作　　者： ; ; ; ;

机构地区： 华南农业大学资源环境学院

出　　处： 《环境科学》 2007年第4期852-858,共7页

摘　　要： 针对广州等地城市污泥重金属Zn超标的特点,采用植物处理的方法,将超富集重金属的植物东南景天和低累积作物玉米套种在污泥上,希望在减少污泥重金属的同时,使污泥稳定化和获得合格的农产品.试验采用小区直接种植的方式,3个月后测定植物产量和重金属含量以及处理后污泥的变化,并利用室内盆栽试验初步研究了2种植物根系相互作用的机理.小区试验结果表明,与超富集东南景天单独种植相比,套种显著提高了超富集东南景天提取Zn和Cd的效率,Zn含量达9910mg.kg-1,是单种的1.5倍,而且生产出的玉米籽粒重金属含量符合食品和饲料卫生标准,处理后的污泥生物稳定性明显提高.超富集东南景天和玉米半透膜隔开的盆栽套种试验显示,在套种条件下,玉米对促进超富集东南景天吸收更多的重金属的部分原因是玉米根系降低溶液pH和提高DOC以及Zn/Cd浓度,从而可向超富集东南景天一侧输送更多的水溶态Zn/Cd. The sewage sludge produced in Guangzhou and other cities contains heavy metals such as Zn which exceeds the national standard for agricultural use and should be taken into consideration. A phyto-treatment system consisted of metal hyperaccumulator Sedum alfredii Hance and low-accumulating corn was exploited to phytoextract metals from sludge, in order to reduce heavy metals in sludge and meanwhile to stabilize the sludge and gain innocuous agricultural products. The two plants were co-cropped directly on the sludge plots, the plant biomass and metal uptake were determined as well as the changes of the treated sludge. A pot experiment was conducted to study the interaction mechanisms between the two plant roots. The results of the experiment in plots showed that the efficiency of the phyto-extraction of Zn/Cd by S. alfredii was significantly improved by co-planting and Zn content in S. alfredii reached 9 910 mg· kg^-1 , 1.5 folds of that in the mono- crop. Meanwhile the produced corn grain was conformed to the national standards for foods or feeds concerning heavy metals and the treated sludge was biologically stabilized. The results from the pot experiment studying the interaction mechanisms showed that corn roots, separated from S. alfredii with a mesh barrier, decreased pH in the sludge solution, increased DOC and resulted in higher Zn/Cd concentration than that of S. alfredii mono-crop, which caused more Zn/Cd transported to the S. alfredii side and then enhanced the uptake of the heavy metals by the hyperaccumulator.

关 键 词： 污泥 重金属 植物处理 超富集植物 套种

领　　域： [环境科学与工程]