Evaluation of Metal Mobility in Waste Rock Soils Using Sequential Extraction at the Haizhou Coal Mine, China

AbstractThe pollution and metal mobility in a large coal waste rock pile were assessed through BCR sequential extraction method. The metal fractions were determined using a sequential extraction procedure (BCR method) in the waste rock soils in order to assess potentially mobile amounts of heavy metals in waste rock pile. The results for metals Cd, Cr, Cu, Ni, Pb and Zn demonstrated that residual fractions account for the largest proportion of the total metals particularly for Cr, Ni and Zn which indicates these metals are from natural origin and they are not easily mobilized under the natural conditions. Risk assessment code (RAC) analysis indicated that although the metals presented a low overall risk to the aquatic environment, cadmium showed a moderate risk to the ecosystem.