Spatial distribution and pollution sources of heavy metals in sediments of Nansi Lake

The objective of this study was to evaluate the spatial distribution, pollution extent and sources of heavy metal in Nansi Lake. Twenty six surface sediments were selected for determination of the total metal content. High concentrations of heavy metals including Cu, Cd, Pb, Zn, Cr, Fe and Mn, ranged from 3.15 to 230000 mg/kg-dry weight (dw). Clustering analysis was used to classify the monitoring sites into 4 main types. Enrichment factors (EFs) were computed for each metal and applied to assess the main polluting metals and the degree of pollution at each site. Paper manufacturing, ships pollution and electroplating wastewaters were found to be the most important sources of heavy metal. Results revealed that serious heavy metal pollution mainly occurred in the Dushan Lake due to shipbuilding and round Weishan island polluted by shipping and petroleum leakage. As for rivers, Guangfu River, Shizhi River and Baima River were most severely polluted ones. Coal chemical, dyeing, chemical fertilize, glass fiber and shipping were main pollution sources.