Korean J Occup Environ Med.
2006 Sep;18(3):163-170.
Effect of Sodium Benzoate on Change of Urinary Hippuric Acid and Methyl Hippuric Acid among Workers Coexposed to Toluene and Xylene
- Affiliations
-
- 1Department of Occupational Medicine, School of Medicine, Konkuk University, Korea.
- 2Department of Preventive Medicine, School of Medicine, Konkuk University, Korea. schang@kku.ac.kr
- 3Department of Preventive Medicine and Institute of Occupational Medicine, Wonju College of Medicine, Yonsei University, Korea.
- 4Department of Preventive Medicine, College of Medicine, Seoul National University, Korea.
Abstract
OBJECTIVES
This study was performed to investigate the effect of drink containing sodium benzoate on the change of urinary hippuric acid (UHA) and methyl hippuric acid (UMHA) excretion among workers coexposed to low toluene and xylene.
METHODS
Study subjects were 55 male shipbuilders who were divided into 3 groups; nonexposed group (n=10, who were not exposed to organic solvent and had drunk sodium benzoate), exposed A group (n=24, who were coexposed to toluene and xylene, and had drunk sodium benzoate), and exposed B group (n=21, who were coexposed to toluene and xylene, and had not drunk sodium benzoate). The study methodology consisted of questionnaire survey, urinary analysis for metabolites of toluene and xylene before and after drinking with or without sodium benzoate, and personal air sampling of toluene and xylene.
RESULTS
Before drinking, there was no significant difference in UHA or UMHA between the exposed A and B groups. After 1.5 hour of drinking, UHA of the exposed A group was significantly higher than that of the exposed B group. After 3 hours, however, UHA of the exposed A group was decreased to the level of the exposed B group, regardless of the ambient toluene level. UMHA exhibited no significant difference between the exposed A and B groups regardless of time and ambient toluene level. The regression model showed that drinking of sodium benzoate was positively correlated with UHA after 1.5 hours of drinking, but not after 3 hours. In addition, sodium benzoate didn't affect UMHA.
CONCLUSIONS
This study showed that sodium benzoate initially increased UHA temporally but that its effect disappeared after 3 hours. In the medical examination of toluene exposure workers, the ingestion of drink containing sodium benzoate should be forbidden during the 3 hours prior to urinary sampling.