• 대한지리학회지
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• 제48권3호
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• pp.336-347
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• 2013

This paper presents an evaluation of stream restoration projects in Seoul with a focus on dissolved oxygen. Five test sites across four streams were measured for dissolved oxygen (DO) in late May to early June in 2012 and compared against a set of minimum and maximum thresholds. Only one test site, Hwarang-cheon, showed measurements below 6 mg/l DO. Towards the upper limit, the Hwarangcheon site was the only tested stream which was not at risk of DO supersaturation. The Danghyeon-cheon site had the highest probability of supersaturation, with DO saturation exceeding 130% expected 86.5% of the time. When measured every hour during daytime, DO levels showed diurnal variations, peaking in the afternoon. However, they showed inconsistent results along transects of the streams. Overall, the streams are rich in DO. To maintain the streams in good standing, nutrient loading should be addressed to prevent potential algal bloom induced hypoxic events down the line.

• 한국물환경학회지
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• 제28권2호
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• pp.213-218
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• 2012

Abnormal dissolved oxygen concentration in aquatic habitat, both depletion and supersaturation, can be stress factor to aquatic animals. In this study the nationwide distribution of oxygen supersaturation was analyzed for three categories of streams (43 urban streams, 15 rural streams, and 14 forest streams) by using monitoring network data of the Korean Ministry of Environment. From the distribution analysis 30% of urban streams showed hyperoxic condition of eutrophic level, while no forest stream showed hyperoxic condition. The physiological effect of hyperoxia on fish was examined using two species of fish Zacco koreanus, which resulted in higher concentration of a stress hormone (cortisol) in fish exposed to hyperoxic concentration (196%) of oxygen. This study shows that hyperoxic condition is ubiquitous in urban and rural Korean streams, and it can be a stress factor to aquatic animals.

• Journal of Oral Medicine and Pain
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• 제20권1호
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• pp.7-18
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• 1995

The Purpose of this article is to describe the biochemical properties and biological functions of several salivary proteins that possess the unusual properties of inhibiting spontaneous and secondary precipitation of calcium phosphate. This function is very important since human salivary secretion is supersaturated with respect to calcium phosphate. Biological function of statherin, proline rich protein (PRP) and histidine rich protein (HRP) is to inhibit precipitation of calcium phosphate in salivary glands, in the oral fluids, and onto tooth surfaces. The resulting supersaturated state of the salivary secretions contributes a protective and reparative environment which is important for the integrity of the tooth. Beneficial consequences of salivary supersaturation with respect to calcium phosphate are selectively expressed in the oral cavity- that is, protection is provided for the dental enamel-while undesirable consequences, for example, precipitation of calcium phosphates in the salivary glands and onto the teeth do not occur. Purification and structural characteristics of these proteins as well as clinical significance of functions of each protein will be discussed.

• Ecology and Resilient Infrastructure
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• 제6권2호
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• pp.109-119
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• 2019

국내의 많은 저수심 저수지들은 다양한 수질오염물질의 유입으로 인해 부영양화가 진행되고 있으며, 해마다 반복적으로 표층의 녹조 발생과 저층의 빈산소화를 겪고 있다. 이를 방지하기 위한 대책으로 저수지의 성층현상을 완화하는 기존 기술들이 있으나 대부분 동력이 필요하며 비경제적인 측면으로 인해 도입이 어려운 실정이다. 본 연구에서는 바람과 수류의 자연에너지를 활용하는 무동력 수류순환시스템을 개발하고 상이한 조건을 갖는 두 저수지를 대상으로 테스트베드를 구축, 운영하여 현장적용성을 검토하였다. 수류순환시스템을 모사한 전산유체역학 (CFD) 모의 결과, 하향류가 유도되어 표층과 심층 사이의 성층현상을 완화시키고, 영향반경은 약 30 m에 달하는 것으로 해석되었다. 테스트베드에 대한 장기 모니터링 결과, 수류순환 작용에 의해 DO의 변동을 완만하게 하고, DO 과포화 현상을 저감하며, pH의 과도한 상승을 방지하는 등 다양한 수질개선 효과가 관찰되었다. 본 수류순환시스템의 현장적용성을 제고하기 위해서는 홍수시 및 저수심 조건에 대한 대응방안 마련이 필요한 것으로 판단된다.