玉米对受污染河道复合沉积物的修复

Phytoremediation of Complex Contaminants in Sewage River Sediment by Maize

为减轻城市河道沉积物的受污染程度,利用温室盆栽玉米对其中的污染物进行了修复研究试验.结果表明,玉米体内累积最多的重金属是Zn,占沉积物中Zn总量的56.69%,其中地上部分为1 985.56 mg.kg-1,占沉积物中Zn总量的30.16%,其余重金属(Pb、Cu、Ni、Cd)均为地上部分小于地下部分;Cd在玉米地上部分的累积量为2.33 mg.kg-1,为沉积物中Cd总量的40.10%;地上部累积的Zn、Pb、Cu和Ni等重金属数量与其离子交换态量显著相关,与重金属总量相关性不明显.种植玉米后沉积物中大分子有机物逐渐向小分子过渡,有效降低了有机物的污染.玉米的根际作用增加了沉积物中的微生物和酶活性.种植玉米较好地修复了受污染河道复合沉积物.

Pot experiment was conducted to study phytoremediation of maize to heavy metal-organic contaminated sewage fiver sediment. Results show maize has different accumulation capacity to different heavy metal. The highest concentration ratio for Zn roaches 56.69 % of total amount in sewage fiver sediment. Accumulated amount in shoot is 1 985.56 mg·kg^-1, accounting for 30.16% of total Zn in sediment. Root accumulating of Pb, Cu, Ni and Cd is larger than shoot. Cd accumulating in root is 2.33 mg·kg^-1 , accounting for 40, 10% of total Cd in sediment. Amount of Zn, Pb, Cu and Ni accumulated in shoot has significant relation with ion exchangeable heavy metal amount, while has no relation with total heavy metal in plant. Some organic contaminants with high molecular weight become small and decompose into simple organic compound which can be easily absorbed by maize. The number of microorganisms and urease activity increase due to effect of maize rhizosphero. All these prove that maize has improved remediation efficiency of complex contaminants in sewage fiver sediment.