Effect of Thioligands on Plant-Hg Accumulation and Volatilisation from Mercury-contaminated Mine Tailings

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• 作者：Fabio N. Moreno ; Christopher W. N. Anderson ; Robert B. Stewart ; Brett H. Robinson ; Roberto Nomura ; Mory Ghomshei and John A Meech
• 关键词：mercury ; mine tailings ; phytoextraction ; plant ; Hg accumulation ; thioligands ; volatilisation
• 刊名：Plant and Soil
• 出版年：2005
• 出版时间：August 2005
• 年：2005
• 卷：275
• 期：1-2
• 页码：233-246
• 全文大小：386 KB

文摘

This study investigated the effect of thioligands on mercury (Hg) volatilisation and plant accumulation for Brassica junceaplants grown in mine tailings collected from artisanal gold mines in Brazil (the Serra Pelada mine) and China (the Gold Mountain mine). Plants were treated with either (NH₄)₂S₂O₃or NH₄SCN and enclosed in gas-tight volatilisation chambers. Elemental Hg released from substrates was captured in a two-trap system containing 5 KMnO₄dissolved in 2N H₂SO₄. Mercury accumulation was enhanced in the presence of (NH₄)₂S₂O₃ for plants grown in GM tailings. There was no significant increase in the plant-Hg accumulation after application of NH₄SCN to the SP tailings. Volatilisation from planted substrates was not affected by the application of thioligands to either GM or SP mine tailings. Mercury volatilisation from planted substrates was significantly higher than from control substrates. Abiotic (photoreduction) and biotic (microbial interactions) factors might be linked to the enhanced plant effect on Hg volatilisation. There was no significant correlation for the Hg mass released from substrates and the amount of Hg uptake by roots and translocated to shoots. Our results indicate that volatilisation and plant-Hg accumulation are two independent processes. Thiosulphate-induced plant-Hg accumulation may be a potential tool for the phytoextraction of Hg contaminated soils but there are risks of groundwater contamination by Hg-containing leachates.