Interpretation of Biomarkers for Exposure to Polycyclic Aromatic Hydrocarbons (PAH)

Polycyclic aromatic hydrocarbons (PAH) are ubiquitous environmental pollutants that pose a complex health hazard which includes carcinogenicity, reproductive toxicity, and immunotoxicity. For the proper risk assessment and risk management of exposure to PAH, appropriate assessment and measurement of exposures is essential.   In most occupational settings exposure to PAH occurs primary by inhalation although dermal exposure may play a significant role in some situations as well. In environmental settings oral (mainly through the diet) and dermal exposure may be equally or even more important than inhalation in the total exposure. Consequently, human biomonitoring of exposure to PAH, which integrates all routes of exposure, has proven to be highly useful in both occupational and environmental settings.   Several biomarkers of PAH exposure have been developed over the past decades. The suitability of biomarkers in human health risk assessment can be based on four criteria: 1. integrity of the sampling methods and subsequent analysis, 2. knowledge of toxicokinetics, which pertains to the ability to describe exposure, 3. knowledge of health effects, which includes dose-response-relationships, and 4. the overall weight-of-evidence and plausibility of hypotheses.   The currently available urinary biomarkers of exposure (3-hydroxy¬benzo[a]pyrene, several hydroxy¬phenanthrenes, and 1-hydroxypyrene) and biomarkers of effective dose (protein and DNA adducts of PAH) were assessed against these four criteria.   Overall it may be concluded that, at present, 1-hydroxypyrene is the most suitable biomarker in the risk assessment of PAH.