• 대한환경공학회지
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• 제31권2호
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• pp.125-131
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• 2009

영가철과 혐기성 미생물을 이용한 환원적 탈염화반응을 통한 다이옥신 처리 능력을 평가하기 위해, 자유에너지 선형관계(linear free energy relationship)를 이용하여 다이옥신의 탈염화에 의한 농도 및 독성변화 예측 모델을 최초로 정립하였다. 수용액상에 존재하는 다이옥신류의 깁스자유에너지는 기존 문헌의 열역학적 계산결과를 범밀도함수이론(density functional theory)을 이용한 계산 수준으로 보정하였으며, 보정된 깁스자유에너지와 실험을 통해 얻은 탈염화 반응속도 상수와의 선형관계를 통해 다이옥신의 탈염화 반응 256개에 대한 반응속도상수를 예측하였다. 본 모델을 통해 탈염화에 의해 변화하는 다이옥신 류 76종에 대한 시간 별 농도를 계산할 수 있다. 8염화다이옥신(Octachlorinated dibenzo-p-dioxin, OCDD)이 완전히탈염화되어 dibenzo-p-dioxin (DD)로 탈염화되기까지는 100년 이상의 반응시간이 필요하였으며, 독성등가값(toxic equivalent quantity, TEQ)의 경우 탈염화가 진행되면서 초기농도의 10배 이상까지 증가하는 것으로 밝혀졌다. 이를 통해, 다이옥신의 처리를 위해서는 좀 더 빠른 탈염화 반응속도를 갖는 다른 전자공여 시스템을 사용하거나, 환원적 탈염화-라디칼 산화와 같은 복합 연계처리가 필요함을 알 수 있다. 본 논문을 통해 제시된 예측 기법은 다이옥신뿐 아니라 다른 할로겐화 화합물의 탈염화 예측과 여러 전자공여 시스템에 대한 평가에 적용이 가능하다.

• 한국환경보건학회지
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• 제33권1호
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• pp.11-15
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• 2007

This study was performed to evaluate the congeners of polychlorinated dibenzo-p-dioxins(PCDDS) and polychlorinated dibenzofurans(PCDFs) in Korean foods among children in Korea, in comparison with the findings in their mothers. The PCDDs and PCDFs intakes of 24-h diet duplicates were estimated from the previous Korean reports. In Korean children and their mothers of this study, major sources of lipid intake were plant-based foods(62% for children, 66% for their mothers). The women took 34% of lipid from animal sources, among which meats were leading sources of animal lipids(30%). Fish and shellfish were accounted for 4% in total lipid intake. Daily intake of PCDDs and PCDFs in the children md their mothers were 0.002-3.188 and 0.002-2.717 pg WHO-TEQ/day in animal sources and ND-0.283 and ND-0.296 pg WHO-TEQ/day in plant sources, respectively. PCDDs/PCDFs intake from animal origin was the major exposure source for both children and their mothers in Korea. Among the 17 PCDD/Fs congeners, 2,3,4,7,8-pentachlorodibenzofuran was assumed to be the effective exposure marker for diet intake.

• Bulletin of the Korean Chemical Society
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• 제20권6호
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• pp.689-695
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• 1999

Supercritical fluid extraction (SFE), ultrasonic extraction (USE), and accelerated solvent extraction (ASE) were compared with the well known Soxhlet extraction for the extraction of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins(PCDDs) from the XAD-2 resin which was used to adsorb PCDDs in the atmosphere. XAD-2 resin spiked with five PCDDs was chosen as a sample. The optimum conditions for the extraction of PCDDs by SFE were turned out to be the use of CO2 modified with 10% toluene at 100 ℃ and 350 atm, with 5 min static extraction followed by 20 min dynamic extraction. SFE gave a good extraction rate with good reproducibility for PCDDs ranging from 68 to 98%. The ultrasonic extraction of PCDDs from XAD-2 was investigated and compared with other extractions. A probe type method was compared with a bath type. Two extraction solvents, toluene and acetone were compared with their mixture. The use of their mixture in probe type, with 9 minutes of extraction time, was found to be the optimum condition. The average recovery of the five PCDDs for USE was 82-93%. Accelerated solvent extraction (ASE) with a liquid solvent, a new technique for sample preparation, was performed under elevated temperatures and pressures. The effect of tem-perature on the efficiency of ASE was investigated. The extraction time for a 10 g sample was less than 15 min, when the organic solvent was n-hexaneacetone mixture (1 : 1, v/v). Using ASE, the average recoveries of five PCDDs ranged from 90 to 103%. SFE, USE, and ASE were faster and less laborious than Soxhlet extraction. The former three methods required less solvent than Soxhlet extraction. SFE required no concentration of the solvent extracts. SFE and ASE failed to perform simultaneous parallel extractions because of instrumental limitations.

• Bulletin of the Korean Chemical Society
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• 제18권8호
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• pp.814-818
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• 1997

The chemical waste treatment, APEG (alkali/polyethylene glycol) process has been shown to be effective for the dechlorination of PCBs in transformer oil. Considerable amount of PCBs, however, still remains in the waste exceeding the 25-50 ppm limit set by regulatory agency. A new thermal regeneration technology has been developed in our laboratory for disposal of hazardous organic wastes. Due to the limited oxidation of carbon surface through the reverse movement of flame front to oxidant flow, this technology was termed counterflow oxidative system (COS). Specially, the oxidant flow in the COS process is a principal parameter which determines the optimum conditions regarding acceptable removal and destruction efficiency of adsorbed organic wastes at minimal carbon loss. The COS process, under optimum conditions, was found to be very effective and the removal and destruction efficiency of 99.99% or better was obtained for residual PCBs in the waste while bulk (≥90%) of carbon was recovered. Any toxic formation of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo furans (PCDFs) were not detected in the regenerated carbon and impinger traps. The results of surface area measurement showed that the adsorptive property of regenerated carbon is mostly reclaimed during the COS process.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 1999년도 추계학술대회 논문집
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• pp.225-228
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• 1999

The formation of dioxin (term used here to refer to both polychlorinated dibenzo-p-dioxins, PCDDS, and dibenzofurans, PCBFs) in combustion processes is of concern because of the extreme toxicities of some of these compounds and because of their resistance to degradation in the environment. The number and location of chlorine substituents differentiate dioxin homologues and isomers, respectively. There are a total of 75 PCDD congeners and 135 PCDF congeners.(omitted)

• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2001년도 춘계심포지움 및 학술발표회
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• pp.137-137
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• 2001

It is it well known fact that the most relevant toxic emissions such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-1ike polychlorinated biphenyls (PCBs) are produced from incinerators. Induction of cytochrome P450IA1 catalyzed 7-ethoxyresorufin 0-deethylase (EROD) activity in mammalian cell culture (EROD-microbioassay) is a selective and sensitive parameter used for the quantification of dioxin-like compounds. (omitted)

• Bulletin of the Korean Chemical Society
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• 제23권6호
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• pp.817-824
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• 2002

Granular activated carbon(GAC) is highly effective in removing organic compounds which are resistant to biological disintegration in wastewater treatment. However, GAC has reached its full adsorptive capacity, GAC needs to be regenerated before it can be used for a further adsorption cycle. Countercurrent oxidative reaction (COR) technique has been developed and evaluated for the regeneration of spent GAC. Various parameters such as flame temperature, the loss of carbon, destruction and removal efficiency (DRE) of organic compounds, surface area, surface structure, adsorptive capacity, etc. were examined to determine the performance of COR. The results of these tests showed that adosorptive capacity of regenerated GAC was completely recovered, the loss of carbon was controllable, flame temperature was high enough to insure complete destruction and removal $(\geq99.9999%)$ of specific organics of interest, polychlorinated biphenyls (PCBs), that are thermally stable, and on formation of toxic byproducts such as polychlorinated dibenzo-p-dioxins (PCDDs) or polychlorinated dibenzofurans (PCDFs) were detected during the regeneration process. The COR technique is environmentally benign, easy to use and less copital intensive than other available regeneration technologies.

• Fisheries and Aquatic Sciences
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• 제10권2호
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• pp.93-101
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• 2007

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in marine sediments from Mokpo coastal water of Korea. Total and toxic equivalent (TEQ) concentrations of PCDD/Fs ranged from 19.4 to 175pg/g dry weight and ranged from 0.195 to 2.87 pg WHO-TEQ/g dry weight, respectively. These PCDD/F concentrations were below the safety sediment value (20 pg TEQ/g dry weight) of chronic toxicity. A highly significant correlation between the concentrations of PCDD/Fs and total organic carbon (TOC) in marine sediments was observed. Overall PCDD/F concentrations in the sediments were elevated in rivers and at inner locations close to harbors, indicating that these contaminants derived from local discharges of human activities. PCDD/F concentrations measured in our study were lower than those in several industrialized areas in Korea. Nonparametric multidimensional scaling (MDS) ordination showed that combustion processes from industrial complexes are the major source of PCDD/Fs in Mokpo coastal water.

• 분석과학
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• 제20권1호
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• pp.10-16
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• 2007

생활폐기물 열분해-가스화-용융공정 2개 시설(A 및 B 시설)에 대하여 PCDDs/PCDFs 농도를 조사한 결과, A시설은 2차연소로후단, 보일러후단, 굴뚝에서 PCDDs/PCDFs의 농도는 각각 0.88, 2.29, 0.16 ng I-TEQ/$m^3$으로 나타났다. B시설에서 열분해-가스화-용융로후단, 굴뚝에서 PCDDs/PCDFs 농도는 각각 0.22, 0.05 ng I-TEQ/$m^3$로 나타났다. 두 시설 모두에서 고온의 연소로보다 냉각구간의 보일러에서 다이옥신의 재합성으로 인하여 농도가 증가되었다. 또한 A시설에서는 2, 3, 4, 7, 8-PeCDF, 2, 3, 4, 6, 7, 8-HxCDF, 1, 2, 3, 6, 7, 8-HxCDF 순서로 높은 농도를 나타냈으며, B시설은 2, 3, 4, 7, 8-PeCDF, 1, 2, 3, 7, 8-PeCDD, 2, 3, 4, 6, 7, 8-HxCDF 순서로 높게 나타났다.

• Journal of Applied Biological Chemistry
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• 제55권4호
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• pp.253-261
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• 2012

PCDD/Fs 및 DL-PCBs는 농식품 잔류 유해물질 중 높은 생물독성 및 생물농축성으로 안전성 우려가 높아 많은 연구자들이 관심을 갖는 유해물질들이다. 하지만, 대부분의 오염조사연구는 지방함유량이 높은 육류 및 수산물을 중심으로 이루어지고 있어, 다소비 농산물인 곡류를 대상으로 한 다이옥신 잔류분석 연구결과가 부족하여 식이섭취를 통한 다이옥신류 노출평가를 수행하는데 어려움이 있다. 본 논문에서는 17종의 PCDD/Fs 및 14종의 DL-PCBs에 대하여 2010년산 쌀과 2011년산 보리에 대한 잔류 분석 및 이를 통한 한국인의 일일 섭취노출량을 조사하였다. 전국 8개 도에서 채취한 36점의 백미시료와 전남 및 전북에서 채취한 7점의 보리시료에 대한 잔류분석결과 백미 중 다이옥신류의 각 도별 평균 잔류량은 2.98-4.98 pg/g w.w.이었으며, 보리의 다이옥신류 평균 잔류량은 3.00-3.24 pg/g w.w.로 확인되었다. 쌀과 보리를 통한 국민 1인당 다이옥신 섭취노출량은 1.03 pg-TEQ/day/person와 0.0534 pg-TEQ/day/person 수준이었고, 이를 한국인 평균체중 55 kg을 기준으로 환산할 경우 Lower bound 시나리오의 경우 TDI대비 0.46와 0.03%였으며, Upper bound 시나리오의 경우 5.5와 0.18%로 국내산 쌀과 보리를 통한 다이옥신류 노출기여도는 미미한 것으로 판단된다.