基于统计的百花湖表层水中重金属分布特征

摘要

以云贵高原深水湖泊百花湖为研究对象,研究其表层水中9种重金属(As,Hg,Cd,Pb,Fe,Cu,Zn,Mn和Cr)的分布特征并开展溯源研究.结果表明:各采样点之间重金属含量变化较大,变异系数为5.6%～147%,同一采样点水质中重金属元素含量变化顺序为Fe>Mn>Cr>Zn>Cu>As>Pb>Hg>Cd;地统计分析从空间角度表明百花湖不同水域重金属含量分布差异较大;ρ(Ca)与ρ(Cu),ρ(Pb)的相关系数(R2)分别为-0.771(P<0.01)和-0.692(P<0.05);主成分分析揭示了该湖泊水体重金属含量主要受4个因素的影响(分别解释了总因子的33.88%,19.32%,18.02%和11.81%),其中一些重金属同时受2个以上主成分因素的影响;聚类分析将这9种重金属归为4类,Fe单独为一类,Cd,Pb,Hg,As和Cu为一类,Zn,Cr为一类,Mn独自为一类.地统计分析、相关性分析、主成分分析和聚类分析的应用使得影响因素复杂的水环境问题的研究相对简单化.%Nine heavy metals (As, Hg, Cd, Pb, Fe, Cu, Zn, Mn and Cr) in the surface water of Baihua Lake, which is a deepwater lake located on the Yunnan-Guizhou Plateau, were analyzed to study their distribution characteristics and origins. The results showed that the concentrations of certain heavy metals varied at different sampling sites, with the RSD ranging from 5.6％ to 147％. The mass concentrations of these heavy metals in the same sampling sites followed the order of Fe ＞ Mn ＞ Cr ＞ Zn ＞ Cu ＞ As ＞ Pb ＞ Hg ＞ Cd. Geostatistical analysis indicated that, from the spatial point of view, there were no significant correlations between the concentrations of these metals occurring in the surface water. However, Cu and Pb showed some significant negative correlations with Ca, with R2 values of - 0. 771 ( P ＜ 0. 01 ) and - 0. 692 ( P ＜ 0. 05 ), respectively. Principal Component Analysis (PCA) was applied to study the origins of these heavy metals; the analysis revealed that four components ( representing 33.88％ ,19. 32％ , 18.02％ and 11.81％ of total variance, respectively) were extracted based on concentrations of these elements in water samples. Some heavy metals were affected by two or more component factors. In addition, these nine heavy metals were classified into four groups via Hierarchical Cluster Analysis (HCA). The first group included Cd, Pb, Hg, As and Cu, and the second group included Zn and Ct, while Fe and Mn were classified into the third and fourth groups. Application of geostatistical analysis, correlation analysis, PCA and HCA makes the analysis of complex environmental factors simpler.