title: Zn Speciation and Stable Isotope Fractionation in a Contaminated Urban Wetland Soil-Typha latifolia System.
abstract: Wetlands play a key role in the immobilization of metallic contaminants. In this context the mechanisms of Zn sequestration and Zn transfer and storage in Typha latifolia L. colonizing a frequently flooded contaminated soil were studied. A combination of EXAFS spectroscopy, micro X-ray fluorescence (μXRF) and Zn isotope measurements was applied to soil, plant organs and decaying biomass. Zn was present in the soil as Zn-layered double hydroxide, as tetrahedral and octahedral sorbed Zn species, and as ZnS. Octahedral and tetrahedral Zn (attributed to symplastic Zn-organic acid and apoplasmic Zn-cell wall complexes, respectively) and Zn-thiol species were observed in the roots, rhizomes and stems. Iron plaque was present on the rhizomes and roots. Enrichment in light isotopes for Zn sorbed on the plaque relative to the soil (Δ66Znplaque-soil= -0.3 to -0.1‰) suggested the dissolution of ZnS (enriched in light isotopes) in the rhizosphere with subsequent Zn2+sorption on the root plaque. Furthermore, enrichment in light isotopes of stems relative to leaves (Δ66Znstem-leaves= -0.2‰) suggested the remobilization of Zn via the phloem, from leaves back to the stems. Overall these data highlight the role of thiols in controlling Zn speciation during its transfer and storage in T. latifolia.
authors.affiliation: Université de Lyon, Université Lyon 1, ENS de Lyon, CNRS, UMR 5276 LGL-TPE, F-69622 Villeurbanne, France.
authors.forename: Anne-Marie
authors.identifier: http://orcid.org/0000-0002-8992-3658
authors.initials: AM
authors.lastname: Aucour
authors.affiliation: Université de Lyon, ENTPE, CNRS, UMR 5023 LEHNA, 2 Rue Maurice Audin F-69518 Vaulx-en-Velin, France.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Bedell
authors.affiliation: Université de Lyon, ENTPE, CNRS, UMR 5023 LEHNA, 2 Rue Maurice Audin F-69518 Vaulx-en-Velin, France.
authors.forename: Marine
authors.initials: M
authors.lastname: Queyron
authors.affiliation: Université de Lyon, ENTPE, CNRS, UMR 5023 LEHNA, 2 Rue Maurice Audin F-69518 Vaulx-en-Velin, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Tholé
authors.affiliation: Université de Lyon, ENS de Lyon, Université Lyon 1, CNRS, UMR 5276 LGL-TPE, F-69364 Lyon Cedex 7, France.
authors.forename: Aline
authors.initials: A
authors.lastname: Lamboux
authors.affiliation: ISTerre, Université Grenoble Alpes, CNRS, F-38058 Grenoble, France.
authors.forename: Géraldine
authors.initials: G
authors.lastname: Sarret
mesh_terms: D007554:Isotopes; D018517:Plant Roots; D012987:Soil; D032401:Typhaceae; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D053833:Wetlands; D015032:Zinc / Q000737:chemistry*
chemical_list: D007554:Isotopes; D012987:Soil; D014874:Water Pollutants, Chemical; D015032:Zinc