The new coal-tar pavement or sealant that is laid on a driveway, street, parking or playground lot is something you’ve probably smelled many times. We have all wondered about the toxicity of the horrible smelling stuff. It is toxic as it contains polycyclic aromatic hydrocarbons (PAHs). A study recently released by the U.S. Geological Survey (USGS) and Milwaukee Metropolitan Sewerage District have identified coal-tar sealants as the primary source of PAHs and called a major source of contamination in urban and suburban areas as well as a potential concern for human health and aquatic life. And considering this awful finding…what about the risks for CANCER as well!
When toxic coal-tar sealants were found to be responsible for up to 94% of the PAHs found in 40 samples of streambed sediment, or muck, collected from 19 creeks and rivers with dust from six parking lots in metropolitan Milwaukee, it finally made the headlines.
Austin Baldwin, lead study author and USGS scientists reported that 78% of the samples contained enough PAHs to be considered toxic and capable of causing adverse effects in aquatic animals. PAHs and contaminants from sealed and blacktopped surfaces wash into stormwater storage basins and sewers from rain and melting snow, and washed right into the closest waterways, poisoning them.
Sealants used for paving in commercial, residential and industrial areas contain up to 1,000X more PAHs than asphalt emulsions that do a comparable job but cost more. Both the sale and use of coal-tar sealants were banned as far back as 2007 in Dane County, Wisconsin. Before that cut-off 300,000 gallons of the stuff were used every year on driveways and parking lots in that county alone.
Finding PAHs in the water is not an isolated or new problem. In Minneapolis-St. Paul area it is believed that it will reach a cost of $1 billion to clean up PAH problems in stormwater ponds. The PAHs in area streams were worse in 2013 for aquatic life than any other chemicals. There are projects to restore the salmon’s habitations, but many died before they could spawn, right after rainstorms, including 90% of the females in a waterway called Longfellow Creek.
These toxic materials, right up close and personal, are not anything new. In April of 1887, a 27-year-old man was committed to Hudson River State Hospital for the insane and less than two weeks later, another man was in a similar condition. When a 3rd man showed up, it was found they all worked at the same rubber factory and an investigation ensued. They all exhibited bizarre, incoherent and erratic behavior caused from carbon disulfide, a solvent in manipulating PAH materials.
Carbon disulfide has a history of manufacturing and testicular hysteria. As far back as 1856, a researcher noted that everything from weird dreams to memory gaps, and premature aging abolished sexual desire. Many of these victims actually worked in condom factories. These illnesses were associated with hysteria that were usually women, but more than 60 case histories of male hysterics were logged in Paris in the 1880’s. It is still a problem and compromises Federal standards. Many states still spread roads with brine from oil and gas operations, believing it’s a safe way to recycle it. The wastewater is tainted with chloride as well as radium and barium, which are radioactive.
Salt on roadways is toxic to humans and animal life. Scientists have had a bad feeling about the potential of toxins from run-off for a long time, but the salmon study finally opened a door that would allow them to help fix it. They intend to use a simple, soil-based filtration system. Others are using free cheese brine, sugarcane molasses and beet juice, mixed in with road salt to act as alternate de-icing agents. Let the Earth do what it does so well, what it has done for eons: clean things up!
Dr Fredda Branyon