• Journal of Korean Society on Water Environment
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• v.33 no.1
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• pp.15-33
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• 2017

Based on the existing pollutant emissin standards which are armed at the pollutant concentration of each pollution source, government formulated and implemented new management system of total water pollutant emission. By virtue of this new management system, pollution loading amount of individual watershed could be controlled, which achieved the requirement of water quality management such as TP and BOD. In initiate stage of it's implement, BOD was selected as object of water quality management, While it's necessary to consider the continuity of water quality data and established pollutant management laws and policy. During the ongoing management, TP management was added into the system while simply BOD management was not enough. However, the frequency of algae bloom in Han-river showed a trend of same, even though TP was treated as additional control target. Therefore, this paper will analyze different water quality parameters and characteristic of water quality, so that this study can be provide as reference for watershed management of water quality, by which the applicable management period and target pollutant can be selected in the future.

• Environmental Engineering Research
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• v.21 no.2
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• pp.211-218
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• 2016

Cheonggye-cheon is a partly restored urban stream located in central Seoul. We monitored fecal contamination using three different fecal indicators, total coliforms (TC), fecal coliforms (FC) and E. coli, to assess differences in each indicator on days of varying weather conditions. Presumptive TC, FC and E. coli colonies were identified by their 16S rRNA sequences. The results showed that enumeration of E. coli provided a better reflection of fecal contamination of the stream than TC and FC. The main sources of contamination were the inflow of fecal-polluted groundwater from the vicinity of a subway line and two inflowing streams. The fecal contamination was worsened on days with heavy rain because untreated sewage from a collecting facility flowed into the stream. Moreover, growth potential of fecal indicator (E. coli) in situ induced by algal exudates was measured. Our results suggest that an appropriate standard based on E. coli rather than TC and FC should be established for improving water quality management strategies of Cheonggye-cheon in the future.

• Korean Journal of Environmental Agriculture
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• v.19 no.5
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• pp.382-393
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• 2000

The principal indicators contributing to water qualities was screened by factor analyses, based on the monitored chemical parameters of water quality for various water resources from 1995 to 1999 in the small agricultural catchments of the Han River Basin. Water samples of streams, groundwaters, and reservoirs were taken four times a year from upper (Daegwanryong), middle (Dunnae and Chunchon) and lower (Guri) reaches of Han River Basin. In these areas, the respective type of farming practiced was alpine agriculture and livestocks raising, typical upland and paddy cultivation, and intensive cropping in the plastic film house. Water quality was monitored for twenty-one water quality parameters, including pH, EC, SS, T-N, T-P, COD, cations, anions, and heavy metals. pH, EC and COD of the stream waters were suitable for the Korea irrigation water quality guidelines. However, T-N and T-P concentrations of water samples in four catchments far exceeded the irrigation water guideline. Concentrations of canons and heavy metals in Wangsuk stream in Guri area were higher than those in streams in other areas. Factor analysis revealed that significant correlation was observed for 81 pairs out of 231 water quality indicators of stream water among the $21\;{\times}\;21$ cross correlation matrix of stream water quality indicators. The first factor accounted for 27.01% of the total variation in stream water quality indicators, and high positive factor loadings were shown on EC, K, Na, $NH_4\;^+-N$, $PO_4\;^{3-}$, $SO_4\;^{2-}$, and COD. Fifty-three water quality indicator pairs were significant out of 190 ground water quality parameters. The first factor accounted for 28.54% of the total variation in ground water quality indicators, and high loadings were revealed on EC, Ca, Mg, K, Na, $NH_4\;^+-N$, and $SO_4$. Twenty-nine pairs of reservoir water quality indicators were significant out of 66 pairs. The first factor accounted for 37.06% of the total variation in reservoir water quality indicators, and high loadings were shown on EC, Mg, K, Na, SS, T-P, Cl, and COD. These results demonstrate that EC was the first factor contributing to water quality.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.5
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• pp.551-557
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• 2015

The TMDL (Total Maximum Daily Load) has been used to determine the water quality target. LDC (Load Duration Curve) based on hydrology has been used to support water quality assessments and development of TMDL. Also FDC (Flow Duration Curve) analysis can be used as a general indicator of hydrologic condition. The LDC is developed by multiplying FDC with the numeric water quality target of the factor for the pollutant of concern. Therefore, this study was to create LDC using the stream flow data and numeric water quality target of BOD and T-P in order to evaluate the pollutant load characterization by flow conditions in Heukcheon stream. When it is to be a high-flows condition, BOD and T-P are necessary to manage. BOD and T-P did not satisfy the numeric water quality target for both seasons (spring and summer). In order to meet the numeric water quality target in Heukcheon stream, management of non point source pollutant is much more important than that of point source pollutant control.

• Journal of Korea Water Resources Association
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• v.57 no.1
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• pp.9-19
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• 2024

As using public monitoring data, analysing a trends of water quality change, establishing a criteria to determine abnormal status and constructing a regression model that can predict Chlorophyll-a, an indicator of eutrophication, was studied. Accordingly, the three freshwater lakes were selected, approximately 20 years of water quality monitoring data were analyzed for periodic changes in water quality each year using regression analysis, and a method for determining abnormalities was presented by the standard deviation at confidence level 95%. By calculating the temporal change rate of Chlorophyll-a from irregular observed data, analyzing correlations between the rate and other water quality items, and constructing regression models, a method to predict changes in Chlorophyll-a was presented. The results of this study are expected to contribute to freshwater lake water quality management as an approximate water quality prediction method using the statistical model.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.879-885
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• 2009

The present study was carried out to develop biological criteria for water quality assessment using benthic diatoms. Selecting of the indicator diatoms, three parameters were considered: broad distribution (180 taxa occurred over 3% at upper level), species abundance (158 taxa occurred over $1.5{\times}10^5cells/cm^2$), and sensitivity (184 taxa occurred more than once as 1st and 2nd dominant species). Overall, total 208 taxa were selected, including 38 varieties, 170 species, 34 genera, 9 families, 3 orders, and 1 phylum. The most dominant taxonomic group (family) was Naviculaceae (52%), followed by Diatomaceae (15%), Nitzschiaceae (12%) and Achnantaceae (11%). COD and TP were proposed as new water quality standards (draft) to improve the existing BOD standard and to manage and control efficiently non-biodegradable organic pollutants. With this regard, we used TP standard (draft) in developing biological water quality criteria for diatoms. TP standards (draft) proposed as Ia = 0.02 mg/L or less, Ib = 0.05 mg/L or less, II = 0.1 mg/L or less, III = 0.2 mg/L or less, IV = 0.4 mg/L or less, V = 0.6 mg/L or less and VI = above 0.6 mg/L. Biological assessment system (4 class system) was developed and proposed for diatom using modified Tropic Diatom Index (TDI). Biological assessment of TDI appear B grade (Good).

• Journal of Korean Society of Environmental Engineers
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• v.32 no.11
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• pp.1063-1068
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• 2010

This study compared UV and UV/$H_2O_2$ inactivation of E.coli, a possible indicator microorganism for fecal contamination of water, and $Q{\ss}$ phage, an indicator for pathogenic viruses. UV inactivation of $Q{\ss}$, T4 and lambda phages in actual secondary effluent was investigated, too. As a result, similar inactivation efficiency between $Q{\ss}$ phage and E.coli was observed during UV treatment, while $Q{\ss}$ phage showed higher resistance to UV/$H_2O_2$ than E.coli. $Q{\ss}$ phage resistance to UV or UV/$H_2O_2$ does not reflect those of all pathogenic viruses. However, the result tells that the use of E.coli inactivation efficiency in evaluating microbiological safety of water could not always ensure the sufficient safety from pathogenic viruses. Meanwhile, $Q{\ss}$ phage showed less resistance to UV than T4 and lambda phages, indicating that the use of $Q{\ss}$ phage as an indicator virus may bring insufficient disinfection effectiveness by causing the introduction of lower UV dose than required. Consequently, it can be thought that T4 or lambda phages would be more desirable indicators in ensuring the sufficient disinfection effectiveness for various pathogenic viruses.

• Journal of Korean Society on Water Environment
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• v.25 no.1
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• pp.76-83
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• 2009

In 2005, the 5.84-Km length of Cheonggyecheon stream, previously covered with concrete road, was uncovered in the middle of Seoul, Korea. We investigated microbial water quality in various sites in Cheonggyecheon stream. We took water samples on three different days. The sampling sites included inflow water from upper stream (Mojeongyo), midstream (Ogansugyo), and downstream (Muhakgyo). Fecal pollution indicator microorganisms were measured by both IDEXX $Colilert^{(R)}$ and $Enterolert^{(R)}$. Microbial community from these sampling sites was also characterized based on 16S rRNA gene sequences. The average concentrations of total coliform are 5 CFU/100 mL, 1474 CFU/100 mL, and 1776 CFU/100 mL at Mojeongyo, Ogansugyo, and Muhakgyo, respectively. The average concentrations of fecal coliform were 28 CFU/100 mL, 47 CFU/100 mL in Ogansugyo, and Muhakgyo, respectively. The concentrations of other fecal indicator microorganisms including E. coli and Enterococcus sp. increased in downstream. When we characterized the microbial community, unique microbial community were discovered at different sampling sites. This study suggests that Cheonggyechoen stream is likely affected by non-point fecal sources and has unique microbial environment as the river flows downstream.

• The Korean Journal of Malacology
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• v.13 no.2
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• pp.203-210
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• 1997

As a prioiminary study on usage of metabolic charateristics of the indicator species for indirect estimation of environmental water quality, effects of environmental pollutants on survival, filtration and oxygen consumption rates in Corbicula aeana were investigated at 17$^{\circ}C$ and $25^{\circ}C$ in 10 day afrer treatmint of pollutants. In case of glucose and complex fertilizer, the survival rates of the clams were 100% without any relation to individual sizes and water temperatures. In small sizes at $25^{\circ}C$, the survival rates of the clams by NH$_{4}$CI concentration were shown 95% at 10 mg/1 and 15mg/1, and 90% at 20mg/1, respectively. But the survival rate was 95%at 20 mg/1 of NH$_{4}$CI concentration in small size at 17$^{\circ}C$. The higher filtration and oxygin consumption rates were shown in small size at higher water timperatures(over $25^{\circ}C$), and generally filtration and oxygen consumption rates decreased with increase of glucose, complex fertilizer and NH$_{4}$CI concentrations, respectively. In general, effects of filtration and oxygen consumption rates at NH$_{4}$CI concentrations were shown slightly larger than those of glucose and complex fertilizer.

• Journal of Korean Society on Water Environment
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• v.27 no.6
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• pp.760-768
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• 2011

Jinwi Stream is considerably polluted. The urban development in a Jinwi Stream basin can make state of aquatic ecosystem worse. However, researches for aquatic ecosystems in Jinwi Stream are insufficient. In this study, biotic indices of periphytic diatoms (DAIpo and TDI), benthic macroinvertebrates (EPT, KSI and ESB) and fish (IBI) were compared with the annual water quality data. Benthic macroinvertebrates indices showed highly significant correlations with concentrations of organic materials and nutrients, while DAIpo, TDI and IBI showed low correlations with them. In particular, ESB can be considered as an useful indicator that reflects the degree of diversity and abundance of biotic community as well as water quality. In polluted and disturbed streams as Jinwi Stream, DAIpo, TDI and IBI appeared to be not available for evaluating and discriminating the water quality, although they have been known as good indices in general streams.