Relationship between exposure to toluene and excretion of urinary metabolites in Korean female solvent workers.

Toluene is known to be the most popular solvent for industrial use,1,2) and attention has been paid on the possibility of biological monitoring of toluene exposure by urinalysis for metabolites such as hippuric acid and o-creso1.3-5) In a previous study6) on possible ethnic difference in toluene metabolism, it was disclosed that Chinese toluene workers excrete less hippuric acid in urine than their counterpart Japanese workers while o-cresol excretion is essentially comparable, and that the ratio of o-cresol over hippuric acid is highest among Turkish workers followed by Chinese and lowest among Japanese. It was thought interesting then to study toluene metabolism in Korean population who live geographically in the area located between. Chinese Continent and Japanese Islands. Korean female workers at 16 to 44 years of age (mostly at 20's) in Masan, Korea, participated in the study. Of these workers, 181 subjects were engaged in the production of shoes and exposed to toluene as they applied toluenecontaining glue. The workroom air analysis by diffusive sampling and gaschromatography revealed that the major solvent in air was toluene; other solvents detected included n-hexane, cyclohexane and methyl ethyl ketone, but their levels were less than one tenth of that of toluene. Remaining 68 people had no exposure to toluene and served as nonexposed controls. The time-weighted average concentration of toluene in breath zone air during a shift of the day was monitored by means of personal samplers of diffusion type with carbon cloth K-filter 1500 as adsorbent (Toyobo Co., Osaka, Japan); the adsorbed solvents were extracted into carbon disulfide, a portion of which was subjected to FID-gaschromatography.7,8) Urine samples were collected from the exposed and nonexposed participants at 3 to 4 p.m. on the study day in the latter half of a week, and analyzed for hippuric acid and o-cresol by means of high performance liquid chromatography and gaschromatography, respectively, as previously described.9) The observed values were corrected for creatinine concentration10) and a specific gravity of urine of 1.016.11) Due caution on the stability of the solvents in the carbon cloth8,12) and the metabolites in urine9) was exercised so that the data