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Les zones humides mediterraneennes sont au cœur de multiples enjeux environnementaux. Les zones humides de la Palun connectees a l’etang de Berre sont une zone speciale de conservation situee a l’aval d’un bassin versant anthropise. Une contamination diffuse et cumulative dans le temps des sediments y a ete identifiee. C’est dans ce contexte qu’un travail a ete mene sur un procede de traitement des eaux du bassin versant de la Palun pour favoriser la resilience du marais recepteur face a la pollution chronique. Les possibilites de realisation d’une zone humide artificielle en amont du marais, dediee a l’epuration des eaux, ont ete reflechies en lien avec les usages et les attentes parfois divergentes des acteurs du territoire. La reparation des atteintes environnementales dans le contexte socio-economique contraint de l’etang de Berre a ete interrogee a partir des savoirs issus de l’ecologie de la restauration et de la sociologie.

International audience; Industrial effluents discharged into the environment may have ecotoxic effects even if they come up to regulatory standards. Chemical evaluation of treatment performance by end-of-pipe treatment systems is thus not sufficient, especially when mixtures of metallic and organic contaminants are concerned. Given that contamination may alter biological characteristics of the environment, biomonitoring studies may provide information on integrated ecotoxical effects. However, there is a need for bioassays purpose-designed for direct use at industrial sites. Many biomonitoring tools already exist and have been proved to be efficient for evaluating the ecotoxicity of contaminated waters, but most of them require laboratory equipment. In this study, an experiment in microcosms under controlled conditions of pollution was carried out to assess the morphological responses of five helophytes exposed to mixtures of organic and/or metallic pollutants. The criteria of plant growth and development, i.e. aerial elongation and leaf senescence, that were the most relevant for reflecting the ecotoxicity of contaminant mixtures and that could be monitored on-site with a user-friendly method, were then selected. Focusing on these selected criteria, a new bioindicator tool, named the Helophyte Development Index (HDI), was created. Our results suggest that the HDI is a promising tool to use on-site for assessing the ecological state of waters released in aquatic environment by industrial factories, following the recommendations of the European Water Agency. (C) 2015 Elsevier B.V. All rights reserved.

International audience; Various industrial processes and anthropogenic activities in urban areas induce a release of metals, metalloids and organic pollutants. Phytoremediation of co-contaminated waters in constructed wetlands is a promising solution for reducing the impact on natural environments. In order to improve the design and management of constructed wetlands, more knowledge is needed concerning the effect of organic pollutants on plant metal and metalloid uptake. In this study, the effects of a mixture of organic pollutants commonly found in industrial effluents (hydrocarbons, polycyclic aromatic hydrocarbons, anionic detergent) on the uptake of ten metals and metalloids (MM), i.e. Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn, by five helophytes having a wide European distribution were studied. Main effects of plant species and pollutant conditions on metal uptake and interactions between factors were determined by a statistical treatment of a microcosm experiment. Overall, the order of element uptake in plants was Fe > Al > Mn > Cr, Ni, Zn, > Cu > As, Cd, Pb, which was consistent with relative concentrations in the rhizosphere environment of microcosms. Larger amounts of metals were retained in belowground biomass of plants than in aboveground parts. Statistical analysis showed that organic pollutants enhanced the accumulation of Mn in whole plants and the retention of Fe in belowground parts, while they reduced the accumulation of Cd, Ni, and Zn in whole plants and the retention of Cu in belowground parts. For the other MM (Al, As, Cr, Pb), effects were variable, depending on the plant species. Among the five plants tested, Carex cuprina generally removed the highest quantities of MM, which was the result of both a high metal accumulation capacity and high biomass production. Nevertheless, no significant proportion of the MM total loading could be removed in plants aboveground parts. (C) 2014 Elsevier Ltd. All rights reserved.

In the Mediterranean area, surface waters often have low discharge or renewal rates, hence metal contamination from industrialised catchments can have a high negative impact on the physico-chemical and biological water quality. In a context of climate and anthropological changes, it is necessary to provide an integrative approach for the prevention and control of metal pollution, in order to limit its impact on water resources, biodiversity, trophic network and human health. For this purpose, introduction of constructed wetlands (CWs) between natural aquatic ecosystems and industrialised zones or catchments is a promising strategy for eco-remediation. Analysis of the literature has shown that further research must be done to improve CW design, selection and management of wetland plant species and catchment organisation, in order to ensure the effectiveness of CWs in Mediterranean environments. Firstly, the parameters of basin design that have the greatest influence on metal removal processes must be identified, in order to better focus rhizospheric processes on specific purification objectives. We have summarised in a single diagram the relationships between the design parameters of a CW basin and the physico-chemical and biological processes of metal removal, on the basis of 21 mutually consistent papers. Secondly, in order to optimise the selection and distribution of helophytes in CWs, it is necessary to identify criteria of choice for the plant species that will best fit the remediation objectives and environmental and economic constraints. We have analysed the factors determining plant metal uptake efficiency in CWs on the basis of a qualitative meta-analysis of 13 studies with a view to determine whether the part played by metal uptake by plants is relevant in comparison with the other removal processes. Thirdly, we analysed the parameters to consider for establishing suitable management strategies for CWs and how they affect the whole CW design process. Finally, we propose monitoring and policy measures to facilitate the integration of CWs within Mediterranean industrialised catchments. Keywords: Constructed wetlands, Metal pollution, Plant species selection, Design methodologies, Management strategies, Industrialized Mediterranean Catchments

International audience; Les macrophytes sont de plus en plus exploités pour atteindre les bons états chimique et écologique recommandés des masses d’eau européennes. Mais quelles sont les particularités des macrophytes en tant qu’outil de bio-surveillance ? Et quelles nouvelles informations sont apportées par la recherche quant à leur potentiel de réduction d’écotoxicité ?