Environmental and urinary reference values as markers of exposure to hydrocarbons in urban areas.

A study using individual dosimetry to evaluate the daily inhaled dose of sixteen aromatic and aliphatic hydrocarbons in three groups of primary school children, living in three Italian towns with 50,000 inhabitants or less, (Treviglio-Lombardy; Poggibonsi-Tuscany; Valenza-Piedmont) is presented. The simultaneous use of two passive samplers (radial diffusion) for each child, for a 24 h period, determined both the indoor and indoor + outdoor environmental reference concentrations. We measured the urinary levels of benzene, toluene, ethylbenzene and xylenes for each child and hence determined the urinary reference values for BTEX. We also considered the possibility of using benzene in urine as a biomarker of environmental exposure of the general population to this xenobiotic. We evaluated how both the environmental and biological measures were influenced by the presence of smokers in the surveyed children's houses. For the group of children living in Poggibonsi, we considered the influence of the living area and the traffic density on environmental concentrations of benzene (indoor and indoor + outdoor).