Abstract
Nonpoint pollutants were monitored on railway station land use. Lots of pollutant mass were washed-off in a first hour. The 95$\%$ confidence interval of pollutant concentrations ranges from 61.6 to 115.4 mg/L for TSS(mean= 88.50 mg/L). 103.8$\∼$244.1 mg/L for COD(mean= 174 mg/L) and 7.68$\∼$17.32 mg/L for Oil & Grease(mean= 12.5 mg/L). The various metals were also washed-off during storm runoff from railway station. The ranges of 95$\%$ confidence intervals were 39.2$\∼$84.0 ug/L for total Cu(mean= 61.6 ug/L), 14.0 $\∼$ 25.8 ug/L for total Pb(mean= 19.9 ug/L) and 182.2 $\∼$ 376.1 ug/L for total Zn(mean= 279.2 ug/L). As a result of this research, we concluded that up to 50$\%$ of the total pollutant mass can be removed when first 30$\%$ of the total flow are treating, and it can be a first flush criteria for best management practices.
