In nature, when contaminants come in contact with geomaterials (i.e., soil, minerals and rock mass), geomaterial-contaminant interaction occurs, which can be quantified, mathematically, by employing distribution or partitioning coefficient, k_d. This interaction is strongly influenced by the geomaterial and contaminant specific parameters. Among these parameters, the concentration and nature of the contaminant (in solution form) is one of the most important parameters that control this interaction critically. However, it is the authors’ hypothesis that another parameter, electrical conductivity of the geomaterial-contaminant system (GCS), which is dependent on type of the geomaterial (i.e., its chemical and mineralogical properties) and contaminant(s) could be used for a precise understanding of geomaterial-contaminant interaction. Hence, in order to investigate the effect of the concentration and electrical conductivity of the GCS on this interaction, geomaterials and contaminants of different types were used in this study for performing a series of batch tests and electrical conductivity measurements under controlled environmental conditions. Based on these investigations, guidelines for selecting appropriate concentration of the contaminant(s), M_crt, to quantify geomaterial-contaminant interaction have been developed and recommended for the precise determination of k_d.