title: Fate of cadmium in the rhizosphere of Arabidopsis halleri grown in a contaminated dredged sediment.
abstract: In regions impacted by mining and smelting activities, dredged sediments are often contaminated with metals. Phytotechnologies could be used for their management, but more knowledge on the speciation of metals in the sediment and on their fate after colonization by plant roots is needed. This work was focused on a dredged sediment from the Scarpe river (North of France), contaminated with Zn and Cd. Zn, Cd hyperaccumulating plants Arabidopsis halleri from metallicolous and non-metallicolous origin were grown on the sediment for five months in a pot experiment. The nature and extent of the modifications in Cd speciation with or without plant were determined by electron microscopy, micro X-ray fluorescence and bulk and micro X-ray absorption spectroscopy. In addition, changes in Cd exchangeable and bioavailable pools were evaluated, and Cd content in leachates was measured. Finally, Cd plant uptake and plant growth parameters were monitored. In the original sediment, Cd was present as a mixed Zn, Cd, Fe sulfide. After five months, although pots still contained reduced sulfur, Cd-bearing sulfides were totally oxidized in vegetated pots, whereas a minor fraction (8%) was still present in non-vegetated ones. Secondary species included Cd bound to O-containing groups of organic matter and Cd phosphates. Cd exchangeability and bioavailability were relatively low and did not increase during changes in Cd speciation, suggesting that Cd released by sulfide oxidation was readily taken up with strong interactions with organic matter and phosphate ligands. Thus, the composition of the sediment, the oxic conditions and the rhizospheric activity (regardless of the plant origin) created favorable conditions for Cd stabilization. However, it should be kept in mind that returning to anoxic conditions may change Cd speciation, so the species formed cannot be considered as stable on the long term.
authors.affiliation: ISTerre, Université Grenoble Alpes, CNRS, F-38041 Grenoble, France; Laboratoire de Chimie Analytique Bio-Inorganique et Environnement (LCABIE), Institut des sciences analytiques et de physico-chimie pour l'environnement et les matériaux (IPREM UMR 5254), Université de Pau et des Pays de l'Adour and CNRS, Hélioparc, 2 Av. Pierre Angot, 64053 Pau Cedex 9, France; INERIS, Parc technologique Alata, 60550 Verneuil-en-Halatte, France; EMDouai, MPE-GCE, 930 Boulevard Lahure, 59500 Douai, France. Electronic address: huguet.st@gmail.com.
authors.forename: Séphanie
authors.initials: S
authors.lastname: Huguet
authors.affiliation: Laboratoire de Chimie Analytique Bio-Inorganique et Environnement (LCABIE), Institut des sciences analytiques et de physico-chimie pour l'environnement et les matériaux (IPREM UMR 5254), Université de Pau et des Pays de l'Adour and CNRS, Hélioparc, 2 Av. Pierre Angot, 64053 Pau Cedex 9, France.
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Isaure
authors.affiliation: INERIS, Parc technologique Alata, 60550 Verneuil-en-Halatte, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Bert
authors.affiliation: EMDouai, MPE-GCE, 930 Boulevard Lahure, 59500 Douai, France.
authors.forename: Agnès
authors.initials: A
authors.lastname: Laboudigue
authors.affiliation: OSUG, UMS832 CNRS/UJF, 414 rue de la piscine, 38400 Saint-Martin d'Hères, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Proux
authors.affiliation: Beamline LUCIA, SLS, Swiss Light Source, CH-5232 Villigen, Switzerland; Synchrotron SOLEIL, F-91192 Gif Sur Yvette, France.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Flank
authors.affiliation: Beamline LUCIA, SLS, Swiss Light Source, CH-5232 Villigen, Switzerland; Synchrotron SOLEIL, F-91192 Gif Sur Yvette, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Vantelon
authors.affiliation: ISTerre, Université Grenoble Alpes, CNRS, F-38041 Grenoble, France. Electronic address: geraldine.sarret@ujf-grenoble.fr.
authors.forename: Géraldine
authors.initials: G
authors.lastname: Sarret
mesh_terms: D017360:Arabidopsis / Q000254:growth & development*; D002104:Cadmium / Q000032:analysis*; D005602:France; D019015:Geologic Sediments / Q000382:microbiology*; D008956:Models, Chemical; D058441:Rhizosphere; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D012989:Soil Pollutants; D002104:Cadmium
keywords: Arabidopsis halleri; Cadmium (Cd); DGT; EXAFS; Leachates; Phytoavailability; SEM–EDS; Sediment; Speciation; μXANES; μXRF