Roofers and road construction workers who use hot asphalt are exposed to high levels of polycyclic aromatic hydrocarbons (PAHs), according to research from the Cancer Center at the University of Colorado School of Public Health. The study shows that roofers have higher PAH blood-levels after working a shift, and that these high levels of PAHs are linked with increased rates of DNA damage, and potentially with higher cancer risk.
“We’ve known for some time that roofers and road workers have higher cancer rates than the general population, but we also know roofers have a higher rate of smoking, alcohol use, and higher UV exposure than the general population. It’s been difficult to pinpoint the cause of higher cancer rates – is it due to higher PAHs or is it due to lifestyle and other risk factors?” says Dr. Berrin Serdar, investigator at the Cancer Center and assistant professor of environmental and occupational health at Colorado.
Her study, completed with colleagues at the University of Miami, studied 19 roofers from four work sites in Miami-Dade County. Participants’ urine samples provided before and after a 6-hour shift, showed that after acute exposure to hot asphalt PAH biomarkers were elevated. Overall, biomarkers of PAH exposure and oxidative DNA damage (8-OHdG) were highest among workers who did not use protective gloves and workers who also reported work related skin burns, pointing to the role of PAH absorption through skin.
“PAHs are a complex mixture of chemicals some of which are known human carcinogens. They are produced by incomplete combustion of organic materials and exist in tobacco smoke, engine exhaust, or can come from environmental sources like forest fires, but the highest exposure is among occupational groups, for example coke oven workers or workers who use hot asphalt,” Dr. Serdar says.