HEAVY METAL CONCENTRATION IN SURFACE SEDIMENTS OF SHENZHEN TONG-GU WATERWAY AND ASSESSMENT OF POTENTIAL ECOLOGICAL RISK

A survey of surface sediments was carried out in the Tong-gu waterway of Shenzhen in September, 2009. The pollution status of heavy metals was studied and the potential ecological risk assessed by the authors using the index technique of single factor and Hakanson ecological risk index.Results indicate that the sediments are low in concentration of heavy metals, belonging to the first class of sediments in accordance with the GB 18668-2002.The single index suggested that the surface sediments were polluted by Pb, Zn and As.The integrated pollution index for all sampling sites were larger than 5,having reached the moderate pollution level.Pollutants are in an order of Pb > Zn > As > Cu > Cr > Hg > Cd, and potential ecological risks in an order of Hg > As > Cd > Pb > Cu > Cr > Zn.It means that the surface sediments in the Tong-gu waterway of Shenzhen have no immediate ecological risk for the time being.