Effect of ethanol on the urinary excretion of cyclohexanol and cyclohexanediols, biomarkers of the exposure to cyclohexanone, cyclohexane and cyclohexanol in humans

Objectives This study explored the acute effect of ethanol (EtOH) on the ur inary excretion of cyclohexanol (CH-ol), 1,2- and 1,4-cyclohexanediol (CH-d iol), biomarkers of exposure to important solvents, and chemical intermedia tes cyclohexanone (CH-one), cyclohexane (CH) and cyclohexanol. Methods Volunteers (5-8 in each group) were exposed for 8 hours either to C H-one, CH or CH-ol vapor at concentrations of about 200, 1000, and 200 mg/m (3), respectively, with concomitant ingestion of EtOH (4 14-g doses taken d uring the exposure). Urine was collected for 72 hours and analyzed for CH-o l and CH-diols using a procedure involving acidic hydrolysis and gas chroma tographic determination. Results The metabolic yields of CH-ol, 1,2-, and 1,4-CH-diol, respectively, in the exposures with EtOH were as follows: 11.3%, 36%, 23% after the expo sure to CH-one, 3.1%, 15%, 8% after the exposure to CH, and 6.6%, 24%, 18% after the exposure to CH-ol. [The corresponding values obtained previously in matching experiments without EtOH were as follows: 1.0%, 39%, 18% (CH-on e); 0.5%, 23%, 11% (CH); and 1.1%, 19%, 8% (CH-ol).] The excretion curves o f the metabolites in the exposures with EtOH were not delayed when compared with the corresponding curves of a comparison group. Conclusions The urinary excretion of CH-diols is much less sensitive to EtO H than that of CH-ol. It is recommended to employ CH-diols as useful and mo re reliable biomarkers of exposure to CH-one, CH and CH-ol in field examina tions.