title: Monitoring the injection of microscale zerovalent iron particles for groundwater remediation by means of complex electrical conductivity imaging.
abstract: The injection of microscale zerovalent iron (mZVI) particles for groundwater remediation has received much interest in recent years. However, to date, monitoring of mZVI particle injection is based on chemical analysis of groundwater and soil samples and thus might be limited in its spatiotemporal resolution. To overcome this deficiency, in this study, we investigate the application of complex electrical conductivity imaging, a geophysical method, to monitor the high-pressure injection of mZVI in a field-scale application. The resulting electrical images revealed an increase in the induced electrical polarization (∼20%), upon delivery of ZVI into the targeted area, due to the accumulation of metallic surfaces at which the polarization takes place. Furthermore, larger changes (>50%) occurred in shallow sediments, a few meters away from the injection, suggesting the migration of particles through preferential flowpaths. Correlation of the electrical response and geochemical data, in particular the analysis of recovered cores from drilling after the injection, confirmed the migration of particles (and stabilizing solution) to shallow areas through fractures formed during the injection. Hence, our results demonstrate the suitability of the complex conductivity imaging method to monitor the transport of mZVI during subsurface amendment in quasi real-time.
authors.affiliation: †Geophysics Research Group, Vienna University of Technology, Gusshausstraße 27-29, E120-3, 1040 Vienna, Austria.
authors.forename: Adrián
authors.initials: A
authors.lastname: Flores Orozco
authors.affiliation: ‡Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol, Belgium.|§Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors.forename: Milica
authors.initials: M
authors.lastname: Velimirovic
authors.affiliation: ⊥DIATI-Dipartimento di Ingegneria del Territorio, dell'Ambiente e delle Infrastrutture, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Tosco
authors.affiliation: ¶Department of Geophysics, Steinmann Institute, University of Bonn, Meckenheimer Allee 176, 53115 Bonn, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kemna
authors.affiliation: ∥SAPION, Oude Bevelsesteenweg 51, 2560 Nijlen, Belgium.
authors.forename: Hans
authors.initials: H
authors.lastname: Sapion
authors.affiliation: #VEGAS, University of Stuttgart, Pfaffenwaldring 61, 70569 Stuttgart, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Klaas
authors.affiliation: ⊥DIATI-Dipartimento di Ingegneria del Territorio, dell'Ambiente e delle Infrastrutture, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
authors.forename: Rajandrea
authors.initials: R
authors.lastname: Sethi
authors.affiliation: ‡Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol, Belgium.
authors.forename: Leen
authors.initials: L
authors.lastname: Bastiaens
mesh_terms: D001530:Belgium; D004553:Electric Conductivity; D052918:Environmental Restoration and Remediation; D060587:Groundwater / Q000737:chemistry*; D006843:Hydrocarbons, Chlorinated / Q000032:analysis; D021621:Imaging, Three-Dimensional; D007501:Iron / Q000737:chemistry*; D012996:Solutions
chemical_list: D006843:Hydrocarbons, Chlorinated; D012996:Solutions; D007501:Iron