黑麦草对复合污染河道疏浚底泥修复的研究

采用室温盆栽试验,研究了黑麦草(LoliummultiflorumLam)对排污河道疏浚底泥中的重金属(Zn、Pb、Cu、Cd、Ni)-有机物复合污染的修复情况。结果表明,第2次收获(剪切)的黑麦草地上部分积累的重金属Zn、Pb、Cu、Cd的数量均小于第1次收获(剪切),且第2次连根收获发现黑麦草的根部积累了大量的重金属;两次收获地上部分积累的重金属数量和重金属的离子交换态数量有很好的相关性,而与底泥中重金属总量的相关性较差;种植黑麦草后的底泥中重金属的存在形态和晶格结构发生了变化。黑麦草对底泥中的有机污染物有很好的修复作用;在两次收获后的底泥中的有机污染物的降解率达到72.6%,大部分有机物被炭化为CO2和H2O,其中部分难降解的大分子量有机污染物也被植物降解为小分子量的易于被植物吸收的形态,种植黑麦草后底泥的多酚氧化酶和脲酶活性均得到提高。证明黑麦草是修复重金属-有机物复合污染的良好植株。

Phytoremediation of Complex Contaminations in Dredged Sewage River Sediment by Lolium multiflorum Lam

Pot experiment was conducted to study phytoremediation of Lolium multiflorum Lam to heavy metal-organic contaminated dredged sewage river sediment. The results showed that the shoot of the first harvesting which was cut off the sediment surface accumulated more amounts of Zn, Pb, Cu and Cd than the second harvesting. The root of Lolium multiflorum Lam also accumulated large amount of heavy metals. The accumulated amounts of metals in shoot had more direct relation with ion exchangeable metal amount, while had less relation with the total metal amount. Analysis of ESEM and XRD showed that heavy metals configuration and crystal lattice had been changed after planting. The removal rate of organic contaminants reached 72.6%. Most of the organic contaminants were decomposed into CO2 and H2O; and others with high molecular weight were decomposed into simple organic compound which could be easily absorbed by plant. The activity of urease and polyphenol oxidase increased after two growing seasons. All these proved Lolium multiflorum Lam was fit for phytoremediation of heavy metal-organic complex contamination.