• Journal of Environmental Impact Assessment
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• v.24 no.1
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• pp.1-15
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• 2015

To mitigate the impacts of climate change on agricultural ecosystems, development of agricultural management for enhanced soil carbon sequestration is required. In this study, the effects of fertilizer types (chemical fertilizer and manure compost), cropping systems, and crop residue management on SOC(Soil Organic Carbon) sequestration were investigated. Summer corn and winter barley were cultivated on experimental plots under natural rainfall conditions for two years with chemical fertilizer and manure compost. Soil samples were collected conducted and analyzed for SOC for soil. To estimate long-term variation patterns of SOC, DNDC was run with the experimental data and the weather input parameters from 1981 to 2010. DNDC simulation demonstrated SOC reduction by chemical fertilizer treatment unless plant residues are returned; whereas compost treatments increased SOC under the same conditions and SOC increment was proportional to compost application rate. In addition, SOC further increased under corn-barley cropping system over single corn cropping due to more compost application. Regardless of nutrient input type, residue return increased SOC; however, the magnitude of SOC increase by residue return was lower than by compost application.

• Journal of Environmental Impact Assessment
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• v.21 no.5
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• pp.649-664
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• 2012

The grid cell analysis is used to select good sites as habitats at the region. The northern area of Yeongjong Island, Incheon has been disturbing by habitat loss due to human activities such as residential development, deforestation. In order to determine significant places as bird habitats and to select conservation areas at this island, the study area was divided into 70 grid cells($500{\times}500m$ each grid) and then each grid was ranked by spatial analysis using the species diversity index. Fieldwork was carried out in Spring and Autumn of 2010. To examine grid cells which were ranked high in both seasons in common, we used the average ranking value, combined data from two seasons. This area consists of mainly agricultural areas and forests(more than 68%) among eight habitat types: the agricultural land, forest, coast, lake, meadow, stream, city and other things. A total of 110 species was recorded: 4,183 birds of 102 species in Spring and 3,326 birds of 58 species in Autumn. In other words, the number of individuals and species was higher in Spring than in Autumn. Species diversity index presented the highest value at M8 grid cell in Spring(3.380) and at A4 gird cell in Autumn(2.736). In 18 of 22 grid cells where the average ranking value was higher than 3, the forest was distributed and in 4 grid cells, the coast and wetland were widely distributed, in which theses were located apart from human-associated disturbances such as construction works for a leisure complex. Our results present a new estimate method not only to minimize loss of bird habitats but also to conserve important habitats when the large-scale development takes place at particular region.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.6
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• pp.454-459
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• 2009

In this paper, we have performed an experimental study to simultaneously remove humic acid (RA) and heavy metals (Cu, Mn, and Zn) from the river water using potassium ferrate(VI), a multi-purpose and environment-friendly chemical. In the experiments for treating three 0.1 mM single heavy metals using 0.03${\sim}$0.7 mM (as Fe) ferrate, the removal efficiencies ranged 28${\sim}$99% for Cu, 22${\sim}$73% for Mn, and 18${\sim}$100% for Zn. In addition, humic acid and heavy metals could be very efficiently removed at the same time using 0.03${\sim}$0.7 mM (as Fe) ferrate: for example, 49${\sim}$81% (humic acid), 93${\sim}$100% (Cu), 22${\sim}$86% (Mn), and 20${\sim}$100% (Zn). The removal efficiencies of humic acid and heavy metals in the mixture of humic acid and heavy metals were higher than that in the solution of single humic acid or heavy metal. It can be explained by the fact that, before adding ferrate to the mixed solution, part of solutes were already removed by the complexation between the negatively-charged functional groups of humic acid and heavy metal cations.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.167-168
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• 2003

The Upo wetland, the largest natural wetland in Korea, is located in Changnyeong-gun, Gyeongsannam Province ($35^{\circ}33'$ N, $128^{\circ}25'$ E), and 70 km upstream from the Nakdong River estuary. Unlike most other Korean wetlands that have been destroyed under the name of economic development, the Upo wetland has been able to preserve its precious ecosystem throughout the years. Thanks to increased public awareness about natural wetlands and environmental conservation, the Korean Ministry of Environment designated the Upo wetland an 'Ecological Conservation Area' on July 26th, 1997. On March 2nd of the following year, the Upo wetland (8.54 $\textrm{km}^2$) was designated a 'Protected Wetland' in accordance with the international Ramsar Treaty. A 4.49m long (from 9.73 to 5.24 m in altitude) UP-1 core ($35^{\circ}33'05"N$, $128^{\circ}25'17"E$), recovered in the marginal part of the Upo wetland, is divided into eight buried paleosol units of different ages on the basis of the abundance of color mottles and vertical color variations (Aslan et al., 1998). Radiocarbon datings suggested that the paleosol profile represent the last 5700 years. The entire section of the core was more or less subjected to pedogenetic processes, and shows very weak to moderate soil profile development. These Holocene paleosols are therefore regarded as synsedimentary soils of deluvium (deposits formed by floods) origin (Sycheva et al., 2003). Unit 1 to 5 paleosols are generally silt-rich and exhibit moderate profile development. The boundaries between the units are somewhat distinguishable, but not so clear cut. This is due to variable repeated combination of accumulation, denudation and soil forming processes within various periods. Mottle textures gradually decrease in abundance with increasing clay content in Unit 6, which results in weak profile development. The lower boundary of Unit 6 lies around about 2000 yrBP, the beginning of Subatlantic in Korea (Kim et al., 2001). Abrupt sediment textural change is detected in Unit 7, which is interpreted to indicate the human activities on the Upo wetland. Unit 8 represents the recent soil forming processes. The preliminary results of this ongoing study imply the primary factor for pedogenetic processes is the water table fluctuations related to the sedimentary textures like grain size distributions, and the geomorphological stability of the Upo wetland.o wetland.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.2
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• pp.159-169
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• 2004

Sedimentation and depositional pattern of the fine-grained sediments in the southeastern inner shelf of Korea were studied using a very high-resolution seismic profiles and sediment data. The recent mud deposits up to 45 m thick are distributed in the inner shelf forming a nearshore belt from the eastern part of Geoje Island to off the Pohang along the coast. The sediment in this area consists of homogeneous mud with mean grain size between $8.6\;to\;5.3\phi$ and does not show any distinct variability It gradually becomes finer and well sorted northeastward along the coast. Sediments normally appear as structureless massive mud but X-radiographs show that some bioturbation and faint lamination are present. The sediments accumulate at a rate of 0.18-0.44 cm/yr and the rate coincides well with the long-term (a 1000-year scale) accumulation based on very high-resolution seismic data. Distribution of wet bulk density and velocity shows a gradual increase from the southeastern part of Ulsan to off Pohang, whereas porosity shows a reverse pattern. Correlations between velocity and porosity/mean grain size are different from other regions compared, due to the difference of sediment texture and sedimentary environment. The recent shelf deposits are seismically characterized by three distinct facies: 1) well-stratified (near the river mouth), 2) semi-transparent (eastern part of Geoje Island), and 3) transparent (off Ulsan). The results suggest that fine-grained sediment derived from rivers, forming a nearshore mud belt, have been transported northeastward by the northeastward-flowing coastal current.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.7
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• pp.705-711
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• 2008

In case of the domestic condition, as the initiating from Sumjin River Dam, total 14 units of multipurpose dams had been constructed in 1965 for the roles of flood control, waterpower generation, irrigation, water supply, industrial water supply. In the case of such multipurpose dam, it produces electric energy by converting the potential energy utilizing its head and quantity of the water into kinetic energy. However, in this process, since during the time when the turbine connected to the hydraulic turbine dynamo revolves and there occurs a loud noise, it brings the physical, mental bad influences to those people also a decline of an effective working efficiency. On such point of view, after selection of various 16 measurement points, this study has measured and analyzed the travelling characteristics of noise generated at the hydraulic turbine dynamo in Daechung Dam, and also has evaluated the degree of indoor noise using the evaluation index such as PSIL, NC. As the result of noise-evaluation, in case of Daechung Dam, since the noise damage grade appears very seriously at various spaces, it is considering that its soundproof measure would be necessitated keenly. Also, it is considered that such data could be utilized as the valuable material hereafter for establishment of an efficient noise-reduction countermeasure and a comfortable working environment for the hydraulic turbine dynamo plant.

• The Korean Journal of Pesticide Science
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• v.21 no.1
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• pp.75-83
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• 2017

The single residue analytical method was developed for determining fungicide pencycuron residues in various agricultural commodities with high-performance liquid chromatography (HPLC). Pencycuron residue was extracted with acetone from representative crops such as Korean cabbage, apple, brown rice and green pepper. After ethyl acetate/n-hexane partition and subsequent clean-up with silica gel chromatography, pencycuron residue was quantified by reversed phase HPLC with UV detection at 240 nm. The suspected residue of pencycuron was confirmed using selected-ion monitoring (SIM) LC/mass spectrometry (MS). Instrumental limit of quantitation (ILOQ) and method LOQ (MLOQ) were set at 2 ng and 0.02 mg/kg, respectively. Overall recoveries of pencycuron from different crop samples fortified at three levels (MLOQ, 10MLOQ, 100MLOQ) were 72~108%. This proposed method could be useful as official analytical method for quantification of pencycuron residues in agricultural commodities.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.2
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• pp.126-135
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• 2015

Increase of delivery effect of pollutant loads and surface runoff due to urbanization of catchment area results in serious environmental problems in receiving urban streams. This study aims to develop integrated stormwater management system to assist efficient urban stream flow and water quality control using information from the Storm Water Management Model (SWMM), real time water level and quality monitoring system and remote or automatic treatment facility control system. Based on field observations in the study site, most of the pollutant loads are flushed within 4 hours of the rainfall event. SWMM simulation results indicates that the treatment system can store up to 6 mm of cumulative rainfall in the study catchment area, and this means any type of normal rainfall situation can be treated using the system. Relationship between rainfall amount and fill time were developed for various rainfall duration for operation of stormwater treatment system in this study. This study can further provide inputs of river water quality model and thus can effectively assist integrated water resources management in urban catchment and streams.

• Korean Journal of Remote Sensing
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• v.33 no.2
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• pp.111-123
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• 2017

The phycocyanin pigment (PC) is a marker for cyanobacterial presence in eutrophic inland water. Accurate estimation of low PC concentration in turbid inland water is challenging due to the optical complexity and criticalforissuing an early warning of potentialrisks of cyanobacterial bloom to the public. To monitor cyanobacterial bloom in eutrophic inland waters, an approach is proposed to partition non-water absorption coefficient from measured reflectance and to retrieve absorption coefficient of PC with the aim of improving the accuracy in remotely estimated PC, in particular for low concentrations. The proposed inversion model retrieves absorption spectra of PC ($a_{pc}({\lambda})$) with $R^2{\geq}0.8$ for $a_{pc}(620)$. The algorithm achieved more accurate Chl-a and PC estimation with $0.71{\leq}R^2{\leq}0.85$, relative root mean square error (rRMSE) ${\leq}39.4%$ and mean relative error(RE) ${\leq}78.0%$ than the widely used semi-empirical algorithm for the same dataset. In particular, low PC ($PC{\leq}50mg/m^3$) and low PC: Chl-a ratio values of for all datasets used in this study were well predicted by the proposed algorithm.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.5
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• pp.323-334
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• 2020

Adsorption by granule activated carbon(GAC) is recognized as an efficient method for the removal of perfluorinated compounds(PFCs) in water, while the poor regeneration and exchange cycles of granule active carbon make it difficult to sustain adsorption capacity for PFCs. In this study, the behavior of PFCs in the effluent of wastewater treatment plant (S), the raw water and the effluents of drinking water treatment plants (M1 and M2) located in Nakdong river waegwan watershed was monitored. Optimal regeneration and exchange cycles was also investigated in drinking water treatment plants and lab-scale adsorption tower for stable PFCs removal. The mean effluent concentration of PFCs was 0.044 0.04 PFHxS g/L, 0.000 0.00 PFOS g/L, 0.037 0.011 PFOA g/L, for S wastewater treatment plant, 0.023 0.073 PFHxS g/L, 0.000 0.00 PFOS g/L, 0.013 0.008 PFOA g/L for M1 drinking water treatment plant and 0.023 0.073 PFHxS g/L, 0.000 0.01 PFOS g/L, 0.011 0.009 PFOA g/L for M2 drinking water treatment plant. The adsorption breakthrough behaviors of PFCs in GAC of drinking water treatment plant and lab-scale adsorption tower indicated that reactivating carbon 3 times per year suggested to achieve and maintain good removal of PFASs. Considering the results of mass balance, the adsorption amount of PFCs was improved by using GAC with high-specific surface area (2,500㎡/g), so that the regeneration cycle might be increased from 4 months to 10 months even if powdered activated carbon(PAC) could be alternatives. This study provides useful insights into the removal of PFCs in drinking water treatment plant.