• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.1
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• pp.27-35
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• 2006

The aim of this study was to identify the sources of benzene detected in airborne of casting workplace where benzene was not used as raw material. We have identified benzene by GC/FID and GC/MSD. In this pilot test, small size iron chamber(diameter 30 cm, height 20 cm) was used. As the raw materials, new sand, recovered sand, and mixed casting sand(new sand + solidifying agent + organic resin + coating material) was tested, respectively. In the new sand benzene was not detected, but in the recovered sand and the mixed casting sand was detected. Xylenesulfonic acid(solidifying agent), one of the mixed casting sand ingredients was thought to product benzene by thermal decomposition above $400^{\circ}$..., but the other raw materials(organic resin and coating material) were thought not to product benzene. In this experiment, the most of benzene by thermal decomposition was produced within 1 hour after pouring the iron solution($1560^{\circ}$...) in small size iron chamber. When the mixed casting sand with coating material was used, the concentration of the produced benzene was average 2.91 ppm(range 1.98~3.72 ppm), and without coating material, benzene concentration was average 0.11 ppm(range 0.08~0.14 ppm).

• Korean Journal of Environmental Agriculture
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• v.29 no.4
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• pp.421-426
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• 2010

Benzene is one of volatile environmental pollutants to induce asthma and allergy in respiratory system. The airway epithelium is a physical barrier to inhaled toxicants and particulates. However, the effect of benzene in lung epithelial cell viability has not been elucidated. Thus, this study was conducted to investigate the effect of benzene on apoptosis in A549 cells, lung epithelial cell line. In this study, benzene decreased cell viability of A549 cells in a dose-dependent manner (> $10{\mu}M$). Benzene-induced decrease of cell viability was blocked by the treatment of antioxidants (vitamin C and NAC). Indeed, benzene induced lipid peroxide formation in A549 cells. Benzene decreased Bcl-2 expression but increased Bax expression in A549 cells. In addition, benzene also increased the cleaved form of caspase-3. In conclusion, benzene induced apoptosis via oxidative stress in cultured epithelial cells.

• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.379-383
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• 1988

To evaluate the treatability of activated sludge induced by benzene with microorganisms, isolation and characterization of benzene-degrading microorganisms were carried out. Six bacterial isolates from the activated sludge were identified ; Pseudomonas fluorescens, Enterobacter agglomerans, Enterobacter cloacae, Klebsiella oxytoca, Citrobacter freundii and Klebsiella pneumoniae. P. fluorescens degraded 55% of benzene contained in the medium as a sole carbon source, E. cloacae 24%, E. agglomerans 41%, and K. oxytoca 32%. Optimal temperature, pH and benzene concentration for growth of P. fluorescens appeared to be 31$^{\circ}C$, pH 7.0, and 300mg benzene per liter. When the P. fluorescens was dominant in the activated sludge induced by benzene, the indicator protozoa was Aspidisca sp. When concentration of benzene was about 387mg per liter, the growths of Aspidisca sp. and Litonotus sp. were high. Protozoa, Litonotus sp. and Vorticella sp. did not grow over 1600mg of benzene per liter.

• Journal of Environmental Science International
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• v.8 no.3
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• pp.319-323
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• 1999

This study was designed to evaluate the exposure to benzene by residents in neighborhoods near a major roadways, by persons waiting buses, and by drivers and service station attendants while refueling. It was confirmed that the outdoor air benzene concentrations near the major roadways were higher than those further away from the sources. However, neither the indoor air nor breath concentrations were different for two specified residential areas. Smoking was confirmed as an important factor for the indoor air benzene levels. Persons waiting buses, drivers and service station attendants were exposed to elevated benzene levels compared to even the residents in neighborhoods near a major roadways. The mean benzene concentration at bus stop was 2.7 to 6.9 times higher than the mean ambient air concentration. The mean benzene concentrations in the breathing zone of drivers and service station attendants were 95 to 160 and 120 to 202 times higher than the mean ambient air concentrations, respectively.

• KSBB Journal
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• v.15 no.6
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• pp.589-593
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• 2000

Several bacterial strains growing on benzene minimal medium were isolated from soil by enrichment culture, Burkholderia sp. SKK381 was identified and selected. In order to determine the ability of Burkholderia sp. SKK381 to degrade benzene. Changes in substrate concentration, cell growth, and pH were monitored from start-up in bath culture. At 30$^{\circ}C$, 1000 ppm of benzene was degraded 100% within 28hours. Cell growth conditions were best at an initial pH of 7.0 and a benzene concentration of 1000 ppm at 30$^{\circ}C$.

• Journal of Environmental Science International
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• v.7 no.3
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• pp.393-400
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• 1998

A microorganism, Klebsiella gr. 47, capable of degrading BTX(benzene, toluene and xylene) was isolated from oil-contaminated soil and its characteristics of BTX degradation were investigated. When benzene and toluene were fed to Klebstella gr. 47 simulataneously, they showed competitive ingibition. The degradation rate of xylene was enhanced as much as 3 times when xylene was fed with benzene or toluene. Degradation rate of benzene and toluene was also enhanced by cocultured with Alcaligenes xylosoxidans. When benzene-adapted microorganism was used, each BTX compound was degraded efficiently within 5 hours.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.96-102
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• 2003

Benzene is an environmental pollutant that is present in mineral oil, natural gas, coal tar, gasoline, motor vehicle emissions, and tobacco smoke. The importance of benzene resides in the fact that it can induce hematotoxicity and leukemia in human and mice. However, the underlying mechanism of benzene hematotoxicity and leukemogenicity is still not fully understood.(omitted)

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1287-1288
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• 2001

• Fire Science and Engineering
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• v.27 no.1
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• pp.8-13
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• 2013

The autoignition temperature (AIT) is important index for the safe handling of flammable liquids which constitute the solvent mixtures. This study measured the AITs and ignition delay time for Benzene and n-Hexane system by using ASTM E659 apparatus. The AITs of Benzene and n-Hexane which constituted binary system were $583^{\circ}C$ and $240^{\circ}C$, respectively. The experimental AITs of Benzene and n-Hexane system were a good agreement with the calculated AITs by the proposed equations with a few A.A.D. (average absolute deviation).

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.1
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• pp.57-66
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• 2003

TiO$_2$ sol was prepared by sol-gel method, and this sol was coated in ceramic and glass bead by dip-coating method. The coated catalyst was applied to degrade benzene in the gas phase by exposing to UV -lamp (365 nm) in a batch reactor. The removal efficiency of the benzene was compared by changing various conditions such as the kind of chemical additives, the coating beads (ceramic and glass), solution pH, the initial concentration of TiO$_2$ sol, UV intensity, and benzene concentration. The physical structure of TiO$_2$ sol used in this study was found to be pu-rely anatase type from XRD analysis. The results showed that ceramic bead was effective as the coating agent rath-er than glass bead. The significant change in the benzene removal efficiency of benzene did not occur with chang-ing coating frequency and the initial concentration of TiO$_2$ sol. The removal efficiency of benzene increased with increasing UV intensity, and with acidic treatment of TiO$_2$-coated ceramic bead.