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The study revealed that the asphalt -based sealcoat runoff <br />contained 10 times more PAH than the uncoated parking <br />lot and the coal-tar sealcoat runoff had concentrations of <br />PAH that were 65 times higher than the uncoated lot. <br />Maintenance expenses <br />Besides the health effects and the danger to the <br />environment, PAHs are making routine maintenance of <br />stormwater ponds by cities and townships many, many <br />times more expensive because sediment with high <br />enough concentrations of PAHs must be disposed of <br />differently. <br />In Minnesota, when some cities removed sediment from <br />their storrnwater ponds as part of regular maintenance, <br />they found elevated levels of PAHs. This discovery <br />required them to fmd special disposal areas, costing <br />them many thousands of dollars more. <br />Current regulation <br />Because of the environmental problems associated with <br />PAHs, the City of Austin, Texas, Dane County, <br />Wisconsin, and Washington D.C. have banned use of <br />coal tar -based sealcoat in their jurisdictions (asphalt <br />based sealcoat may still be used). <br />Recent legislation passed in Minnesota bans the <br />purchase of coal -tar sealcoat products by state agencies <br />by July 1, 2010. Recently, two national home- <br />Coal- tar -based Driveway Sealcoat wq- strm4 -12 September 2009 <br />page 2 <br />improvement retailers, Lowe's and Home Depot, took <br />coal tar -based sealcoat off their shelves. Check with your <br />local unit of government to see if there are any <br />restrictions. <br />Make the right choice <br />The best choice may be to not sealcoat your driveway at <br />all. But if you do choose to sealcoat, study labels <br />carefully to be sure to find an asphalt -based product. <br />Lower concentrations of PAHs in waterways will <br />prevent costly maintenance for your city and keep <br />waterways safe for fish and other aquatic organisms. <br />If you have leftover material after sealing your <br />driveway, you can re -use or recycle it at your <br />community's household hazardous waste facility. To <br />fmd your local facility, <br />visit: www.pca.state.mn.us/waste/hhw <br />References <br />Van Metre, P.C., Mahler, B.J., Scoggins, M., and <br />Hamilton, P.A., 2006. Parking Lot Sealcoat: A <br />Major Source of Polycyclic Aromatic Hydrocarbons <br />(PAHs) in Urban and Suburban Environments. A <br />USGS report prepared in cooperation with the City <br />of Austin, Texas. <br />Minnesota Pollution <br />tE Cranial Agency <br />