AbstractCadmium (Cd) is known to be toxic to plants and animals and can be transported to groundwater and surface waters through specific physical mechanisms. The chemical dynamics of cadmium and other similar (heavy) metals in the soil environment is controlled by its interactions with solid and aqueous phases of soil. The concentration of cadmium and other metals in soil solution is strongly influenced and regulated by processes such as adsorption-desorption, ion exchange, precipitation-dissolution, and soil and solution phase composition. These processes, in turn, are a function of soil properties such as pH, density and charge distribution, thickness of the diffuse double layer and activity of the Cd present in solution. This report is intended to provide a comprehensive and critical review of the effects of these properties on cadmium transport.1. IntroductionHistorically the discovery of Cadmium (Cd) dates back to the 18th century (1817) by the petty German Friedrich Stromeyer who found it as an impurity in zinc carbonate. In the modern world, cadmium is used in many industrial, urban and agricultural applications ([1], [2]) and is often found together in sites contaminated with heavy metals. Since cadmium is a metal that is toxic to both humans [3] and animals, contamination of the environment and soil by cadmium has become a matter of great concern in recent decades. Therefore, it is important for chemists, environmental scientists, and engineers to understand the chemistry of cadmium interactions in soil to understand its bioavailability. Millions of tons of hazardous waste containing cadmium are generated worldwide on an annual basis. Due to inefficient waste management techniques and the loss of hazardous waste in the past, thousands of sites, e.g.... middle of paper ...... in terms of two fundamental mechanisms: specific adsorption, which is characterized by more selective and less reversible reactions, including chemisorbed inner sphere complexes, and nonspecific adsorption (or ion exchange), involving rather weak and less selective outer sphere complexes [14]. It is established that specific adsorption determines a strong and irreversible bond of heavy metal ions with organic matter and variable charged minerals while non-specific adsorption is an electrostatic phenomenon in which pore water cations are exchanged with cations close to the surface. Cation exchange is a type of outer sphere complexation with only a weak covalent bond between metals and charged ground surfaces. The process is naturally reversible and occurs rather quickly as is typical of controlled diffusion and electrostatic reactions [14].