Analysis of non-point source characteristics of heavy metals and oil and grease at railway bridge area with various land uses

摘要

Many studies have been conducted on the topic of non-point source management in various land-use areas to suggest non-point source management methods. However, the non-point source research pertaining to railway facilities is incomplete. In this study, six instances of rainfall monitoring were accomplished in a target railway bridge area on heavy metals (cadmium (Cd), copper (Cu), and lead (Pb)) and oil and greases (O&G). Based on the monitored data, heavy metals and O&G run-off characteristics, the event mean concentration (EMC) data, and pollutant load per unit area were analyzed. The concrete road-bed area run-off showed the characteristic first flush effect. The gravel road-bed area run-off characteristic showed the first flush effect or showed two-peaks. The EMC data showed higher values for the concrete road-bed area than for the gravel road-bed area. Heavy metals and O&G pollutant load per unit area in a railway bridge area showed higher values than those of pavement and urban areas. These results indicate that a considerable amount of heavy metals and O&G mass occur during rainfall events, indicating the need to manage non-point sources pollution in railway bridge areas.