PT Journal AU Bieniek, G TI Urinary naphthols as an indicator of exposure to naphthalene SO Scandinavian Journal of Work, Environment & Health PD 12VL PY 1997 BP 414 EP 420 IS 6 DI 10.5271/sjweh.263 WP https://www.sjweh.fi/show_abstract.php?abstract_id=263 DE biological monitoring; naphthalene exposure; urinary metabolite SN 0355-3140 AB '

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OBJECTIVES ': 'The relationship between exposure to naphthalene and urinary excretion of naphthols was examined.

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METHODS ': 'Concentrations of naphthalene and naphthols in breathing-zone air during a workshift and 1-naphthol and 2-naphthol in urine collected after the workshift were determined for 102 male workers. Gas chromatography with a flame ionization detector (GC-FID) was used to determine the air concentration. Urine naphthols were extracted after acid hydrolysis by solid-phase extraction and separated by the GC-FID method. Naphthalene homologues in air and their metabolites in urine samples were identified by gas chromatography-mass spectrometry.

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RESULTS ': '1-Naphthol, 2-naphthol and 1,4-naphthoquinone were identified in the urine samples. The time-weighted average concentrations of naphthalene and naphthols in the breathing-zone air showed that the exposure level of the workers was rather low. The geometric mean values were as follows: 0.77 and 0.87 mg/m3 for naphthalene, 0.016 and 0.034 mg/m3 for 1-naphthol, 0.012 and 0.067 mg/m3 for 2-naphthol during tar distillation and naphthalene oil distillation, respectively. The corresponding urinary concentrations of 1- and 2-naphthols were 693.1 and 264.4 µmol/mol and 264.4 and 297.7 µmol/mol creatinine, respectively. The correlation coefficients between the naphthol concentrations in urine and the breathing-zone air concentrations of naphthalene were statistically significant, varying in the range of 0.64–0.75 for 1-naphthol and 0.70–0.82 for 2-naphthol. There was linear dependence (r = 0.76) between the summary concentration of naphthols in urine and the naphthalene concentration in air.

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CONCLUSION ': 'Workers in tar distillation and naphthalene distillation are exposed to rather low concentrations of naphthalene and methylated naphthalenes and naphthols. Naphthols and 1,4-naphthoquinone identified in the urine appear to be the products of the hydroxylation of naphthalene present in the breathing-zone air. These findings suggest that the summary concentration of naphthols in urine can be used as a biomarker for naphthalene exposure.

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