Evaluation of urinary cyclohexanediols and cyclohexanol as biomarkers of occupational exposure to cyclohexane

[Abstract]: Evaluation of urinary cyclohexanediols and cyclohexanol as biomarkers of occupational exposure to cyclohexane: Akito TAKEUCHI, et al. Osaka Occupational Health Service Center, Japan Industrial Safety and Health Association - Objectives: The aim of the present study was to comparatively evaluate the usefulness of urinary cyclohexanediols (CHdiols-U) and cyclohexanol (CHol-U) as biomarkers of occupational exposure to cyclohexane (CH). Methods: Sixteen subjects (14 men and 2 women) were exposed to CH during proof-printing work. Personal exposure monitoring was conducted during the whole shift on the last working day of the week. The time-weighted average level of exposure to CH (CH-A) was measured using a diffusive sampler. Two urine samples were collected from each worker at different times during the same week: a baseline urine sample (before the first shift of the working week, after a 5-day holiday with no CH exposure) and an end-of-shift urine sample (after the last shift of the same working week, the same day personal exposure monitoring was conducted). CH-A, CHdiols-U and CHol-U were determined using a gas chromatograph-flame ionization detector. Results: The CH-A concentrations ranged from 4.5 to 60.3 ppm, with a geometric mean (GM) of 18.1 ppm. The GMs and ranges (in parenthesis) of the creatinine (cr)-corrected end-of-shift 1,2-CHdiol-U, 1,4-CHdiol-U and CHol-U concentrations were 12.1 (4.1-36.6), 7.5 (2.4-20.1) and 0.4 (0.2-1.0) mg/g cr, respectively. Both CHdiols-U at the end of the shift were significantly correlated with CH-A (correlation coefficients for 1,2-CHdiol-U and 1,4-CHdiol-U of 0.852 and 0.847, respectively). No correlation was observed between CH-A and CHol-U. Conclusions: CHdiols-U at the end of the last shift of the working week are suitable biomarkers of occupational exposure to CH, but CHol-U is not suitable.