• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.466-473
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• 2020

A marine air drone is a new device that can be used to respond to and prevent marine casualties. Determining the districts where marine air drones can be deployed helps the government decision makers identify efficient policy. The aim of this study is to develop a model using the fuzzy-analytic hierarchy process (F-AHP) and additive ratio assessment (ARAS) method to evaluate appropriate districts for deploying marine air drones. To verify the applicability of the proposed model, a case study was performed with respect to the Korea coast guard (KCG) districts. Since the deployed marine air drones are characterized by a high degree of overlap between the evaluation attributes. the F-AHP is used to determine the weights of identified criteria. The results of this study, show that missing people from the shore was the most important criterion for deployment of the drone. For ranking the local districts of the KCG, the ARAS is applied in the case study with the single goal of 50% reduction in marine casualties. Consequently, the highest priority district was identified as Mokpo, followed by Incheon, Seogwipo, Taean, Wando, Yeosu, Pohang, Tongyeong, Gunsan, Bolyeong, Jeju, Buan, Donghae, Sokcho, Ulsan, Uljin, Busan, Changwon, and Pyeongtaeg.

• Applied Biological Chemistry
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• v.40 no.4
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• pp.342-346
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• 1997

Contents of heavy metals in paddy soils and brown rice of near the Kunsan industrial complex area were investigated. Average total heavy metal contents in paddy soils were Pb 34.33, Cd 0.50, Cu 35.49, and Zn 71.67 mg/kg respectively. There are no correlation between distances from industrial complex and contents of heavy metals in paddy soils. Average contents of heavy metals in brown rice grown above paddy soil were Pb 1.74, Cd 0.07, Cu 3.54, and Zn 16.53 mg/kg. Relationships between 0.1N HCl soluble heavy metals in paddy soils and contents of brown rice showed positive significant correlations for Pb at l% $level(r=0.6853^{**})$ and for Zn at 5% $level(r=0.5420^*)$. Relationships between total contents of heavy metals in paddy soils and contents of brown rice showed only positive significant correlation for Pb at 1% $level(r=0.7131^{**})$. Contents of heavy metals in paddy soils and brown rice of near the Kunsan industrial complex was polluted partly by the influence of smoke and dust out from industrial complex but not polluted anxious level

• Journal of Korean Society of Environmental Engineers
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• v.32 no.3
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• pp.248-255
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• 2010

This study was carried out to assess the feasibility of the electron beam irradiation as a mean of red tide control in coastal water. Prorocentrum minimum, Prorocentrum micans, Cochlodinium polykrikoides, Heterosigma akashiwo, Alexnadrium catenella were selected and cultured for experiments, and red tide occurring in Tongyeong(2007. 8. 15) was also tested under the same conditions. The irradiation dose were 1 kGy, 2 kGy, 4 kGy and 8 kGy. The result showed 50~65% extinction in red tide cells was observed right after irradiation dose of 1 kGy and 86~97% within 1 day after irradiation, compared with control. Chlorophyll-a concentration of red tide was reduced by 50~64% immediately and it was drastically reduced up to 86~97% 1 day after irradiation. When the culture was irradiated at 1 kGy, 28~47% of s-protein was released immediately, and 77~138% was released 1day after irradiation. 77~212% of s-carbohydrate was excreted after 1 day while 16~45% of s-carbohydrate was excreted immediately. A transmission electron microscope(TEM) observation for the irradiated red tide revealed that the cell was destroyed and intracellular biopolymeric substance was leached out from the damaged cell as a result of electron beam irradiation. These results imply that electron beam irradiation is enable to control red tide by flocculation with extracellular biopolymer. The paralytic shellfish poisoning(PSP) toxin contents produced by Alexandrium catenella was decreased 48% by 1 kGy of electron beam irradiation compared with the unirradiated cells. As a result, electron beam irradiation was effective for detoxication as well as destruction of red tide.

• Environmental Analysis Health and Toxicology
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• v.22 no.4
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• pp.321-327
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• 2007

4-nonylphenol (4-NP)이 해산어류인 조피볼락, Sebastes schlegeli의 혈장 vitellogenin (VTG), alkaline-labile protein phosphorus (ALPP), calcium(Ca), glutamate pyruvate transaminase (GPT) 및 hepatosomatic index (HSI)에 미치는 영향을 조사하였다. 실험어에 3일간격으로 $estradiol-17{\beta}$ ($E_2$, 5 mg/kg B.W.) 또는 4-NP(0, 10, 50, 100및 200 mg/kg B.W.)을 복강에 2번 주사한 후, 7일째에 채혈과 적출을 통해 혈장과 간장을 수집해 분석이 실시되었다. 대조 실험어에는 용매로 사용된 70% 에탄올만이 투여되었다. $E_2$ 투여 실험어의 혈장 단백질을 전기 영동상으로 분석한 결과 약 170 kDa의 위치에서 짙은 VTG 밴드가 관찰되었으나, 용매만 투여한 대조 실험어의 혈장에서는 동일 밴드가 관찰되지 않았다. 4-NP 투여한 모든 실험어의 혈장 단백질에서는 $E_2$ 투여 실험어와 동일한 VTG 밴드가 관찰되었다. 혈장 ALPP와 Ca 농도도 4-NP 투여 실험어에서 $E_2$ 투여 실험어와 유사하게 증가하였으며, 이들 농도 변화는 VTG 합성과 더불어 증가하는 경향을 나타냈다. 혈장 전위효소인 GPT와 HSI도 $E_2$ 투여 실험어와 유사하게 4-NP가 투여된 모든 실험어에서 급격히 증가하였다. 이상의 결과로부터 연안생태계 내에서 서식하는 어류가 4-NP과 같은 내분비 장애물질(Endocrine Disrupting compounds, EDCs)에 의해 영향을 받는지를 규명하기 위한 생물학적 지표로서 VTG와 더불어 혈장 ALPP와 Ca이 사용가능 할 것으로 판단된다. 또한, 조피볼락과 같은 해산어가 EDCs에 노출되어 VTG가 합성될 때 간장 기능의 손상으로 혈장 전위효소인 GPT가 일시적으로 종가하고 간장도 비대해져 HSI가 높아지는 것으로 판단된다.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.8
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• pp.798-807
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• 2008

Due to economic impairment derived from metal corrosion of pumping station installed around coastal area, it was needed for related cause-effect to be investigated for understanding practical corrosion behavior and providing proper control. This research was thus carried out to determine whether the microbe can influence on metal corrosion along with its control in the laboratory. For this study, groundwater was sampled from the underground pump station(i.e. I Gas Station) where corrosion was observed. Microbial diversity on the samples were then obtained by 16S rDNA methods. From this, microbial populations showing corrosion behaviors against metals were reported as Leptothrix sp.(Iron oxidizing) and Desulfovibrio sp.(Sulfur reducing) Iron oxidizing bacteria were dominantly participating in the corrosion of iron, while sulfate reducing bacteria were more preferably producing precipitate of iron. In case of galvanized steel and stainless steel, iron oxidizing bacteria not only enhanced the corrosion, but also generated its scale of precipitate. Sulfate reducing bacteria had zinc steel corroded greater extent than that of iron oxidizing bacteria. In the inactivation test, chlorine or UV exposure could efficiently control bacterial growth. However as the inactivation intensity being increased beyond a threshold level, corrosion rate was unlikely escalated due to augmented chemical effect. It is decided that microbial corrosion could be differently taken place depending upon type of microbes or materials, although they were highly correlated. It could be efficiently retarded by given disinfection practices.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.4
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• pp.159-163
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• 2004

This study was performed to estimate the water quality of pH, salinity, dissolved oxygen, ammonium and sulfur hydroxides of sediment in shrimp aquaculture farms of Southwestern coastal of Korea from June to September, 2003. We surveyed the status of water quality and achieved the improve water and sediment quality to restraint the production of ammonium and sulfur hydroxides from sediment of shrimp aquaculture farms. The concentrations of dissolved oxygen increased from noon to the evening for 6 hour and decreased to 2.98 ppm at six o'clock in the next morning and increased repeatedly, even though DO level has a different level in sunny day and cloudy day. This results suggest that the most importance time of the control of DO in shrimp aquaculture farm is next early morning and if the DO concentration increased continuously which may be growing up the concentrations of NH₄/sup +/ and H₂S. The measured of pH and salinity were suitable to growth of shrimp. However, the level of ammonium and sulfur hydroxides produced from the sediments of shrimp aquaculture farms were 2.30 ppm and 0.075 ppm, respectively, which are exceeded to the concentration of guide line for the growth of shrimp. In the results of this study, we found it difficult to improve the water quality using of the present frame of shrimp aquaculture farms. Then, we can improved water quality of DO, NH₄/sup +/ and sediment quality of ORP, H₂S and also achieved down to the rate of shrimp fatal by changed the frame of shrimp aquaculture farms in the scale of laboratory.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.3
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• pp.323-329
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• 1998

The data of Secchi disc observation collected during $1966\~1990$ were analyzed to investigate the seasonal variation of transparency in the southeastern Yellow Sea. The bimonthly distribution of mean transparency showed that the isolines of transparency were roughly parallel to the isobaths. The transparency was low (3 m in february and 8 m in August) if the shallow water less than 20 m depth in comparition to the higher values (10 m in february and 17 m in August) in the deeper water. The lowest transparency was found in winter. The transparency increased in spring and the highest transparency occurred in summer. The water becomes turbid in autumn. Suspended solid concentrations in winter are ranged from 28 to 130 $mg/{\ell}$, and from 8 to 60 $mg/{\ell}$ in summer. The seasonal variation of transparency seems to be mainly affected by resuspension of solid from the bottom. The amounts of suspended solid are large in winter due to the vertical convection by cooling effect and tubulence by the strong wind, and small in summer due to the strong stratification and weak wind.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.5
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• pp.399-405
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• 1992

Using $MnO_2-coated$ fiber extraction and gamma counting techniques, we measured the distributions of $^{226}Ra$\;and\;^{228}Ra$ in the surface waters at 14 stations of East Sea of Korea in September, 1988. The concentrations of $^{226}Ra$\;and\;^{228}Ra$ in the surface waters ranged $70-110\;dpm/10^3l$ and 102=232 $dpm/10^3l$, respectively. In general, the concentrations of Ra isotopes were shown higher in the coastal and southern stations than those in the outer and northern stations in our observed area. Also, the concentrations of Ra isotopes in the study area were significantly higher than values in the other area of the East Sea and Kuroshio surface water, but much lower than the concentrations in the surface water of Yellow Sea reported previously. There was an inverse relationship between the $^{226}Ra/^{228}Ra$ ratio and salinity in the surface waters of Kuroshio, Yellow Sea and East Sea of Korea. This indicates that the continental shelf waters such as Yellow Sea and East China Sea are main source of Ra isotopes in surface waters of the East Sea of Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.353-358
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• 1999

This study is to find out the effects of various iron concentrations on growth, feeding and feed efficiency of olive flounder, Paralichthys olivaceus, The growth rate, feeding rate and feed efficiency of olive flounder in each experiments were represented by the relative value. The relative growth rate and relative feed efficiency of olive flounder were kept almost constant below the iron concentration of 1.0 mg/$\ell$, but were significantly decreased above the 5,0 mg/$\ell$ iron concentration. The growth rate, feeding rate and feed efficiency of olive flounder exposed to 10.0mg/$\ell$ iron concentration were significantly decreased than that exposed to normal condition. From these results, it could be concluded that the high level of 5.0 mg/$\ell$ iron concentration in the bottom water would curtail production of olive flounder in coastal area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.359-367
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• 1999

For investigating the activities of algicidal bacteria, the variations of algicidal bacterial population and chlorophyll-a were checked weekly in Chindong Bay, Korea from May to July, 1998. For identifying their killing characteristics, three strains were selected from the isolated algicidal bacteria. The density of algicidal bacteria kept changing in the range of $6.0\times10^1$ to $6.4\times10^5$ cell $\ell^{-1}$. The density flux of algicidal bacteria coincided with that of chlorophyll-a by a week of lag time. Three algicidal bacteria isolated from field strains, H519S5-4, H605S5-15 and H605S5-22, were investigated in nine microalgal species, Heterosigma akashiwo, Chattonella sp. (Raphidlphyceae), Gymnodinium catenatum, Gyrodinium impudicum, Cochlodinium polyklikoides (Dinophyceae), Chaetoceros sp., Coscinodiscus granii, Ditylum brightwellii, Thalassiosira rotula (Bacillariophyceae). Strain H605S5-22 showed a wide algicidal activities over nine microlgae, strain H605S5-15 over H. akashiwo, G. catenatum, T. rotula, Chattonella sp. and strain H519S5-4 over H. akashiwo, Chattonella sp., Chaetoceros sp., G. catenatum. The activities of the three strains were detected by the secretion of algicidal substances. Therefore, it is suggested that the activities of algicidal bacteria have a significant influence over the population dynamics of phytoplankton and get involved with the sharp decrease in red tides in the coastal area.