The comment below will be posted on the post-publication peer review (PPPR) web site, PubPeer.com. At present, the PubPeer link to the Pavlowsky paper is not working properly.
UPDATE: The problem is that the DOI (Digital Object Identifier) for Pavlowsky (2013) as listed on the journal’s web site is DOI:10.1080/02723646.2013.848393. Entering that DOI in PubPeer.com’s search engine leads to a different paper published in a different journal.
Pavlowsky (2013) was based on a report prepared for the City of Springfield, Missouri (Pavlowsky, 2012). As is usually the case when a published paper is based on a report, the report contains more detail about the study than the published paper. A Comment (Gauthier & DeMott, 2015) on the paper was published in the journal Physical Geography simultaneously with the author’s Response (Pavlowsky, 2015). The Comment (Gauthier & DeMott, 2015) summarized a PPPR commissioned by the Pavement Coatings Technology Council (PCTC). The PPPR report (Gauthier, 2014) and the report submitted to the City of Springfield (Pavlowsky, 2012) are available at the links provided here and in the reference list at the end of this post.
Gauthier & DeMott’s (2015) detailed evaluation of sediment classifications and statistical analysis presented in Pavlowsky (2012, 2013) is summarized in the following paragraph.
In a recent article, Pavlowsky (2013) concludes that parking lots with coal-tar coatings contribute more than 80% of the total polycyclic aromatic hydrocarbon (PAH) concentration in urban stream and pond sediments in Galloway Creek, and that banning the use of coal-tar sealants could result in a potential 80–99% reduction in sediment PAH levels. Since most PAHs enter the environment as combustion byproducts (Valle, Panero, & Shor, 2007) with motor vehicles representing a major source of PAHs in urban areas (Christensen & Bzdusek, 2005; Van Metre, Mahler, & Furlong, 2000), we questioned the accuracy of the claims and found the conclusions to be based on a flawed regression model that (a) relies primarily on parking lot samples rather than Galloway Creek sediments, (b) cannot mathematically account for parking lot areas with no sealer applied due to inappropriate use of logarithms, and (c) includes “independent” variables that are significantly correlated with each other and not truly independent – introducing potential issues of multicollinearity. Moreover, the author uses sealed lot area as a proxy for coal-tar coatings without attempting to address the fraction of coatings that are coal-tar-based as opposed to asphalt-based. In our opinion, these are critical flaws that undermine the conclusions in the study.
The photograph at the top of this post shows the location of sample 41, which was included in the statistical analysis of “downstream sediment” by Pavlowsky (2012, 2013).
Gauthier, T. D. (2014). Initial Review of the Pavlowsky Paper. Post-Publication Peer Review Report prepared by Environ for the Pavement Coatings Technology Council. Available at http://www.pavementcouncil.org/wp-content/uploads/2016/01/Pavlowsky-Memo.pdf
Gauthier, T. D., & DeMott, R. P. (2015). Comment on “Coal-tar pavement sealant use and polycyclic aromatic hydrocarbon contamination in urban stream sediments” Physical Geography 34, 4–5, 392–415 (2013). Physical Geography, 36(1), 84-86. doi:10.1080/02723646.2014.981779
Pavlowsky, R. T. (2012). Baseline Study of PAH Sources and Concentrations in Pond and Stream Sediments, Springfield, Missouri (OEWRI EDR-12-002). Report prepared by The Ozarks Environmental and Water Institute of Missouri State University for the City of Springfield, Missouri. Retrieved from http://oewri.missouristate.edu/assets/OEWRI/PAH.pdf
Pavlowsky, R. T. (2013). Coal-tar pavement sealant use and polycyclic aromatic hydrocarbon contamination in urban stream sediments. Physical Geography, 34(4-05), 392-415. doi:http://dx.doi.org/10.1080/02723646.2013.848393
Pavlowsky, R. T. (2015). Response to “Comment on ‘Coal tar pavement sealant use and polycyclic aromatic hydrocarbon contamination in urban stream sediments’ in Physical Geography 34(4–5): 392–415” by T. D. Gauthier and R. P. DeMott. Physical Geography, 36(1), 87-92. doi:10.1080/02723646.2014.981780