Annals of Occupational and Environmental Medicine

Original Article

Urinary Excretion of Thiodiglycolic Acid According to Sampling Time in Workers Exposed to Vinyl Chloride Monomer: Hyun Soo Kim, Chi Nyon Kim, Jong Uk Won, Bong Suk Cha, Kyung Jong Lee, Jaehoon Roh; Korean Journal of Occupational and Environmental Medicine 2006;18(2):138-145. Published online June 30, 2006; DOI: https://doi.org/10.35371/kjoem.2006.18.2.138

OBJECTIVES
The study was performed to investigate the changes of urinary thiodiglycolic acid (TDGA) concentration in workers exposed to vinyl chloride monomer (VCM) according to the time of sampling urine.
METHODS
The personal exposure to airborne VCM was assessed and urinary TDGA concentration was sampled in 31 workers employed in a VCM and polyvinyl chloride (PVC) manufacturing factory. Urinary TDGA was sampled three times: before the start of the shift after 3 days off (TDGA1), after the end of the first-day shift (TDGA2) and before starting the following day shift after completing the oneday shift (TDGA3). Urinary TDGA in 30 workers who had not been exposed to airborne VCM was sampled after the end of the shift. A gas chromatography/pulsed flame photometric detector (GC/PFPD) was utilized to analyze TDGA concentration in urine after the urine was methylated with trimethylsilyldiazomethane(2.0M in diethyl ether).
RESULTS
The creatinine level was 0.179+/-0.271 mg/g in the control workers and 0.218+/-0.443 mg/g in the workers before the start of the shift after 3 days off (TDGA1), showing no significant difference (p=0.7035). Urine samples were compared according to sampling time in order to investigate the change of urinary TDGA concentration in the case of continuous exposure to airborne VCM. In VCM-exposed workers, urinary creatinine concentration was 0.434+/-0.623 mg/g in TDGA2 and 0.767+/-1.056 mg/g in TDGA3, which indicated a gradual but significant increase (p=0.024). In terms of the statistical correlation between airborne VCM and urinary TDGA to evaluate exposure dose per day, of the three urinary TDGA concentrations, TDGA3 showed the highest degree of regression (R(2)=0.4215) with 8h-TWA airborne VCM concentration.
CONCLUSION
Based on this result, the excretion half-life of urinary TDGA was assumed to be less than 3 days, because the concentration of urinary TDGA at 3 days after exposure to airborne VCM was decreased to the level of urinary TDGA concentration in the control workers. The concentration of urinary TDGA increased in the case of continuous shift, due to the accumulation of residual metabolites of TDGA. It was considered that TDGA3 can be applied as a useful biological index to evaluate the exposure dose of airborne VCM during one day because TDGA3 showed the highest correlation with the exposure dose of airborne VCM in the previous shift day.

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Assessment of urinary thiodiglycolic acid exposure in school-aged children in the vicinity of a petrochemical complex in central Taiwan
Po-Chin Huang, Li-Hsuan Liu, Ruei-Hao Shie, Chih-Hsin Tsai, Wei-Yen Liang, Chih-Wen Wang, Cheng-Hsien Tsai, Hung-Che Chiang, Chang-Chuan Chan
Environmental Research.2016; 150: 566. CrossRef

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Original Article

The variation of thiodiglycolic acid concentration in urine with vinyl chloride exposure levels in rats: Seung Jun Wang, Bong Suk Cha, Jae Hoon Roh, Dong Chun Shin, Myung Su Kim, Keun Jae Jeon; Korean Journal of Occupational and Environmental Medicine 1999;11(4):431-438. Published online December 31, 1999; DOI: https://doi.org/10.35371/kjoem.1999.11.4.431

Abstract PDF: OBJECTIVES
It is the objective of this research to identify the variation of thiodiglycolic acid (TdGA) in urine with vinyl chloride monomer (VCM) exposure levels through methylation.
METHODS
After rats were exposed to vinyl chloride monomer of 4 levels, 0 mg/m3, 50 mg /m3, 150 mg/m3, 500 mg/m3, respectively, of which urine was sampled in each sampling time of 0 hour, 2 hours, 4 hours, 8 hours, 16 hours, 24 hours, 36 hours, 48 hours. After urine had been methylated with diazomethane in the preliminary experiment and the peak of 146 m/z had been verified, the main experiment was done.
RESULTS
In the variation of TdGA with sampling times, concentration of TdGA increased rapidly in 4 hours and then decreased after 8 hours. When the variation of urinary .TdGA concentration in urine according to exposure level of VCM was verified through Kruskal-Wallis statistical method at each sampling time, the significant increment with the exposure levels at 2 hours, 4 hours, 8 hours after exposure was clarified.
CONCLUSION
TdGA concentration in urine with increment of VCM exposure level increased, especially significantly at 2 hours, 4 hours, 8 hours of sampling time.

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