BTEX exposure and metabolite levels in Taiwan schoolchildren near petrochemical areas

Introduction: Benzene, toluene, ethylbenzene, and xylenes (BTEX) in ambient air pose significant health risks for residents near petrochemical facilities. However, limited research has investigated the correlation between BTEX exposure and urinary metabolites in children. This is the first study to determine this association among primary school children near petrochemical industrial parks (PIPs) in Taiwan. Methods: Between October 2019 and December 2020, 1295 children from 20 primary schools near PIPs were recruited. Morning midstream urine samples were collected, and urinary BTEX metabolites concentrations were analyzed using isotope dilution and modified liquid chromatography-tandem mass spectrometry (LC-MS/MS). Ambient BTEX at the schools was measured using 6-L stainless-steel canisters over three consecutive days before urine collection, following US EPA Method TO-15. Multivariate linear regression was employed to assess the relationship between ambient BTEX and urinary metabolites. Results: The mean ambient BTEX concentrations were 0.44, 5.17, 0.21, and 0.75 ppb, respectively. Geometric mean urinary concentrations of S-phenyl mercapturic acid (SPMA), benzyl mercapturic acid (BMA), phenyl glyoxylic acid (PGA), and methyl hippuric acids (MHAs) were 0.18, 6.63, 214.01, and 178.33 μg/g creatinine, respectively. Children within 1 km of PIPs exhibited significantly higher SPMA (0.21 μg/g creatinine) and BMA (6.67 μg/g creatinine) levels. A positive correlation was observed between ambient benzene levels and urinary SPMA (beta = 0.19, p = 0.017). Conclusions: The study reveals that children attending schools within 1 km of PIPs face higher benzene exposure. This comprehensive research highlights elevated BTEX levels and urinary metabolites, emphasizing the need for monitoring and safeguarding vulnerable children.