2010-10-26_PWETC_AgendaPacket - Laserfiche WebLink

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Municipal Stormwater Permittees Page 2 January 19, 2U 1 Q Background Information Coal tar is a byproduct of coal processing which contains high levels of toxic chemicals calked polycyclic aromatic hydrocarbons ~PAHs}. Some PAHs are classed as probable or possible carcinogens to humans. Coal tar is used in pavement sealers commonly called seal coat. Studies show that PAHs can be released and flushed by stormwater runoff into nearby surface waters. PAHs have been found to accumulate in sediments at potentially harmful levels when seal coat flakes off parking lots and driveways and is washed into stormwater ponds and other water bodies. This is a concern for anyone responsible for managing and disposing of stormwater related sediments. A study has also linked coal tar sealers to higher levels of PAHs in dust found indoors near seal-coated parking lots. The Potentiai for High Cost to Manage~~Contaminated Sediments In 2007 the city of White Bear Lake was confronted with costs of approximately $250,000 to manage contaminated sediment for just two ponds. The concentration of PAHs in the sediments and the costs to manage them is not unique to this community. PAH contamination is occurring in stormwater ponds and other waters across the state with some studies suggesting that PAH contamination is more concentrated in densely urbanized areas such as the seven-county metropo itan area. . Work Being Done The MPCA is taking action to; 1. Notify state agencies about the coal tar restriction. This work is being done using newsletters and a-mails in collaboration with the Minnesota Department of Administration. 2. Get the word out to Minnesota municipalities, stakeholders, and citizens about the potential for PAH contamination in stormwater ponds. This work is being done through the MPCA web site, a-mail, newsletters and irk collaboration with the League of Minnesota Cities. 3. Develop guidance and best management practices for treating and cleaning up contaminated sediments. The MPCA has a guidance document called Managing Urban Stormwater Ponds to assist Municipal Separate Storm Sewer Systems ~M54~ communities with the management of contaminated sediments. 4. Create a model ordinance for restricting the use of coal tar sealers. The model ordinance is being developed in collaboration with the League of Minnesota Cities and will be made available to Minnesota municipalities in early 2410. Currently Dane County, Wisconsin, Washington D.C., and Austin, Texas have developed ordinances and enacted laws to restrict the use of coal tar sealers. 5. Fund research at the University of Minnesota to determine if biodegradation through composting of sediments could be a viable management option.