Heavy metal leaching from mine tailings as affected by plants

D. Zhu, A. P. Schwab, Margaret Katherine Banks

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

A column experiment was conducted to determine the impact of soil cover and plants on heavy metal leaching from mine tailings and heavy metal contaminated soil. Columns made of PVC were constructed with 30 cm subsoil covered by 30 cm of mine tailings followed by 0, 30, or 60 cm of clean topsoil. Two grasses, tall fescue (Festuca arundinacea Schreb.) and big bluestem (Andropogon gerardii), were grown in the columns. The columns were leached at a slow rate for 1 yr with a 0.001 M CaCl2 solution under unsaturated conditions. The presence of both tall fescue and big bluestem increased Zn and Cd concentrations in the leachate. Lead concentrations in leachates were not affected by the presence of plants. Although plants generally reduced the total amount of water leached, total mass of Zn and Cd leached generally was not impacted by plants. Total mass of Pb leached was positively correlated (r = 0.9) with total leachate collected from each column. Covering the mine tailings with 60 cm of topsoil (with or without vegetation) increased the mass of Zn and Cd leached relative to no topsoil. When the subsoil was absent, Zn and Cd leaching increased by as much as 20- fold, verifying the ability of soil to act as a sink for metals. Mine tailing remediation by establishing vegetation can reduce Pb movement but may enhance short-term Cd and Zn leaching. However, the changes were relatively small and do not outweigh the benefits of using vegetation in mine tailings reclamation.

Original languageEnglish (US)
Pages (from-to)1727-1732
Number of pages6
JournalJournal of Environmental Quality
Volume28
Issue number6
DOIs
StatePublished - Jan 1 1999

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Management, Monitoring, Policy and Law

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