Scientific Studies on Coal Tar Sealcoats

Scientific Studies on Coal Tar Sealcoats

Mahler, B.J.; Van Metre, P.C., You’re Standing On It! Coal Tar Based Pavement Sealcoat and Environmental and Human Health. APWA Reporter, Feb. 2013, p. 64-66. This article provides a basic compilation of information on coal tar sealcoats, pollution, and human health risks.

Van Metre, P. C.; Mahler, B. J., Contribution of PAHs from Coal-Tar Pavement Sealcoat and Other Sources to 40 U.S. Lakes. Sci. of the Total Environ., 2010, v.409, 334-344. Coal tar sealcoat is the largest source of PAH contamination to urban lakes and the primary cause of upward PAH trends in urban lake sediment.

Yang, Y., Van Metre, P.C., Mahler, B.J., Wilson, J.T., Ligouis, B., Razzaque, M.M., Schaeffer, D.J., and Werth, C.J., 2010, Influence of coal-tar sealcoat and other carbonaceous materials on polycyclic aromatic hydrocarbon loading in an urban watershed: Environ. Sci. Technol., v. 44, p. 1217-1223. Coal tar pitch from coal tar sealcoat pavements reaches streams and lakes via runoff and also ends up on unsealed pavement near sealed parking lots.

Mahler, B.J., Van Metre, P.C., and Foreman, W.T. Concentrations of polycyclic aromatic hydrocarbons (PAHs) and azaarenes in runoff from coal-tar- and asphalt-sealcoated pavement. Environ. Pollut., v. 88, p. 81-87. PAH concentrations in runoff from pavement treated with coal tar sealcoat remained elevated for months following the application of the sealcoat.

Van Metre, P. C.; Majewski, M. S.; Mahler, B. J.; Foreman, W. T.; Braun, C. L.; Wilson, J. T.; Burbank, T. PAH volatilization following application of coal-tar-based pavement sealant. Atmos. Environ. 2012. PAH emissions to the air two hours after application of coal tar sealcoat were found to be 30,000 times greater than from unsealed pavement. Estimated total annual PAH emissions from newly applied coal tar sealcoats likely exceeds PAH emissions from vehicles in the U.S.

Van Metre, P. C.; Majewski, M. S.; Mahler, B. J.; Foreman, W. T.; Braun, C. L.; Wilson, J. T.; Burbank, T. Volatilization of polycyclic aromatic hydrocarbons from coal-tar-sealed pavement. Chemosphere, 2012. Emissions of PAHs to the air from parking lots with older (three to eight years) coal tar sealcoat pavements are 60 times greater than from pavements not treated with coal tar sealcoat.

Mahler, B. J.; Van Metre, P. C.; Wilson, J. T.; Musgrove, M.; Burbank, T. L.; Ennis, T.; Bashara, T. J., Coal-tar-based parking lot sealcoat: An unrecognized source of PAH to settled house dust. Environ. Sci. Technol. 2010, 44, 894-900. Dust in residences adjacent to parking lots with coal tar sealcoat have elevated concentrations of PAHs.

Van Metre, P. C.; Mahler, B. J.; Wilson, J., PAHs underfoot: Contaminated dust from coal-tar sealcoated pavement is widespread in the United States. Environ. Sci. Technol. 2009, 43, (1), 20-25. Environ. Sci. Technol. 2009, 43, (1), 20-25. PAH concentrations in dust from coal tar sealcoat pavements are hundreds to thousands of times higher than PAH concentrations in dust from pavement with no sealcoat or with asphalt based sealcoat.

Williams, E. S.; Mahler, B. J.; Van Metre, P. C. Coal-tar pavement sealants might substantially increase children’s PAH exposures. Environ. Pollut. 2012. Dust in residences with coal tar sealcoat pavement parking lots provide doses of carcinogenic PAHs through ingestion of the dust 14 times greater than the dust in residences with unsealed pavement. The doses are more than double the dose from ingesting PAHs through diet.

Williams, E.S.; Mahler, B.J.; Van Metre, P.C., Environ. Sci. Technol. 2012, v. 47 (2), 1101-1109. The estimated excess lifetime cancer risk is 38 times higher for those living adjacent to a coal tar sealcoat pavement and much of the increased risk occurs during early childhood.

 

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