典型城市污染水体底泥中重金属形态分布和相关性

采用Tessier五步连续提取法,研究了南京市莫愁湖、玄武湖、秦淮河13个底泥样品中的重金属的形态分布情况,分析了重金属浸出量与各形态间的相关性及有机质与有机结合态的相关性,并通过红外谱图分析了有机质与重金属结合的机理.结果表明:底泥中Pb,cu,zh,Ni,Cr主要以有机结合态和残渣态俘在,两种形态的含量占总量70%以上,Zn和Cd的可交换态和碳酸盐结合态含量相列较高,Zn约占20%,Cd约占30%;Zn,Cu,Cd,Ni,Cr的浸出量均与可交换离子态呈现显著的相关性,因此可通过减小可交换离子态含量控制底泥重金属污染的风险性;研究还表明,有机质与有机结合态呈现显著的正相关,因此增加底泥中有机质含量有助于重金属向有_棚结合态转化,有机质与重金属的结合主要是由于其中-些官能团和重金属形成稳定的络合物.

Morphological distribution and correlation of heavy metals in sediment of typical urban polloted water bodies

Morphological distribution of heavy metals including Pb, Cu, Zn, Cd, Ni, Cr were determined by five steps sequential extraction Tessier methods in 13 bottom sediments of Mochou Lake .Xuanwu Lake and Qinhuai river in Nanjing.The correlation between teachability and various morphology,between organic matter and organic matter-bound heavy metals were arialyzed The mechanism of oiganic matter binding with heavy metal was analysed by using infrared spectroaraThe results indicated that Pb, Cu, Zn, Ni, Cr existed mainly in the form of organic- bound and residual, this two forms accounted fin- more than 70% of the total content, Zn and Cd in exchangeable and carbonate-bound phases accounted for a relatively high content, Zn accounted for about 20%, Cd accounted for about 30%;Most of the heavy metal leaching capacity with the exchangeable phases showed a significant correlation, therefore, it can be controlled the risk of sediment heavy metal contamination by reducing the exchangeable ionic content The studies also showed that mere were a significant positive correlation between organic matter and organic-bound, increasing the concent of organic matter in sediments will be helpful to the conversion of heavy metals to organic-bound, the main reason of the conversion is due to stable complex compound formed by some of the functional groups and heavy metals.