• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.601-607
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• 1997

This study was designed to investigate the biochemical pollutant marker for diagnosis of marine pollutions by the changes in lipid components of the flounder (Pleuronichthys cornutus) in the Yellow Sea of Korea. Hemoglobin levels in serum of wild flounders in the yellow Sea were significantly lower $(15\~30\%)$ than those of wild flounder in Pohang (control) of the East Sea. Triglyceride (TG) contents in serum of wild flounders in the Yellow Sea were higher $(15\~50\%)$ than those of wild flounder in Pohang. Total and low density lipoprotein (LDL)-cholesterol contents in serum of flounders in the Yellow Sea were significantly higher $(20\~25\%\;and\;15\~35\%,\;respectively)$ than those of wild flounder in Pohang. Atherogenic index (Al) in serum of wild flounders in the Yellow Sea were significantly higher $(10\~60\%)$ than these of wild flounder in Pohang but T-Chol/PL ratios showed almost no change in serum of flounders in the Yellow Sea we examined. These results suggest that near-coastal water as well as neritic water of the Yellow Sea might be affected by pollutant input.

• The Journal of Engineering Geology
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• v.17 no.1 s.50
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• pp.125-133
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• 2007

The environmental and geotechnical properties are investigated to the 8th landfill area made of only sewage sludge in Nanji-Do. To do this, the soils are sampled in this area, and leaching tests, heavy metal content tests, and so on are performed to research the environmental properties. As the result of heavy metal content tests, Pb, Zn, Cu, Ni, Cd and Cr were leached from the sewage sludge. Because the leaching concentration of Cu is more than the standard value of California state, Cu content have to bring down during the recycling of the sewage sludge. Meanwhile, a series of tests concerning specific gravity, liquid and plastic limits, compaction, permeability and shear strength is performed to research the geotechnical properties. The sewage sludge is consisted of sand, silt and clay, and is classified into non-organic silt or organic clay with 42.3% of plastic index. As the result of compaction test, it is expected that the compaction effect according to variation of water contents is low relatively because the dry unit weight is low and the curve of compaction forms flatness. Also, as the result of direct shear tests, the cohesion is $0.058kg/cm^2$, and the internal friction angle is $14^{\circ}$. Taking everything into consideration, the various problems are happening in case of recycling the sludge like the cover layer of landfill and so on because the compaction is bad, and the shear strength is low. Also, it is expected that the ground water pollution caused by leaching the heavy metal into the sludge. To do recycling the sewage sludge in this site, supplementary and treatment programs should be prepared.

• Korean Journal of Ecology and Environment
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• v.36 no.1 s.102
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• pp.48-56
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• 2003

This study was evaluated about the seasonal variations of ecosystem in Nammae Reservoir based on the interrelation of physico-chemical characteristics, nutrients, chlorophyll a, b, c and standing crops of phytoplanktons. The amounts of chlorophyll a, b, c were respectively maximum (295 mg/, 9.5mg/l and 48mg/l) at station 1 in June and the standing crop of phytoplanktons was the highest ($1.7{\time}10^5$ cells/1) at stations 3 in July. The range of temperature was $7{\sim}37.4^{\circ}C$. The maxium of pH was $9.9{\sim}10.1$ at all stations in August, the minimum was 7 in September. SS was maximum (308 mg/1) at station 1 in June, while it was minimum (4 mg/l) at the same station in November. The maximal COD and DOC were 33 mg/1 and 16 mg/1 respectively at station 1 in June. As for phytoplanktons, Microcystis aeruginosa, blue-green alga in July${\sim}$August, Scenedesmus acutus, green alga in March${\sim}$May and November${\sim}$January and Cyclotella orientalis, Diatoms in October were dominant species. The amounts of P and Si were generally high in summer, they were low in autumn and winter. Nammae Reservoir assessed by trophic state index was eutrophicated and overtrophicated. These results indicated that Nammae Reservoir was faced with heavy water pollution. As preceding management for the basin of the Reservoir, it will have to be continually studied for an ecosystem reservation.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.571-581
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• 2007

The mechanism of water pollution in Lake Shihwa, one of highly eutrophicated artificial lakes in Korea, has been studied using a numerical 3D physical-biochemical coupled model. In this study, the model was applied to estimate the contribution of land-based pollutant load to water quality of heavily polluted Lake Shihwa. The chemical oxygen demand(COD) was adopted as an index of the lake water quality, and the spatial distribution of an average COD concentration during the summer from 1999 to 2000 was simulated by the model. The simulated COD showed a good agreement with the observed data. According to reproducibility of COD, the high-est levels between 8 and 9 mg/L were shown at the inner site of the lake with inflow of many rivers and ditches, while the lowest was found to be about 5 mg/L at the southwestern site near to dike gate. In the pre-diction of water quality of Lake Shihwa, COD showed still higher levels than 3 mg/L in case of reduction of 95% for land-based pollutant load. This suggests that the curtailment of land-based pollutant load is not only sufficient but the improvement of sediment quality or the increase of seawater exchange should be considered together to improve a water quality in Lake Shihwa.

• Economic and Environmental Geology
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• v.38 no.2 s.171
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• pp.101-111
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• 2005

The objectives of this study we to assess the extent and degree of environmental contamination and to draw general conclusions on the fate of toxic elements derived from mining activities in Korea. 인t abandoned mines with four base-metal mines and four Au-Ag mines were selected and the results of environmental surveys in those areas were discussed. In the base-metal mining areas, the Sambo Pb-Zn-barite, the Shinyemi Pb-Zn-Fe, the Geodo Cu-Fe and the Shiheung Cu-Pb-Zn mine, significant levels of Cd, Cu, Pb and Zn were found in mine dump soils developed over mine waste materials, tailings and slag. Furthermore, agricultural soils, stream sediments and stream water near the mines were severely contaminated by the metals mainly due to the continuing dispersion downstream and downslope from the sites, which was controlled by the feature of geography, prevailing wind directions and the distance from the mine. In e Au-Ag mining areas, the Kubong, the Samkwang, the Keumwang and the Kilkok mines, elevated levels of As, Cd, Cu, Pb and Zn were found in tailings and mine dump soils. These levels may have caused increased concentrations of those elements in stream sediments and waters due to direct dis-charge downstream from tailings and mine dumps. In the Au-Ag mines, As would be the most characteristic contaminant in the nearby environment. Arsenic and heavy metals were found to be mainly associated with sulfide gangue minerals, and mobility of these metals would be enhanced by the effect of oxidation. According to sequential extraction of metals in soils, most heavy metals were identified as non-residual chemical forms, and those are very susceptible to the change of ambient conditions of a nearby environment. As application of pollution index (PI), giving data on multi-element contamination in soils, over 1.0 value of the PI was found in soils sampled at and around the mining areas.

• Korean journal of applied entomology
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• v.46 no.3
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• pp.363-373
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• 2007

To evaluate environment of farm lands using indicator insects and evaluation indices, the insect abundance of which is one of the major criteria for the evaluation of agricultural environment of farm land in urban areas and industrial complex, three sites (Ansan, Daesan, Suncheon) were designated and monitored from 2004 to 2006. The flora of agricultural land was more than urban areas and industrial complex of that in three sites. Soil, water and air pollution of urban areas and industrial complex were more serious than those of agricultural land in three sites. Overall population of insects were high from June to August in the surveyed three sites. Collected insects in agricultural land were 12 order, 106 family and 166 species, those in urban areas were 11 order, 102 family and 148 species, and in industrial complex were 11 order, 100 family and 152 species. Species and population belonging to Coleoptera was dominant in the surveyed sites. The insect diversity indices of farm land were 2.36 in agricultural land, 1.92 urban areas and industrial complex. And agricultural environment of agricultural land was good, urban areas was common and industrial complex was poor. Based on the major criteria of evaluation items, the criteria were selected as diversity index over 2.1, insect indicator Pheropsophus javanus in agricultural land, diversity index 1.5-2.0, insect indicator Nephotettix cincticeps in urban areas, diversity index below 1.5, insect indicator Pagria signata in industrial complex.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.655-667
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• 2023

Algal bloom outbreaks are frequently reported around the world, and serious water pollution problems arise every year in Korea. It is necessary to protect the aquatic ecosystem through continuous management and rapid response. Many studies using satellite images are being conducted to estimate the concentration of chlorophyll-a (Chl-a), an indicator of algal bloom occurrence. However, machine learning models have recently been used because it is difficult to accurately calculate Chl-a due to the spectral characteristics and atmospheric correction errors that change depending on the water system. It is necessary to consider the factors affecting algal bloom as well as the satellite spectral index. Therefore, this study constructed a dataset by considering water quality, hydrological and meteorological factors, and sentinel-2 images in combination. Representative ensemble models random forest and extreme gradient boosting (XGBoost) were used to predict the concentration of Chl-a in eight weirs located on the Nakdong river over the past five years. R-squared score (R²), root mean square errors (RMSE), and mean absolute errors (MAE) were used as model evaluation indicators, and it was confirmed that R² of XGBoost was 0.80, RMSE was 6.612, and MAE was 4.457. Shapley additive expansion analysis showed that water quality factors, suspended solids, biochemical oxygen demand, dissolved oxygen, and the band ratio using red edge bands were of high importance in both models. Various input data were confirmed to help improve model performance, and it seems that it can be applied to domestic and international algal bloom detection.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.903-916
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• 2021

An area's topography refers to the shape of the earth's surface, described by its elevation, slope, and aspect, among other features. The topographical conditions determine energy flowsthat move water and energy from higher to lower elevations, such as how much solar energy will be received and how much wind or rain will affect it. Another common factor, the topographic wetness index (TWI), is a calculation in digital elevation models of the tendency to accumulate water per slope and unit area, and is one of the most widely referenced hydrologic topographic factors, which helps explain the location of forest vegetation. Analyses of topographical factors can be calculated using a geographic information system (GIS) program based on digital elevation model (DEM) data. Recently, a large number of free open source software (FOSS) GIS programs are available and developed for researchers, industries, and governments. FOSS GIS programs provide opportunitiesfor flexible algorithms customized forspecific user needs. The majority of biodiversity in island areas exists at about 20% higher elevations than in land ecosystems, playing an important role in ecological processes and therefore of high ecological value. However, island areas are vulnerable to disturbances and damage, such as through climate change, environmental pollution, development, and human intervention, and lacks systematic investigation due to geographical limitations (e.g. remoteness; difficulty to access). More than 4,000 of Korea's islands are within a few hours of its coast, and 88% are uninhabited, with 52% of them forested. The forest ecosystems of islands have fewer encounters with human interaction than on land, and therefore most of the topographical conditions are formed naturally and affected more directly by weather conditions or the environment. Therefore, the analysis of forest topography in island areas can be done more precisely than on its land counterparts, and therefore has become a major focus of attention in Korea. This study is focused on calculating the performance of different topographical factors using FOSS GIS programs. The test area is the island forests in Korea's south and the DEM of the target area was processed with GRASS GIS and SAGA GIS. The final slopes and TWI maps were produced as comparisons of the differences between topographic factor calculations of each respective FOSS GIS program. Finally, the merits of each FOSS GIS program used to calculate the topographic factors is discussed.

• Korean Journal of Environmental Biology
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• v.26 no.4
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• pp.311-322
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• 2008

The objectives of the study were to analyze chemical water quality and physical habitat characteristics in the urban streams (Miho and Gap streams) along with evaluations of fish community structures and ecosystem health, throughout fish composition and guild analyses during 2006$\sim$2007. Concentrations of BOD and COD averaged 3.5 and 5.7 mg L$^{-1}$, in the urban streams, while TN and TP averaged 5.1 mg L$^{-1}$ and 274 ${\mu}g$ L$^{-1}$, indicating an eutrophic state. Especially, organic pollution and eutrophication were most intense in the downstream reach of both streams. Total number of fish was 34 species in the both streams, and the most abundant species was Zacco platypus (32$\sim$42% of the total). In both streams, the relative abundance of sensitive species was low (23%) and tolerant and omnivores were high (45%, 52%), indicating an typical tolerance and trophic guilds of urban streams in Korea. According to multi-metric models of Stream Ecosystem Health Assessments (SEHA), model values were 19 and 24 in Miho Stream and Gap Stream, respectively. Habitat analysis showed that QHEI (Qulatitative Habitat Evaluation Index) values were 123 and 135 in the two streams, respectively. The minimum values in the SEHA and QHEI were observed in the both downstreams, and this was mainly attributed to chemical pollutions, as shown in the water quality parameters. The model values of SEHA were strongly correlated with conductivity (r=-0.530, p=0.016), BOD (r=-0.578, p< 0.01), COD (r=-0.603, p< 0.01), and nutrients (TN, TP: r>0.40, p<0.05). This model applied in this study seems to be a useful tool, which could reflect the chemical water quality in the urban streams. Overall, this study suggests that consistent ecological monitoring is required in the urban streams for the conservations along with ecological restorations in the degradated downstrems.

• Journal of Wetlands Research
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• v.8 no.2
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• pp.53-64
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• 2006

A study on the restoration process of a stream ecosystem and the water quality renovation technique by removing algae, vegetation and fish monitoring as evaluating the removal of the algae by dietetic characteristics of fishes were performed on Sangdong stream in the B city after stream restoration it to the artificial stream as the cases, restoring urban stream into close-to-nature stream are being increased domestically with the aim of ecological city. As a result, restoration and rehabilitation of the fundamental stream ecosystem was well maintained 4 years later the reclamation at the moment and total 93 diagnosis which were all vascular plant phylum including 44 families, 73 genuses, 79 species and 14 varieties in flora and vegetation community were observed. 3 families, 8 species and 354 populations in total among Fishes were found and Pseudorasbora Parva, Cyprinus Carpic and Carassius Auratus strongly resistant to water pollution were dominantly appeared in order of 50.5% of Pseudorasbora Parva 21.2% of Cyprinus Carpic, 20.9% of Carassius Auratus, 7.1% of Macropodus chinensis and 0.3% of Misqurnus anguillicaudatus according to relative richness index. It turned out to be that Cyprinus Carpic ingests algae over 90% and Carassius Auratus takes it over 30% according to the analysis about the alimentary object of the fishes as a consequences of algae's excrescent from characteristics of the tested experimental stream. It is reported that a Cyprinus Carpic, about 34 cm in length, ingested wet-weight 43.2g algae on the rough analysis toward the sample which makes us recognize how effective a macro community Cyprinus Carpic is for removing algae.As a consequence of this research, the effect of stream ecosystem characteristics and water quality purification could not be expected by aquatic plants and trees which were eliminated at experimental stream. From now on, a close-to-nature stream should be formed of ecological hydraulic and hydrologic engineered modeling from the beginning so that it can perform the water quality purifying function. It is determined that the structure of food chain will be abundantly influenced by the induction of oversized macro community like Cyprinus Carpic because a biomass of a consumer of higher order is increased. It is estimated that the removal algae by fishes is not effective despite in some cases of dietetic characteristics so much more studies should be executed in the future.