Exposure to benzene and toluene of gasoline station workers in Khon Kaen, Thailand and adverse effects

Abstract

This cross-sectional study aimed to assess the adverse effects of benzene and toluene exposure in gasoline station workers via biological screening and health risk assessment. Ambient air benzene and toluene concentrations were monitored and analyzed by gas chromatography (GC-FID). Urinary samples to test trans,trans-muconic acid (tt-MA) and hippuric acid levels were collected after shift work from 158 refueling workers and 34 cashiers; any adverse symptoms were noted in the interview and hazard index (HI) values were estimated for workers’ adverse effects. There was a significant correlation between benzene and toluene concentrations at gasoline stations (r = 0.827). The levels of detected tt-MA and hippuric acid, metabolites of benzene and toluene, respectively, were higher in refueling workers (IQR = 537.88 µg/g creatinine (Cr), 316.41 mg/g Cr) than in cashiers (IQR = 208.68 µg/g Cr, 236.17 mg/g Cr). The concentrations of benzene and locations of stations were associated with detection of tt-MA. Adverse symptoms of benzene and toluene exposure, i.e., sore throat, drowsiness, muscle weakness, and unconsciousness were reported. The hazard index values from exposure to benzene and toluene among refueling workers were found to have statistical significance. The conclusion is that carrying out health surveillance with benzene exposure monitoring and health screening can be an important aspect of a strategy to reduce toluene exposure in gasoline workers.