• Korean Journal of Soil Science and Fertilizer
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• v.23 no.1
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• pp.8-14
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• 1990

Retardation and hydrodynamic dispersion coefficient necessary for model of water and solute movement in a soil were determined for horizontal soil column with different initial soil water conditions. The soil columns were compacted with sandy loam soil. The bulk density was $1,350+50kg/m^3$, and initial water contents were 0.05, 0.08 and 0.14. Advancement of 0.05% $CaSO_4$ solution was used as the standard and advancements of 0.5% KCl, $CaCl_2$ and $KH_2PO_4$ were compared. Retardation of non-reactive $Cl^-$ was related with the initial soil water content, ${\theta}n$, as ${\theta}/({\theta}-{\theta}n)$, and anion exclusion was ignored. Retardations of active $K^+$, $Ca^{{+}{+}}$ and $H_2PO_4{^-}$ were related as 1/(R+1) $^*{\theta}/({\theta}-{\theta}n)$, in which R was retardation coefficient. Measured R was 0.64 for $K^+$, 0.80 for $Ca^{{+}{+}}$ and 2.6 for $H_2PO_4{^-}$, respectively. Calculated R using Langmuir adsorption isotherm showed fair degree of applicability. Soil water diffusivity, $D({\theta}),m^2/sec$, calculated for different initial water content showed unique function as $$log(D({\theta}))=13.448{\theta}-9.288$$ Hydrodynamic dispersion coefficient of $Cl^-$ above soil water content 0.36 was similar to soil water diffusivity and decreased to near self diffusion coefficient at soil water content near 0.2. Those of $K^+$, $Ca^{{+}{+}}$ $H_2PO_4{^-}$ at soil water content of 0.38 were $5.5{\times}10^{-6}$, $2.4{\times}10^{-6}$ and $7.1{\times}10^{-7}m^2/sec$ and decreased rapidly with decreasing soil water content lower than 0.36.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.676-680
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• 2003

Dissolution of magnetite powders by 0.05 M citric acid was investigated at $50^{\circ}C$. All the tests were performed in the pH range between 2.0 to 5.0, which was adjusted using nitric acid or sodium hydroxide. Concentration of each of the dissociated chemical species of citric acid under various solution pHs was calculated using the ionization constants. Variation of zeta potential of magnetite with pH changes was also investigated. The dissolution reaction was explained by comparing the concentration of the dissociated chemical species of citric acid with the zeta potential. Longer than 3 h of induction time was required to dissolve the magnetite. The dissolution behaviour of magnetite was well described by the equation. The physical meaning of each parameter was explained successfully from the model equation.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.121-131
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• 2004

Removal efficiencies of soil washing and soil improvement processes to remediate farmland soils and stream deposits around Goro abandoned mine were investigated with batch and column experiments. For As-contaminated farm-land soils around Goro mine, batch tests to quantify As extraction rate from contaminated soils and lime treated contaminated soils were performed. The contaminated soil mixed with lime decreased As extraction rate less than one fourth, suggesting that the soil improvement method mixed with lime dramatically decrease As extraction rate. A storage dam will be constructed in the lower part of the main stream connected to Goro abandoned mine and the amount of As extracted from the bottom soils of reservoir could be the main source to contaminate water of reservoir. The decrease of As extraction amount from the bottom in reservoir, caused by the application of the soil improvement method was investigated from the physically simulated column experiment and results showed that As extraction rate decreased to one forty when 1％ lime mixed soil improvement was applied to contaminated soils. For contaminated stream deposits connected Goro mine, the removal efficiency of the soil washing method was investigated with batch experiments. Hydrochloric acid, citric acid, acetic acid and distilled water were used as soil washing solution and 0.01, 0.05, 0.1, 0.5, 1.0 N of washing solution were applied to extract As. When washing with 0.05 N of hydrochloric acid or citric acid, more than 99.9% of As was removed from stream deposits, suggesting that As contaminated stream deposits around Goro mine be successfully remediated with the soil washing process. Total volumes of contaminated soils and deposits needed for remediation were calculated based on three different reme-diation target concentrations and the operation cost of soil washing for calculated soil volumes was estimated. Results from this research could be directly used to make a comprehensive countermeasure to remediate contaminated area around Goro mine and also many contaminated areas similar to this research area.

• Journal of Soil and Groundwater Environment
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• v.13 no.5
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• pp.47-56
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• 2008

Temporal changes of metal solubility have been repeatedly observed in soils equilibrated with metal salt solutions. This phenomenon is known as aging, yet factors that affect the degree of metal aging remain largely unexamined. In this study, we compared the extent of aging on metal partitioning depending on soil, metal, and metal loading. Five soils spiked with four levels of Cd (2.5-20 mg ${kg}^{-1}$), Cu, and Zn (50-400 mg ${kg}^{-1}$) salt solutions were aged in the laboratory up to 1 year. The partitioning coefficient ($K_d$) of each metal was calculated from the ratio of total to dissolved metal concentration in samples collected at times ranging from 1 day to 1 year. The highest $K_d$ values for Cd, Cu and Zn were recorded in a Histosol, Andisol, and fine-textured Alfisol, respectively, whereas the lowest $K_d$ was recorded for an Oxisol and coarsetextured Alfisol. For all soils, a pattern of increasing Kd with aging was evident for Cd and Zn, but not Cu. Rapid Cu sorption was limited when dissolved organic matter was high in soils. In highly-retentive soils, $K_d$ values seemed to be insensitive to metal loading, although a longer period was required for the higher metal loadings to reach the same degree of metal aging as the lower loadings. In soils with low sorption capacity, the $K_d$ values were determined more by metal loading than by aging. Therefore, marked differences can be expected in the degree of metal aging in spiked soils by the soil type, metal and amount of metal added.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1996.09a
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• pp.61-76
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• 1996

본 연구는 하천유역의 중금속을 제거하는데 식물을 활용하기 위해 1994년 7월부터 10월까지 전라북도에 위치한 전주천과 그 주변하천에서 7개 지점을 선정하여 토양층과 물의 Pb, Cu, Zn 및 Fe 등의 함량을 조사하였고 그 주변에 자생하는 고마리, 마름 및 노랑어리연꽃의 중금속 농축량과 부위별 중금속 농축량을 조사하였다. 그리고 재료식물내의 중금속 농축량과 서식지 토양의 중금속 함량과의 관계를 밝히기 위해 재료식물내의 중금속 함유량과 토양의 중금속 함량간의 상관계수를 조사하였다. 실험실 조건하에서 재료식물의 중금속 흡수경향을 조사하기 위해 재료식물 중 고마리를 선정하여 Pb, Cu 및 Zn 등을 여러 농도로 처리한 용액에 고마리의 뿌리부분을 침수하여 재배한 후 그농축량을 측정하였고, 그 결과를 7개 채집지에서 자생한 고마리의 중금속 농축량의 측정치와 비교 분석하였다. 7개 채집지에서 자생한 고마리의 부위별 중금속 농축량은 Pb와 Zn의 경우 줄기<잎<뿌리의 순서로 증가하였고 Cu와 Fe는 잎<줄기<뿌리의 순서로 증가하였으며, 중금별 농축량은 Pb$\leq$Zn의 순서로 증가하였다. 고마리의 배양 실험 결과, 서식지에서 조사된 결과인 잎과 줄기에서 Pb

• Journal of Korea Soil Environment Society
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• v.1 no.2
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• pp.61-72
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• 1996

A series of batch and lab-scale continuous tests were conducted to optimize the design parameters for the full-scale in-situ soil flushing experiments. The cleaning abilities of the surfactant solutions of Tween 80, Triton X-100 and SDS were compared for the soil artificially contaminated by hydrophobic organic contaminants: n-dodecane, naphthalene and anthracene. Tween 80 and Triton X-100 were shown to be efficient for n-dodecane. SDS and Tween 80 were shown to be efficient for naphthalene and anthracene. At the end of each column test, the sorbed amount of surfactant to soil was also measured. Tween 80 was found to be the least adsorbed surfactant to soil. The flushing ability at flowrate of 7 ml/min, was hampered comparing to flowrate of 3 and 5 ml/min. Initial pH of the soil did not significantly affect the flushing efficiencies. Tween 80 was determined as the most harmless surfactant for the Gram(+) and Gram(-) bacteria.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.5
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• pp.342-347
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• 2008

Phosphate soubilized by microbes can be easily absorbed by plant as the element diffuses into soil solution. The microbes related to phosphate solubilizing activity are affected by the soil amendments such as rice straw compost, and lime. This study was performed to evaluate the effect of amendments to phosphate solubilizer in rice paddy soils. Available phosphate concentration was increased with the ratio of phosphate-solubilizing bacteria to aerobic bacteria in the rice paddy soils. The ratio was high in the plots applied with lime, silicate, and rice straw compost. Phosphate-solubilizing bacteria isolated from the soil were Aquasipirillum, Arthrobacter, Bacillus, Flavobacterium, Micrococcus and Micromonospora, Pseudomonas species. The highest dominant bacterial species was Pseudomonas, and Bacillus was followed.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.55-62
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• 1999

The solvent flushing apparatus for soil remediation was designed. After the soil around nuclear facilities was sampled and compulsorily contaminated by Co, the characteristics remediated by solvent flushing were analyzed. Meanwhile, the nonequilibrium sorption code was developed for modelling of the soil remediation by solvent flushing, input parameters needed for modelling were measured by laboratory experiment. Experimental results are as follows : The soil around nuclear facilities belongs to Silt Loam including a lot of silt and sand. When water was used as a solvent, the higher was the hydraulic conductivity. the higher the efficiency of soil remediation was. The values calculated by the nonequilibrium sorption code agreed with experimental values more exactly than the values calculated by the equilibrium sorption code. When EDTA solution was used as a solvent. the soil remediation efficiency by EDTA solution showed higher than that by water.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.1
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• pp.35-40
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• 1991

A laboratory column experiment was conducted to learn the desalinization effect of rice straw, fresh or predecayed in limed marine soil, compared with gypsum. One third of Ca equivalent to indigenous Na plus Mg of the soil was applied to the top 10g out of 80g of total column soil, mixing one half of it to the top soil and the rest spreading on the surface. 1. Pre-decaying of rice straw in limed marine soil promoted the permeability of column soil. but showed a less effectiveness in desalinization of sodium than lime alone or lime plus fresh rice straw treatemenents. 2. Gypsum and calcium carbonate treatments without rice straw fixed Mg in the limed top soil and washed it down disolving more from the layer immediatly be low the treated top soil But the treatment of calcium carbonate and rice straw both together washed out Mg more from lower layers than the upper's, showing only physical desalinization. 3. The desalinization of Na was also severe in the layer immediately below the $CaSO_4$ treated top soil, leauing more Na ilo the top soil, which seemed to be attributed to the peptisation of the top soil and retard peptisation of desalinization when washed the soil applying not enough amount or non of gypsum.

• Journal of Radiation Protection and Research
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• v.24 no.1
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• pp.1-7
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• 1999

Using the TBP slovent extraction method, a simple and precise method for determining uranium isotopes in the environment samples was developed. The soil sample was decomposed with $HNO_3$ and HF. Uranium isotopes were extracted with 15% TBP in $CCl_4$ from aqueous phase to organic phase, and Th fraction was removed with 8M HCl. Uranium fraction was purified in back extraction step with 1M HCl. Optimized electrode position conditions of uranium Isotopes were set using a new electrode position solution including a DTPA chelating agent. The new method of uranium isotopes determination was validated with a result of application to IAEA Reference Soils.