Study On Biological Effectiveness Of The Heavy Metal In The Sediment Of Rivers In Different Functional Areas Of Shanghai

In order to meet the national ecological friendly and the strategic requirements of sustainable development, solve the problem of heavy metals pollution in urban river,understand heavy metal pollution condition in the sediment deeply, Caohe Jing,Tangsi Jing,Baimiao Gang and Malu River in different functional areas of ShangHai were selected. These rivers distribute in dustrial zone, living areas and agricultural areas.The surface sediments and benthic animals in the four rivers were selected as the research objects, total content and forms characteristics of heavy metal Zn, Pb and Cd in each rever and difference of community structure of benthic animals in different rivers were researched, ecological risk assessment of the heavy metal in the sediments with the Index of Geoaccumulation and the ratio of SEM/AVS were studied, which would provide theoretical basis of heavy metals in the sediments of urban rivers. The main results are as follows:(1) The content of Zn, Pb and Cd in the surface sediments of the four rivers are Zn> Pb> Cd in turn, which were more than background value of soil in Shanghai. The content of Zn, Pb and Cd in the surface sediments in Caohe Jing,Tangsi Jing and Malu river, which were located in Shanghai downtown area,had significant difference with Bai miao River.(2) The extracted proportion of the Pb, Zn and Cd in the sediment of the four rivers is higher,so biological validity of the three metals is higher. Pb, Zn and Cd in acid extractable fraction has a significant negative correlation with pH, organic matter fraction of Pb, Zn and Cd has significant correlation with TOC, TS, TN.It also illustrated hydrologic characteristics affected by Huangpu River.(3)9kinds of benthic animals were found in four rivers. And communities structure of the benthic animals in the four rivers had significant difference. Plenty of snails and bivalve mollusks priver clam and clam were found in Bai Miao River. Limnodrilus hoffmeisteri were the dominant species founded in another three rivers. Difference of communities distribution of benthic animal showed the different pollution levels. Contaminated degree of Baimiao River is lowest. Limnodrilus hoffmeisteri and snails both have significant correction with heavy metals in the sidement,which imply that Limnodrilus hoffmeisteri and snails can be the indicators of heavy metals in urban rivers.(4) Ecological risk assessment of the heavy metal in the sediments with the Index of Geoaccumulation and the ratio of SEM/AVS were studied.The results showed that except part samples of Pb pollution level in Baimiao River and Tangsi Jing were low, most samples of Cd, Zn, Pb in the sediment of four rivers were medium pollution level,which should be concerned. The ratios of SEM Pb/AVS, SEM zn/AVS and SEM cd/AVS were less than one, which showed that the three kinds of metal have no potential biological toxicity.