title: A comparative study of the grain-size distribution of surface dust and stormwater runoff quality on typical urban roads and roofs in Beijing, China.
abstract: The deposition of pollutants on impervious surfaces is a serious problem associated with rapid urbanization, which results in non-point-source pollution. Characterizing the build-up and wash-off processes of pollutants in urban catchments is essential for urban planners. In this paper, the spatial variation and particle-size distributions of five heavy metals and two nutrients in surface dust were analyzed, and the runoff water first-flush effect (FF30) and event-mean concentrations (EMCs) of 10 common constituents were characterized. The relationships between runoff variables and stormwater characteristics were examined from three typical urban impervious surfaces in Beijing, China. Dust on road surfaces with smaller grain sizes had higher pollutant concentrations, whereas concentrations of Mn, Zn, Fe, and TP in roof surface dust increased with grain size. Particles with grain sizes of 38-74 and 125-300 μm contributed most to the total pollutant load in roads, while particles with the smallest grain sizes (<38 μm) contributed most on roofs (23.46-41.71 %). Event-mean concentrations (EMCs) and FF30 values for most runoff pollutants tended to be higher on roofs than on roads. The maximum intensity (I max) and the antecedent dry days (ADD) were critical parameters for EMCs in roads, while ADD was the only dominant parameter for EMCs on our studied roof. The rainfall intensity (RI) and maximum intensity (I max) were found to be the parameters with the strongest correlation to the first-flush effect on both roads and roofs. Significant correlations of total suspended solids (TSS) concentration in runoff with grain-size fractions of surface dust indicated that coarser particles (74-300 μm) are most likely to contribute to the solid-phase pollutants, and finer particles (<38 μm) are likely the main source of dissolved pollutants.
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, People's Republic of China. zyshen@bnu.edu.cn.
authors.forename: Zhenyao
authors.initials: Z
authors.lastname: Shen
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, People's Republic of China.
authors.forename: Jin
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, People's Republic of China.
authors.forename: Guzhanuer
authors.initials: G
authors.lastname: Aini
authors.affiliation: Key Laboratory of Urban Stormwater System and Water Environment, Beijing University of Civil Engineering and Architecture, Beijing, 100044, People's Republic of China.
authors.forename: Yongwei
authors.initials: Y
authors.lastname: Gong
mesh_terms: D000068476:Beijing; D002681:China; D004391:Dust; D004784:Environmental Monitoring / Q000379:methods; D004787:Environmental Pollution; D006798:Housing; D019216:Metals, Heavy; D010316:Particle Size; D011891:Rain; D014507:Urbanization; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D004391:Dust; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical
keywords: Event mean concentration; First-flush effect; Grain-size distribution; Nonpoint source pollution; Urban runoff