摘要
Fractions of various heavy metals in a sulfidic minespoil were investigated. Column leaching experimentwas also conducted to simulate 'acid mine drainage' (AMD) from the minespoil. The results show thatleaching of heavy metals from the minespoil was extremely significant during the initial water flushing.The amounts of heavy metals leached out dramatically reduced after leaching twice. It is worthwhile tonote that in this study, Zn, Mn, Fe, As and Ni in the first leachate exceeded the total amount of eachcorresponding water-extractable (1:5, soil:water) metal contained in the minespoil sample. This appears tosuggest that 1:5 water extraction did not allow accurate estimation of water-leachable concentrations of theabove heavy metals. This work has implications for the management of sulfidic minespoils. Acid drainageof great environmental concerns is likely to occur only during heavy rainfall events after substantial solubleand readily exchangeable acid and metals are accumulated in the minespoils. The slow-reacting fractionsother than water-soluble and readily exchangeable fractions may pose little environmental hazards. This isparticularly true for Pb, As and Ni.
Fractions of various heavy metals in a sulfidic minespoil were investigated.Column leaching experiment was also conducted to simulate 'acid mine drainage' (AMD) from theminespoil. The results show that leaching of heavy metals from the minespoil was extremelysignificant during the initial water flushing. The amounts of heavy metals leached out dramaticallyreduced after leaching twice. It is worthwhile to note that in this study, Zn, Mn, Fe, As and Ni inthe first leachate exceeded the total amount of each corresponding water-extractable (1:5,soil:water) metal contained in the minespoil sample. This appears to suggest that 1:5 waterextraction did not allow accurate estimation of water-leachable concentrations of the above heavymetals. This work has implications for the management of sulfidic minespoils. Acid drainage of greatenvironmental concerns is likely to occur only during heavy rainfall events after substantialsoluble and readily exchangeable acid and metals are accumulated in the minespoils. Theslow-reacting fractions other than water-soluble and readily exchangeable fractions may pose littleenvironmental hazards. This is particularly true for Pb, As and Ni.
基金
Project partly supported by an internal grant of Southern Cross University,Australia(Project No.305093).
