Assessment of Water Quality of Runoff from Sealed Asphalt Surfaces

This report discusses the results of runoff tests from recently sealed asphalt surfaces conducted at the U.S. Environmental Protection Agency's (EPA) Urban Watershed Research Facility (UWRF) in Edison, New Jersey. Both bench-scale panels and full-scale test plots were evaluated. Full-scale tests were performed on an asphalt portion of the UWRF parking lot; no parking was allowed on any of the surfaces to minimize cross-contamination from other sources. A variety of water quality analyses of the runoff were conducted. The whole water sample was analyzed rather than analyzing the particle and dissolved phases separately. The primary measurement was polycyclic aromatic hydrocarbons (PAHs). Sealants applied to asphalt surfaces leached measurable quantities of PAHs. Results indicated that the time from the initial sealant application is a major factor in observed PAH concentration in runoff. The highest PAH concentrations measured were in initial runoff samples where sampling was performed twenty-four hours after application of sealants to the asphalt surface. Toxicity screening assays produced inconclusive data due to matrix effects of prepared samples.