Identification of contaminated soils by dielectric constant and electrical conductivity

To develop effective decontamination methods, characterization and identification of contaminated soils are needed. However, current methods of environmental soil characterization involve either soil sampling and analysis for targeted species in the laboratory or soil electrical conductivity measurements. Soil sampling and analyzing in the laboratory involves the risk of sample contamination during handling and testing. Furthermore, it is destructive. To overcome deficiencies of current identification and characterization methods, the use of dielectric constant and electrical conductivity of the soil-fluid system has been suggested. However, little is known about the dielectric behavior of a contaminated soil-fluid system. Thus, the objective of this study is to investigate the possibility of using dielectric constant and electrical conductivity to characterize and identify contaminated fine-grained soils. To investigate the usefulness of the preceding concept, the dielectric constant and electrical conductivity of kaolinite, bentonite, and a local soil are determined at various ion concentrations, organic liquids, and moisture content. Results show that both dielectric constant and electrical conductivity of soil-fluid system are mainly controlled by those of pore fluid.