Exposure to air pollution in general population living in urban and rural environment: urinary benzene as biological index of exposure

Evidence is needed regarding air pollutant exposure in general population. One of the most important contributors to air urban pollution is benzene, a widespread air pollutant present both in outdoor and indoor environments, and a well known human carcinogen. The aim of our study was to investigate the use of urinary (u) unmodified benzene (UB) as a biomarker of air environmental pollution for general population. u-UB and u-cotinine were measured in urine samples of 243 Italian children (5-11 years) recruited in a cross-sectional study. Urine samples were collected at the end of the day, an analytical determination of benzene was performed by solid-phase micro-extraction (SPME) - GC/MS. Analytical results were compared with data obtained from questionnaires about participants' main potential exposure factors. The main findings were that u-UB levels were influenced by secondhand smoke (SHS) exposure and urbanization of residence areas. In addition, data showed that, excluding children exposed to SHS, u-UB concentrations were about 2-fold higher in subjects living in urban areas than in those in the rural environment (medians=210.50 and 92.50 ng/L, respectively). These results were confirmed by multivariate linear regression model. In conclusion, we found that u-UB is a good biomarker of benzene exposure in general population. In addition, u-UB could be considered as a synthetic biological index for the assessment of population exposure to atmospheric pollution.