• 한국물환경학회지
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• 제27권4호
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• pp.467-474
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• 2011

In an effort to investigate water pollution characteristics of Juam lake, water samples were collected from three sites (Sites A, B, and C) of Oenam stream which is a typical tributary of rural watershed in the lake and analyzed for N concentration and the corresponding isotope ratio (${\delta}^{15}N$) of ${NO_3}^-$. Concentrations of ${NO_3}^-$ were not dramatically different among the sites; $0.8{\pm}0.2mgNL^{-1}$ (range: $0.0{\sim}4.3mgNL^{-1}$) for Site A, $1.1{\pm}0.2mgNL^{-1}$ ($0.0{\sim}4.3mgNL^{-1}$) for Site B, and $1.1{\pm}0.1mgNL^{-1}$ ($0.1{\sim}2.6mgNL^{-1}$) for Site C. Meanwhile, ${\delta}^{15}N$ tended to decrease with river flow; it was highest for Site A ($45.5{\pm}5.3$‰) followed by Site B ($19.7{\pm}2.0$‰) and Site C ($8.7{\pm}1.5$‰). Such high ${\delta}^{15}N$ values of ${NO_3}^-$ in Site A suggested that ${NO_3}^-$ derived from livestock feedlot (specifically livestock excrete of which ${\delta}^{15}N$ is higher than 10‰) is the predominant pollution sources despite mountainous area occupied the most of land-use in the watershed. Using the two-sources isotope mixing model, it was estimated that the contribution of cropping activities (i.e. fertilization) became greater in down-stream area (Sites B and C) due to the higher agricultural land-use than the up-stream area (Site A). Particularly, during the active cropping season, the low contribution of organic pollution sources indicated that domestic sewage was not the predominant pollution source. Therefore, it was suggested that agricultural sources such as livestock farming and cropping rather than mountainous and residential are the dominant sources of water pollution in the study area. These results could be effectively utilized in elucidating water pollution sources in rural areas and selecting water management practices.

• 멤브레인
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• 제30권3호
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• pp.190-199
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• 2020

2018년 환경부에서 발표된 수도정비기본계획에 따라 다양한 수자원 활용의 중요성이 증가하고 있으며, 여러 수원을 혼합하여 원수 또는 생산수로 활용하는 워터 블렌딩 방식은 미국, 호주를 비롯한 여러 나라에서 시도되고 있다. 본 연구에서는 공업용수 공급 목적으로 100,000 ㎥/일 규모 해수담수화 사업이 추진되고 있는 충남 대산 지역을 대상으로, 해수와 호소수, 침전수, 폐수 방류수 등 타 수원을 블렌딩할 때 수종 및 혼합비율에 따른 영향을 분석하였다. 타 수원 혼합비율 10~50% 조건에서 혼합수 염분농도는 약 50%까지 감소하였지만, 탁질 및 유기물 농도는 1.6~2.0배 수준으로 증가하는 것을 확인하였다. 실험실 규모 역삼투 공정 성능평가 결과, 해수의 단독활용 대비 원수 혼합 시 막오염 경향이 증가하였으며 혼합비율 10~50%에서 평균 4.1배의 플럭스 저감률을 나타내었다. 성능모사를 통한 역삼투 공정 성능분석에 따르면 혼합비율 50% 조건에서 역삼투 공정 에너지 사용량이 평균 39% 절감될 수 있을 것으로 기대되나, 운영비용 등 혼합수 활용에 대한 전반적인 영향분석을 위해서는 모형플랜트 규모에서 장기간 성능평가가 필요하다.

• 환경위생공학
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• 제20권3호
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• pp.51-56
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• 2005

Allocation of water pollution load from loading capacity can be much essential, controversial, and its standards can be applied case-by-case to the various situations. Allocation methods to point sources are generally 'Equal effluent concentration', 'Equal percent Treatment', Loading capacity at planning stage consists of basic pollution load, development pollution load, reserved pollution load and margin of safety. But at the implementing stage loading capacity can be consisted of allocatable load and margin of safety to give more flexibility in the total water pollution load management plan. In that case, we can re-adjust and altogether use the pollution load of point sources of series and non-point sources at the implementing stage.

• 한국물환경학회지
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• 제31권2호
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• pp.159-165
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• 2015

The organic matter sources of phytoplankton and related environmental factors influencing algal bloom in Paldang reservoir were studied using nitrogen and carbon isotope ratio(${\delta}^{15}N$, ${\delta}^{13}C$). Phytoplankton samples for stable isotope analysis were collected from four points in reservoir using a plankton net. Physicochemical water quality, algal taxa and hydrological data were collected from published monitoring material. Phytoplankton samples were analyzed by IRMS. CN ratio of each sample was very similar to that of phytoplankton from literature cited. ${\delta}^{15}N$ of each sample was decreased during July. Mixing and dilution of nitrogen sources due to increment of influx by concentrated rainfall were considered as the main reason for the decline of ${\delta}^{15}N$. Based on analyzed ${\delta}^{15}N$ value of each sample, nitrogen source of Bughan river sample was presumed to come from soil. The nitrogen sources of Namhan river and Kyeongan stream samples seemed to be sewage or animal waste. Low ${\delta}^{15}N$ value in August (2012) seemed to be influenced by isotope fractionation due to the blooming of nitrogen-fixation blue-green algae (Anabaena spp.). Variation in ${\delta}^{15}N$ values particularly by blue-green algal bloom was considered the important factor for estimating the organic matter sources of phytoplankton.

• 한국물환경학회지
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• 제22권6호
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• pp.1075-1081
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• 2006

In this research, mortality rates of pathogen indicator microorganisms discharged from various point sources and diffuse sources in urban area were measured. Water samples were taken at domestic sewer, combined sewer overflow, effluent from a wastewater treatment plant, urban river, and sediment of an urban river. Mortality rates of indicator microorganisms in domestic sewer estimated by assuming the first order kinetics at $20^{\circ}C$ were as follows: total coliform = 0.092/day, fecal coliform = 0.185/day, E. coli = 0.252/day, and fecal streptococci = 0.281/day. Sensitivity of mortality rates of total coliform on temperature was estimated as $K_{temp}=K_{20}{\times}1.162^{(temp-20)}$ for the range of $10-20^{\circ}C$. Mortality rates due to sunlight were measured as 1.22-1.59/day while mortality rate due to settling for 40 min were estimated as $9.21{\times}10^3-20.0{\times}10^3/day$.

• 상하수도학회지
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• 제8권3호
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• pp.34-40
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• 1994

Industrial Complex in Ulsan is one of the most important areas in the nation. It includes ship building, automobile production, petroleum industry, non-metalic industry, and related industries. However, water for drinking and industry use has been and will be short seriously. Thus available drinking water sources were searched. By rebuilding the two existing dams 20m higher than the present levels, $500,000m^3/day$(for 200days) of water sources may be produced. Additional volume of $13,000m^3/day$(for 200days) can be obtained by a number of small dam construction in the vincity area. Underground water of about $50,000m^3/day$ may also be available. The total of $680,000m^3/day$ could be produced in Ulsan area, which is enough for the population of 1,200,000 in Ulsan area even after year 2011. This newly searched volume of water may be free from pollution. Raising the dam levels may also prevent Ulsan city from chronic flooding problems. Additional advantage is that as much as the newly developed water resources can be supplied to the industrial complexes.

• Environmental Analysis Health and Toxicology
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• 제28권
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• pp.9.1-9.5
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• 2013

Objectives Geographic Information Systems (GIS) is a powerful tool for assessing exposure in epidemiologic studies. We used GIS to determine the geographic extent of contamination by perfluorooctanoic acid, C8 (PFOA) that was released into the environment from the DuPont Washington Works Facility located in Parkersburg, West Virginia. Methods Paper maps of pipe distribution networks were provided by six local public water districts participating in the community cross-sectional survey, the C8 Health Project. Residential histories were also collected in the survey and geocoded. We integrated the pipe networks and geocoded addresses to determine which addresses were serviced by one of the participating water districts. The GIS-based water district assignment was then compared to the participants' self-reported source of public drinking water. Results There were a total of 151,871 addresses provided by the 48,800 participants of the C8 Health Project that consented to geocoding. We were able to successfully geocode 139,067 (91.6%) addresses, and of these, 118,209 (85.0%) self-reported water sources were confirmed using the GIS-based method of water district assignment. Furthermore, the GIS-based method corrected 20,858 (15.0%) self-reported public drinking water sources. Over half (54%) the participants in the lowest GIS-based exposure group self-reported being in a higher exposed water district. Conclusions Not only were we able to correct erroneous self-reported water sources, we were also able to assign water districts to participants with unknown sources. Without the GIS-based method, the reliance on only self-reported data would have resulted in exposure misclassification.

• 한국수산과학회지
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• 제44권6호
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• pp.612-621
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• 2011

The influences of inland pollution sources because of rainfall events on the bacteriological water quality in Geoje Bay, a major shellfish production area in Korea, were investigated. The sanitary status of sea water and shellfish after rainfall events was also evaluated. The flow rates of 13 streams around Geoje Bay showed 6 to 7-fold increases after 15 to 21 mm of rainfall. Peak pollution was observed in the Naegan Stream, the Gandeok Stream and the Seojeong Stream. The calculated impact area of inland pollution sources was 3.1 $km^2$ immediately after 15 mm of rainfall and expanded to 3.5 $km^2$ after 24 hours. These calculations of impacted area matched results from fecal coliform analyses with sea water. The distance between the major pollution source in the bay (the Gandeok Stream) and the station with the worst bacteriological water quality immediately after 15 mm of rainfall, which was below the Korean standard, was 0.8 km in a straight line; this distance increased to 2.0 km after a period of 24 hours. The area impacted by inland pollution sources after a 15 mm rainfall event was wider than after a 21 mm rainfall. Although the flow rate from inland pollution sources was higher, the concentration of fecal coliform in the discharged water was lower after higher rainfall events. These observations corresponded with the results of fecal coliform analyses with sea water samples. According to the evaluation of the influences of inland pollution sources and fecal coliform analyses on sea water and shellfish samples in Geoje Bay, pollutants from inland sources did not reach the boundary line of the shellfish growing area after rainfall events of 15 or 22 mm. The bacteriological water quality of the shellfish growing area in Geoje Bay met the Korean standard and US NSSP requirements for approved shellfish growing areas.

• 천문학회보
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• 제38권2호
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• pp.77.2-77.2
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• 2013

We present the interim results of simultaneous time monitoring observations of $^{28}SiO$ v = 1, 2, J = 1-0, $^{29}SiO$ v = 0, J = 1-0 and $H_2O$ $6_{16}-5_{23}$ maser lines toward 10 known water fountain sources at a post-AGB stage. The observations have been carried out from 2009 June to 2013 September using the 21m single dish radio telescopes of the Korean VLBI Network. From six sources, we detected well separated red- and blue-shifted $H_2O$ maser features with large velocity ranges more than 100 km $s^{-1}$. From four sources, we detected red- and/or blue-shifted $H_2O$ maser features depended on observational epochs. However, we could not detected SiO maser emission from any sources and any epochs. For a representative water fountain source W43A, we obtained $H_2O$ maser spectra at 17 epochs which show a clear bipolar and discontinuous mass ejections. They also showed a periodic change between red-shifted and blue-shifted peaks. However, we need a more regular and short-time interval monitoring observations in order to fix the period and peak intensity variation interval.

• 환경위생공학
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• 제6권1호
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• pp.7-25
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• 1991

Until now, pure drinking water grnerally menas the water without taste, odor, general bacteria, coliform, and other exotic substance. Such a definition has been changing recently due to the finding of numerous other inorganic and organic substances unknown to us. 10 years ago, major causes of death were infectious agents and parasites contained in water, but recently, it has become apparent that some substances contained in drinking water cause cancer and heart diseases. We must drink about 2L of water everyday in order to maintain healthy condition. Waters used for drinking include tap water, well water, spring water, filtered water, etc., but the quality of drinking water has more polluted due to the industrial development and population increase. For example, industrial waste waters from industrial plants pollute the water supply sources ; toxic substances contained in the waste waters pollute the ground water sources by penetrating the geological strata, and municipal, livestock, public building waste waters also pollute the water supply sources. Sometimes, the polluted surface waters were announced to be polluted by various kinds of orgainc substance, and it is reported that the pollution of ground water by orga nic substances has few in number but high in its concectration comparing with those of surface water. As the water quality pollution level increases, so the amount of disinfectant also increase. For example, chlorine solution, one of widely used disinfectants, creates trihalomethane(THM), a carcinogen, and halogen compounds. According to Oliver, through chlorine disinfection process, humine substance and chlorine create bolatile organic halide and nonvolatile organic halide by chemical reaction. There are tens or hundreds filtering devices, but filtering principles and maintenance metjhods are different, so their efficiency tests are needed. According to Smith, the effeciency tests aginst over 30 Ameican filtering devices show that 10 devices can remove 85% of volatile organics and further studies on filtered waters are underway. In consideration of important impacts of polluted drinking water on national health, authors studied the state of water quality pollution against tap water used as drinking water, filtration device passed water, ground water, and conserved drinking water ; tested the efficiency of filtration devices for tap water ; tried to sep up the detection method by using ion chromatography based on negative ion and positive ion by using single column, and attemped the simple filtration method for general households.