Analysis of urinary S-phenylmercapturic acid and trans,trans-muconic acid as exposure biomarkers of benzene in petrochemical and industrial areas of Korea

Objectives Recently, S-phenylmercapturic acid (S-PMA) and trans,trans-mucon ic acid (t,t-MA) in urine have been proposed as reliable biomarkers for mon itoring occupational exposure to benzene. The aim of this study was to test the applicability of S-PMA and t,t-MA as exposure biomarkers and to monito r the occupational exposure level and the extent of environmental contamina tion from benzene in Korea. Methods The urinary excretion of S-PMA and t,t-MA in rats after the intrape ritoneal administration of benzene (0.88 similar to 800 mg/kg body weight, 7 days) was examined. These biomarkers were also validated in human urine s amples collected from elementary schoolchildren in several industrial areas including chemical manufacturing plants, oil refineries, and natural gas-p roducing installations in Korea. Urine was collected from elementary school children in a mountain village with no known occupational exposure to benze ne and air pollution as the reference group. Results In rats, there was a significant relationship between the benzene c oncentration and the excretion of the urinary S-PMA and t,t-MA as a functio n of concentration, and the excretion of benzene metabolites peaked on the first day after intraperitoneal administration. In human urine, higher leve ls of S-PMA and t,t-MA were detected more frequently in petrochemical indus trial areas than in areas with no known occupational exposure to benzene. Conclusions These results show that the quantitative determination of S-PMA and t,t-MA in urine can be used as a reliable exposure biomarker for benze ne, and they also suggest that extensive attention to benzene exposure is n eeded for maintaining the health of the population in Korea.