中国主要水系沉积物中重金属分布特征及来源分析

本文简要综述了中国主要水系沉积物中重金属(Cd、As、Zn、Pb、Cu、Hg、Cr)的分布特征,系统讨论了区域城市化进程对水环境的影响,分析了重金属污染特征及其来源,并采用潜在生态风险指数法评价了中国主要水系沉积物中重金属的潜在生态危害系数和危害指数。结果显示,中国主要水系表层沉积物中重金属的复合污染状况评价结果是:Cd>Hg>Pb>As>Zn>Cr>Cu。其中,Cd元素的Eir值介于41.25～1755.00之间,属于轻微到极强生态危害,其中大部分样点属于强至极强生态危害。Hg元素的Eir值介于115.29～470.83之间,属于强到极强生态危害,其中大部分样点属于很强至极强生态危害。地区对比而言,综合污染状况以海河和珠江较为显著,长江污染最轻。就其来源来讲,海河流域和珠江流域污染来源主要为工业污染,长江和黄河主要是流域岩石风化和土壤侵蚀。

Distribution Characteristics and Source Analysis of Heavy Metals in Sediments of the Main River Systems in China

The distribution characteristics of heavy metals(Cd,As,Zn,Pb,Cu,Hg,Cr) in the sediments of the main river systems in China are described in this study.The authors detailed the influence of urban development on the water environment and the pollution characteristics of heavy metals and their sources,and the potential ecological risk index method in the evaluation of the main heavy metals in sediments from the potential ecological risk coefficient and index of harm.The results showed that the results of composite pollution evaluation for heavy metals in the surface sediments of China’s main river systems are: Cd>Hg>Pb>As>Zn>Cr>Cu.Among them,the Eir values of Cd range from 41.25 to 1755.00,indicative of mild to extremely strong ecological harm.The Eir values of Hg range from 115.29 to 470.83,indicative of strong to extremely strong ecological harm.The water quality of the Haihe River and Pearl River is lowest and the Yangtze River pollution is lightest.The Haihe River and Pearl River are the main sources for industrial pollution,and the Yangtze River and Yellow River are the main factors leading to rock weathering and soil erosion.