06 Dec 2010:
Coal-based Pavement Sealant
Is Leading Source of Toxin in U.S. Lakes
A coal-based sealant sprayed on pavement for parking lots, playgrounds, and driveways is the leading contributor of a toxic pollutant found in U.S. lakes and reservoirs
, according to a new study. Samples of sediments collected from the bottom of lakes and reservoirs in 40 urban areas by the U.S. Geological Survey revealed high levels of polycyclic aromatic hydrocarbons (PAHs), a probable carcinogen that is also toxic to fish and other marine life. On average, about half of the PAHs came from coal-tar sealants. Vehicles account for about one-fourth of the remaining pollutants, and coal combustion contributes about 20 percent, according to the study, published in the journal Science of the Total Environment
. Coal-tar pavement sealants — derived from the waste produced in the coking of steel — have been banned in several U.S. cities, including Austin, Texas, and Washington, D.C. An alternate asphalt-based sealant contains levels of PAHs that are 1,000 times lower than coal-tar sealants
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A look at how acidifying oceans could threaten the Dungeness crab, one of the most valuable fisheries on the U.S. West Coast. Watch the video.
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An aerial view of why Europe’s per capita carbon emissions are less than 50 percent of those in the U.S. View the photos.
An indigenous tribe’s deadly fight to save its ancestral land in the Amazon rainforest from logging. Learn more.
video series looks at the staggering amount of food wasted in the U.S. – a problem with major human and environmental costs. Watch the video.
Residents of the Chocó Rainforest in Ecuador are choosing to plant cacao over logging in an effort to slow deforestation.
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Tribal people and ranchers join together to stop a project that would haul coal across their Montana land. Watch the video.