• 한국물환경학회지
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• 제35권2호
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• pp.152-164
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• 2019

In this study, a Benthic Macroinvertebrates Family Index (BMFI) was developed using 100 indicator groups (99 families including Chironomidae with 2 phena). Families were assigned a score between 1 and 10 depending on their sensitivity to organic pollution. The BMFI was composed of the sensitivity and relative abundance of the indicator taxa. Sensitivity values of each group were generally similar to Biological Monitoring Working Party (BMWP) scores or Walley, Hawkes, Paisley, Trigg (WHPT) scores of UK, Japanese BMWP scores, and the FBI tolerance values of North America. However, sensitivity values of some taxa were significantly different from those of foreign countries, which seemed to have resulted from discrepancy in species composition, difference of taxonomic classification system, or methodological difference for estimation of sensitivity. As an annual average level, BMFI showed significant correlation with concentration of 5-day biochemical oxygen demand (BOD5) (correlation coefficient r = -0.80, n = 569 sites), total suspended solids (r = -0.68), and total phosphorus (r = -0.79). In addition, BMFI revealed strong correlation with Shannon-Weaver's species diversity (r = 0.85), Margalef's species richness (r = 0.85) and McNaughton's dominance (r = -0.84). Correlation between BMFI and water quality parameters or community indices such as species diversity did not show significant difference compared to that of species-level indices such as BMI (Benthic Macroinvertebrates Index). This means that BMFI is a more useful indicator in terms of easy identification of organisms. BMFI was used to assess the environmental status of 3,017 sites of Stream Ecosystem Survey conducted by the Korean Ministry of Environment between 2016 and 2018. As a result, about half of all sites appeared to be in good condition, and a quarter in poor condition.

• 센서학회지
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• 제23권4호
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• pp.272-277
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• 2014

At present, the index of chemical oxygen demand (COD) is widely used as an indicator of organic water pollution with biochemical oxygen demand (BOD). But, traditional COD measurement method are not only with various chemical reagents exhausted, but also long time consumed, the operation procedure and the modification are much professional. This paper reported a novel COD measurement system using double-beam and multiple wavelength analysis UV-VIS spectrometries. It consists of pulsed xenon lamp, two-way optical fiber, optical switch, spectrometer and main processor. Proposed COD measurement system obtains any spectral information of water sample (KHP standard sample and two river water and wastewater) and reference sample (distilled water) in the range of 200~520 nm, corresponding to the COD concentration from 0 to 300 mg/L through calculating the UV absorbance. The system show improved precision and can work continuously fast at time interval about 25 seconds.

• 한국식품영양학회지
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• 제25권4호
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• pp.1016-1022
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• 2012

In order to investigate the effects of 70% EtOH extract obtained from Hovenia dulcis Thunberg on enzymes relating reactive oxygen intermediate, cancer-stricken animals induced by DEN (N,N-diethylnitrosamine) were recovered by administering the extract of Hovenia dulcis Thunberg. It showed that there was no effect on the generation of superoxide radical by the extract of Hovenia dulcis Thunberg. However, considering the increase of the activity of Cu, Zn-SOD and Mn-SOD in the tested animal class, the extract of Hovenia dulcis Thunberg could participate directly in removing of superoxides. The experimented-animals treated with the extract of Hovenia dulcis Thunberg showed an increase in the activity of the enzymes, catalase and glutathione peroxidase, which can eliminate hydrogen peroxide pertained in liver tissue. The extract of Hovenia dulcis Thunberg seemed to have some factors that accelerate the oxidation. Also, the extract of Hovenia dulcis Thunberg showed effects on the enzymes relating to the active oxygen toxicity which could be an indicator of aging and body toxicity.

• 한국환경과학회지
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• 제21권9호
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• pp.1115-1129
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• 2012

The objective of this study was to analyze long-term annual and seasonal trends of water chemistry on landuse patterns and seasonal precipitation using 72 sampling sites within Namhan River watershed during 2001-2010. Water quality, based on multi-parameters of water temperature(WT), dissolved oxygen(DO), biochemical oxygen demand(BOD), chemical oxygen demand(COD), suspended solids(SS), total nitrogen(TN), total phosphorus(TP), and electric conductivity(EC) varied largely depending on monsoon rain and landuse patterns such as forest, cropland, and residence. Concentrations of BOD and COD as an indicator for organic matter pollution, increased during summer monsoon season at the cropland and residential streams. Values of TN and TP were higher in residential streams than in the forest and cropland streams. In the meantime, DO values had weak relations to the landuse patterns of forest and cropland cover. Water quality was worst in cropland and residential streams, and also most degradated in 4th order streams. Overall, our results suggest that efficient water quality management is required in the cropland and residential landuse streams.

• KSBB Journal
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• 제5권3호
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• pp.307-313
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• 1990

배양기와 16비트 마이크로컴퓨터를 접속하여 호기성 미생물의 고농도 유가배양시스템을 구성하였다. 기질공급을 위한 제어변수로는 용존산소(DO)를 이용하였다. 용존산소측정기의 출력신호를 컴퓨터에 입력시켜 측정한 DO값에 근거하여 교반모터의 교반속도와 산소유량을 제어함으로써 배양액의 DO를 일정하게 유지하였으며, 연동펌프의 제어에 의해 기질공급을 안정하게 수행하였다. 기질공급의 제어와 DO의 제어를 한가지의 하아드웨어 및 소프트 웨어로 수행할 수 있었다. 제어시스템을 이용하여 메탄올이용균인 Methylobacillus sp. SKI을 유가배양한 결과 배양액의 DO제어와 메탄올 공급의 제어가 무리없이 수행되었으며, 배양 10시간만에 16.53g/l의 균체농도에 도달하였다.

• 한국환경과학회지
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• 제28권7호
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• pp.629-637
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• 2019

The purpose of this study was to evaluate the effect of high-salinity wastewater on the microbial activity of Aerobic Granule Sludge (AGS). Laboratory-scale experiments were performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen removal efficiency, sludge precipitability, and microbial activity were evaluated under various salinity injection. The COD removal efficiency was found to decrease gradually to 3.0% salinity injection, and it tended to recover slightly from 4.0%. The specific nitrification rate was 0.043 - 0.139 mg $NH_4{^+}-N/mg$ $MLVSS{\cdot}day$. The specific denitrification rate was 0.069 - 0.108 mg $NO_3{^-}-N/mg$ $MLVSS{\cdot}day$. The sludge volume index ($SVI_{30}$) ultimately decreased to 46 mL/g. The specific oxygen uptake rate decreased from an initial value 120.3 to a final value 70.7 mg $O_2/g$ $MLVSS{\cdot}hr$. Therefore, salinity injection affects the activity of AGS, causing degradation of the COD and nitrogen removal efficiency. It can be used as an indicator to objectively determine the effect of salinity on microbial activity.

• ALGAE
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• 제37권4호
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• pp.301-316
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• 2022

The red alga Compsopogon caeruleus can generally be found in tropical and subtropical waters worldwide. In addition to its natural habitats, this species may be found in waters that receive abnormally hot water, e.g., from powerhouses. To date, the presence of C. caeruleus has not been observed in thermally polluted lacustrine ecosystems in Poland, which has a moderate climate. The thalli of this red alga were found growing on Vallisneria spiralis in Lichenskie Lake. Importantly, this paper presents a previously unknown relationship between the temperature (20, 25, 30, 35, and 40℃) and oxygen requirements of C. caeruleus (based on ex situ measurements of O₂ consumption by thalli). Surprisingly, 35℃ can be the optimum temperature for C. caeruleus, and this temperature is higher than the values reported by some previous thermal analyses by approximately 10℃. Additionally, we reviewed and mapped the distribution of this nonnative and mesophilic red alga in natural / seminatural water ecosystems in Europe. Finally, we propose that the occurrence of C. caeruleus mature thalli can be a novel, simple and easy-to-recognize bioindicator of artificially and permanently heated waters in moderate climate zones by a regular discharge of postindustrial water.

• 한국환경과학회지
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• 제22권12호
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• pp.1561-1569
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• 2013

This study carried out a laboratory scale plasma reactor about the characteristics of chemically oxidative species (${\cdot}OH$, $H_2O_2$ and $O_3$) produced in dielectric barrier discharge plasma. It was studied the influence of various parameters such as gas type, $1^{st}$ voltage, oxygen flow rate, electric conductivity and pH of solution for the generation of the oxidant. $H_2O_2$ and $O_3$.) $H_2O_2$ and $O_3$ was measured by direct assay using absorption spectrophotometry. OH radical was measured indirectly by measuring the degradation of the RNO (N-Dimethyl-4-nitrosoaniline, indicator of the generation of OH radical). The experimental results showed that the effect of influent gases on RNO degradation was ranked in the following order: oxygen > air >> argon. The optimum $1^{st}$ voltage for RNO degradation were 90 V. As the increased of $1^{st}$ voltage, generated $H_2O_2$ and $O_3$ concentration were increased. The intensity of the UV light emitted from oxygen-plasma discharge was lower than that of the sun light. The generated hydrogen peroxide concentration and ozone concentration was not high. Therefore it is suggested that the main mechanism of oxidation of the oxygen-plasma process is OH radical. The conductivity of the solution did not affected the generation of oxidative species. The higher pH, the lower $H_2O_2$ and $O_3$ generation were observed. However, RNO degradation was not varied with the change of the solution pH.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3307-3311
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• 2013

A new fiber optical sensor was developed for the determination of 2,4-dichlorophenol (DCP). The sensor was based on DCP oxidation by oxygen with the catalysis of iron(III) tetrasulfophthalocyanine (Fe(III)PcTs). The optical oxygen sensing film with $Ru(bpy)_3Cl_2$ as the fluorescence indicator was used to determine the consumption of oxygen in solution. A lock-in amplifier was used for detecting the lifetime of the oxygen sensing film by measuring the phase delay change of the sensor head. The different variables affecting the sensor performance were evaluated and optimized. Under the optimal conditions (i.e. pH 6.0, $25^{\circ}C$, Fe(III)PcTs concentration of 0.62 mg/mL), the linear detection range and response time of the sensor are $1.0{\times}10^{-6}-9.0{\times}10^{-6}$ mol/L and 250 s, respectively. The sensor displays high selectivity, good repeatability and stability, and can be used as an effective tool in analyzing DCP concentration in practical samples.

• 한국수정란이식학회지
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• 제24권3호
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• pp.231-235
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• 2009

Oxygen consumption has been regarded as a useful indicator for assessment of mammalian embryo quality. However, there was no standard criterion to measure the oxygen consumption of embryos. Here, we measured oxygen consumption of bovine embryos at various developmental stages was measured using a scanning electrochemical microscopy (SECM). We found that the oxygen consumption significantly increased in blastocyst-stage embryos compared to other stage embryos (from 2-cell-stage to morula-stage), indicating that oxygen consumption reflects the cell number ($5.2{\sim}7.6{\times}10^{14}/mol\;s^{-1}$ versus $1.2{\sim}2.4{\times}10^{14}/mol\;s^{-1}$, p<0.05). In the morula-stage embryos, the oxygen consumption of in vivo derived embryos was significantly higher than that of in vitro produced embryos ($4.0{\times}10^{14}/mol\;s^{-1}$ versus $2.4{\times}10^{14}/mol\;s^{-1}$, p<0.05). However, there was no significant difference in consumption of oxygen by in vivo and in vitro-derived bovine blastocyst-stage embryos (p>0.05). In the frozen-thawed blastocyst-stage embryos, live embryos showed significantly higher oxygen consumption than dead embryos ($4.7{\times}10^{14}/mol\;s^{-1}$ versus $1.0{\times}10^{14}/mol\;s^{-1}$, p<0.05). These results indicate that the measuring oxygen consumption by SECM can be used to evaluate bovine embryo quality.