United States Geological Survey: “Coal-Tar-Based Pavement Sealcoat, PAHs, and Environmental Health”

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The USGS published their findings on the effects of “Coal-Tar-Based Pavement Sealcoat, PAHs, and Environmental Health.” Check out their full findings and the article here and at the PDF linked below.

An excerpt:


Abraded dried sealcoat particles containing high concentrations of PAHs and related chemicals can be transported by rain, wind, car tires, and even our feet to surrounding areas, including our homes. Concentrations of PAHs in runoff, sediment, soils, and dust near coal-tar-sealcoated pavement are substantially higher than concentrations in those media near concrete pavement, unsealed asphalt pavement, and asphalt pavement with asphalt-based sealcoat.”

Diagram indicating pathways for transport of PAHs from coal-tar sealcoat

Coal-tar-based sealcoat is a potent source of PAHs and related chemicals. Worn particles of coal-tar-based sealcoat are transported by rain, wind, tires, and even our feet from pavement to other environmental settings. Sealcoat product (A), after it dries, gradually abrades to a powder and becomes part of the dust on the pavement (B). Pavement dust is transported by rainfall runoff (C) to stormwater-management devices (D) or to receiving streams and lakes (E). Pavement dust also adheres to tires (F) that track it onto unsealed pavement, and wind and runoff transport the dust to nearby soils (G). Sealcoat particles tracked into residences can become incorporated into the house dust (H). Graphic from USGS Fact Sheet 2016-3017.”

Download the PDF here.