Benzylmercapturic acid is superior to hippuric acid and o-cresol as a urinary marker of occupational exposure to toluene.
The present study was initiated to examine whether urinary benzylmercapturic acid (or N-acetyl-S-benzyl cysteine, BMA), a mercapturate metabolite of toluene, increases in relation to the intensity of toluene exposure, and whether this metabolite is a better marker of occupational exposure to toluene than two traditional markers, hippuric acid and o-cresol. Accordingly, end-of-shift urine samples were collected from 122 printers and 30 office clerks (all men) in the second half of a working week. Solvent (toluene) exposure of the day (8 h) was monitored by means of diffusive sampling. Quantitative relation with toluene showed that BMA had a greater correlation coefficient with toluene (r = 0.7) than hippuric acid (r = 0.6) or o-cresol (r = 0.6). The levels in the urine of the non-exposed control subjects were below the detection limit of 0.2 microg/l for BMA, whereas it was at substantial levels for hippuric acid and o-cresol (239 mg/l and 32 microg/l as a geometric mean, respectively). Thus, BMA, hippuric acid and o-cresol could separate the exposed from the non-exposed when toluene was at < 1, 50 and 3 ppm, respectively. Overall, therefore, it appeared reasonable to conclude that BMA is superior to hippuric acid and o-cresol as a marker of occupational exposure to toluene.
Inoue
O
O
Tohoku Rosai Hospital, Sendai 981-0911, Japan.
Kanno
E
E
Kasai
K
K
Ukai
H
H
Okamoto
S
S
Ikeda
M
M
D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000652:urine*; D000328:Adult; D015415:Biomarkers; D002851:Chromatography, High Pressure Liquid; D003408:Cresols / Q000652:urine*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006626:Hippurates / Q000652:urine*; D006801:Humans; D007202:Indicators and Reagents; D008297:Male; D016273:Occupational Exposure / Q000032:analysis*; D012044:Regression Analysis; D012997:Solvents; D014050:Toluene / Q000009:adverse effects*
D015415:Biomarkers; D003408:Cresols; D006626:Hippurates; D007202:Indicators and Reagents; D012997:Solvents; D014050:Toluene; C030514:hippuric acid; D000111:Acetylcysteine; C029319:S-benzyl-N-acetyl-L-cysteine; C034047:2-cresol