• Ocean Science Journal
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• 제41권1호
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• pp.43-51
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• 2006

Concentration and distribution of Fe, Zn, Cu, Cd, Mn, Pb, Ni among subcellular fractions (cellular membrane structures and cytosol) and Zn, Cu, Cd among cytoplasmic proteins in the kidney and digestive gland of mussel Modiolus modiolus living along a polymetallic concentration gradient were studied. It was found in the kidney of M. modiolus from contaminated sites that the Fe percent increased in the "membrane" fraction, whereas Zn, Pb, Ni and Mn percent increased in the cytosol compared to the kidney of the control mussel. Note kidney cytosol of M. modiolus from clean and contaminated sites sequestered major parts of Cu and Cd. In the digestive gland of M. modiolus from contaminated sites Fe, Zn, Cd, Mn, Ni percent increased in the "membrane" fraction, whereas Cu, Pb percent increased in the cytosol compared to digestive gland of control mussel. Gel-filtration chromatography shows kidney of M. modiolus contains increased metallothionein-like protein levels irrespective of ambient dissolved metal concentrations. It was shown that the metal detoxification system in the kidney and digestive gland of M. modiolus was efficient under extremely high ambient metal levels. However, under complex environmental contamination in the kidney of M. modiolus, the metal detoxification capacity of metallothionein-like proteins was damaged.

• 한국식품위생안전성학회지
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• 제20권1호
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• pp.43-47
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• 2005

본 연구는 신선채소류의 대형매장과 재래시장에서의 청결도를 비교하기 위하여 시중에 유통 중인 상추, 깻잎, 오이를 서울과 경기남부의 15개 대형매장과 21개 재래시장에서 sampling하여 총호기성균, 대장균군, Escherichia coli 및 Listeria monocytogenes의 오염도 수준을 평가하였다. 대형매장과 재래시장에서의 상추, 깻잎, 오이의 총호기성균과 대장균군의 오염도는 유의차가 없었다(p>0,05).그러나 3가지 채소에서의 총호기성균 오염수준은 상추, 깻잎, 오이 순으로 나타났으며 그 수준은 각각 평균 $7.01{\pm}0.14\;log_{10}CFU/g$(대형)과 $7.10{\pm}0.11\;log_{10}CFU/g$(재래), $6.69{\pm}0.20\;log_{10}CFU/g$(대형)과 $6.44{\pm}0.13\;log_{10}CFU/g$(재래), $5.37{\pm}0.25\;log_{10}CFU/g$(대형)과 $5.27{\pm}0.19\;log_{10}CFU/g$(재래)이었으며 대장균군의 오염 순위 또한 같은 양상을 보였다. E. coli 검출률 역시 3가지 채소 모두에서 매장간의 유의적 차이는 없었으며(p>0.05) 상추와 깻잎은 대형매장과 재래시장 모두에서 $30\%$ 이상의 빈도로 검출되었으나, 오이에서는 $10\%$ 미만의 검출빈도를 보였다. L. monocytogenes는 모든 채소에서 검출되지 않았다(ND: 오이 <3 CFU/g, 상추, 깻잎<10 CFU/g). 따라서 본 연구에서 측정된 오염수준은 신선채소류의 미생물 위해평가(MRA)프로그램 개발의 기초자료로 활용될 수 있을 것이다.

• 한국식품위생안전성학회지
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• 제27권2호
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• pp.161-168
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• 2012

떡은 수분활성도, pH, 보관온도 등이 미생물 증식에 적합하고 구입 후 별도 조리과정 없이 그대로 섭취하는 식품으로 미생물학적 안전문제를 자주 야기하고 있다. 본 연구는 국내 유통 떡에 문제시되는 미생물학적 위해요인을 제조공정별로 파악하고 그 위생관리 개선방안을 도출하고자 하였다. 3가지 떡 (시루떡, 가래떡, 경단)을 선정하여 원료, 제조공정 및 제조환경에 대한 미생물 오염도 분석을 실시하였다. 8가지 원재료의 오염도 분석결과 일반세균 2.5~4.5, 대장균군 ND~1.9, 진균수 1.2~2.1, B. cereus 1.0~2.1 log CFU/g수준으로 검출되었으며 E. coli, S. aureus, C. perfringens는 검출되지 않았다. 떡의 제조공정별 오염도 분석결과 원료의 불림 분쇄 공정에서 일반세균, 대장균군, 진균, B. cereus의 오염도가 증가하나 증자 후 감소하여 완제품에서 일반세균은 2.2~3.7, 대장균군 ND~1.8 log CFU/g 수준으로 나타났다. 제조환경의 미생물학적 오염도 분석결과 전처리실의 쌀분쇄기, 냉각수조, 펀칭기 등의 설비에서 오염수준이 높게 나타났으며, 전처리실 작업자의 개인 위생이 미흡한 것으로 나타났다. 작업장 공기 오염도 분석결과 청결구역 3곳에서 일반세균 34~46, 대장균군 2.5~7.0, 진균수 14~30 $CFU/plate{\cdot}5min$ 검출되어 권장 낙하세균기준을 초과하는 것으로 나타났다. 본 연구결과 떡의 원재료 및 완제품의 미생물학적 오염수준은 안전하나 제조환경의 오염도는 문제시되는 것으로 나타나 제품의 교차오염 가능성을 내포하고 있는 것으로 사료된다. 따라서 제조 설비 및 표면시설에 대한 체계적인 세척 및 소독을 실시하여 미생물학적 위해를 감소하고 작업자 위생 관리 교육 프로그램을 선행하여 작업자 개인의 위생 수준 향상, 작업장 내 공기중의 미생물 관리가 함께 이루어지도록 하는 것이 필요한 것으로 여겨진다.

• KEPCO Journal on Electric Power and Energy
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• 제7권2호
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• pp.317-321
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• 2021

As the large-scale renewable energy power plant increases, the high-capacity and compact Energy Storage System (ESS) is required. However, this trend could reduce the insulation reliability of ESS. In this study, the surface flashover characteristics for four types of solid insulators are investigated in the uniform electric field with AC and Lightning Impulse (LI) voltage waveforms under various contamination levels. In addtion, insulator surfaces are compared based on the contact angle before and after surface flashover. The experimental results show that AC flashover voltage is dependent on the materials and the contamination level, but LI flashover voltage is only associated with the contamination level. Especially, AC flashover voltage of PC (PolyCarbonate) is higher than that of other insulators, which is associated with the unique and sequential creepage discharge propagation pattern of PC. The localized discharges on the surface of PC form corresponding tracking points. Then, the interconnected trackings result in the complete flashover. This flashover patterns degrade the surface of PC much more than that of epoxy and Bulk Molding Compoud (BMC). Thus, the contact angle of PC is significantly reduced compared to that of other insulators. The increased hydrophilicity in the surface of PC enhances the insulator surface conductivity.

• 한국환경과학회지
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• 제15권3호
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• pp.229-236
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• 2006

Organophosphorus pesticides (OPPs) contents in the sewage sludge derived from the residential and industrial areas were determined in order to characterize contemporary organic contamination levels as a part of the ongoing development of the environmentally sound sewage sludge management strategy in Korea. OPPs were extracted from freeze-dried sludges in a ultrasonic extractor. The extracts were cleaned-up by florisil column and subsequently fed into gas chromatograph/nitrogen phosphorus detector (GC/NPD) for determining OPP contents. Diazinon, dimethoate, disulfoton, EPN, malathion, methyl parathion, parathion, phorate and sulfotep were present in the appreciable amount in the domestic sewage sludges. The sum of the 9 OPPs in the sewage sludge varied from 534.8 to 15552.1 ${\mu}g/kg$, dry wt..

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.401-406
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• 2000

Spilling of petroleum hydrocarbons such as gasoline, motor oils, and diesel fuel from underground storage tanks (USTs) is a major source of contamination to ground water and soils. In response to the need of developing an effective and economical cleanup technique, this study investigates the effectiveness of using sonication to enhance the soil flushing method. The study involves laboratory testing, and the testing was conducted using a specially designed and fabricated device to determine the effect of sonication on contaminant removal. The sonication was applied at 20 kHz frequency under different power levels. Test soil was Joomoonjin Sand, and diesel fuel was used as a contaminant of soil flushing test. The results of the investigation show that sonication enhanced the contaminant removal from soils significantly, and the degree of enhancement varied with power levels of sonication. Based on the results of the study, it is concluded that the flushing method with sonication has a great potential to become an effective method for removing petroleum hydrocarbons from the contaminated ground.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.115-119
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• 2003

Pollutants from industry, mining, agriculture, and other sources have contaminated sediments in many surface water bodies. Sediment contamination poses a severe threat to human health and environment because many toxic contaminants that are barely detectable in the water body can accumulate in sediment at much higher levels, the purpose of this study was to make convenient sampling method and optimal treatment of sediment for water quality improvement in reservoir or stream based on an evaluation of degree of contamination. Results for analysis of S-reservoir sediments were observed that copper concentration of almost areas were higher than the regulation of soil pollution (50 mg/1) for the riverbed. S-stream sediments were observed that copper, arsenic and TPH concentration of almost areas were exceeded soil pollution concerning levels for factorial areas. We used Remscreen(version. 1.0) program which is contaminated soil recovery program to select optimal treatment method of contaminant sediments. The result was shown in the order of Thermal Calcination > Excavation, Retrieval and Off-site Disposal(comparative less then contaminant) > Low Temperature Thermal Desorption + Solidification/Stabilization.

• 자원환경지질
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• 제32권1호
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• pp.63-72
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• 1999

In order to examine the contamination levels of trace elements in stream sediments in the Chungnam coal mine area, stream sediment and water samples were collected and analyzed for trace elements. The pH of stream water was neutral or weak-alkaline and the mobility of metal in stream sediments was supposed to be low. From the result of cluster analysis, non-polluted sampling stations can be distinguished from polluted sampling stations influenced by mining activities. The trace element concentrations in sediments from non-polluted zone were considered to be the natural backround concentrations of this area. The trace element concentrations in sediment samples from the mining area were higher than those from non-polluted area, and contaminated area of enriched trace element levels need to be properly managed. From the results of discriminant and regression analyses, concentrations of Cd, Cu, Pb AND zN and predicted values of Be, Mo, and Ni in Chungnam coal mine area were found to be lower than those in metal mining areas in Korea.

• 한국식품위생안전성학회지
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• 제15권3호
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• pp.204-208
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• 2000

1996년 3월부터 1998년 10월간에 경남지방의 시판 냉장 및 냉동우육 350건,돈육 338건 및 계육 350건으로부터 최확수법(MPN)을 이용하여 식중독균의 오염수준을 조사하였다. Staphylococcus aureus의 경우 10∼10,000 CFU/8으로 비교적 높은 오염수준은 나타내었고, Salmonella 및 Listeria monocytogenes는 0,9 MPN/g 이하였으며, Campylobacter jejunilcoli는 7.0 MPN/g (cm2)이하였다. 분리된 4종류의 병원세균에 대하여 냉장우육의 14.3%,돈육의 25.3% 및 계육의 55.0%가 1종류에, 그리고 우육 2.7%,돈육 5.6% 및 계육의 14.7%가 2종류에, 돈육의 2.4%가 3종류의 병원세균에 교차오염 되어있었다. 일반적으로 병원세균은 냉장계육에서 보다 냉동 포장계육에서 더 높은 분리 빈도를 나타내었다.

• 환경영향평가
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• 제14권2호
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• pp.83-96
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• 2005

Brominated flame retardants have the market share of 40%, comparing others because of their low cost and highly effective retardation against the flame. However, their toxic effects in human and properties of the accumulation in the environments have been issued among the international organization such as EU, OECD and etc. It, therefore, was surveyed the classification, toxic effects, and the usage of Brominated flame retardants, the trends for their managements in the world and Korea, and their contaminated levels in Korean Peninsula. In addition, the management directions for them were proposed. Penta, octa, and deca-BDE among brominated retardants will seem to be prohibited by the regulation as a flame retardants for plastics in Europe because of their toxic effects. Although Penta and Octa BDEs was used marginally in Korea, deca-BDE was 27% of brominated flame retardants (49,050 ton) which had been used in 2002. However, risk assessment for brominated retardants might not launched in Korea, yet. These reports demonstrate that toxic brominated retardants such as PBDEs will be assessed for their usage and the level of contamination in the environment in the area of the point sources like the industrial areas, incinerators and etc. However, the law to regulate the hazardous chemicals seems not to be dictated the monitoring of their contamination in the environment. We, therefore, suggest how to evaluate and to monitor the toxic contaminants with EIA (Environmental Impact Assessment) and LCA (Life Cycle Assessment) system. Further, to establish the management system of BFRs (such as the monitering of contamination levels in environments, life cycle assessment, and risk assessment for the toxic chemicals), It can be recommended the law to deal with the method analyzing chemicals will be established, which contains QA/QC (Quality Assurance and Quality Control) to evaluate the analytic capability of the companies to prepare EIS (Environment Impact Statement) or other institutes for analyzing chemicals.