title: Grain size distribution of road-deposited sediment and its contribution to heavy metal pollution in urban runoff in Beijing, China.
abstract: Pollutant washoff from road-deposited sediment (RDS) is an increasing problem associated with the rapid urbanization of China that results in urban non-point source pollution. Here, we analyzed the RDS grain size distribution and its potential impact on heavy metal pollution in urban runoff from impervious surfaces of urban villages, colleges and residences, and main traffic roads in the Haidian District, Beijing, China. RDS with smaller grain size had a higher metal concentration. Specifically, particles with the smallest grain size (<44 μm) had the highest metal concentration in most areas (unit: mg/kg): Cd 0.28-1.31, Cr 57.9-154, Cu 68.1-142, Ni 25.8-78.0, Pb 73.1-222 and Zn 264-664. Particles with smaller grain size (<250 μm) contributed more than 80% of the total metal loads in RDS washoff, while suspended solids with a grain size <44 μm in runoff water accounted for greater than 70% of the metal mass in the total suspended solids (TSS). The heavy metal content in the TSS was 2.21-6.52% of that in the RDS. These findings will facilitate our understanding of the importance of RDS grain size distribution in heavy metal pollution caused by urban storm runoff.
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Beijing 100085, China.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Zhao
authors.forename: Xuyong
authors.initials: X
authors.lastname: Li
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Wang
authors.forename: Di
authors.initials: D
authors.lastname: Tian
mesh_terms: D002681:China; D004787:Environmental Pollution; D019216:Metals, Heavy / Q000032:analysis*; D018986:Motor Vehicles; D010316:Particle Size; D011891:Rain; D001335:Vehicle Emissions / Q000032:analysis*; D014872:Water Movements
chemical_list: D019216:Metals, Heavy; D001335:Vehicle Emissions