EDTA, citric acid, and DOM solutions served as washing reagents in the investigation. Both single chelating washing and chelate-DOM washing were performed in order to compare the remediation of the topsoil. However, the use of a chelating agent was unnecessary for subsoil washing due to the low Cu concentration in the subsoil. The final fertility for each treatment was measured to compare with the original fertility and for discussion. It is important to note that the samples that were washed with all washing reagents were rinsed using 95% ethanol to clear surplus ions and materials suspended in soil voids prior to fertility determination. All the experiments were performed in duplicate.