包头市区道路可悬浮灰尘重金属污染及来源研究

Study on Pollution and Source of Heavy Metals in the Re-suspended Road Dust from Baotou Urban Area, China

为了解包头市区道路可悬浮灰尘重金属的污染及来源,作者采集了包头市区道路灰尘样品,利用X射线荧光光谱仪测定可悬浮灰尘(粒径<100μm)中Cu、Pb、Zn、Cr、Co、V、Ba、Mn和Ni的含量,采用单项污染指数法和内梅罗综合污染指数法评价可悬浮灰尘中重金属的污染水平,运用相关分析、主成分分析、聚类分析等多元统计学方法识别重金属的可能来源,利用主成分分析-多元线性回归受体模型解析不同来源对道路可悬浮灰尘中重金属的贡献。结果表明,包头市区道路可悬浮灰尘中除Ni外,其他重金属的含量均高于当地土壤背景值。道路可悬浮灰尘中Co和Cr主要呈现重度污染,Pb主要呈现中度-重度污染,Ba和Cu主要呈现轻度-中度污染,V主要呈现轻度污染,Mn、Ni和Zn主要呈现未污染-轻度污染,综合污染评价结果显示包头市区道路可悬浮灰尘中重金属呈现重度污染。多元统计分析结果表明,Ba、Pb和Zn显著正相关,属于同一主成分,且在聚类分析中为同一类;V、Mn、Ni、Cu和Cr为同一类、同一主成分,且显著正相关;Co与其他重金属不相关。结合样品中各重金属元素的含量、分布特征,推断出包头市区道路可悬浮灰尘中的重金属主要有3种来源:V、Mn、Ni、Cu和Cr主要来自自然与工业混合源,Ba、Pb和Zn主要来源于化石燃料-交通源,Co主要来自建筑源。自然与工业混合源、化石燃料-交通源及建筑源对包头市区道路可悬浮灰尘中重金属的贡献分别为34.8%、62.6%和2.6%。研究表明包头市道路可悬浮灰尘中重金属污染严重,化石燃料、交通和工业排放是造成环境污染的主要来源。

To understand the pollution and source of heavy metals in the re-suspended road dust of Baotou,road dust samples were collected from the urban area and the contents of Cu,Pb,Zn,Cr,Co,V,Ba,Mn and Ni in the re-suspended road dust(<100μm particles)were determined by X-Ray fluorescence spectrometry.The pollution levels of heavy metals investigated in the re-suspended road dust were evaluated using single pollution index and Nemerow comprehensive pollution index.Their possible sources were identified by multivariate statistical analysis methods including correlation analysis,principal component analysis and cluster analysis,and the contributions of each source to heavy metals in the dusts were apportioned by principal component analysis-multiple linear regression receptor model.The results showed that the contents of all analyzed heavy metals except for Ni in the re-suspended road dust of Baotou were higher than their background values in local soil.Co and Cr were heavily polluted,Pb was moderately to heavily polluted,Ba and Cu were lightly to moderately polluted,while V was lightly polluted and Mn,Ni and Zn were unpolluted to lightly polluted.The assessment results of comprehensive pollution indicated that heavy metals were heavily polluted in the re-suspended road dust of urban area.The multivariate statistical analysis results show that Ba,Pb and Zn are significantly positive correlation.They belong to a principal component and are clustered to a cluster.V,Mn,Ni,Cu and Cr belong to a cluster and a principal component and are significantly positive correlation.Co and other heavy metals are uncorrelated.Three main sources of heavy metals measured in the re-suspended road dust from urban area were identified based on correlation analysis,principal component analysis and cluster analysis,as well as the content characteristics of heavy metals,i.e.,Ba,Pb and Zn were mainly from fossil fuel-traffic source;V,Mn,Ni,Cu and Cr principally originated from natural and industrial mixing source,while Co mainly originated from construction source.The contributions of natural and industrial mixing source,fossil fuel source-traffic and construction source to heavy metals in the re-suspended road dust from urban area were 34.8%,62.6%and 2.6%,respectively.