• 한국지하수토양환경학회지:지하수토양환경
• /
• 제18권3호
• /
• pp.109-118
• /
• 2013

Characteristics of the transport of zero-valent iron nanoparticles (nZVI) in an aquifer were investigated to evaluate an application of nZVI-based reactive zone technology. Main flow direction of groundwater was north. Preferential flow paths of the groundwater identified by natural gradient tracer test were shown northeast and northwest. The highest groundwater velocity was $4.86{\times}10^{-5}$ m/s toward northwest. When the breakthrough curves obtained from the gravity injection of nZVI were compared with the tracer curves, the transport of nZVI was retarded and retardation factors were 1.17 and 1.34 at monitoring wells located on the northeast and northwest, respectively. The ratios of the amount of nZVI delivered to the amount of tracer delivered at the two wells mentioned above were 24 and 28 times greater than that of the well on the main flow direction, respectively. Attachment efficiency based on a filtration theory was $4.08{\times}10^{-2}$ along the northwest direction that was the main migration route of nZVI. Our results, compared to attachment efficiencies obtained in other studies, demonstrate that the mobility of nZVI was higher than that of results reported in previous studies, regardless of large iron particle sizes of the current study. Based on distribution of nZVI estimated by the attachment efficiency, it was found that nZVI present within 1.05 m from injection well could remove 99% of TCE within 6 months.

• 한국환경생태학회지
• /
• 제17권3호
• /
• pp.187-200
• /
• 2003

중국과 북한의 국경을 이루는 두만강 접경지역을 따라 중국 측에서 식물상을 조사하였다. 그 결과 92과 287속 470종 57변종 4품종, 총 531 분류군의 관속식물이 나타났다. 식물상 조사는 고층습지, 해안사구, 하천, 고산초원, 낙엽활엽수림, 상록침엽수림, 혼효림, 노방식물군 등 다양한 생태환경의 대상지에서 수행되었다. 본 조사지역에서 환경부가 지정한 보호식물로 솔나리, 산작약. 깽깽이풀, 가시오갈피, 대청부채, 큰연령초 등 6종이 조사되었으며 산림청 지정의 희귀 및 멸종위기식물은 노랑돌쩌귀, 창포, 끈끈이주걱, 부채붓꽃. 깽깽이풀, 날개하늘나리. 솔나리. 말나리, 산작약, 낙지다리, 모새달, 층층둥굴레, 붉은인가목, 흑삼릉, 백리향, 큰연령초, 통발, 덩굴용담, 들쭉나무, 월귤, 가시오갈피 등 21종이 나타났다. 조사된 관속식물 가운데 종비나무, 잎갈나무, 만주자작나무, 비술나무, 물황철나무, 백산차, 황산차, 닥장버들, 부전자작나무, 회령사초, 양뿔사초, 산부채, 하늘매발톱, 황기, 달구지풀, 방풍, 꽃고비, 황금, 린네풀, 왕과, 목향. 금혼초, 누른진범, 키다리바꽃. 끈끈이딱지꽃 등은 남한에 자생하지 않는 중국의 동북지역 특산식물로 조사되었다.

• 한국물환경학회지
• /
• 제36권6호
• /
• pp.508-520
• /
• 2020

Dam reservoirs have been reported to contribute significantly to global carbon emissions, but unlike natural lakes, there is considerable uncertainty in calculating carbon emissions due to the complex of emission pathways. In particular, the method of calculating carbon dioxide (CO2) net atmospheric flux (NAF) based on a simple gas exchange theory from sporadic data has limitations in explaining the spatiotemporal variations in the CO2 flux in stratified reservoirs. This study was aimed to analyze the spatial and temporal CO2 distribution and mass balance in Daecheong Reservoir, located in the mid-latitude monsoon climate zone, by applying a two-dimensional hydrodynamic and water quality model (CE-QUAL-W2). Simulation results showed that the Daecheong Reservoir is a heterotrophic system in which CO2 is supersaturated as a whole and releases CO2 to the atmosphere. Spatially, CO2 emissions were greater in the lacustrine zone than in the riverine and transition zones. In terms of time, CO2 emissions changed dynamically according to the temporal stratification structure of the reservoir and temporal variations of algae biomass. CO2 emissions were greater at night than during the day and were seasonally greatest in winter. The CO2 NAF calculated by the CE-QUAL-W2 model and the gas exchange theory showed a similar range, but there was a difference in the point of occurrence of the peak value. The findings provide useful information to improve the quantification of CO2 emissions from reservoirs. In order to reduce the uncertainty in the estimation of reservoir carbon emissions, more precise monitoring in time and space is required.

• 대한토목학회논문집
• /
• 제32권2B호
• /
• pp.131-137
• /
• 2012

현재의 하천구역구분은 평가자의 주관에 의해 경험적으로 보전, 복원 및 친수지구로 구분되고 있다. 보전지구를 구분할 때에는 하천의 자연성을 대상으로 하기 때문에 대부분 기술자들의 결과가 일치하지만, 복원지역과 친수구역을 구분할 때에는 도시하천과 전원하천이 혼재하는 경우 그 구분의 기준을 정하기기 어려운 실정이다. 따라서 본 연구에서는 하천구역을 구분하기 위해 우선 보전지구 정비지구로 구분하고 정비지구를 다시 복원지구와 친수지구로 구분하고자 한 기존 연구(송주일과 윤세의, 2008)의 적용성을 확인하기 위하여 경기도지역을 중심으로 20개 도시하천의 46개 구간, 29개 전원하천의 47개 구간, 19개 산지하천의 48개 구간 등 총 141개 구간에 대하여 평가를 수행하였다. 본 연구의 결과는 하천구역구분에서 보전지구, 복원지구 또는 친수지구를 구분하는데 합리적임을 알 수 있었다. 정량화된 기준에 따라 하천을 보전, 복원 및 친수지구로 지정할 수 있는 가능성을 제시하였다.

• 한국해양공학회지
• /
• 제22권3호
• /
• pp.8-17
• /
• 2008

Wrenching climatic changes due to ecocide and global wanning are producing a natural disaster. Coastal zones have been damaged by typhoons and accompanying storm surges. Severe waves, and destruction of the environment are adding to the severity of coastal disasters. There has been an increased interest in these coastal zone problems, and associated social confusion, after the loss of life and terrible property damage caused by typhoon Maemi. Especially if storm surges coincide with high ticks, the loss of life and property damage due to high waters are even worse. Therefore, it is desirable to accurately forecast not only the timing of storm surges but also the amount water level increase. Such forecasts are very important from the view point of coastal defense. In this study, using a numerical model, storm surge was simulated to examine its fluctuation characteristics for the coastal area behind Masan Bay, Korea. In the numerical model, a moving boundary condition was incorporated to explain wave run-up. Numerically predicted inundation regimes and depths were compared with measurements from a field survey. Comparisons of the numerical results and measured data show a very good correlation. The numerical model adapted in this study is expected to be a useful tool for analysis of storm surges, and for predicting inundation regimes due to coastal flooding by severe water waves.

• Journal of Ecology and Environment
• /
• 제43권2호
• /
• pp.104-116
• /
• 2019

Background: The composition of wild bird populations in temperate zones greatly varies depending on phenological changes rather than other environmental factors. Particularly, wild birds appearing in wetlands fluctuate greatly due to the crossover of species arriving for breeding during the summer and for wintering. Therefore, to understand the changes to species composition related to phenology, we conducted this basic analysis of populations to further the cause of the protection of wetland-dependent wild birds. Methods: It is wrong to simply divide a wild bird population investigation into seasons. This study identifies species composition and indicator species that change along with seasons. Wetlands to be surveyed are protected by natural monuments and wetland inventory and are in a state close to nature. In order to identify as many species as possible in wetlands, a survey was conducted in both shallow and deep wetlands. The water depth varied in these areas, ranging from 0.2 to 2.0 m, allowing for both dabbling and diving ducks to inhabit the area. Surveys were conducted using line-transect and distance sampling methods and were conducted at intervals of 2 weeks. The survey was conducted under the following three categories: the eco-tone and emergent zone, the submergent zone, and the water surface. The survey was conducted along a wetland boundary by observing wild birds. A PC-ord program was used for clustering, and the SAS program was used to analyze the changes in species composition. The data strongly indicates that day length is the main factor for seasonal migration periods, despite the fact that climate change and increasing temperatures are often discussed. Results and conclusions: The indicator species for determining seasons include migrant birds such as Ardea cinerea, Alcedo atthis, Anas penelope, and Poiceps ruficollis, as well as resident birds such as Streptopelia orientalis and Emberiza elegans. Importantly, increases in local individual counts of these species may also serve as indicators. The survey results of seasonal fluctuations in temperate zones shows that spring (April to June), summer (July to September), autumn (October), and winter (November to March) are clearly distinguishable, even though spring and summer seasons tend to overlap, leading to the conclusion that additional research could more clearly identify fluctuation patterns in species composition and abundance in the study area.

• 한국환경생태학회지
• /
• 제27권4호
• /
• pp.473-486
• /
• 2013

본 연구는 2011년 국립공원으로 편입된 다도해해상국립공원 팔영산지구의 식생구조와 식생천이계열을 파악하기 위하여 75개의 조사구(단위면적 $100m^2$)를 설치하여 조사를 실시하였다. Classification 분석 중 TWINSPAN기법을 이용하여 군락을 분리한 결과, 상수리나무군락(I), 졸참나무-개서어나무군락(II), 소나무-신갈나무군락(III), 굴참나무군락(IV), 리기다소나무-굴참나무-소나무군락(V), 편백림(VI)으로 구분되었다. 군락 I, II는 낙엽성 참나무류가 서로 경쟁하거나 개서어나무 등과 경쟁하여 향후 낙엽활엽수림으로의 천이가 예측되며, 군락 III, V는 소나무와 리기다소나무 등이 낙엽성 참나무류와 경쟁하여 향후 낙엽성 참나무류로의 천이가 예상된다. 군락 IV는 굴참나무가 우점하나 아교목층에서 난온대 수종인 후박나무가 높은 비율로 출현해 점차 후박나무의 세력 확장이 예측된다. 군락 VI은 편백 조림지로 수관층에 편백만이 우점하여 당분간 편백림이 유지될 것으로 예상된다. 이 편백림은 국립공원의 편입취지에 맞게 편백을 간벌하여 천연림으로 갱신을 유도해야 할 것이다. 난온대 기후대에 속하는 팔영산지구에서 출현한 난온대수종은 후박나무, 사스레피나무, 보리밥나무 등 총 9종이었다.

• 한국환경복원기술학회지
• /
• 제24권1호
• /
• pp.1-14
• /
• 2021

The Ministry of Environment of Korea has been releasing Asiatic black bears since 2004 at Jirisan National Park. It exceeded the target number of Asiatic black bears in 2018. As of July 2020, in addition to 67 traceable bears, many Asiatic black bears are dispersed outside Jirisan National Park. Jirisan National Park is a very dense place with more than 3 million visitors every year. In this study, the roads and trails through Jirisan National Park were considered to be the main dispersion factors of Asiatic black bears, and the fragmentation analysis was conducted. As of July 2017, the length of roads and trails in Jirisan National Park was 363.4km. Based on this, Jirisan National Park was fragmented into 163 patches. There is only one place that maintains a single area of more than 50㎢ that is suitable for large mammals to inhabit, and 141 places are less than 5㎢. There are 6 patches of 24 to 200㎢ area suitable for living of large mammals including Asiatic black bears, in Jirisan National Park. Compared to the announcement made by the Korea National Park Service in 2014, activities of Asiatic black bears were rare in areas below 5㎢ area and the frequency of activities was high in more than 20㎢ area. This shows that human activities in protected areas such as national parks can directly affect the activities of wild animals, including Asiatic black bears. Therefore, efforts should be made to improve the habitat of Asiatic black bears by reducing the pressure of visiting for Jirisan National Park. In addition, as a result of analyzing the fragmentation of the park's natural conservation zone 107.7km, 45% of the trail of Jirisan National Park, was opened, which is more fragmentation than other use zones. The park nature conservation zone accounts for about 32% of the total area of Jirisan National Park, but the average patch area is only 2.93㎢ and seven large shelters are located. Therefore the Asiatic black bears are negatively affected. This is the result of inconsistent national park use zone setting and actual park management. In overseas countries, research is active on the negative effects of human activity on ecosystems in protected areas. However, there is a lack of research of that in Korea. Thus, that research is required for protection area management in the future.

• 대한소아치과학회지
• /
• 제30권1호
• /
• pp.124-131
• /
• 2003

최근 치과영역에서 아산화질소(Nitrous Oxide)를 이용한 의식하 진정과 필은 진정의 임상 적용이 증가함에 따라 수술실 또는 진료실 환경이 아산화질소로 오염될 수 있다. 비록 낮은 농도일지라도 장기간 아산화질소에 노출 시 자연유산의 증가, 기형아 출산 증가, 말초신경염 및 운동신경 장애 등과 같은 부작용을 초래하는 것으로 알려져 있다. 호흡시 흡입 공기의 구성성분의 변화를 줄 수 있는 구강 입구로부터 반경 12 inch 이내 영역인 호흡대역(Breathing zone)에서 아산화질소 농도는 치료자에게 영향을 주게된다. 소아 환자에게 주로 적용되는 깊은 진정시는 환자의 구호흡양에 따라서 호흡대역에서 아산화질소의 농도에 영향을 주게되므로, 깊은 진정시 구호흡의 증가 원인을 규명하기 위해 잉여가스 배출 방법을 달리하여 호흡대역에서 아산화질소 농도를 측정 비교하여 다음과 같은 결론을 얻었다. 1. 깊은 진정을 시행하는 경우 호흡대역에서 아산화질소의 농도는 공급 가스량 증가에 의한 비기도 저항 증가에 따라 증가하는 양상을 보였다. 호흡대역에서 아산화질소 농도 증가는 구호흡 증가에 의한 것이며 구호흡은 비기도 저항과 관계가 있다 할 수 있다. 즉 비기도 저항 증가는 구호흡의 한 요인이라 할 수 있다. 음압을 사용한 호기가스 배출장치를 사용하여도 NIOSH에서 권장하는 허용치에는 미치지 못하였고 이를 위해서는 팬이나 다른 제거 장치가 함께 사용되어야 한다. 2. 구강편도의 크기는 기도 저항이 적은 경우 즉 음압을 사용하여 호기가스 제거하는 경우 구호흡에 영향을 주었다.

• 대한공간정보학회지
• /
• 제17권4호
• /
• pp.13-22
• /
• 2009

도시확장은 난개발, 환경, 교통 및 부동산 문제 등을 발생시켰다. 도시확장 패턴분석은 도시확장으로 발생된 문제 해결과 국토관리, 도시계획과 토지이용 분석 및 예측을 위해 필요하다. 본 연구는 환경부에서 제작된 1980년대, 2000년대 토지피복도, 1: 25,000 지형도를 이용한 DEM, 통계청의 인구자료와 대한민국 면적 1ha 이상 도시지역을 추출 후 광역자치단체별로 도시확장 패턴을 GIS, 통계적 기법을 이용해 공간구조 및 패턴분석을 실시하였다. 그 결과, 경기, 인천, 울산은 인구 증가율이 높고, 전남이 낮으며 개발지역 면적은 2.51배 확장 하였다. 경사향은 남향 혹은 동향으로 도시확장은 충남, 경기, 전남 등 지방권에서 주로 증가하였다. 도로 접근성은 기존 도시지역(1980년대 이전 도시 및 건조지역)이 개발지역(1980년대 이후 도시 및 건조지역)보다 높았다. 즉, 도시확장은 각종규제와 정책에 의해 대도시급(특별시, 광역시)에서 지방급(도, 특별자치도)으로, 지형적 조건은 개발에 유리한곳에서 불리한 지역으로 개발됨을 알 수 있었다. 또한 도시확장은 개발지역을 중심으로 인구가 급속히 증가됨을 확인하였다.