Complex resistivity characteristics of saltwater-intruded sand contaminated by heavy metal

Abstract

Different pollutants affect electrical characteristics of soil, e.g., electric resistivity and capacity. The most extensively used non-intrusive methods in mapping these physical characteristics are electrical method. To better understand the effect of different hydrogeological and environmental process on resistivity and phase of complex resistivity under water-saturated soil, we carried out a controlled laboratory experiment where the host material was simulated by sand soil and the hydrogeological and environmental processes by groundwater table rise, seawater intrusion and heavy metal contamination. The experiment measured the resistivity and phase of soil saturated and unsaturated, with different pollutants added, together with their time-lapse change in a well-controlled column. With the involvement of more measurement parameters, complex resistivity method can provide more information than resistivity method, thereby having better performance in the detection and monitoring of changes in electrical properties of complex contaminated sites. For example, it is capable of discriminating the different contamination process, in this case, e.g., seawater intrusion and heavy metal contamination. In addition, it is still sensitive to the change of pollutant concentration even in site with high added concentration. Furthermore, simulating the saltwater-intruded site contaminated by manganese, it was found that the change of resistivity (ρ) can hardly be observed, while the responses of phase (φ) are so obvious that can be clearly observed.

A multiscale accuracy assessment of moisture content predictions using time-lapse electrical resistivity tomography in mine tailings

“…For instance, the lower pore water EC reported for the field cover must be considered in order to avoid underestimation of VWC in the field. Here again, the pore water EC correction is particularly important in the context of mining wastes, given (i) the strong pore water EC contrasts that are generally observed between clean water and water in contact with tailings and waste rocks, whether or not affected by contaminated drainage and (ii) the strong temporal variations of pore water EC in mining wastes (e.g., 45 , 139 , 140 ).…”

A resistivity-based experimental compaction model for Yunnan laterite

“…On this basis, some models have been established that consider different influence factors in different situations for various soil types. Resistivity models for unsaturated sands were developed for different degrees of contamination 8,19 , and the resistivity model for unsaturated clay, as well as a prediction model for heavy-metal contaminated clay, have been established 9,20 . Subsequently, some scholars have proposed unsaturated loess resistivity models with different water and NaCl contents as variables 21,22 , along with the resistivity models of unsaturated and saturated expansive soils 15,23 .…”