Assessment of exposure to Polycyclic Aromatic Hydrocarbons (PAH) in Italian asphalt workers

Objectives: Purpose of the work was the assessment of exposure to Polycyclic Aromatic Hydrocarbons (PAH), a family of ubiquitous pollutants some of which are carcinogens, in 100 Italian asphalt workers (exposed to bitumen fumes and diesel exhausts) and in 47 ground construction operators (exposed only to diesel exhausts). Methods: The protocol included interview by questionnaires, environmental air-monitoring (active personal sampling during the work shift), dermal contamination measures (six polypropylene pads), and biological monitoring (urine collected in three different moments: baseline after two days of vacation, before shift and at the end of shift on a day of the second half of the week). The analysis of the most relevant PAH, according to the American Environmental Protection Agency, EPA, was performed by High Performance Liquid Chromatography (HPLC) with fluorimetric detector. Results: Median airborne levels of PAH ranged from 408 to below 0.07 ng/m3. Among different work-tasks and versus the confronted group (ground construction operators), there were not statistically significant differences in air-environmental exposure. Excretion of urinary 1-hydroxypyrene showed a significant increase among different sampling moments in asphalt workers, smokers and non-smokers: baseline lower than the beginning of the workshift, with the higher values at the end of the workshift. Comparing the two groups, a significant difference in the levels of metabolite not appears, whereas this trend can be viewed observing the non-smokers. The results show that the dermal contamination in asphalt workers is significantly higher than in ground construction operators and that in asphalt mixing employees are lower than the other activity. We did not found important differences in dose density between pads located on different body region. Cutaneous dose rate is about threefold higher than airborne dose rate, whereas considering the toxicokinetical information (Kp, lag time, experimental dermal absorption data) and the hygienistic data (particle size of bitumen fume), the relevance of dermal absorption is lower than respiratory one. Conclusions: The results of this study demonstrate that asphalt road pavers experience a moderate occupational exposure to airborne PAH, resulting in a significant increase of urinary 1-hydroxypyrene during the workweek.