• Journal of Life Science
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• v.24 no.1
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• pp.54-60
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• 2014

Aromatic hydrocarbons are toxic environmental pollutants that are detrimental to the ecosystem and human health. Among them, chlorotoluene and nitrotoluene are toxic to hydrobios and irritate the skin, eyes, and respiratory organs of humans. We herein report the development of recombinant microbial biosensors for cheap and rapid monitoring of chlorotoluene and nitrotoluene compounds. Plasmids were constructed by inserting the xylR regulatory gene for BTEX (benzene, toluene, ethylbenzene, and xylene) degradation into upstream of Po' (the DmpR activator promoter Po with the deletion of its own upstream activating sequences) or Pu (the cognate promoter of XylR)::lacZ (the ${\beta}$-galactosidase gene) and transformed into Escherichia coli $DH5{\alpha}$. In the presence of inducers, the biosensor cells immobilized in agarose developed a red color in 1-2 h due to the hydrolysis of chlorophenol red ${\beta}$-D-galactopyranoside (CPRG), a substrate of ${\beta}$-galactosidase that was expressed by the inducers. Among BTEX, high responses were specifically observed with o-, m-, p-chlorotoluene ($0.1{\mu}M-100 mM$) and o-, m-, p-nitrotoluene (0.1 mM-100 mM). Po' demonstrated higher responses than those with Pu. The biosensors immobilized in agarose showed good stability after 21 days' storage at $4^{\circ}C$, and responses in untreated wastewater spiked with chlorotoluene and nitrotoluene, suggesting they can be used to detect compounds in wastewater.

• Environmental Analysis Health and Toxicology
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• v.20 no.2 s.49
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• pp.123-131
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• 2005

본 연구는 GC/MS를 이용하여 수질, 토양 및 저질 시료 중의 4-Nitrotoluene(4-NT)을 분석하는 방법을 확립하고자 하였다. 4-NT은 수질 시료(100mL)에서 n-hexane으로 추출하였으며, 토양 및 저질 시료(10g)에서는 먼저 메탄올로 추출한 후 hexane으로 다시 추출하여 농축시켜 분석하였다. 수질 시료 중의 4-NT의 회수율은 $99.1\%$ 이상이였으며 토양에서의 회수율(recovery)은 약 $110\%$를 보였고 재현성 (relative standard deviation)은 $11.99\%$ 이하였다. 검정곡선은 상관계수$(R^2)$값이 수질과 토양 모두에서 0.994이상의 좋은 직선성을 보여주었다. 본 연구에서 채취한 수질 43개 지역, 토양 35개 지역 및 저질 11개 지역의 모든 시료에서 4-NT은 검출한계 이하로 나타났다. 이 분석방법은 환경 중에 미량으로 존재하는 4-NT의 분석과 모니터링에 유용하게 사용할 수 있는 적합한 방법이라 사료된다.

• Proceedings of the Korean Environmental Health Society Conference
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• 2003.06a
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• pp.199-203
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• 2003

This study was carried out to investigate the removal of 2,4,6-trinitrotoluene, nutrients such as nitrogen, phosphorous compounds in the wetland microcosms. Microcosm study indicated that TNT nutrients were more lastly reduced in the anaerobic condition. The major reductive transformation products included 2,4diamino-6-nitrotoluene (2,4-DANT) 2,6diamino-4-nitrotoluene (2,6-DANT) 4diamino-2,6-nitrotoluene (4-ADNT) 2diamino-4,6-nitrotoluene (2-ADNT). The experimental results for nitrogen removal showed that denitrification kom NO$\sub$3//$\^$-/ to NH$_3$ was dominant process at the bottom of marsh, but nitrification from NH$_3$ to NO$\sub$3//$\^$-/ was dominant on the top of marsh.

• Proceedings of the Korean Environmental Health Society Conference
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• 2004.06a
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• pp.160-164
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• 2004

This study was carried out to investigate the removal of TNT (2,4,6-trinitrotoluene) and parathion in the batch and the continuous constructed wetland microcosms consisting of marsh and pond. The batch system study showed that TNT was almost reduced in the marsh and pond system within 20 days and parathion was within 8 days. The major reductive metabolites of TNT includes 2,4-diamino-6-nitrotoluene (24DANT) >2,6-diamino-4-nitrotoluene (26DANT) >4-diamino-2,6-nitrotoluene(4ADNT) > 2-diamino-4,6-nitrotoluene (2ADNT), and the concentrations of these metabolites were decreased during further operation. The generation rates of 4-nitrophenol, the major metabolite of parathion, were 82% and 15% in the bottom of marsh and pond system, respectively. In the continuous system study, although TNT/parathion degradation pattern was similar to the batch's, marsh-pond system showed the most stable TNT/ parathion removal among various continuous reactor combinations.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.198-205
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• 2005

This study was carried out to investigate the removal of TNT (2,4,6-trinitrotoluene) in the batch and continuous type microcosm systems consisting of marsh and pond. First, the batch reactor study showed that TNT (10 mg/L) was completely removed in the marsh and pond system within 20 days. The major reductive metabolites of TNT include 4-amino-2,6-dinitrotoluene (4-ADNT), 2-amino-4,6-dinitrotoluene (2-ADNT), 2,4-diamino-6-nitrotoluene (2,4-DANT), and 2,6-diamino-4-nitrotoluene (2,6-DANT). These metabolites concentration also decreased during further treatment. The continuous reactor systems combining marsh and pond indicated the similar pattern of TNT degadation and the metabolites production. Among the continuous reactor combinations, marsh-pond system showed more stable TNT removal and metabolites production. The toxicity of the effluent from the continuous system was examined by Microtox Assay using Vibrio fischeri. The result showed that the effluent toxicity was reduced below toxicity endpoint ($EC_{50}$) after continuous marsh pond system, indicating that metabolites of TNT are less toxic than TNT itself. Based on the results, TNT contaminated wastewater can be efficiently treated using marsh and pond wetland systems.

• Korean Journal of Microbiology
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• v.37 no.1
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• pp.66-71
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• 2001

An aerobic microbiological process was tested in 1.5 L stirred tank reactors for the treatment of dinitrotoluenes (DNTs)[e.g., 2.4-dinitrotoluene (2,4-DNT), 2,6-dinitrotoluene (2,6-DNT)] in the test culture of Stenotrophomonas maltophilia, which had previously characterized. Both 2,4-DNT and 2,6-DNT were completely degraded within 10 days and 14 days of incubation, respectively. Addition of the secondary carbon was essential to degrade DNTs, and little degradation was achieved in the absence of the secondary carbons. The effect of additional nitrogens on the degradation of DNTs was evaluated. Complete degradation of DNTs was observed in the absence of any additional nitrogens, whereas DNTs were partially degraded in the growth media with additional nitrogens. Both HPLC and GC-MS were used to detect and verify the residual DNTs and their intermediates. As the results, the HPLC and GC-MS chromatograms demonstrated that the both parent compounds, 2, 4-DNT and 2,6-DNT, and respective intermediates, 2-amino-4-nitrotoluene and 2-amino-6-nitrotoluene, could be successfully identified under the analytical conditions.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2000.12a
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• pp.43-43
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• 2000

• Analytical Science and Technology
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• v.16 no.1
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• pp.59-69
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• 2003

Benzophenone (BZP) and 4-nitrotoluene (4-NT) listed as endocrine disrupting chemicals are suspected to contaminate ground water sites and soil. Analytical method for simultaneous determination of the two chemicals in soil and ground water was developed by gas chromatography-mass spectrometry. Water (100 ml) was extracted with hexane, and soil (10 g) was extracted with methanol and hexane. Recovery in water was >72% for BZP and 90-118% for 4-NT. Recovery for 4-NT and BZP in soil was 51-59% with coefficient variation of less than 19.5%. Calibration curves showed a good linearity with $r^2=0.997$. In water and soil collected at nation-wide sites, BZP was found at 5 sites among 43 water sites at the concentration of $14.87{\pm}3.83ng/100 ml$. No 4-NT was found. It is suggested that this method is appropriate to the simultaneous quantitation of 4-NT and BZP in ground water and soil samples.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.2
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• pp.282-288
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• 2014

In this research, we investigated synthetic method of 2,6-DANT that can be used as a chain extender of urethane/urea and epoxy materials in a demilitarization method via chemical transformations considering environmental, economical aspects and stability of process. We was able to identify through GC monitoring that 2,4-DANT and 2,6-DANT were produced when we inject 'hydrazine monohydrate 3.3 eq. by TNT 1 eq.' with a fine metering pump for 30 minutes and then, reflux for an additional 2 hours. We was able to isolate only 2,6-DANT(99.3% purity and 45.0% yield) from mixture of 2,4-DANT and 2,6-DANT through the separating and refining methods using 2,6-DANT solubility in methanol and crystallinity of 2,6-DANT.

• Environmental Analysis Health and Toxicology
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• v.15 no.1_2
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• pp.45-51
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• 2000

Analytical method of 4-nitrotoluene (4-NT) in water was developed by 9as chromatography/mass selective detector/selected ion monitoring (GC/MSD/SIM). 4-NT was extracted with diethyl ether. Organic layer was washed with 5 % sodium chloride solution. The influence of solvent and evaporation condition on extraction of 4-NT were examined. The retention time of 4-NT peak was 7.72 min. Coefficient of variation (CV) of 4-NT (ng) within day and day-to-day was ranged from 7.0 to 14.6% and from 7.7 to 20.8%, respectively. Recovery of 4-NT was ranged from 84 to 109%, and detection limit of 4-H was lese than 1 ng/㎖.