A Texas study found a coating used in many parking lots may be a major source of potentially harmful polycyclic aromatic hydrocarbons.
PAHs are produced by the incomplete burning of organic substances, including coal, oil, wood, tobacco and even meat. They have been linked to tumors, reproductive difficulties and other health problems in animals and humans.
The U.S. Geological Survey and City of Austin found PAH levels in runoff from parking lots where coal-tar sealcoat was used were 65 times those in lots where there was no sealcoat.
The research was reported in the on-line edition of the American Chemical Society's journal Environmental Science and Technology.
Other sources of PAHs in the environment include tobacco smoke, industrial and auto pollution and leakage from toxic waste sites.
Copyright 2005 by United Press International
Explore further: 'Here comes the sun': Does pop music have a 'rhythm of the rain?'