Abstract: To understand the status of heavy metal pollution in sediments in Hongfeng Reservoir, a total of 80 sediment samples were collected from eight sites. The concentrations of Hg, As, Zn, Pb, Cd, Cr, Cu and Ni were analyzed using atomic fluorescence spectrometer and atomic absorption spectrometer. The pollution status was evaluated by geoaccumulation index (I_geo) and potential ecological risk index (RI). Meanwhile, correlation analysis was carried out and the sources of pollution were discussed. The results showed that the concentrations of heavy metals in the sediments of the North Lake of Hongfeng Reservoir were significantly higher than those in South Lake. The average concentrations of Hg, As, Pb, Cd, Cr, Cu, Zn and Ni were 0.56, 35.76, 43.66, 0.50, 91.03, 89.14, 152.44 and 109.30 mg·kg^-1, respectively. Based on the soil background value of Guizhou Province, the results of I_geo evaluation showed that Hg was in a moderate pollution, and the pollution order was Hg>Ni>Cu>As>Zn>Pb>Cr>Cd. The RI evaluation results showed that Hongfeng Reservoir was in a medium ecological risk. There were three sources for the heavy metal pollution of Hongfeng Reservoir. Industrial emissions were the main source of Pb, Zn and Cd for North Lake and Central Lake. Urban emissions and the remaining of pesticides and chemical fertilizers surrounding the reservoir were the main source of Cr, Ni, As and Cu for North Lake. The Hg and As mainly came from mining activity for the whole reservoir.

Key words: Alpine grassland, Grazing sheep, Nutrition