城市路面径流污染负荷及采样次数对其估算准确性的影响  

Pollution Load of Urban Road Runoff and Impact of Sampling Frequency on It's Estimation Accuracy

作　　者：陈莹[1] 赵剑强[1] 胡博[1] 刘珺[1] 毛鹤群[1] 

机构地区：[1]长安大学环境科学与工程学院,西安710054

出　　处：《城市环境与城市生态》2011年第3期9-14,共6页Urban Environment & Urban Ecology

基　　金：中央高校基本科研业务费专项资金资助项目(CHD2009JC118);长安大学基础研究支持计划资助项目

摘　　要：在西安市城市主干道南二环路建立路面径流原位采样站,利用自制流量等比例采样装置,采集2009年3月—2010年2月的36场降雨径流,测试各场次径流SS、COD、溶解性COD、NH4-N、Pb、Zn和溶解态Pb、Zn的事件平均浓度(EMC),计算径流年污染负荷,并采用随机抽样方法研究采样次数对污染负荷估算准确性的影响。结果表明,西安市城市主干道径流EMC的宽幅变化导致各场次径流污染负荷变异大,每年每公顷城市主干道路由路面径流向受纳水体排放的SS、COD、溶解态COD、NH4-N、Pb、Zn和溶解态Zn负荷分别为11 090.29 kg、3 462.50 kg、812.48 kg、13.49 kg、0.28 kg、1.35 kg和0.59 kg,具有较大的污染潜力;由于路面径流EMC的宽幅变异性,当实测径流场次较少时,其EMC平均值不能准确表征路面径流污染的统计特征,用其代表地点平均浓度(SMC)计算年污染负荷误差较大;随机抽样结果表明,当采样径流场次大于16场时,路面径流各污染指标随机抽样样本EMC均值与SMC的最大相对误差均小于30%,也即,若能保证至少实测16场降雨径流,以各场次径流EMC实测结果均值作为SMC计算的径流年污染负荷的最大相对误差在30%以内。Samples from urban trunk road runoff caused by 36 storm events were collected proportionally to the total volume at south second ring road in Xi＇an City using self-made volume proportional collecting device from Mar.2009 to Feb.2010.Event mean concentrations（EMC） of SS,COD,dissolved COD,NH4-N,Pb,Zn and dissolved Zn were tested and the annual pollution loads of each pollutant were calculated.Random sampling method was used to investigate the impact of sampling frequency on estimation accuracy of road runoff pollution load.The results showed that the pollution load of urban trunk road runoff in Xi＇an City was quite different between various storm events as EMC of road runoff vary widely.The annual pollution loads of SS,COD,dissolved COD,NH4-N,Pb,Zn and dissolved Zn were 11 090.29 kg/（hm2·a）,3 462.50 kg/（hm2·a）,812.48 kg/（hm2·a）,13.49 kg/（hm2·a）,0.28 kg/（hm2·a）,1.35 kg/（hm2·a）and 0.59 kg/（hm2·a） respectively,which indicated that urban road runoff had a rather high polution potential.The average EMC could not represent the statistical characteristics of road runoff pollution accurately when the sampling size was not big enough.The error of calculated annual pollution load would be quite big if SMC was represented by the average EMC of the small samples.When sampling frequency was more than 16,the maximum relative error between SMC with average EMC was below 30%.That is to say,if at least 16 runoff events were sampled and monitored,the average EMC of those runoff events could represent the SMC with rather high accuracy and the maximum relative error of calculated annual pollution load was below 30%.

关 键 词：路面径流 污染负荷 采样次数 事件平均浓度 地点平均浓度 随机抽样 误差 

分 类 号：X52[环境科学与工程—环境工程]