• Journal of Korean Society for Atmospheric Environment
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• v.19 no.2
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• pp.205-216
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• 2003

We have gathered exposure data on ambient air quality level and investigated dose-response slope factors of air pollutants such as fine particle, HAPs (metals, VOCs, PAHs) and dioxins in Seoul. Theoretical mortality incidences were estimated from exposure to these pollutants. From the results, priorities were ranked in the order fine particle, metals, VOCs, dioxins and PAHs by ordinal scale, and the uncertainties relative to those risk estimates were described.

• Bulletin of the Korean Chemical Society
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• v.17 no.4
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• pp.334-338
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• 1996

Tetra-chlorodibenzo-p-dioxins (tetra-CDDs) were prepared by microscale pyrolysis of trichlorophenates. During the pyrolysis reaction, tri-, di-, and mono-CDDs were also formed by the thermolysis of tetra-CDDs. The dechlorination pathways of tetra-CDDs were suggested for this reaction. The identification of these products was performed with capillary column gas chromatography-mass spectrometry.

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.792-796
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• 2003

Polychlorinated dibenzo-p-dioxins (PCDDs) are extremely toxic and persistent environmental pollutants. Their chemical reactivities and other physicochemical/biological properties show a strong dependence on the chlorination pattern. With increasing the number of chlorines, dioxin congeners become more electronegative and gain higher electron affinities. The vertical electron affinities (VEA) are related with the LUMO energies of neutral molecules. LUMO energies of all PCDD congeners were calculated at the B3LYP/6-31G** level and those of some selected congeners at the level of B3LYP/6-311G**//B3LYP/6-31G** and B3LYP/cc-pvtz/ /B3LYP/6-31G**. The total energies of neutral and anionic species for dibenzo-p-dioxins (DD), 1469-TCDD, 2378-TCDD, and OCDD were calculated at the level of B3LYP/6-31G**, B3LYP/aug-cc-pvdz, and B3LYP/ aug-cc-pvtz//B3LYP/6-31G**. By using the four congeners with D2h symmetry as reference molecules, we could estimate VEA (B3LYP/aug-cc-pvdz) of 75 PCDD congeners based on the linear correlations between LUMO energy and VEA (B3LYP/6-31G**) and between VEA (B3LYP/6-31G**) and VEA (B3LYP/aug-ccpvtz// B3LYP/6-31G**). Results show that all PCDDs with the number of Cl ≥ 3 have positive electron affinities. The PCDD electron affinity values provided in this work can be a useful data set in understanding the congener-specific reactivities of dioxins in various environmental media.

• The Korean Journal of Community Living Science
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• v.23 no.2
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• pp.129-136
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• 2012

Dioxins are chemical substances that are not properly decomposed degradation under natural photochemical, biological and chemical conditions in the environment, and bio-accumulate through the food chain, so pose a risk of causing adverse effects to human health and the environment. Ninety seven percent of human exposure to dioxins comes through meat, fish, dairy consumption and so on. Pork is the largest proportion meat aspect of daily intake in the Korean food. Pigs are three times more than Cattle in terms of breeding population and production amount in the world, and the amount is increasing every year. Therefore, it is necessary to monitor the exposure level of dioxins in pig's body. Also, it is required to evaluate the presence of these chemical substances in the pig's feed grain such as corn, soybeans, and tallow. The purpose of this study was to evaluate PCDD/Fs in pig's feed to search the origin of PCDD/Fs. Feed samples obtained were wheat from East Europe, corn from South America and America, soybean meal from Korea, America, South America and India and tallow from Korea. The preparation of samples was based on the EPA method 1613. Instrumental analysis was based on the use of high resolution gas chromatography coupled to high resolution mass spectrometry (HRGC/HRMS). The concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PCDD), which are the most toxic potent dioxins, were not observed in any of the samples. However OCDD was detected in most of the samples. The TEQs in the feed samples were ranged from 0 pg TEQ/g to 0.09841 pg TEQ/g. Especially, the high level of TEQs was observed in the samples of wheat from East Europe and soybean meal from Korea.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.E
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• pp.13-21
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• 1995

This Pilot study identifies potential dioxin and furan sources and medical plastic wastes produced from hospital solid waste streams. In this study, air emissions of dioxins and furans from sources in the U.S., which were estimated by the U.S. Environmental Protection Agency (EPA), were summarized. Potential loading routes of dioxins and furans to the U.S.-Canada Great Lakes region have also been identified in trcent surveys. In addition, medical and hospital solid wastes produced in typical large city hospitals were characterized as important potential sources of dioxins and furans. Plastic contents in medical Plastics Characterization Survey (MMPCS), plastics composition data were obtained from a survey of five Massachusetts Hospitals and Medical Centers. By identifying plastic wastes as a percentage of total hospital wastes, we were able to use data from a preliminary study that analyzed the waste stream of 16 major New York City hospitals (NYCMWS) characterizing the plastic content of the wasters. This study determined the types of plastic wastes included in each medical waste stream (regulated medical waste or non regulated medical waste) and it discussed the potential for recyclibility of hospital plastic wastes. The combination of the NYCMWS and the MMPCS surveys provides for the first overview of the size of the recycling task of hospital plastic wastes and the potential of dioxin elimination if dioxin generating plastics were to be eliminated from hospital use.

• Environmental Analysis Health and Toxicology
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• v.17 no.4
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• pp.285-298
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• 2002

In Korea, no CRA (comparative risk analysis) studies have been undertaken, nor have their methodologies of such studies been established. Therefore, the objectives of this study were to establish the framework of CRA consisting of health risk, economic risk and perceived risk, and to estimate and compare these risks among the three environmental problems of air pollution, indoor air pollution and drinking water contamination, which are themselves subject to the eight sub -problems of hazardous air pollutants (HAPs), regulated pollutants (representative as PM 10) and dioxins (PCDDs/PCDFs) in air pollution, indoor air pollutants (IAPs) and radon in indoor air pollution, and drinking water pollutants (DWPs), disinfection by -products (DBPs) and radionuclides in drinking water contamination in Seoul, Korea. After which, the priorities of these problems were set by individual and integrated risk. From the results, the rankings of both health risk and economical risk were in the following order: radon, PM10, IAPs, HAPs, DWPs, dioxins, DBPs, and radionuclides among the eight sub problems. On the contrary, the ranking of perceived risk was in the following order: HAPs, dioxins, radionuclides, PM10, DWPs, IAPs, Radon and then DBPs among the eight sub-problems.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.659-663
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• 2001

In Japan, the municipal solid waste, which amounts to 50 million tons, is generated every year and most of it is incinerated. The bottom and fly ashes are disposed to the registered disposal areas under the provisions of The Waste Disposal and Public Cleaning Law. Especially, as the fly ash from the municipal waste incineration (the primary fly ash) contains heavy metals (lead, zinc, etc) and dioxins, it cannot be disposed directly without decontamination, such as moiling, cementation, chelating and dissolving processes provided in the law. However, these procedures for decontamination, except melting, are not enough for dioxins. Even in case of melting, the fly ash from the process (the secondary fly ash) contains high concentration of heavy metals (e.g., Zn; 1-20%, Pb; 1-10%). For these reasons, Metal Mining Agency of Japan (MMAJ), a governmental organization, started a four-year project to develop the treatment technologies of these fly ashes in 1999. The purpose of the project is to establish the integrated technologies to recover the valuable metals from, and to decontaminate, the primary and secondary fly-ashes in the practical scale by utilizing the existing metallurgical processes and facilities, along with the energy saving and the reduction of the environmental impact.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.547-552
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• 2007

This study examined the thermal reactions of 2,4-dibromophenol (diBP), 2,6-diBP and 2,4,6-triBP. The products obtained under pyrolytic conditions were analyzed by gas chromatography/mass spectrometry (GC/MS). 2,7-dibromodibenzo-p-dioxin (diBDD) was the major compound produced from the thermal reaction of 2,4-diBP. In addition, monoBDD and triBDDs were obtained through a process of debromination and bromination, respectively. The pyrolysis of 2,6-diBP and 2,4,6-triBP produced two major brominated dioxin isomers through direct condensation and a Smiles rearrangement. The two ortho-Brs in 2,6-diBP and 2,4,6-triBP mainly led to the production of dioxins, whereas in addition to 2,7-diBDD, 2,4-diBP produced two furans as minor products, 2,8-dibromodibenzofuran (diBDF) and 2,4,8-triBDF, through the intermediate dihydroxybiphenyl (DOHB). The maximum yield of the major dioxins was obtained at 400 oC, and decomposition by debromination at 500 oC resulted in less substituted bromodioxins.

• Analytical Science and Technology
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• v.23 no.6
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• pp.595-606
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• 2010

A total 221 samples of the retailed foods collected from 2004 to 2007 was examined to estimate the level of dioxins(29 congeners) by the isotopic dilution method, and the exposure of population of Korean to dietary of dioxins was performed. Dioxins levels were calculated using TEF values established in 1998 and 2005, respectively. The average levels (pg TEQ/g) were less than 0.01 for polished rice, 0.04 (poultry)-0.13 (beef) for meats, 0.04 (milk)-0.05(cheese) for milk and dairy products, 0.13 for egg (york, only) and 0.11 (alaska pollack)-1.35 (pacific mackerel) for fishes. The estimated daily intake of Korean through foods was 0.47 pg TEQ/kg bw/day, and it was estimated as about 11% to tolerable daily intake (TDI; 4 pg TEQ/kg bw/day) of Korea and Japan. Consequently, it was concluded that there was no health risk.

• Applied Chemistry for Engineering
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• v.4 no.4
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• pp.662-671
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• 1993