title: Article title misstates the role of pavement sealers.
abstract: The claim made in the title of Witter et al. (2014) "Coal-tar-based sealcoated pavement: A major PAH source to urban stream sediments" is not supported by the data presented. The author's use of Pearson correlation coefficients is insufficient to indicate causation. The application of spatial analysis and principle component analysis did not include sealer specific inputs, so provides no basis for the claim. To test the hypothesis that sealers are a source of PAHs in the stream studied, EPA's Chemical Mass Balance (CMB) source evaluation model was applied to Witter's sediment data. CMB found an excellent fit (R(2) > 0.999) between measured and modeled PAH concentrations when sealers were not included as a potential source. This finding does not support Witter et al. (2014) claim that sealers are a major source of PAHs.
authors.affiliation: Exponent, Inc., 15375 S.E. 30th Place, Suite 250, Bellevue, WA 98007, USA. Electronic address: koreilly@exponent.com.
authors.forename: Kirk
authors.initials: K
authors.lastname: O'Reilly
mesh_terms: D003033:Coal Tar / Q000032:analysis*; D004784:Environmental Monitoring; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D003033:Coal Tar
keywords: CMB; PAH; Pavement sealer; Sediment