Li Xiao-Lin, Liu En-Feng, Yu Zhen-Zhen, Zhang En-Lou, Lin Qi, Wang Rong, Shen Ji
Collaborative Innovation Center of Human-Nature and Green Development in Universities of Shandong, College of Geography and Environment, Shandong Normal University, Ji'nan 250358, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
Huan Jing Ke Xue. 2019 Feb 8;40(2):614-624. doi: 10.13227/j.hjkx.201805112.
The concentrations of Al, Ti, As, Cd, Cr, Cu, Ni, Pb, Zn, and Hg and chemical speciation of Cd, Cr, Cu, Ni, Pb, and Zn in four short cores sampled from the Yilong Lake, Yunnan Province were analyzed. The vertical and spatial features in the pollution levels and potential ecological risks of heavy metals in the sediments were studied. Except for the wide concentration ranges of Cd, the metals in the sediments showed narrow variations in their concentrations with coefficients of variation less than 0.3. According to the cluster analysis results, all metals could be classified into two groups:metals in group Ⅰ included As, Cd, Hg, and Pb, while metals in group Ⅱ included Al, Ti, Cr, Cu, Ni, and Zn. The metals in each group exhibited similar vertical variations in each core, but their variations were highly different between the cores. The correlation analysis results demonstrated that the variations in metal concentrations in the sediments were greatly regulated by the sediment texture. Therefore, the enrichment factor (EF) method was used for the differentiation of metals from the natural and anthropogenic sources and for the pollution assessment based on the total metal concentrations. The Cd and Pb in the sediments were mainly presented in the reducible speciation with percentages of 48% and 42%, respectively; Cr, Cu, Zn, and Ni were primarily (68%-82%) associated with the residual speciation. Based on the EF and chemical speciation of metals and their enrichment coefficients of the secondary phase, Cd was the typical pollutant with moderate pollution on average, and the other elements were observed in non-to weak pollution levels. Anthropogenic metals were mainly associated with the extractable speciation in the sediment. Combining the ecological risk index, the sediment quality guidelines, as well as the pollution level and chemical speciation of metals, As, Cu, Hg, Ni, Pb, and Zn in the surface sediments of Yilong Lake should have low potential ecological risk. However, Cd may pose a high potential ecological risk.
对采自云南省异龙湖的4个短柱状沉积物岩芯中Al、Ti、As、Cd、Cr、Cu、Ni、Pb、Zn和Hg的含量以及Cd、Cr、Cu、Ni、Pb和Zn的化学形态进行了分析。研究了沉积物中重金属污染水平和潜在生态风险的垂直和空间特征。除Cd含量范围较宽外，沉积物中的金属含量变化较小，变异系数小于0.3。根据聚类分析结果，所有金属可分为两组：Ⅰ组金属包括As、Cd、Hg和Pb，Ⅱ组金属包括Al、Ti、Cr、Cu、Ni和Zn。每组金属在每个岩芯中呈现相似的垂直变化，但不同岩芯之间的变化差异很大。相关性分析结果表明，沉积物中金属含量的变化受沉积物质地的显著影响。因此，采用富集因子（EF）法区分金属的自然源和人为源，并基于总金属含量进行污染评估。沉积物中的Cd和Pb主要以可还原形态存在，分别占48%和42%；Cr、Cu、Zn和Ni主要（68%-82%）与残留形态相关。基于EF、金属化学形态及其次生相富集系数，Cd是典型污染物，平均污染程度为中等，其他元素处于非污染至轻度污染水平。人为来源的金属主要与沉积物中的可提取形态相关。结合生态风险指数、沉积物质量基准以及金属的污染水平和化学形态，异龙湖表层沉积物中的As、Cu、Hg、Ni、Pb和Zn潜在生态风险较低。然而，Cd可能具有较高的潜在生态风险。
