• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.591-607
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• 2013

The objectives of the study were to evaluate the aquatic environment of an urban stream using various ecological parameters of biological biomarkers, physical habitat quality and chemical water quality and to develop a "Multimetric Eco-Model" ($M_m$-E Model) for the ecosystem evaluations. For the applications of the $M_m$-E model, three zones including the control zone ($C_Z$) of headwaters, transition zone ($T_Z$) of mid-stream and the impacted zone ($I_Z$) of downstream were designated and analyzed the seasonal variations of the model values. The biomarkers of DNA, based on the comet assay approach of single-cell gel electrophoresis (SCGE), were analyzed using the blood samples of Zacco platypus as a target species, and the parameters were used tail moment, tail DNA(%) and tail length (${\mu}m$) in the bioassay. The damages of DNA were evident in the impacted zone, but not in the control zone. The condition factor ($C_F$) as key indicators of the population evaluation indicator was analyzed along with the weight-length relation and individual abnormality. The four metrics of Qualitative Habitat Evaluation Index (QHEI) were added for the evaluations of physical habitat. In addition, the parameters of chemical water quality were used as eutrophic indicators of nitrogen (N) and phosphorus (P), chemical oxygen demand (COD) and conductivity. Overall, our results suggested that attributes of biomarkers and bioindicators in the impacted zone ($I_Z$) had sensitive response largely to the chemical stress (eutrophic indicators) and also partially to physical habitat quality, compared to the those in the control zone.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.318-318
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• 2011

자연수를 가압(4~5기압)하면서 물과 공기의 비를 4:1~3:1로 혼합하면 수체 내 초미세기포(Diameter $3{\sim}10{\mu}m$)가 발생하는데 이를 산소용해수라 하며 수질정화시설 또는 양식장 등에 널리 사용되고 있다. 산소용해수의 특징은 기포의 비표면적이 넓고 10시간 이상 포화 농도를 유지하여 수체에 잔류하는 시간이 길기 때문에, 일반 산기석을 활용한 포기나 순산소 용해 등의 타 방법과 구별된다. 산소용해수의 산소전달효율은 기존 방법과 큰 차이를 보이기 때문에 실제 적용시에는 대상수를 이용하여 산소전달계수($K_{L}a$)를 사전에 산정할 필요가 있다. 본 연구에서는 한국건설기술 연구원의 안동 수자원 환경실험센터 내 실외형 콘크리트 사각반응수조에 산소용해장치 및 확산장치를 결합한 일체형 시스템을 적용시켜 2010년 9월~2011년 1월의 5개월간 결과를 분석, 본 장치의 $K_{L}a$를 산정 후 수질정화의 활용 면에서 검토하였다. $K_{L}a$의 산정에는 다양한 방법이 이용되나 용존 산소 농도의 제어에 한계가 있는 실외 대형실험장에 적합한 Lewis and Whitman의 Two-film 이론에 근거한 정상포기법을 적용하였다. 체적 $80m^3$의 수조 내에서 현장 유지용수를 대상으로 실험한 결과 산소전달계수는 $0.324\pm0.050$/min, 포화농도는 8.64 mg $O_2$/L, 도달시간은 11 /min이 산정되었으며, 이는 기존 산기석 포기의 산소전달계수 범위인 $0.105\pm0.019$ /min보다 약 3.1배 높은 결과를 보였다. 또한, 확산장치의 수류 순환 방향 및 정도를 검토하기 위하여 실험수조에서 1m단위로 격자를 구성한 후 초음파 유속계로 실측한 결과 0.0~2.5 m/s 의 평면적 유속범위를 도출하였다. 그리고 전체 순환을 고려했을 때 용존산소는 약 8시간 후 8.64 mg $O_2$/L 값에 도달하여 안정화 되었으며, 강한 수류순환과 산소용해수에 의해 하상에 존재하는 퇴적물들의 이송 및 산화촉진을 유도하였다. 이를 근거로 실험수조의 체적과 기준 가동시간인 8시간을 적용시켰을 때, 실험구 수질은 대조구와 비교하여 COD, T-N, T-P가 모두 25~35% 개선되었다. 이 결과는 여과공정 없이 단순 순환만을 고려한 물리적 수질정화 방법의 단독 활용 가능성을 나타내며, 기존 연구에서 나타난 SOD (Sediment oxygen demand) 저감 능력을 감안할 때 향후 폐쇄성 수역의 수질관리에도 효율적으로 활용할 수 있음을 시사한다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.2
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• pp.106-117
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• 2006

We measured the concentrations of organic matter and metallic elements (Al, Fe, Cr, Mn, Ni, Cu, Zn, As, Cd, Pb and Hg) in the surface sediments of Masan Harbor (in the southern sea, Korea) to evaluate the geochemical characters of sediment and the pollutions by organic matter and metallic elements. The mean grain size of the surface sediments in the study area ranged from $5.6{\phi}$ to $7.8{\phi}$, indicating silt sediment. The water content of the surface sediments exceeded 60% except at some stations. The contents of ignition loss (IL), total organic carbon (TOC) and total nitrogen (TN) ranged from 7.2-14.3%, 1.2-3.2%, and 0.10-0.28%, respectively. Based on the C/N ratios, the organic matter in the surface sediments of Masan Harbor may originate from terrigenous sources including fluvial inputs (mainly sewage in urban areas). The chemical oxygen demand (COD) and acid volatile sulfide (AVS) ranged from $11.3-29.9\;mgO_2/g\;dry$ and 0.20-4.47 mgS/g dry, respectively, and low concentrations were observed near a shipping route. In addition, the concentrations of metallic elements showed large spatial variations in Masan Harbor and the distributions of metallic elements were also comparable to those of organic matter. This implies that the distributions of organic matter and metallic elements in the surface sediments of Masan Harbor are mainly controlled by biogenic matter and artificial action (mainly dredging). In addition, we calculated the enrichment facto. (EF) and geoaccumulation index (Igeo) in order to evaluate pollution by metallic elements. The enrichment of metallic elements relative to Al was three to eighteen times higher at the study sites, compared to levels in the Earth's crust except for Fe, Ni and Mn. In addition, the Igeo class indicated that the surface sediments in the study area were moderately to strongly polluted in terms of metallic elements.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.10
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• pp.992-998
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• 2008

Recently, a new concept for nitrogen removal that is simultaneous nitrification and denitrification(SND) has been studied for wastewater treatment process. The DMR(Daiho Microbic Revolution) process that used in this study consists of two suspended anoxic, anaerobic reactors and an aerobic biofilm reactor. The function of aerobic environment and the intensity of air flow rate(2.0, 1.0, 0.5, 0.4, 0.2 L/min) were studied in the biofilm reactor; also SND and nutrient removal efficiencies were investigated. Experimental results indicated that the change in air flow did not affect COD$_{Cr}$ removal significantly. Thus sustained at 93%. The lower the air flow rate, the higher T-N removal efficiency was attained(i.e.80% at 0.2 L/min). SND efficiency was 62, 65, 72 and 78% corresponding to each air flow rate. T-P removal was sensitive to aeration intensity and removal enhanced from 75% to 96% when the air flow rate was changed from 2.0 to 0.5 L/m; however second release occured in the clarifier at 0.2 L/min. Phosphorus content of activated sludge was 5.0%, as P releases and acetate uptake a ratio of 0.75 mg P/ mg HAc.

• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.396-403
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• 2017

The purpose of this study was to investigate water quality for irrigation water used in Napa cabbage cultivation. The water samples were analyzed for physiochemical and microbiological quality for a total of 111 samples including surface water (n = 75) and groundwater (n = 36) collected from five different regions where Napa cabbage is massively grown. As a conclusion, the levels of fecal indicators for surface water were higher than those for groundwater. The numbers of coliform from surface water and groundwater were 1.96-4.96 and 0-3.98 log MPN/100 mL, respectively. Enterococci were detected in 95% (72/75) of surface water samples and 22% (8/36) of groundwater samples. Besides, 97% (73/75) of surface water samples were observed being contaminated with Escherichia coli, and 22% (8/36) of groundwater sample was positive for E. coli. In the case of surface water, E. coli and coliform correlate to T-P, and enterococci showed relevance to the suspended solid (SS) and biochemical oxygen demand (BOD). In groundwater, fecal indicator bacteria showed relevance to the SS and chemical oxygen demand (COD). These results could be provided as fundamental date for establishing microbial standard of water used in leafy vegetables cultivation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.1 s.28
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• pp.21-28
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• 2007

The purpose of this study was to observe the effect on the water quality and sediment environment by the use of Nano-S for anti-Red tide material. The experiment was performed at subtidal and intertidal zone during six months(from Aug 2005 to Feb. 2006). The experiment sites were divided with concentration of materials. One is lower concentration(0.1%) and the other is higher concentration(1%). The results of experiments didn't show the remarkable influence of the materials effect before and after applying the Nano-S and the red mud. pH, salinity and DO were slowly increased during experiment period but nutrients were conversely decreased in the seawater. In the subtidal zone, qualities of sediments, IL, AVS and COD, were gradually lowered and the similar results were appeared in the intertidal zone. These results showed similar trends over all the experiment sites including control site. The results of heavy metals also did not show the interest different effect before and after applying the Nano-S and red mud compared with control site.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.622-630
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• 1998

Rotating Biological Contactor (RBC) was tested for the removal of total ammonia nitrogen (TAN) by using simulated aquaculture system. RBC performance was evaluated by controlling revolution rate of disk and hydraulic residence tile (HRT). The optimum revolution rate of disk was 4 rpm, As HRT of RBC was increased, TAN removal efficiency of RBC and TAN concentration of rearing water were increased. HRT for maintaining lowest TAN concentration of rearing water was 9.5 minutes and at that condition TAN concentration of rearing tank was $1.03 g/m^3$

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.1
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• pp.67-73
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• 2014

This study was performed to determine the anticancer effects of cultivated Orostachys japonicus (COJ) and wild Orostachys japonicus (WOJ) on primary human prostate cancer cells (RC-58T/h/SA#4 cells). The morphology of cells treated with COJ and WOJ was distorted to shrunken cell masses. In addition, cell death induced by COJ and WOJ was associated with increased population of cells in sub-G1 phase as well as the formation of apoptotic bodies and nuclear condensation. COD and WOJ markedly reduced the number of viable prostate cancer cells in a dose-dependent manner, and cell numbers were lower than control cells. COJ and WOJ also inhibited increases in cell proliferation induced by environmental hormones such as dioxin and bisphenol A in charcoal-treated FBS (cFBS) medium. COJ and WOJ methanol extracts at the tested concentrations (150, 300, and 600 ${\mu}g/mL$) also dose-dependently inhibited cell proliferation induced by environmental hormones. These results indicate that COJ and WOJ exert anticancer effects on primary human prostate cancer cells.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.1
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• pp.49-54
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• 2003

This study was conducted to evaluate characteristics of particle composition and organic matter distribution for tidal flat sediments in the Saemankeum area. The tidal flat sediments consist of predominantly sand and a little of silt, whereas the content of clay was very low. The analyzed values of particles of tidal flat sediments were in the range of $4.60\~10.90\;{\phi}$ for mean size and $-0.1\~1.75\;{\phi}$ for sorting and $-1.0\~0.92\;{\phi}$ for skewness and $0.27\~6.75\;{\phi}$ for kurtosis. The tidal flat sediments are interpreted as representing significant effect of the environmental change due to the construction of Saemankeum embankment. The ORP was in the range of -133$\~$200 (mean 73) mV. But 24 stations of the total stations showed reduction condition, The concentration of CODs was in the range of 17.54$\~$6,176.3 mg/kg. The ratio of C/S was 0.02$\~$0.45 (mean 0.24). And the Saemankeum tidal flat sediment was a little effected by input organic pollutants from upper site area. Conclusively, conservation of the Saemankeum tidal flat sediment was requested because it is for the growing fishery and low organic matter.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.3 s.26
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• pp.171-177
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• 2006

To illustrate the characteristics of marine environment in coastal waters of stationary fisheries, field observations were carried out in August and November, 2001. Water temperatures in Jindong Bay compared with those in Masan Bay were about $2.0^{\circ}C$ higher in August and about $0.7^{\circ}C$ in November. Salinities were lowest in the western part of Jindong Bay. It was found that salinity increased gradually from the western part of Jindong Bay to Masan Bay. Sea water in Masan Bay can be characterised as lower temperature and higher salinity, compared with those in Jindong Bay. Concentrations of suspended solids in the inner parts of Jindong Bay were higher than 15mg/L in August. Suspended solids in both regions of Jindong Bay and Masan Bay showed contrastive distributions, especially in November. That is, higher concentrations of suspended solids were found in the inner parts of Jindong Bay and off Masan Bay. Concentration of chemical oxygen demand in Masan Bay was highest, 7mg/L.