Dr. Mahler explains how she linked RTS with Austin parking lot run off data

In the normal course of developing a study design with the goal of testing a hypothesis, the first step would usually be identifying effects that could confirm or negate the hypothesis. In the case of the USGS-Austin study, the hypothesis was that sealcoat was contributing some (large) percentage of PAHs to the local sediment load. Testing PAH concentrations of suspended particle load is interesting data to have, but of dubious relevance. The hypothesis is about PAHs in sediments. If the researchers lacked the resources to sample sediments at the time of the simulated rainfall sample collections, the City of Austin had many PAH analyses of sediments available in monitoring reports such as Geismar (2000) which could have been and, even if of lower quality than data produced by the USGS labs, should have been used as part of hypothesis testing. This begs the question: why were such data not used? It is impossible to ignore that, as shown in the DeMott and Gauthier (2006) double ratio plot, available sediment data did not yield a result that matched the preferred policy of the USGS researchers and Austin city staff. Even Austin city staff noticed, as made explicit in Scoggins et al. (2007). Yet, that is precisely was what was not done.

It is tempting to speculate that the many readily available bed load sediment PAH data and the available suspended particle load from stream sheds where the wash off studies were conducted were not used because they did not sufficiently match the PAH ratios of RTS-related samples. Conversely, it is tempting to speculate that the suspended particle data from Williamson Creek and the three Fort Worth streams were used because their PAH ratios were sufficiently similar. We need not speculate – Dr. Mahler herself provides the answer. In an email dated July 19, 2004, Dr, Mahler wrote:

When the Williamson Creek suspended sediment data was plotted on the same graph, they tended to group with the sealed parking lots as opposed to with the unsealed (asphalt pavement or cement) parking lots. Suspended sediment data from three small urban watersheds in Fort Worth were similar.

Thus Dr. Mahler confirms that it was precisely because PAH ratios of the 8 samples from Williamson Creek and the 12 from Fort Worth most closely matched RTS that they were chosen to represent Austin stream sediments. Data from other locations - including streams located next to parking lots that were part of the study - must not have matched as well, and so were not used. To suggest the results supported their hypothesis, the authors drew circles around the data on PAH double ratio plots to indicate that this urban background signal is more similar to RTS than it is to some other materials. The authors repeated this strategy in Van Metre et al (2009), presenting a double-ratio plot showing difference between urban sediments and a handful of PAH containing materials while suggesting this indicates the role of RTS. Highlighting these plots, while misstating their meaning, is evidence of advocacy research. Any other choice would have, from the USGS point of view, been inconclusive at best or, at worst, unsupportive of the USGS’ preferred policy.

And that preferred policy was then and remains today to ban the use of RTS.

Myron Knudson (EPA Region 6) letter to Toby Hammett Futrell (City of Austin, TX) dated April 17, 2003

Letter from Myron Knudson of EPA Region 6 to the City of Austin concerning the absence of health risks to swimmers using Barton Creek Pool.

How Laws are Made in Minnesota, Parts 1, 2 and 3

Emails obtained through a Minnesota-version of the a Freedom of Information Act (FOIA) request tell the story of how the Minnesota Pollution Control Agency pushed through a statewide ban on refined coal tar-based pavement sealers (RTS) using a mix bad science, unnecessarily burdensome regulation, misspent taxpayer dollars, and politicians led by federal and state employees with misguided policy preferences. In a multi-part series published in Pavement Maintenance & Reconstruction magazine, the emails tell the tale. Part 1 was published in March 2014 issue. Part 2 in May 2014. Part 3 was published in June 2014.

EPA’s Reliance On Outdated Studies Results in Challenge of Two Publications Regarding Refined Coal Tar-Based Sealants

PavementCouncil.org issued a press release today. The text follows:

ALEXANDRIA, Virginia, April 23, 2014 –.PavementCouncil.org submitted a Request for Correction (RfC) of information to the US Environmental Protection Agency (EPA) under the Data Quality Act (DQA). The RfC challenges the EPA’s reliance on outdated papers that offer theories about the alleged impact of refined coal tar-based sealants (RTS) on the environment. All of the studies cited by the EPA were published years ago by staff affiliated with the US Geological Survey (USGS) or the City of Austin. Most of the conclusions proffered in these publications have been called into question by more recent peer reviewed articles and comments published in well-respected scientific journals. Up to now, the more recent literature concerning RTS has been overlooked by the EPA. The RfC is available on EPA’s Information Quality web site.

PavemanPro.com publishes "A Contractor’s Letter to Customers Regarding Refined Coal Tar Sealers"

PavemanPro.com is a website that conveys information for and about asphalt professionals. Recently, a letter was published on PavemanPro.com from Atlanta contractor Gerry Signs, President of Asphalt Enterprises, Inc. The letter relates Mr. Signs decades of experience with both tar-based and asphalt-based sealers. Quite rightly, Mr. Signs points out that activists plan to follow their campaign against tar-based sealer by similarly targeting asphalt-based products. This exact sentiment has been expressed at different times in the presence of PCTC by, among others, the "Coal Tar Free America" blogger (whose day job is as an employee of the City of Austin, TX) and an employee of the Minnesota Pollution Control Agency.

Read the letter here: A Contractor’s Letter to Customers Regarding Refined Coal Tar Sealers

The Great Lakes Coal Tar Sealcoat PAH Reduction Project: Comments and Recommendations of the Pavement Coatings Technology Counci

PavementCouncil.org sent a letter to the organizations involved in the Great Lakes Coal Tar Sealcoat PAH Reduction Project ("Project"). Read the full letter here and the detailed comments and recommendations here.