Yu Zhen-Zhen, Liu En-Feng, Zhang En-Lou, Lin Qi, Shen Ji, Wang Rong, Li Yan-Ling
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Huan Jing Ke Xue. 2017 Oct 8;38(10):4169-4177. doi: 10.13227/j.hjkx.201702131.
Heavy metals pollution in the sediments is one of the main factors impacting the water quality and ecosystem health. In this study, concentrations of ten metals in nine sediment cores from the Chenghai Lake were determined. Chronology of a typical core (CH2012) was constructed by the Pb and Cs dating method. The spatio-temporal variations in concentrations and contamination characteristics of As, Cd, Cu, Hg, Ni, Pb, and Zn were evaluated. The potential eco-risks of heavy metals in the surface sediments were studied by combining the ecological risk index and sediment quality guidelines (SQGs) assessment as well as their pollution levels (enrichment factors, EF). The metal concentrations in each sediment core showed little vertical change with coefficients of variation of less than 0.20, except for Cd, whose coefficient of variation was 0.59. Spatially, the average concentrations of each metal showed minor difference among the cores, with ratios ranging from 1.2 to 1.8, suggesting similar sedimentary characteristics of metals in the whole lake. Cd and Pb were influenced by anthropogenic contamination that has started in the mid-1980s. The pollution level of Cd decreased in the past decade and still belongs to the moderate pollution degree, whereas the pollution level of Pb increased continually and could be classified as the weak pollution degree. The Hg contamination began in the late 1990s, with EFs ranging from 0.9 to 1.6, belonging to the weak pollution degree. The As, Cu, and Zn pollution occurred mainly near the surface sediments with weak pollution degrees. Spatially, there were no obvious trends in pollution levels of the metals. The heavy metals pollution is mainly influenced by atmospheric deposition that originates from non-ferrous metal smelting emissions, as well as agricultural and domestic discharges. As, Cu, Ni, Pb, and Zn in the surface sediments have low potential ecological risks, whereas Hg and Cd may pose middle-high potential risks.
沉积物中的重金属污染是影响水质和生态系统健康的主要因素之一。本研究测定了程海湖9个沉积物岩芯中10种金属的含量。通过铅和铯测年法构建了一个典型岩芯（CH2012）的年代序列。评估了砷、镉、铜、汞、镍、铅和锌含量的时空变化及污染特征。结合生态风险指数和沉积物质量基准（SQGs）评估及其污染水平（富集因子，EF），研究了表层沉积物中重金属的潜在生态风险。除镉变异系数为0.59外，各沉积物岩芯中的金属含量垂直变化较小，变异系数小于0.20。在空间上，各金属的平均含量在岩芯间差异较小，比值在1.2至1.8之间，表明整个湖泊中金属的沉积特征相似。镉和铅受到始于20世纪80年代中期的人为污染影响。镉的污染水平在过去十年中有所下降，仍属于中度污染程度，而铅的污染水平持续上升，可归类为轻度污染程度。汞污染始于20世纪90年代后期，富集因子在0.9至1.6之间，属于轻度污染程度。砷、铜和锌污染主要发生在表层沉积物附近，污染程度较弱。在空间上，金属的污染水平没有明显趋势。重金属污染主要受有色金属冶炼排放以及农业和生活排放源的大气沉降影响。表层沉积物中的砷、铜、镍、铅和锌具有较低的潜在生态风险，而汞和镉可能构成中高潜在风险。
