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----a,lusGs <br /> science for a changing world <br /> Coal-Tar-Based Pavement Sealcoat, Polycyclic Aromatic <br /> Hydrocarbons (PAHs), and Environmental Health <br /> Studies by the U.S. Geological Survey(USGS)have identified coal-tar-based sealcoat—the black, viscous <br /> liquid sprayed or painted on asphalt pavement such as parking lots—as a major source of polycyclic aromatic <br /> hydrocarbon (PAH)contamination in urban areas for large parts of the Nation. Several PAHs are suspected <br /> human carcinogens and are toxic to aquatic life. <br /> xt <br /> CRY, <br /> Sealcoat is the black,viscous liquid sprayed or painted on the asphalt pavement of many parking lots,driveways,and playgrounds. <br /> Key Findings <br /> • Dust from pavement with coal-tar-based sealcoat has greatly elevated PAH concentrations compared to <br /> dust from unsealed pavement. <br /> • Coal-tar-based sealcoat is the largest source of PAH contamination to 40 urban lakes studied, accounting <br /> for one-half of all PAH inputs. . <br /> • Coal-tar-based sealcoat use is the primary cause of upward trends in PAHs, since the 1960s, in urban lake <br /> sediment. <br /> • Residences adjacent to parking lots with coal-tar-based sealcoat have PAH concentrations in house dust <br /> that are 25 times higher than those in house dust in residences adjacent to parking lots without coal-tar- <br /> based sealcoat. <br /> • PAHs move from a sealcoated surface into our environment by many mechanisms: storm runoff, adhesion <br /> to tires, wind, foot traffic, and volatilization. <br /> Volatilization <br /> Adhesion <br /> t <br /> e„ .r► <br /> 9 <br /> Tracking ,,/ <br /> .• al?' ...:... . <br /> n <br /> ..., . , , , <br /> 00: <br /> Wind <br /> Sealant <br /> Asphalt <br /> Original graphic courtesy of Aaron Hicks,City of Austin,Texas. Runoff <br /> U.S.Department of the Interior .. Fact Sheet 2011-3010 <br /> U.S.Geological Survey �: Printed on recycled paper February 2011 <br />