Abstract:
In order to explore the concentrations, distribution characteristics, and ecological risk of heavy metals in the surface sediments of Dongting Lake, the concentrations of seven heavy metals including Cu, Zn, Pb, Cd, Cr, Hg and As from the surface sediments of 21 sample sites of Dongting Lake was collected and determined. The index of geo-accumulation and potential ecological risk were applied to evaluate the heavy metal pollution and potential ecological risk. The results indicated that the concentrations of the 7 heavy metals in the surface sediments exceeded the standard background values in the sediment of Dongting Lake as follow: Cr>Zn>Pb>Cu>As>Cd>Hg. The value of index of geo-accumulation (
Igeo) of heavy metals in the surface sediments followed the order of Cd>Cr>Pb>Cu>As>Zn>Hg, and the value of potential ecological risk followed the order of Hg>Cd>As>Pb>Cu>Cr>Zn. The comprehensive index of geo-accumulation (
Itot) showed serious pollution of heavy metals in the sediments of Zhangshugang site. The potential ecological risk of the whole Dongting Lake was determined as heavy pollution. The potential ecological risk (RI) of the Jiang jiazui, Yugongmiao, Zhangshugang and Potou was higher than 600, which led to serious ecological risk. Zhangshugang site was determined as heavily polluted by two analysis methods, which need to be controlled and remedied soon.