Control Approach to Non-biodegradable Organic Matter in Roadway Runoff

Roadway dust includes non-biodegradable and hazardous organic pollutants such as polycyclic aromatic hydrocarbons (PAHs). The objective of this study was to estimate the proportion of non-biodegradable organic matter (NBOM) in roadway runoff using a biodegradability test, and to reveal the effectiveness of its removal using soil infiltration. Total organic carbon (TOC) concentration of roadway runoff was approximately 20 mg/L and its 74% was estimated to be NBOM. The percentage of NBOM in particulate organic carbon (POC) reached 96%, which was much higher than that in dissolved organic carbon (DOC, 40%). Although 5 polycyclic aromatic hydrocarbons were detected in roadway runoff, they were removed by the aerobic biodegradation for 100 days incubation. The soil infiltration was able to reduce NBOM in roadway runoff by 93% in POC and 55% in DOC, whereas the removal efficiencies of biodegradable organic matter in POC and DOC were only 25% and 59%, respectively. Consequently, the soil infiltration is thought to be a potential measure to reduce NBOM loads to water environment through roadway runoff.