Analysis of Benzene Exposure in Gas Station Workers Using Trans,Trans-Muconic Acid

In Brazil, gas station workers are occupationally exposed to the benzene present in gasoline. Brazilian law indicates the use of trans,trans-muconic acid(t,t-MA) as a biomarker of benzene exposure. The aim of this study was to evaluate the level of exposure to benzene in gas station workers, through the quantification of t,t-MA present in urine. A total number of 269 gas station workers divided into 179 filling station attendants exposed by inhalation and dermal route and 90 convenience store workers exposed only by inhalation were included. A control group was formed by 100 office workers, without occupational exposure to benzene. The urinary levels of t,t-MA were evaluated by HPLC with a UV detector. Gas station workers showed higher mean values of t,t-MA (0.204 mg/g creatinine; 95% CI 0.170-0.237) than office workers (0.126 mg/g creatinine; 95% CI 0.0817-0.1693). T,t-MA levels were higher in convenience store workers exposed to gasoline only by inhalation (0.221 mg/g creatinine; 95% CI 0.160-0.282), than in those exposed to gasoline by inhalation and dermal route-filling station attendants (0.195 mg/g creatinine; 95% CI 0.155-0.235). Gas station workers with a higher level of t,t-MA had epistaxis. T,t-MA values were higher in the Downtown (0.15 mg/g creatinine) region's workers than in the more affluent South Zone region's workers (0.07 mg/g creatinine). Smoking habits influenced the urinary t,t-MA values, while the frequency of consumption of industrialized and frozen foods showed no influence.