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Handout for PAH Seminar 12/9/10 <br />Contents <br />1. USGS Web page excerpts PAHs Coal- Tar -Based Pavement Sealcoat <br />2. MPCA Coal Tar -based Sealcoat: Environmental Concerns <br />3. USEPA Fact Sheet Polycyclic Aromatic Hydrocarbons <br />4. USGS Report: Parking Lot Sealcoat <br />USGS Web page <br />Handout printing courtesy of r <br />MAnesoua Chief <br />bICRI•a1Pt <br />Coa boon <br />4 Bonestroo <br />PAHs and Coal- Tar -Based Pavement Sealcoat <br />Polycyclic aromatic hydrocarbons, or PAHs, are a group of organic compounds <br />composed of fused benzene rings. PAHs occur naturally in crude oil, coal, and <br />tar, and are produced by the incomplete combustion of fossil fuels and biomass <br />(wood, grass, tobacco). They are widely distributed in the environment and are <br />of concern because they are toxic, mutagenic, teratogenic, and several are <br />probable human carcinogens. <br />Pavement sealcoat (also called sealant) is a black liquid that is sprayed or <br />painted on asphalt parking lots and driveways. It is marketed as protecting and <br />beautifying the asphalt pavement. Sealcoat is used commercially and by <br />homeowners across the Nation. It is applied to residential driveways, <br />playgrounds, and parking lots associated with commercial businesses, <br />apartment and condominium complexes, churches, schools, and business parks. <br />Most sealcoat products have a coal tar -pitch or asphalt base. Coal- tar -based <br />sealcoat is commonly used in the central, southern, and eastern U.S., and <br />asphalt -based sealcoat is commonly used in the western U.S. <br />Coal -tar pitch can contain 50 percent or more PAHs by weight and is known to <br />cause cancer in humans (International Agency for Research on Cancer, 1985). <br />Coal -tar -based sealcoat products typically are 20 to 35 percent coal -tar pitch. <br />Product analyses indicate that coal- tar -based sealcoat products contain about <br />1,000 times more PAHs than sealcoat products with an asphalt base (City of <br />Austin, 2005). <br />Key Findings from USGS Studies <br />Dust from pavement with coal- tar -based sealcoat has PAH concentrations <br />hundreds to thousands of times higher than dust from pavement with no <br />sealcoat or with asphalt based sealcoatl,2. <br />9//a it 0 R G 14 <br />C./ 4f fv i r' it`s r <br />