• Proceedings of the Korea Water Resources Association Conference
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• 1991.07a
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• pp.76-87
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• 1991

• Water for future
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• v.46 no.5
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• pp.76-83
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• 2013

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.597-602
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• 2004

Field experimental study was performed to examine characteristics of nutrient export from paddy rice fields with irrigation practices. Experimental fields with surface-water and ground-water irrigation were monitored and analyzed during rice culture period. The water balance showed that outflow generally balanced the inflow showing that about half (58~68%) of total outflow was lost by surface drainage. Water and nutrient export are more in surface-water irrigation paddy than in ground-water irrigation paddy. The reasons might be more irrigation water available and easy to use in surface-water irrigation. If irrigation water reduced, it could result in reduction of nutrient export in paddy rice fields, which can save water and protect water quality. However, deviation from conventional standard practices might affect the rice yield and further investigations are necessary.

• Journal of information and communication convergence engineering
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• v.4 no.2
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• pp.92-96
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• 2006

Hardware for monitoring the water quality using water fleas is developed. Water flea is a frequently used biological sensor for monitoring the water quality. Water fleas quickly respond to the incoming toxic water by changing their activity when they are exposed. By measuring the activity of water fleas, the incoming toxic water is instantly detected. So far the measurement of activity of water fleas has been done with a system equipped with both a light source of LED and a light detector of photo transistor. Water flea itself is, however, sensitive to light resulting in incorrect response and the system has two inconvenient separate parts of the light source and the detector. This paper suggests a system using a CCD camera instead of a light source and a detector. The suggested system processes the image data from the CCD camera in real time without any delay. The developed system becomes a part of the remote water monitoring embedded system.

• Journal of the Korean earth science society
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• v.22 no.1
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• pp.47-64
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• 2001

Water mass classification was conducted using the data of 1985 and 1986 in the East China Sea and the Korea Strait. Kuroshio water (type K) and mixed water (type I) were broadly distributed at 50 m depth in winter and spring, and mixed waters (type I to IV) were distributed in summer and autumn. At 100 m depth of the East China Sea, and mixed water (type I) was broadly distributed in winter and spring, and mixed waters (type I to III) were in summer, and type I was in autumn. Water mass in summer is the most influenced from the Chinese coastal water. In the Korea Strait, the Kuroshio water (type K) was the main water mass in winter and spring, and mixed waters (type I to IV) were in summer and autumn. If temperatures are corrected to remove the cooling effect from the atmosphere, the Kuroshiowater region was diminished, however the mixed water region was expanded in winter and spring. This shows that although the Kuroshio water appears to be a main water mass of the East China Sea and the Korea Strait in winter andspring, in reality the mixed water (type I) which is slightly changed from the Kuroshio water (type K) widely distributed. The tongue-shaped distribution of low density surface water indicates that the water mixed with the Chinese coastal water flows to the Korea Strait and the Okinawa in summer.

• Journal of Soil and Groundwater Environment
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• v.15 no.6
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• pp.99-106
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• 2010

We investigated springs in Seoul in 2009 to know the change of water quality according to storage method of spring water, the concentration of chemical compounds and their correlation. Even spring water that originally satisfied national standard for drinking water could be exceeded national standard for drinking water by storage method such as storage bottle, temperature and period; especially used PET bottles could affect the increase of total colony counts. Therefore, spring water is desirable to be consumed on the spot, or to be stored in sterilized bottles in refrigerator rather than room temperature at home, and also to be consumed shortly not exceeding 24 hours. Total colony counts, coliform, yersinia, $F^-$, $Cl^-$, $NO_3^--N$, hardness, total Solids, pH, color and Al were exceeded national standard for drinking water at some springs. The result of correlation analysis shows that hardness and total solids, which are caused by several ionic compounds, had relatively high correlations with other chemical compounds.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.7
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• pp.371-376
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• 2016

In this study, the survey of bisphenol-A in indoor water service pipes rehabilitated with epoxy resin was conducted and the risk assessment was done to investigate the effect on the human health to drink tap water. Bisphenol-A in raw water was detected in a range of 50~118 ng/L in all samples, where the limit of quantification was 10 ng/L. This is caused by inflow of the sewage effluent or the tributaries of the surrounding area containing bisphenol-A. Bisphenol-A was not detected in finished water after the advanced water treatment process. It was achieved by its removal from the processes of flocculation-precipitation and oxidation of ozone and chlorine and by being changed to other by-product materials. For the indoor water service pipe, bisphenol-A was not detected in all cases which was not coated with epoxy resin. However, when epoxy resin is lined within the indoor water service pipe, bisphenol-A was identified at maximum level of 521 ng/L and was detected above the limit of quantitation at 68 percentages of all samples. The Hazard Quotient (HQ) at the maximum level (521 ng/L) of the detected bisphenol-A is 0.004, which is less than the reference value of 0.1 for the tap water intake. Therefore, it is considered that the detected levels of bisphenol-A in this study would be safe to drink tap water.

• Journal of Korean Society on Water Environment
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• v.32 no.5
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• pp.410-418
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• 2016

This study was conducted to improve the analysis method used for N-nitrosamines and to investigate the occurrences of N-nitrosamines in tributaries of the Han-river, intake stations, water treatment plants and tap water used within the city of Seoul. The samples were pretreated through a solid phase extraction and analyzed using a gas chromatography tandem mass spectrometer (GC-MS/MS). The GC-MS/MS in CI mode was compared with the GC-MS/MS in EI mode by the method detection limits (MDLs). MDLs by GC-CI/MS/MS and GC-EI/MS/MS were 0.2 ~ 1.1 ng/L and 0.2 ~ 1.4 ng/L, respectively. Samples were collected from ten tributaries of the Han-river (T1 ~ T10), six intake stations (I1 ~ I6), six water treatment plants (P1 ~ P6) and 25 taps in Seoul city. The maximum levels of N-nitrosodimethylamine (NDMA) were 0.013 μg/L, 0.008 μg/L, 0.006 μg/L and 0.002 μg/L in tributary water, raw water, finished water and tap water samples, respectively. Detected levels were much lower than 0.1 μg/L corresponding to the guideline value of WHO.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.6
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• pp.707-714
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• 2016

In order to prevent secondary pollution of tap water, corrosion characteristics are investigated, and corrosion index are calculated using LI and LR to manage corrosiveness. As targeted water treatment plants from 2014 (July, once) to 2015 (July and October, 2 times), 70 plants are selected by making a division for each area and water system. (treated water samples, n=240, raw water samples, n=72). In result of pH analysis, treated water was lower than raw water to 7.12, and 7.29, respectively. LI were investigated in the order of Seomjin river, Nakdong river, Han river, Geum river, to -2.08, -1.24, -1.11, -1.10 (at raw water), and -2.18, -1.59, -1.51, -1.35 (at treated water), respectively. In case of water quality goal value (LI = -1) in Japan as control of corrosiveness, management object was investigated about 83.3%.

• Journal of Korea Water Resources Association
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• v.56 no.5
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• pp.357-362
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• 2023

The conflict between upstream and downstream regions is a representative social conflict in Korea. It is important issues in the economic and environmental aspects related to interests of property rights and water quality conservation. however, it is insufficient for studies on the economic damage and benefits between upstream and downstream by policy. We studied validity for drinking water protect zone, one of the major water conflict in Korea, by comparison between social loss by property rights restriction in the upstream and social benefits in the downstream and we proposed integrated water management policy in basin level.