| Eutrophication is a main problem of lake pollution presently. When external pollution sources of lakes are controlled, the effects of internal pollution origins may become more important. Clearly, eutrophication may still exist and pose a serious environmental trouble due to possible release of internal loading nutrients from sediments. So a study on contaminative characteristics of estuary sediment is important for tracking pollution sources and controlling Eutrophication of Chaohu Lake.Sources, compositions and characteristics of pollutants from estuarine wetland sediments in the Tongyang River were systematically studied, The blind number theory was used to evaluate the potential ecological risk of heavy metals in the sediments. While 4 controlling cross sections were designed, 19 sampling points were chosen, 57 samples were collected for studying pollution of sediments. Compositions content of nutrient matter and heavy metals of samples were analyzed, using spectrophotometry,atomic absorption method,etc. According to the test data, the relationship between pollution factors were discussed.Research results show that the pollutants in sediments were very unhomogeneous in the spaital distribution, Delamination in sediments was very clear. The content between organic matter and total nitrogen, total nitrogen and total phosphorus, Cu and Zn and Pb in sediments showed a significant correlation, respectively. The organic pollution in surface sediments was light, ON pollution in surface sediments belonged to IV grade, organic index in sediments was higher, sediments fertility grade was subject to III grade. Heavy metals in surface sediments stood in middle pollution degree, the potential ecological risk index was low. The research results show that the application of blind number theory to ecological risk evaluation of pollution sediments was efficient and reliable both in theory and in practice.
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