Assessment of heavy metals leachability characteristics and associated risk in typical acid mine drainage (AMD)-contaminated river sediments from North China.

Acid mine drainage (AMD) is a worldwide environmental problem, characterized by low pH values and high concentrations of heavy metals. Heavy metal pollution of sediments caused by AMD has attracted widespread attention. However, research works on the leachability and distribution characteristics along with the ecological and health risks assessment of AMD-polluted sediment are limited. 15 sediments samples were collected from an AMD-polluted river, Shandi River, North China to analyze the leachability concentration, potential sources, and associated risk of eight metals, namely Ni, Cd, Cu, Zn, Fe2+, Fe3+, Pb, and Mn. Our results showed that Mn, Ni, Fe3+, and Fe2+ were the main leachate pollutants in the Shandi river. Certain levels of ecological risks existed in AMD-polluted stations and Ni was the common key metal that caused the high ecological risk factor in S1, S2, and S4. Cu, Ni, and Zn were the three metals that caused high or moderate risk to zebrafish. Mn and Fe were the main heavy metals that caused non-carcinogenic risks both for adults and children and Ni was another main heavy metal that caused non-carcinogenic risks for children. Ni and Cd can induce carcinogenic risks in these areas. Pearson's correlation and PCA results supported that these metals possibly originate from common AMD–polluted sources. The technology of "gravitational settling-neutralizing filter-aeration-coagulation-filtration" (GSNFACF) was an effective strategy to amend AMD and could be used for future cleaner production and environmental sustainability. These results suggested that the main contaminants in the sediments of the Shandi River should be preferentially treated by the government. [ABSTRACT FROM AUTHOR]