State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, People's Republic of China.
Environ Sci Pollut Res Int. 2018 Jan;25(3):2377-2388. doi: 10.1007/s11356-017-0576-z. Epub 2017 Nov 9.
As a climate-driven event, nonpoint source (NPS) pollution is caused by rainfall- or snowmelt-runoff processes; however, few studies have compared the characteristics and mechanisms of these two kinds of NPS processes. In this study, three factors relating to urban NPS, including surface dust, snowmelt, and rainfall-runoff processes, were analyzed comprehensively by both field sampling and laboratory experiments. The seasonal variation and leaching characteristics of pollutants in surface dust were explored, and the runoff quality of snowmelt NPS and rainfall NPS were compared. The results indicated that dusts are the main sources of urban NPS and more pollutants are deposited in dust samples during winter and spring. However, pollutants in surface dust showed a low leaching ratio, which indicated most NPS pollutants would be carried as particulate forms. Compared to surface layer, underlying snow contained higher chemical oxygen demand, total suspended solids (TSS), Cu, Fe, Mn, and Pb concentrations, while the event mean concentration of most pollutants in snowmelt tended to be higher in roads. Moreover, the TSS and heavy metal content of snowmelt NPS was always higher than those of rainfall NPS, which indicated the importance of controlling snowmelt pollution for effective water quality management.
作为一种由气候驱动的事件，非点源（NPS）污染是由降雨或融雪径流过程引起的；然而，很少有研究比较这两种 NPS 过程的特征和机制。在本研究中，通过现场采样和实验室实验综合分析了与城市 NPS 相关的三个因素，包括地表灰尘、融雪和降雨径流过程。探讨了地表灰尘中污染物的季节性变化和浸出特性，并比较了融雪 NPS 和降雨 NPS 的径流质量。结果表明，灰尘是城市 NPS 的主要来源，冬季和春季灰尘样品中沉积了更多的污染物。然而，地表灰尘中的污染物浸出率较低，表明大部分 NPS 污染物将以颗粒形式被携带。与表层相比，底层雪中含有更高的化学需氧量、总悬浮固体（TSS）、Cu、Fe、Mn 和 Pb 浓度，而融雪过程中大多数污染物的事件平均浓度在道路上往往更高。此外，融雪 NPS 的 TSS 和重金属含量始终高于降雨 NPS，这表明控制融雪污染对于有效水质管理非常重要。
