城市地表灰尘重金属研究进展及展望

城市地表灰尘是城市环境科学研究的对象之一,在对国内外有关城市灰尘概念界定研究成果进行总结的基础上,对城市地表灰尘提出新的概念和新的认识。城市地表灰尘是城市生态环境中具有环境指示作用的地表颗粒物,是含有重金属、多环芳烃等多种污染物的源与汇。对国内外地表灰尘重金属的含量水平、时空分布特征、迁移循环、赋存形态及生物有效性等方面的研究成果进行比较系统的阐述;灰尘中重金属的来源识别的方法主要有GIS空间分析,元素示踪技术,统计学方法等。并提出在今后的研究中应进一步完善城市地表灰尘中重金属的时间变化规律、地表灰尘在环境中的滞留时间、粒径的划分以及区域人体健康影响及风险评估模型优化四个方面的研究。

The advances in research on heavy metals of the surface dust in urban areas

Surface dust in urban areas is one of the important topics in urban environmental science.A review was given in this paper on the conceptual definition of surface dust in urban areas.The new concept and new understandings about surface dust in urban areas were put forward.Surface dust was sources and sinks of many pollutants as heavy metals and PAHs have environmental indicative function in urban areas.A review was given on the advances in the research on heavy metals of surface dust in urban areas in various aspects in this paper,such as content level,space-time distribution,transference and cycle,forms and bioavailability.The concentrations of heavy metals of surface dust in surface dust in urban areas were obviously higher than environmental background values in soil.The research on methods of spatial distribution of heavy metals were line type and face type.The concentrations of pollutants have changed over times.The main transporting medium of surface dust is atmosphere.The heavy metals in surface dust has exchangeable,carbonate combination,iron and manganese oxide combination,organic sulfide combination patterns and residua.The main sources of heavy metals in surface dust were traffic pollution,industrial pollution and urban construction.The sources identification methods included GIS spatial analysis,element tracer technology and multivariate analysis.The future development prospects were also pointed out.It is an urgent task to study the temporal variations such as diurnal changes,seasonal changes or non-seasonal changes by any factors control,the residence time in environment,particle classification as well as to establish standards and study the relationship between transfer characteristics and particle sizes,to optimize the regional human health effects and risk assessment model such as confirming the main routes of exposure,optimizing exposure calculation model and carrying out the human body health risk assessment.