Prominent U.S. scientist will brief state lawmakers about coal-tar sealant threats
OLYMPIA—State Rep. David Frockt wants Washington to be the first state to ban a type of paving sealant that is packed with high concentrations of toxics called polycyclic aromatic hydrocarbons (PAHs), which are linked to cancer and the destruction of fish and aquatic wildlife.
“Coal-tar sealant runoff is not only poisoning streams, lakes, fish and other aquatic wildlife, it is laced with toxic chemicals that are probable causes of cancer, reduced IQs, and other health problems in people,” said Frock (D-North Seattle). “Safe alternatives are available everywhere, so why should we subject our children, ourselves or our environment to these toxic threats?”
Washington D.C. banned coal-tar sealants in 2009 after liver tumors were found in more than half of the bottom-fish in parts of the Anacostia River where sediments had high levels of PAHs.
On Tuesday, the House Environment Committee will hear startling scientific findings about coal-tar sealants from Peter Van Metre, a scientist with the U.S. Geological Survey (USGS). USGS studies have found that:
- PAH levels in coal-tar sealants are about 1,000 times higher than asphalt-based sealants.
- Coal-tar sealants are the main source of rising PAHs levels in urban lakes—accounting for about half of the PAHs in the sediments of 40 lakes that were studied. The sealants were the source of more than half of the PAH levels in sediments sampled from Lake Washington and Lake Ballinger in Montlake Terrace.
- House dust in apartments next to coal-tar-sealcoated parking lots had PAH levels that were 25 times higher than house dust from apartments near concrete, asphalt, or asphalt-based sealcoat parking lot surfaces.
- PAH-contaminated dust collected from sealcoated driveways had concentrations of highly toxic benzo[a]pyrene that were thousands of times higher than Environmental Protection Agency standards that would trigger a cleanup at a toxic-waste site.
The Centers for Disease Control regards benzo[a]pyrene and a number of PAHs as probable causes of lung, liver and other cancers in people. In 2009, a study done for the National Institutes of Health also found that a mother’s exposure to PAH can lower the IQs of her children.
But much of the growing alarm over the chemicals associated with coal-tar sealants is focused on its threats to fish and aquatic habitats.
“Research has shown that these chemicals kill tadpoles and cause tumors on fish,” explained Mo McBroom, policy director at the Washington Environmental Council.
Last July, a coat of coal-tar sealant that was applied in a rainstorm was washed from the pavement and killed all aquatic life in a 1.5-mile section of Hodges Creek in North Carolina.
Austin, Texas, was the first city to ban coal-tar sealants. The city acted after studies linked the sealants to the loss of species and organisms downstream from sources of parking-lot runoff.
Austin scientists estimate the city’s ban has prevented about one million pounds of PAH from entering the environment since 2006, with low-enforcement costs and no problems with costs or delays for contractors.
A number of private companies have voluntarily removed coal-tar paving sealants from their shelves due to the mounting evidence of their environmental impacts.
“I salute all the voluntary efforts to eliminate coal-tar sealants,” said Frockt. “But a full statewide ban is the only sure way to protect our health and environment from what we’ve learned are very nasty toxic threats.”
House Bill 1721 would ban sales and application of coal-tar paving sealants after Jan. 1, 2012.
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