AbstractSorption of halogenated single carbon organic contaminants onto a sandy loam has been found to be controlled by the electrostatic attraction between a slightly negatively (δ−) charged clay particle and a positively (δ+) charged carbon atom within the solvent molecule. Adsorption isotherms for chloroform, bromodichloromethane and methylene chloride indicate that the extent of sorption appears to have a direct functional relationship to the molecular charge distribution within the solvent molecule, and to the atomic radii of the molecular substituents of the contaminant. When a carbon atom is saturated with highly electronegative substituents (e.g. carbon tetrachloride), an electron cloud surrounds the molecule and shields the slightly positive (δ+) carbon nuclei. This shielding effect limits the sorption that occurs. A study on carbon tetrachloride sorption resulted in no detectable sorption onto the sandy loam soil. This theory of adsorption is defined as Electrophysical Sorption (EPS) because it reflects the combination of electrostatic and physical contributions to sorp