The Relations between Polycyclic Aromatic Hydrocarbons Exposure and 1-OHP Levels as a Biomarker of the Exposure

Background and aim: Polycyclic aromatic hydrocarbons (PAHs) are the products of incomplete combustion or pyrolysis of various organic materials. Their ubiquity in the environment leads to measurable levels of exposure. However, the exposure varies strongly between different regions in Europe. Some PAHs with four or more rings are suspected to be human carcinogens. Therefore, the occupational and/or environmental exposure to PAHs may cause a significant health risk. The aim of the study was to evaluate current levels of PAH exposure in defined groups of workers.

Methods: The industrial sites selected in this survey involved PAHs originating from coal tar pitch, carbon black, bitumen, and rubber fumes. Based on the historical data, the sites were expected to exhibit quantifiable levels of exposure to PAHs. The total study population consisted of 139 persons: 108 workers (85 males and 23 females) workers were occupationally exposed in aluminium production, the production of graphite electrodes, road construction, or the rubber forming industry and 31 control individuals in two groups.

Results: The highest concentrations – 8-hour time-weighted average (TWA) levels (sum of 16 components according to the EPA list), as expected, were found in the aluminium production plant (55.15 µg.m⁻³) and production of graphite electrodes (54.25 µg.m⁻³). The lowest concentrations were found in personal air samples of road construction workers (1.93 µg.m⁻³). The concentrations of 1-hydroxypyrene as a pyrene metabolite (1-OHP) in the urine of the exposed group of workers were found in levels 0.74 µmol.mol⁻¹ creatinine before the exposure and 2.27 µmol.mol⁻¹ creatinine after the exposure (arithmetic mean values). 1-OHP concentrations in post-shift urine samples were highly correlated with the total airborne PAHs concentrations and pyrene concentrations in air. The correlation coefficients (r_S) between 1-OHP concentration and pyrene or total PAHs in air were 0.710 and 0.752 (p < 0.05). This statistical analysis confirmed the effect of the occupational exposure to PAHs and pyrene on body burden in workers. However, a modifying effect of gender, smoking habits, dietary intake, genetically modified metabolism, and the use of medication on the toxicokinetics of pyrene was not determined as significant.

Conclusion: Based on the results a strong correlation between the concentration of 1-OHP in urine as an exposure biomarker and the concentration of pyrene or PAH was affirmed.