Urinary t,t-muconic acid, S-phenylmercapturic acid and benzene as biomarkers of low benzene exposure

Abstract This research compared the capability of urinary trans , trans -muconic acid ( t , t -MA), S -phenylmercapturic acid ( S -PMA) and benzene excreted in urine (U-benzene) to monitor low benzene exposure and evaluated the influence of smoking habit on these indices. Gasoline attendants, urban policemen, bus drivers and two groups of referents working in two large Italian cities (415 people) were studied. Median benzene exposure was 61, 22, 21, 9 and 6 μg/m 3 , respectively, with higher levels in workers than in referents. U-benzene, but not t , t -MA and S -PMA, showed an exposure-related increase. All the biomarkers were strongly influenced by cigarette smoking, with values up to five-fold higher in smokers compared to non-smokers. In conclusion, in the range of investigated benzene exposure ( 3 or