Fractionation characterizations and environmental implications of heavy metal in soil from coal mine in Huainan, China

The toxicity and availability of heavy metals in soil are determined by modes of occurrence of metals. Therefore, the quantification of associations of heavy metals is more significant than the assessment of their total concentrations. Thirty soil samples that were collected from coal mining areas with different mining durations in Huainan Coalfield were employed to determine the modes of occurrence and potential environmental implications of heavy metals. Sequential chemical extraction procedure was carried out to determine the fractionation profiles of heavy metals. The elevated concentrations of heavy metals in the mining activities areas indicated that the mining activities (mining, transportation, utilization and waste disposal) might be one of the sources for the heavy metal pollution in soil. The fractionation characterizations are various among different heavy metals. According to the international sediment quality guidelines (SQGs) calculations, the adverse biological effects caused by Cd, Cr, Pb and Zn are expected to be negligible. For As and Cu, the occasional adverse biological effects are predicted. The risk assessment code reveals that these heavy metals could pose a medium risk to the ecosystem. Consequently, environmental issues involved in heavy metals in the studied coal mining area soil deserve urgent concern.