• The Journal of Engineering Geology
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• v.18 no.4
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• pp.471-482
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• 2008

This study was carried out to investigate the contamination characteristics of surface water, soil water and groundwater around and in antimony waste landfill site in Wonsung-ri, Yeonki-kun, Chungnam. The waste disposed in the study was excavated and transported to the other site in several years ago. For this study, we collected 35 water samples including groundwater, soil water and surface in the study site and also collected 2 groundwater samples from a comparison site. The data of chemical analysis of soil water samples show the antimony concentration of $48.75{\sim}74.81\;ppb$, which is much higher than groundwater in a comparison site and is highly excess than regulation level for a drinking water of some advanced countries. A relatively high antimony concentration was detected in three stream water samples nearby landfill site and two groundwater samples. Fe and Mn contents in soil water and stream water were measured as maxium 6.5 mg/L and 7.3 mg/L, respectively. Although other heavy metals of water samples in the study site are higher concentration than water sample of comparison site, their absolute levels are lower than regulation level for a drinking water. The chemical data of water samples are plotted widely from Ca - $HCO_3$ type to Ca - ($Cl +SO_4+NO_3$) type. Some groundwater show high contents of potassium and nitrate, which would come from fertilizer and sewage. Conclusively, some heavy metals including antimony have been still remained under the soil surface of the landfill site in the past. These metals have leaked out into nearby stream and groundwater system, and threaten the ecology, crops and the health of residents in this site. Therefore, the government have to prepare the strategy to prevent the diffusion of heavy metals into aquatic environment and have to process the reclamation work for contaminated site. It is also necessary to make a regulation level of the antimony concentration for a drinking water and soil environment in Korea.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.555-566
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• 2008

Hydrogeochemical study in Samseung area (Boeun, Chungbuk) and waterrock interaction experiment using rock samples from the area were performed to elucidate the fluoride source in groundwater and explaining geochemical behavior of fluoride ion. Fluoride concentration of public water supply mostly using groundwater in Boeun area was significantly higher in South Korea. The maximum fluoride concentration of the study area was 3.9 mg/L, and 23% of samples exceeded the Korean Drinking Water Standard of fluoride (1.5 mg/L). The average concentration of fluoride was 1.0 mg/L and median was 0.5 mg/L. Because of high skewness (1.3), median value is more appropriate to represent fluoride level of this area. The relationships between fluoride ion and geochemical parameters ($Na^+$, $HCO_3$, pH, etc.) indicated that the degree of waterrock interaction was not significant. However, high fluoride samples were observed in $NaHCO_3$ type on Piper's diagram. The negative relationship between fluoride and $NO_3$ ion which might originate from surface contaminants was obvious. These results indicate that fluoride ion in groundwater is geogenic origin. The source of fluoride was proved by waterrock interaction batch test. Fluoride concentration increased up to 1.2 mg/L after 96 hours of reaction between water and biotite granite. However, the relationship between well depth and fluoride ion, and groundwater age and fluoride ion was not clear. This indicates that fluoride ion is not correlated with degree of waterrock interaction in this area but local heterogeneity of fluoriderich minerals in granite terrain. High fluoride concentration in Boeun area seems to be correlated with distribution of permeable structures in hard rocks such as lineaments and faults of this area. This entails that the deep bedrock groundwater discharges through the permeable structures and mixed with shallow groundwater.

• Microbiology and Biotechnology Letters
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• v.3 no.3
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• pp.123-134
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• 1975

Out of 96 yeast strains isolated from various natural habitats, five strains were screened based on their ability to ferment agricultural biproducts such as rice-, barley-and wheat-bran, and sawdust. These were identified as Hansenula anomala var anomala, Candide utilis, C. pelliculosa, Debaryomyces hansenii, and Irpex lacteus. Using these yeasts the above mentioned agricultural biproducts were fermented in various combinations. The fermented product was fed to 180 male Starcroses for eight weeks and obtained a body weight increase of 15.1g a day, while the unfermented control feed increased 10.5g a day.

• Economic and Environmental Geology
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• v.56 no.2
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• pp.139-153
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• 2023

This study aimed to understand the spatiotemporal variations in nitrogen content in the Gyeongan stream along the main stream and at the discharge points of the sub-basins, and to identify the origin of the nitrogen. Field surveys and laboratory analyses, including chemical compositions and isotope ratios of nitrate and boron, were performed from November 2021 to November 2022. Based on the flow duration curve (FDC) derived for the Gyeongan stream, the dry season (mid-December 2021 to mid-June 2022) and wet season (mid-June to early November 2022) were established. In the dry season, most samples had the highest total nitrogen(T-N) concentrations, specifically in January and February, and the concentrations continued to decrease until May and June. However, after the flood season from July to September, the uppermost subbasin points (Group 1: MS-0, OS-0, GS-0) where T-N concentrations continually decreased were separated from the main stream and lower sub-basin points (Group 2: MS-1~8, OS-1, GS-1) where concentrations increased. Along the main stream, the T-N concentration showed an increasing trend from the upper to the lower reaches. However, it was affected by those of the Osan-cheon and Gonjiamcheon, the tributaries that flow into the main stream, resulting in respective increases or decreases in T-N concentration in the main stream. The nitrate and boron isotope ratios indicated that the nitrogen in all samples originated from manure. Mechanisms for nitrogen inflow from manure-related sources to the stream were suggested, including (1) manure from livestock wastes and rainfall runoff, (2) inflow through the discharge of wastewater treatment plants, and (3) inflow through the groundwater discharge (baseflow) of accumulated nitrogen during agricultural activities. Ultimately, water quality management of the Gyeongan stream basin requires pollution source management at the sub-basin level, including its tributaries, from a regional context. To manage the pollution load effectively, it is necessary to separate the hydrological components of the stream discharge and establish a monitoring system to track the flow and water quality of each component.

• Ecology and Resilient Infrastructure
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• v.10 no.3
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• pp.85-96
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• 2023

The study involved the categorization of domestic lakes located in South Korea into three groups based on their salinity levels: upstream reservoirs with salinity less than 0.3 psu, estuarine reservoirs with salinity ranging from 0.3 to 2 psu, and brackish lagoons with salinity exceeding 2 psu. Subsequently, the research assessed variations in the concentrations of total nitrogen (T-N) and total phosphorus (T-P) in the sediment of these lakes using statistical analysis, specifically one-way analysis of variance (ANOVA). Additionally, a laboratory core incubation test was conducted to investigate the benthic nutrient fluxes in Songji lagoon (salinity: 11.80 psu), Ganwol reservoir (salinity: 0.73 psu), and Janggun reservoir (salinity: 0.08 psu) under both aerobic and anoxic conditions. The findings revealed statistically significant differences in the concentrations of T-N and T-P among sediments in the lakes with varying salinity levels (p<0.05). Further post-hoc analysis confirmed significant distinctions in T-N between upstream reservoirs and estuarine reservoirs (p<0.001), as well as between upstream reservoirs and brackish lagoons (p<0.01). For T-P, a significant difference was observed between upstream reservoirs and brackish lagoons (p<0.01). Regarding benthic nutrient fluxes, Ganwol Lake exhibited the highest diffusive flux of NH₄⁺-N, primarily due to its physical characteristics and the inhibition of nitrification resulting from its relatively high salinity. The flux of NO₃^--N was lower at higher salinity levels under aerobic conditions but increased under anoxic conditions, attributed to the impact of salinity on nitrification and denitrification. Additionally, the flux of PO₄^3--P was highest in Songji Lake, followed by Ganwol Lake and Janggun Reservoir, indicating that salinity promotes the diffusive flux of phosphate through anion adsorption competition. It's important to consider the influence of salinity on microbial communities, growth rates, oxidation-reduction processes, and nutrient binding forms when studying benthic diffusive nutrient fluxes from lake sediments.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.1
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• pp.41-50
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• 2010

We have developed an in-situ benthic chamber (BelcI) for use in coastal studies that can be deployed from a small boat. It is expected that BelcI will be useful in studying the benthic boundary layer because of its flexibility. BelcI is divided into three main areas: 1) frame and body chamber, 2) water sampler, and 3) stirring devices, electric controller, and data acquisition technology. To maximize in-situ use, the frame is constructed from two layers that consist of square cells. All electronic parts (motor controller, pA meter, data acquisition, etc.) are low-power consumers so that the external power supply can be safely removed from the system. The hydrodynamics of BelcI, measured by PIV (particle image velocimetry), show a typical "radial-flow impeller" pattern. Mixing time of water in the chamber is about 30 s, and shear velocity ($u^*$) near the bottom layer was calculated at $0.32\;cm\;s^{-1}$. Measurements of diffusivity boundary layer thickness showed a range of $180-230\;{\mu}m$. Sediment oxygen consumption rate, measured in-situ，was $84\;mmol\;O_2\;m^{-2}\;d_{-1}$, more than two times higher than on-board incubation results. Benthic fluxes assessed from in-situ incubation were estimated as follows: nitrate + nitrite = $0.18\;{\pm}\;0.07\;mmol\;m^{-2}\;d^{-1}$ ammonium $23\;{\pm}\;1\;mmol\;m^{-2}\;d^{-1}$ phosphate = $0.09\;{\pm}\;0.02\;mmol\;m^{-2}\;d^{-1}$ and silicate = $23\;{\pm}\;1\;mmol\;m^{-2}\;d^{-1}$.

• The Journal of Engineering Geology
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• v.23 no.2
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• pp.95-104
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• 2013

This study proposes an efficient management plan for improving the water quality of agricultural reservoirs. Hongdong reservoir is located in an area that includes farmland, forest, residential housing, and livestock farms. The levels of pollutants in Hongdong reservoir were investigated with the aim of improving the water quality in the reservoir. The potential concentrations of total nitrogen (T-N) and total phosphorus (T-P) in Hongdong reservoir were 1.06-3.67 and 0.52-1.12 $g/m^2-d$, respectively. An analysis of leaching characteristics was performed under anaerobic conditions for 72 hours at $20^{\circ}C$. The concentrations of T-P and $PO_4$-P were measured by general leaching for a set period. In the case of T-P, the leaching was measured by irregular leaching due to denitrification of nitrite nitrogen ($NO_2$-N) and nitrate nitrogen ($NO_3$-N). A very small amount of $NH_3$-N on nitrogen ($N_2$) was measured due to the low pH in the column, as a consequence of the anaerobic conditions.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.1
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• pp.159-170
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• 2007

Organic compost from the food waste and poultry manure is useful for a soil conditioner and fertilizer. The purpose of this study is to compare the effect of the food waste compost(FC) and poultry manure compost(PC) separately on the growth of young radish and the change of soil properties. Applying 3, 6, $9kg/m^2$ of FC and 1, 2, $3kg/m^2$ of PC, the cultivation of young radish was carried out in the crop field. In young radish applied with FC, leaf length was positively increased with the increasing usage of the compost. Number and area of leaves, and weight of leaf and root were peaked at applying rate of $6kg/m^2$. Growth of young radish with FC of $9kg/m^2$ was lowest in the initial period of the cultivation, and it is regarded that the applying rate of $9kg/m^2$ was detrimental to the germination of the young radish. In young radish applied with PC, the growth rate lowest at applying of $2kg/m^2$ than any other applying rate. Soil properties as bulk density and EC were considerably improved according to applying of food-waste and poultry manures compost. It should be considered to be needed additional study about the accurate applying rate and detailed investigation for soil properties.

• Journal of Environmental Impact Assessment
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• v.26 no.5
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• pp.331-343
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• 2017

The important changes in water environment management in Korea can be summarized as the enactment of Act on the Integrated Control of Pollutant-Discharging Facilities. Therefore water quality impact assessment should be reexamined and be revised. This study examines the present water quality impact assessment items (permissible discharge limits, standards for effluent water quality including Total Pollutant Load Management System) and considers the land use regulation for water quality conservation and NVZs(Nitrate Vulnerable Zones of EU and England). It also considers lately adopted standards(maximum discharge standards, permissible discharge standards, and marginal discharge standards etc) based on Act on the Integrated Control of Pollutant-Discharging Facilities and then compares Korean BAT and its counterpart control technology of U.S.A. And it also compares the items of water quality impact assessment with those of Integrated Control of Pollutant-Discharging Facilities, based on EIS reporting items. This study suggests five improvement measures for water quality impact assessment. First reflection of discharge impact analysis on impact prediction and assessment, second reflection of permissible discharge standards on agreed standards in the EIA procedure, third, reflection of diversified BAT on mitigation measures in the EIA procedure, forth introduction of land use regulation such as NVZs, finally strengthening linkage between water quality items and land use items etc.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.124-130
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• 2004

This study was carried out to evaluate the effects of condensed molasses soluble (CMS) treatment on the mineralization of N, chemical properties and soil microbial population under the incubation condition with unsaturated water content during the 7 weeks at $25^{\circ}C$ in the different levels of CMS application. The results indicated that the total nitrogen content of soil was increased with increasing application rate of CMS and this trend was maintained up to 7 weeks. With CMS treatment content of $NH_4-N$ was gradually decreased. However, the content of $NO_3-N$ in the soil was gradually increased with incubation time due to the nitrification under the unsturated water condition. The CMS treatment increased the microbial populations such as bacteria, actinomycetes and fungi, which may be due to the availability of more nutrients such as amino acids, sugars and other minor elements from CMS. The pH of soil was found to be reduced by the addition of CMS, Whereas, electrical conduvtivity of soil was correspondingly increased with increasing application rate of CMS.