Biomarkers of exposure to polycyclic aromatic hydrocarbons and related compounds

Polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs) are widespread carcinogenic compounds that arise from occupational, environmental and dietary sources. The metabolites of PAHs and NPAHs in biological fluids have been investigated as potential biomarkers for assessing human exposure to them, and, particularly, urinary metabolites are the excellent candidates due to the non-invasiveness and convenience of collecting the sample. Here we describe HPLC methods for accurately determining one type of these metabolites, monohydroxy PAHs (OHPAHs). The developed method was applied to the urine samples of non-smoker taxi drivers, traffic police officers and rural villagers of Chiang Mai, Thailand. The results showed higher urinary concentrations of OHPAHs in rural villagers, suggesting the higher respiratory exposure to PAHs contained in smoke from biomass burning. On the other hand, 1-nitropyrene (1-NP) is one of the most abundant NPAHs in diesel exhaust particulate matter (DEP). We also developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determining urinary 1-NP metabolites. 1-NP metabolites were quantified in urine from healthy subjects. 6- and 8-Hydroxy-N-acetyl-1-aminopyrenes (OHNAAPs) and 6- and 8-hydroxy-1-nitropyrenes (OHNPs) were the most abundant 1-NP metabolites in human urine. The presence of OHNAAPs and OHNPs in human urine was demonstrated for the first time.