• Korean Journal of Environment and Ecology
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• v.18 no.3
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• pp.340-345
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• 2004

The embryotoxic effects of PCB (Aroclor 1248) on a Korean frog, Rana dybowskii was deter-mined by using the FETAX (Frog Embryo Teratogenesis Assay-Xenopus) protocol. The rates of mortality and malformed larvae were investigated by probit analysis. The results showed that PCB is highly embryolethal. From LC$_{50}$ of 1.48ppb and from EC$_{50}$ of 0.25ppb and TI of 5.7 were derived, which indicates PCB is to be considered a teratogenic compound. Specific malformations occurred in 62.0% as edema at the 0.1ppb, in 32.0% as tail deformations at the 1ppb, and in 68.0% as profound deformations at the 5ppb of PCB concentration which living embryos were exposed to. PCB suppressed the growth of head-tail length at a relatively low concentration (1.0ppb), and therefore growth inhibition as assessed by embryo length can be used as a sensitive indicator to evaluate the toxicity of pollutants in the environment. In conclusion, PCB must be considered highly embryotoxic to Rana dybowskii.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 1996.12a
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• pp.75-75
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• 1996

최근 가장 관심이 집중되고 있는 음용수중의 미량오염물질로는 인위적으로 첨가되는 소독제(disi octant)로 인한 소독부산물(disinfection by-products: DBPs)을 들 수 있다. 1970년대부터 염소소독시 수중의 유기오염물길과 반응하여 발암성물질 과 돌연변이 물질이 다수 함유되어 있는 클로로포름(chloform)을 포함한 트리할로메탄(Trih리omethane: THMs)의 생성이 발견되었으며 이로 인한 건강상의 영향이 지속적으로 보고되고 있다. 염소소독시 780가지 이상의 화합물이 염소와 휴믹산(humic acids)과의 반응에 의해 생성되며, 이중 대부분이 할로겐 화합물로 알려져 있다. 염소 소독부산물로는 인체발암력을 지니고 있는 트리할로메탄(THMs) 이외에도 할로아세틱산(Haloaceticacids: HAAs), 할로아세토나이트릴(Haloacetbnitriles: HANs)등이 주 생성물질인 것으로 알려져 있으나 우러나라의 원수특성에 따른 소독부산물의 생성능 (Formation potential)에 대한 연구가 미흡한 실정이다. 본 연구에서는 우리나라 주요 4대강(한강, 대청호, 영산강, 낙동강)의 원수를 실험실내에서 염소처리하여 생성되는 소독부산물의 생성농과 pH, 체류시간 등의 조건에 따라 생성능을 조사하였다. 각 화합물은 추출 및 농축과정을 거친 후 GC/MSD를 사용하여 물질을 확인한 후 할로겐화합물에 민감한 GC/ECD를 사용하여 시료를 분석하였다. pH와 시간, 원수중의 유기물 함량이 소독부산물의 생성에 많은 영향을 미치는 것으로 나타났다. THMs은 알칼리에서, HAAs의 경우는 약산성에서 접촉시간이 증가할수록 높은 생성능을 보였고, HANs의 경우는 급속히 생성했다가 시간이 경과함에 따라 소멸하며 약산성에서 높은 생성능을 보임을 알 수 있었다, 강별로는 낙동강에서 THMs파 HANs의 생성능이 비교적 높았고, 영산강에서는 HAAs의 생성능이 높았다. 각 원수의 특성에 따른 생성능을 파악함으로써 생성능 저감방안을 마련하며, 소독 부산물질의 인체노출평가에 따른 위해성평가를 통해 관리기준을 설정해야 할 것이다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.704-711
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• 2015

In this study, we have conducted a survey of AHP technique through the ocean experts to derive new items and revise assessment items and indices for risk of sunken ships based on the survey results. As a result of the survey, two new items such as accident cause and tidal current are derived. And it shows that existing items such as toxic liquid substance, remaining oil and explosive gas which were evaluated as one group are desirable to be evaluated respectively. Accordingly, we analyze the indices of the new eleven assessment items adjusted from the existing seven assessment items. As a result, the indices are ordered by toxic liquid substance, possibility of leaking, explosive gas, carrying capacity of fuel oil, sensitivity of sea environment, marine traffic environment, cause of accident, tidal current, keel clearance, ship type, and ship size. Especially, as compared with the indices of existing assessment items, the indices of sensitivity of sea environment and possibility of leaking are higher and the index of keel clearance is lower.

• Korean Journal of Environment and Ecology
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• v.33 no.2
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• pp.178-186
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• 2019

This study used the probit analysis to evaluate the toxicity of three chemicals - benomyl (Germicide), carbofuran (insecticide), and thiobencarb (herbicide) - with the FETAX (Frog Embryo Teratogenesis Assay-Xenopus) protocol using the incubated embryos of tree frog, Hyla japonica. The results showed that the larval body length decreased while the mortality and malformation rates increased as the concentrations of benomyl, carbofuran, and thiobencarb increased. The teratogenic concentration ($EC_{50}$) of benomyl, carbofuran, and thiobencarb were 1.00, 0.58, 4.75 mg/L, respectively, indicating that the malformation of larvae was the most sensitive to carbofuran. The embryo lethal concentration ($LC_{50}$) was 7.04, 28.71, and 16.12mg/L, respectively, indicating that benomyl showed the lowest embryo lethal concentration. The teratogenic index (TI) was 7.04 in Benomyl, 49.50 in Carbofuran, and 3.39 in Thiobencarb, indicating that the TI values were above 1.5, which is the criterion of teratogenicity, for all three chemicals. All three pesticides examined by this study were considered to be the most teratogenic substances, and the carbofuran was the most potent teratogen.

• Membrane Journal
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• v.31 no.5
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• pp.327-332
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• 2021

The use of membranes for MBRWG (Membrane Bioreactor for Waste Gas) treatment can provide highly selective separation of a waste gas stream followed by effective biological removal. MBRWG have several potential advantages, among which the most distinctive one is separation of gas and liquid phases at each side of membrane potentially allowing the optimal biomass control toward effective biodegradation of target gases as well as biofilm activation. This advantage becomes especially favorable for removal of hydrophobic toxic gases, such as xylene, by MBRWG systems, because the mass transfer, the toxicity, and thereby the biodegradation of hydrophobic gas treatment requires sensitive handling of liquid stream and water control near biofilm. Among various membranes for MBRWG treatment, PDMS-hollow fiber membranes provide the high gas mass transfer. Despite lower specific surface areas, capillary type membranes are also applied current MBRWG studies. In addition to the main application of membranes as biofilm supporter in MBRWG systems, there can be another application of membranes in a posterior process for removal of residual gases or dusts emitted from conventional biological waste gas treatment processes.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.2
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• pp.160-167
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• 1992

The growth of weeds and some other plants has been considered to be inhibited by sicklepod(Cassia tora L.) sharing the habitat. The study was conducted, for the first time, to propose that this phenomenon is not only due to competition for physical and nutritional conditions but also due to allelopathy. In addition, autotoxicity of sicklepod was examined. The results are summarized as follows. 1. Rice sheath length reduced progressively from 18 % to 36 % with increasing the concentration of treating aqueous extracts of sickle pod seeds, but rice germination was not affected. In contrast, radish hypocotyl length was not reduced by the aqueous extract treatment but radish germination was significantly reduced by 66 % at 1 : 10 and 1 : 5 treatment. 2. Total chlorophyll contents in rice seedling decreased from 50 % to 65 % by treatment of seed aqueous extracts diluted from 1 : 50 to 1 : 5 ratio. 3. Aqueous extracts of sicklepod leaves significantly reduced hypocotyl length and fresh weight in radish and germination in rice, but mung bean was slightly affected by aqueous extracts only in fresh weight. 4. Volatiles from fresh, immature seeds with husk reduced the radish germination and seedling growth and radish root growth appeared to be more sensitive to the exposure to volatiles from fresh immature seeds than both germination and hypocotyl growth. 5. Volatiles from sickepod leaves inhibited germination and growth of radish, rice and mung bean, and seedling growth was more sensitive to volatiles from leaves than germination. 6. Volatiles from sicklepod leaves reduced germination and radicle length of sicklepod itself. 7. Collectively, it is concluded that there are water-soluble and volatile substances responsible for allelopathy in sicklepod.

• Fire Science and Engineering
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• v.31 no.2
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• pp.52-60
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• 2017

Numerical simulations were performed to evaluate the habitability of an operator for a cabinet fire in the main control room of a nuclear power plant presented in NUREG-1934. To this end, a Fire Dynamics Simulator (FDS), as a representative fire model, was used. As the criteria for determining the habitability of operator, toxic products, such as CO, were also considered, as well as radiative heat flux, upper layer temperature, smoke layer height, and optical density of smoke. As a result, the probabilities of exceeding the criteria for habitability were evaluated through the sensitivity analysis of the major input parameters and the uncertainty analysis of fire model for various fire scenarios, based on V&V (Verification and Validation). Sensitivity analyses of the maximum heat release rate, CO and soot yields, showed that the habitable time and the limit criterion, which determined the habitability, could be changed. The present methodology will be a realistic alternative to enhancing the reliability for a habitability evaluation in the main control room using uncertain information of cabinet fires.

• The Korean Journal of Nuclear Medicine
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• v.38 no.5
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• pp.338-343
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• 2004

Purpose: The purpose of this study was to develop a small animal PET using dual layer phoswich detector to minimize parallax error that degrades spatial resolution at the outer part of field-of-view (FOV). Materials and Methods: A simulation tool GATE (Geant4 Application for Tomographic Emission) was used to derive optimal parameters of small PET, and PET was developed employing the parameters. Lutetium Oxyorthosilicate (LSO) and Lutetium-Yttrium Aluminate-Perovskite(LuYAP) was used to construct dual layer phoswitch crystal. $8{\times}8$ arrays of LSO and LuYAP pixels, $2mm{\times}2mm{\times}8mm$ in size, were coupled to a 64-channel position sensitive photomultiplier tube. The system consisted of 16 detector modules arranged to one ring configuration (ring inner diameter 10 cm, FOV of 8 cm). The data from phoswich detector modules were fed into an ADC board in the data acquisition and preprocessing PC via sockets, decoder block, FPGA board, and bus board. These were linked to the master PC that stored the events data on hard disk. Results: In a preliminary test of the system, reconstructed images were obtained by using a pair of detectors and sensitivity and spatial resolution were measured. Spatial resolution was 2.3 mm FWHM and sensitivity was 10.9 $cps/{\mu}Ci$ at the center of FOV. Conclusion: The radioactivity distribution patterns were accurately represented in sinograms and images obtained by PET with a pair of detectors. These preliminary results indicate that it is promising to develop a high performance small animal PET.

• Korean Journal of Environment and Ecology
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• v.26 no.5
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• pp.675-681
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• 2012

In this experiment, I investigated toxicity evaluation of chemicals using domestic frog embryos, along FETAX (Frog Embryo Teratogenesis Assay-Xenopus) protocol. I investigated $Cu^{2+}$ and Tebuconazole effect on the tree frog, Hyla japonica, embryos by probit analysis. Mortality and malformation rates increased and larval body length decreased depending on the concentrations of $Cu^{2+}$ and Tebuconazole. The teratogenic concentration ($EC_{50}$) of $Cu^{2+}$ and Tebuconazole were 0.05, 5.0mg/${\ell}$, respectively and the embryo lethal concentration ($LC_{50}$) of $Cu^{2+}$ and Tebuconazole were 0.16, 38.5, respectively. The teratogenic index (TI) appeared 3.0 in $Cu^{2+}$ and 7.7 in Tebuconazole, which showed teratogenicity in embryonic development of Hyla japonica. These results reveal that $Cu^{2+}$ and Tebuconazole in this experiment suppressed the development of embryos at relatively low concentration. Much of Hyla japonica embryos can be secured, and easy to incubate. In addition, mortality, malformation ratios, malformation patterns and growth rates are similar to the results from the other assay systems. Therefore, the Hyla japonica embryo teratogenesis assay system could be a useful tool to evaluate toxicity of pollutants in environment.

• Korean Journal of Environmental Biology
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• v.30 no.3
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• pp.231-237
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• 2012

Toxicity of $Ni^{2+}$ and Tebuconazole were investigated via FETAX (Frog Embryo Teratogenesis Assay-Xenopus) protocol using domestic frog embryos. Embryos of Black-spotted pond frog, Rana nigromaculata, were incubated and toxic effects of $Ni^{2+}$ and Tebuconazole were investigated by probit analysis. As a result, mortality and malformation rates were increased and larval body length was decreased in a dose dependant manner of $Ni^{2+}$ and Tebuconazole. The half maximal effective concentration ($EC_{50}$) of $Ni^{2+}$ and Tebuconazole were 0.07, $12.7mg\;L^{-1}$, respectively and the half maximal lethal concentration ($LC_{50}$) of $Ni^{2+}$ and Tebuconazole were 4.2, 39.1, respectively. The teratogenic index (TI) were 61.4 in $Ni^{2+}$ and 3.1 in Tebuconazole, respectively. These results reveals that $Ni^{2+}$ and Tebuconazole suppress the development of Black-spotted pond frog embryos at the low concentration as showing teratogenic effects in other assay system. Therefore, teratogen assay system using the Rana nigromaculata embryos could be useful as a tool to evaluate the toxicity of the pollutants in environment.