Urinary polycyclic aromatic hydrocarbons as biomarkers of exposure to carcinogens

Introduction: Some polycyclic aromatic hydrocarbons (PAHs), among which naphthalene, chrysene, benzo[a]anthracene, benzo[a]pyrene, are classified as carcinogenic to humans. For this reason, an interest exists in assessing exposure to these compounds. Urinary 1-hydroxypyrene (1-OHPYR), a metabolite of pyrene, is widely used as biomarker of exposure to PAHs, but it lacks of specificity. Aim of the present study was to investigate the use of urinary unmetabolized PAHs (U-PAHs) as specific biomarkers of exposure to carcinogenic PAHs. Methods: Urine spot samples were collected from fifty-five male Polish coke oven workers, all smokers, at the end of the workshift. U-PAHs (naphthalene, acenaphtylene, acenaphthene, fluorene, phenanthrene, anthracene, fluorantene, pyrene, benzo[a]anthracene, chrysene, benzo[k]fluoranthene, benzo[b]fluoranthene, benzo[a]pyrene) were determined by automatic solid phase micro-extraction followed by gas chromatography/mass spectrometry. 1-OHPYR was also determined. Results: U-PAHs from naphthalene to pyrene were found in 100% of the samples, benzo[a]anthracene and chrysene in 96%, while benzo[k]fluoranthene, benzo[b]fluoranthene and benzo[a]pyrene were present in 7, 13 and 22% of the samples. Median naphthalene, chrysene, and benzo[a]anthracene were 0.806, 0.032 and 0.035 µg/L, while 1-hydroxypyrene was 15.4 µg/L. Significant correlations were found between values of U-PAHs (0.33<Pearson’s r<0.93, p<0.01) and between U-PAHs and 1-OHPYR (0.38<r<0.77, p<0.01). In particular, naphthalene, benzo[a]anthracene and chrysene were correlated with 1-OHPYR (r=0.74, 0.77, 0.40, p<0.01). Discussion: For the first time, urinary benzo[a]anthracene and chrysene were quantified in occupationally exposed subjects. Their correlations with 1-OHPYR show that these analytes are reliable biomarker of PAHs internal dose. The results of this study support the use of U-PAHs as specific biomarkers of exposure to carcinogenic PAHs.