The characteristics of expressway runoff quality and pollutants discharge rule.

With on-site continuous sampling, drainage water from expressway runoff of Xi'an-Lintong expressway was monitored in a period of a wet weather. The results show that the expressway runoff has greater pollution intensity and the main pollutants are SS and COD with rather low biodegradability. There are better linear relations among the waterquality parameter SS, COD, total Pb and total Zn. The rule of pollutant discharge of the highway runoff and its impact on water quality of the river were discussed.