Column Experiment Results on Metal Ion Migration at the Xiangtan Manganese Mine Wasteland in Central South China

Abstract- Column experiment simulations were carried out to determine potential metal ion migration in order to establish the environmental impact of a manganese mine wasteland and to understand the transport dynamics of heavy metal migration by way of two different soil types (tailings and tailings mud) within the Xiangtan Manganese Mine wasteland. Simulations were conducted at the Research Section of Forest Ecology, CSUFT. Results show a lower water infiltration rate for tailings mud compared to tailings. Considerably higher water content was found in tailings mud, and leachate from tailings mud contained considerably higher metal ion concentrations. Mg, Mn, Ca, K, Zn, Ni, Pb, Fe, Cu, and Cd is the order of metallic ion concentrations from high to low found in the leachate of tailings. However, this order altered slightly during instances when a lower Mn concentration (compared to Ca) was found. Almost all tailings mud metal ion concentrations in the leachate were higher compared to tailings, especially in the case of Mn, which was higher by a factor of 25. K concentrations were also higher by a factor of 10. The primary metallic ions found in the leachate for both tailings mud and tailings were Mg, Mn, Ca, and K. Almost all metal ion concentrations for both leachates decreased sharply with an increase in the number of leaching events. Mg, Mn, Ca, and K concentrations were the highest during the first leaching event and decreased sharply during the following two leaching events. However, Ni, Pb, Fe, Cu, and Cd concentrations remained almost constant at very low concentrations, especially for the tailings leachate. These results, together with a detailed field investigation of prevailing conditions, would be useful for mine wasteland phytoremediation initiatives, and contribute to the development of ecological restoration.