Screening of chelating ligands to enhance mercury accumulation from historically mercury-contaminated soils for phytoextraction.
Screening of chelating ligands to enhance mercury accumulation from historically mercury-contaminated soils for phytoextraction.
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DOI：
10.1016/j.jenvman.2016.05.031
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发表时间：
2017-01
影响因子：
8.7
通讯作者：
Jianxu Wang;J. Xia;Xinbin Feng
中科院分区：
文献类型：
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作者：
Jianxu Wang;J. Xia;Xinbin Feng
筛选最佳的螯合配体，不仅具有高的能力，以提高植物从土壤中吸收汞（Hg），但也可以降低土壤中的生物可利用的汞浓度是必要的，以建立一个可行的化学辅助植物提取。因此，将芥菜暴露于历史上汞污染的土壤（总汞，90 mg kg−1），以研究七种螯合剂[硫代硫酸铵、硫代硫酸钠、硫酸铵、氯化铵、硝酸钠、乙二胺四乙酸（EDTA）和亚硫酸钠]在增强汞植物提取方面的效率;还研究了这些螯合剂导致的生物可利用汞的沥滤。对照（用双蒸水处理）植物组织中的汞浓度低于1 mg kg−1。在接受硫代硫酸铵和亚硫酸钠处理的植物中发现了显着较高的汞浓度。硫代硫酸铵和亚硫酸钠处理的生物积累因子和转运因子显著高于其他处理。硫代硫酸铵和亚硫酸钠处理后，植物对汞的吸收效率更高，这可能是由于形成了特殊的汞-硫代硫酸盐复合物，这种复合物可以优先被根部吸收并在植物组织中运输。与初始土壤和对照土壤相比，施用亚硫酸盐显著增加了土壤中生物有效态汞的含量，而硫代硫酸铵显著降低了生物有效态汞的含量。硫代硫酸铵处理土壤中生物有效态汞含量明显低于亚硫酸钠处理土壤，这可能是由于硫代硫酸盐与汞之间形成了不稳定的汞-硫代硫酸盐络合物，它们可以在土壤中反应产生较少的生物有效态汞。这项研究的结果表明，硫代硫酸铵可能是一个最佳的螯合配体植物提取由于其巨大的潜力，以提高汞在植物中的积累，同时降低土壤中的生物可利用的汞浓度。
Screening of optimal chelating ligands which not only have high capacities to enhance plant uptake of mercury (Hg) from soil but also can decrease bioavailable Hg concentration in soil is necessary to establish a viable chemically-assisted phytoextraction. Therefore,Brassica junceawas exposed to historically Hg-contaminated soil (total Hg, 90 mg kg−1) to investigate the efficiency of seven chelating agents [ammonium thiosulphate, sodium thiosulphate, ammonium sulfate, ammonium chloride, sodium nitrate, ethylenediaminetetraacetic acid (EDTA), and sodium sulfite] at enhancing Hg phytoextraction; the leaching of bioavailable Hg caused by these chelating agents was also investigated. The Hg concentration in control (treated with double-distilled water) plant tissues was below 1 mg kg−1. The remarkably higher Hg concentration was found in plants receiving ammonium thiosulphate and sodium sulfite treatments. The bioaccumulation factors and translocation factors of ammonium thiosulphate and sodium sulfite treatments were significantly higher than those of the other treatments. The more efficient uptake of Hg by plants upon treatment with ammonium thiosulphate and sodium sulfite compared to the other treatments might be explained by the formation of special Hg-thiosulphate complexes that could be preferentially taken up by the roots and transported in plant tissues. The application of sulfite significantly increased bioavailable Hg concentration in soil compared with that in initial soil and control soil, whereas ammonium thiosulphate significantly decreased bioavailable Hg concentration. The apparent decrease of bioavailable Hg in ammonium thiosulphate-treated soil compared with that in sodium sulfite-treated soil might be attributable to the unstable Hg-thiosulphate complexes formed between thiosulphate and Hg; they could react to produce less bioavailable Hg in the soil. The results of this study indicate that ammonium thiosulphate may be an optimal chelating ligand for phytoextraction due to its great potential to enhance Hg accumulation in plants while decreasing bioavailable Hg concentration in the soil.