• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.316-329
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• 2005

Mobility of pesticides can be occurred by run-off and leachate or soil erosion. It is one of the most important factors for environmental contamination, particularly in steep sloped-land as Gangwon alpine region. In this study, the mobility of seven pesticides in different slopes and soil textures was investigated by simulated rainfall under controlled conditions. Simulated rainfall subjected to 60 mm $hr^{-1}$ was treated using rainfall simulator after 12 hr of pesticide treatment. Amounts of the pesticides were measured in run-off and leachate samples. The soil samples collected after rainfall from upper and lower parts and three different depths of sloped-plot were also analyzed. At result, all pesticides from the un-off samples collected from Taebaek(silty clay loam) and Heongseong(sandy loam) soils were detected maximum 96% within 60 minutes after first collection except carbendazim and cypermethrin which have the lowest water solubilities. From the leachate samples, a similar pattern was shown as run-off samples but amount of pesticides was lower than those of run-off samples. In soil samples, the order of the amount of pesticide residues was $0{\sim}5$ > $5{\sim}10$ > $10{\sim}15$ cm of soil depth and no pattern was shown in upper and lower, and different slopes. Comparing to mobility of pesticides in water and soil samples, pesticides in soil samples were higher than those of water samples in Taebaek soil. However, the results using Heongseong soils were in contrast to those of Taebaek soil. These results revealed that mobility of pesticides can be dependant mainly on soil textures and physicochemical properties of pesticides. Therefore, it can be suggested that selection of pesticides should be considered for soil texture and properties of pesticide in the alpine and sloped-land.

• Journal of Korean Society on Water Environment
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• v.22 no.4
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• pp.720-726
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• 2006

Long-term monitoring results of water qualities at major lakes in Korea showed COD (chemical oxygen demand) concentrations have been increasing while BOD (biochemical oxygen demand) concentrations have been decreasing during last decades. This was mainly due to refractory organic matters have been accumulated in the water body. In this study, the possible causes of COD concentration increase were evaluated. From the statistics, it can be understood that potent pollutant sources including fertilizer consumption, population, livestock, and carbon uptake have increased. Leaching tests were carried out with soils and biomasses sampled at agricultural-forestry area. From the leaching experiments, leachate qualities as a ratio of $COD_{Cr}/BOD$ were in the range of 2.5-5.0, implying that NOM (natural organic matters) discharged from the forestry area was mainly responsible for the COD accumulation. It can be understood from this research that diffuse pollutants from forestry areas should be controlled properly to reduce COD accumulation in the lakes.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.321-328
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• 2002

Various geosynthetics used as liners or the Protection layers are installed in the solid waste landfill. The interface shear strength between geosynthetics installed at the slope of the landfill is a very important variable for the safe design of bottom and cover systems in the solid waste landfill. The interface shear strengths between (1) Geomembrane(GM)/Geotexile(GT) and (2) Geomembrane(GM)/Geosynthetic Clay Liner(GCL) were estimated by a large direct shear test in this study and were evaluated by the Mohr-Coulomb failure criterion. Especially, this research is focused on the effect of water which exists between geosynthetics because interfaces become easily wet or hydrated by rain, leachate and groundwater beneath liners. The strength reduction at large displacement and the effects of the magnitude of normal stresses and GCL hydration methods also investigated. The test results showed that the interface shear strength and shear behavior varied depending upon the magnitude of normal stresses, water at the interface, and hydration methods. Summary of secant friction angles, which could be used as reference values at a site where similar geosynthetics are installed, together with normal stress and hydration condition are presented.

• Journal of Soil and Groundwater Environment
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• v.6 no.3
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• pp.107-117
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• 2001

The characteristics of groundwater movement under the heavy rainfall at Nan-ji waste landfill site are studied using HELP(Hydraulic Evaluation of Landfill Performance) program, which calculates the daily leachate in the Nan-ji waste landfill site. In this study, instead of the average recharge value, which is used in the past study, the real reacharge value is used to calculate the daily leachater. It is found about 70 times greater than thor average recharge value under the condition of heavy rainfall in the rainy season. The flow characteristics of groundwater for water level fluctuation is simulated using the ground water flow model MODFLOW(A Modular 3-D Finite Different Groundwater Flow Model) program, and the slurry layer is newly added. The result of the study is different from that of the ordinary simulation, which shows much higher ground water level than from the ordinary simulation.

• Journal of Soil and Groundwater Environment
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• v.26 no.5
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• pp.39-48
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• 2021

Analysis of the change in water content and distribution was conducted according to the supply of recirculation water to a landfill. An excavation sample analysis showed that the recirculation water injection zone had water content 8.8% point higher than that of the non-injection zone, after 8 months of operation. And due to the influence of recirculation water supply by vertical wells in injection zones, the water content increases along with depth more clearly than non-injection zone. According to an electrical specific-resistivity survey after 13 months of operation, the water content got higher towards the bottom of the landfill. The water transmission coefficient is 8.72×10^-4 cm/sec for injection zones and 3.36×10^-5 cm/sec for the intermediate cover layer; analysis shows that the intermediate cover layer may affect the penetration velocity of water supplied by the horizontal injection tube. For the scientific design and operation of re-injection facilities, it was deemed necessary to follow-up research on the residence time and behavior of re-injection water considering the ratio of recirculation water supply in horizontal and vertical tubes, and pitcher coefficient of intermediate and waste layers.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.717-724
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• 2012

Salt accumulated soil should be reclaimed to lower salt level for crop production. This study was carried out to investigate the characteristics of water flow and transport of mono and divalent solutes on salt accumulated soils with different head pressures. Saturated hydraulic conductivity was measured by constant and falling head methods with maintaining different head pressures. Saturated hydraulic conductivity was influenced by bulk density and organic matter contents in soils, but it had different elusion patterns between saline and sodic soil. While the quantity of water necessary for reclamation could be varies with soil type, it was considered that the supply of one pore volume of water was affordable and economic. Additional head pressure significantly increased the volume of leachate at a given time and it was more effective at low organic matter soils. The results indicate that additional head pressure would be one of the best irrigation practices on desalination method for salt accumulated soils.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.48-52
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• 2011

The effect of soil water content on the transformation potential of N compounds derived from hydrolysis of urea applied in a reclaimed tidal soils which was saline-sodic was observed to evaluate nitrification rates of urea. Soil samples were collected from Moonpo series at the newly reclaimed area in Saemanguem. For the transformation potential of N compounds from urea (46% N), newly reclaimed tidal soils (RS) were amended with urea at the rates of 0, 10, and 20 kg $10a^{-1}$. With leachate obtained from the incubated RS in a leaching tube at $25^{\circ}C$, urea hydrolysis and nitrification were measured for a total of 30days. The cumulative amounts of $NO_3{^-}$-N in each of the four soils treated with urea was linear with time of incubation. Results showed that increase in pH occurred with increasing application rate of urea and volumetric water content due to hydrolysis of urea. The total N in the RS was decreased with incubation time, indicating that rates of urea hydrolysis was influenced by soil moisture conditions. Also, the cumulative amount of nitrate in RS gradually increased with increase in time of incubation.

• Journal of Environmental Health Sciences
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• v.28 no.2
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• pp.99-108
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• 2002

This study was carried out to evaluate the Physicochemical characteristics of mined waste(separated waste and soil) and to predict environmental effect of an old landfill site located at north of Seoul. Municipal solid waster(MSW) had been disposed of at the old landfill site used in this study for about 2 years(1990-1992). The old landfill site selected for this study had accepted mainly municipal solid waste. The landfill-mined waste contained separated waste (40.9%) and soil(59.1%) by wet weight basis. The separated waste consisted of combustible(91.0%) and non-combustible(9.0%). The combustible waste was mainly non-biodegradable plastics. The low heating value of the separated combustible waste, which is calculated by Dulong's equation, was as high as 3,470kcal/kg. According to the Korean Extraction Procedure, separated waste and soil were proved to be not hazardous. The total content of heavy metal in the separated waste and soil met standard of California State, USA. Therefore the separated waste may be relandfilled at a sanitary landfill site and/or burned up at an incinerator, and the separated old soil may be used ad landfill cover-soil at a sanitary landfill site. Water quality of two streams was grade IV, of which water could be used as industrial and agricultural water. The streams near the landfill site might not be contaminated by leachate from the old landfill site. It was estimated that organic matter in the old landfill site would not be actively biodegraded within a short period of time.

• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.155-160
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• 2007

Constructed wetland has been widely used for the treatment of sewage, stormwater runoff, industrial wastewater, agricultural runoff, acid mine drainage and landfill leachate. For the removal of nitrogen and phosphorus, uptake by plants and adsorption to media material are the major processes, and, therefore, the selection of media with specific adsorption capacity is the critical factor for the optimal design of wetland along with the selection of appropriate plant species. In this study, two media materials (loess bead and mixed media) possessing different adsorption characteristics for ammonium and phosphate were selected, and their adsorption characteristics were evaluated. In addition, the performance of subsurface-flow wetland systems employing these media was evaluated in both batch and continuous flow systems. With LB medium, beter phosphorus removal was observed, while better ammonia removal was obtained with MM medium. In addition, enhanced removal efficiencies were observed in the wetland systems employing both media and aquatic plants, mainly due to the better environment for microbial growth. As a result, appropriate selection or combination of media with respect to the inflow water quality maybe important factors for the successful design and operation of wetland systems.

• Journal of Korean Society of Disaster and Security
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• v.10 no.1
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• pp.55-60
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• 2017

The dyeing sludge can be weakened by inflow of rainfall or absorption of moisture after it is buried in a waste landfill. This study tested the dyeing sludge and earth/sand mixture to check the problem when the dehydrated dyeing sludge is buried in a waste landfill. When the dyeing sludge was left idle with high water content inside a landfill with poor draining for a long period, the water permeability decreased to around 3/100 level and the compressibility increased by 1.4 times compared to the dyeing sludge at a dyeing factory. The study result indicated that it was important to reduce the water content inside the landfill for stability. Also, the facilities to secure the drainage path and eliminate leachate were needed.