Levels of OH-PAHs and markers of oxidative stress in urine of taxi drivers and controls

Polycyclic aromatic hydrocarbons are pervasive in the atmosphere, originating from sources like vehicle emissions and incomplete combustion. Exposure to PAHs occurs through diet, tobacco smoke, and air pollutants, and they are recognized as carcinogens. This study, conducted from July to October 2021 in Seoul, Gyeonggi, and Ulsan regions, focused on taxi drivers, a group with elevated PAH exposure due to prolonged vehicle use. The study involved 19 male taxi drivers and 46 control participants (18 male, 28 female). LC-MS/MS analysis was employed to quantify urinary levels of 18 hydroxy-PAHs, oxidative damage markers (MDA, 8-OHdG), and cotinine. The detection rates of OH-PAHs were 1-naphthol (96.9 %), 2-naphthol (90.8 %), 2-hydroxyfluorene (86.2 %), and 1-hydroxypyrene (80.0 %). Compared to the male controls, taxi drivers showed higher median concentrations of 2-OH-Na (1.698 ng/mL), 1-OH-Na (0.666 ng/mL), 2-OH-Flu (0.067 ng/mL), and 1-OHP (0.045 ng/mL). Similarly, significant differences were observed between taxi drivers and female controls for 1-OH-Na, 2-OH-Na, 2-OH-Flu, 3-OH-Phe, and 1-OHP. MDA and 8-OHdG were detected in over 90% of all groups, with significant differences between taxi drivers. Strong positive correlations were revealed between urinary OH-PAHs, MDA, and 8-OHdG (r ranging from 0.589 to 0.770, p<0.01). The findings suggest that taxi drivers, due to prolonged exposure to traffic-related air pollutants, have elevated levels of PAH metabolites and oxidative stress, especially among smokers. Further studies with larger sample sizes are recommended to validate these results and explore the long-term health implications of occupational PAH exposure in urban transportation workers..