珠江磨刀门河口表层沉积物中重金属含量及其分布特征

分析了在珠江磨刀门河口采集的37个表层沉积物样品重金属(Cu、Pb、Zn、Cr、Cd、Hg、As、Ni)的含量及分布特征。采用原子吸收法分析了Cu、Pb、Zn、Cr、Cd、Ni的含量,采用冷原子吸收法分析了Hg、As含量。结果表明,口门处及其两侧和拦门沙内坡重金属的含量最高;外海区域重金属含量普遍较低;由口内河床至口门处,Cu、Cr、Hg、As的含量减小,Pb、Cd、Zn、Ni的含量逐渐增大;大部分重金属(Cu、Pb、Zn、Cd、As、Ni)的含量由口门处至拦门沙地区是先减小再增大的;由拦门沙至外海,Cu、Pb、Cd、As的含量减小,Zn和Ni的含量先减小后增大;由口门处至外海,Cr和Hg含量的总体趋势是增大的。磨刀门河口表层沉积物中重金属元素含量与CEC、小于0.001mm粘粒以及沉积物有机质含量的相关性均达到显著或极显著水平;重金属含量与沉积物pH值的相关性不显著;重金属元素的含量变化和分布规律还表明磨刀门表层沉积物的重金属主要受陆源污染物的影响。

Concentrations and content distribution of heavy metals in surface sediments in Modaomen distributary mouth of Pearl River estuary

A preliminary study on 8 kinds of heavy metals including Cu,Pb,Zn,Cr,Cd,Hg,As and Ni has been conducted in the Modaomen distributary mouth of the Pearl River estuary.37 representative samples were analyzed,and the results show that most of the heavy metals have the highest content on both sides of the estuary and near the inner sandbar;from the riverbed to the estuary,the content of Cu,Cr,Hg and As decreases and the content of Pb,Cd,Zn and Ni augments;most of the heavy metals' content from the estuary to the sandbar is from low to high;from the sandbar to the open-sea,the content of Cu,Pb,Cd and As is from high to low,but the content of Zn and Ni decreases and then augments again;from the estuary to the open-sea,the trend of the content of Cr and Hg is increscent.The content distribution of heavy metal correlate well with CEC,clay(<0.001 mm)and organics,and it can be concluded that they are influenced by pollutants carried over long distance from land sources.