|Complete Exposure Pathways at Schools from Coal Tar Sealants|U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES, Public Health Service Agency for Toxic Substances and Disease Registry, Division of Health Assessment and Consultation: Health Consultation for Leander Independent School District, Proposed Elementary School #19, (Grandview Hills Elementary), Austin, Travis County, Texas, EPA FACILITY ID: TXN000606777, February 13, 2008.
- For years it was hoped that the federal government toxicologists would just look at the safety of children exposed to coal tar sealants. A few years ago it was discovered that they already had, but it was coincidental. A school district outside of Austin, Texas (Leander) was looking to build a new elementary school. They purchased a property that met their needs except that it had been a chemical research facility. When parents found out, many were very upset. So upset that they got the attention of their elected officials, who in turn brought in the feds (more specifically the Agency for Toxic Substances and Disease Registry ATSDR, who routinely does this kind of work).
Mutagenicity and PAC Content of Seal Coatings for Asphalt Pavement. Mackerer, C. R. et al; 16th International Conference on Polycyclic Aromatic Compounds, November 1997.
- They tested the soil and analyzed the risks. They found relatively high levels (69 mg/kg, but nothing near the highest in pavement dust by the USGS: 3200 mg/kg) of polycyclic aromatic hydrocarbons (PAHs) in the soil near where there were parking lots and the source was determined to be coal tar pavement sealants. The levels were sufficient to increase cancer risk in a low to moderate range if it remained at the proposed site. As a result soils were removed under the description of "remediaton."
- We continue to hear some say that coal tar sealants have the toxic ingredients refined out (generally polycyclic aromatic hydrocarbons, PAH). This in spite of the laboratory levels of showing extremely high concentrations.
- A few years ago, I came across this research that got little attention when presented back in 1997. It pre-dates any of the current understanding of the problem of coal tar sealants. The lead author is the retired head of the Mobil Corporation's research laboratory. He developed an index to rate the mutagenicity of chemical solutions called the Ames Index. It has been used on other coal or petroleum products as well.
- Dr. Mackerer decided to do this study after seeing some college students sealing his neighborhood's driveways. He wondered just how toxic the sealants are. So he went to a hardware store and bought 12 separate products. As the above graph shows, anything above 1.0 is considered a mutagen. The coal tar sealants are an average of about 450! Dr. Mackerer said that while the absolute number can go higher, after a few hundred the real mutagenicity is maxed out.
- The only problem with this is that it has never been published, but is only a collection of slides summarizing the team's work.
Human Health Studies Regarding PAH EffectsEffects of Prenatal Exposure to Air Pollutants (Polycyclic Aromatic Hydrocarbons) on the Development of Brain White Matter, Cognition, and Behavior in Later ChildhoodResidential Proximity to Freeways and Autism in the CHARGE Study, Environ Health Perspect. 2011 June.
. Peterson, B; Rauh, V; Bansal, R; Hao, X; Toth, Z; Nati, G; Walsh, K; Miller, R; Arias, F; Semanek, D; Perera, F. JAMA Psychiatry, 2015.
Association of childhood obesity with maternal exposure to ambient air polycyclic aromatic hydrocarbons during pregnancy.
- Our findings suggest that prenatal exposure to PAH air pollutants contributes to slower processing speed, attention-deficit/hyperactivity disorder symptoms, and externalizing problems in urban youth by disrupting the development of left hemisphere white matter, whereas postnatal PAH exposure contributes to additional disturbances in the development of white matter in dorsal prefrontal regions.
Rundle A, Hoepner L, Hassoun A, Oberfield S, Freyer G, Holmes D, Reyes M, Quinn J, Camann D, Perera F, Whyatt R; Am J Epidemiol. 2012 Jun 1;175(11):1163-72. Epub 2012 Apr 13.
Prenatal Airborne Polycyclic Aromatic Hydrocarbon Exposure and Child IQ at Age 5
- The data indicate that prenatal exposure to PAHs is associated with obesity in childhood.
, Pediatrics, Jul 20, 2009.
Effect of Prenatal Exposure to Airborne Polycyclic Aromatic Hydrocarbons on Neurodevelopment in the First 3 Years of Life among Inner-City Children, Environ Health Perspect. 2006 August.
- Researchers at the Center for Children's Environmental Health (CCCEH) at the Mailman School of Public Health find that exposure to urban air pollution during pregnancy can result in lower IQ in children. Air pollutants known as PAH’s (polycyclic aromatic hydrocarbons) mostly come from traffic sources, including burning diesel fuel. Burning tobacco also releases PAHs. The result of burning fossil fuels is now linked to lower IQ, and the effects occur before birth.
Coal-tars and Derived products. 1985 International Agency for Research on Cancer (IARC) vol 35, 83 p.
- Living near a freeway was associated with autism. Examination of associations with measured air pollutants is needed.
Biological and Ecological Health
- This landmark document describes the carcinogenic properties of coal tars and coal-tar pitches, and finds that there is sufficient evidence that coal-tar pitches are carcinogenic in humans.
Exposure to runoff from coal-tar-sealed pavement induces genotoxicity and impairment of DNA repair capacity in the RTL-W1 fish liver cell line. Kienzler, A; Mahler, B; Van Metre, P; Schweigert, N; Devaux, A; Bony, S. Science of the Total Environmental, July 2015.
- Runoff from coal-tar-sealed pavement, diluted 1:100, causes DNA damage when cells also are exposed to ultra-violet radiation that mimics sunlight.
- Runoff from coal-tar-sealed pavement, diluted 1:10, impairs the ability of cells to repair DNA damage.
- Runoff from freshly applied coal-tar sealcoat is acutely toxic to two test organisms (fathead minnows (Pimephales promelas) and a water flea (Ceriodaphnia dubia)).
Toxicity of coal—tar and asphalt sealants to eastern newts, Notophthalmus viridescens. 2010. Bommarito, T., Spading, D.W., and Halbrook, R.S.
- Toxic effects to test organisms continue for samples collected as long as 111 (3+ months) days following application if organisms also are exposed to ultra-violet light mimicking sunlight.
Toxicity of coal-tar pavement sealants and ultraviolet radiation to Ambystoma Maculatwn. 2010. Bommarito, T., Sparling, D.W., and Halbrook, R.W.
- This scientific journal article reports that exposure of eastern newts to sediment contaminated with coal-tarbased sealcoat resulted in deleterious effects, including difficulty right themselves, impaired ability to swim, and diminished liver enzyme activities.
Coal-tar based pavement sealant toxicity to freshwater macroinvertebrates. Bryer, P.J., Scoggins, M., and McClintock, N.L., 2009. Environmental Pollution, v. 158, no. 5, p. 1932-1937.
- This scientific journal articles reports that spotted salamanders exposed to sediment contaminated with coal-tar-based sealcoat in sediment had slower rates of growth and diminished ability to swim. Subsequent exposure to ultra-violet radiation resulted in genetic damage.
Occurrence of polycyclic aromatic hydrocarbons below coal-tar-sealed parking lots and effects on stream benthic macroinvertebrate communities. Scoggins, M., McClintock, N., Gosselink, L., and Bryer, P., 2007. Journal of the North American Benthological Society, v. 26, no. 4, p. 694-707.
- This scientific journal article reports that exposure to sediment contaminated with coal-tar-based sealcoat resulted in decreased abundance and richness of freshwater macroinvertebrates, an important element in the aquatic food chain.
- This scientific journal article reports a significant decrease in the health of the ecological community downstream from points of discharge of runoff from coal-tar-sealcoated parking lots relative to ecological communities upstream.
The effects of coal tar based pavement sealer on amphibian development and metamorphosis. 2006. Bryer, P.J., Elliott, J.N., and Willingham, E.J. , Ecotoxicology, vol. 15(3), 241-247.
Coal Tar Sealant Concentrations, Use, and Mobility
- This scientific journal article reports that exposure to sediment contaminated with coal-tar-based pavement sealer resulted in stunted growth and slower development of the frog Xenopus laevis.
PAH Concentrations in Lake Sediment Decline Following Ban on Coal-Tar-Based Pavement Sealants in Austin, Texas
. Van Metre, P; Mahler, B. Environmental Science and Technology, June 2014.
Coal-tar-based pavement sealcoat and PAHs: Implications for the environment, human health, and stormwater management
- This USGS fact sheet provides an overview of the ways in which coal-tar-based sealcoat contaminates pavement dust, lake sediment, and house dust.
. Mahler, B.J.; Van Metre, P.C.; Crane, J.L.; Watts, A.W.; Scoggins, M.; Williams, E.S., Environ. Sci. Technol., 2012.
Parking lot sealcoat: An unrecognized source of urban PAHs. Mahler
- This feature article in Environmental Science and Technology summarizes the ways in which coal-tarbased sealcoat contaminates stormwater runoff, lake sediment, soil, house dust, and air, and implications for human and biological health and stormwater management.
, B. J.; Van Metre, P. C.; Bashara, T. J.; Wilson, J. T.; Johns, D. A., Environ. Sci. Technol. 2005, 39, (15), 5560-5566.
Contamination of Stormwater Pond Sediments by Polycyclic Aromatic Hydrocarbons (PAHs) in Minnesota
- This article was the first to report the potential for coal-tar-based pavement sealcoat to be an important source of PAH contamination. The study of runoff from 13 parking lots found that concentrations of PAHs in particles in runoff from pavement with coal-tar-based sealcoat was, on average, 65 times higher than concentrations in particles in runoff from unsealed asphalt parking lots.
: The Role of Coal Tar-based Sealcoat Products as a Source of PAHs. Crane, J.L., Grosenheider, K., and Wilson, C.B., 2010, Minnesota Pollution Control Agency, 64 p.
- This white paper by the Minnesota Pollution Control Agency describes the filling of stormwater ponds with PAH-contaminated sediments, the expense of deposing of the sediments, and the likelihood that coal-tarbased pavement sealants are a substantial contributor to the problem.
Concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) and Major and Trace Elements in Simulated Rainfall Runoff from Parking Lots, Austin, Texas, 2003. Mahler, Barbara J.; Van Metre, Peter C.; Wilson, Jennifer T. 2004. USGS OFR 2004-1208. http://pubs.usgs.gov/of/2004/1208/
Trends in Hydrophobic Organic Contaminants in Lake Sediments Across the United States, 1970-2001
. Van Metre, P.C. and Mahler, BJ., 2005. Environ. Sci. Technol., v. 39, no. 15, p. 5567-5574.
PAHs underfoot: Contaminated dust from coal-tar sealcoated pavement is widespread in the United States.
- This scientific journal article documents upwards trends in PAH contamination in sediment in urban lakes across the United States.
Van Metre, P. C.; Mahler, B. J.; Wilson, J. Environ. Sci. Technol. 2009, 43, (1), 20-25. Environ. Sci. Technol. 2009, 43, (1), 20-25.
Polycyclic aromatic hydrocarbons in stormwater runoff from sealcoated pavements.
- This scientific journal article reports that concentrations of PAHs in dust swept from parking lots across the central, southern, and eastern U.S.—where coal-tar-based sealcoat use is most common—are in the 1000s of mg/kg, concentrations similar to those in contaminated soils of USEPA Superfund Sites.
Watts, A.W., Ballestero, T.P., Roseen, R.M., and House, J.P., Environ. Sci. Technol. 2010, v. 44(23), 8849-8854.
Influence of coal-tar sealcoat and other carbonaceous materials on polycyclic aromatic hydrocarbon loading in an urban watershed.
- This scientific journal article reports that even partial coverage of a drainage area by coal-tar-based sealant resulted in increased PAH concentrations in sediment. A stormwater swale receiving runoff from both sealed and unsealed lots had PAH concentrations 25 times higher after sealant was applied than prior to sealant application.
Yang, Y., Van Metre, P.C., Mahler, B.J., Wilson, J.T., Ligouis, B., Razzaque, M.M., Schaeffer, D.J., and Werth, CJ., 2010,: Environ. Sci. Technol., v. 44, p. 1217-1223.
Contribution of PAHs from Coal-Tar Pavement Sealcoat and Other Sources to 40 U.S. Lakes
- This scientific journal article reports research using organic petrography to quantitatively determine the proportion of PAHs in dust and soil samples originating as coal-tar pitch. The study found that coal-tar pitch, used in coal-tar-based sealcoat, was a dominant source of PAHs in the watershed, contributing as much as 99% of the PAHs in sealed parking lot dust, 92% in unsealed parking lot dust, 88% in commercial area soil, 71% in streambed sediment, and 84% in surficial lake sediment.
. Van Metre, P. C.; Mahler, B. J. Sci. of the Total Environ., 2010, v.409, 334-344.
Volatilization of polycyclic aromatic hydrocarbons from coal-tar-sealed pavement.
- This scientific journal article reports that coal-tar-based sealcoat was, on average, the largest source of PAHs to sediment in 40 U.S. lakes, on the basis of a statistical source-apportionment approach. The article also reported that coal-tar-based sealcoat was the source of upward trends in PAH concentrations in seven of eight urban lakes investigated.
Van Metre, P. C.; Majewski, M. S.; Mahler, B. J.; Foreman, W. T.; Braun, C. L.; Wilson, J. T.; Burbank, T. Chemosphere, 2012.
PAH volatilization following application of coal-tar-based pavement sealant.
- This scientific journal article reports PAH releases to air from in-use parking lots with and without coal-tarbased sealcoat. The mass of PAHs released to air per unit area of coal-tar-sealed pavement was 60 times greater than that released from unsealed asphalt pavement, even though in all but one case the sealant had been applied from 3 to 8 years prior to sampling.
Van Metre, P. C.; Majewski, M. S.; Mahler, B. J.; Foreman, W. T.; Braun, C. L.; Wilson, J. T.; Burbank, T. Atmos. Environ. 2012.
- This scientific journal article reports enormous releases of PAHs to the atmosphere (one-quarter to one-half of the PAHs contained in the product) during the 15 days following application of coal-tar-based sealant. The authors estimate that PAH emissions from new coal-tar-based sealcoat applications each year (-1000 Mg) are larger than annual vehicle emissions of PAHs for the United States.