International audience | This study evaluates the efficiency of two small constructed wetlands installed in the regulatory grass strips between a drained plot and a river. The observed nitrate removal efficiencies were independent of the season or type of constructed wetland and ranged from 5.4 to 10.9% of the inlet amounts. The pesticide mass budgets ranged from −618.5 to 100%, depending on the molecule. The negative efficiencies were attributed to runoff and remobilization. In contrast, the highest efficiencies were associated with pesticides with high Koc and low DT50 (half-life) values, suggesting sorption and degradation. However, the effectiveness of these wetlands is limited for pesticides with low Koc or high DT50 values; thus, the use of these molecules must be reduced. Increasing the number of these small, inexpensive and low-maintenance wetlands in the agricultural landscape would reduce the level of water pollution whilst preserving the extent of cultivated land, but their long-term effectiveness should be evaluated.

Les niveaux de concentration des pesticides dans l’atmosphère méritent une attention particulière de la part de la recherche compte tenu de leurs impacts potentiels sur la population et les écosystèmes. L’activité agricole constitue la principale source de contamination de l’atmosphère par les pesticides. Bien que la volatilisation depuis la plante soit reconnue plus intense et plus rapide que la volatilisation depuis le sol, cette voie de transfert est à ce jour la moins bien renseignée avec peu de modèles disponibles pour sa description. Le manque de connaissances est lié essentiellement à la complexité des interactions entre les processus ayant lieu à la surface de la feuille et qui sont en compétition avec la volatilisation, notamment la pénétration foliaire et la photodégradation. Cet article présente une synthèse bibliographique sur l’état des lieux des connaissances sur le processus de volatilisation des pesticides depuis un couvert végétal, de la pénétration foliaire et de la photodégradation, ainsi que les facteurs de contrôle de ces processus. Les méthodes de mesure ainsi que les modèles existants décrivant ces processus sont également présentés et analysés | The agricultural activity presents the main source of the atmospheric contamination by pesticides. The occurrence of pesticides in the atmosphere concerns the research community due to their potential impacts on population and ecosystems. The volatilization from plants is higher and faster than the volatilization from soil. However, this transfer pathway is difficult to assess with few available models. The lack of knowledge on pesticide volatilization from plants is essentially linked to the complex interactions between processes occurring at the leaf surface and competing with volatilization, such as leaf penetration and photodegradation. This article presents a bibliographic synthesis of the state of knowledge on pesticide volatilization from plants, leaf penetration, photodegradation and control factors of these processes. Measuring methods and existing models describing these processes are also presented and analyzed

Diffuse pollution is a major cause for the degradation of water quality also in the French context. Nitrates and pesticides, mostly from agricultural sources, are the main pollutants. To a lesser extent, diffuse pollution has domestic and collective sources. Nitrate rates remain high in surface waters, despite an improvement of water quality in areas where livestock farming is responsible for nitrate pollution. The contamination of groundwater by nitrates and pesticides has been worsening in the last years. The EU Nitrate Directive is the main regulatory tool for the control of nitrate diffuse pollution. Farmers in designated vulnerable zones have to comply with measures included in action programs. The implementation of the ND in France was evaluated as incomplete relating to insufficient designation of vulnerable zones and non-conformity of action programs. Two other constraints are a low awareness of requirements by farmers and difficulties in controlling and enforcing compliance. As a consequence, the implementation process of the ND was redefined in France, with an extension of vulnerable zones, now covering 55% of agricultural area. While action programs were mainly defined at the district level, now a core program defined at the national level is completed by regional programs established by State regional authorities on the basis of the work of regional technical groups. The development of action plans to protect drinking water catchments relies on cooperation between water suppliers and agricultural stakeholders. A first step is the definition of protection zone(s) in the water catchment. Then, agricultural and non-agricultural pressures are identified. Finally, an action plan is defined to be implemented voluntary by farmers. In the French context, the involvement of water suppliers is fostered by financial incentives provided by Water Agencies. Also the “Grenelle” regulation imposes the definition and implementation of action plans in priority water catchments. The participation of farmers is targeted by a number of tools: (1) mostly agri-environmental schemes funded by EU rural development policy, (2) environmental land leases, (3) the development of market outlets such as local organic supply chains. Research shows that the success of this approach depends on a number of factors. The main success factors identified are: The scale of collective action. With regard with the governance of collective action, the definition of the role of stakeholders involved the involvement of farm leaders and farm organizations and the involvement of agricultural cooperatives and agro-industries. Finally, technical support to local stakeholders (water suppliers, farmers) was identified as a crucial success factor.

National audience

International audience | Poplar is commonly used for phytoremediation of metal polluted soils. However, the high concentrations of trace elements present in leaves may return to soil upon leaf abscission. To investigate the mechanisms controlling leaf metal content, metal concentrations and expression levels of genes involved in metal transport were monitored at different developmental stages on leaves from different poplar genotypes growing on a contaminated field. Large differences in leaf metal concentrations were observed among genotypes. Whereas Mg was remobilized during senescence, Zn and Cd accumulation continued until leaf abscission in all genotypes. A positive correlation between Natural Resistance Associated Macrophage Protein 1 (NRAMP1) expres-sion levels and Zn bio-concentration factors was observed. Principal component analyses of metal concentrations and gene expression levels clearly discriminated poplar genotypes. This study highlights a general absence of trace element remobilization from poplar leaves despite genotype specificities in the control of leaf metal homeostasis.

International audience | The role of polychlorinated biphenyls (PCBs) on exposure-related endocrine effects has been poorlyinvestigated in wild birds. This is the case for stress hormones including corticosterone (CORT). Somestudies have suggested that environmental exposure to PCBs and altered CORT secretion might beassociated. Here we investigated the relationships between blood PCB concentrations and circulatingCORT levels in seven free-ranging polar seabird species occupying different trophic positions, and hencecovering a wide range of PCB exposure. Blood P7PCB concentrations (range: 61e115,632 ng/g lw) werepositively associated to baseline or stress-induced CORT levels in three species and negatively associatedto stress-induced CORT levels in one species. Global analysis suggests that in males, baseline CORT levelsgenerally increase with increasing blood P7PCB concentrations, whereas stress-induced CORT levelsdecrease when reaching high blood P7PCB concentrations. This study suggests that the nature of thePCB-CORT relationships may depend on the level of PCB exposure.

High fertilizer input is necessary to sustain high yields in oil palm agroecosystems, but it may endanger neighboring aquatic ecosystems when excess nutrients are transported to waterways. In this study, the hydrochemical dynamics of groundwater and streams under baseflow conditions were evaluated with bi-monthly measurements for 1 year on 16 watersheds. Hydrochemical measurements were related to the spatial distribution of soil and fertilization practices across a landscape of 100 km2, dominated by oil palm cultivation, in Central Sumatra, Indonesia. The low nutrient concentrations recorded in streams throughout the landscape indicated that the mature oil palm plantations in this study did not contribute to eutrophication of aquatic ecosystems. This was ascribed to high nutrient uptake by oil palm, a rational fertilizer program, and dilution of nutrient concentrations due to heavy rainfall in the study area. Soil type controlled dissolved inorganic N and total P fluxes, with greater losses of N and P from loamy-sand uplands than loamy lowlands. Organic fertilization helped to reduce nutrient fluxes compared to mineral fertilizers. However, when K inputs exceeded the oil palm requirement threshold, high K export occurred during periods when groundwater had a short residence time. For higher nutrient use efficiency in the long term, the field-scale fertilizer management should be complemented with a landscape-scale strategy of fertilizer applications that accounts for soil variability. (Résumé d'auteur)

Growing edible vegetables on Technosols, Firts results of the Agrotechnosol Project. 8th Sino-French Workshop on Soil Pollution and Remediation

New approach to identify and categorize pesticide metabolites in soil combining suspect screening metabolomics with in silico molecular typology. 5th International Conference on Environmental Pollution and Remediation (ICEPR). 5th International Conference on Environmental Pollution and Remediation (ICEPR)

INRA-Onema "Phylogeny and Polluosensitivity" program This work was supported by the INRA-Onema 2013-2014 "Phylogeny and Polluosensitivity" program. The authors thank Marc Collinet and Antoine Gallard for technical assistance. Elsevier sci ltd | International audience | The use of standardized monospecific testing to assess the ecological risk of chemicals implicitly relies on the strong assumption that intraspecific variation in sensitivity is negligible or irrelevant in this context. In this study, we investigated genetic variation in copper sensitivity of the freshwater snail Lymnaea stagnalis, using lineages stemming from eight natural populations or strains found to be genetically differentiated at neutral markers. Copper-induced mortality varied widely among populations, as did the estimated daily death rate and time to 50% mortality (LT50). Population genetic divergence in copper sensitivity was compared to neutral differentiation using the Qs-r-FsT approach. No evidence for homogenizing selection could be detected. This result demonstrates that species-level extrapolations from single population studies are highly unreliable. The study provides a simple example of how evolutionary principles could be incorporated into ecotoxicity testing in order to refine ecological risk assessment. (C) 2015 Elsevier Ltd. All rights reserved.