Environmental and biological monitoring of benzene exposure in a cohort of Italian taxi drivers.
An integrated approach based on ambient and biological monitoring, the latter including both biomarkers of exposure and susceptibility, was applied to characterize benzene exposure in a group of 37 taxi drivers of the city of Parma (Italy). Airborne benzene concentrations were assessed by 24 h personal sampling and work-shift sampling inside the taxicab using passive samplers (Radiello). Benzene metabolites, trans,trans-muconic acid (t,t-MA) and S-phenylmercapturic acid (S-PMA), and urinary cotinine as biomarker of smoking habits were measured by isotopic dilution liquid chromatography tandem mass spectrometry in both pre-shift (PS) and end-of-shift (EOS) samples. Urinary benzene (U-B) levels were determined by solid-phase microextraction gas chromatography-mass spectrometry in EOS samples. Relevant polymorphisms of microsomal epoxide hydrolase, NAD(P)H:quinone oxidoreductase, glutathione S-transferases M1-1 (GSTM1), T1-1, and A1 were characterized by PCR-based methods. Mean airborne benzene concentration was 5.85 +/- 1.65 microg/m3, as assessed by 24 h personal sampling integrating for work-shift, indoor or general environment activities. Significantly, higher benzene concentrations were detected in the taxicab during the work-shift (7.71 +/- 1.95 microg/m3, p < 0.005). Smokers eliminated significantly higher concentrations of U-B and S-PMA than non-smokers in EOS samples [geometric mean (geometric S.D.): 2.58 (4.23) versus 0.44 (1.79) microg/l for U-B; 3.79 (1.50) versus 2.14 (1.87) microg/gcreat. for S-PMA, p < 0.002]. Within smokers, S-PMA concentrations significantly increased at the end of the work-shift compared to pre-shift values (p < 0.05). t,t-MA showed a similar behaviour, although differences were not significant. In the narrow range examined, no correlation was observed between air benzene concentration and urinary biomarkers. All benzene biomarkers but EOS t,t-MA were correlated with U-cotinine (p < 0.05). GSTM1 polymorphism significantly modulated S-PMA excretion, as subjects bearing the GSTM1pos genotype [3.61 (1.15) microg/gcreat.] excreted significantly higher S-PMA concentrations than GSTM1null subjects [2.19 (1.18) microg/gcreat., p < 0.05].
Manini
Paola
P
Laboratory of Industrial Toxicology, Department of Clinical Medicine, Nephrology and Health Sciences, University of Parma, Via Gramsci 14, 43100 Parma, Italy. paola.manini@unipr.it
De Palma
Giuseppe
G
Andreoli
Roberta
R
Poli
Diana
D
Mozzoni
Paola
P
Folesani
Giuseppina
G
Mutti
Antonio
A
Apostoli
Pietro
P
D000111:Acetylcysteine / Q000031:analogs & derivatives / Q000652:urine; D000328:Adult; D000395:Air Pollutants, Occupational / Q000032:analysis / Q000652:urine*; D001554:Benzene / Q000032:analysis / Q000378:metabolism*; D001555:Benzene Derivatives / Q000032:analysis / Q000652:urine*; D003367:Cotinine / Q000652:urine; D004784:Environmental Monitoring; D004851:Epoxide Hydrolases / Q000235:genetics; D005982:Glutathione Transferase / Q000235:genetics; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D018986:Motor Vehicles; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000235:genetics; D016273:Occupational Exposure / Q000032:analysis*; D011110:Polymorphism, Genetic; D012907:Smoking / Q000378:metabolism; D013011:Sorbic Acid / Q000031:analogs & derivatives / Q000378:metabolism
D000111:Acetylcysteine; D000395:Air Pollutants, Occupational; D001554:Benzene; D001555:Benzene Derivatives; D003367:Cotinine; D004851:Epoxide Hydrolases; D005982:Glutathione Transferase; D016660:NAD(P)H Dehydrogenase (Quinone); D013011:Sorbic Acid; C005939:muconic acid; C053003:S-phenyl-N-acetylcysteine; C447479:NQO1 protein, human; C413545:glutathione S-transferase T1; C484555:GSTA1 protein, human