Evaluation of different amendments to stabilize antimony in mining polluted soils

Soil pollution with antimony is of increasing environmental concern worldwide. Measures for its control and to attenuate the risks posed to the ecosystem are required. In this study the application of several iron and aluminium oxides and oxyhydroxides as soil amendments was evaluated in order to assess their feasibility to stabilize Sb in mining polluted soils. Mine soils with different pollution levels were amended with either goethite, ferrihydrite or amorphous Al oxide at various ratios (0–10%). The effectiveness of such treatments was assessed by both batch and column leaching tests. The use of ferrihydrite or amorphous Al oxide proved to be highly effective to stabilize Sb. Immobilization levels of 100% were found when doses of 5% ferrihydrite or 10% amorphous Al oxide were applied, regardless of the soil Sb load. Column leaching studies also showed a high Sb leaching reduction (>75%) when soils were amended with 1% ferrihydrite or 5% amorphous Al oxide. Moreover, such treatments proved to simultaneously immobilize As and Pb in a great extent when soils were also polluted with such toxic elements.