Characteristics of pollutants in urban rainfall runoff in Shenyang City

Rainfall runoff,the main driving force of pollutant migration,is the hotspot of urban non-point source pollution researches. Shenyang,a typical city of northeast China,was chosen as a case study. Discharge characteristics of ten main pollutants( TSS,TN,TP,COD,Cd,Pb,Cr,Cu,Ni and Zn) were analyzed in different underlying surfaces,including slope roof runoff,flat roof runoff and road runoff. The study demonstrated that pollutant concentration peaks were earlier than runoff peaks. The pollution level was more serious in the road runoff than in the roof runoff. TN was the main pollutant in the roof runoff. However,TSS,TN,TP,Pb and Cr were main pollutants of the road runoff. The concentrations of all pollutants exceed the V level of China's national surface water quality standards. There was a correlation between TSS and other 8pollutants in the runoff except TN. Nutrition elements( nitrogen and phosphorus) had strong positive correlations with precipitation and rainfall intensity. COD discharged gradually along with the duration of rainfall. Comparing the research with other countries or cities,we found that the pollution of TSS,TN,TP and COD in Shenyang roof runoff was lighter; however,there was heavy metal pollution. The concentrations of TSS,TP and some heavy metal pollutions( Pb,Cr,Cu and Zn) in the road runoff were very high,but the TN and COD concentrations were low.