Baylor University unleashed social media with its announcement of a publication by university toxicologist, Dr. Spencer Williams. The press release was entitled, Proximity to Coal-Tar-Sealed Pavement Raises Risk of Cancer, Study Finds. While the twitter buzz is nothing like a teen craze, it has been significant for an issue that has long been ignored. Hundreds of tweets and retweets have been sent since last week. Just how much sustaining influence that has remains to be seen.
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| Does this warning sign now take on a new meaning? |
One positive result from the announcement is coverage by Rodale Press in Men’s Health Magazine (Your Neighborhood’s Cancer-Causing Secret). Not only did their article cover the press release, but it was also accompanied with fresh quotes from the researchers (like: “The increased cancer risk associated with coal-tar-sealed asphalt likely affects a large number of people in the U.S.,” says lead study author E. Spencer Williams, PhD, assistant research scientist at Baylor University’s Center for Reservoir and Aquatic Systems Research) and tips what to do next after one becomes aware of this issue.
Here are some of the suggestions on what to do:
• Create a no-shoes policy. PAHs are readily tracked into the home, so making family members and guests shed their shoes before entering the home can cut back on exposure.
• Don’t trust labels. If you don’t see the word “coal tar” on the sealant bucket, that doesn’t mean it’s necessarily coal-tar free, Mahler warns. There are dozens of names for coal tar, including RT12, distilled tar, or refined tar. “Tar,” is this instance, is a word you’ll want to avoid.
• Alert store managers and playground officials of the dangers of carcinogenic coal-tar sealants, and let them know that alternatives containing thousands of times fewer PAHs are readily available.
• Go for gravel
The press release was catching up to the published scientific journal that came out more than a month ago. The contents of our review of it are found below.
A recent scientific journal came out with little attention or really no media coverage at all. While there may be a variety of reasons why, my hunch is that part of the reason is that it contains some pretty complex and difficult concepts to communicate. Well I thought I would try to decipher a bit of that for you here.
The first task at making this a little more lay-friendly was to redo the above graph using data from the report. The essence of the paper is really contained in this graph. If you take your time to understand it, these are the key points:
- There is some cancer risk from ingestion from background PAH (polycyclic aromatic hydrocarbons) sources that we get from food and the environment, but it is in a risk range that the EPA would review on a case-by-case basis. This is why we frequently hear public service announcements to minimize eating grilled meat and exposure to tobacco smoke (incidental 2nd hand if you will).
- Any exposure scenario to from the proximity to coal tar sealed asphalt puts the risk into the zone of “desired remediation” or as stated previously “federally unacceptable.”
- Most exposure comes from coal tar sealant contaminated soil instead of indoor dust.
- Early childhood exposure is most troubling, but so is also in the red zone is a lifetime of exposure or even just exposure during adulthood.
The article, entitled “Cancer Risk from Incidental Ingestion Exposure to PAHs Associated with Coal Tar Sealed Pavements,” is a further refinement of work led by Dr. Spencer Williams, a toxicologist from Baylor University and co-authored by Drs. Barbara Mahler and Peter Van Metre of the USGS.
His work has been covered on Coal Tar Free America with the following posts:
- Cancer Risks of Coal Tar Sealant Exposed
- UConn PAH Seminar: Human Cancer Risks Federally “Unacceptable”
- Austin Schools Advance to the Head of the Class with Coal Tar Sealant Removal Plan
- Human Health, Coal Tar Sealants and PAH: the State of the Science
This is far from the last word that we will hear on the health effects of coal tar sealants. This paper covered just one exposure mechanism: ingestion. Also possible routes are inhalation and dermal. Also we have learned over the years that PAH’s cause many maladies, not just cancer, including birth defects, fertility, and IQ.
Do you now know enough to stop this practice in your sphere of influence, whether it is your driveway, business, church, school district, community or state?
A video of Dr. Williams presenting these findings is found here: