Urinary profiles to assess polycyclic aromatic hydrocarbons exposure in coke-oven workers

Aim: Aim of the study was the assessment of exposure of Polish coke oven workers to polycyclic aromatic hydrocarbons (PAHs) by determination of urinary profiles of hydroxylated and unmetabolized PAHs. The influence of smoking habit, and polymorphism of glutathione S-transferase GSTM1 and CYP1A1 on biological markers excretion was also evaluated. Methods: Polish coke oven workers (n=55) were investigated by measurement of 12 hydroxylated metabolites of PAHs (OH-PAHs) (1-, 2-hydroxynaphthalene; 2-, 9-hydroxyfluorene; 1-, 2-, 3-, 4-, 9-hydroxyphenanthrene; 1-hydroxyypyrene, 6-hydroxychrysene and 3-OHbenzo(a)pyrene) and 13 unmethabolized PAHs (U-PAHs) (from naphthalene to benzo[a]pyrene), in urine spot samples collected at the end of the workshift, after at least three consecutive days of work. OH-PAHs were determined by GC-MS following enzymatic hydrolysis, liquid/liquid extraction and derivatisation, while U-PAHs were measured by headspace-solid phase microextraction GC-MS. Results: U-PAHs with 4 or less rings were detected in all samples. In particular, median levels for urinary naphthalene, phenanthrene, fluoranthene, pyrene and chrysene were 804, 718, 139, 20 and 32 ng/L. High-boiling U-PAHs were found in less than 25% of the samples (range <15-140 ng/L). Preliminary results regarding OH-PAHs show the presence of low boiling compounds in all samples (range <0.1-358 µg/L). The presence of high molecular weight OH-PAHs was also detected. In all subjects significant correlations between OH-PAHs and U-PAHs were observed (0.27<r<0.70, p<0.01). Genetic polymorphisms of metabolic enzymes and cigarette smoking had no influence on the excretion of either metabolized and unmetabolized biomarkers. Conclusions: In this study the measurement of both OH-PAHs and U-PAHs in coke oven workers is reported for the first time. Our results suggest that both hydroxylated metabolites and unmetabolized PAHs in urine are useful biomarkers of exposure to PAHs. Moreover the simultaneous determination of several biomarkers permits to obtain specific excretion profiles that might help in exposure characterization and in better defining the excretion pattern of the different compounds.