EFFECTS OF SMOKING AND DRINKING HABITS ON URINARY O-CRESOL EXCRETION AFTER OCCUPATIONAL EXPOSURE TO TOLUENE VAPOR AMONG CHINESE WORKERS

The relationship between the time-weighted average intensity of exposu re to toluene and o-cresol concentration in shift-end urine was invest igated in nearly 500 factory workers of both sexes in China, together with a similar number of nonexposed control subjects. Toluene concentr ation (25 ppm as geometric mean and 550 ppm as the maximum) was monito red by diffusive sampling using carbon cloth as adsorbent followed by gas chromatographic (GC) analysis, o-Cresol (up to 7 mg/l) was measure d by GC after acid hydrolysis of samples. Urinary o-cresol levels corr elated significantly (r = 0.69-0.77; p < 0.01) with toluene exposure i n men, women and the two sexes in combination, regardless of correctio n for urine density. When compared with hippuric acid, however, o-cres ol was less sensitive as an indicator of exposure to toluene and is no t a suitable biological marker for detecting low level toluene exposur e. Since urinary o-cresol level was significantly reduced by smoking, drinking, and the two habits combined, it cannot be considered reliabl e as an indicator of exposure to toluene. (C) 1994 Wiley-Liss, Inc.