Exposure to benzene in urban workers: environmental and biological monitoring of traffic police in Rome

Objectives-To evaluate the contribution of traffic fumes to exposure to ben zene in urban workers, an investigation on personal exposure to benzene in traffic police from the city of Rome was carried out. Methods-The study was performed from December 1998 to June 1999. Diffusive Radiello personal samplers were used to measure external exposures to benze ne and alkyl benzenes during the workshift in 139 policemen who controlled medium to high traffic areas and in 63 office police. Moreover, as biomarke rs of internal exposure to benzene, blood benzene, and urinary trans, trans -muconic and S-phenyl mercapturic acids were measured at the beginning and at the end of the workshift in 124 traffic police and 58 office police. Results-Time weighted average (TWA) exposure to benzene was consistently hi gher among traffic police than among indoor workers (geometric mean 6.8 and 3.5 mug/m(3), respectively). Among the traffic police, the distribution of individual exposures was highly asymmetric, skewed toward higher values. M ean ambient benzene concentrations measured by municipal air monitoring sta tions during workshifts of traffic police were generally higher (geometric mean 12.6 mug/m(3)) and did not correlat with personal exposure values. In particular, no association was found between highest personal exposure scor es and environmental benzene concentrations. Among the exposure biomarkers investigated, only blood benzene correlated slightly with on-shift exposure to benzene, but significant increases in both urinary trans, trans-muconic and S-phenylmercapturic acids were found in active smokers compared with n on-smokers, irrespective of their job. Conclusion-The exposure to traffic fumes during working activities in mediu m to high traffic areas in Rome may give a relatively greater contribution to personal exposure to benzene than indoor sources present in confined env ironments. Smoking significantly contributed to internal exposure to benzen e in both indoor and outdoor workers.