典型草本植物对Cd-Zn-Cu污染河道底泥的修复

Remediation of Cd-Zn-Cu contaminated river sediment by typical herbaceous plants

以上海市某典型黑臭城市河道底泥为研究对象,利用6种典型草本植物对Cd-Zn-Cu复合污染河道底泥进行了修复实验研究,并考察了白三叶、高羊茅、黑麦草、披碱草、籽粒苋以及紫花苜蓿对底泥中重金属的耐受性、富集转运特征和修复效果.结果表明:除白三叶外,其余5种实验植物对底泥中的重金属均有良好的耐受性;黑麦草对Cd和Zn的吸收能力较强,其体内Zn含量高达707.69 mg/kg;披碱草对Cu的吸收能力较强;除紫花苜蓿对Zn的积累外,其余5种实验植物对重金属的积累主要在地下部分;高羊茅和黑麦草对Cd与Zn的富集系数均大于1,且对Cd、Zn及Cu的提取效率分别在7%、6%及2%以上,说明这2种实验植物对Cd-Zn-Cu复合污染河道底泥具有较大的修复潜力.

A typical black-odor urban river sediment in Shanghai was assessed in the study.Six characteristic herbaceous plants,namely Trifolium repens L.,Festuca arundinacea,Lolium perenne L.,Elymus dahuricus Turcz.,Amaranthus hypochondriacus L.,and Medicago sativa L.,were used as experimental plants in the phytoremediation of Cd-ZnCu contaminated river sediment.The tolerance to heavy metals,enrichment and transport features,and remediation efficiencies of the six plants in the river sediment were explored.The results showed that,except for Trifolium repens L.,the plants had good tolerance to heavy metals in the sediment.For Cd and Zn,the accumulation ability of Lolium perenne L.was higher,and the content of Zn in the plant was 707.69 mg/kg.The accumulation ability of Elymus dahuricus Turcz.to Cu was relatively higher.The accumulation of heavy metals in the plants was primarily within the roots,except for the accumulation of Zn in Medicago sativa L.The bioaccumulation factor of Cd and Zn in Festuca arundinacea and Lolium perenne L.was greater than 1.Furthermore,the Cd,Zn and Cu extraction efficiencies of Festuca arundinacea and Lolium perenne L.exceeded 7%,6%and 2%,respectively,which suggested stronger phytoextraction potentiality of the Cd-Zn-Cu contaminated river sediment.