Assessment of the Pulmonary Genotoxicity of Bitumen Fumes in Big Blue® Transgenic Rats

Occupational and environmental exposures to bitumen fumes during road paving or roofing activities represent a safety issue since this complex mixture of volatile compounds and particles contains carcinogenic polycyclic aromatic hydrocarbons (PAH). However, epidemiological and experimental animal studies failed to draw unambiguous conclusions concerning bitumen fumes toxicity. In order to gain better insights on their genotoxic potential, we used an experimental device able to generate bitumen fumes at 170°C (upper range used during road paving operations) with a total particulate matter of 112 ± 13 mg/m3 and a mass median aerodynamic diameter of 4.6 μ m. The nose-only exposure of Big Blue® transgenic rats was performed 6 h/day for 5 consecutive days. Biological exposure to this aerosol was monitored by measuring the rat urinary levels of 1-hydroxypyrene and lungs were collected at various time-points after the end of treatment for further analysis. As determined by the 32P post-labeling method, no DNA bu...