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Objectives-To evaluate the contribution of traYc fumes to exposure to benzene in urban workers, an investigation on personal exposure to benzene in traYc police from the city of Rome was carried out. Methods-The study was performed from December 1998 to June 1999. DiVusive Radiello personal samplers were used to measure external exposures to benzene and alkyl benzenes during the workshift in 139 policemen who controlled medium to high traYc areas and in 63 oYce police. Moreover, as biomarkers 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 traYc police and 58 oYce police. Results-Time weighted average (TWA) exposure to benzene was consistently higher among traYc police than among indoor workers (geometric mean 6.8 and 3.5 µg/m 3 , respectively). Among the traYc police, the distribution of individual exposures was highly asymmetric, skewed toward higher values. Mean ambient benzene concentrations measured by municipal air monitoring stations during workshifts of traYc police were generally higher (geometric mean 12.6 µg/m 3 ) and did not correlat with personal exposure values. In particular, no association was found between highest personal exposure scores 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 nonsmokers, irrespective of their job. Conclusion-The exposure to traYc fumes during working activities in medium to high traYc areas in Rome may give a relatively greater contribution to personal exposure to benzene than indoor sources present in confined environments. Smoking significantly contributed to internal exposure to benzene in both indoor and outdoor workers. (Occup Environ Med 2001;58:165-171)

Objectives-Benzene is an established animal and human carcinogen. The mechanism of benzene toxicity, particularly its leukaemogenic effect, is not fully understood. The modified base 8-hydroxydeoxyguanosine (8-OHdG) is a sensitive marker of the DNA damage due to hydroxyl radical attack at the C8 of guanine. This damage, if left unrepaired, has been proposed to contribute to mutagenicity and cancer promotion. We conducted this biomonitoring study with the aim of evaluating the association between excretion of 8-OHdG and level of exposure to benzene and other aromatic compounds among occupationally exposed people. Methods-A random sample of 65 filling station attendants from Rome, Italy was studied for personal exposure to benzene, toluene, and xylenes, and excretion of 8-OHdG. Information about age, length of employment, smoking habits, and diagnostic exposure to x rays was collected by questionnaire. An average yearly level of exposure to benzene and methylbenzenes was calculated for each filling station attendant on the basis of about seven repeated personal samples collected during one year. A spot sample of 20 ml of urine was collected from each worker. Concentrations of 8-OHdG were determined by high performance liquid chromatography (HPLC) with coupled columns. Results-A mean (SD) concentration of 1-36 (0.49) umol of 8-OHdG/mol of creatinine was measured. A significant correlation was found between urinary 8-OHdG and exposure to benzene (r =

A molecular epidemiological study on Roman policemen is ongoing. The results of a first assessment of the occupational exposure to aromatic compounds of 66 subjects engaged in traffic control and of 33 office workers are presented in this paper. Passive personal samplers and urinary biomarkers were used to assess exposure to benzene and polycyclic hydrocarbons during work shifts. The results obtained indicate that benzene exposure in outdoor workers is about twice as high as in office workers (geometric mean 7.5 and 3.4 micrograms/m3, respectively). The distribution of individual exposure values was asymmetrical and skewed toward higher values, especially among traffic wardens. Environmental benzene levels recorded by municipal monitoring stations during work shifts (geometric mean 11.2 micrograms/m3) were in the first instance comparable to or greater than individual exposure values. However, several outlier values were observed among personal data that greatly exceeded average environmental benzene concentrations. Among the exposure biomarkers investigated, only blood benzene correlated to some extent with previous exposure to benzene, while a seasonal variation in the excretion of 1-hydroxypyrene and trans-muconic acid was observed in both study groups. In conclusion, these results suggest that outdoor work gives a greater contribution than indoor activities to benzene exposure of Roman citizens. Moreover, relatively high-level exposures can be experienced by outdoor workers, even in the absence of large-scale pollution episodes.

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