Abstract:

In recent years，as the rapid extension and development of expressway in China，numerous environmental issues sprout up，among which nonpoint source pollution of runoff appears seriously.With the methods of onsite continuous sampling and the national standard water quality analysis，monitoring of the surface runoff has been carried out in Chongqing Yuwu Expressway.The research analysed the flow trend of the surface runoff，calculated the Event Mean Concentration (EMC) and explored the correlation between the pollution factors and biodegradability.The results showed that the initial effect was significant among rainfall events with large rainfall at the initial stage.The EMC demonstrated that the great majority of pollutant concentrations exceeded V type of Surface Water Standards and II Emission Standards.High concentrations of SS，COD，TN，TP，being the main pollutants，contributed to the pollution to a larger extent.It existed fine linear correlation among the water quality parameters：SS，COD，BOD5，TP，Cu，Zn，and Pb.The poor biodegradability proved that the traditional biological treatment method was not a suitable processing approach of this kind of runoff.This study could provide a  reference for further research on the pollution of Chongqing′s runoff，and scientific basis for the control and management of the Environmental Protection Department.〖