Urinary 2-hydroxyfluorene and 1-hydroxypyrene levels in smokers and nonsmokers in Japan and Thailand

2-Hydroxyfluorene (2-OHF) and 1-hydroxypyrene (1-OHP) in urine samples of smokers and nonsmokers were determined separately by using two high-performance liquid chromatography (HPLC) systems with fluorescence detection. Urine samples were collected from the subjects who lived in Japan and Thailand, and were not occupationally exposed to polycyclic aromatic hydrocarbons (PAHs). The mean concentrations of 2-OHF and 1-OHP of Thai smokers (0.75 and 3.03 mumol/mol creatinine) and nonsmokers (0.22 and 0.91 mumol/mol creatinine) were both higher than those of Japanese smokers (0.26 and 0.12 mumol/mol creatinine) and nonsmokers (0.04 and 0.06 mumol/mol creatinine), respectively. The difference between smokers and nonsmokers was more significant for 2-OHF than for 1-OHP reflecting the higher intake of fluorene in the vapor phase by the smoking. Moreover the higher urinary levels of both 2-OHF and 1-OHP were observed in Thai nonsmokers than those in Japanese nonsmokers, suggesting the higher background exposure to PAHs of Thai subjects.