Relationship of exposure to coke-oven emissions and urinary metabolites of benzo(a)pyrene and pyrene in coke-oven workers

Coke-oven workers are occupationally exposed to a high concentration of polycyclic aromatic hydrocarbons (PAH). r-7,t-8,9,c-10-Tetrahydroxy-7,8,9,10-tetrahydrobenzo(a)pyrene (trans-anti-BaP-tetraol) and 1-hydroxypyrene (1-OHP) are urinary metabolites of benzo(a)pyrene and pyrene, respectively. In this study, we investigated the relationship among individual air exposure to benzene soluble fraction (BSF) of total particulates, as a surrogate marker of ambient PAH exposures, and urinary trans-anti-BaP-tetraol and 1-OHP concentrations in coke-oven workers at a steel plant in Taiwan. Fifty-seven subjects, including 41 male workers who work in one coke-oven plant and 16 men (referents) from an administrative area, were studied. The mean trans-anti-BaP-tetraol and 1-OHP concentrations (mean ± SD) were 0.4 ± 0.3 nmol/mol creatinine and 9.7 ± 21.6 μmol/mol creatinine, respectively, in coke-oven workers. These levels were significantly higher than those in referents (0.03 ± 0.03 nmol/mole creatinine, P < 0.001 and 0.4 ± 0.2 μmol/mol creatinine, P < 0.01, respectively). Urinary trans-anti-BaP-tetraol concentrations were significantly and positively correlated with individual average BSF and urinary 1-OHP concentrations. That is, the higher the urinary trans-anti-BaP-tetraol concentrations, the more ambient BSF exposure and urinary 1-OHP concentrations (Spearman correlation coefficients r = 0.68 and 0.70, respectively; P < 0.0001; n = 57). These findings suggest that urinary 1-OHP and trans-anti-BaP-tetraol might be considered as potential biomarkers for the assessment of uptake of known PAH carcinogens in the air.