1. Environmental Effects of Coal Tar-Based Pavement Rejuvenators
Seth M. MacDonald (CEE), Caroline D. Meyer (CEE)
Advisor: Professor John Bergendahl, Ph.D., P.E. (Civil and Environmental Engineering)
Abstract
Coal tar-based sealcoats and rejuvenators have been under scrutiny due to the high concentrations of polycyclic aromatic hydrocarbons (PAHs) in the coal tar base. Researchers have found that PAHs mobilize from coal tar sealcoats and coal tar-based sealcoats have been banned in many locations in the U.S. due to the concerns over carcinogenic and mutagenic effects of the PAHs they contain. In this research, the environmental impacts of a coal tar-based pavement rejuvenator was investigated. The purpose of this project was to quantify PAHs mobilized from a coal tar-based rejuvenator by evaluating surface coating samples, street dust samples, and catch basin sediment samples for total PAHs. Samples were collected from a neighborhood in New England where the coal tar-based product was applied in Total PAH concentrations were quantified in the samples using a solvent extraction method and gas chromatography. Alternative pavement maintenance processes and products were explored.
Analysis and Results
One g of each sample was mixed with 10 mL of MeCl, placed in a sonication bath for 5 minutes for chemical extraction, and transferred using a syringe and filtered through single use RC- membrane filters with 0.2㎛ pores into 1.5 mL vials to be analyzed using a gas chromatograph.
Carcinogenic Potential of Individual PAHs
PAH
Known Animal Carcinogen
Possible Human Carcinogen
Probable Human Carcinogen
Benz(a)anthracene
Benzo(b)fluoranthene
Benzo(a)fluoranthene
Benzo(a)pyrene
Dibenz(a,h)anthracene
Indeno(1,2,3-c,d)pyrene
Benzo(k)fluoranthene
Chrysene
6890 GC with 7683 Series Injector and AutoSampler
Agilent Tech (30m x 0.25mm) column
Temp: 35 C for 4 min. -> (3.00 C/min) -> 50 C  -> (8.00 C/min) -> 290 C for 3 min.
Temp of inlet: 300 C
Injection Volume: 2.0 ㎛, injected splitless with helium carrier gas
Individual PAH Concentrations in Surface Coating Samples
Objectives
Quantify the total PAH concentration in the surface coating of a coal tar-based rejuvenator applied to the study site,
2. Investigate PAH mobilization from a coal-tar based rejuvenator into catch basin sediments,
3. Recommend other types of rejuvenators that would minimize ecological risks, and
4. Recommend future investigative avenues to elucidate the environmental impacts of coal tar-based rejuvenators.
Amphibian Exposure Levels adapted from (Bryer et al., 2006), Benthic (Bryer et al., 2010).
Study Site, Sampling Methods,
and Locations
A coal tar-based rejuvenator was applied to pavement in a neighborhood in Pomfret, CT. Four types of samples were collected from the study site and analyzed throughout a five month period for total PAH compounds: pavement surface dust samples, road surface coating samples, sediment samples from catch basins.
Recommendations
Further investigation into the fate and transport of the PAH-laden dust particles
Additional research should look at the potential aquatic toxicity and human health impacts from this mobilized material.  
Site Photos
Acknowledgements
Lab Support: Donald Pellegrino, Dr. Jose Rivera Alverez Corena
Expert Consultants: Drs. Peter C. VanMetre and Barbara J. Mahler
References
Bryer, P. J., Elliott, J. N., & Willingham, E. J. (2006). The Effects of Coal Tar Based Pavement Sealer on Amphibian Development and Metamorphosis.
Bryer, P. J., Scoggins, M., & McClintock, N. L. (2010). Coal-tar based pavement sealant toxicity to freshwater macroinvertebrates. Environmental Pollution, 158(5), 1932–1937.
Above: Basketball after use at study site, 7/16
Right Top: Pavement after application of rejuvenator
Right Bottom: Reference site pavement surface