GENETIC-EFFECTS OF PETROLEUM FUELS - CYTOGENETIC MONITORING OF GASOLINE STATION ATTENDANTS

Workers in the petroleum distribution trades experience relatively hig h-level exposures to fuel vapours whose consequences have not been ful ly elucidated. In this study, the possible relationship between occupa tional exposure to petroleum fuels and cytogenetic damages in peripher al lymphocytes was investigated. Twenty-three male, non-smoking worker s from the area of Pome were enrolled in the study, together with age- paired controls with no occupational exposure to fuels. Peripheral lym phocyte cultures were set up for the analysis of structural chromosome aberrations (CAs), sister chromatid exchanges (SCEs) and micronuclei (MN) in cytokinesis-blocked lymphocytes. Frequencies of CAs, SCEs and MN were compared between exposed and control groups, and evaluated in relation to blood lead level (as an indicator of engine exhausts expos ure) for the whole group under study, and to yearly averaged exposure to benzene (8-h time weighted averages, as determined by repeated pers onal sampling) for fillingstation attendants only. Both CAs and SCEs w ere slightly increased in station attendants: 1.97 versus 1.46 aberrat ions per 100 cells, and 4.73+/-0.15 versus 4.48+/-0.11 SCEs/cell in ex posed and control individuals, respectively. The difference between cu mulative CA rates in the exposed and control populations was of border line statistical significance (p = 0.066). However, when the exposed p opulation was dichotomized for benzene exposure, a significant(p = 0.0 18) correlation of CAs with benzene exposure was found. The analysis o f SCE data highlighted a significant increase of cells with more than 6 exchanges (HFCs), corresponding to the 75 degrees percentile of the overall distribution, in fillingstation attendants (relative risk (RR) = 1.3, 95% CI = 1.1-1.5) in comparison with controls. In the pooled po pulation, the frequency of HFCs showed a statistically significant upw ard trend at increasing blood lead levels (chi(2) for trend = 27.8, p < 0.0001). A complex relationship between SCEs and benzene exposure wa s observed, with an increased frequency of HFCs in the medium exposure intensity class (RR = 1.5, 95% CI = 1.2-1.7), and no difference for e xposure to higher benzene levels (RR = 1.0, 95% CI = 0.9-1.2), compare d to reference subjects. Finally, the analysis of MN in both phytohema gglutinin- and pokeweed-stimulated cell cultures did not show signific ant excess of MN in binucleated lymphocytes of exposed workers with re spect to the age-paired controls.