Effects of sediment dredging on heavy metal removal in Dianchi Lake, China

摘要

The heavy metals (Pb, Zn, Cu, Cd, Cr) and metalloid (As) in surface sediments and water samples from un-dredged and dredged areas in Dianchi Lake had been analyzed to investigate the removal efficiency of sediment dredging. Potential ecological risk index (RI) and simplified geoaccumulation risk index (Igeo) were used to assess the heavy metals accumulation and ecological risks. The results indicated that Pb~(2+), Zn~(2+), Cu~(2+), Cd~(2+), Cr~(2+) and As~(3+) were not detected in water of Dianchi Lake, and the heavy metal content of surface sediments in Caohai Lake was in the order of Zn~(2+)>Pb~(2+)>Cu~(2+)> As~(3+)>Cr~(2+)>Cd~(2+), and that in Waihai Lake was in the order of Zn~(2+)>Pb~(2+)>Cu~(2+)>Cr~(2+)>As~(3+)>Cd~(2+). Through comparing the heavy metal content in sediments from un-dredged and dredged areas, pollutants reduced after sediment dredging, which can be reflected by the Igeo values too. Potential ecological risk index showed that the potential ecological risks were at low level in Dianchi Lake after sediment dredging.