the diffuse pollution impacts related to plant protection practices on the Etang de l’Or catchment area in the South of France. Risk mapping represents a support-decision tool that enables the different field actors to identify and locate vulnerable areas, so as to determine action plans and agri-environmental measures depending on the context of the natural environment. This work shows that mapping is helpful for managing risks related to the use of pesticides in agriculture by employing indicators of pressure (TFI) and risk on the applicator’s health (IRSA) and on the environment (IRTE). These indicators were designed to assess the impact of plant protection practices at various spatial scales (field, farm, etc.). The cartographic analysis of risks related to plant protection practices shows that diffuse pollution is unequally located in the North (known for its abundant garrigues and vineyards) and in the South of the Etang de l’Or catchment area (the Mauguio-Lunel agricultural plain known for its diversified cropping systems). This spatial inequity is essentially related to land use and agricultural production system. Indeed, the agricultural lands cover about 60% of the total catchment area. Consequently, this cartographic analysis helps the territorial actors with the implementation of strategies for managing risks of diffuse pollution related to pesticides use in agriculture, based on environmental and socio-economic issues and the characteristics of the natural environment.

Synthesis note. ENPARD South initiative (European Commission)

Chlordecone, an organochlorine insecticide, continues to pollute soils in the French West Indies. The main source of human exposure to this pollutant is food. Root vegetables, which are staple foods in tropical regions, can be highly contaminated and are thus a very effective lever for action to reduce consumer exposure. We analyzed chlordecone contamination in three root vegetables, yam, dasheen and sweet potato, which are among the main sources of chlordecone exposure in food in the French West Indies. All soil types do not have the same potential for the contamination of root vegetables, allophanic andosols being two to ten times less contaminating than non-allophanic nitisols and ferralsols. This difference was only partially explained by the higher OC content in allophanic soils. Dasheen corms were shown to accumulate more chlordecone than yam and sweet potato tubers. The physiological nature of the root vegetable may explain this difference. Our results are in good agreement with the hypothesis that chlordecone uptake by root vegetables is based on passive and diffusive processes and limited by transport and dilution during growth.