Characterization of heavy metals in coal gangue-reclaimed soils from a coal mining area

Abstract Coal gangue is practically used as a filling material for soil reclamation in the coal mining subsidence areas. Due to the toxic elements enriched in coal gangue, the reclaimed soils potentially pose great environmental concerns. In this study, we investigated the distribution and mobility of six heavy metals (As, Cr, Cu, Mn, Pb and Zn) in coal gangue-reclaimed soils (n = 26) from a typical coal mining area of Huainan Coalfield, China. The concentrations of Cu, Pb and Zn in the reclaimed soils were enriched by a factor of 1.51, 1.48 and 2.05 compared to the original agricultural soils, indicating potential migration of these heavy metals from coal gangue to soils. The soils of the finest particle grain size fraction (