This study was conducted to provide accurate biological monitoring for workers who were exposed to benzene and ethanol pre-exposed condition. For the purpose of this study, an animal experiment was conducted to evaluate the effects of pretreatment of ethanol, which are known to effect metabolism of xenobiotics, on the excretion of urinary phenol and S-phenylmercapturic acid (SPMA) in the rats administered benzene.
The following concentrations of solvents were administered orally to Sprague-Dawley rats: Benzene was administered 2.26 mg/kg body weight (equal concentration to 2.5 ppm, TLV-STEL in USA) and 9.02 mg/kg body weight (equal concentration to 10 ppm, OEL-TWA in Korea). As well, 1g/kg body weight ethanol was pretreated. Hydrolyzed phenol and SPMA were analyzed by gas chromatography -flame ionization detector (GC-FID) and gas chromatography -mass selective detector (GS-MSD). The quantitative amount o fthe urinary metabolites was expressed by calibration of creatinine.
The concentration of phenol and SPMA decreased markedly at the initial phase in the ethanol pre-treated group compared with the control group and the concentration was slightly increased with elapsed time. This phenomenon wasremarkable for the concentration of 2.26 mg/kg than 9.02 mg/kg of benzene administration. The total excreted amount of phenol and SPMA in urine decreased in the ethanol pretreated group compared with the control group and this phenomenon was remarkable for the concentration of 9.02 mg/kg in the control group. Urinary phenol excretion was more increased in 2.02 mg/kg benzene and pre-ethanol administered group compared with the benzene-only administered group. The urinary excretion of phenol and SPMA was delayed in the case of the ethanol pretreated group, and these effects are dependent on the amount of benzene administration.
Benzene metabolism was suppressed by ethanol, and as a result, the excretion of phenol and SPMA as a urine metabolites of benzene was delayed. This result will have applications in the interpreted of results from future biological monitoring of drunken workers. It´s should not underestimated that the importance of carefully interpreting the results of biological monitoring data when workers are exposed to pre-ethanol consumption before work.
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