ICP-OES研究北运河表层沉积物中重金属的空间分布特征及生态风险评价  

Distribution Characteristics and Ecological Risk Assessment of Heavy Metals in Surface Sediments of the North Canal Using ICP-OES

作　　者：刘蔚怡 孟媛 靳百川 蒋梦云 蔺祖弘 胡立扬 张婷婷[1] LIU Wei-yi;MENG Yuan;JIN Bai-chuan;JIANG Meng-yun;LIN Zu-hong;HU Li-yang;ZHANG Ting-ting(College of Chemical Engineering,Beijing University of Chemical Technology,Beijing 100029,China)

机构地区：[1]北京化工大学化学工程学院,北京100029

出　　处：《光谱学与光谱分析》2020年第12期3912-3918,共7页Spectroscopy and Spectral Analysis

基　　金：水体污染控制与治理科技重大专项(2018ZX07111003)资助。

摘　　要：水系沉积物中重金属元素的生态风险评价对流域重金属的污染程度和迁移转化规律等研究具有十分重要的意义。北运河是京津冀地区重要的纳污河道,全流域重金属的分布特征和生态风险尚不清楚。为全面了解北运河全流域沉积物中重金属的赋存水平,该研究在上、中、下游共选取17个国控及省控断面采集表层沉积物。使用王水提取-水浴消解以及连续提取法对沉积物样品进行前处理,电感耦合等离子体发射光谱法(ICP-OES)同时测定As, Cd, Cr, Cu, Mn, Ni, Pb和Zn八种元素的含量及形态,并对其进行生态风险评价。结果表明,北运河表层沉积物中重金属平均含量为Mn>Pb>Zn>Cu>Cr>Ni>Cd>As。重金属元素Pb, Zn和Cu平均含量高于背景值,其中Pb元素平均含量为背景值4倍以上。不同重金属空间变化差异性较大,中下游含量相对较高。通过形态分析发现, Cd和Zn元素的形态以酸可溶态和可还原态为主,生物活性较强,对环境危害较大;As, Mn, Cr, Cu,Ni和Pb元素的形态以可氧化态和残渣态为主,生物活性较弱,对环境危害较小。地质累积指数(I(geo))表明重金属外源污染严重, Pb(I(geo)=2.24)污染水平较重, Cu(I(geo)=1.44)和Cd(I(geo)=1.45)污染水平中等, Zn(I(geo)=0.99)污染水平较轻,其他元素均处于无污染水平。潜在生态风险指数表明,北运河流域表层沉积物重金属的综合生态风险较低,仅有Cd元素的存在使北运河具有中等风险,其他元素均未给北运河带来风险(低风险)。主成分分析表明北运河流域表层沉积物重金属主要来源于农药和化肥的不合理使用、大气沉降以及工业与交通的排放。与我国其他典型流域相比,北运河流域表层沉积物重金属含量相对较低,这主要归因于近些年来京津冀地区产业结构调整、大气污染控制以及河道修复工作的有效实施,该研究可为后续北运河治理和管理提供数据支持。The ecological risk assessments of heavy metal in river sediments is of great significance to study heavy metals pollution level,migration and transformation.The North Canal is an important sink in the Beijing-Tianjin-Hebei region,but the distribution characteristics and ecological risk assessments in the whole river are less known.In order to survey the occurrence of heavy metals in the sediments of the whole basin,17 national and provincial control sections were selected from the upper,middle and lower reaches of the North Canal.Sediment samples were pretreated by aqua regia extraction,water bath digestion and BCR extraction.The contents of As,Cd,Cr,Cu,Mn,Ni,Pb,and Zn were measured by inductively coupled plasma emission spectroscopy(ICP-OES).The results indicated that the average content of heavy metals in the surface sediments declined as the following order Mn,Pb,Zn,Cu,Cr,Ni,Cd,As.The contents of Pb,Zn and Cu were higher than background values.It is noteworthy that the average value of Pb was 4 times more than their background value.Moreover,the values of different heavy metals varied significantly with the spatial reaches,and the contents in middle and lower reaches are relatively high.The metal speciation analysis indicated that Cd and Zn in the sediments were dominated by acid soluble and reducible species,and have high mobility and bioavailability.While As,Cr,Cu,Mn,Ni and Pb in the sediments were dominated by oxidizable and residual species,and have weak biological activities and pose little harm to the environment.The geological accumulative index(I geo)indicates that anthropogenic sources mainly contaminated the surface sediments of heavy metals.Pb(I geo=2.24)reaches the level of moderately to heavily polluted,Cu(I geo=1.44)and Cr(I geo=1.45)reaches the level of moderately polluted,Zn(I geo=0.99)reaches the level of unpolluted to moderately polluted.The calculated values of I geo for As,Cr,Mn and Ni were less than 0,indicating that As,Cr,Mn and Ni are all at practically unpolluted levels.The potential e

关 键 词：ICP-OES 沉积物 重金属 形态分析 风险评价 源解析 

分 类 号：O657.3[理学—分析化学]