• Journal of Korean society of Dental Hygiene
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• v.12 no.5
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• pp.999-1006
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• 2012

Objectives : The purpose of this study was to understand and compare the knowledge of the adolescents and adults among the residents of Seoul metropolitan city about water fluoridation program. Methods : A total of 613 adolescents and adults between the age of 15 and 31-49 was surveyed by the questionnaire. Among them, the source of drinking water, the source of cooking water, awareness of caries prevention effect of water fluoridation program, awareness of cost benefit of health insurance of water fluoridation program, approval of water fluoridation program, awareness of health safety of water fluoridation program were surveyed. Results : 85.5% of adolescents and 88.9% of adults were surveyed to use public water supply for drinking water, and 95.3% of adolescents and 96.8% of adults were surveyed to use public water supply for cooking water. But only 14.0% of adolescents, comparing to the 42.1% of adults, were surveyed to be aware of the caries prevention effect of water fluoridation, and only 6.0% of adolescents, comparing to the 24.6% of adults, were surveyed to be aware of the caries prevention effect of water fluoridation to reduce to health insurance expenditure. About 82.6% of adolescents, comparing to the 92.1% of adults, were surveyed to vote for the fluoridation program, and only 6.8% of adolescents, comparing to the 28.6% of adults, were surveyed to be aware of health safety of water fluoridation program. Conclusions : Extensive oral health education program to the adolescents are necessary about using water fluoridation to prevent the dental caries.

• Journal of Environmental Science International
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• v.26 no.3
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• pp.345-362
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• 2017

The primary purpose of this study was to determine the risk of various disease outcomes due to exposure to cyanobacteria toxin (microcystin-LR) through drinking water in a Korean watershed. In order to determine the risk in a more quantitative way, the risk assessment framework developed by the National Research Council (NRC) of the United States (US) - hazard identification, dose-response relationship, exposure assessment, and risk characterization - was used in this study. For dose-response relationships, a computer software (BenchMark Dose Software (BMDS)) developed by the US Environmental Protection Agency (EPA) was used to fit the data from previous studies showing the relationship between the concentration of microcystin-LR and various disease outcomes into various dose-response models. For exposure assessment, the concentrations of microcystin-LR in the source water and finished water in a Korean watershed obtained from a recent study conducted by the Ministry of Environment of Korea were used. Finally, the risk of various disease outcomes due to exposure to cyanobacteria toxin (microcystin-LR) through drinking water was characterized by Monte-Carlo simulation using Crystall Ball program (Oracle Inc.) for adults and children. The results of this study suggest that the risk of disease due to microcystin-LR toxin through drinking water is very low and it appears that current water treatment practice should be able to protect the public from the harmful effects of cyanobacteria toxin (microcystin-LR) through drinking water.

• Journal of Environmental Impact Assessment
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• v.25 no.5
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• pp.357-368
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• 2016

Cambodia is the representative of developing country in Southeast Asia region. As a view point of water resource, Cambodia has in abundance but public sanitation problems persist in rural areas due to unsafe drinking water and untreated human waste. The purpose of this research is to prepare and develop new strategies for the water aid program in Cambodia by assessing, reviewing, and analyzing the present situation of water pollution for rural areas and the existing water use cycle in these regions. Pproyap and Langthle regions in Pursat province are selected as research areas. Cambodian's rural population in research areas relies on surface water stored in drinking-detention swamps, rain-water jars, and unprotected wells. The two types of main measures, thermotolerant coliform(TTC) bacteria and general pollutants, were conducted to assess the quality of selected water samples for research areas. TTC is a bacterial indicator of waterborne fecal contamination. For the 26 water samples, only one of the samples met the WHO standard for safe drinking water of 0 TTC colony forming units/100 mL.

• Journal of Environmental Health Sciences
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• v.10 no.1
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• pp.21-31
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• 1984

The purpose of this study was to find out more effective schemes on safe water supply in rural area. Then, this study was carried out to investigate drinking water qualities of 20 simple piped water supply systems and 20 water pumps in Chun Sung County, Kang Won Province from 12th December to 24th December, 1983 and was compared this results with the previous results that had been carried out at the same sample sites from 1st July to 30th August, 1981. 1. This results of water quality in winter are better than the previous results in summer because this results are identified as safe 20%, unsafe 35% in simple piped water supply systems, safe 50%, unsafe 20% in water pumps and the previous results are identified as safe 1.8%, unsafe 78.6% in simple piped water supply systems, safe 5.5%, unsafe 73.6% in water pumps. 2. Water qualities of water pumps are better than that of simple piped water supply systems because the former is identified as safe 50%, unsafe 20% and the latter is identified as safe 20%, unsafe 35%. 3. Drinking waters that are in need of chlorination in winter as well as summer are 45% of simple piped water supply systems and 30% of water pumps.

• Journal of Korean Society on Water Environment
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• v.24 no.2
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• pp.164-168
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• 2008

Perchlorate, which is still unregulated, is found in tap water, posing a threat to public health. In and out of Korea, there is no clear standard for drinking water quality or discharge. To make matters worse, Perchlorate study is in its infancy in Korea. This research tracked fresh water and purified water of water purification facility A and B located at the city of D, where Nak-dong River is being utilized as the purified water. And it was found that purified water shows no particular pattern in Perchlorate concentrations but represented a higher level of concentration compared to fresh water. With utilizing the research results, the study sought the impact of activated-carbon treatment process on Perchlorate elimination and found out that Perchlorate concentrations increased 38% after the process. The result proves that conventional water purification process can't eliminate Perchlorate. Therefore, it is reasonable that Perchlorate discharge from sources should be minimized.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.233-242
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• 2020

As studies and developments of nano-material increase, the release of the nano-sized material to water environment increase. Especially, silver nanoparticles have been found as dissolved and particulate state since nano-silver particle have been intensively used in industrial and our living environment due to the anti-bacterial effect of the nano-particles. The silver nano-particles and silver ion gives adverse effect on ecology and US-EPA set a secondary drinking water standards as 0.1 mg/L. Current study focused on the analysis of silver in groundwater, small scale water supply systems in Gyeongbook area. The results have been compared with the secondary drinking water standards and discussed at the point of characteristics of the local area and purpose of use of the water sample. Among the total of 298 samples, 2 samples exceed the secondary drinking water standards of EPA, 0.64% rate. Community drinking water and simplified water service showed relatively high detection rate and groundwater gave relatively higher concentration of silver indicating anthropogenic source and natural source could contribute simultaneously on groundwater.

• Journal of Microbiology and Biotechnology
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• v.33 no.1
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• pp.106-113
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• 2023

The supply of microbiological risk-free water is essential to keep food safety and public hygiene. And removal, inactivation, and destruction of microorganisms in drinking water are key for ensuring safety in the food industry. Ultraviolet-C (UV-C) irradiation is an attractive method for efficient disinfection of water without generating toxicity and adversely affecting human health. In this study, the disinfection efficiencies of UV-C irradiation on Shigella flexneri (Gram negative) and Listeria monocytogenes (Gram positive) at various concentrations in drinking water were evaluated using a water purifier. Their morphological and physiological characteristics after UV-C irradiation were observed using fluorescence microscopy and flow cytometry combined with live/dead staining. UV-C irradiation (254 nm wavelength, irradiation dose: 40 mJ/cm²) at a water flow velocity of 3.4 L/min showed disinfection ability on both bacteria up to 10⁸ CFU/4 L. And flow cytometric analysis showed different physiological shift between S. flexneri and L. monocytogenes after UV-C irradiation, but no significant shift of morphology in both bacteria. In addition, each bacterium revealed different characteristics with time-course observation after UV-C irradiation: L. monocytogenes dramatically changed its physiological feature and seemed to reach maximum damage at 4 h and then recovered, whereas S. flexneri seemed to gradually die over time. This study revealed that UV-C irradiation of water purifiers is effective in disinfecting microbial contaminants in drinking water and provides basic information on bacterial features/responses after UV-C irradiation.

• Environmental Engineering Research
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• v.24 no.3
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• pp.501-512
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• 2019

The seasonal effects on the biostability of drinking water were investigated by comparing the seasonal variation of assimilable organic carbon (AOC) in full-scale water treatment process and adsorption of AOC by three filling materials in lab-scale column test. In full-scale, pre-chlorination and ozonation significantly increase $AOC_{P17\;(Pseudomonas\;fluorescens\;P17)}$ and $AOC_{NOX\;(Aquaspirillum\;sp.\;NOX)}$, respectively. AOC formation by oxidation could increase with temperature, but the increased AOC could affect the biostability of the following processes more significantly in winter than in warm seasons due to the low biodegradation in the pipes and the processes at low temperature. $AOC_{P17}$ was mainly removed by coagulation-sedimentation process, especially in cold season. Rapid filtration could effectively remove AOC only during warm seasons by primarily biodegradation, but biological activated carbon filtration could remove AOC in all seasons by biodegradation during warm season and by adsorption and bio-regeneration during cold season. The adsorption by granular activated carbon and anthracite showed inverse relationship with water temperature. The advanced treatment can contribute to enhance the biostability in the distribution system by reducing AOC formation potential and helping to maintain stable residual chlorine after post-chlorination.

• Journal of Preventive Medicine and Public Health
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• v.10 no.1
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• pp.59-61
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• 1977

We are calling the erupting ground water as drugwater or mineral water in Korea and thinking those water is good for health from ancient. But most of them were used by mountainer as drinking water and food making water. Authors tried to investigate the evidence of contamination by user on the 10 erupting ground water and gained following results: 1. All of the mineral, waters on 10 area in Seoul were unfitable to drinking water standard. 2. In the view of the bacteriology 80% were contaminated by coliform group. 3. The highest value of the free carbon dioxide contents were 652.96 ppm at Sam Sun Mineral Water.

• Journal of Korean society of Dental Hygiene
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• v.10 no.3
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• pp.483-493
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• 2010

Objectives : The purpose of this study was to obtain the information for the improvement of the support in oder to expand the adjusted water fluoridation program to Myeong-dong water treatment plant in Gimhae city, Korea. Methods : Questionnaires were distributed to the parents of elementary schoolchildren and their responses were collected. All collected data were analyzed using the SPSS program. Results : The percentage of respondents using the tap water was 47.0% for drinking and 54.4% for cooking, respectively. The percentage of respondents using the water purified the tap water with the home water purifier was 45.1% for drinking and 36.2% for cooking, respectively. Respondents who knew the adjusted water fluoridation program was 48.3%. Respondents who knew the implementation of the adjusted water fluoridation program at the moment in Gimhae was 27.0%. 90.2% of residents agreed on the expansion of the adjusted water fluoridation program to Myeong-dong water treatment plant, Significant variables in the approval rates of the adjusted water fluoridation program were age, residence period, occupation, recognition of the program. Conclusions : It is desirable to expand the adjusted water fluoridation program to Myeong-dong water treatment plant in Gimhae as the percentage of respondents who agreed on the introduction of the program was high.