天津北塘排污河沉积物的重金属污染及评价

北塘排污河是天津市海河以北市政污水的主要受纳水体,其污染十分严重。该研究于2009年沿河采集其沉积物,调查重金属Zn、Cu、Cr、Pb、Cd和Hg的污染状况。结果表明,沉积物中这6种重金属沿河呈波浪变化,其中Cu和Zn在西碱河入河口处最高,Pb、Cd和Hg在靖江桥处最高,而Cr在京津高速路桥处最高,其平均含量的大小变化顺序为Zn﹥Cu﹥Cr﹥Pb﹥Cd﹥Hg。采用地质累积指数法和潜在生态风险指数法对其评价表明,这6种重金属的整体污染和潜在生态风险均比较严重,京津高速路桥处污染最为严重;靖江桥处风险等级最高,潜在生态风险最大;就整条河而言,重金属污染程度大小顺序为Cd﹥Hg﹥Cu﹥Zn﹥Pb﹥Cr,而潜在生态风险大小顺序为Cd﹥Hg﹥Cu﹥Pb﹥Zn﹥Cr。

Pollution of Heavy Metals and its Assessment in the Sediments of Beitang Drainage River in Tianjin

Beitang Drainage River was the main containing municipal wastewater in north of Haihe River in Tianjin,whose pollution was very serious.In order to studying the pollution condition of six heavy metals(Zn、Cu、Cr、Pb、Cd and Hg) in the sediments of Beitang Drainage River,the sediments were collected in 2009.The results suggested that the six heavy metals changed in waves along the river.The highest contents of Cu,Zn were at the place of Xijian river and those of Pb,Cd,Hg were at Jingjiang Bridge and that of Cr was at the place of Beijing-Tianjin high-speed road.The sequence of average contents for the six heavy metals were Zn>Cu>Cr>Pb>Cd>Hg.The assessment results of geological accumulation index method and potential ecological risk index method suggested that the pollution and potential ecological risk of the six heavy metals in the sediments of Beitang Drainage River.The most serious pollution was at the place of Bridge of Beijin-Tianjin high-speed road and the most potential ecological risk was at the place of Jingjiang Bridge.For the sediments of Beitang Drainage River,the sequence of pollution degree for the six heavy metals was Cd>Hg>Cu>Zn>Pb>Cr,while that of potential ecological risk was Cd>Hg>Cu>Pb>Zn>Cr.