An integrated approach to evaluate PAH exposure

Introduction - An integrated evaluation of PAH exposure should consider different routes of absorption, reliability and specificity of biomarkers of dose, and individual susceptibility. Material and Methods - The present study investigated the exposure to PAHs in coke oven workers (n=100), asphalt pavers (n=98) and ground construction workers (n=47), by means of environmental exposure and biological monitoring. Results – Personal exposure to total airborne PAHs [from naphtalene to indeno(1,2,3-cd)pyrene] in coke oven workers (median 140 µg/m3), was much higher than in pavers exposed to bitumen fumes (0.6 µg/m3), or in construction workers (0.4 µg/m3),. Urinary 1-hydroxypyrene (1-HOP) in end-shift samples was significantly higher in cokeoven workers (2.2 µg/l) than in asphalt pavers (0.7 µg/l) and in construction workers (0.4 µg/l). An increasing trend in 1-HOP levels, over the workweek and the workshift was registered. A similar trend was observed for urinary 2-hydroxyfluorene (2-FLE) and 3-hydroxyphenanthrene (3-PHE) as well as for some unmetabolised PAH in urine. In smokers with low exposures an important contribution to biomarkers was given by tobacco smoking. PAH-DNA adducts in peripheral blood lymphocytes were not associated with external exposure. Genetic polymorphisms of metabolic and DNA repairing enzymes (CYP1A1, GSTM1, GSTT1, XPD) did not appear to influence the levels of biomarkers. Total dermal contamination of PAHs in pavers, assessed in a subgroup of workers (n=22), ranged from 23 to 623 µg. Significant correlations between dermal phenanthrene or pyrene and 1-HOP (r = 0.41 and 0.55), suggest that dermal exposure significantly contributes to the internal dose of these compounds. Conclusion – Our results suggest that urinary biomarkers of PAHs, integrating exposure from all sources and routes, are reliable tools for risk assessment in occupational health.