There are a couple of ways to tackle the problem of polluted runoff: keep the water from getting fouled in the first place, or clean it up once it’s contaminated. It doesn’t take a hydrology expert to figure out that in many cases, it’s cheaper and easier to deal with a pollutant at its source before it’s dissolved in water and spread far and wide.
So goes the logic behind HB 1721, a bill proposed in Olympia that would ban the sale and application of coal-tar pavement sealants beginning next year. The sealants are applied to parking lots and driveways to make the asphalt longer lasting and give it a rich, black appearance. Trouble is, it doesn’t stay put. Like the paint on the side of your house, over time the sealant crumbles and peels off. When the rain hits the driveway or parking lot, it sponges up the bits of sealant and carries it away with the stormwater, depositing it into streams, rivers, lakes, and bays.
As you might expect from something called coal-tar pavement sealant, the product contains some nasty stuff. It has super high levels of polycyclic aromatic hydrocarbons, or PAHs, several of which are considered likely to cause cancer in people and can cause mutations or even kill tadpoles, herring, and other wildlife.
A study by the US Geologic Survey released in December found that in numerous lakes across the nation, the majority of PAHs polluting the waterbodies came from coal-tar sealants. Mud taken from Lake Ballinger in Mountlake Terrace, Wash., measured PAHs at 16.61 parts per million, with 11.83 ppm coming from the sealant. (The USGS reports harmful effects on wildlife and plants at 22.8 ppm.)
And the good news? There’s a lower-PAH alternative already in wide use.
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In Western states, the most commonly used sealant is asphalt-based, while the coal-tar version is more prevalent in the central, southern, and eastern US. But the coal-tar sealant is readily available online nationwide (though it is banned in some places), and the USGS research shows it’s certainly in use in Washington. The coal tar used to make the sealant is a waste product from steel manufacturing, explains Robert McClure in an msnbc story on the pollutant.
When you line up the coal-tar sealant versus the asphalt-based product, the former has PAH levels up to 1,000 times higher than the latter.
So we’ve got a dangerous product that’s contaminating stormwater and Northwest waterways with toxic compounds, and there’s a safer alternative available. What’s a lawmaker to do?!
Hopefully they’ll follow an example set last year when many of the same Washington legislators banned the use of copper brake pads in cars and trucks (California approved a similar ban later in the year). Again, in an effort to cleanup poisoned stormwater, the leaders targeted a prime source of toxic copper in the environment and are requiring manufacturers to switch to safer alternatives.
A hearing on the coal-tar sealant legislation, whose prime sponsor is Rep. David Frockt, D-Seattle, is scheduled for Feb. 8 at 1:30 pm in Olympia.
Parking lot photo from Flickr user jgrimm used under the Creative Commons license.
Congrats to the sponsors of this bill for bringing this forward!Could the State of Washington be the first to ban this at the state level? Minnesota has begun to move toward this and Michigan has also introduced legislation., The sooner you stop, the sooner the improvements in the environment and your health can begin!You can learn more about Austin’s experience with this product with some other interesting info on my blog at: http://coaltarfreeamerica.blogspot.com/
I love how Tom from City of Austin always crops up. Did you happen to mention to Washington state that after 2.5 years that PAH levels did not drop nor did the composition change? I know you are fond of saying that you have reduced PAH levels by 1 million pounds since the ban (too bad you have no way to back that up).How come the environmental forensics evidence does not show sealer to be the contributor that you, Babs and Peter claim it is?I guess that no one mentioned to WA state how Peter and Babs are advocate scientist, who believe in their version of the scientific method.www.truthaboutcoaltar.comIt is a much nicer site than Tom’s blog.Mantis
No Change in Amount or Sources of PAHs in Austin, Texas Years After Product BanPAH Fingerprints Do Not Identify Pavement Sealants as SourceALEXANDRIA, Va., Dec. 9, 2010 /PRNewswire-USNewswire/—More than two years after Austin, TX banned refined tar sealants, there has been no discernable change in either the amount or sources of polycyclic aromatic hydrocarbons in sediment in Austin’s waterways. Austin’s ban went into effect on January 1, 2006. Results of a study of the ban’s impact were just published in a paper titled Polycyclic Aromatic Hydrocarbons (PAHs) in Austin Sediments After A Ban on Pavement Sealers in Environmental Forensics, the journal of the International Society of Environmental Forensics. Samples were collected from Austin’s streams before the ban, in October 2005, and again after the ban in April 2008. Total concentrations of PAHs in sediments before and after the ban did not change, as might be expected if sealants were the principal source of PAHs in sediments. According to the study’s author, Dr. Robert DeMott, the variation in individual PAHs is expected because PAHs are so common in so many different products. PAHs in the Austin samples were also evaluated using environmental forensics techniques. PAH fingerprinting of sediments collected before and after the ban did not identify any marked changes.PAHs are everywhere in the environment and are formed by burning organic matter.. PAHs are found in used motor oil, grilled meats and vegetables, exhaust from internal combustion engines and emissions from fossil fuel power plants, forest fires and volcanoes as well as products made from coal and petroleum. The follow-up study of sediments in Austin as well as the results of a PAH fingerprinting study presented at a recent meeting of the Society of Environmental Toxicology and Chemistry (SETAC) indicate that pavement sealants are not the principal source of PAHs in downstream sediments, as has been suggested by others. Both studies were sponsored by the Pavement Coatings Technology Council, which researches and promotes environmentally responsible practices by sealcoat applicators.http://www.pavementcouncil.orgLink to the article: http://dx.doi.org/10.1080/15275922.2010.526520