湘江下游河床沉积物元素地球化学背景值估算  

Geochemical background of elements in bed sediments from lower reaches of the Xiangjiang River in Hunan Province,China

作　　者：赵亚方 彭渤[1,2] 方小红[1,3] 邬思成 刘静 陈丹婷 戴亚南[1,2] ZHAO Yafang;PENG Bo;FANG Xiaohong;WU Sicheng;LIU Jing;CHEN Danting;DAI Yanan(Faculty of Resource and Environment Sciences,Hunan Normal University,Changsha,410081;Key Laboratory of Environmental Heavy-Metal Contamination and Ecological Remediation,Hunan Normal University,Changsha,410081;College of City and Tourism,Hengyang Normal University,Hengyang,Hunan,421000)

机构地区：[1]湖南师范大学资源与环境科学学院,长沙410081 [2]湖南师范大学环境重金属污染机理与生态修复实验室,长沙410081 [3]衡阳师范学院城市与旅游学院,湖南衡阳421000

出　　处：《地质论评》2021年第2期504-522,共19页Geological Review

基　　金：湖南省一流学科(地理学)建设项目;湖南省高校科技创新团队支持计划项目(2014);国家自然科学基金资助项目(编号:41073095)的成果。

摘　　要：本研究对湘江下游河床沉积物进行了元素地球化学分析,在认识沉积物元素地球化学特征、甄别人为源与自然源重金属的基础上,估算了沉积物的元素地球化学背景值。结果表明:SiO2、TiO2、Al2O3、Fe2O3、K2O等主量元素及V、Co、Cr、Ba、Sc、U、Sr、Ga、Ge、Rb、Nb、Y、REE等微量元素在沉积物中含量变化相对稳定(Cv<0.2),分布相对均匀,且富集不明显(EF<2.0,Sr明显亏损)。而MnO、MgO、CaO、Na2O、P2O5等主量元素,及Cd、Mn、Cu、Pb、Zn等重金属在沉积物中含量变化大(Cv>0.25),分布极不均匀,且沉积物中重金属明显富集(EF>2.0)。主成分及Pearson线性相关性分析显示,沉积物中不明显富集的微量元素主要赋存于难溶硅酸盐矿物相中,为自然源元素。而沉积物中显著富集的重金属主要赋存于铁—锰氧化物等矿物相中,为有人为源叠加的元素。故针对不同来源特征的元素用不同的方法进行了背景值计算,求得沉积物中47个元素的背景值。再利用元素比值等方法对所得背景值进行检验。结果表明,本文得到的湘江沉积物元素背景值合理,可用作流域沉积物重金属污染评价参考。Objectives:The objective of this study is to establish the background values of major and trace elements in sediments of the Xiangjiang River by understanding the element composition of the sediments,and discriminating between the natural and anthropogenic sources of heavy metals in the sediments.Thus,the geochemical background values of elements with different sources in the sediments were calculated by using different estimating methods.Methods:Samples for this study were collected from sedimentary cores obtained by drilling into the bed sediments of the river,then the major and trace elements were analysed using XRF and ICP-MS techniques,respectively.Principal component analysis(PCA)and enrichment factor(EF)values were used to identify element sources.For elements from natural sources,this study used reference element(Al2O3)regression analysis,Tukey’s boxplots of local EF etc.,to eliminate outlier values and calculate the background values of elements.For elements with input of anthropogenic sources,the cumulative distribution function(CDF)curve was used after the calculations of regression analysis and Tukey’s boxplots of local EF to eliminate the samples that were polluted by human activities.Results:The results suggest that major elements SiO2,Ti O2,Al2O3,Fe2O3,and K2O,and trace elements V,Co,Cr,Ba,Sc,Th,U,Sr,Ga,Ge,Rb,Nb,Y,and REE relatively have less variation(Cv<0.20)of concentrations in the sediments,and they are believed to be homogeneously distributed in the sediments.These elements do not show significant enrichment or depletion features in the sediments(EF<2.0,except the depletion of Sr).While,major elements MnO,MgO,CaO,Na2O,and P2O5,and heavy metals Cd,Mn,Cu,Pb,and Zn generally have considerably high variation(Cv>0.25)of concentrations in the sediments,and they were distributed very heterogeneously in the sediments,among which the heavy metals are significantly higher enriched(EF>2.0)if compared to that of the NASC.Conclusions:The principal component analysis(PCA)and Pearson’s correlation anal

关 键 词：自然源 人为源 元素背景值 河床沉积物 湘江 

分 类 号：P512.2[天文地球—地质学] P595