Remediation of metal ore mine waste using combined chemical- and phytostabilisation

Abstract

The combination of chemical stabilisation (using fly ash, lime and steel shots) and phytostabilisation (using grass mixture and two Sorghum species ) were applied to remediate a highly acidic metal ore mine waste in Gyöngyösoroszi, Hungary. The change in metal mobility was monitored by chemical, biological and ecotoxicological methods. Chemical stabilisation reduced the amount of Cd from 441 to 0.42 μ g l^-1, Cu from 1510 to 11.7 μ g l^-1 and Zn from 89079 to 48.8 μ g l^-1 in drainage water and extractable As from 0.404 to 0.086 mg kg^-1 in waste within two years. The high toxicity of the mine waste was reduced to non-toxic and healthy vegetation developed on the previously barren surface with metal content fulfilling animal fodder quality criteria. The technology reduced the risk on all possible pathways fulfilling all target criteria.