Refined Tar-based Sealers Defended at International Conference

Two talks on topics relevant to refined tar-based pavement sealers (RTS) were presented at the recent International Symposium on Polycyclic Aromatic Compounds (ISPAC) Sept. 8-12 in Corvalis, OR.

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Kirk O’Reilly and co-authors presented Use of Receptor Models to Evaluate Sources of PAHs in Sediment. Using data obtained from the U.S. Geological Survey (USGS) via the Freedom of Information Act (FOIA), they were able to replicate published USGS modeling and test the results against both a negative control and a model run using different input parameters for RTS.

One of the authors’ conclusions is that the USGS hypothesis that RTS is a significant source of PAHs in sediments is not supported by receptor models, which are commonly used mathematical models intended to help identify sources of environmental pollution. O’Reilly’s presentation is posted on the website, here. Evaluation of the USGS use of receptor modeling forms part of the basis for’s first Data Quality Act (DQA) challenge, available here.

In a presentation titled Risk Assessment for Coal-Tar-Based Pavement Sealants, Brian Magee and co-authors, reviewed their recently completed peer review of a risk assessment collaboration between Baylor University and the USGS. The peer review documents the exaggerations and unexplained violations of risk assessment guidance in the Baylor/USGS effort. Dr. Magee’s presentation is posted on the website here, and the peer review report can be read here. The peer review report is an element of the third DQA challenge to be filed shortly by