Influence of cigarette smoking on the excretion of urinary benzene in filling-station attendants

The influence of cigarette smoking on concentrations of urinary benzene, a sensitive and specific biomarker proposed for biological monitoring of exposure to very low doses of benzene, was investigated in 24 filling-station attendants and 31 workers non occupationaily exposed to benzene. Environmental monitoring was performed by personal passive samplers "Radiello®", and a spot urine sample was collected at the end of the work shift, from all subjects, for the determination of urinary benzene. Exposure to benzene resulted significantly higher in filling-station attendants (mean 23.3 ± 17.0 /μglm3; range 4.5-66.3 μg/m3) than in controls (mean 4.6 ± 2.6 /μglm3; range <3-11.5 μglm3), while concentrations of urinary benzene did not show any significant difference between the two groups. Considering all subjects as a single group, it was observed that urinary benzene concentrations were positively correlated with the number of cigarettes smoked during the sampling time (rho=0.38; p=0.047) and with airborne benzene levels (rho=0.32; p=0.019), and negatively correlated with the time elapsed between the last smoked cigarette and urine collecting (rho=-0.40; p=0.045). Multiple regression analysis confirmed the influence of cigarette smoking on urinary benzene concentrations. In conclusion, our study showed the validity of urinary benzene as a biomarker for biological monitoring of exposure to very low doses of benzene, although cigarette smoking determined a prevalent etiological role at the low environmental benzene concentrations observed.