Dynamique du piégeage des micropolluants métalliques au sein des zones humides artificielles traitant des eaux pluviales urbaines strictes : Etude de cas à Strasbourg, Moulins-lès-Metz et Leuville-sur-Orge

Colloque avec actes et comité de lecture. internationale.International audienceStormwater constructed wetlands (SCW) in Strasbourg (Alsace, France), Moulin-lès-Metz (Lorraine, France), and Leuville-sur-Orge (Ile-de-France, France) receive and treat exclusively runoffs from urban catchments but with different soil uses. Made up of sedimentation ponds and a vertical subsurface flow constructed wetland, the treatment facilities lead to trap several trace metal pollution. Each site belongs to different hydroclimatic areas (modified oceanic, modified continental and semi-continental) and was designed for different purposes (watercourse protection in Strasbourg and in Leuville-sur-Orge, protection of drinking water wells in Moulins-lès-Metz). The aim of this study is to explore trace metals (Cd, Cu, Pb and Zn) behaviours in these SCW. We investigated trace metal trapping by determining concentrations in the systems compartments (filters media and plants). Then trace metal speciation was determined through sequencial extractions of the sediment and filter media. This allowed to determine their forms in soils and to anticipate their behaviour during physical and chemical condition changes. This study permits to obtain first results for the metals stability, to highlight a decrease of the concentrations through the SCW depth (from surficial sediment to clean filter media) and to observe a negligible metal trap in plants (mainly in roots)

The Three-Dimensional Distribution of αA-Crystalline in Rat Lenses and Its Possible Relation to Transparency

Lens transparency depends on the accumulation of massive quantities (600–800 mg/ml) of twelve primary crystallines and two truncated crystallines in highly elongated “fiber” cells. Despite numerous studies, major unanswered questions are how this heterogeneous group of proteins becomes organized to bestow the lens with its unique optical properties and how it changes during cataract formation. Using novel methods based on conical tomography and labeling with antibody/gold conjugates, we have profiled the 3D-distribution of the αA-crystalline in rat lenses at ∼2 nm resolutions and three-dimensions. Analysis of tomograms calculated from lenses labeled with anti-αA-crystalline and gold particles (∼3 nm and ∼7 nm diameter) revealed geometric patterns shaped as lines, isosceles triangles and polyhedrons. A Gaussian distribution centered at ∼7.5 nm fitted the distances between the ∼3 nm diameter gold conjugates. A Gaussian distribution centered at ∼14 nm fitted the Euclidian distances between the smaller and the larger gold particles and another Gaussian at 21–24 nm the distances between the larger particles. Independent of their diameters, tethers of 14–17 nm in length connected files of gold particles to thin filaments or clusters to ∼15 nm diameter “beads.” We used the information gathered from tomograms of labeled lenses to determine the distribution of the αA-crystalline in unlabeled lenses. We found that αA-crystalline monomers spaced ∼7 nm or αA-crystalline dimers spaced ∼15 nm center-to-center apart decorated thin filaments of the lens cytoskeleton. It thus seems likely that lost or gain of long-range order determines the 3D-structure of the fiber cell and possible also cataract formation

A new empirical law to accurately predict solute retention capacity within horizontal flow constructed wetlands

International audienc

Large scale micropollutants and lipids screening in the sludge layers and the ecosystem of a vertical flow constructed wetland

International audienc