巢湖表层沉积物与上覆水体中重金属分配特征及其相关性研究

Partition characteristics and correlation of heavy metal between sediment and surface water from Chaohu Lake

采集巢湖3个主要支流(南淝河、裕溪河与杭埠河)的河口处表层沉积物和水样各27个,利用ICP-OES及AFS等仪器测试了沉积物中重金属(Cd,Cr,Cu,Pb,Zn,As,Hg)的含量、水体可溶性的重金属含量,并检测了各河流水体理化指标;计算重金属在表层沉积物与水体中的分配系数;分析每个河口处各元素的相关性.结果表明,南淝河口处总氮总磷超过地表水环境质量标准的Ⅴ类,水体中重金属除元素汞以外,含量基本低于Ⅰ类地表水质标准,大部分沉积物样品中重金属的含量均超过背景值.南淝河口处污染最为严重,元素Cr,Cu,Pb,Zn,As的分配系数远低于其他两河口处;杭埠河口的Cd、Hg两元素的分配系数相对较低,且Cu、Cd、Hg三元素的相关性很高.

Twenty seven samples of water and sediment were collected in the three main estuaries（Nanfei River,Yuxi River,and Hangbu River） of Chaohu Lake respectively.The heavy metal（Cd,Cr,Cu,Pb,Zn,As,Hg）contents in the sediment and the dissolved contents in the water were tested with precision instruments such as ICP-OES and AFS,partition coefficients between sediment and surface water were calculated,and any correlation between two elements was analyzed for each estaury.Physical and chemical analysis of water quality indicated that the contents of TN and TP are higher than the limits of the Class Ⅴ environmental quality standard in the rivers.The results of element test showed that the contents of heavy metal elements except mercury are lower than Class Ⅰenvironmental quality standard basically while sediment contents exceed the background values for a great number of sediment samples.The pollution is most serious at the entrance of Nanfei River,partiton coefficients of element Cr,Cu,Pb,Zn and As are lower than those of the others.However,the partition coefficents of heavy metal Cd and Hg are lowest in the Hangbu River,and there is good correlation among the 3 elements of Cu,Cd and Hg.