珠江口沉积物中重金属形态分布特征研究

Content and Distribution Character of Forms of Heavy Metals in Sediment in Pearl River Estuary

测定了珠江入海口沉积物中的重金属镉、铬、铜、铅、锌的含量,并采用Tessier形态分类法对镉、铬、铜、铅、锌在沉积物中的存在形态进行了提取和测定。结果表明,珠江口沉积物中镉、铬、铜、铅、锌的含量与国内其他河口相比,处于一种较高的含量水平。与珠江三角洲土壤背景值相比,镉、铬、铜、铅、锌在沉积物中有不同程度的富集,其中以镉的富集系数最大,为12.67,表明镉的污染比较严重。各种重金属的主要存在形态不同,镉以可交换态为主,占总量的27.63%;铬以残渣态为主,占总量的51.92%;,铜以有机态为主,占总量的81.27%;铅以残渣态为主,占总量的52.60%;锌则以铁/锰态为主,占总量的61.40%。

The content of heavy metals Cd,Cr,Cu,Pb and Zn in sediment in Pearl River estuary are determined.Five forms of heavy metals in sediment are extracted and determined with Tessier morphological taxonomy.The result shows that the sum of Cd,Cr,Cu,Pb and Zn in sediment in Pearl River estuary are higher than the background value of soil,and the enrichment ratio of Cd is greatest reaching to 12.67,and it shows that the Cd pollution is very severe.Different heavy metals have different forms,Cd is existed as exchangeable form and the proportion is 27.63%.Cr is existed as residual form and the proportion is 51.92%,Cu is existed as organic form the proportion is 81.27%,Pb is existed as residual form and the proportion is 52.60%,Zn is existed as Fe-Mn form and proportion is 61.40%.