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Coal -tar pitch from sealcoat reaches streams and lakes in runoff and soils and <br />unsealed pavement near sealed parking Iots3. <br />Coal- tar -based sealcoat was determined to be the largest source of PAH <br />contamination to urban lakes4. <br />Use of coal -tar based sealcoat is the primary cause of upward trends in PAHs in <br />urban lake sediment4,5. <br />Residences adjacent to parking lots with coal tar -based sealcoat have house dust <br />with elevated concentrations of PAHs6. <br />Frequently Asked Questions about sealcoat, coal tar, and PAHs <br />What are sealcoat, coal tar, and PAHs? <br />Pavement sealcoat, or sealant, is a black liquid that is sprayed or painted on asphalt <br />pavement. It is marketed as protecting and beautifying the asphalt surface. Sealcoat is <br />used commercially and by homeowners across the Nation. It is applied to residential <br />driveways, playground, and parking lots associated with commercial businesses, <br />apartment and condominium complexes, churches, schools, and business parks. Most <br />sealcoat products have a coal tar -pitch or asphalt base. Coal- tar -based sealcoat is most <br />commonly used in the central, southern, and eastern U.S., and asphalt -based sealcoat is <br />used predominantly in the western U.S. <br />Coal tar is a byproduct of the coking of coal, and can contain 50 percent or more PAHs <br />by weight. Coal -tar pitch is known to cause cancer in humans (International Agency for <br />Research on Cancer, 1985). Coal- tar -based sealcoat products typically are 20 to 35 <br />percent coal -tar pitch. Product analyses indicate that coal- tar -based sealcoat products <br />contain about 1,000 times more PAHs than sealcoat products with an asphalt base (City <br />of Austin, 2005). <br />Polycyclic aromatic hydrocarbons (PAHs) are a group of chemical compounds that form <br />during the combustion of anything with a carbon base, from wood and gasoline to <br />cigarettes and meat. PAHs also are found in products whose production involves the <br />heating of hydrocarbons, such as automobile tires and coal -tar pitch. PAHs are of <br />environmental concern because several are toxic, carcinogenic, mutagenic, and(or) <br />teratogenic (causing birth defects) to aquatic life and because several are probable <br />human carcinogens. <br />How does sealcoat get from driveways and parking lots into streams and <br />lakes? <br />Friction from vehicle tires abrades pavement sealcoat into small particles. These small <br />particles are washed off pavement by precipitation and into storm drains and streams. <br />Wear and tear of sealcoat is visible in high traffic areas within a few months after <br />