广东红海湾海域表层水环境中重金属含量特征及污染评价

The content and pollution evaluation of heavy metals in the surface seawater in Honghai bay

为了研究红海湾海域水体中重金属的污染水平,2015年5月和11月在研究海域设48个采样站位进行了表层水样分析,分析了Cu、Pb、Zn、Cd、Cr、Hg和As共7种重金属的含量及污染特征,采用单因子污染指数评价法和综合污染评价法对研究海域的水质污染情况进行评价分析,利用变异系数法来分析了各调查站位之间污染物在空间尺度上离散程度,使用相关性分析和PCA方法分析重金属污染物的主要来源。结果表明,该海域表层海水中Cu、Pb、Zn、Cd、Cr、Hg和As含量的平均值均满足《海水水质标准》二类水质要求,单因子污染指数法评价结果显示7种重金属平均含量的污染程度大体排序为:Zn>Pb>Cu>As>Cd>Cr>Hg。综合污染评价法显示评价海域表层海水中7种重金属综合污染指数的平均值均小于1,且综合污染指数整体相差不大,研究海域属于清洁海域。变异系数结果表明各站位间水体中重金属含量在调查海域空间离散度较大,研究海域的重金属污染物来自不同的污染源。相关性分析和PCA方法分析表明,重金属元素Cu、Pb、Zn、Cd、Cr、Hg和As之间的相关系数较小,且前三个主分中的研究重金属元素正载荷较低,因此重金属元素相互之间都不具有相似的污染水平或共同的污染来源,元素之间具有共同来源的概率较低。

Surface seawater samples were collected to study the concentration and pollution characteristics of seven heavy metals （ Cu, Pb, Zn, Cd, Cr, Hg and As） in the area at 48 sites in the offshore area of Honghai bay in May and November 2015. The heavy metals pollution condition was evaluated using water pollution index and combined pollu- tion index, and the coefficient of variation （CV） method was used to analyze the dispersion degree of pollutants in spa- tial scale,and the correlation analysis and PCA method were used to analyze the main sources of heavy metals pollu- tants. The results showed that the average concentrations of Cu, Pb, Zn, Cd, Cr, Hg and As met the second grade of seawater quality standard. The Single Factor Pollution Index （SFPI） values of seven metals were in the following or- der：Zn 〉 Pb 〉 Cu 〉 As 〉 Cd 〉 Cr 〉 Hg. The evaluation result of the combined pollution index method showed that theindex grade was relatively low and the value had little difference, so the study area was clean. The results of coefficient of variation （CV） showed that the spatial dispersion of heavy metal content in the investigated area was large,and the sources of heavy metal pollutants in the studied sea area were different. The results of correlation analysis and principal component analysis indicated that the correlation coefficients of Cu,Pb,Zn, Cd, Cr, Hg and As were relatively small, and the first three principal components had lower positive load of heavy metals. Therefore, there were no similar pollution levels or same sources between seven metals, that is, the probability of the same sources was lower among the elenlelltS.