A Study Of The Pollutants In The Dredging Sediments From Chaohu Lake And The Ecological Risk Assessment In The Eastern Of Shuangqiao River

Currently, the sediment dredging engineering is an important technology of eutrophication control in lakes. Because of a large volume of the dredging sediments and an ecological hazard of the heavy metals, how to deal with these sediment was therefore a technical problem of the dredging.The composition and distribution characteristics of the pollutants were studied and the potential ecological risk of heavy metals pollution was assessed. Taking the dredging sediments from Chaohu Lake in the eastern of Shuangqiao River as object, the accumulation ability and transportable ability of heavy metals by plants that growed on the dredging sediments were made. From the above research worth some conclusions:(1) The average content of the heavy metals in the dredging sediments shows that the content of Zn reached the largest with 59.145μg/g, and the content of Hg the smallest with only reached 0.035μg/g. The contents of the heavy metals were decresed in the order: Zn >Cr>Cu>Pb>As>Cd>Hg. The contents of Pb, Zn, Cr, Cu were decresed 54.5%, 45.6%, 49.0%, 73.0% before dredging.(2) By the correlation can be learned that the organic matter and the total nitrogen showed a good correlation with a high degree of correlation.The linear equation was y = 457.7x +29.352, the correlation coefficient was R = 0.8526.An Organic matter and the total phosphorus also showed a positive correlation, the linear equation was y = 226.47x +258.16 and the correlation coefficient was R = 0.7922.(3) Generally speaking, Cu and Zn, Cu and Al, Zn and Al had a very high correlation, the correlation coefficient of Cu and Zn was 0.9551. As and Hg had the minimum correlation, the correlation coefficient only was 0.2140. The ecological risks of pollutants were decreased in the order of Hg> As>Cd>Cu>Pb>Cr> Zn, which meaned a medium potential ecological risk.(4) The content of TN of the surface part in the reed, the cotton, the cole and the leek of TN were larger than that in the underground portion; And the contents of Cu, Zn, As, Hg of the surface part in the reed, the cole and the leek were less than the corresponding elements' contents of the underground portion. The contents of the TP of the surface part in the reed, the cole were larger than that in the underground portion and the surface content of TP of the leek was larger than that underground portion. The surface contents of the TP, Cu, Zn, As, Hg in the cotton were larger than the corresponding elements' contents of the underground portion. The accumulative abilities of heavy metals in plants were decreased in the order: Hg>Zn>Cu>As. The potential ecological risk of heavy metals in plants were decreased in the order: Hg>As>Cu>Zn.