深圳大气湿沉降对典型屋面径流水质的影响

Study on Water Quality of Roof-Runoff Affected by Atmospheric Wet Deposition in Shenzhen

屋面雨水是一种重要的非常规水源,其水质受大气湿沉降影响。该研究以深圳大学城水泥砂浆材质的屋面为例,测定了2011年14场降雨的雨前大气环境质量、大气降水水质和屋面径流水质,对比了大气降水及屋面径流中组分浓度的差异,分析了湿沉降与屋面径流污染负荷的关系及其影响因素。结果表明:(1)湿沉降中NH4+、乙酸、甲酸和乙二酸等组分与屋面材料及累积物发生化学反应,使得这些组分在屋面径流中的负荷显著减少;(2)湿沉降是屋面径流中Na+、K+、Mg2+、Ca2+和SO42-组分负荷的少部分来源;(3)而湿沉降是屋面径流中TOC、F-和NO3-组分负荷的主要来源;(4)雨前大气环境质量对湿沉降组分浓度有显著影响。因此,湿沉降对屋面径流组分负荷影响显著,城市屋面径流水质管理中应充分考虑湿沉降的影响。

Rainwater as a kind of water resources was studied in Shenzhen with respect to its water quality, in which influences of atmospheric wet deposition were taken into account. With the data, collected during 14 rainfall events in 2011, of the air quality before raining, of the rainwater quality and of the roof runoff water quality, effects of wet deposition on the pollution loads of roof runoff water were analyzed. According to the analysis, pollutants such as TOC, F- and NO^3- in runoff mostly came from the wet deposition. The findings also revealed that some chemical reactions took place between the chemicals contained in wet deposition, e.g, NI-^4＋, acetic acid, formic acid and oxalic acid, and the materials of the roof as well as the matter retained on the roof, and that quality of atmospheric air greatly affected the wet deposition in terms of the content of its components.