• 상하수도학회지
• /
• 제34권1호
• /
• pp.35-43
• /
• 2020

Turbidity has various effects on the water quality and ecosystem of a river. High turbidity during floods increases the operation cost of a drinking water supply system. Thus, the management of turbidity is essential for providing safe water to the public. There have been various efforts to estimate turbidity in river systems for proper management and early warning of high turbidity in the water supply process. Advanced data analysis technology using machine learning has been increasingly used in water quality management processes. Artificial neural networks(ANNs) is one of the first algorithms applied, where the overfitting of a model to observed data and vanishing gradient in the backpropagation process limit the wide application of ANNs in practice. In recent years, deep learning, which overcomes the limitations of ANNs, has been applied in water quality management. LSTM(Long-Short Term Memory) is one of novel deep learning algorithms that is widely used in the analysis of time series data. In this study, LSTM is used for the prediction of high turbidity(>30 NTU) in a river from the relationship of turbidity to discharge, which enables early warning of high turbidity in a drinking water supply system. The model showed 0.98, 0.99, 0.98 and 0.99 for precision, recall, F1-score and accuracy respectively, for the prediction of high turbidity in a river with 2 hour frequency data. The sensitivity of the model to the observation intervals of data is also compared with time periods of 2 hour, 8 hour, 1 day and 2 days. The model shows higher precision with shorter observation intervals, which underscores the importance of collecting high frequency data for better management of water resources in the future.

• Journal of Preventive Medicine and Public Health
• /
• 제26권2호
• /
• pp.192-201
• /
• 1993

Epidemiologic investigation was conducted on January, 1993 in Seoul to identify the cause of an infant methemoglobinemia. Field investigation of the area of outbreak, survey of household and family members, analysis of ground water, and blood tests of involved family members were performed. Following results were obtained On analyzing the quality of the ground water on patient's household high levels of nitrate was found indicating contamination of water as the cause of a methemoglobinemia outbreak. On analysing the quality of the ground waters on seven other places within the neighborhood five were contaminated by nitrate in concentration that exceeded the permissible limit implying presence nearby source of contamination. Sources of contamination were thought to be originating from human waste in conventional bathroom facilities, chicken manure used in nearby orchards and plant fields or fertilizers. But the results of water analysis with presence of bacteria or E.coli, concentration of potassium, phosphate and the past history of diarrhea among family members, chicken manure suggested the most possible source of contamination. To evaluate the health status of members in the neighborhood past history was reviewed revealing no prior existence of patient with cyanosis and 65 people in the neighborhood had normal levels of methemoglobin concentration in their blood. Conclusively, the ground water on patient's household was contaminated with nitrate and despite provision of adequate water supply, family members of the patient along with their distrust in the water supply system had used ground water as their source of drinking water resulting of methemoglobinemia. Many suburban area of Seoul and country side thought to be having similar problems concerning contaminated ground water supply and dormant outbreak of patients as a result of the drinking of the contaminated water. Epidemiologic investigation and water analysis of ground waters are advised.

• 한국환경농학회지
• /
• 제30권3호
• /
• pp.281-287
• /
• 2011

연구에서는 국내 유통 중인 먹는샘물에서의 보관 기간에 따른 formaldehyde 및 acetaldehyde를 DNPH로 유도체화하여 HPLC/UV로 분석하였다. 먹는샘물 79개 제품에 대하여 검출 현황을 조사하였으며, 그 중 9개 제품에 대해 180일 기간 동안 경과 일수에 따른 온도 및 보관 재질에 따른 formaldehyde 및 acetaldehyde의 농도 변화를 조사하여 먹는샘물의 안전관리 방안을 모색하고자 하였다. 먹는샘물 79개 제품에 대한 검출 현황을 조사한 결과 formaldehyde는 평균농도 $3{\mu}g/L$, 농도 범위는 $0{\sim}29{\mu}g/L$로 나타났으며, acetaldehyde는 평균농도 $20{\mu}g/L$, 농도 범위는 $0{\sim}154{\mu}g/L$로 나타났다. 검출된 제품의 대부분은 오존처리를 하는 것으로 나타났으며, 산화반응에 의해 오존과 반응하여 formaldehyde와 acetaldehyde가 발생한 것으로 사료된다. 보관 기간에 따른 온도 및 재질별 formaldehyde와 acetaldehyde 농도 변화를 조사한 결과, PET병에 담긴 먹는 샘물은 대부분 제품에서 증가하는 경향을 보였다. 특히, $50^{\circ}C$ PET병의 시료는 180일 경과할 때까지 formaldehyde 및 acetaldehyde 모두 꾸준히 증가하는 것으로 나타났으며, 유리병의 시료는 $25^{\circ}C$, $50^{\circ}C$에서 모두 미량의 농도로 검출되었으며 보관 기간에 따라 큰 변화는 없는 것으로 나타났다. 이 결과로 볼 때 formaldehyde 및 acetaldehyde 농도는 PET 병과의 접촉시간 및 온도의 영향을 받아 증가하는 것으로 나타나며, 높은 온도에서는 PET병으로부터 aldehyde가 형성 및 물로 이동 과정을 통하여 증가되는 것으로 사료된다. 먹는 샘물 생산 공정 중 소독제의 종류 및 사용, 유통기한, 보관방법 등에 대한 종합적인 관리제도가 필요할 것으로 생각되며 보존과정에서 증감되는 미량유해물질에 대한 추가 연구가 필요할 것으로 사료된다.

• 보건교육건강증진학회지
• /
• 제27권4호
• /
• pp.113-121
• /
• 2010

Objectives: The study sought to identify the perception of schoolchildren's parents concerning an approval on the expansion implementation of community water fluoridation program in Gimhae, Korea. Methods: Questionnaires were distributed to schoolchildren's parents in Gimhae in 2008. Responses were collected from 1,703 parents. The standard questionnaire of Ministry of Health and Welfare was used and items were socioeconomic variables, water used for drinking and cooking, awareness on the fluoridation program and approval on the expansion implementation of fluoridation program at the region of Myeongdong water plant. Significance was analyzed by chi-square test and multiple logistic analysis. Results: Of parents, 1.9% used plain tap water and 39.8% used boiled tap water for drinking and 50.0% used tap water for cooking. 58.0% of parents were aware of fluoridation program with 27.1% being aware of the implementation of the program in Gimhae. 74.5% approved the expansion implementation of the program to the region of Myeong-dong water plant. Significant variables associated to approving the expansion implementation of program were age, gender, residence period in Gimhae, occupation and awareness of the program. Conclusion: The expansion implementation of fluoridation program in Gimhae is desirable for caries prevention because of the majority of schoolchildren's parents' approval.

• 한국환경보건학회지
• /
• 제19권2호
• /
• pp.16-22
• /
• 1993

In recent years, great concern for the improvement of drinking water quality has been arising due to the contamination of the raw and treated water. So trihalomethanes (THMs) and some other volatile organic compounds (VOCs), potential carcinogenic substances, rendered the government to take some countermeasurements for clean water service in the dimension of public health. In this study, we used liquid-liquid extraction method as a rapid simple method for determination of VOCs through eluation with n-Pentane in water. The aim with the present study has been to determine the changes of recovery and reproducibility of the method under the various conditions in extraction solvents, solvent ratio and extraction time, and to observe the concentrations under the various temperature and pH during storage.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
• /
• pp.430-433
• /
• 2003

Nitrogen pollution in urban and rural groundwater is a common problem and poses a major threat to drinking water supplies based on groundwater. In this work, the kinetics of nitrification-denitrification coupled reactions are modeled and new reaction modules for the RT3D code describing the fate and transport of nitrogen species, dissolved oxygen, dissolved organic carbon, and biomass are developed and tested. The proposed nitrogen transformations and transport model showed very good match with the results of other public codes.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 1997년도 추계 국제학술심포지움 논문집
• /
• pp.3-31
• /
• 1997

Water has always played a significant role in the lives of people. In urbanised Rome, with its million people. sophisticated supply systems developed and then fled with the empire. only to be rediscovered later But it was the industrial Revolution commencing in the eighteenth century that ushered in major paradigm shifts In use and altitudes towards water. Rapid and concentrated urbanisation brought problems of expanded demands for drinking supplies, waste management and disease. The strategy of using water from local streams, springs and village wells collapsed under the onslaughts of rising urban demands and pollution due to poor waste disposal practices. Expanding travel (railways. and steamships) aided the spread of disease. In England. public health crises peaks, related to water-borne typhoid and the three major cholera outbreaks occurred in the late eighteenth and early nineteenth century respectively. Technological, engineering and institutional responses were successful in solving the public health problem. it is generally accepted that the putting of water into pipe networks both for a clean drinking supply, as well as using it as a transport medium for removal of human and other wastes, played a significant role in towering death rates due to waterborne diseases such as cholera and typhoid towards the end of the nineteenth century. Today, similar principles apply. A recent World Bank report Indicates that there can be upto 76％ reduction in illness when major water and sanitation improvements occur in developing countries. Water management, technology and thinking in Australia were relatively stable in the twentieth century up to the mid to late 1970s. Groundwater sources were investigated and developed for towns and agriculture. Dams were built, and pipe networks extended both for supply and waste water management. The management paradigms in Australia were essentially extensions of European strategies with the minor adaptions due to climate and hydrogeology. During the 1970s and 1980s in Australia, it was realised increasingly that a knowledge of groundwater and hydrogeological processes were critical to pollution prevention, the development of sound waste management and the problems of salinity. Many millions of dollars have been both saved and generated as a consequence. This is especially in relation to domestic waste management and the disposal of aluminium refinery waste in New South Wales. Major institutional changes in public sector water management are occurring in Australia. Upheveals and change have now reached ail states in Australia with various approaches being followed. Market thinking, corporatisation, privatisation, internationalisation, downsizing and environmental pressures are all playing their role in this paradigm shift. One casualty of this turmoil is the progressive erosion of the public sector skillbase and this may become a serious issue should a public health crisis occur such as a water borne disease. Such crises have arisen over recent times. A complete rethink of the urban water cycle is going on right now in Australia both at the State and Federal level. We are on the threshold of significant change in how we use and manage water, both as a supply and a waste transporter in Urban environments especially. Substantial replacement of the pipe system will be needed in 25 to 30 years time and this will cost billions of dollars. The competition for water between imgation needs and environmental requirements in Australia and overseas will continue to be an issue in rural areas. This will be especially heightened by the rising demand for irrigation produced food as the world's population grows. Rapid urbanisation and industrialisation in the emerging S.E Asian countries are currently producing considerable demands for water management skills and Infrastructure development. This trend e expected to grow. There are also severe water shortages in the Middle East to such an extent that wars may be fought over water issues. Environmental public health crises and shortages will help drive the trends.

• 한국환경보건학회지
• /
• 제40권2호
• /
• pp.88-97
• /
• 2014

Objectives: The aim of this study was to evaluate the occurrence of microbiological contamination of kitchen utensils and environments of food service operations at university located in Seoul, Korea. Methods: We collected swab samples from the surfaces of knives, chopping boards, floors, and drains, as well as drinking water and airborne bacteria samples from 20 food service operations. Three bacterial indicators and five food poisoning bacteria were measured quantitatively and qualitatively, respectively. We used selective culture media and the PCR assay targeting 16S rRNA gene for the microbiological analysis. Results: We detected bacterial indicators on knives or chopping boards in eight different food service operations and, three food service operations (I, M, and O) showed more than 3 log colony forming units $(CFU)/100cm^2$ on their knives, significantly higher than the others. The levels of bacterial indicators on the floors and drains in the cooking areas were much higher than those on the cooking utensils. S. aureus was detected on 10 floors and 8 drains. Culturable bacteria were identified in 5 drinking water samples, and food service operation B ($431.1CFU/m^3$) and C ($551.2CFU/m^3$) showed more than $400CFU/m^3$ of total airborne bacteria. Conclusions: These results suggest that some of food service operations in this study may require additional investigation to secure the microbial safety of cooking environments. In addition, further actions including hygiene education for employees and proper guidelines to maintain clean cooking environments should be prepared.

• Korean Chemical Engineering Research
• /
• 제51권6호
• /
• pp.645-654
• /
• 2013

본 논문에서는 국내 외 미량오염물질의 관리현황을 분석하고, 기후변화 등 수질관리에 영향을 주는 잠재적인 요소를 고려한 미량오염물질의 관리방향을 제시하고자 하였다. 국내에서는 먹는 물 안전성 확보를 위해 수돗물 정수 및 원수를 대상으로 미량오염물질에 대한 실태조사가 꾸준히 진행되었다. 근래에 들어 하천 호소수 중의 미량오염물질에 대해서도 조사가 진행되고 있으나 조사 항목과 횟수가 많지 않아 전체적인 미량오염물질 발생 및 검출 현황을 파악하기에는 어려움이 있었다. 선진국에서는 미량오염물질의 실태조사 외에도 환경 매체에서의 거동, 인체 및 생태위해성, 처리공정 등에 미량오염물질 관리 전반에 대한 연구가 수행되고 있음을 확인할 수 있었다. 향후 기후변화에 따른 기온과 수온의 상승, 수문학적인 순환의 변화 등으로 미량오염물질의 잔류 농도가 증가할 우려가 있다. 또한 물 재이용이 확대되는 과정에서 미량오염물질에 대한 우려가 커질 수 있다. 그러므로 먹는 물 또는 신체와 접촉하는 용도의 용수에 대해서는 사전예방의 관점에서 미량오염물질의 관리를 강화하는 것이 필요하다. 지표수 중의 미량오염물질에 대해서는, 물환경 정책목표 중의 하나인 생태 위해성 관리의 관점에서, 물질의 거동, 생태 위해성 평가, 하 폐수처리공정에서의 제어방안 등에 대한 연구가 확대되어야 할 것이다.

• Journal of Nutrition and Health
• /
• 제27권10호
• /
• pp.1037-1047
• /
• 1994

Dietary iodine intake and urinary iodide excretion were meassured from 110 patients with various thyroid hormone diseses(hypothyroidism, hyperthyroidism, simple goiter and thyroid adenoma) and 67 normal control subjects. Iodine intake was assessed on the 24-hour recall dietary data using the compiled lists of food iodine values developed from various countries. Urinary iodide concentrations of drink water samples were measured with the iodide-selective electrode. The average iodine intake of the thyroid patients was 411$\mu\textrm{g}$, which was 87% higher(p<0.05) than that of the control subjects(220$\mu\textrm{g}$). Patients with hyperthyroidism and hypothyroidism or simple goiter excreted the most(0.6442ppm) amount of iodide respectively in the urine, with the control subject in the middle(0.5229ppm). Iodide concentrations of the drinking water samples were found to be in the range of 0.0015ppm to 0.0214ppm, which seemed to vary depending on the kind(underground water vs public water) and the location.