• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.4
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• pp.356-363
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• 2006

To investigate the exposure effect of benzene, we measured airborne benzene as external doses, uninary tt-muconic acid as an internal dose of benzene exposure and analyzed the relationship between tt-muconic acid concentration and benzene exposure. The study population of eight businesses included 157 workers(87 workers in field; exposure group, 70 workers in board; control group) who produce or use benzene in petrochemical industry. The concentrations of airborne benzene were evaluated by personal samples and urine was sampled at the pre and end shift. Urinary t,t-muconic acid as internal dose was to analyze the relationship with airborne benzene. The geometric means(GM) of airborne benzene was 0.0231 ppm(range ND-1.0471 ppm) in exposure group and 0.0147 ppm(range ND-0.3162 ppm) in control group. The geometric means(GM) of urinary t,t-muconic acid at end-shift was $196.8{\pm}2.23{\mu}g/g$ creatinine in exposure group and $149.2{\pm}2.08{\mu}g/g$ creatinine in control group. There was significant correlation between the airborne concentration of benzene and the urinary concentration of t,t-muconic acid( r=0.711, p<0.01). From the results of stepwise multiple regression analysis about t,t-muconic acid at end-shift, significant independents was airborne benzene. In this study, there were significant correlation between the urinary concentration of t,t-muconic acid and the airborne concentration of benzene. More extensive studies ruling out healthy worker effect is needed.

• Biotechnology and Bioprocess Engineering:BBE
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• v.1 no.1
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• pp.36-40
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• 1996

For the production of cis, cis-muconic acid via biocatalytic conversion reactions from a toxic cosubstrate, benzoic acid, a fed-batch process using computer-controlled DO-stat feeding was developed. The mutant strain of Pseudomonas putida BM014 produced cis, cis-muconic acid from benzoic acid with high conversion yield. More than 32 g/L of cis, cis-muconic acid was accumulated in 42h and a productivity of 1.4g/(L.h)was achieved.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2001.11a
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• pp.97-97
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• 2001

• Proceedings of the Korean Society of Toxicology Conference
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• 2005.05a
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• pp.131-132
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• 2005

• Safety and Health at Work
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• v.8 no.2
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• pp.220-225
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• 2017

Background: Benzene is a known occupational and environmental pollutant. Its urinary metabolite trans, trans-muconic acid (tt-MA) has been introduced by some environmental and occupational health regulatory associations as a biological index for the assessment of benzene exposure; however, recently, doubts have been raised about the specificity of tt-MA for low-level benzene exposures. In the present study, we investigated the association between urinary levels of tt-MA and inhalational exposure to benzene in different exposure groups. Methods: Benzene exposure was assessed by personal air sampling. Collected benzene on charcoal tube was extracted by carbon disulfide and determined by a gas chromatograph (gas chromatography with a flame ionization detector). Urinary tt-MA was extracted by a strong anion-exchange column and determined with high-performance liquid chromatography-UV. Results: Urinary levels of tt-MA in intensive benzene exposure groups (chemical workers and police officers) were significantly higher than other groups (urban and rural residents), but its levels in the last two groups with significant different exposure levels (mean = 0.081 ppm and 0.019 ppm, respectively) showed no significant difference (mean = $388{\mu}g/g$ creatinine and $282{\mu}g/g$, respectively; p < 0.05). Before work shift, urine samples of workers and police officers showed a high amount of tt-MA and its levels in rural residents' samples were not zero. Conclusion: Our results suggest that tt-MA may not be a reliable biomarker for monitoring low-level (below 0.5 ppm) benzene exposures.

• Analytical Science and Technology
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• v.25 no.6
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• pp.460-466
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• 2012

An environmentally friendly, so-called green, high performance liquid chromatography method was developed and validated for the determination of trans, trans-muconic acid (t,t-MA) in human urine as a biomarker of benzene exposure. After urinary t,t-MA was extracted and enriched using solid-phase extraction, a MF-Ph1 SG80 ($150mm{\times}2.0mm$ I.D., 5 ${\mu}m$) column with a mobile phase of 10 mM $KH_2PO_4$ containing 0.1% $H_3PO_4$ was used for isocratic separation of t,t-MA with UV detection at 259 nm. The calibration curve was constructed in the range of 0.1-5.0 mg/L with good linearity ($r^2$=0.9992). The intra-day and inter-day precision (as RSD) were 0.9-8.5% and 3.1-4.5%, respectively. The average recovery ranged from 97.5% to 101.7%. The green sample preparation and separation with no organic solvents were successfully achieved. The validated method would be suitable for the routine biological monitoring of benzene exposure in the occupational settings.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.1
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• pp.52-58
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• 2014

Objectives: Using laborers participating in the petrochemical factory turnaround process as subjects, this study aims to identify exposure to benzene in the air and examine the relationship between exposure and the excretion of urinary metabolites by measuring concentrations of urinary trans, trans-muconic acid (t,t-MA). Methods: A passive sampler was used to measure the level of benzene in the air. In order to analyze urinary metabolites, the urine of laborers participating in the turnaround process was collected twice daily, both before and after work. In addition, a survey was conducted on work factors and lifestyle habits as factors affecting the concentration of urinary metabolites. Results: During the survey period, benzene was detected in the samples from all workers, and its average concentration was $0.16{\pm}0.22ppm$. The average concentration of t,t-MA after work was $1.20{\pm}1.86mg/g$ creatinine, and the results of analyzing urinary metabolites concentration before and after work showed statistically significant differences(p=0.003). There was also a statistically significant correlation (r=0.52, p=0.002) between benzene in the air and the concentration of after-work urinary t,t-MA. Conclusions: During the turnaround process, the average benzene concentration in workers was $0.16{\pm}0.22ppm$, which was below the exposure limit. However, their average t,t-MA concentration was $1.20{\pm}1.86mg/g$ creatinine, which exceeded the exposure limit of 1mg/g creatinine. The characteristics of turnaround process work require considerations such as underestimating the passive sampler being used and the skin absorption of benzene, and there needs to be a simultaneous assessment of working environment measurements and biological monitoring.

• Environmental Mutagens and Carcinogens
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• v.22 no.2
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• pp.90-96
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• 2002

Benzene is a widespread human carcinogen, inducing leukemia and hematotoxicity. Exposure to benzene metabolites has been shown to cause genetic damage, including aneusomy and chromosome aberrations. Fluorescence in situ hybridization(FISH) procedure was used to determine if the benzene metabolite, 1, 2, 4-benzenetriol(BT), hydroquinone(HQ) and trans, trans-muconic acid(t,t-MA) induced specific chromosomal change in HL-60 cells. Treatment with BT, HQ and t,t-MA resulted in the induction of monosomy 8 and 21 in HL-60 cells in a dose-dependent manner. All of these metabolites also induced trisomy 8 and 21, but no correlation between frequencies of trisomy and concentration was found. Translocations between chromosome 8 and another unidentified chromosome ［t(8:\ulcorner)］, and between chromosome 21 and another unidentified chromosome ［t(8:21)］ were found. However, translocation between chromosome 8 and 21 ［t(8:21)］ was not found. Results indicate that the benzene metabolites, BT, HQ and t,t-MA, induce chromosome specific numerical and structural aberrations, and the fluorescence in situ hybridization (FISH) approach may be a useful and powerful technique for detection of aneuploidy.

• Archives of Pharmacal Research
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• v.27 no.5
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• pp.570-575
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• 2004

2-Hydroxymuconic semialdehyde (2-HMS) dehydrogenase catalyzes the conversion of 2-HMS to 4-oxalocrotonate, which is a step in the meta cleavage pathway of aromatic hydrocarbons in bacteria. A tomC gene that encodes 2-HMS dehydrogenase of Burkholderia cepacia G4, a soil bacterium that can grow on toluene, cresol, phenol, or benzene, was overexpressed into E. coli HB 101, and its gene product was characterized in this study. 2-HMS dehydrogenase from B. cepacia G4 has a high catalytic efficiency in terms of V$_{max}$K$_{max}$ towards 2-hydroxy-5-methyl-muconic semialdehyde followed by 2-HMS but has a very low efficiency for 5-chloro-2-hydroxymuconic semialdehyde. However, the enzyme did not utilize 2-hydroxy-6-oxo-hepta 2,4-dienoic acid and 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid as substrates. The molecular weight of 2-HMS dehydrogenase from B. cepacia G4 was predicted to be 52 kDa containing 485 amino acid residues from the nucleotide sequence of the tomC gene, and it exhibited the highest identity of 78% with the amino acid sequence of 2-HMS dehydrogenase that is encoded in the aphC gene of Comamonas testosteroni TA441. 2-HMS dehydrogenase from B. cepacia G4 showed a significant phylogenetic relationship not only with other 2-HMS dehydrogenases, but also with different dehydrogenases from evolutionarily distant organisms.sms.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.2
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• pp.152-159
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• 2014

Objectives: This study aims to investigate the excretion aspect of urinary t, t-MA and hippuric acid by measuring concentrations of urinary metabolites according to the use of gasoline vapor recovery system. Materials:In order to analyze urinary metabolites, samples from the 23 gas station workers ten gas stations in the Seoul and Gyeonggi Province area were collected once daily after work. In addition, a survey was conducted on work factors and lifestyle habits as factors affecting the concentration of urinary metabolites. Results: The average concentrations of t, t-MA and hippuric acid after work were $0.124{\pm}0.177mg/g$ creatinine and $0.557{\pm}0.251g/g$ creatinine among workers at gas stations where gasoline vapor recovery systems were installed. The average concentrations of t, t-MA and hippuric acid were $0.160{\pm}0.113mg/g$ creatinine and $0.682{\pm}0.619g/g$ creatinine among workes at gas stations where gasoline vapor recovery systems were not installed. Average concentrations were higher at gas stations where a gasoline vapor recovery system was not installed, but the differences were not statistically significant differences. Urinary t, t-MA and hippuric acid average concentrations of smokers and non-smokers were higher in the gas stations where gasoline a vapor recovery system was not installed. T, t-MA as a factor evaluation affecting the concentration of urinary metabolites was not statistically significant in all factors, while hippuric acid was statistically significant only for age(p=0.024). Conclusions: The average concentrations of urinary t, t-MA and hippuric acid were higher in gas stations where gasoline vapor recovery systems were not installed compared to gas stations where such a system was installed. There needs to be an assessment of biological monitoring according to refueling activity considering skin absorption of benzene and toluene and presence of gasoline vapor recovery system.