Heavy metal contamination in suspended solids of Changjiang River — environmental implications

Spatial and temporal changes of contamination of As, Cd, Co, Cr, Cu, Ni, Pb and Zn in sediment and suspended solid during dry and flood seasons were investigated in 75 locations along the Changjiang River basin. As and Cd had higher Igeo values both in sediment and suspended solid of Changjiang River. In a principal component analysis with Varimax rotation, the Panzhihua–Northeast Yunnan and Nanling mining areas were plotted out as the most important heavy metal contamination sources for Changjiang River. Poyang Lake region was contaminated strongly by heavy metals and a clear enrichment of heavy metals in suspended solid occurred in Three Gorges Reservoir. Comparing heavy metals in sediment and suspended solid from main channel and tributaries showed that in flood season, erosion of tributaries increased, and the contamination levels of heavy metals in tributaries were higher than in the main channel.