烟草—红叶甜菜轮作对镉污染农田的修复潜力试验

Phytoextraction of cadmium contaminated agricultural soil by tobacco and swiss chard rotation systems

  • 摘要: 植物修复重金属污染土壤具有环境友好、成本适中、可原位修复等优势。采集中、高重金属污染风险的农田土壤开展盆栽试验,探究烟草—红叶甜菜轮作模式对2种农田污染土壤中Pb、Zn、Cu、Cd的修复潜力。结果表明:烟草和红叶甜菜对2种农田污染土壤中Pb、Zn、Cu、Cd均有一定的富集能力,其中对Cd的富集能力最为显著;在高重金属污染风险土壤中,烟草成熟期下部叶的Cd浓度最高,达41.63 mg/kg,富集系数(BCF)和转运系数(TF)分别为17.06和17.42,红叶甜菜成熟期根部Cd浓度为7.55 mg/kg,BCF为3.85,高于地上部位;在中重金属污染风险土壤中,烟草成熟期下部叶的Cd浓度达34.59 mg/kg,BCF和TF分别为40.69和13.67,红叶甜菜成熟期根部Cd浓度为4.33 mg/kg,BCF为7.69;轮作试验结束后,中、高重金属污染风险土壤中Pb、Zn、Cu、Cd全量浓度分别下降了2.99%、3.55%、12.41%、57.64%和3.32%、1.63%、9.45%、24.59%,同时,土壤中Pb、Cu、Cd有效态浓度显著降低。烟草—红叶甜菜轮作模式在中、高重金属污染风险农田土壤修复中具有一定的应用潜力。

     

    Abstract: Phytoremediation of heavy metal contaminated soil has the advantages of environmental friendliness, moderate cost and in situ restoration. The farmland soil with medium and high risk of heavy metal pollution were selected for pot experiments to explore the remediation potential of tobacco (Nicotiana tobaccum L.) and swiss chard (Beta vulgaris var. cicla L.) rotation model for the heavy metals Pb, Zn, Cu and Cd in the contaminated soil of two kinds of farmland. The results showed that, on the tested soils, tobacco and swiss chard had certain enrichment capacity for Pb, Zn, Cu and Cd, especially for Cd. In the soil with high heavy metal pollution risk, the concentration of Cd in the lower leaves of tobacco at the mature stage was the highest, which reached 41.63 mg/kg, and the enrichment coefficient and transport coefficient of Cd with lower leaves of tobacco was 17.06 and 17.42, respectively; the Cd concentration in the roots of swiss chard at the mature stage was 7.55 mg/kg, and the enrichment coefficient was 3.85, significantly higher than that in the above ground part. According to the pot experiment with soil of medium heavy metal pollution risk, the concentration of Cd in the lower leaves of tobacco at the mature stage reached 34.59 mg/kg, and the enrichment coefficient and the transport coefficient was 40.69 and 13.67, respectively; the Cd concentration in the roots of swiss chard at the mature stage was 4.33 mg/kg, and the enrichment coefficient was 7.69. After the tobacco-swiss chard rotation pot experiment, the total amount of Pb, Zn, Cu and Cd in the two kinds of soils decreased by 2.99%, 3.55%, 12.41%, 57.64%, and 3.32%, 1.63%, 9.45%, 24.59%, respectively. At the same time, the effective concentrations of heavy metals Pb, Cu and Cd in soils were significantly reduced. In conclusion, the tobacco-swiss chard rotation model could provide good application potential in remediation of farmland polluted by heavy metals with medium and high pollution risk.

     

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