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PAH and Pavement Coat Sealer

Nobody likes driving over potholes in a parking lot, and a smoothly paved surface admittedly looks quite nice. But research shows the sealants that give parking lots their smooth surfaces are leaching known carcinogens, which can end up in local water supplies and also harm aquatic life.

Many parking lot sealants contain polycyclic aromatic hydrocarbons (PAHs) because they are made from coal tar. When cars drive over the lots, the friction from their tires breaks up the pavement and bits of the sealant often end up getting washed into local streams. When dangerously high levels of PAHs were found in a public swimming hole in Austin, TX – and traced to the parking lot of a nearby apartment complex – the city reacted by banning the sealants completely. Other regions are considering following suit.

In light of these findings, Home Depot and Lowes also stopped selling sealants containing PAHs. Now sealants that are free of PAH can be found on the market. But they are not yet the norm; roughly 85 million gallons of coal-tar-based sealants are sold in the United States each year.

As research continues to mount pointing to parking lots as the dominant source of PAH pollution in urban waterways, perhaps that will change.

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To read more about this and other environmental health issues, go to: www.environmentalhealthnews.org, www.ourstolenfuture.org, or www.healthandenvironment.org