Characteristics of Washed-off Pollutants from Railway Station During Storms

The ministry of Environment, Korea, are designing the TMDL(Total Maximum daily Load) program far 4 major large rivers to improve water quality from possible pollutants. It can be successfully performed as controling of nonpoint pollutants from watershed area. Railway stations are stormwater intensive land use because of high imperviousness and high pollutant mass emissions from various activities. Especially the metal pollutants from the railway station were recognized as an important pollutants because of its toxicities. In order to characterize the washed-off pollutants. the monitoring were performed on a railway station during storms. Pollutant concentrations are exponentially decreasing during the storm duration. The 95％ confidence interval of pollutant concentrations in an hour storm duration ranges from 61.6 to 115.4mg/L for TSS(mean=88.50mg/L),103.8-244.1mg/L for COD(mean=174 mg/L) and 7.68-17.32mg/L for Oil & Grease(mean=12.5mg/L). The ranges of metals were 39.2-84.0 /L for total Cu(mean=61.6/L), 14.0-25.8/L for total Pb(mean=19.9/L) and 182.2-376.l /L for total Zn(mean=279.2/L). The first flush criteria for best management practices can be suggested to 50％ pollutant mass emissions during 30％ of the total flow.