深圳市内某河表层沉积物重金属含量及污染评价

2008年11月,从广东省深圳市内某河采集9个(0—5cm)表层沉积物样品,分析其Cu,Cd,Cr,Pb,Zn,Ni,As和Hg的含量和前6种元素的形态分布,并采用潜在生态风险指数法进行污染评价.结果表明,沉积物中Cu和Zn的含量普遍较高,为5.27—1865mg.kg-1和198.4—1275mg.kg-1,其次是Cr,Ni和Pb,为54.39—908.7mg.kg-1、31.3—445.5mg.kg-1和11.63—814.9mg.kg-1,As,Cd和Hg的含量较少;Cd的残余晶格态、Cr的铁/锰氧化态和残余晶格态、Cu的有机结合态和残余晶格态,以及Ni,Pb和Zn的铁/锰氧化态为各元素的主要存在形态;沉积物中Cd和Cu的潜在生态风险普遍较大,9个样品中6个达到Cd极强生态危害,4个达到Cu很强生态危害,有5个样品的重金属混合污染潜在生态风险达到极强生态危害.

CONTENT AND POLLUTION ASSESSMENT OF HEAVY METALS IN THE SURFACE SEDIMENTS OF A RIVER IN SHENZHEN CITY

Nine surface sediments (0-5cm depth) of a river in Shenzhen city were collected in November, 2008.Contents of Cu, Cd, Cr, Pb, Zn, Ni, As and Hg, and their chemical speciations, except As and Hg, were determined.Results indicated that the contents of Cu and Zn were the highest (5.27-1865 and 198.4-1275 mg · kg~(-1)) , followed by Cr, Ni and Pb (54.39-908.7, 31.3-445.5 and 11.63-814.9 mg · kg~(-1)) , and As, Cd and Hg were the lowest The main forms of Cd, Cr and Cu were residue, Fe-Mn oxide bound and residue, and organic matter bound and residue, respectively.Ni, Pb and Zn were mainly bound to Fe-Mn oxides.Heavy metal pollution was evaluated by the method of potential ecological risk index.The results showed that pollution of Cd or Cu was more serious than other heavy metals, 6 out of 9 sediments reaching the strongest ecological harzard of Cd, and 4 reaching the strongest ecological harzard of Cu.The heavy metal combined pollution of 5 sediments reached the very strong ecological harzard.