Wang Zhenyu, Hua Pei, Dai Heng, Li Rui, Xi Beidou, Gui Dongwei, Zhang Jin, Krebs Peter
Institute of Urban Water Management, Technische Universität Dresden, 01062, Dresden, Germany.
The Environmental Research Institute, MOE Key Laboratory of Environmental Theoretical Chemistry, South China Normal University, 510006, Guangzhou, China.
Environ Sci Ecotechnol. 2020 Feb 8;2:100017. doi: 10.1016/j.ese.2020.100017. eCollection 2020 Apr.
Particulate-associated trace metals have been regarded as an important pollution source for urban surface runoff. Cd, Pb, Cu, Zn and total solids (TS) washed off two different surfaces (low-elevated facade and road surfaces) under two kinds of antecedent environmental conditions (dry and snow-melting) were determined in this study. Wet-vacuuming sweeping (WVS) and surface washing (SW) methods, representing the maximum pollution potential and common rainfall-induced wash-off condition respectively, were used to collect the particulate matters. The result shows that the wash-off concentrations of trace metals were found in the order of Cd (2.28 ± 2.08 μg/l) < Pb (435.85 ± 412.61 μg/l) < Cu (0.93 ± 0.61 mg/l) < Zn (2.52 ± 2.30 mg/l). The snow-melting process had a considerable influence on the wash-off concentrations of the trace metals on both road and facade surfaces. It reduced >38% and >79% of metals and TS concentrations in the facade surface and road surface runoff respectively. The wash-off concentrations of Cd, Cu, and Zn on the road surface 45-780% higher than those on the facade surfaces. The sensitivity analysis based on the Bayesian network indicates that the wash-off concentrations of metals were mainly dependent on the antecedent environmental conditions or the surface properties while the sampling methods had a minor influence. Therefore, to accurately model the pollutant migration in the surface runoff requires an improving method considering different surfaces and antecedent environment conditions.
颗粒态痕量金属被视为城市地表径流的重要污染源。本研究测定了在两种前期环境条件（干燥和融雪）下，从两种不同表面（低立面和路面）冲刷下来的镉（Cd）、铅（Pb）、铜（Cu）、锌（Zn）和总固体（TS）。分别采用代表最大污染潜力的湿真空清扫（WVS）法和代表常见降雨冲刷条件的表面冲洗（SW）法收集颗粒物。结果表明，痕量金属的冲刷浓度顺序为：镉（2.28±2.08μg/l）＜铅（435.85±412.61μg/l）＜铜（0.93±0.61mg/l）＜锌（2.52±2.30mg/l）。融雪过程对路面和立面表面痕量金属的冲刷浓度有相当大的影响。它分别使立面表面和路面径流中的金属和TS浓度降低了>38%和>79%。路面上镉、铜和锌的冲刷浓度比立面表面高45 - 780%。基于贝叶斯网络的敏感性分析表明，金属的冲刷浓度主要取决于前期环境条件或表面性质，而采样方法的影响较小。因此，要准确模拟地表径流中的污染物迁移，需要一种考虑不同表面和前期环境条件的改进方法。
