石家庄采暖季道路降尘PM2.5中元素分析及生态风险评价

为了解石家庄采暖季铺装道路降尘中元素污染状况及生态风险,利用降尘缸收集市区4种类型道路的降尘样品,分析降尘PM_(2.5)中Na、K、Cr、Ni、Cu、Zn、As、Pb、Al、Mg、Ca、Fe、Si等13种元素在不同类型道路、不同高度的含量特征,采用富集因子、主因子分析推测PM_(2.5)中元素来源,用潜在生态风险指数法评价重金属元素的生态风险.结果表明,主干道和支路降尘中元素含量最高,快速路最低,地壳元素Al、Si、K、Na更易在1.5 m高处富集,2.5 m高处多人为污染元素如Cr、Ni、Cu、Zn、As、Pb;富集因子和主成分分析显示采暖季道路降尘PM_(2.5)元素来源于燃煤燃油、交通(机动车尾气排放及零件老化磨损、轮胎磨损、道路扬尘)、建筑扬尘和生物质燃烧;富集因子范围0.35~100.45,地壳元素无富集,Cr富集因子平均值达100,生态风险指数高达320,富集程度极强且生态风险指数最大,应该引起足够重视.

Element analysis and ecological risk assessment on road dust PM2.5 from Shijiazhuang during heating season

In order to clarify the pollution situation and ecological risk of elements from city paved roads in Shijiazhuang during heating season, road dust samples were collected from 4 types of roads in urban area, and content of elements such as Na, K, Cr, Ni, Cu, Zn, As, Pb, Al, Mg, Ca, Fe and Si in PM_2.5 at different height and different road types were analyzed. The sources of elements in PM_2.5 were estimated by means of enrichment factor analysis and principal component analysis. The ecological risk of heavy metal was evaluated by potential ecological risk index. The results showed that content of elements in branch roads and main roads were generally high, while expressways were the lowest. Earth crustal elements such as Al, Si, K, Na were more easily enriched at the height of 1.5 m, while anthropogenic pollution elements such as Cr,Ni,Cu,Zn,As and Pb were easily enriched at 2.5 m height. Source analysis showed that pollution of road dust fall PM_2.5 from Shijiazhuang during heating season were compounded by coal, fuel, traffic (vehicle parts aging wear and exhaust emissions, tire wear, road dust), building dust and biomass combustion. The enrichment factors varied from 0.35 to 100.45. Crust elements were not enriched. Among all elements, Cr had the highest average enrichment factor of 100, and the ecological risk index of 320, which should be caught much more attention.