Korea Environment Institute KEI

Sejong, South Korea

Korea Environment Institute KEI

Sejong, South Korea

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Lee M.J.,Korea Environment Institute KEI | Park I.,University of Seoul | Won J.S.,Yonsei University | Lee S.,Korea Institute of Geoscience and Mineral Resources
Geomatics, Natural Hazards and Risk | Year: 2014

This study evaluated the landslide hazard at Inje, Korea, using a geographic information system (GIS) and rainfall probabilistic data. The locations of landslides were identified in the study area by aerial photograph interpretation and field surveys. Data about rainfall probability, topography, and geology were collected, processed, and compiled in a spatial database using GIS. Then, the probability of landslides in the study area in recurrence interval years in the future was calculated assuming that landslides are triggered by a daily rainfall of 202 mm or a three-day cumulative rainfall of 449 mm. Twelve factors that influence landslide occurrence were chosen from a database of topography, soil, and forest cover. Landslide susceptibilities were analysed and mapped according to these landslide-occurrence factors, employing the frequency ratio method. Of the total landslide locations, 50% were used for hazard analysis and the remaining 50% were used for model validation. Validation results for the daily rainfall of 202 mm and three-day cumulative rainfall of 449 mm for recurrence interval years were from 89.22% to 91.80% and from 89.38% to 93.80%, respectively. This analysis of landslide hazards took rainfall probability into account. Rainfall, including heavy rainfall, is expected to increase in the future. © 2014 © 2014 Taylor & Francis.


Lee M.-J.,Korea Environment Institute KEI | Song W.,Dankook University | Lee S.,Korea Institute of Geoscience and Mineral Resources | Lee S.,Korea University
Sustainability (Switzerland) | Year: 2015

The purpose of this study was to create maps of potentially sustainable leopard cat (Prionailurus bengalensis) habitats for all of South Korea. The leopard cat, which is on the International Union for Conservation of Nature (IUCN) Red List, is the only member of the Felidae family in Korea. To create habitat potential maps, we selected various environmental factors potentially affecting the species' distribution from a spatial database derived from geographic information system (GIS) data: elevation, slope, distance from a forest stand, road, or drainage, timber type, age, and land cover. We analyzed the spatial relationships between the distribution of the leopard cat and the environmental factors using a frequency ratio model and a logistic regression model. We then overlaid these relationships to produce a habitat potential map with a species potential index (SPI) value. Of the total number of known leopard cat locations, we used 50% for mapping and the remaining 50% for model validation. Our models were relatively successful and showed a high level of accuracy during model validation with existing locations (frequency ratio model 82.15%; logistic regression model 81.48%). The maps can be used to manage and monitor the habitat of mammal species and top predators. © 2015 by the authors.


Song W.,Korea Environment Institute KEI | Kim E.,Korea Environment Institute KEI | Lee D.,Seoul National University | Lee D.,Research Institute for Agriculture and Life science | And 2 more authors.
Ecological Modelling | Year: 2013

Species distribution modeling is one of the most effective habitat analysis methods for wildlife conservation. We evaluated the sensitivity of species distribution modeling to different grain sizes and extent sizes from 30m to 4950m using maximum entropy (MaxEnt) modeling. The grain size represents a unit for analysis, whereas the extent size defines the scope of the analysis in a way that reflects the environmental data for the area in which the species of interest occurs. We compared the resulting suitability indexes and habitat areas based on two approaches. The first approach increases the extent size for a fixed grain size. The second approach increases the grain size and the extent size by equal amounts. The suitability index based on the first approach (R2=0.34) was greater than the suitability index based on the second approach (R2=0.89). The first approach was fitted to a logarithmic function with a critical point at approximately 0.5km, converging to about 0.76. In contrast, the second approach showed a linear decrease to values less than 0.5. The distribution of habitat area found with the second method (R2=0.87) was broader than that found with the first method (R2=0.63). The relationship between the extent size and the landscape index of the first method can be displayed as a power-law graph with a critical point of 0.5km. The method of expanding extent size has greater accuracy, although the time that it requires for data processing is long. The results of this study suggest that the maximum grain size should be approximately 1.5km. If the grain size is greater than 1.5km, the accuracy of the habitat suitability index decreases below 0.6, and the predicted habitat suitability increases dramatically. © 2012 Elsevier B.V.


Lee M.J.,Korea Environment Institute KEI | Park I.,University of Seoul | Won J.S.,Yonsei University | Lee S.,Korea Institute of Geoscience and Mineral Resources | Lee S.,Korean University of Science and Technology
Geomatics, Natural Hazards and Risk | Year: 2016

This study evaluated the landslide hazard at Inje, Korea, using a geographic information system (GIS) and rainfall probabilistic data. The locations of landslides were identified in the study area by aerial photograph interpretation and field surveys. Data about rainfall probability, topography, and geology were collected, processed, and compiled in a spatial database using GIS. Then, the probability of landslides in the study area in recurrence interval years in the future was calculated assuming that landslides are triggered by a daily rainfall of 202 mm or a three-day cumulative rainfall of 449 mm. Twelve factors that influence landslide occurrence were chosen from a database of topography, soil, and forest cover. Landslide susceptibilities were analysed and mapped according to these landslide-occurrence factors, employing the frequency ratio method. Of the total landslide locations, 50% were used for hazard analysis and the remaining 50% were used for model validation. Validation results for the daily rainfall of 202 mm and three-day cumulative rainfall of 449 mm for recurrence interval years were from 89.22% to 91.80% and from 89.38% to 93.80%, respectively. This analysis of landslide hazards took rainfall probability into account. Rainfall, including heavy rainfall, is expected to increase in the future. © 2014 Taylor & Francis.


Lee E.,Seoul National University | Hyun Y.,Korea Environment Institute KEI | Lee K.,Seoul National University | Shin J.,Seoul National University
Hydrogeology Journal | Year: 2012

A radial collector well is used for the extraction of a large amount of groundwater without causing a deep drawdown at the well's center, and it is appropriate for the supply of municipal water through riverbank filtration (RBF). Flow path changes caused by water extraction through a radial collector well were simulated to estimate the amount of river water induction at a RBF site associated with Nakdong River in South Korea. The structure of the screened horizontal arms of a radial collector well was examined with respect to effective riverbank filtration. The relative ratio of the river water induced to the radial collector well compared to the total groundwater extraction was estimated to be 27-52%. The amount of induced river water varies with the distance of a horizontal arm from the river, indicating that the location and structure of the collector well is significant for RBF. In all simulation cases, the maximum drawdown of the groundwater level near the collector well was 2. 1 m, which is not significant considering the substantial pumping rate at the study site. It was concluded that RBF radial collector wells can be used at the study site for a sustainable water supply. © 2011 Springer-Verlag.


Park J.C.,Miryang Regional Office | Song Y.-I.,Korea Environment Institute KEI | Jung Y.M.,K water | Song S.J.,K water | Park D.,Konkuk University
International Journal of Water Resources Development | Year: 2014

This study compares the benefits and disadvantages of two options, i.e. dam construction and a water transfer tunnel between two existing dams, with a particular focus on their effects on the natural environment and local communities and their respective economic efficiencies. It is concluded that significant advantages exist for the construction of a water transfer tunnel between two dams in Korea. This option would secure water resources in a manner that minimizes the economic, environmental and social effects of water resource development and which maximizes the utility of existing water resources. © 2014 Taylor & Francis


Kim Y.,University of Alaska Fairbanks | Kodama Y.,Japan National Institute of Polar Research | Shim C.,Korea Environment Institute KEI | Kushida K.,Nihon University
Polar Science | Year: 2014

The Boreal black spruce forest is highly susceptible to wildfire, and postfire changes in soil temperature and substrates have the potential to shift large areas of such an ecosystem from a net sink to a net source of carbon. In this paper, we examine CO2 exchange rates (e.g., NPP and Re) in juniper haircap moss (Polytrichum juniperinum) and microbial respiration in no-vegetation conditions using an automated chamber system in a five-year burned black spruce forest in interior Alaska during the fall season of 2009. Mean ± standard deviation microbial respiration and NEP (net ecosystem productivity) of juniper haircap moss were 0.27 ± 0.13 and 0.28 ± 0.38 gCO2/m2/hr, respectively. CO2 exchange rates and microbial respiration showed temporal variations following fluctuation in air temperature during the fall season, suggesting the temperature sensitivity of juniper haircap moss and soil microbes after fire. During the 45-day fall period, mean NEP of P. juniperinum moss was 0.49 ± 0.28 MgC/ha following the five-year-old forest fire. On the other hand, simulated microbial respiration normalized to a 10 °C temperature might be stimulated by as much as 0.40 ± 0.23 MgC/ha. These findings demonstrate that the fire-pioneer species juniper haircap moss is a net C sink in the burned black spruce forest of interior Alaska. © 2014 Elsevier B.V.


Ha J.H.,Korea Environment Institute KEI | Hidaka T.,Kyoto University | Tsuno H.,Kyoto University
Environmental Toxicology | Year: 2011

Chlorophyll-a concentration has been used as an indicator to estimate microcystin levels in water bodies. This study examined the microcystin to chlorophyll-a ratio in a fishpond in Japan. The ratio varied spatially and temporally during the six-month field survey, which is consistent with reports by other researchers. We investigated the causes of the variability of the ratio by quantifying microcystin synthetase (mcy) A gene with real-time PCR, so as to observe the growth of microcystin-producing cyanobacteria and Microcystis strains in natural cyanobacterial blooms. The application of real-time PCR enabled corroboration of the relationship between the toxigenicity and the toxicity of the blooms. The microcystin to chlorophyll-a ratio was influenced by the combined effects of the durability of the toxic bloom, and the quantity of microcystin-producing cyanobacteria carrying the mcy A gene, especially toxic Microcystis strains. Cyanobacterial blooms produced more microcystin when high concentrations of microcystin-producing Microcystis aggregated in a stationary state with low growth rates. The variable toxicity of blooms needs to be reflected in accurate and efficient alert systems for toxic cyanobacteria and cyanotoxins. © 2009 Wiley Periodicals, Inc.


Kim M.-H.,Hanyang University | Park T.-J.,Korea Environment Institute KEI | Kim M.,Hanyang University
Environmental Technology (United Kingdom) | Year: 2013

Microbial characteristics of a fixed-biofilm process packed with hollow-type ceramic media were studied for treating low organic level sewage (average ratio=3.4), and an easy monitoring method such as a bio-index was suggested. The fractions of autotrophs and heterotrophs were directly affected by changing the organic surface loads in the aerobic reactors. After 90 days of operation, the amount of attached biomass was maintained constantly with a stable nitrification rate and low effluent concentration. At this point, the dominant diatoms observed were Fragilaria sp. in the second anoxic reactor, Cyclotella sp. in the second anoxic and aerobic reactors, and Navicula sp. in the first aerobic reactor. Specific protozoa (Euglypha sp., Arcella sp. and Colepus sp.), which were considered predators of nitrifiers, were observed under high nitrification rate and were used as a bio-index and indicators of nitrifying biofilm formation and low effluent concentration in the fixed-biofilm BNR process. © 2013 Copyright Taylor and Francis Group, LLC.


Kim H.,Korea Environment Institute KEI | Hong H.-J.,Korea Advanced Institute of Science and Technology | Jung J.,Korea Advanced Institute of Science and Technology | Kim S.-H.,Korea Advanced Institute of Science and Technology | Yang J.-W.,Korea Advanced Institute of Science and Technology
Journal of Hazardous Materials | Year: 2010

Nowadays, many researchers have studied the environmental application of the nanoscale zero-valent iron (nZVI) and several field applications for the groundwater remediation have been reported. Still, there are many concerns on the fate and transport of the nZVI and the corresponding risks. To avoid such concerns, it was investigated to immobilize nZVI in a support and then it was applied to degrade trichloroethylene (TCE). The nZVI and palladium-doped nZVI (Fe(0)- and Fe/Pd-alginate) were immobilized in the alginate bead where ferric and barium ions are used as the cross-linking cations of the bead. According to TEM (transmission electron microscopy), the size of the immobilized ZVI was as small as a few nanometers. From the surface analysis of the Fe/Pd-alginate, it is found that the immobilized nZVI has the core-shell structure. The core is composed of single crystal Fe0, while most of irons on the surface are oxidized to Fe3+. When 50 g/L of Fe/Pd-alginate (3.7 g Fe/L) was introduced to the aqueous solution, >99.8% of TCE was removed and the release of metal from the support was <3% of the loaded iron. The removal of TCE by Fe/Pd-alginate followed pseudo-first-order kinetics. The observed pseudo-first-order reaction constant (kobs) of Fe/Pd-alginate was 6.11 h-1 and the mass normalized rate constant (km) was 1.6 L h-1 g-1. The km is the same order of magnitude with that of iron nanoparticles. In conclusion, it is considered that Fe/Pd-alginate can be used efficiently in the treatment of chlorinated solvent. © 2009 Elsevier B.V. All rights reserved.

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