• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.310-313
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• 2003

The precipitation of heavy metals within the region of pH jump is inevitable in the conventional electrokinetic remediation technology. This study prevents the interest species from precipitating through the injection of flushing solutions in which HCl, acetic acid, citric acid, EDTA and SDS dissolved. The cumulative flow resulted from electroosmosis appear in order of Citric acid

• Korean Journal of Environmental Agriculture
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• v.19 no.1
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• pp.75-79
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• 2000

To investigate seasonal variations of soil solution chemistry, samples were collected from zero tension lysimeters in O, A, and B horizons of 26-year-old Larix leptolepis. Pinus koraiensis and Quercus mongolica stands in Kwangju, Kyunggi Province from September, 1996 through June. 1999. Potassium, $Mg^{2+}$, $Cl^-$, and $No_3\;^-$ concentrations increased in October and November concurrent with inputs of fresh litterfall and twigs. Sodium, $Ca^{2+}$, $K^+$, and $Mg^{2+}$ concentrations increased in March and April concurrent with the yellow sand effect. Potassium concentration showed the highest variation among ions, and $Cl^-$ concentration showed positive correlations with $K^+$ and $Mg^{2+}$ concentrations. Soil solution pH decreased while $Al^{3+}$ and $K^+$ concentrations increased during the study period. If our data reflects long term trends. then $Al^{3+}$ concentration in the O horizon will reach the toxic level (0.180 meq/l) within 10-20 years depending on species.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.9
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• pp.670-676
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• 2011

Artificially metal-contaminated soils have been widely used for lab-scale soil washing and soil toxicity experiments. The artificial soil contamination methods consist of 1) first equilibrating soils with heavy metal solution, 2) filtrating or centrifuging soils from the mixture and 3) finally drying the soils. However, some of those artificially contaminated soil experiments have not clearly shown that the soils were thoroughly rinsed with water prior to conducting experiments. This study investigated the amount of heavy metal release from the artificially metal-contaminated soil by pre-water-rinsing. Three different artificially metal-contaminated soil preparation methods were first evaluated with Cd and Pb concentrations of soil. Then, this study investigated the effect of pre-water-rinsing on the Cd and Pb concentration of the artificially contaminated soil. Heavy metal concentrations of the soil produced by equilibrating and drying the metal solution-soil were significantly reduced by pre-water-rinsing. The results of the study implied that experimental results would be significantly distorted when the artificially heavy metal-contaminated soils were not thoroughly water-rinsed prior to conducting experiments. Therefore, the initial heavy metal concentration of the artificially contaminated soil should be determined after thoroughly rinsing the soil that was previously obtained through the adsorption and dry stages.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.551-561
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• 2007

This case study is about the sampling and interpretation of soil pore water in order to understand and to predict the diffusion and behavior of soil pollution. For the measurement of polycyclic aromatic hydrocarbons(PAHs) in two representative hydrocarbon-contaminated sites, the extraction system of the soil pore water was set up with respect to soil depths and the behavior of contaminants was interpreted. The soil solution extraction system consisted of peristaltic pump, and extraction and sampling compartment, and can measure simultaneously the soil water pressure. The concentration of PAHs with respect to extraction pressure and time decreased due to dilution through soil pore water. Particularly, the concentration of PAHs was more reduced under the unsaturated oxic condition than saturated anoxic condition. Therefore, the soil solution extraction with respect to soil water pressure can interpret the extent of equilibrium between porewater and soil surface.

• Journal of Soil and Groundwater Environment
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• v.16 no.6
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• pp.46-57
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• 2011

In this study, analytical solution of multip-species transport equations coupled with a first-order reaction network under constant concentration boundary condition or total flux boundary condition is obtained using similarity transformation approach of Clement et al. (2000). The study shows the schematic process about how multi-species transport equations with first-order sequential reaction network is transformed through the similarity transformation approach into independent and uncoupled single species transport equations with first-order reaction. The analytical solution was verified through the comparison with popular commercial programs such as 2DFATMIC and RT3D. The analytical solution can be utilized in nuclear waste sites where radioactive contaminants and their daughter products occur and in industrial complex cities where chlorinated solvent such as PCE, TCE, and its biodegradation products produces. In addition, it can help the verification of the developed numerical code.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.241-247
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• 2012

Many infectious diseases have emerged or re-emerged during the past 50 years in South Korea. There were three outbreaks of foot and mouth disease (FMD) in South Korea between January 2010 and March 2011. Over 3.45 million animals were slaughtered (33.3% of the existing pigs, 8.4% of dairy cows and 3.4% of cattle). To select optimal degradation agents of animal cadavers, degradation rates and fertilizer components of pig cadavers were investigated using hydrogen chloride (HCl), potassium hydroxide (KOH) and sodium hydroxide (NaOH) hydrolysis methods. Degradation rates of pig cadavers using HCl, KOH and NaOH were 81.1, 82.8 and 91.6%, respectively. Total nitrogen (T-N) concentration in degradation solution of pig cadavers using KOH hydrolysis method was higher than that in NaOH and HCl hydrolysis methods. Total phosphorus ($P_2O_5$) concentrations in degradation solution of pig cadavers in all hydrolysis methods ranged 0.14 ~ 0.28%. Total potassium ($K_2O$) concentration for KOH hydrolysis method was higher than that for other hydrolysis methods. The concentration of T-N and $K_2O$ in degradation solution of pig cadavers by KOH hydrolysis method were higher than that in NaOH and HCl hydrolysis methods. Thus, to recycle animal cadavers in agriculture, the optimal degradation agent for hydrolysis was KOH.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.2
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• pp.115-121
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• 1987

A pot experiment was conducted to investigate the influence of Ca and Mg saturation ratios of soil on the uptake of Ca, Mg and K by rice plant. A silty loam soil was treated with $CaCl_2$ and $MgCl_2$ to obtain different degrees of Ca and Mg saturation. The studied ranges of Ca and Mg saturation ratios were 81:19, 70:30, 52:48, 55:45, and 31:69 in terms of the ratio of exchangeable Ca and Mg. Two levels of K application (90kg/ha, and 180kg/10a as $K_2O$) were also included in this study. The significant observation were summarized as follows. 1. When the Ca saturation of soil was dominant over Mg, the soil solution contained more Ca than Mg and vice versa. These led to the higher uptake of Ca by rice plant in Ca dominant soils and higher uptake of Mg in Mg dominant soils. 2. When the Ca and Mg saturation ratio was about equal, more Mg was released to soil solution leading to higher concentration of Mg in rice plant compare to that of Ca. 3. A trend was observed that the concentration of K in soil solution was lower in Mg dominant soils than in Ca dominant soils. This also resulted in the depressed uptake of K by rice plant under Mg dominant system when compare to Ca dominant system. 4. The increase application of K led to the increase in relative concentration of K to (Ca+Mg+K), and to the depression of divalent uptake by rice plant. However, it was observed that the degree of depression in uptake divalent by K application was more sensitive in case of Mg than that of Ca. 5. When viewed from grain yield of rice, it is pointed out that the optimum range of Ca to Mg ratio in soil may fall in the vicinity of 7:3. 6. Although K uptake by rice plant was influenced by the term of $AK^+/{\sqrt{A(Ca^{{+}{+}}+Mg^{{+}{+}})$ in soil solution, $AK^+$ itself was affected by the ratios of Ca:Mg in soil, as it were $AK^+$ value was decreased in Mg dominant soil than in Ca.

• Journal of Soil and Groundwater Environment
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• v.18 no.7
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• pp.25-31
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• 2013

Hydrogen peroxide takes much of the cost for Fenton reaction applied for treatment of organic contaminants. Therefore, the effective use of hydrogen peroxide makes the technology more cost effective. The effective use of hydrogen peroxide is especially needed in the soil and groundwater remediation where complete mixing is not possible and it takes a long time for reactive species to transport to the fixed target compounds. Stabilization ability for hydrogen peroxide of malonic acid was evaluated in Fenton and Fenton-like reactions in this study. Malonic acid contributes on the stabilization of hydrogen peroxide by weak interaction between iron and the stabilizer and inhibiting the catalytic role of iron. The stabilization effect increased as the solution pH decrease below the $pK_{a1}$. The stabilization effect increased as the concentration of malonic acid increased and the effect was maximized at the malonic acid concentration of about ten times higher than the iron concentration. The model organic contaminant was successfully oxidized in the presence of the stabilizer but the degradation rate was slower than the system without the stabilizer. The stabilization effect was also proved in a Fenton-like reaction where magnetite and hematite were used instead of soluble iron species.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.87-101
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• 1999

This study has been carried out to examine the feasibility of washing technique for reducing the heavy metal contamination level of tailing wastes and agricultural soil surrounding abandoned metal mines. Some organic acids with low molecular weight were used as washing solution. Initial contamination levels of copper and lead for some soil samples were found to exceed the standard levels of countermeasure and concern, and those of cadmium to approach the standard level of countermeasure. Experimental results using sequential extraction method revealed that more than half of copper and lead existing in tailing wastes are adsorbed forms available for plants. There are some proportional relationships between metal concentrations determined by using 0.1N HCI solution and those determined by sequential extractions. Citric acid was turned out to be superior to oxalic acid and acetic acid with low molecular weight in washing above three metals. When citric acid is used for washing heavy metals from soil, it is desirable to operate at pH less than 5.5 for better washing effect. Metal removal effect by citric acid solution has been proved to depend upon solution concentration and the mass ratio of solution to soil. Addition of SDS(Sodium Dodecyl Sulfate) to citric acid improved the washing effect of cadmium among three metal most significantly. while copper removal did not change. Washing technique using citric acid for removal of heavy metals from agricultural soil or tailing wastes is recognized to be an effective remediation method.

• Nuclear Engineering and Technology
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• v.34 no.3
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• pp.242-249
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• 2002

The relationship between the tritium release rate from the nuclear power plant and tritium concentration in the environment around the Kori site was modeled. The tritium concentration in the atmosphere was calculated by multiplying the release rates and $\chi$/Q values, and the d3V deposition rate at each sector according to the direction and the distance was obtained using a dry deposition velocity. The area around Kori site was divided into 6 zones according to the deposition rate. The six zones were divided into 14 compartments for the numerical simulation. Transfer coefficients between the compartments were derived using site characterization data. Source terms were calculated from the dry deposition rates. Tritium concentration in surface soil water and groundwater was calculated based upon a compartment model. The semi-analytical solution of the compartment model was obtained with a computer program, AMBER. The results showed that most of tritium deposited onto the land released into the atmosphere and the sea. Also, the estimated concentration in the top soil agreed well to that measured. Using the model, tritium concentration was predicted in the case that the tritium release rates were doubled.