太湖沉积物中重金属的垂向分布特征及迁移转化.pdf

摘 要：为了解太湖沉积物中重金属污染的变化特征和迁移规律，选取太湖柱状沉积物为研究对象，测定 Cd、Pb、Cu、Cr 4种重金属 的总量及赋存形态，分析重金属在垂向上的分布状况及污染程度。结果表明，金属 Cd、Pb、Cu、Cr的含量随着深度的增加而降低，并在 1950年和 1980年出现拐点，其中 1980年污染最为严重；湖区分布特征表现为西北部梅梁湾、竺山湾和贡湖湾的重金属污染最为严 重，湖心次之；重金属的赋存形态均以残渣态为主，Cd、Pb、Cu、Cr的残渣态分别占 59.74%、81.67%、77.81%、97.56%，除残渣态外，Cd 和 Cu的可交换态含量较高，分别占 15.81%、13.62%，而 Pb的铁锰化物结合态所占比例较高，平均为 11.36%。通过计算淋失比可知， 重金属在上层沉积物中的迁移率较高，而下层沉积物中的重金属较稳定，迁移性较弱；分析重金属的形态迁移可知，表层沉积物中重 金属的可交换态较多，由细颗粒物质等吸附直接沉淀在表层沉积物中，随着泥沙的运动逐渐向下迁移；随着沉积物中铁锰化物的积 累、AVS（酸可挥发性硫化物）积累等环境条件的变化，可交换态向铁锰化物结合态、有机物及硫化物结合态转化。 关键词：太湖；柱状沉积物；重金属；垂向分布；迁移转化 中图分类号：X524 文献标志码：A 文章编号：1672-2043（2016）03-0548-10 doi:10.11654/jaes.2016.03.019 太湖沉积物中重金属的垂向分布特征及迁移转化 杨 陈 员，圆，王沛芳 员，圆*，刘佳佳 员，圆，王 超 员，圆，侯 俊 员，圆，钱 进 员，圆 （1.河海大学浅水湖泊综合治理与资源开发教育部重点实验室，南京 210098；2.河海大学环境学院，南京 210098） Vertical distribution and migration of heavy metals in sediment cores of Taihu Lake YANG Chen1,2, WANG Pei-fang1,2*, LIU Jia-jia1,2, WANG Chao1,2, HOU Jun1,2, QIAN Jin1,2 （1.Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; 2.College of Environment, Hohai University, Nanjing 210098, China） Abstract：Studying the distribution of heavy metals in sediment profiles is of great significance for understanding the pollution history and migration of heavy metals in lake sediments. Here we collected sediment cores from Taihu Lake, and determined total content and fractions of Cd, Pb, Cu, and Cr. The total content of Cd, Pb, Cu, and Cr decreased with increasing depth, with the turning points appeared in 1950 and 1980, especially in 1980. Meiliang bay, Zhushan bay and Gonghu bay suffered from very severe pollution, followed by the central area. The residual fraction of the metals was dominant. The average values of residual Cd, Pb, Cu, and Cr accounted for 59.74%, 81.67%, 77.81% and 59.74% of their total, respectively. The exchangeable Cd and Cu fractions were respectively 15.81% and 13.62%, while the proportion of iron and manganese oxides