• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2002년도 추계국제학술대회
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• pp.171-171
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• 2002

Recent industrial society has human widely exposed to PAHs that are comming from the incomplete combustion of organic material as widerspread environmetal contaminants. Biological activities of PAHs are not known although PAHs are considered as carcinogens. PAHs in the mammalian cells affect CYP1A1 gene expression as well as other phase II drug metabolizing enzymes as UDPGT, NMOR etc. The mechanism of action of PAHs has been studied extensively, however it is not clear how PAHs turn on CYP1A1 in human breast cancer. Our labolatory have been studied the effect of PAHs in the human breast cancer cell lind MCF7. In this study, we examined the ZR-75-1 human breast cancer cells as a new system to evaluate bioactivity of PAHs. ZR-75-1 human breast cancer cell line has been estabilished from the breast cnacer patient, has estrogen receptors and progesteron receptors. We have been able to estbilish long term culture system of this cells then used for the study to observe the effect of PAHs. We demonstrate that PAHs induced the transcription of an aryl hydrocarbon-responsive reporter vector containing the CYP1A1 promoter and 7-ethoxyresolufin O-deethylase(EROD) activity of CYP1A1 enzyme in a concentration-dependant manner. RT-PCR analysises indicated that PAHs significantly up-regulate the constitutive level of CYP1A1 mRNA. Apparently, ZR-75-1 cells have Aryl hydrocarbon recetors, therefore it would be good experimental tool to study the cross-talk between PAHs and steroid actions.

• 한국물환경학회지
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• 제36권4호
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• pp.314-321
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• 2020

This study evaluated the applicability of UV-AOP process using medium-pressure UV lamp and H₂O₂ to remove TOC and emerging micropollutants in the effluent from a sewage treatment plant. The UV lamp with higher output(1.6~8.0 kW) showed slightly higher amount of power in removing TOC of 1 mg/L(0.09 kWh/mg/L~0.11 kWh/mg/L), however it was found that there was no significant difference for each cases. In addition, under the condition that the H₂O₂ concentration is sufficient, as the power consumption of the UV lamp increases, the unit TOC removal concentration per unit H₂O₂ decomposition concentration also increases, resulting in effective removal of TOC. The removal rate of 7 new trace contaminants, such as antibiotics by the UV-AOP tested, was at least 89.4%, and the ability to remove the emerging micro pollutants in the process was very effective. But, it was judged that it could not be excluded that the probablity of transforming to oxidated by-product in the case of a low TOC removal efficiency. Depending on the operating conditions of the UV and H₂O₂ processes, a higher BOD concentration is found in the treated water than in the influent, and it is necessary to review the UV power and proper injection conditions of H₂O₂ to maintain the BOD concentration increase below a certain level.

• 한국물환경학회지
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• 제25권4호
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• pp.522-529
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• 2009

To supply safe drinking water to areas lacking in water supply and drainage system, such as rural area and military bases in proximity to Demilitarized Zone, effective method for treating organic contaminants such as MTBE is required. This study focuses on seeking optimal conditions for effective degradation of MTBE using a bath type ultrasound reactor. Effectiveness of MTBE degradation by ultrasound is dependent on the frequency, power, temperature, treatment volume, initial concentration, catalyst, etc. In this study the degradation rate of MTBE by ultrasound was proportional to power/unit volume ratio and removal is relatively more efficient for 0.1 mM than for 1 mM of MTBE solution. Efficiency of ultrasound treatment for 1 mM MTBE solution was enhanced under bath temperature of $30^{\circ}C$ compared to $4^{\circ}C$, but the temperature effect was negligible for 0.1 mM MTBE solution. Also for 0.1 mM MTBE solution, effect of catalyst such as $TiO_2$ and $Fe^0$ on treatment speed was negligible, and zeolite even increases the time taken for the degradation. Under these specific experimental conditions of this study, the most determinant factor for degradation rate of MTBE in solution was frequency and power of ultrasound. The results have shown that a continuous ultrasound reactor system can be used for small scale remediation of organically polluted groundwater, under optimal conditions.

• 생태와환경
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• 제48권1호
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• pp.12-25
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• 2015

The tributaries of Daechung Lake play an important role in controlling eutrophication in the lake, which is used for agricultural purposes and as potable water. However, water quality properties were not extensively studied in the tributaries of Daechung Lake. The objectives of this study are to investigate spatial and temporal properties of water quality and to characterize streams which could threaten water quality of Daechung Lake. For this study, water samples were weekly or monthly collected from February 2014 to October 2014 in 9 streams. Water quality parameters analyzed in this study include biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), total nitrogen and phosphorus (TN and TP), suspended solids (SS), and chlorophyll a. Based on temporal distribution and principal component analysis, BOD, COD, TOC, SS, and TP were controlled by not only river discharge that increased during summer due to heavy rain fall, but also due to anthropogenic input (e.g., bridge construction and/or agricultural activity). Dilution is also one of the factors explaining TN and conductivity, both of which decreased with increased discharge. Generally, concentrations of contaminants (BOD, COD, TOC, TN and TP) in the tributaries were higher than those of Daechung Lake. However, pollution load indicated that only the main channel of Geum River and Sook Stream may largely influence lake waters, attributed mostly to their large volumes. This implies that the main channel and Sook Stream are the major influences on the water quality of Daechung Lake.

• 대한화학회지
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• 제47권6호
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• pp.608-613
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• 2003

Post-Oxide CMP(Chemical-Mechanical Polishing) 결과 실리콘 웨이퍼를 오염 시키고 있는 슬러리 입자의 세정 가능성을 조사하기 위하여DHF(Diluted HF)에 비이온성 계면 활성제인 PAAE(Polyoxyethylene Alkyl Aryl Ether), 비양성자성 용제인 DMSO(Dimethylsulfoxide) 와 초순수의 혼합물인 새로운 세정액을 제조하였다. 세정력을 평가하기 위해서 세정제 내에서 각각 다른 제타 포텐셜을 갖는 실리카($SiO_2$), 알루미나($Al_2O_3$)와 PSL(polystylene latex) 입자를 실리콘 웨이퍼 표면의 산화막에 인위적으로 오염시킨 후 실험에 이용하였다. 초음파하에서 세정액의 성능 평가 결과 본 세정기술은 효과적인 입자의 세정능력과 금속이온에 대한 세정 능력을 나타내고 있음을 확인하였다. 즉 기존의 APM($NH_4OH,\;H_2O_2$와 D.I.W의 혼합물)과 달리 상온에서 세정이 가능하고 세정과정이 단축 되었으며, 낮은 농도의 HF를 사용함으로써 최소의 에칭에 의하여 표면 거칠기를 감소시킬 수 있음을 보여주고 있다. 또한 주요 CMP 금속 배선 물질들에 대한 낮은 부식력으로 기존의 CMP 후 세정공정에 뿐만 아니라 차세대CMP 공정으로 각광 받고 있는 Copper CMP 에 대한 Brush 세정 공정의 보조 세정제로 본 세정제가 적용될 가능성이 있음을 확인하였다.

• 한국물환경학회지
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• 제24권1호
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• pp.19-29
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• 2008

Hot air sparging is a groundwater remediation technique, in which organic contaminants volatilized into hot air from the saturated to vadose zone. In the laboratory diesel (10,000 mg TPH/kg) was spiked in contaminated saturated aquifer soil. The hot air ($34.9{\pm}2.7^{\circ}C$) was injected in intermittent (Q=1,500 mL/min, 10 minute injection and 10 minute idle) modes. We performed microcosm tests using the groundwater samples to assess TPH reductive remediation activity. For Terminal-Restriction Fragment Length Polymorphism (T-RFLP) analysis of eubacterial communities in sludge of wastewater treatment plants and soil of experiment site, the 16S rDNA was amplified by Polymerase Chain Reaction (PCR) from the sludge and the soil. The obtained 16S rDNA fragments were digested with Msp I and separated by electrophoresis gel. We found various sequence types for hot air sparging experiment with sludge soil samples that were closely related to Bacillus (149 bp, Firmicutes), Methlobacterium (149 bp, Euryarchaeotes), Pseudomonas (492 bp, ${\gamma}$-Proteobacteria), etc., in the clone library. In this study we find that TPH-water was reduced to 78.9% of the initial value in this experiment aquifer. The results of the present study suggests that T-RFLP method may be applied as a useful tool for the monitoring in the TPH contaminated soil fate of microorganisms in natural microbial community.

• 대한환경공학회지
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• 제31권2호
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• pp.102-108
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• 2009

연속회분식반응기에서 측정되는 기초상용계측기의 프로파일은 공정 내에서 수행되는 유기오염물질 및 영양염류 제거반응의 진행 정도에 대한 정보를 제공할 수 있다. 특히 호기성 반응구간에 측정되는 pH나 DO, ORP의 변곡점 등의 정보를 이용한 반응 종료 감지는 널리 알려진 응용사례라고 할 수 있다. 그러나 이러한 정보들은 반응의 종료 여부에 대한 정보를 제공할 뿐, 현재 공정에 가해지는 부하에 대한 정보를 제공하지는 못한다. 본 논문에서는 운전자에게 공정 유입수 내의 호기적 반응을 요하는 부하, 즉 암모니아 부하 및 유기물 부하의 고/중/저에 관한 정보를 제공할 수 있는 기초상용계측기의 정보를 활용한 진단 알고리즘을 개발하였다. 본 알고리즘으로 인해, 연속회분식반응기를 운전할 시에 수시로 변화하는 유입수의 부하를 습식분석 없이 자동 계측기 프로파일로부터 얻어낼 수 있을 것으로 사료된다.

• The Journal of Advanced Prosthodontics
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• 제7권2호
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• pp.151-159
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• 2015

PURPOSE. To describe and characterize the surface topography and cleanliness of CAD/CAM manufactured zirconia abutments after steaming and ultrasonic cleaning. MATERIALS AND METHODS. A total of 12 ceramic CAD/CAM implant abutments of various manufacturers were produced and randomly divided into two groups of six samples each (control and test group). Four two-piece hybrid abutments and two one-piece abutments made of zirconium-dioxide were assessed per each group. In the control group, cleaning by steam was performed. The test group underwent an ultrasonic cleaning procedure with acetone, ethyl alcohol and antibacterial solution. Groups were subjected to scanning electron microscope (SEM) analysis and Energy-dispersive X-ray spectroscopy (EDX) to verify and characterize contaminant chemical characterization non- quantitatively. RESULTS. All zirconia CAD/CAM abutments in the present study displayed production-induced wear particles, debris as well as organic and inorganic contaminants. The abutments of the test group showed reduction of surface contamination after undergoing an ultrasonic cleaning procedure. However, an absolute removal of pollutants could not be achieved. CONCLUSION. The presence of debris on the transmucosal surface of CAD/CAM zirconia abutments of various manufacturers was confirmed. Within the limits of the study design, the results suggest that a defined ultrasonic cleaning process can be advantageously employed to reduce such debris, thus, supposedly enhancing soft tissue healing. Although the adverse long-term influence of abutment contamination on the biological stability of peri-implant tissues has been evidenced, a standardized and validated polishing and cleaning protocol still has to be implemented.

• 한국지반신소재학회논문집
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• 제5권2호
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• pp.17-22
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• 2006

비위생매립지(非衛生埋立地)의 설치는 매립지 주변의 지반오염에 심각한 영향을 미친다. 동전기정화기법(動電氣淨化技法, Eelectrokinetic Remediation Technology)은 주로 무기오염물질에 의해 오염된 저투수성(低透水性)지반의 정화에, 투수성반응벽체(透水性反應壁體, Permeable Reactive Barrier)는 주로 지하수 내의 유기오염물질의 분해 등에 각각 효과적이다. 본 연구에서는 동전기정화기법과 투수성반응벽체의 장점을 복합적으로 비위생매립지 주변의 오염현장에 적용하여 정화효과를 조사하였다. 환경오염원이자 폐기물인 제강슬래그를 재활용한 오토마이징슬래그(Atomizing Slag)를 투수성반응벽체의 반응물질로 이용하였다. 현장적용 실험결과, 동전기정화기법과 투수성반응벽체의 장점을 복합적으로 적용한 EK & PRB System(EPS)이 원위치(原位置, In-Situ) 정화효율을 높여줌을 알 수 있었다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1999년도 정기총회 및 춘계 공동 학술발표회
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• pp.149-156
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• 1999

In the United States (U.S.), the monitored natural attenuation (MNA) approach has been used as an alternative remedial option for organic and inorganic compounds retained in soil and dissolved in groundwater. The U.S. Environmental Protection Agency (EPA) defines the MNA as“in-situ naturally-occurring processes include biodegradation, diffusion, dilution, sorption, volatilization, and/or chemical and biochemical stabilization of contaminants and reduce contaminant toxicity, mobility or volume to the levels that are protective of human health and the environment”. The Department of Soil Environment. National Institute Environmental Research (NIER) is in the process for demonstrating the MNA approach as a potential remedial option for the BTEX contaminated site in Uiwang City. The project is charactering the research site in terms of the nature and extend of contamination, biological degradation rate, and geochemical and hydrological properties. The microbial-degradation rate and effectiveness of nutrient and redox supplements will be determined through laboratory batch and column tests. The geochemical process will be monitored for determining the concentration changes of chemical species involved in the electron transfer processes that include methanogenesis, sulfate and iron reduction, denitrification, and aerobic respiration. Through field works, critical soil and hydrogeologic parameters will be acquired to simulate the effects of dispersion, advection, sorption, and biodegradation on the fate and transport of the dissolved-phase BTEX plume using Bioplume III model. The objectives of this multi-years research project are (1) to evaluate the MNA approach using the BTEX contaminated site in Uiwang City, (2) to establish a standard protocol for future application of the approach, (3) to investigate applicability of the passive approach as a secondary treatment remedy after active treatments. In this presentation, the overall picture and philosophy behind the MNA approach will be reviewed. Detailed discussions of the site characterization/monitoring plans and risk-based decision-making processes for the demonstration site will be included.