A Study On Pollutant Characters And Source Of Sediment In The Estuary Of Shiwuli River In Chaohu Lake

In recent years, the eutrophication of Chaohu lake is becoming more serious, even when the control of exterior pollutant source is under processing, sediments are still leading to negative influence on the quality of waters in the long times. Therefore, the research on the sediment pollution situation is of great importance theoretically and practically for understanding interior pollutant source, casting back to the original pollution, improving the eutrophication of Chaohu lake, and bringing forward solutions to reduce the pollutant.Taking the sedimentary area in the estuary of the Shiwuli River in Chaohu lake as object, this article researches on the sources, component and the distributing features of the sediments in this area systematically, and evaluates the potential ecological risk of the pollutants of the heavy metals in these sediments.The research is based on 6 control sections ,18 sampling spots, 64 sediment samples in the estuary area different layers to study the substantial components as well as the nutrimental contents, and the heavy metal contents in the sediments. The total nitrogen, total phosphorus, organic contents and heavy metal contained in these samples were then tested through X -diffraction and atomic absorption spectrophotometry;at last, the correlative relations of the polluted factors and the fertility of the sediments were analyzed. In addition, some hydrophytes were collected to determine the total nitrogen, total phosphorus, organic content and heavy metal contained in them, to make analysis on the correlation between hydrophyte pollutants and sediment pollutant contents of the sedimentary layer.Conclusion: the delamination of the sediments is obvious, which include serious pollution layer, pollution transition layer, and the normal lake sedimentary layer from top to bottom. The sediments pollutant mainly concentrates on the severity pollution layer. The content of all the pollutants decreases obviously in the transition layer, which could be explained as that the sediments pollution is caused by the pollution in resent years. The content of the total nitrogen, total phosphorus and heavy metals contained in the sediments and in the hydrophyte is presented as positive relativity, namely TP>TN>Cr>Pb>Cd. The pollutant degree of the heavy metal in the sediment is: mercury, chromium, plumbum, copper, cadmium, whichmeans a medium potential ecological risk. The ratio of nitrogen to phosphorus in the sediments indicates that the lake is in the state of eutrophication, and the organic roots possibly in the hydrophytes.