海西城市群PM2.5中重金属元素的污染特征及健康风险评价

采集2010~2011年海西城市群PM_(2.5)样品,用粒子激发-X射线发射技术(PIXE)方法测试样品中痕量重金属(Zn、Cu、Pb、Mn、Ni、Cr、As)的浓度,分析痕量重金属的污染特征、富集程度和来源,并进行重金属对人体健康风险的评价.结果表明,PM_(2.5)中重金属总浓度的时空分布特征与PM_(2.5)的不一致,这与PM_(2.5)的某些主要贡献源(如建筑尘和扬尘等)并非痕量重金属的贡献源有关.PM_(2.5)中Zn、Cu、Pb、Mn、Ni、Cr、As等重金属的EF值均高于10,呈明显的人为源富集现象.主成分-多元线性回归(PCA-MLR)解析结果显示,PM_(2.5)中痕量重金属主要有3种来源,即燃煤和机动车尾气(70.59%)、混合源(燃煤、燃油和冶炼行业,17.55%)以及其他工业源(11.86%).健康风险评价结果显示,PM_(2.5)中致癌重金属(Ni、Cr、As)的风险值高于非致癌重金属(Zn、Cu、Pb、Mn)风险值,但均低于一般可接受风险水平(10-6),说明海西城市群大气环境PM_(2.5)中重金属未对人体健康造成危害.

Pollution Characteristics of Heavy Metals in PM2.5 and Their Human Health Risks Among the Coastal City Group Along Western Taiwan Straits Region, China

PM_2.5 samples were collected from 11 sampling sites in the coastal city group along western Taiwan Straits region, China, and these heavy metal elements (Zn, Cu, Pb, Ni, Cr, As) were detected using particle-induced X-ray emission (PIXE) method. The pollution characteristics, enrichment factors and source apportionment of heavy metals in PM_2.5 were analyzed, and furthermore, their human health risks were determined. The result showed concentration distribution was obviously different between PM_2.5 and heavy metals in the city group, for the main sources (e.g. construction dust and ground dust) for PM_2.5 were not the main contribution to these heavy metals. The enrichment factors of Zn, Cu, Pb, Mn, Ni, Cr, As exceeded 10, which suggested these metals were enriched and significantly impacted by anthropogenic pollution. Three main groups of heavy metals in PM_2.5 were identified by principal component analysis (PCA-MLR), such as coal combustion and traffic emissions (70.59%), multiple sources (coal and oil combustion, pyrometallurgical process, 17.55%) and other industry (11.86%). The risk levels for carcinogenic heavy metals (Ni, Cr, As) and non-carcinogenic heavy metals (Zn, Cu, Pb, Mn) were lower than the average level of risk acceptance (10^-6), which suggested these heavy metals did not cause harm to human health in these cities.