• Economic and Environmental Geology
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• v.37 no.6 s.169
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• pp.613-629
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• 2004

Contamination of groundwater by volatile organic compounds (VOCs) was investigated for 168 groundwater wells in Ulsan area to study the natural attenuation of organic compounds in the aquifers. As groundwater contamination by VOCs is closely related to land use, 168 groundwater samples were classified into 4 different groups; agricultural, forestry, industrial, and residential & business. From analysis 65 out of 168 groundwater samples contained more than one VOC. Analysis of samples were performed fir 36 halogenated aliphatic hydrocarbons and 25 petroleum hydrocarbons set up by NAWQA of US geological survey. Twelve petroleum hydrocarbons were detected in 26 groundwater wells, but their concentrations were less than 1.5 g/L except for MTBE. Twenty three chlorinated aliphatic hydrocarbons, composed of 11 methanes, 6 ethanes and 6 ethenes, were detected in 63 groundwater samples. The range of methanes concentration was $ND\~330\;/gL,\;ethanes\;ND\~84\;gL$, and PCE and their derivatives $ND\~62\;g/L$. As the study area was comprised of the aerobic/denitrification zones and $Fe^{+3}$ redox condition, most of petroleum hydrocarbons were degraded well, while halogenated hydrocarbons were slowly biodegradation.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.05a
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• pp.141-141
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• 2001

Starvation stimulates multiple signaling pathways, which lead to extensive metabolic alterations Starvation potentiates the hepatotoxicity of a variety of small molecules including chlorinated hydrocarbons and nitrosamines through the induction of CYP2E1. A change in CYF2E1 expression during starvation may also alter the pharmacokinetic profiles of xenobiotics.(omitted)

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.49-52
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• 2001

An experimental study was conducted to test the feasibility of degradative solidification/stabilization (DS/S) process in treating tetrachloroethylene (PCE) in solid phase systems. The Fe(II)-based ds/s process successfully treated PCE in a soil at the reaction rates that would not allow significant release of the contaminant in the environment. A leach model was also developed that could describe the relative importance of leaching and degradation in ds/s. The first and second Damkohler numbers and dimensionless time were important parameters that determined leaching precesses in wastes treated by ds/s.

• Korean Journal of Microbiology
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• v.24 no.4
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• pp.389-393
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• 1986

From the soil and river samples, some bacterial strains degrading chlorinated aromatic hydrocarbons were isolated and identified. Of the isolates, seven strains of Pseudomonas sp. harbouring plasmids were selected for their prominent degradative ability to 2-methyl-4-chlorophenoxyacetic acid. By agarose gel electrophoresis and curing experiment it was found that the genes for 2-methyl-4-chlorophenoxyacetic acid degradaiton were encoded on the plasmids in these selected strains. Antobiotic resistance and degradative ability for other herbicides of the strains were tested.

• Korean Membrane Journal
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• v.1 no.1
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• pp.73-80
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• 1999

The removal of trace chlorinated and aromatic hydrocarbons from water by a pervaporation technique has been carried out through poly (dimethylsiloxane) membrane which had been fabricated by the addition crosslinking reaction. This study dealt with the swelling and permeation behaviors of the PDMS membranes with dichloroethane trichloroethane and toluene aqueous solutions. The swelling ratio in the toluene aqueous solution was much higher than those in the chloroethane solutions at all of the operating temperatures and concentrations. The solubility parameter theory was introduced to interpret the affinity between permeates and a membrane material and in all cases this approach seemed to be proper. It was suggested that the existence of water clusters in the membrane due to the hydrophobic characteristics of the membrane made the size of the permeating water larger resulting in suppressing water permeation and increasing enrichment of the organic components. The permeation behaviors at different membrane thicknesses were indirectly interpreted in terms of the effect of concentration polarization.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.66-69
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• 1998

1. 서론 : 본 연구는 시간이 경과함에 따라 free volume감소로 나타나는 PTMSP[Poly(1-trimethylsilyl-1-propyne)] memebrane의 pysical aging을 늦추거나 방지할 목적으로 PTMSP polymer를 합성하여 여기에 hydroxy-terminated PDMS를 graft시켜 PTMSP/PDMS graft copolymer를 제조하였다. 용매증발법에 의해 PTMSP memebrane 및 PTMSP/PDMS graft copolymer memebrane을 제막한 후 PTMSP막의 물리적 노화를 관찰하기 위한 시점에서 조업시간에 따른 이들 막의 transport property을 살펴 보았다. 또한 이들 polymer을 사용하여 0.5 wt%의 희박 dope solution을 제조한 후 여기에 상전환법에 의해 제조된 비대칭 PEI(polyetherimide)지지막을 dip-doping시켜 PTMSP-PEI, PTMSP/PDMS-PEI 복합막을 제조하여 상기의 두 막과 투과증발 특성을 상호 비교하여 보았다. 그리고 객관적 비교 자료를 얻을 목적으로 PDMS막과 PDMS-PEI 복합막을 각각 제막하여 동일조건에서 실험을 수행하였다. 따라서 본 연구는 수중에 미량 용해된 chloroform, trichloroethylene, perchlororthylene, 1,1,1-trichloroethane 등의 유기염소계화합물 제거 실험을 통해 PTMSP, PTMSP/PDMS 등의 dense membrane과 asymmetric composite membrane 사이의 상관관계 및 이들 막들의 투과특성을 서로 비교, 분석하는데 목적을 두었다.

• Microbiology and Biotechnology Letters
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• v.34 no.3
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• pp.185-195
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• 2006

Phytoremediation is an economical and environmentally friendly bioremediation technique using plants which can increase the microbial population in soil. Unlike other pollutants such as heavy metals, poly-chlorinated biphenyl, trichloroethylene, perchloroethylene and so on, petroleum hydrocarbons are relatively easily degradable by soil microbes. For successful phytoremediation of soil contaminated with petroleum hydrocarbons, it is important to select plants with high removal efficiency through microbial degradation. In this study, we clarified the roles of plants and rhizobacteria and identified their species effective on phytore-mediation by reviewing the papers previously reported. Plants and rhizobacteria can degrade and remove the petroleum hydrocarbons directly and indirectly by stimulating each other's degradation activity. The preferred plant species are alfalfa, ryegrass, tall fescue, poplar, corn, etc. The microorganisms with a potential to degrade hydrocarbons mostly belong to Pseudomonas spp., Bacillus spp., and Alcaligenes spp. It has been reported that the elimination efficiency of hydrocarbons by soil microorganisms can be improved when plants were simultaneously applied. For more efficient restoration, it's necessary to understand the plant-rhizobacteria interaction and to select the suitable plant and microorganism species.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.188-191
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• 2003

Sing]e-well-push-pull tests were developed for use in assessing the feasibility of in-situ aerobic cometabolism of chlorinated aliphatic hydrocarbons (CAHs). The series includes Transport tests, Biostimulation tests, and Activity tests. Transport tests are conducted to evaluate the mobility of solutes used in subsequent tests. These included bromide or chloride (conservative tracers), propane (growth substrate), ethylene, propylene (CAH surrogates), dissolved oxygen (electron acceptor) and nitrate (a minor nutrient). Tests were conducted at an experimental well field of Oregon State University. At this site, extraction phase breakthrough curves for all solutes were similar, indicating apparent conservative transport of the dissolved gases and nitrate prior to biostimulation. Biostimulation tests were conducted to stimulate propane-utilizing activity of indigenous microorganisms and consisted of sequential injections of site groundwater containing dissolved propane and oxygen. Biostimulation was detected by the increase in rates of propane and oxygen utilization after each injection. Activity tests were conducted to quantify rates of substrate utilization and to confirm that CAH-transforming activity had been stimulated. In particular, the transformation of injected CAH surrogates ethylene and propylene to the cometabolic byproducts ethylene oxide and propylene oxide provided evidence that activity of the monooxygenase enzyme system, responsible for aerobic cometabolic transformations of CAHs had been stimulated. Estimated zero-order transformation rates decreased in the order propane > ethylene > propylene. The series of push-pu3l tests developed and field tested in this study should prove useful for conducting rapid, low-cost feasibility assessments for in situ aerobic cometabolism of CAHs.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.10
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• pp.575-580
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• 2017

Chlorinated hydrocarbons (TCE and PCE), petroleum hydrocarbons (BTEX, PAHs, and TPH), and explosive compounds (TNT, RDX, and HMX) have been detected in underground water countrywide. The overall objective of this study is to evaluate sono-catalytic degradation coupled with the use of PUV in order to understand the fate and transport of a representative selection of non-biodegradable contaminants (i.e., TCE, PCE, BTEX, PAHs, TPH, TNT, RDX, and HMX) in groundwater. Both ultraviolet (UV) and ultrasound (US) systems are used in degrading of organic contaminants and they can thus be applicable simultaneously as an UV/US hybrid system in attempts further to increase the degradation efficiency. Results indicate that synergistic effect of UV/US hybrid system is closely correlated to the enhancement of sono-chemical reactivity with the UV-US interaction of increasing the formation rate of OH by providing additional $H_2O_2$ production through the pyrolysis of water molecules during UV/US hybrid irradiation.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.1
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• pp.47-51
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• 2000

2,4,5-trichlorophenoxyacetic acid (2,4,5-T)-degrading bacterial strains were isolated from rice field and field in suburbs of Taejon. Of the total 100 isolates, 19 strains were selected by fast growth on solid minimal media containing 2,4,5-T as a sole of carbon and energy, and they were identified to genus level. 11 strains were identified as Pseudomonas, 4 strains as Acinetobacter, 1 strains were as Alcaliagenes and 3 strains were not identified. Strains MU19 and MU92 which were identified as Pseudomonas were capable of degradation for 4 kinds of chlorinated aromatic hydrocarbons, 2,4-D, 2,4,5-T, MCPA and 3CB. Acinetobacter sp. MU38 showed the highest degradability in liquid minimal media at 48 hours after inoculation, and Pseudomonas spp. MU19. MU57, MU73, and MU92 were able to degrade carbon source at higher rates. As the results Acinetobacter sp. MU38 and Pseudomonas spp. MU19 and MU92 were capable of biodegradation for broad range of halogenated aromatic hydrocarbons, and had higher rates of degradation for 2,4,5-T.