Sealcoating problems
Making your driveway look more attractive through sealcoating may be very harmful for Lake Scugog and its watershed and it may actually harm you and your children who play on it. Studies by the U.S. Geological Survey have identified coal-tar-based sealcoat – the black, viscous liquid sprayed or painted on asphalt pavement such as driveways – as a major source of polycyclic aromatic hydrocarbon (PAH) contamination in lakes and streams near urban areas. Other studies have shown that as much as 50 to 70% of PAH contamination found in the sediment throughout the great Lakes Region can be attributed to coal-tar sealcoat use. PAH concentrations in the coal-tar based sealcoat products are about 1,000 times higher than in an asphalt-based product.
PAH’s are a group of chemical compounds that form whenever anything with a carbon base is burned incompletely, such as wood, gasoline, cigarettes and even meat. They can also be found in objects such as automobile tires and coal tar, whose production involves the heating or of carbon-based materials. Coal tar pitch is the residue remaining following the distillation of coal tar. Coal-tar sealcoat is typically 20 to 35 percent coal-tar pitch.
LAKE SCUGOG
Scientific analysis of sediments running into the lake from some of the stormwater channels done during work in preparation for the Lake Scugog Environmental Management Plan by Kawartha Conservation indicated that there were several test sites that had this type of contamination.
If we are to dredge the bays around Port Perry, PAH contamination of the sediment will make that dredging much more costly since — depending on the determined levels of polycyclic hydrocarbons (PAHs) — the sediment might be considered a contaminated and therefore must be taken to special disposal sites at much greater cost.
Make sure you choose a sealcoat with an asphalt base. Read the product container or contract carefully — if it says “coal tar,” “refined coal tar,” “refined tar,” or refined coal-tar pitch” or similar — do not use it.
RISKS:
The public, especially young children, who live near driveways and parking lots are at a serious risk if coal-tar sealcoating is used. PAHs are toxic, carcinogenic, mutagenic and/or teratogenic (causing birth defects) and dangerous to aquatic life. (U.S. Environmental Protection Agency, 2009) Insects and other small creatures that live in the lake and in our streams are particularly susceptible to PAH contamination, especially those that live in the mud where PAHs tend to accumulate. These life forms are the building blocks and their loss or their contamination causes problems up the food chain. (U.S. Department of the Interior and U.S. Geological Survey, Fact Sheet 2011) Bans against coal-tar sealants have been initiated in many cities across the U.S.
KEY FINDINGS:
- Dust from pavement with coal-tar-based sealcoat has greatly elevated concentrations of PAHs compared to dust from unsealed pavement.
- Coal-tar-based sealcoat is the largest source of PAH contamination to the Great Lakes
- Residences adjacent to parking lots with coal-tar-based sealcoat have PAH concentrations in house dust that are 25 times higher than those in house dust in residence adjacent to parking lots without such sealcoat.
- PAHs move from a sealcoated surface into our environment by many mechanisms: storm runoff, adhesion to tires, wind, foot traffic and volatilization.