• 한국환경과학회지
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• 제11권9호
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• pp.961-969
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• 2002

This study was performed : 1) to establish the experimental analysis conditions for the sorption and desorption of toxic organic contaminants to/from the activated sludge, sediment, and clay, and 2) to determine the sorption and desorption equilibrium coefficients of some representative halogenated aliphatic compounds. Through the preliminary sorption test using Azo dye, a setting of quantitative experimental conditions to determine the sorption and desorption characteristics was decided as follows; equilibration time of 180 minutes, centrifuge for 15 minutes at 5000$\times$g, and 500mg/$\ell$ of TOC concentration. The sorption and desorption characteristics of halogenated aliphatic compounds onto activated sludge, sediment and clay could be described very well using the Freundlich isotherm. The preference of the average sorption capacity of the overall compounds showed in the sequence sediment 0.26mg/g, clay 0.23mg/g, and activated sludge 0.11 mg/g. The desorption rate of the sorbed compounds onto activated sludge, sediment and clay was approximately 89.8%, 35.3%, and 66.4%, respectively.

• 한국환경과학회지
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• 제11권7호
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• pp.737-742
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• 2002

Sorption and desorption is an important phenomenon to determine the fate of halogenated aliphatic hydrocarbons in the aqueous phase. This study was conducted to develope a predictive equation capable of estimating the sorption and desorption potentials of halogenated aliphatic hydrocarbons onto the sludge from activated process, sediment, and clay. It has shown that the sorption and desorption parameters can be accurately estimated using Quantitative Structural Activity Relationship(QSAR) models based on molecular connectivity indexes of test compounds. The QSAR model could be applied to predict the sorption and desorption capacity of the other halogenated aliphatic hydrocarbons. The QSAR modeling would provide a useful tool to predict the sorption and desorption capacity without time-consuming experiments.

• Asian-Australasian Journal of Animal Sciences
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• 제17권9호
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• pp.1255-1259
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• 2004

The objective of this study was to evaluate the effects of halogenated compounds, organic acids, unsaturated fatty acids and their mixtures on in vitro methane production and fermentative characteristics of mixed rumen microorganisms. Agents used in two in vitro experiments were bromoethanesulfonic acid (BES) and pyromellitic diimide (PMDI) as halogenated compound, fumarate and malate as organic acid, and linoleic acid and linolenic acid as unsaturated fatty acid sources. Ruminal fluid collected from a Holstein steer fed tall fescue and concentrate mixtures was incubated at $39^{\circ}C$ for 48 h with addition of those materials. Single supplementation of halogenated compounds, organic acids or unsaturated fatty acids decreased in vitro methane production (p<0.05). The second experiment was designed to investigate effects of combination of one of halogenated compounds and either organic acids or fatty acids on methane production. Lower concentration of methane and lower A:P ratio were observed with PMDI compared with BES (p<0.01). In general medium pH, VFA, total gas and hydrogen production, and dry matter degradability were affected by addition of the same compounds. In addition, PMDI+malate treatment resulted in the highest molar proportion of propionate, and lowest A:P ratio and methane production (p<0.01). Hydrogen production was highest in PMDI+linolenic acid and lowest in BES+malate treatment (p<0.01). PMDI+malate combination was the most recommendable in reducing methane production without too much influence on digestibility under conditions of present studies.

• 한국화재소방학회논문지
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• 제17권4호
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• pp.7-12
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• 2003

연소열은 인화성 물질의 화재$.$폭발 위험성을 결정하는 주요한 물성치이다. 할로겐화 유기화합물의 순연소열을 예측하기 위해서, 원자기여법에 기반을 둔 경험식들이 개발되어 왔다. 본 연구에 개발된 경험식을 Cardozo와 Hanley의 경험식들과 비교해 보았다. A.A.D.를 보면 알 수 있듯이 본 연구에서 제안된 경험식으로 계산된 값이 실험값에 가장 근접해 있음을 확인하였다. 따라서, 본 연구에서 제안된 경험식은 여타 할로겐화 유기화합물의 연소열을 예측하는데 도움을 줄 것으로 사료된다.

• Archives of Pharmacal Research
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• 제8권1호
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• pp.21-30
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• 1985

Examination of the constituents of a marine sponge, Aplysina fishtularis, indicated that brominated tyrosine metabolites were mainly responsible for antimicrobial and antineoplastic activities. Halogenated tyrosine metabolites, 2, 6-dibromo-(2), 2-bromo-3-chloro-(3) and 2, 6-dibromo-(5), 5-a mino-2-bromo-6-chloro-(6) and 5-amino-2, 6-dich-loro-(7) 4-hydroxy-2-cyclohexenone-4-acetic acid lactams were identified as the major antineoplastic and antimicrobial principles. Many other brominated tyrosine metabolites were also confirmed, but they did not show antimicrobial and antineoplastic activities.

• Archives of Pharmacal Research
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• 제15권2호
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• pp.109-114
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• 1992

For the risk assessment of human exposure to volatile halogenated hydrocarbons, a dynamic purge trap/on-column cryofocusing method using capillary gas chromatograph-$^{63}Ni$ electron capture detector and thermal desorption unit was applied to analyze the free forms, metabolites of 1, 1, 2-trichloroethylene and 1, 1, 2, 2-tetrachloroethylene. The urine sample was diluted with distilled water, hydrolyzed and sealed. Then the inert gas was infused to purge out free 1, 1, 2-trichloroethylene, free 1, 1, 2, 2-tetrachloroethylene and urichloroethanol. These compounds were trapped to $Tenax^R$ / GC-gas trap device throughout clean up tube. Being undertectable to gas chromatograph directly, trichloroacetic acid was methyl esterificated and trapped in the manner above mentioned. The optimal incubation time to get best recovery of methyl ester was 4 hours at $60^circ$C. The concentrations of free volatile halogenated hydrocarbons and their metabolites in urine were obtained of free volatile halogenated hydrocarbons and their metabolites in urine were obtained from 5 healthy volunteers. This analytical method is expected to make the biological monitoring more precise and convenient.

• Journal of Microbiology
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• 제44권1호
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• pp.23-28
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• 2006

We investigated the effects of halogenated aromatic compounds (HACs) including naturally occurring ones (L-thyroxine, 3-chloro-L-tyrosine, 5-chloroindole, 2-chlorophenol, 4-chlorophenol and chlorobenzene) on polychlorinated biphenyl (PCB) dechlorination in sediment cultures. A PCB-dechlorinating enrichment culture of sediment microorganisms from the St. Lawrence River was used as an initial inoculum. When the culture was inoculated into Aroclor 1248 sediments amended with each of the six HACs, the extent of dechlorination was not enhanced by amendment with HACs. The dechlorination patterns in the HAC-amended sediments were nearly identical to that of the HAC-free sediments except the 3-chloro-L-tyrosine-amended ones where no dechlorination activity was observed. When these sediment cultures were transferred into fresh sediments with the same HACs, the dechlorination specificities remained the same as those of the initial inoculations. Thus, in the present study, the substrate range of the highly selected enrichment culture could not be broadened by the HACs. It appears that HACs affect PCB dechlorination mainly through population selection rather than enzyme induction of single population.

• 한국지하수토양환경학회지:지하수토양환경
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• 제6권3호
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• pp.73-91
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• 2001

미국지질조사소 NAWQA 프로그램에서 선정한 기준에 따라, 도시지역에서 채취한 도로를 흐르는 빗물과 일부 지하수의 휘발성유기화합물의 오염을 평가하기 위해 62개 휘발성유기화합물을 선택하였다. 62개 휘발성유기화합물은 3종류의 aromatic hydrocarbons, 13 종류의 alkyl benzenes, 1개의 ether, 26종류의 halogenated alkanes, 10종류의 halogenated alkenes 및 9종류의 halogenated aromatics를 포함하고 있다. 서울시 지역의 도로를 흐르는 빗물과 지하수의 휘발성유기화합물의 함량은 2000년 3월, 6월 및 11월에 시료를 채취하여 분석하였다. 모두 78개 시료(44개 도로를 흐르는 빗물시료, 27개 지하수 시료, 7개 하수종말처리장의 시료)가 채취되었으며, purge and trap 방법으로 추출하여 GC-MS로 분석하였다. 그 결과, alkyl benzenes과 aromatic hydrocarbons이 서울지역에서 자동차 통행에 의해 가장 영향을 받는 유기화합물이다. 분석된 62개 휘발성 유기화합물 중, 도로에 흐르는 빗물에서 검출되지 않은 휘발성유기화합물 성분은 단지 11개 성분뿐이었으나, 채취된 지하수에서 검출된 휘발성유기화합물은 14개 성분만이 검출되었다. 도로를 흐르는 빗물에서의 톨루엔 함량은 시료 채취 장소에 따라 변화가 매우 심하고, 0.1-29,310ppb이다. 벤젠의 함량은 0.05-33.0ppb, ethylbenzene은 0.05-960ppb, trichloromethane(chloroform)은 0.08-20ppb, trichloroethylene(TCE)는 0.03-4.30ppb, 1,1,2 trichloroethane은 0.1-50.0ppb이다. 채취된 일부 지하수 시료에 대한 예비조사 결과, dichloromethane(methylene chloride), trichloromethane(chloroform)와 toluene 등이 가장 자주 검출되는 성분이었다. 대부분의 aromatic hydrocarbons, alkyl benzenes및 다른 유기용매 성분은 검출농도 이하이다.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 1998년도 가을 학술발표회 프로그램
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• pp.153-156
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• 1998

• Environmental Engineering Research
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• 제18권3호
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• pp.169-176
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• 2013

The present study was designed to examine the concentrations, emission rates, and source characteristics of a variety of volatile organic compounds (VOCs) in 30 newly-constructed apartment buildings by measuring indoor and outdoor VOC concentrations over a 2-year period. For comparison, seven villa-type houses were also surveyed for indoor and outdoor VOC concentrations over a 3-month period. Indoor and outdoor air samples were collected on Tenax-TA adsorbent and analyzed using a gas chromatograph (GC)/mass spectrometer system or a GC/flame ionization detector system coupled to a thermal desorption system. The long-term change in indoor VOC concentrations depended on the type of VOCs. Generally, aromatic (except for naphthalene), aliphatic, and terpene compounds exhibited a gradual deceasing trend over the 2-year follow-up period. However, the indoor concentrations of the six halogenated VOCs did not significantly vary with time changes. Similar to these halogenated VOCs, the indoor naphthalene concentrations did not vary significantly with time changes over the 2-year period. Unlike the halogenated VOCs, the indoor naphthalene concentrations were much higher than the outdoor concentrations. The indoor concentrations of aliphatic and aromatic compounds were higher for the villa-type houses when compared to those of apartment buildings. In addition, four source groups (floor coverings and interior painting, household products, wood paneling and furniture, moth repellents) and three source groups (floor coverings and interior painting, household products, and moth repellents) were considered as potential VOC sources inside apartment buildings for the first- and second-year post-occupancy stages, respectively.