Distributing characteristics of heavy metal elements in the sediment profiles of Bijiang River, western Yunnan, China

Heavy metals in the sediments profiles of Bijiang River are analyzed by sequential extraction procedure, and the distribution and the speciation analysis of heavy metals show that 75km section of the Bijiang River away from Jinding Pb-Zn deposit is polluted by heavy metals in the sediments, and Cd pollution is much worse. Assessment of these ecological risks shows that the potential ecological hazards of heavy metals in the upper sediment are middle to very high degree. The main factor causing ecological hazards is Cd, and then followed by Pb, As, zn.