Laboratoire DEEP (Déchets Eaux Environnement Pollutions - Wastes Water Environment Pollutions) INSA-Lyon, France Iron geochemistry in a contaminated urban soil dedicated to stormwater infjltration by Qiufang ZHAN Supervisors: Cécile Delolme, Gislain Lipeme Kouyi, 28/06/20 Vincent Chatain 19
RESUL TS PRESENTAT PRESENTAT MATERIAL MATERIAL RESUL TS CONCLUSION PERSPEC AND AND TIVE ION OF ION OF AND AND AND SUBJECT SUBJECT METHODS METHODS DISCUSSIO PERSPECTIVE DISCUSSIO 2 N S N Background 1. Might stor m-water runofg be a problem? The major compartments of an urban environment ( Wong et al. 2006 )
RESUL TS PRESENTAT MATERIAL CONCLUSION AND AND ION OF AND SUBJECT METHODS DISCUSSIO PERSPECTIVE 2 N S 2. Where Background does runofg rainwater go? The major compartments of an urban environment ( Wong et al. 2006 )
RESUL TS PRESENTAT MATERIAL CONCLUSION AND AND ION OF AND SUBJECT METHODS DISCUSSIO PERSPECTIVE 3 N S Background Basin combining sedimentation and Sedimentation infjltration basin The type of the basin studied Sedimen Infjltration ts basin
RESUL TS PRESENTAT MATERIAL CONCLUSION AND AND ION OF AND SUBJECT METHODS DISCUSSIO PERSPECTIVE 4 N S Objective ☛ Iron (Fe) - Important concentration (3.91 wt.%) in urban sediments - key role in natural environments ( redox- active elements ) biogeochemical cycling trace contaminants toxicity ☛ Few studies were dedicated to multi element studies coupling major and trace mineral and reactivity bioavailability characterization Study the speciation and the potential mobilization of Fe and other heavy metals in urban stormwater sediments accumulated at the surface of an infjltration basin
RESUL TS PRESENTAT PRESENTAT MATERIAL MATERIAL RESUL TS CONCLUSION PERSPEC AND AND TIVE ION OF ION OF AND AND AND SUBJECT SUBJECT METHODS METHODS DISCUSSIO PERSPECTIVE DISCUSSIO 5 N S N Site Location of the 3 areas sampled in the Django Reinhardt infjltration basin Samples: 3 – 5 kg collected and homogenized Passed through a 4-mm Catchment in Chassieu, Lyon, sieve France
RESUL TS PRESENTAT MATERIAL CONCLUSION AND AND ION OF AND SUBJECT METHODS DISCUSSIO PERSPECTIVE 6 N S Methods Physico-chemical characterization Particle size distribution (PSD) pH Water content Organic matter Chemical composition – ICP-AES Mineralogical characterization X-ray difgraction Optical microscopy and scanning electron microscopy The Fourier transform infrared spectroscopy (FTIR) Sequential chemical extraction
RESUL TS PRESENTAT MATERIAL CONCLUSION AND AND ION OF AND SUBJECT METHODS DISCUSSIO PERSPECTIVE 7 Physico-chemical N S characterization Characteri Saturated Dry zone Wet zone stic zone T exture: T exture: T exture: Loam Silt loam Silt loam D10: 6.64 D10: 3.11 D10: 3.33 Granulome µm µm µm D50: 59.93 D50: 22.32 D50: 20.38 try µm µm µm D90: D90: D90: 506.85 µm 187.39 µm 125.46 µm ☛ Silts -- easily transported pH 7.0 7.0 7.0 as suspended particles in Water water content 20.9±0.8 52.6±4.6 66.5±0.6 ⇒ silts deposits (wt.%) • biofjlm development Organic and clogging • preferential matter 17.5 26.8 22.2 association with OM (wt.%)
RESUL TS PRESENTAT MATERIAL CONCLUSION AND AND ION OF AND SUBJECT METHODS DISCUSSIO PERSPECTIVE 7 Physicochemical N S characterization Trace metals content in sediments (ppm) Major elements content in sediments (wt.%) 25 2500 20 2000 15 1500 10 1000 5 500 0 0 Zn Cu Cr Pb Ni Si Ca Al Fe P S Dry zone Wet zone Dry zone Wet zone Saturated zone Saturated zone Thresholds (NOR: DEVO0650505A) ☛ similar total element contents
PRESENTAT MATERIAL RESUL TS CONCLUSION AND ION OF AND AND SUBJECT METHODS PERSPECTIVE DISCUSSIO 8 Physico-chemical S N NOR: DEVO0650505A - Decree of 9 characterization August 2006 concerning the levels to be taken into account for valorization of basin sediment in Trace metals content in sediments (ppm) Major elements content in sediments (wt.%) France 25 2500 20 2000 15 1500 10 1000 5 500 0 0 Zn Cu Cr Pb Ni Si Ca Al Fe P S Dry zone Wet zone Dry zone Wet zone Saturated zone Saturated zone Thresholds (NOR: DEVO0650505A) ☛ similar total element ☛ potential source of pollution ⇒ contents valorization
RESUL TS PRESENTAT MATERIAL CONCLUSION AND AND ION OF AND SUBJECT METHODS DISCUSSIO PERSPECTIVE 9 N S Mineralogical ☛ similar mineral characterization phases Mineral phase’s characterization and contents (wt.%) 35 ☛ calcite contents ↗️ ⇒ calcareous 30 subsoil 25 characteristic 20 15 10 5 0 Quartz Illite Plagioclase Hornblende Rutile Dry zone Wet zone Saturated zone
RESUL TS PRESENTAT MATERIAL CONCLUSION AND AND ION OF AND SUBJECT METHODS DISCUSSIO PERSPECTIVE 9 N S Mineralogical ☛ similar mineral characterization phases Mineral phase’s characterization and contents (wt.%) 35 ☛ calcite contents ↗️ ⇒ calcareous 30 subsoil 25 characteristic 20 ☛ calcite in wet 15 zone ↘️ ⇒ 10 dissolution with the circulation of water 5 0 Quartz Illite Plagioclase Hornblende Rutile Dry zone Wet zone Saturated zone
RESUL TS PRESENTAT MATERIAL CONCLUSION AND AND ION OF AND SUBJECT METHODS DISCUSSIO PERSPECTIVE 9 N S Mineralogical ☛ similar mineral characterization phases Mineral phase’s characterization and contents (wt.%) 35 ☛ calcite contents ↗️ ⇒ calcareous 30 subsoil 25 characteristic 20 ☛ calcite in wet 15 zone ↘️ ⇒ 10 dissolution with the circulation of water 5 0 ☛ chlorite and illite Quartz Illite Plagioclase Hornblende Rutile in dry zone ↘️ ⇒ seasonal change of stormwater Dry zone Wet zone Saturated zone ⇒ draining of
RESUL TS PRESENTAT MATERIAL CONCLUSION AND AND ION OF AND 1 SUBJECT METHODS DISCUSSIO PERSPECTIVE 0 N S ☛ very close Mineralogical composition of characterization three samples a b ☛ 3400 cm −1 -- 3620 cm −1 → O-H ⇒ clay minerals ☛ 1645 cm −1 → C=C T ypical FT-IR spectra of sediment: ⇒ aromatic cycles dry zone (a), wet zone (b), SEM microscopy images (a) saturated zone (c) and (b) showing minerals pyrite and framboid pyrite in the wet zone ☛ Occurrence of micrometric pyrite
RESUL TS PRESENTAT MATERIAL CONCLUSION AND AND ION OF AND 1 SUBJECT METHODS DISCUSSIO PERSPECTIVE 1 N S Sequential chemical extraction Sequential extraction procedure adapted from Clafg et al. (2010)
RESUL TS PRESENTAT MATERIAL CONCLUSION AND AND ION OF AND 1 SUBJECT METHODS DISCUSSIO PERSPECTIVE 2 N S Sequential chemical extraction ☛ exchangeable Fe ↘️ ☛ acido-soluble Fe ↗️ ⇒ carbonates and poorly ordered sulfjdes and oxides ☛ organic-Fe ↘️ ☛crystalline Fe oxide ↗️ ⇒ periodic freshwater fmooding and redox cycling Fe content in the sequential extraction ☛Pyrite-Fe ↘️ phases adapted with the Clafg et al. (2010) method
RESUL TS PRESENTAT MATERIAL CONCLUSION AND AND ION OF AND 1 SUBJECT METHODS DISCUSSIO PERSPECTIVE 3 N S CONCLUSION: This study: highlights the signifjcant amount of Fe (up to 3.91 wt.%) found in the sediment of urban stormwater infjltration basin and pyrite (reactive material compound) provides a basis for the rational interpretation of iron partitioning in the urban sediment Supports the management of maintenance dredging of the sediment (economize $) PERSPECTIVES: Future work : Particle settling velocity Isotopes of Fe Investigation of other basins Generalization and valorization
Thanks for your attention qiufang.zhan@insa- lyon.fr
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