Occupational Exposure to Phenolic Compounds at Coke Plants-Urinary Excretion of Methoxyphenols as an Indicator of Exposure to Methoxyphenols

Objectives： This study describes the exposure of coke plant workers to methoxyphenols. The relationship between exposure to methoxyphenols and urinary excretion of metabolites was examined. Methods： We determined concentrations of 2-methoxyphenol, 2-methoxy-4-methylphenol and 1-(4-hydroxy-3-methoxyphenyl)ethanone in the breathing-zone air and in the urine of workers, collected after the workshift. Urine metabolites were extracted after enzymatic hydrolysis by solid-phase extraction. Concentrations of methoxyphenols in air and urine were determined by gas chromatography with flameionization. Results： The time-weighted average concentrations (median) of methoxyphenols in the breathing zone air were as follows： 9.9 ng/m3, 15.4 ng/m3 and 92.5 ng/m3 for 2-methoxyphenol, 2-methoxy-4-methylphenol and 1-(4-hydroxy-3-methoxyphenyl) ethanone, respectively. The median values of urinary concentrations were as follows： 582.5, 190.1, 235.0 and 21.8μmol/mol creatinine for 2-methoxyphenol, 2-methoxy-4 methylphenol, 1-(4-hydroxy-3-methoxyphenyl)ethanone and 2,6-dimethoxyphenol, respectively. A statistically significant correlation between the exposure level and the urinary level was found for 2-methoxyphenol (r=0.573, p