USGS - science for a changing world

Texas Water Science Center

  Home Information/Data GIS Projects Publications DroughtWatch FloodWatch FAQ Contact   Internal

Coal-tar-based sealcoat being applied to a test plot.

Quick Questions

Pavement sealcoat, or sealant, is a black liquid that is sprayed or painted on asphalt pavement. It is marketed as protecting and beautifying the asphalt surface. Sealcoat is used commercially and by homeowners across the Nation.

Most sealcoat products have a coal-tar-pitch or asphalt base. Coal-tar-based sealcoat is most commonly used in the central, southern, and eastern U.S., and asphalt-based sealcoat is used predominantly in the western U.S.

Learn more more

 

Polycyclic aromatic hydrocarbons (PAHs) are a group of chemical compounds that form during the combustion of anything with a carbon base, from wood and gasoline to cigarettes and meat. PAHs also are found in products whose production involves the heating of hydrocarbons, such as automobile tires and coal-tar pitch.

PAHs are of environmental concern because several are toxic, carcinogenic, mutagenic, and(or) teratogenic (causing birth defects) to aquatic life and because several are probable human carcinogens.

Learn more more

 

Coal tar is a byproduct of the coking of coal, and can contain 50 percent or more PAHs by weight. Coal-tar pitch is known to cause cancer in humans (International Agency for Research on Cancer, 1985).

Coal-tar-based sealcoat products typically are 20 to 35 percent coal-tar pitch. Product analyses indicate that coal-tar-based sealcoat products contain about 1,000 times more PAHs than sealcoat products with an asphalt base (City of Austin, 2005).

Learn more more

PAH and Sealcoat Contacts

  • Barbara Mahler
    USGS Research Hydrologist
    (512) 927-3566
  • Peter Van Metre
    USGS Research Hydrologist
    (512) 927-3506
  • Mailing Address:
    U.S. Geological Survey
    1505 Ferguson Lane
    Austin, TX 78754

ABOUT THE TEXAS WSC

USGS IN YOUR STATE

USGS Water Science Centers are located in each state.

There is a USGS Water Science Center office in each State. Washington Oregon California Idaho Nevada Montana Wyoming Utah Colorado Arizona New Mexico North Dakota South Dakota Nebraska Kansas Oklahoma Texas Minnesota Iowa Missouri Arkansas Louisiana Wisconsin Illinois Mississippi Michigan Indiana Ohio Kentucky Tennessee Alabama Pennsylvania West Virginia Georgia Florida Caribbean Alaska Hawaii New York Vermont New Hampshire Maine Massachusetts South Carolina North Carolina Rhode Island Virginia Connecticut New Jersey Maryland-Delaware-D.C.

USGS Research: PAHs and Coal-Tar-Based Pavement Sealcoat
Publications

For more information about these publications and presentations, or to determine the availability of the publication or presentation materials, please contact Barbara Mahler

Publication Sections

Peer-Reviewed Scientific Journals

Mahler, B.J., and Van Metre, P.C., Coal-tar-based Pavement Sealants – A Potent Source of PAHs. Lakeline, 2017.

Van Metre, P.C., and Mahler, B.J., Trends and Sources of PAHs to Urban Lakes & Streams. Lakeline, 2017.

Baldwin, A.K., Corsi, S.R., Lutz, M.A., Ingersoll, C.G., Dorman, R., Magruder, C., Magruder, M., Primary sources and toxicity of PAHs in Milwaukee-area streambed sediment. Environmental Toxicology and Chemistry, 2016.

Mahler, B.J., Ingersoll, C.G., Van Metre, P.C., Kunz, J.L., and Little, E.E., Acute toxicity of runoff from sealcoated pavement to Ceriodaphnia dubia and Pimephales promelas. Environmental Science and Technology, 2015.

Kienzler, A., Mahler, B.J., Van Metre, P.C., Schweigert, N., Devaux, A., and Bony, S., Exposure to runoff from coal-tar-sealed pavement induces genotoxicity and impairment of DNA repair capacity in the RTL-W1 fish liver cell line. Science of the Total Environment, 2015.

Mahler, B. J.; Van Metre, P. C.; Foreman, W. T., Concentrations of polycyclic aromatic hydrocarbons (PAHs) and azaarenes in runoff from coal-tar- and asphalt-sealcoated pavement. Envion. Pollut. 2014, 188, 81-87.

Van Metre, P. C.; Mahler, B. J., PAH concentrations in lake sediment decline following ban on coal-tar-based pavement sealants in Austin, Texas. Environ. Sci. Technol. 2014, 48, 7222-7228.

Selbig, W. R.; Bannerman, R.; Corsi, S. R., From streets to streams: Assessing the toxicity potential of urban sediment by particle size. Science of the Total Environment 2013, 444, 381-391.

Williams, E. S.; Mahler, B. J.; Van Metre, P. C., Cancer risk from incidental ingestion exposures to PAHs associated with coal-tar-sealed pavement. Environ. Sci. Technol. 2013, 47, (2), 1101-1109.

Mahler, B.J.; Van Metre, P.C.; Crane, J.L.; Watts, A.W.; Scoggins, M.; Williams, E.S., Coal-tar-based pavement sealcoat and PAHs: Implications for the environment, human health, and stormwater management. Environ. Sci. Technol., 2012.

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.

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.

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.

Williams, E. S.; Mahler, B. J.; Van Metre, P. C. Coal-tar pavement sealants might substantially increase children's PAH exposures. Environ. Pollut. 2012.

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.

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.

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.

Mahler, B. J.; Van Metre, P. C.; Bashara, T. J.; Wilson, J. T.; Johns, D. A., Parking lot sealcoat: An unrecognized source of urban PAHs. Environ. Sci. Technol. 2005, 39, (15), 5560-5566.

Van Metre, P.C., and Mahler, B.J., 2005, Trends in Hydrophobic Organic Contaminants in Lake Sediments Across the United States, 1970-2001: Environ. Sci. Technol., v. 39, no. 15, p. 5567-5574.

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.

Van Metre, P.C. and Mahler, B.J., PAH Concentrations in Lake Sediment Decline Following Ban on Coal-Tar-Based Pavement Sealants in Austin, Texas. Environ. Sci. Technol., Article ASAP.
Article Supporting Information: text | tables

USGS Publications

Mahler, B.J., Woodside, M.D., and VanMetre, P.C., 2016, Coal-tar-based pavement sealcoat—Potential concerns for human health and aquatic life: U.S. Geological Survey Fact Sheet 2016-3017, 6 p.

Mahler, B.J., and Van Metre, P.C., 2011, Coal-tar-based pavement sealcoat, polycyclic aromatic hydrocarbons (PAHs), and environmental health: U.S. Geological Survey Fact Sheet 2011-3010, 6 p.

Van Metre, P. C.; Mahler, B. J.; Wilson, J. T.; Burbank, T. L. 2008. Collection and Analysis of Samples for Polycyclic Aromatic Hydrocarbons in Dust and Other Solids Related to Sealed and Unsealed Pavement From 10 Cities Across the United States, 2005-07. USGS Data Series 361.

Wilson, J.T., Van Metre, P.C., Werth, C.J., and Yang, Yanning, 2006 Particle-associated contaminants in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and streambed sediment, Lake Como and Fosdic Lake watersheds, Fort Worth, Texas, 2004: U.S. Geological Survey Data Series 211, 24 p.

Van Metre, P.C.; Mahler, B.J.; Scoggins, M.; and Hamilton, P.A., 2005. Parking Lot Sealcoat: A Major Source of Polycyclic Aromatic Hydrocarbons (PAHs) in Urban and Suburban Environments: U.S. Geological Survey Fact Sheet 2005-3147, 4 p (.pdf)

Mahler, Barbara J.; Van Metre, Peter C.; Wilson, Jennifer T. 2004. Concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) and Major and Trace Elements in Simulated Rainfall Runoff from Parking Lots, Austin, Texas, 2003. USGS OFR 2004-1208.
 
This report was subject to an "Information Quality Act" challenge from the sealcoat industry, to which the USGS responded. A press release summarized the USGS response.

Presentations

PAHs and coal tar—old contaminants with emerging concerns: presented by Barbara Mahler to Emerging Contaminants in Aquatic Environment Conference, June 1, 2017.

USGS Science on Coal-tar-based Sealcoat and Environmental and Human Health: presented by Barbara Mahler to Barrington Area Council of Governments, Oct 14, 2015

You're Standing On It! Coal-tar-based pavement sealcoat: Environmental and human-health overview: presented by Barbara Mahler at US Fish and Wildlife Service National Conservation Training Center, August 18, 2015

You're Standing On It! Coal-tar-based pavement sealcoat: Environmental and human-health overview: presented by Barbara Mahler at New York Water Science Center, May 29, 2015

Coal-tar-based pavement sealcoat: Health and environmental overview: presented by Barbara Mahler to the CDC and ATSDR, June 20, 2014

Coal-tar-based pavement sealcoat: Health and environmental overview: presented by Barbara Mahler at a Texas Water Science Center brownbag, December 5, 2013

PAHs, coal-tar sealants, and environmental health: presented by Barbara Mahler in a Congressional Briefing, Washington, D.C., April 14, 2011

PAH trends and the link to coal-tar sealants: presented by Peter Van Metre in the USGS Water Mission Area Lecture Series, 2011

Summary of USGS research on sealcoat: presented by Barbara Mahler to Society of Environmental Toxicology and Chemistry (SETAC), Portland, OR, 2010

Volatilization of PAHs from sealcoated pavement: presented by Peter Van Metre to Society of Environmental Toxicology and Chemistry (SETAC), Portland, OR, 2010

Sources of PAHs to urban lakes: presented by Peter Van Metre to Geological Society of America (GSA), Denver, CO, 2010

Relation of sealcoated parking lots and PAHs in settled house dust: presented by Barbara Mahler to Society of Environmental Toxicology and Chemistry (SETAC), New Orleans, LA, 2009

Magazine Articles

An article in the American Public Works Association member magazine (APWA Reporter, Feb. 2013, p. 64-66) provides a review of coal-tar-based sealcoat, environmental pollution, and human health for a lay audience.

Some USGS publications on PAHs and coal-tar-based pavement sealant have been subject to Information Quality Act correction requests. USGS Information Quality Guidelines, the correction requests, and USGS responses can be found at: http://tx.usgs.gov/infodata/infosealcoat.html

USGS Home Water Climate Change Core Science Ecosystems Energy and Minerals Env. Health Hazards

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://tx.usgs.gov/sealcoat/pubs.html
Page Contact Information: gs-w-txpublicinfo@usgs.gov
Page Last Modified: Friday, 09-Jun-2017 18:55:08 EDT

PAH Concentrations in Lake Sediment Decline Following Ban on Coal-Tar-Based Pavement Sealants in Austin, TX Press release Paint it Black