LONG-TERM stability of arsenic in iron amended contaminated soil
2021
Kumpiene, Jurate | Carabante, Ivan | Kasiuliene, Alfreda | Austruy, Annabelle | Mench, Michel | Luleå University of Technology = Luleå Tekniska Universitet (LUT) | Institut Ecocitoyen pour la Connaissance des Pollutions [Fos-sur-Mer] | Biodiversité, Gènes & Communautés (BioGeCo) ; Université de Bordeaux (UB)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | The La Combe de Saut experiment was funded by ADEME and the LIFE project DIFPOLMINE. The Reppel experiment was set up under the EU FP5 Phytorehab project. Experiments in Sweden were financed by the Swedish Research Council FORMAS and European Union Structural Funds and New Objective 1, North Sweden Soil Remediation Center (MarksaneringsCentrum Norr - MCN). Stanford Synchrotron Radiation Lightsource is acknowledged for granting our beamtime proposal (4663) under which X-Ray absorption measurements presented in this work were performed.
International audience
显示更多 [+] 显示较少 [-]英语. This study aimed at elucidating the long-term efficiency of soil remediation where chemical stabilization of arsenic (As) contaminated soil using zerovalent iron (Fe) amendments was applied. A combination of chemical extraction and extended X-Ray absorption fine structure (EXAFS) spectroscopy technique was applied on soils collected from five laboratory and field experiments in Sweden and France. All soils were treated with 1 wt% of zerovalent Fe grit 2e15 years prior to the sampling. The results indicate that all studied soils, despite the elapsed time since their amendment with Fe grit, had substantial amounts of ferrihydrite and/or lepidocrocite. These metastable and the most reactive Fe (oxyhydr)oxides (mainly ferrihydrite) were still present in substantial amounts even in the soil that was treated 15 years prior to the sampling and contributed most to the As immobilisation in the amended soils. This increases confidence in the long-term efficiency of As immobilisation using zerovalent Fe amendments. Both applied methods, sequential extraction and EXAFS, were in line for most of the samples in terms of their ability to highlight As immobilisation by poorly crystalline Fe phases.
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