Imaging Brilliant Blue Stained Soil by Means of Electrical Resistivity Tomography

Abstract

A: ERT, electrical resistivity tomography; RGB, red, green, blue; TDR, time domain refl ectometry.O R Temporal mapping of the three-dimensional spa al distribu on of solute transport in soils is needed for an improved understanding of the underlying processes. Numerous studies have confi rmed that Brilliant Blue imaging provides spaally highly resolved informa on on solute transport in soils. A drawback of the method, however, is its destruc ve character, which prevents three-dimensional mapping of the temporal evolu on of Brilliant Blue plumes or fronts. In this study, we determined that the nega ve ionic charge of the Brilliant Blue molecule for moderately acid and basic environments provides an electrical conduc vity contrast that can be detected by means of me domain refl ectometry (TDR) and electrical resis vity tomography (ERT). Time-lapse ERT supplies three-dimensional spa otemporally resolved image data through minimally invasive measurements but with limited spa al resolu on. A joint applica on of Brilliant Blue imaging and ( me-lapse) ERT off ers poten al benefi ts such as ERT image valida on by dye staining, spa otemporally resolved Brilliant Blue displacement studies, and improved ERT inversion regulariza on based on Brilliant Blue image-derived solute plume or front characteris cs. This study illustrates the eff orts needed to quan ta vely relate Brilliant Blue concentra on and electrical conduc vity as well as the poten al and limita ons of noninvasive smoothness-constrained ERT for solute imaging in soils.

Observing Solute Transport in the Capillary Fringe Using Image Analysis and Electrical Resistivity Tomography in Laboratory Experiments

“…The regularization parameter that weights this term is determined such that the data are fitted within noise, i.e., the smoothest of all equivalent models that fit the data is chosen. There have been numerous studies that discussed the resolution limitations of ERT in the hydrologic framework (e.g., Day‐Lewis et al, 2005; Koestel et al, 2009). The smoothness of the results depends on the experimental design, i.e., electrode positions and arrays, and the data errors.…”

Preferential Flow in a Pedological Perspective

“…Quantitative descriptors of pore networks and soil structure can be related to transport behavior if solute breakthrough experiments are carried out in the same columns used for imaging (e.g. Electrical resistance tomography (Olsen et al, 1999) can be used to obtain direct images of tracer transport (providing the water content and temperature are constant) at larger scales and thus is well suited to studies of Darcy-scale heterogeneous flow (Koestel et al, 2009). Electrical resistance tomography (Olsen et al, 1999) can be used to obtain direct images of tracer transport (providing the water content and temperature are constant) at larger scales and thus is well suited to studies of Darcy-scale heterogeneous flow (Koestel et al, 2009).…”

Three‐Dimensional Time‐Lapse Geoelectrical Monitoring of Water Infiltration in an Experimental Mine Waste Rock Pile

“…Various applications of the ERT method have been presented over the past two decades for: hydrogeological studies (Clément et al, 2014; Hübner et al, 2017, 2015; Nimmer et al, 2008), agricultural applications (Cassiani et al, 2012; Michot et al, 2003; Uhlemann et al, 2016b), ground water resources (Binley et al, 2002; Kuras et al, 2009), tracer and contaminant plume monitoring (Audebert et al, 2016a, 2016b; Koestel et al, 2009, 2008; Kuras et al, 2016, 2014; Power et al, 2014; Rucker et al, 2011; Wilkinson et al, 2010), geotechnical applications (Chambers et al, 2014, 2015; Uhlemann et al, 2016a, 2017) and mining environmental issues (Anterrieu et al, 2010; Dimech, 2018; Dimech et al, 2018, 2017; Intissar, 2009; Power et al, 2018).…”