Biomatrix of health risk assessment of benzene‐exposed workers at Thai gasoline stations

OBJECTIVE: This study assessed the health risk of benzene exposure among Thai gasoline station workers through biomarker detection and experience of adverse symptoms. METHODS: Trans, trans‐muconic acid (tt‐MA) metabolites of benzene were analyzed from spot urine sampled among gasoline station workers after shift work using HPLC‐UV. Air benzene monitoring was done with an active sampler connected to a charcoal sorbent tube, and analyzed by GC‐FID. The health risk was calculated by using the biomatrix of the likelihood of benzene exposure and the severity of adverse symptoms. RESULTS: The tt‐MA concentration, among 235 workers, ranged from less than 10–2159 µg/g Cr, which corresponded to the air benzene concentration range of <0.1 to 65.8 ppb. In total, 32.3% of workers had a higher than acceptable risk level and there was a significant association between gasoline station work zones and the likelihood of benzene exposure as well as the health risk of workers. The health risk levels estimated from the biomarker monitoring were consistent with the risk matrix of air benzene monitoring. CONCLUSION: This tt‐MA biomarker monitoring and biomatrix of health risk assessment is suggested as useful for health surveillance of gasoline station workers exposed to benzene.