街尘污染物在典型城市下垫面的可迁移势及滞尘机理研究

Road-deposited sediments (RDS) are ubiquitous carriers of urban diffuse pollutants. It discharges rapidly during rainfall-runoff process, causing the first flush with high pollution load. A right risk assessment for contaminants associated with RDS is crucial for urban diffuse pollution control. In this project, the characteristics of the typical urban surface types (impervious surfaces including asphalt, concrete and mainly brick paving surfaces) and the corresponding retained RDS will be investigated. The long term field study at the selected sites and simulation experiments will be applied to analyze the influence of urban surface characteristics and physical and chemical properties of RDS on the build-up and wash-off process of RDS. The key factors to affect the RDS mobility will be determined and they are associated with properties of both RDS and urban surfaces from the indoor simulation and on-site detection. The theory of the RDS mobility potential will studied and a model based on it will be the goal of study. Furthermore, The RDS mobility potential will be verified and calibrated by RDS washoff pollution by indoor and on-site experiments. The RDS mobility potential theory and model will be tested in an urban region to assess pollution in RDS at regional scale.

街尘是城市面源污染物分布最广泛的载体，它在降雨过程的集中泄流是引起径流初期污染高负荷的重要原因，正确评估街尘及其负载污染物迁移过程对于预测城市面源污染风险和对其的有效控制有着重要意义。本研究拟在阐明典型下垫面（不透水路面以沥青、混凝土为主和铺装路面以方砖为主）及其滞留街尘自相似性的基础上进行类型划分，揭示典型下垫面特征及其所滞留街尘特征的关联性，然后利用长期野外定位试验与人工控制模拟试验，研究下垫面特征与街尘理化性质对街尘长期累积和降雨时随径流释放的影响规律，确定影响其可迁移性的若干下垫面参数和街尘理化性质，创建单位面积不同城市下垫面上街尘污染物的可迁移状态标准化定量表征，建立街尘可迁移势理论与模型，最后利用天然和人工降雨情景下的地表径流污染对街尘可迁移势进行验证与校准。可迁移势的相关理论和模型将被用来评价区域尺度上街尘引起的城市面源水污染。

街尘降雨径流冲刷是城市面源颗粒污染物的重要来源，是城市地表径流污染控制和处理的重要目标。本研究从微观街尘与城市下垫面相互作用的角度，以典型沥青和水泥路面为例，分析了不同降雨特征下路面粗糙度、颗粒物粒径大小等对街尘可迁移性的影响，量化揭示了街尘在下垫面上的滞留机理。在地块汇水区尺度上，构建了基于透水/不透水斑块格局与城市地表径流污染过程耦合效应的产流产污表征的模型方法。该模型方法对如何利用城市透水下垫面（绿地）生态滞尘提供了方法学，为我国城市面源颗粒物污染的源头控制提供重要依据。