Evaluation of urinary D-glucaric acid excretion in workers exposed to butyl glycol

The biological follow-up of subjects exposed to butyl glycol (BG) is generally accomplished using a standard blood count that is not sensitive enough to reveal early intoxication by this molecule. For this reason we have used an indirect test for evaluating the induction of hepatic enzymes, the measurement in urine of D-glucaric acid (DGA), which reflects the activity of the glucuronic acid enzyme pathway. This study was performed on 17 foundry workers exposed to BG emissions coming from paints used in cataphoresis. The airborne concentration of BG was less than 0.3 times the average limit exposure value. This study shows that BG emissions at low concentrations are able to increase the activity of the enzymes of the glucuronic acid pathway. DGA urinary excretion increased by 165% in winter (p < .01) and by 85% (p < .05) in summer when the doors are open and the BG concentration lower. DGA urinary excretion is significantly higher in smoking than in nonsmoking exposed workers. None of these workers had a perturbed blood count. This study shows that the urinary level of DGA provides a good test for the follow-up of exposure to BG in the electrophoresis painting plant, and that the exposed smoking workers seem to be more sensitive to BG exposure than do the nonsmokers. In conclusion, the measurement of urinary DGA might be considered as a useful test for the surveillance of subjects exposed to vapors containing BG.