Distribution Characteristics, Pollution Assessment, and Source Identification of Heavy Metals in Sediments of Wetland Lakes

The aims of current study are to asses the levels of heavy metals (Cr, Cu, Ni, Fe, Zn, Co, Pb, and Cd) in sediments of lakes in Yangtze wetland and discuss the relationships between the sources and human activities. A total of 54 samples covering seven lakes along the Yangtze route in Anqing were selected. The concentrations of metals in lake sediments were (mg.kg(-1)): Cr, 4.08 similar to 12.58; Cu, 22.40 similar to 74.36; Ni, 29.89 similar to 142.17; Fe, 22899.20 similar to 50956.40; Zn, 102.31 similar to 242.04; Co, 8.35 similar to 26.89; Pb, 23.38 similar to 88.77; and Cd, 0.29 similar to 2.95. The situation of Xizi Lake was the most serious among the seven lakes investigated. Geoaccumulation index (I-geo) analysis showed that overall risk of heavy metals in sediments was approximately in the order: Cd > Pb = Zn = Cu = Ni > Fe > Co = Cr. The results of principal component analysis (PCA) suggested the main sources of Cd, Cu, Zn, Ni, and Pb on PC 1 were fuel combustion, metal smelting, industrial manufacturing, and other human activities, while Fe on PC 2 originated fromrock weathering and other geochemical processes.