Spatial distribution and molecular speciation of copper in indigenous plants from contaminated mine sites: Implication for phytostabilization

JOURNAL OF HAZARDOUS MATERIALS

卷:381

Article

Cui, Jin-li^1,2  Zhao, Yan-ping¹  Chan, Ting-shan³  Zhang, Li-li⁴  Tsang, Daniel C. W.¹  Li, Xiang-dong¹ 

[1] Hong Kong Polytech Univ, Dept Civil & Environm Engn, Hung Hom, Kowloon, Hong Kong, Peoples R China

[2] Guangzhou Univ, Key Lab Water Qual & Conservat Pearl River Delta, Minist Educ, Sch Environm Sci & Engn, Guangzhou, Guangdong, Peoples R China

[3] Natl Synchrotron Radiat Res Ctr, 101 Hsin Ann Rd,Hsinchu Sci Pk, Hsinchu 30076, Taiwan

[4] Chinese Acad Sci, Shanghai Synchrotron Radiat Facil, Shanghai Adv Res Inst, Shanghai 201214, Peoples R China

关键词: Contaminated sites;    Metal uptake;    Phytostabilization;    Synchrotron-based X-ray techniques;    Rhizosphere;    Copper;   

DOI  :  10.1016/j.jhazmat.2019.121208

来源: Elsevier

【 摘 要 】

Contaminated mining sites require ecological restoration work, of which phytoremediation using appropriate plant species is an attractive option. Our present study is focused on one typical contaminated mine site with indigenous plant cover. The X-ray absorption near edge structure (XANES) analysis indicated that Cu (the major contaminant) was primarily associated with goethite (adsorbed fraction), with a small amount of Cu oxalate-like species (organic fraction) in mine affected soil. With growth of plant species like Miscanthus floridulus and Stenoloma chusanum, the Cu-oxalate like organic species in rhizosphere soil significantly increased, with corresponding decrease in Cu-goethite. In the root cross-section of Miscanthus floridulus, synchrotron-based micro-X-ray fluorescence (mu-XRF) microscopy and micro-XANES results indicated that most Cu was sequestered around the root surface/epidermis, primarily forming Cu alginate-like species as a Cu-tolerance mechanism. From the root epidermis to the cortex and vascular bundle, more Cu(I)-glutathione was observed, suggesting reductive detoxification ability of Cu(II) to Cu(I) during the transport of Cu in the root. The observation of Cu-histidine in root internal cell layers showed another Cu detoxification pathway based on coordinating amino ligands. Miscanthus floridulus showed ability to accumulate phosphorous and nitrogen nutrients in rhizosphere and may be an option for in situ phytostabilization of metals in contaminated mining area.

【 授权许可】

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