Phytoremediation of Gold Mine Tailings Amended with Iron-Coated and Uncoated Rice Husk Ash by Vetiver Grass (Vetiveria zizanioides(Linn.) Nash)

F S Tariq,A Z Aris,A W Samsuri,D S Karam

doi:10.1155/2016/4151898

Abstract

This study was undertaken to determine the effects of rice husk ash (RHA) and iron-coated rice husk ash (Fe-RHA) on phytoavailability of As, Cd, Cr, Cu, Mn, Pb, and Zn to vetiver grass grown in gold mine tailings amended with either RHA or Fe-RHA at 0%, 5%, 10%, and 20% (w/w). The results showed that the RHA amended tailings recorded higher concentration of As in the shoot and the root and higher concentration of Cr and Mn in the root compared to the untreated tailings which was used as a control. The biological accumulation coefficient (BAC) and bioconcentration factor (BCF) values of the vetiver grass for As and Zn increased with RHA application rate but the biological transfer coefficient (BTC) values of As and Zn were decreased. In Fe-RHA amended samples, As concentration in the shoot and root concentrations of Cd and Zn were significantly higher compared to the control. The Fe-RHA treated samples had lower BAC and BTC values for As and Zn than the control. However, the BCF values for those elements were higher than the control. The concentration of Pb was not detected in any of the samples.

Highlights

Tailings are the components of the primary mineral-bearing rock left after the extraction of minerals like gold, copper, and silver [1]
A field study was conducted by Singh and Agrawal [9] to assess the suitability of sewage sludge amendment in soil for rice (Oryza sativa L.) by evaluating the heavy metal accumulation and growth of plants in soil amended with sewage sludge at either 0, 3, 4.5, 6, 9, or 12 kg m−2
The results revealed that both rice husk ash (RHA) and FeRHA application had no impact on the cation exchange capacity (CEC) of the mine tailings

Summary

Introduction

Tailings are the components of the primary mineral-bearing rock left after the extraction of minerals like gold, copper, and silver [1]. There are several methods of cleaning up the harmful effects of heavy metal on contaminated sites which include, among others, physical removal (excavation), in situ stabilization of these metals, and utilization of plants to extract the metals from the polluted site. Each of these approaches has its advantages and disadvantages and its success depends on the nature and size of the contaminated site. They found that sewage sludge amendment modified the physicochemical properties of soil, increasing the availability of heavy metals in soil and resulting in higher accumulation in plant parts

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Conclusion