昆明主城区城市地表径流污染特征分析

昆明市位于滇池上游,城市地表径流污染负荷对滇池水质具有直接影响。通过对昆明主城区内不同功能区12个监测点7次降雨径流过程水样的采集与分析,研究了昆明主城区城市地表径流污染特征。结果表明,昆明主城区城市地表径流中TSS、COD、TN和TP的多场降雨平均浓度分别为182.8、138.2、2.37和0.43 mg/L。不同功能区的地表径流水质存在显著差异(p<0.05);各功能区径流污染负荷顺序为:公路区>商业区>住宅区>文教区;不同功能区单场降雨径流水质动态变化规律是:污染物浓度在降雨径流初期相对较高,中后期浓度快速下降,并逐渐趋于稳定;地表利用功能、降雨特征和交通流量是影响城市地表径流水质的主要因素;城市地表径流中COD、TN、TP与TSS之间有较好的相关性,说明大部分的污染物质是以颗粒吸附态存在。

Characterization of urban surface runoff in main districts of Kunming

Located on upstream of Dianchi Lake, the pollution load of urban surface runoff in Kunming contributes greatly to the water quality of Dianchi Lake. In this study, runoff samples were collected from 12 monitoring sites in Kunming city during seven rain events in order to characterise urban surface runoff. The results showed that the average values for TSS, COD, TN and TP of urban surface runoff were 182.8 mg/L, 138.2 mg/L, 2.37 mg/L and 0.43 mg/L, respectively. There was significant difference in urban surface runoff among four functional areas. The pollution load followed the order of road areas> commercial areas> residential areas> cultural and educational areas. During a single rainfall event, pollutant concentration was higher at beginning, and decreased quickly to a relative stable level. Land use function, rainfall characteristics, and traffic volume were the main factors determining urban surface runoff quality. The TSS was significantly correlated with COD, TN, and TP, indicating that most pollutants were absorbed on the particle surface.