• Korean Journal of Ecology and Environment
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• v.39 no.1 s.115
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• pp.73-84
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• 2006

The objective of this study was to analyze long-term temporal trends of water chemistry and spatial heterogeneity for 10 sampling sites of the Yeongsan River watershed using water quality dataset during 1995 to 2004 (obtained from the Ministry of Environment, Korea). The water quality, based on multi-parameters of biological oxygen demand (BOD), chemical oxygen demand (COD), conductivity, dissolved oxygen (Do), total phosphorus (TP), total nitrogen (TN) and total suspended solids (TSS), largely varied depending on the sampling sites, seasons and years. Largest seasonal variabilities in most parameters occurred during the two months of July to August and these were closely associated with large spate of summmer monsoon rain. Conductivity, used as a key indicator for a ionic dilution during rainy season, and nutrients of TN and TP had an inverse function of precipitation (absolute r values> 0.32, P< 0.01, n= 119), whereas BOD and COD had no significant relations(P> 0.05, n= 119) with rainfall. Minimum values in conductivity, TN, and TP were observed during the summer monsoon, indicating an ionic and nutrient dilution of river water by the rainwater. In contrast, major inputs of total suspended solids (TSS) occurred during the period of summer monsoon. BOD values varied with seasons and the values was closely associated (r=0.592: P< 0.01) with COD, while variations of TN were had high correlations (r=0.529 : P< 0.01) with TP. Seasonal fluctuations of DO showed that maximum values were in the cold winter season and minimum values were in the summer seasons, indicating an inverse relation with water temperature. The spatial trend analyses of TP, TN, BOD, COD and TSS, except for conductivity, showed that the values were greater in the mid-river reach than in the headwater and down-river reaches. Conductivity was greater in the down-river sites than any other sites. Overall data of BOD, COD, and nutrients (TN, TP) showed that water quality was worst in the Site 4, compared to those of others sites. This was due to continuous effluents from the wastewater treatment plants within the urban area of Gwangju city. Based on the overall dataset, efficient water quality management is required in the urban area for better water quality.

• Journal of Soil and Groundwater Environment
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• v.10 no.1
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• pp.43-57
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• 2005

Twelve bottom sediments and three cores were collected in Juam reservoir for a study on transportation, which was controlled by particle grain size (2mm-200{\mu}m,\;200-100{\mu}m,\;100-50{\mu}m,\;50-20{\mu}m,\;<20{\mu}m), and vertical distribution of heavy metals. Sediment cores were sliced into 2 to 5 cm intervals to measure heavy metal concentrations in interstitial water and sediments with depth. Pb isotopic compositions of core samples were determined to calculate sedimentation rate. Regardless of sampling sites, levels of heavy metals and trace elements in bottom sediments are nearly constant with mean values of $14.9\;{\mu}g/g\;for\;As,\;0.81{\mu}g/g\;for\;Cd,\;30.7{\mu}g/g\;for\;Cu,\;34.7{\mu}g/g\;for\;Ni,\;63.3{\mu}g/g\;for\;Pb\;and\;87.9{\mu}g/g\;for\;Zn$. In general, Cu, Pb, Zn, Wi, and Cr in fraction of $<20{\mu}m$ exhibit the highest concentration, but content of As is the highest in grain size of $2\;mm-200\;{\mu}m$ and $200-100\;{\mu}m$. Fe and Mn occur as the dissolved compositions of the highest concentrations in interstitial waters and increase in their concentrations toward lower part of cores. On the contrary, concentrations of Zn and Cu show the highest value in the uppermost part in cores, suggesting these elements are released from reductive dissolution of hydroxides and oxidation of organic matters under different redox conditions. The highest accumulations of Cu, Ni, Pb, and Zn contents in the sediment cores are observed at 0-4 cm layers, and concentrations of Cu and Pb are especially high, implying these heavy metals are originated from anthropogenic sources. The apparent sedimentation rate estimated using unsupported $^{210}Pb$ is 0.91 cm $year^{-1}$, corresponding about 10 cm sedimentation in total depth since construction of Juam dam. These results will provide available information for management of bottom sediment in Juam reservoir.

• Journal of Environmental Impact Assessment
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• v.26 no.1
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• pp.27-43
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• 2017

The objectives of the study were to evaluate fish compositions, endangered species, community structure, physical habitat, and general water quality for a preliminary environmental impact assessment of Jeokbyeok River on the road construction between two regions. Total number of species and total number of individuals, based on CPUE, were 23 and 1186, respectively. The endangered species (I, II) as the legal protection species were Pseudopungtungia nigra (79 samples) Gobiobotia brevibarba) (5) Gobiobotia macrocephala (2), indicating a requiring of endangered species conservation. In the meantime, exotic species and ecological disturbing species such as Micropterus salmoides and Lepomis macrochirus, were not present, indicating a well conserved area. According to fish community analysis, values of species diversity index were high (range: 0.788 - 1.030), and the dominance index were low (range: 0.097 - 0.183), indicating that the fish community in this area was maintained well without high dominacne by specific species. Also, fish analysis on tolerance guilds and trophic guilds showed that the proportions of sensitive species were largely exceeded the proportions of the tolerant species, while the proportions of insectivore species were largely exceeded the proportions of the omnivore species. This outcome suggests that the ecosystem was well maintained in terms of tolerance and trophic compositions (food chain). Ecological health, based on the multi-metric fish model of Fish Assessment Integrity (FAI), reflected those fish conditions. In other words, values of FAI model averaged 82.4, which means a "good condition" in the criteria of ecological health by the Minstry of Environment, Korea. In addition, general water quality and physical habitat analyses showed that the system was in good condition. Under these conditions, if the road constructions between the two regions happen in the future, inorganic suspended solids may increase in the waterbody, and this may result in indirect or direct influences on the physical habitats and food chain as well as fish compositions, so the ecological protections and prevention strategy from the soil erosion are required in the system.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.4
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• pp.223-233
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• 2010

Spatio-temporal variations of long-term water qualities (COD, SS, $Chl-{\alpha}$, N-related nutrients (TN, TDN, $NO_3^-$, $NH_4^+$), P-related nutrients (TP, TDP, $PO_4^{3-}$)) at two stations (St. SD, St. GG) in the Geumgang Reservoir were investigated from August 2001 to July 2008. Statistical methods such as t-test, factor analysis, and multi-regression analysis were applied to the water quality data in the reservoir as well as mass balances on TP. From the temporal comparisons of the water qualities between 2002 and 2007, average concentrations of $NH_4^+$, $PO_4^{3-}$, and TDP gradually decreased down by 60%, 24%, 52% in 2007. However, those of TP and $Chl-{\alpha}$ increased to 99% and 423% during the period. From the spatial comparisons between the two stations, St. GG showed higher concentrations for all of the N- and P-related nutrients than in St. SD, while opposite result for the $Chl-{\alpha}$. The factor analysis showed that "the seasonal variations of N- and P-related nutrients" were the two dominant factors occupying 49% of total variances of water qualities. Based on this result, multi-regression analysis executed for the two most influential parameters (TP and $Chl-{\alpha}$) focusing on the seasonal variations of these parameters: SS and $Chl-{\alpha}$ has contributed decisively to the concentrations of TP during the wet and dry season, respectively. On the other hand, COD and TP has been important for the $Chl-{\alpha}$ during the wet and dry season, respectively. From the established mass balances of TP loadings in the Geumgang Reservoir, Other Sources (60%) occupied the greatest contribution and Fluvial Input (38%) and Sediment (1%) during the wet season. However, both Fluvial Water (48%) and Other Sources (47%) supplied comparable amount of inputs and Sediment (5%) showed significantly increased input during the dry seasons. Recently especially during the dry winter seasons, migrating bird's excretion was estimated to contribute up to 8% of total TP input and 21% of Other Sources.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.2
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• pp.69-78
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• 2011

Rice is one of the world's staple foods. Paddy rice fields have unique biophysical characteristics that the rice is grown on flooded soils unlike other crops. Information on the spatial distribution of paddy fields and the timing of irrigation are of importance to determine hydrological balance and efficiency of water resource management. In this paper, we detected the timing of irrigation and spatial distribution of paddy fields using the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the NASA EOS Aqua satellite. The timing of irrigation was detected by the combined use of MODIS-based vegetation index and Land Surface Water Index (LSWI). The detected timing of irrigation showed good agreement with field observations from two flux sites in Korea and Japan. Based on the irrigation detection, a land cover map of paddy fields was generated with subsidiary information on seasonal patterns of MODIS enhanced vegetation index (EVI). When the MODISbased paddy field map was compared with a land cover map from the Ministry of Environment, Korea, it overestimated the regions with large paddies but underestimated those with small and fragmented paddies. Potential reasons for such spatial discrepancies may be attributed to coarse pixel resolution (500 m) of MODIS images, uncertainty in parameterization of threshold values for discarding forest and water pixels, and the application of LSWI threshold value developed for paddy fields in China. Nevertheless, this study showed that an improved utilization of seasonal patterns of MODIS vegetation and water-related indices could be applied in water resource management and enhanced estimation of evapotranspiration from paddy fields.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.2
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• pp.82-94
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• 2014

This study aims to comprehend that Gwanghalluwon for aspects of landscape change in terms of construction garden(樓園). Transformation focused on the spatial structure is divided into four periods based on literature. And reflect of landscape elements in defunct or unattributable records from tale and novel. The results were as follows. First, The beginning of Gwanghanllu pavilion(廣寒樓) was the composition of the Gwangtongnu Pavilion(廣通樓). The pavilion is located amid beautiful scenery such as the close-range view of a small stream, and distant view Jiri Mountain. Analysis of literature shows that Gwanghallu pavilion was in succession to Gwangtongnu Pavilion's landscape. Secondly, Gwanghallu(廣寒樓) pavilion represents the characteristic of the garden since 1582. Built the Samsinsan(三神山), Construct Lake and bridge that represents the galaxy for realization of utopia reflect in Taoist ideology. Thirdly, Gwanghalluwon garden was recovered when from Jeong-yu-jae-ran(丁酉再亂) to the Japanese Ruling Era. It took Gwanghalluwon garden a long while to recover from original form. According to records, Gwanghalluwon garden is still being likened to the landscape of fairyland by inheriting landscape in the previous of Jeong-yu-jae-ran(丁酉再亂). Fourth, By the modern times, Gwanghalluwon Garden has personality of tourist attractions. Until now, the area of the Gwanghalluwon garden has been expended during the processes of three times. Fifth, Aspect of landscape change of Gwanghalluwon is wide-spreading mainly Gwanghallu pavilion. But elements of external expansion in garden by introduced into the facility irrelevant to the authenticity of the garden. Sixth, Comprehension the cultural landscape of the garden are limited by deficient records. But, the main elements in the Gwanghalluwon garden are commonly appeared on imaginary environment within a tale and a novel. In addition, culture of garden at the time was depicted in tale and novel. In this sense, cultural landscape in garden was able to estimate through imaginary environment within novel.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.9
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• pp.495-504
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• 2017

An amphibious scrubbing/suction dredging machine with cylindrical rotating brush, housing, and turbidity barrier was newly-developed to remove both sediments with about 10 cm thickness and periphyton attached on various structures in urban water-circulating systems through the scrubbing, suction, and dredging processes. Based on the field application and long-term monitoring, the increase in both suspended solids (SS) and turbidity of water during the scrubbing, suction, and dredging processes was negligible (p>0.05). In some cases, the turbidity of water initially increased, however, the turbidity was stabilized within 20 minutes from the start of dredging processes. The concentration changes in TN and TP of water were not statistically different (p>0.05) before and after the scrubbing, suction, and dredging processes, indicating that benthic nutrients released from sediments were not significantly diffused, and were not supposed to cause significant water pollution. Also, water treatment facilities along with an amphibious scrubbing/suction dredging machine could be more effective since the removal of contaminant loadings through the scrubbing, suction, and dredging processes was much greater than that through simple coagulation/precipitation processes. Finally, GPS-based realtime tracking and operation program have been developed and applied in various urban water-circulating systems, and development of driver cooperative autonomous driving system is in progress to eliminate the need for manual driving of an amphibious scrubbing/suction dredging machine.

• The Korean Journal of Malacology
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• v.19 no.1
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• pp.53-70
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• 2003

In order to understand freshwater molluscan fauna in Asan area, a survey was conducted on the watersheds of this area during the period of October 1999 to August 2000. For the purpose of easy overlook of the molluscan fauna in Asan area, present survey was undertaken on a total of 101 sampling sites of 4 major watersheds connected along Onyang River, Gokgyo River, Sapgyo Lake, and Asan Lake. The collected freshwater mollusks were analysed based on the environment of their habitats. The freshwater mollusks collected through out the present survey were 27 species, 12 families, 5 orders, and 2 classes. Of these, gastropods were 18 species, 10 families, 3 orders; and bivalves were 9 species, 2 families, and 2 orders. The dominant gastropods in this area were Radix auricularia coreana, Cipangopaludina chinensis malleata, Hippeutis cantori, Physa acuta, Gyraulus convexiusculus and Austropeplea ollula and the dominant bivalves were Anodonta arcaeformis, Anodonta arcaeformis flavotincta, and Anodonta woodiana. Dominant species in rice fields were Fossaria truncatula, Segmentina hemisphaerula and Physa acuta, dominant species in rivers were Radix auricularia coreana, Physa acuta, and Hippeutis cantori. Dominant species in reservoirs were Cipangopaludina chinensis malleata, Radix auricularia coreana, Austropeplea ollula, and Fossaria truncatula. Dominant species collected in lakes were Cipangopaludina chinensis malleata, Hippeutis cantori, Cipangopaludina japonica, and Radix auricularia coreana. Radix auricularia coreana, Cipangopaludina chinensis malleata, and Austropeplea ollula were dominantly inhabiting on the muddy bottoms. Anodonta woodiana, Cipangopaludina japonica, and Corbicula fluminea occurred mainly in the gravel areas. Radix auricularia coreana, Cipangopaludina chinensis malleata, and Hippeutis cantori were dominant in the muddy rock areas. Rock-dominant species were Radix auricularia coreana, Semisulcospira forticosta and Koreanomelania paucicincta. Sand-dominant species were Physa acuta, Radix auricularia coreana, and Hippeutis cantori. Sand gravel-dominant species were Physa acuta, Radix auricularia coreana, and oreanomelania paucicincta. Hippeutis cantori, Cipangopaludina chinensis malleata, and Gyraulus convexiusculus occurred in the sand-muddy areas. Cristaria plicata, appointed as an endangered species from the "Natural Environmental Conservation Law", was collected from 5 sampling sites (site Nos. 45, 47, 48, and 52). For the endangered species found in this survey should be make appropriate protection.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.2
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• pp.220-228
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• 2017

Effects of extraction methods on reducing concentrations of pro-oxidants (total iron and protein) of salmon was determined. For development of the extraction process, the effectiveness of several extraction methods was determined and compared, including heat treatment (60, 80, and $100^{\circ}C$), ion exchange and carboxymethyl (CM)-cellulose column chromatography, and ultrafiltration (UF). Protein, total iron, and anserine contents of salmon extracts were 23.64 mg/mL, $16.20{\mu}g/mL$, and 5.47 mg/mL in non-heated extracts, 7.40 mg/mL, $2.32{\mu}g/mL$, and 5.20 mg/mL in heated extracts at $60^{\circ}C$, 7.64 mg/mL, $1.20{\mu}g/mL$, and 5.21 mg/mL at $80^{\circ}C$, and 7.04 mg/mL, $0.68{\mu}g/mL$, and 4.04 mg/mL at $100^{\circ}C$, respectively. Heating and UF decreased contents of protein and total iron, whereas only UF slightly decreased anserine content. Application of the primary ion exchange method increased the content of anserine up to 16%. Protein and total iron contents by the primary ion exchange method decreased by 70 and 98%, respectively. Secondary ion exchange (CM-cellulose) treatment after primary ion exchange and UF resulted in lower anserine content than the primary ion exchange method. However, the content of impurities (protein, total iron) was lower than in all other salmon extracts. Therefore, primary ion exchange, UF, and secondary ion exchange method were the best extraction processes in this study.

• The Korean Journal of Petroleum Geology
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• v.6 no.1_2 s.7
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• pp.25-36
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• 1998

Organic geochemical analyses were carried out in order to characterize organic matter (OM) in the sediments recovered from Korea/japan Joint Development Zone (JDZ V-1, V-3, VII-1 and VII-2) which is located in the northern end of the East China Sea Shelf Basin. Late Miocene sediments from the JDZ V-1 and V-3 wells generally contain less than $0.5\%$ of total organic carbon (TOC). However, early Miocene and Oligocene sediments show TOC values of $0.6-0.8\%$. Middle to late Miocene sediments are rich in TOC up to $20\%$ from JDZ VII-1 and JDZ VII-2 wells. The reason for this rich TOC might be attributed to the presence of coaly shales. Kerogens in the Tertiary sediments from the JDZ series wells are mainly composed of terrestrially derived woody organic matter. Elemental analyses indicate that OM from these wells can be compared to type III. Low hydrocarbon potential and hydrogen index reflect the type of OM. According to the biomarker analyses, the input of the terrestrial OM is prevalent. Oxidizing condition is also indicated by Pristane/Phytane ratio. Samples from the JDZ V-1 and V-3 wells obtain maturities equivalent to the oil generation zone around total depth, and organic matter below 3600 m from JDZ VII-1 and VII-2 wells reached dry gas generation stage. Oligocene sediments below 3500 m in the JDZ VII-1 and JDZ VII-2 wells may have generated limited amount of hydrocarbons, showing a progressive decrease in hydrogen index with depth, due to thermal degradation with increased burial. Gas shows and finely disseminated gilsonite may indicate the generation and migration of the hydrocarbons.