• Title/Summary/Keyword: Transport in soil

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Improvement of K+ and Na+ Ion homeostasis and salt tolerance by Co-inoculation of arbuscular mycorrhizal fungi (AMF) and spore associated bacteria (SAB)

  • Selvakumar, Gopal;Kim, Kiyoon;Roy, C. Aritra;Jeon, Sunyong;Sa, Tongmin
    • Proceedings of the Korean Society of Crop Science Conference
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    • pp.246-246
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    • 2017
  • Salinity inhibits plant growth and restricts the efficiency of arbuscular mycorrhizal fungi. The selective uptake of nutrients from the soil and their effective transport to host roots make it essential for plant growth and development under salt stress. AMF spore associated bacteria shown to improve mycorrhizal efficiency under stress. Thus, this study aimed to understand the co-inoculation efficiency of AMF and SAB on maize growth and ion homeostasis under salt stress. Two AMF strains and one SAB were inoculated with maize either alone or in combination with one another. The results of our study showed that AMF and SAB co-inoculation significantly improved dry weight and nutrient uptake of maize under salt stress. Co-inoculation significantly reduced proline accumulation in shoots and Na+ accumulation in roots. Co-inoculation treatment also exhibited the high K+/Na+ ratios in roots at 25 mM NaCl. Mycorrhizal colonization showed positive influence for regulation of ZmAKT2, ZmSOS1 and ZmSKOR gene expressions, contributing to K+ and Na+ ion homeostasis. CLSM view showed that SAB were able move and localize into inter and intra cellular spaces of maize roots. In addition, CLSM view of AMF spores showed that gfp-tagged SAB also associated on the spore outer hyaline layer.

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Interpretation of the Chemical Transformation of Individual Asian Dust Particles Collected on the Western Coast of Korean Peninsula

  • Ma, Chang-Jin;Kim, Jong-Ho;Kim, Ki-Hyun
    • Asian Journal of Atmospheric Environment
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    • v.6 no.1
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    • pp.14-22
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    • 2012
  • This paper is focused on the comprehensive and detailed interpretation for the chemical transformation of individual Asian dust (hereafter called "AD") particles during long-range transport from source regions to receptor area. A multi-stage particle sampler was operated at a ground-based site in Taean, Korea directly exposed to the outflow of air masses from China during AD period in April 2003. Both quantitative and qualitative analyses for size-classified individual particles were carried out by a microbeam X-ray fluorescence (XRF) method and a microbeam Particle Induced X-ray Emission (micro-PIXE), respectively. Among major characteristic elements, the elemental masses of soil derived components, sulfur, and chloride varied as a function of particle size showing the monomodal maximum with a steeply increasing at 3.3-4.7 ${\mu}m$ particle size. Although the details on chemical composition of AD particle collected on a straight line from source area to our ground-based site are needed, a large amount of Cl coexisted in and/or on AD particles suggests that AD particles collected in the present study might be actively engaged in chemical transformation by sea-salt and other Cl containing pollutants emitted from the China's domestic sources. Through the statistical analyses it was possible to classify individual AD particles into six distinct groups. The internally mixed AD particles with Cl, which has various sources (e.g., sea-salt, coal combustion origin HCl, gaseous HCl derived from the adsorption of acids to sea-salt, and Cl containing man-made particles) were thoroughly fractionated by the elemental spectra drivened by the double detector system of micro-PIXE.

Variability of Pb, Mn, Al and Na Concentrations is Snow Deposited from Winter to Early Summer 1998 in Livingston lsland, Antarctic Peninsula

  • Sungmin Hong;Lee, Gangwoong;Velde, Katja-Van de;Claude F. Boutron
    • Journal of Korean Society for Atmospheric Environment
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    • v.16 no.E2
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    • pp.85-96
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    • 2000
  • The concentrations of Pb, Mn, Al and Na were measured from a total of 26 snow samples collected from a 1.5-m deep snow pit in Livingston Island, South Shetland Islands, at the northern tip of the Antarctic Peninsula. Ore sampling location is great concern, because of its proximity to the southern extremity of south America, a candidate for the source regions of pollutant aerosols entering Antarctica. The mean concentrations of Pb and Mn were found to be 4.97 pg g(sup)-1 and 20.6 pgg(sup)-1, respectively. These concentrations levels are similar to those reported for recent snow at other Antarctic sites with pronounced spring maxima for both metals. Contributions form natural sources are estimated to be minor (∼16%) for Pb. For Mn, on the other hand, contribution from rock and soil dusts is found to be very important. Excess Pb over Pb from natural sources is likely to be anthropogenic, especially from South Americal. Our results show that yearly Pb fallout flux is much greater in Antarctic coastal areas than at other Antarctic locations far from the coast , indicating that the transport and deposition patterns of pollutant aerosols are not simple is Antarctica. It is also suggested that the recycling of anthropogenic Pb in seawater to the atmosphere could significantly contribute to the Pb fallout flux in the Antarctic coastal regions.

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Comparison of ELLAM and LEZOOMPC for Developing an Efficient Modeling Technique (효율적인 수치 모델링 기법 개발을 위한 ELLAM과 LEZOOMPC의 비교분석)

  • Suk Hee-Jun
    • Journal of Soil and Groundwater Environment
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    • v.11 no.1
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    • pp.37-44
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    • 2006
  • This study summarizes advantages and disadvantages of numerical methods and compares ELLAM and LEZOOMPC to develop an efficient numerical modeling technique on contaminant transport. Eulerian-Lagrangian method and Eulerian method are commonly used numerical techniques. However Eulerian-Lagrangian method does not conserve mass globally and fails to treat boundary in a straightforward manner. Also, Eulerian method has restrictions on the size of Courant number and mesh Peclet number because of time truncation error. ELLAM (Eulerian Lagrangian Localized Adjoint Method) which has been popularly used for past 10 years in numerical modeling, is known for overcoming these numerical problems of Eulerian-Lagrangian method and Eulerian method. However, this study investigates advantages and disadvantages of ELLAM and suggests a change for the better. To figure out the disadvantages of ELLAM, the results of ELLAM, LEZOOMPC (Lagrangian-Eulerian ZOOMing Peak and valley Capturing), and visual MODFLOW are compared for four examples having different mesh Peclet numbers. The result of ELLAM generates numerical oscillation at infinite of mesh Peclet number, but that of LEZOOMPC yields accurate simulations. The simulation results suggest that the numerical error of ELLAM could be alleviated by adopting some schemes in LEZOOMPC. In other words, the numerical model which combines ELLAM with backward particle tracking, forward particle tracking, adaptively local zooming, and peak/valley capturing of LEZOOMPC can be developed for not only overcoming the numerical error of ELLAM, but also keeping the numerical advantage of ELLAM.

Development of a Conjunctive Surface-Subsurface Flow Model for Use in Land Surface Models at a Large Scale: Part II. Model Implementation (대규모 육지수문모형에서 사용 가능한 지표면 및 지표하 연계 물흐름 모형의 개발: II. 모형적용)

  • Choi, Hyun-Il
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.3
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    • pp.23-27
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    • 2008
  • The new conjunctive surface-subsurface flow model at a large scale was developed by using a 1-D Diffusion Wave (DW) model for surface flow interacting with the 3-D Volume Averaged Soil-moisture Transport (VAST) model for subsurface flow for the comprehensive terrestrial water and energy predictions in Land Surface Models (LSMs). A selection of numerical implementation schemes is employed for each flow component. The 3-D VAST model is implemented using a time splitting scheme applying an explicit method for lateral flow after a fully implicit method for vertical flow. The 1-D DW model is then solved by MacCormack finite difference scheme. This new conjunctive flow model is substituted for the existing 1-D hydrologic scheme in Common Land Model (CLM), one of the state-of-the-art LSMs. The new conjunctive flow model coupled to CLM is tested for a study domain around the Ohio Valley. The simulation results show that the interaction between surface flow and subsurface flow associated with the flow routing scheme matches the runoff prediction with the observations more closely in the new coupled CLM simulations. This improved terrestrial hydrologic module will be coupled to the Climate extension of the next-generation Weather Research and Forecasting (CWRF) model for advanced regional, continental, and global hydroclimatological studies and the prevention of disasters caused by climate changes.

Model Development for Specific Degradation Using Data Mining and Geospatial Analysis of Erosion and Sedimentation Features

  • Kang, Woochul;Kang, Joongu;Jang, Eunkyung;Julien, Piere Y.
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.85-85
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    • 2020
  • South Korea experiences few large scale erosion and sedimentation problems, however, there are numerous local sedimentation problems. A reliable and consistent approach to modelling and management for sediment processes are desirable in the country. In this study, field measurements of sediment concentration from 34 alluvial river basins in South Korea were used with the Modified Einstein Procedure (MEP) to determine the total sediment load at the sampling locations. And then the Flow Duration-Sediment Rating Curve (FD-SRC) method was used to estimate the specific degradation for all gauging stations. The specific degradation of most rivers were found to be typically 50-300 tons/㎢·yr. A model tree data mining technique was applied to develop a model for the specific degradation based on various watershed characteristics of each watershed from GIS analysis. The meaningful parameters are: 1) elevation at the middle relative area of the hypsometric curve [m], 2) percentage of wetland and water [%], 3) percentage of urbanized area [%], and 4) Main stream length [km]. The Root Mean Square Error (RMSE) of existing models is in excess of 1,250 tons/㎢·yr and the RMSE of the proposed model with 6 additional validations decreased to 65 tons/㎢·yr. Erosion loss maps from the Revised Universal Soil Loss Equation (RUSLE), satellite images, and aerial photographs were used to delineate the geospatial features affecting erosion and sedimentation. The results of the geospatial analysis clearly shows that the high risk erosion area (hill slopes and construction sites at urbanized area) and sedimentation features (wetlands and agricultural reservoirs). The result of physiographical analysis also indicates that the watershed morphometric characteristic well explain the sediment transport. Sustainable management with the data mining methodologies and geospatial analysis could be helpful to solve various erosion and sedimentation problems under different conditions.

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Fate and Transport of Cr(VI) Contaminated Groundwater from the Industrial Area in Daejeon (대전 산업단지 지하수의 6가 크롬 오염 및 확산 평가)

  • Chon, Chul-Min;Moon, Sang-Ho;Ahn, Joo-Sung;Kim, Yung-Sik;Won, Jong-Ho;Ahn, Kyoung-Hwan
    • Economic and Environmental Geology
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    • v.40 no.4
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    • pp.403-418
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    • 2007
  • The objective of this research was to characterize the fate and transport of Cr(VI) contaminated groundwater in the Daejeon industrial area. Five subsidiary monitoring wells were newly installed and two existing wells were utilized for the investigation and the reduction process of Cr(VI) contaminated groundwater of the Daejeon(Mun-pyeong) national groundwater monitoring station. The Cr(VI) concentrations at the shallow aquifer well of the station were in the range of 3.2-4.5 mg/L indicating continuous contamination. However, Cr was not detected at the deep bedrock well and the other monitoring wells except MPH-1 and 3. The Cr(VI) concentrations of MPH-1 and MPH-3 were below the drinking water guideline value (0.05 mg/L). Therefore, the plume of the Cr(VI) contaminated groundwater was predicted to be confined within the narrow boundary around the station. The soluble/exchangeable Cr(VI) concentrations were below the detection limit in all core and slime samples taken from the five newly installed wells. Although the exact source of contamination was not directly detected in the study area, the spatial Cr(VI) distribution in groundwater and characteristics of the core samples indicated that the source and the dispersion range were confined within the 100 m area from the monitoring station. The contamination might be induced from the unlined landfill of industrial wastes which was observed during the installation of an subsidiary monitoring well. For the evaluation of the natural attenuation of Cr(VI), available reduction capacities of Cr(VI) with an initial concentration of 5 mg/L were measured in soil and aquifer materials. Dark-gray clay layer samples have high capacities of Cr(VI) reduction ranging from 58 to 64%, which is obviously related to organic carbon contents of the samples. The analysis of reduction capacities implied that the soil and aquifer materials controlled the dispersion of Cr(VI) contamination in this area. However, some possibilities of dispersion by the preferential flow cannot be excluded due to the limited numbers of monitoring wells. We suggest the removal of Cr(VI) contaminated groundwater by periodical pumping, and the continuous groundwater quality monitoring for evaluation of the Cr(VI) dispersion should be followed in the study area.

Numerical Simulation of Groundwater Flow in Feterogenetic Rockmass of Unsaturated Condition (암반의 불균질성을 고려한 불포화대 지하수 유동 평가)

  • Ha, Jaechul;Lee, Jeong Hwan;Cheong, Jae-yeol;Jung, Haeryong
    • The Journal of Engineering Geology
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    • v.26 no.1
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    • pp.87-99
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    • 2016
  • We present the results of two-dimensional numerical simulations predicting the flow of groundwater in a fractured unsaturated zone. We applied the k-field distribution of permeability derived from discrete fracture network (DFN) modeling as the hydraulic properties of a model domain. To model an unsaturated zone, we set the depth from the ground surface to the underground aquifer. The rate of water infiltration into the unsaturated zone was divided into two parts, an artificial structure surface and unsaturated soil zone. The movement of groundwater through the unsaturated zone was simulated with particular emphasis on contaminant transport. It was clearly observed that the contaminants dissolved in groundwater transported vertically from the ground surface to the saturated zone.

Determination of the Fracture Hydraulic Parameters for Three Dimensional Discrete Fracture Network Modeling (3차원 단열망모델링을 위한 단열수리인자 도출)

  • 김경수;김천수;배대석;김원영;최영섭;김중렬
    • Journal of the Korean Society of Groundwater Environment
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    • v.5 no.2
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    • pp.80-87
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    • 1998
  • Since groundwater flow paths have one of the major roles to transport the radioactive nuclides from the radioactive waste repository to the biosphere, the discrete fracture network model is used for the rock block scale flow instead of the porous continuum model. This study aims to construct a three dimensional discrete fracture network to interpret the groundwater flow system in the study site. The modeling work includes the determination of the probabilistic distribution function from the fracture geometric and hydraulic parameters, three dimensional fracture modeling and model calibration. The results of the constant pressure tests performed in a fixed interval length at boreholes indicate that the flow dimension around boreholes shows mainly radial to spherical flow pattern. The fracture transmissivity value calculated by Cubic law is 6.12${\times}$10$\^$-7/ ㎡/sec with lognormal distribution. The conductive fracture intensity estimated by FracMan code is 1.73. Based on this intensity, the total number of conductive fractures are obtained as 3,080 in the rock block of 100 m${\times}$100 m${\times}$100 m.

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Source Identification of Ambient Size-by-Size Particulate Using the Positive Matrix Factorization Model on the Border of Yongin and Suwon (PMF 모델을 이용한 용인-수원경계지역에서의 부유분진의 크기별 오염원 확인)

  • Oh, Mi-Seok;Lee, Tae-Jung;Kim, Dong-Sool
    • Journal of Korean Society for Atmospheric Environment
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    • v.25 no.2
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    • pp.108-121
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    • 2009
  • The suspended particulate matters have been collected on membrane filters and glass fiber filters by an 8-stage cascade impactor for 2 years (Sep. 2005${\sim}$Sep. 2007) in Kyung Hee University-Global Campus located on the border of Yongin and Suwon. The 20 chemical species (Al, Mn, Si, Fe, Cu, Pb, Cr, Ni, V, Cd, Ba, $Na^+$, ${NH_4}^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, ${NO_3}^-$, and ${SO_4}^{2-}$) were analyzed by an ICP-AES and an IC after performing proper pre-treatments of each sample filter. Based on these chemical information, the PMF receptor model was applied to identify the source of ambient size-by-size particulate matters. The receptor modeling is the one of the statistical methods to achieve resonable air pollution management strategies. A total of 10 sources was identified in 9 size-ranges such as long-range transport, secondary aerosol, $NH_{4}NO_{3}$ related source, coal combustion, sea-salt, soil, oil combustion, auto emission, incineration, and biomass burning. Especially, the secondary aerosol source assorted in fine and coarse modes was intensively studied.