Exposure to polycyclic aromatic hydrocarbons (PAH) in roofers : an Italian multicentric study

Introduction: Among various chemical agents present at the workplaces in the roofing activity, a particular attention was addressed to the Polycyclic Aromatic Hydrocarbons (PAH) contained in bituminous membrane, but some questions regarding level of exposure are also controversially discussed. The literature reports that PAH may have irritant effects; moreover, some of these have been recognized as probably or possibly carcinogenic to human by the International Agency for Research on Cancer, the European Union, and other institutions. During last two years, a study aimed to evaluate the PAH occupational exposure in 51 roofers in Lombardy, Italy was planned. Methods: The protocol included interview via questionnaires, environmental air monitoring (active personal sampling during the work shift), and biological monitoring (determination of 1-hydroxypyrene and unmetabolized compounds in urine spot samples collected three at different moments: baseline after two days of vacation, before shift and at end shift on a day in the second half of the week). Analysis of the most relevant PAH, according to the American Environmental Protection Agency, EPA, was performed by High Performance Liquid Chromatography (HPLC) by fluorimetric detector. Results: Median airborne levels of PAH ranged from 229 to below 0.03 ng/m3. Particle-phase PAH was low (i.e. median Benzo(a)pyrene 1 ng/m3) and significantly lower than vapour-phase. Excretion of urinary 1-hydroxypyrene (expressed by ng/g creatinine) showed a significant increase at different sampling moments in roofers, smokers, and non-smokers: baseline was lower than at the beginning of the workshift, and values were even higher in the end workshift sample (median values 227, 294, and 349, respectively). Discussion: The results of this study demonstrate that roofers experience slight occupational exposure to PAH, resulting in a significant increase of urinary 1-hydroxypyrene during the workweek. The PAH exposure showed in these workers is generally not higher than that observed in other study regarding low-level exposure.