Influence of glutathione S-transferases polymorphisms on biological monitoring of exposure to low doses of benzene.

The monitoring of benzene exposure is crucial to prevent the toxic effects of the solvent. In this view, a cohort of 28 petrochemical workers (6 smokers and 22 no smokers) was monitored throughout ten consecutive days collecting 174 environmental ad biological samples. Airborne benzene, t,t-transmuconic acid, S-phenylmercapturic acid (S-PMA), and glutathione S-transferase (GST) genotype (M1 and T1) were measured. S-PMA was the only metabolite well related to airborne benzene (r= 0.447, p< 0.0001), above all if workers were no smokers (r= 0.667, p<0.0001), being the smoking habit the only variable influencing metabolite excretion. On the other hand, a reduced S-PMA excretion was observed according to GSTT1 null genotype only. In conclusion, the results show that under low benzene concentration exposure only S-PMA is able to monitor the exposure and that GSTT1 null genotype has low but significance influence on the metabolite excretion. The influence of GSTT1 null genotype is low, even if studying each subject with several samples, the presence of almost one null genotype ameliorates the correlation between airborne benzene and S-PMA excretion.