• Journal of Korean Society of Rural Planning
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• v.2 no.1
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• pp.69-78
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• 1996

Environmental impact assessment survey reflecting farmers` opinion on the residence and production space in rural settlement area by ORD showed that more than 86% of respondents thought their reservoirs and waterways (small rivers) were getting seriously contaminated primarily by garbage and livestock manure. A typical rural settlement unit was taken to assess the impact of improper management of livestock manure in the farms on the water quality of small river flowing down along the villages where swine and dairy farms were situated in Daejook 2, 3-ri, Seolseong-myun, Icheon-gun. Nitrogen compounds such as NO$_3$-N, NO$_2$-N, NH$_3$-N, and phosphorus compound H$_x$PO$_4$, DO, BOD$_5$, COD, and microbial density were analyzed to evaluate water quality at five test sites designated along the water stream. Tests showed. for example, BOD$_5$ at site 4 was average 9.2mg/l which was about 3~8 times higher than that of observation site 2 and 3, at which most livestock houses were situated. This is a clear evidence that the nutrients of livestock manure illegally discharged to small river can lead to an eutrophication of the river at downstream. A soil absorption system with aeration could be one of alternatives to treat the contaminated wastewater by livestock manure. The place at downstream, inbetween observation site 1 and 2, could be the best construction site for the treatment facility from the standpoint of the overall treatment efficiency, An enclosed composting system can also be regarded as a good alternative for treatment of the sludge which is the by-product of the soil absorption system operation.

• Ocean and Polar Research
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• v.29 no.4
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• pp.327-337
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• 2007

Plankton communities have close relationships with environmental changes in water columns. Thus, the use of plankton as a biological tool for assessing the marine ecosystem health may be effective. Major issue regarding coastal pollution has been usually recognized as phytoplankton blooms or red tides caused by the eutrophication, an increase in concentration of inorganic nutrients such as nitrogen and phosphorus. However, in order to understand the effects of the overall pollution on marine ecosystem, the organic pollutants as well as the inorganic nutrients should be also considered. For understanding the effects of the organic pollution, among the planktonic organisms, heterotrophic bacteria, heterotrophic flagellates and ciliates should be investigated. Generally, there are three approaches for assessing the marine ecosystem health using the plankton taxa or plankton communities. The first one is a community-based approach such as diversity index and chlorophyll a concentration which are common in analysis of the plankton communities. The second is an indiviual-based approach which is to monitor the pollution indicative species. This approach needs one's ability to identify the plankton to species level. The last approach is a bioassay of toxicity, which can be applied to the plankton. A pilot study in Masan Bay was conducted to assess the effects of the inorganic and organic pollution. In this article, a new approach using plankton communities was tentatively presented as a biological tool for assessing the ecosystem health of Masan Bay.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.1
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• pp.1-11
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• 2010

Generation and transportation of runoff and pollutant loads within watershed generated eutrophication at Daecheong reservoir. To improve water quality at Daecheong reservoir, the best management practices should be developed and applied at upper watersheds for water quality improvement at downstream areas. In this study, two small watersheds of upper Daecheong reservoir were selected. The Long-Term Hydrologic Impact Assessment (L-THIA) model has been widely used for the estimation of the direct runoff worldwide. To apply the L-THIA ArcView GIS model was evaluated for direct runoff and water quality estimation at small watershed. And the Web-based Hydrograph Analysis Tool (WHAT) was used for direct runoff separating from total flow. As a result, the $R^2$ (Coefficient of determination) value and Nash-Sutcliffe coefficient value for direct runoff comparison at An-nae watershed were 0.81 and 0.71, respectively. And the $R^2$ value and Nash-Sutcliffe coefficient value at Wol-oe were 0.95 and 0.93. The $R^2$ value of BOD, TOC, T-N and T-P at An-nae watershed were BOD 0.94, TOC 0.81, T-N 0.94 and T-P 0.89. And the $R^2$ value of BOD, TOC, T-N and T-P at Wol-oe watershed were BOD 0.80, TOC 0.93, T-N 0.86 and T-P 0.65. The result that estimated pollutant loadings using the L-THIA ArcView GIS model reflected well the measured pollutant loadings except for T-P in Wol-oe watershed. With L-THIA ArcView GIS model, the direct runoff and non-point pollutant (NPS) loadings in the watershed could be analyzed through simple input data such as daily rainfall, land uses, and hydrologic soil group.

• Journal of Ecology and Environment
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• v.43 no.1
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• pp.22-30
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• 2019

Background: Piton du Milieu (PdM) impounding reservoir is suspected to be eutrophic based on the elevated level of orthophosphate and nitrate. Water supplies from three adjacent rivers are primarily thought to contribute to the nutrient enrichment of the reservoir. It is also suspected that there is leaching of orthophosphate, nitrate and organic matter into the rivers during rainfall events and also as a result of anthropogenic activities within the catchment area. The aim of this study was to ascertain the impact of nutrient loading on the water quality of PdM water and on the population of freshwater microalgae in the reservoir. The enumeration and identification of algae from PdM were performed by differential interference contrast microscopy. Dissolved oxygen (DO) and pH were determined by electrometric methods, whereas nutrient levels, silica and total organic carbon (TOC) were determined by instrumentation techniques. Results: Annual mean orthophosphate, nitrate and total organic carbon input from the three feeders within the catchment area of PdM reached levels as high as 0.09 mg/L, 0.4 mg/L and 2.62 ppm respectively. Over a 12-month period, mean TOC concentration in the reservoir was 2.32 ppm while the mean algal cell count was 4601 cells/mL. The dominant algal species identified were Oscillatoria, Cyclotella, Navicula and Cosmarium. Conclusion: This study highlights the trophic state of the reservoir water and clearly points to the need for constant monitoring in order to avoid the occurrence of an impending harmful algal bloom.

• Journal of Korean Society on Water Environment
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• v.35 no.3
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• pp.271-277
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• 2019

Korean Trophic State Index ($TSI_{KO}$) was developed in 2006, and was composed of COD ($COD_{Mn}$ based on permanganate method), Chlorophyll a (Chl.a) and total phosphorus (TP). However, $COD_{Mn}$ usually represents only 50-60% of total organic matter in stream or lake water due to low oxidizing power of permanganate. This study investigated the relationship between TOC and $COD_{Mn}$ based on the average data for the whole layer in 81 lakes in Korea, during the period 2013-2017. As a result, $COD_{Mn}$ was found to be 1.54 times more than TOC in 66 of the freshwater lakes and 3 brackish lakes (TOC measured using thermo-oxidation method). TOC was about a quarter of $COD_{Mn}$ in 8 coastal lakes (TOC measured using UV-persulfate oxidation method), and it appeared to be underestimated due to chloride interference. Using the data of 69 lakes with exception of 12 brackish lakes, $TSI_{KO}$(TOC) was developed based on the correlation between TOC and $COD_{Mn}$, while $TSI_{KO}$(COD) was replaced with $TSI_{KO}$(TOC). However, for trophic state assessment of brackish lakes, the $TSI_{KO}$(TOC) can only be utilized in case that TOC is measured through thermo-oxidation method. The determination coefficient of $TSI_{KO}$(Chl) to $TSI_{KO}$(COD) in 66 freshwater lakes and 3 brackish lakes was 0.83, while that to $TSI_{KO}$(TOC) was 0.68. This difference could be attributed to the recalcitrant organic part of TOC.

• Resources Recycling
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• v.32 no.2
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• pp.43-51
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• 2023

In this research, through LCA analysis, the environmental impact of automotive engine manufacturing and re-manufacturing was analyzed from the perspective of the entire process, and the greenhouse gas reduction effect was calculated based on this. The amount of greenhouse gas emitted from the process of acquiring and manufacturing raw materials for automotive engines is about 3,473 kg for new manufacturing and 872 kg for re-manufacturing. Thus, the amount of greenhouse gas reduction by engaging in re-manufacturing is about 2,601 kg; the analysis shows a reduction effect in each part of the entire process except for the processing stage. As a result of the LCA weighted analysis, the environmental impact of new product manufacturing was found to be 1.07E+03 Eco-point, and it was 2.67E+02 Eco-point for re-manufacturing. The share of GWP(Global Warming Potential) among the six major impact categories(Abiotic Depletion Potential, Acidification Potential, Eutrophication Potential, Global Warming Potential, Ozone-layer Depletion Potential, Photochemical Oxidant Creation Potential) as high at 99.72%(new manufacturing) and 99.68%(re-manufacturing).

• Journal of Environmental Impact Assessment
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• v.28 no.6
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• pp.549-555
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• 2019

The purpose of this study is to ensure optimal operating conditions for improving the removal efficiency of phosphorus (P) and nitrogen (N) that are the causative agents of eutrophication by utilizing functional media. The main ingredients of the functional media used in this study are Si, Al, and Fe, SiO₂, KAlSiO₃O₈, Al₂O₂·2SiO₂O, H₃Al₂Si₂O₉, Fe₃O₄O), and berylite. To identify the maximum efficiency of the filtration process, the processing efficiency experiment was carried out according to flow method, velocity, and thickness of residual media. The flow method carried out two experiments, 50 m/day, 100 m/day, 150 m/day, 200 m/day, 250 m/day, and 20 cm, 40 cm, 50 cm, 60 cm, 80 cm of lead depth. Experiments have shown that SS, T-N, and T-P all showed higher elimination efficiency of the upflow current conditions than the downflow current conditions, and that the processing efficiency of the linearity is the highest at SS 50 m/day, T-N 150 m/day and T-P 100 m/day. In addition, the analysis of the removal efficiency according to the residual thickness showed that SS, T-N, and T-P all showed the highest efficiency at 60 cm. In addition, the analysis of the removal efficiency according to the residual thickness showed that SS, T-N, and T-P all showed the highest efficiency at 60 cm. It is considered desirable to set the top-down flow conditions and residual thickness of 60 cm and adjust the velocity of the line according to the target media for removal.

• Korean Journal of Ecology and Environment
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• v.43 no.3
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• pp.356-368
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• 2010

In this study, we applied approach of integrative star-plot area (SPA), chemical water quality and habitat conditions (QHEI) to diagnoze ecological conditions at the eight sampling sites of Sapkyo Stream. These outcomes were compared with biological health based on the Index of Biological Integrity (IBI) using fish assemblage. And then, we evaluated the integrative ecological health condition using the star-plot method. This approach based on the sum of all the star-plot areas over these water and habitat characteristics. It was developed to reflect an integrative assessment of the ecological health in the stream. The biological health, based on the model values of IBI indicating "fair-poor" condition according to the criteria. Physical habitat health, based on the QHEI, averaged 123 indicating a "good-fair" condition. Also, chemical health, based on simply BOD values indicating "poor grade" according to the criteria of the Ministry of Environment Korea (MEK). The SPA indicating that 50% of the all was impaired condition and the most sampling sites were downstream sites influenced by the point and non-point sources. Overall our results suggest that the ecological health impact was a combined effect of eutrophication and habitat degradations in the stream. The approach of SPA can be used as a tool to evaluate the integrative health of stream environment and to identify possible causes of observed effects.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.1
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• pp.16-23
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• 2003

Soil and water quality was monitored in the Nakdong River basin to assess the impact of different agricultural practices. From five catchments, soil samples were collected at three times during 1996 to 1998, and water samples were collected at twelve times on July during 1995 to 1999. The major agricultural practices were paddy and upland farming in three areas surveyed: Youngju, Goryung, and Milyang. Apple orchards were located along in the Imgo-Cheon catchment. Intensive vegetable farming in plastic fIlm house was practiced in the Habin-Cheon catchment. Total N contents, 0.04-0.32%, of paddy soils were low in comparison with those of upland, orchard, and plastic film house soils. Available phosphate($P_2O_5$) contents, $2-421mg\;kg^{-1}$, in plastic film house soils were higher than those in paddy soils. In plastic film house and upland soils, CEC of soils were high. The N concentrations in most of the streams were higher than $1.0mg^{-1}$, the standard of agricultural irrigation water. The P concentrations were above $1.0mg^{-1}$, the standard of agricultural irrigation water and were higher than the minimum level for eutrophication, $0.01-0.05mg\;L^{-1}$ in most of the streams. In conclusion, nutrients by agricultural activity could affect water quality of streams near the agricultural fields. Good water quality in streams can be maintained by proper management of agricultural fields and by decreasing application amount of fertilizers in agricultural fields.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6943-6951
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• 2014

The trophic state assessment of the Hwoiya reservoir was estimated using the Trophic state indices (TSIs) of Carlson and Aizaki using the transparency and concentrations of chlorophyll-a and total phosphorus obtained from two sites of the reservoir. The TSIs assessments showed that eutrophic phenomena occur frequently in the Hwoiya reservoir. In addition, strategies to reduce the phosphorus especially would be prepared because the Hwoiya reservoir exceeded phosphorus-limiting state of 17 < TN/TP (total nitrogen/total phosphorus). Three scenarios for a simulation of the dredging effect of sediments on the water quality using the WASP7 model were made at two sites, which were 10% (scenario 1), 40% (scenario 2) and 60% elution of the pollutants from sediments (scenario 3). In the most elution case (60%), scenario 3, it was considered that 6.4% TN and 9.3% TP at site 1, and 3.9% TN and 5.6% TP at site 2 could be reduced.