urinary hippuric acid and toluene levels in workers of printing factories in thailand

the aims of this study were to determine hippuric acid and toluene in urine samples, airborne toluene levels, health effects, and to describe any correlation between specimen samples. seventy-five printing workers exposed to toluene at work (exposed group), and 60 nonexposed people (control group) were studied. study participants were selected from same factories in the different positions. urine samples were collected at the end of a shift and analyzed for hippuric acid, toluene in urine, and airborne toluene by using gas chromatograph (gc). the median of the 75 airborne toluene levels was 11.16 ppm (range, 3.72-68.83 ppm). the median of the urinary hippuric acid level was 200 mg/g creatinine (range, 78-1870 mg/g creatinine), and toluene in urine was 13 µg/l (range, 11-58 µg/l). a statistically significant positive correlation was found among airborne toluene exposure, hippuric acid levels, and urinary toluene levels (r= 0.713, p<0.001, and r= 0.738, p<0.001, respectively) and the relationship between toluene in urine levels and hippuric acid levels was significant (r=0.578, p<0.001). workers with health effects were exposed to significantly higher toluene levels than those who did not (p < 0.05). improvements in working conditions and occupational health education are required at these workplaces.