Association between urinary metabolites of 1,3-butadiene and toluene exposure with kidney function indices in Taiwanese school-aged children living near a petrochemical complex

Children residing near petrochemical complexes are vulnerable to chemical exposure and pose risks to pediatric health. This study investigated the associations between urinary metabolites of hazardous compounds and renal function, in 312 individuals aged 6.1-12.5 years from the Taiwan Petrochemical Complex Cohort for Children. We used ultra-high-performance liquid chromatography combined with tandem mass spectrometry to evaluate metabolites of 1,3- butadiene (1,3-BD; e.g., trihydroxybutyl mercapturic acid [THBMA] and dihydroxy-butyl-mercapturic acid [DHBMA]) and toluene (e.g., benzylmercapturic acid-2 [BMA-2]). Following the analysis of blood urea nitrogen (BUN) and estimated glomerular filtration rate (eGFR_Schwartz), magnetic microsphere technology was used to measure neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C (Cys C). The median THBMA and BMA-2 levels were 5.70 and 5.20 ng/mL, respectively. Higher toluene metabolite levels were unexpectedly observed in children attending the more distant schools, likely reflecting local emission sources may play certain role. Children attending schools near petrochemical complexes had higher median urinary NGAL (13.7 vs. 8.94 ng/mL, p < 0.001) and Cys C levels (3.36 vs. 1.88 ng/mL, p = 0.003) than did those attending more distant schools. BUN was significantly and positively associated with THBMA (β = 0.019, p = 0.017) and BMA-2 (above the 75th percentile; β = 0.088, p = 0.022), involving an approximately 3.1-fold increased risk of abnormal uric acid levels in urine samples (p = 0.029). DHBMA levels above the 75th percentile were significantly and positively associated with the creatinine clearance rate (β = 0.029, p = 0.015) and eGFR_Schwartz (β = 0.060, p = 0.020) showing observed approximately 2.4-fold increased risk of glomerular hyperfiltration. This study provides the first evidence of exposure to 1,3-BD and toluene among children, suggesting that persistent hyperfiltration may associated with accelerated nephron loss with later renal function decline and ambient hazardous volatile compounds surrounding petrochemical complexes could alter kidney function in school-aged children.