• Journal of Environmental Health Sciences
• /
• v.28 no.5
• /
• pp.65-70
• /
• 2002

Recently, surfactants were frequently used in order to desorb the hydrophobic organic compounds (HOCs) from soil and to enhance the bioavailability. Among them, -cyclodextrin ($\beta$-CD) is one of those. This study was performed to investigate the binding characteristics between benzene and $\beta$-CD and to examine the bioavailability of benzene. First, we investigated binding characteristics between benzene and $\beta$-CD in water and water/soil system. Then, we examined the effect of $\beta$-CD on the biodegradation of benzene in water and water/soil system. Experimental results on the binding characteristics showed that $\beta$-CD resulted in an efficient complex formation with benzene. As -CD concentration increased, the benzene concentration complexed with $\beta$-CD rapidly increased to 30-40% initial benzene added, and reached the equilibrium. We also investigated the effect of $\beta$-CD on the desorption of benzene from soil in the water/soil system. As $\beta$-CD concentration increased, benzene concentration desorbed into water increased up to 90%. How-ever, in its application to biodegradation of benzene in water and water/soil system, the biodegradation rate of benzene did not improved in the presence of $\beta$-CD compared with in the absense of $\beta$-CD. This result indicated that $\beta$-CD was more preferentially used as a carbon source than benzene. Therefore, for remediation of benzene contaminated soils, $\beta$-CD can be used as a surfactant to desert benzene from soil, and then ex-situ chemical treatment can be applied for the remediation.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.529-534
• /
• 2009

Climate models, both global and regional, have increased in sophistication and are being run at increasingly higher resolutions. The Land Surface Models (LSMs) coupled to these climate models have evolved from simple bucket models to sophisticated Soil-Vegetation-Atmosphere Transfer (SVAT) schemes needed to support complex linkages and processes. However, some underpinnings of terrestrial hydrologic parameterizations so crucial in the predictions of surface water and energy fluxes cause model errors that often manifest as non-linear drifts in the dynamic response of land surface processes. This requires the improved parameterizations of key processes for the terrestrial hydrologic scheme to improve the model predictability in surface water and energy fluxes. The Common Land Model (CLM), one of state-of-the-art LSMs, is the land component of the Community Climate System Model (CCSM). However, CLM also has energy and water biases resulting from deficiencies in some parameterizations related to hydrological processes. This research presents the implementation of a selected set of parameterizations and their effects on the runoff prediction. The modifications consist of new parameterizations for soil hydraulic conductivity, water table depth, frozen soil, soil water availability, and topographically controlled baseflow. The results from a set of offline simulations are compared with observed data to assess the performance of the new model. It is expected that the advanced terrestrial hydrologic scheme coupled to the current CLM can improve model predictability for better prediction of runoff that has a large impact on the surface water and energy balance crucial to climate variability and change studies.

• Journal of Korean Society of Forest Science
• /
• v.83 no.4
• /
• pp.473-479
• /
• 1994

This study was carried out to get the basic data for obtaining water resources continuously. Water storage of forest land was estimated by effective water storage based on classifying soil pore. The results were summarized as follows ; 1. Percentage of coarse pores were in the order : Forest>Bare land>Grasses. As soil depth increased, total pores, coarse pores, and maximum water content were decreased, while fine pores increased. 2. Soil pore percentage and physical properties of surface layer(0~20cm) were significantly different among forest floor conditions. However, there were no difference in soil pore percentage and physical properties in 20~40cm and 40~60cm according to forest floor conditions. In the same plot, on the other hand, soil pore percentage and physical properties were significantly different between surface layer(0~20cm) and 20~40cm, but there were no differences between 20~40cm and 40~60cm. 3. Effective water storage was highly correlated with coarse pore in all plots. 4. The model for water storage capacity of each forest floor condition expressed by effective water storage was produced using coarse pores and soil depth.

• Journal of Soil and Groundwater Environment
• /
• v.15 no.6
• /
• pp.81-90
• /
• 2010

In this study, primary investigation for evaluation of abandoned metal mine effect on watershed has been done. 64 abandoned mines have been selected for primary investigation through literature and field survey. 216 soil and 90 water samples were collected and metal pollution concentrations were analyzed. 24 mines have mine water in the pits and acid water below pH 5 was not observed. Soils from 35 mines were over the soil basis of concern and 16 mines were over the soil basis of action. Arsenic average concentration was 188 times of average concentration of the natural background. Drinking water samples from 3 mines were over the drinking water standard and surface water samples from 12 mines were over the river water standard. Integrated pollution index, which was resulted from the integration of field survey, soil and water pollution concentration, showed that, abandoned metal mines had affected on watershed greatly in the order of Samgeum, Daedeok, Cheongdalgeum, Heungsin, Yeongdae and Myeongbong mines.

• 한국생물공학회:학술대회논문집
• /
• 2000.04a
• /
• pp.418-421
• /
• 2000

A model was developed to describe the microbial decontamination of diesel contaminated soil in a soil column. The biodegradation rate of diesel in nature depends on temperature and the pH of soil, availability of nutrients, oxygen and water. The soil moisture content is one of the essential factors because it characterizes the availability not only of water to microorganisms but also of oxygen and nutrient dissolved in soil. In this work, the rate of biodegradation was modeled by coupling Michaelis-Menten kinetics for the aqueous-phase solute with adsoption-desoption equation for diesel sorption and desorption from soil.

• Korean Journal of Soil Science and Fertilizer
• /
• v.25 no.4
• /
• pp.311-324
• /
• 1992

Polymeric substances in organic matter of soils aggregate soil particles into a crumb structure which greatly influences such properties as water movement, aeration and heat transfer. Poorly-structured soils may be improved by the incorporation of synthetic polymers where the main objects are : promoting germination or establishing crops, improving drainage, combating wind and water erosion, and reducing evaporation from the surface of soil under arid condition.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2002.09a
• /
• pp.86-88
• /
• 2002

The mathematical model was proposed to simulate ozone transport and remediation in unsaturated soils contaminated with phenanthrene. Soil column experiments were also carried out to calibrate the mathematical model. The experimental results successfully matched with the modeling results in various soil conditions. The model proposed nondimensional fraction factor to reveal reactivity between phenanthrene and gas phase ozone and liquid phase ozone. From sensitivity analysis, the fraction factor and stoichiometric coefficient decreased as water content increased. Simulation results showed increased SOM content retarded the ozone transport and the phenanthrene removal due to increased ozone consumption.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2002.10a
• /
• pp.96-103
• /
• 2002

In this study, design concepts of Seoul Subway Construction (901∼914) are reviewed in relation to the cases for temporary soil support wall systems which are revealed in highly developed design competitions such as Turnkey and Alternative based on. Especially soil and rock properties, various design schemes for dealing with soil and water pressures, new technology adopted etc are discussed very profoundly and broadly for the better understanding and additional clues for constructing new design technologies.

• Korean Journal of Soil Science and Fertilizer
• /
• v.16 no.2
• /
• pp.98-105
• /
• 1983

Differences in fertilizer responses of Chinese cabbage to soil water status were investigated in a field experiment. The growth pattern, water use, nutrient uptake, apparent efficiency of fertilizer and yield were analyzed under the 4-different fertilizer levels (N-P-K rate, kg/10a: 0-0-0 Fo, 11.5-10-12.5 Fo.5, 23-30-25 F1.0, 34.5-30-37.5 F1.5 and under the 4-different soil water status levels (non irrigated plot Mo, -0.1 to -1.0 bars M1, -0.1 to -0.5 bars M2, -0.1 to -0.2 bars M3). The soil was Bonryang sandy loam in the experimental farm of the Institute of Agricultural Sciences, Suweon. The growth and yield responses to the fertilizer levels showed a large difference between F0 and F0.5 but little differences were recognized between F0.5, F1.0 and F1.5 when the soil water potentials at 20-cm soil depth were lower than -2.0 bar. Under the well irrigated soil conditions, M2, and M3, the growth and yield responses to the fertilizer levels were significantly increased and the nutrient requirements were increased as well. The total uptake of nutrients decreased as the fertilizer amounts increased when the soil water potentials were low, while the total uptake of nutrients increased when the soil water potentials were high. Therefore, in considering nutrient availability of the applied fertilizers, the soil water status should be taken into account.

• Journal of Wetlands Research
• /
• v.18 no.2
• /
• pp.132-147
• /
• 2016

In this study the Microwave Imaging Radiometer using Aperture Synthesis (MIRAS) sensor onboard the Soil Moisture Ocean Salinity (SMOS) and Advanced Microwave Scanning Radiometer 2 (AMSR2) sensor onboard the Global Change Observation Mission-Water (GCOM-W1) based soil moisture retrievals were revised to obtain better accuracy of soil moisture and higher data acquisition rate over East Asia. These satellite-based soil moisture products are revised against a reference land model data set, called Global Land Data Assimilation System (GLDAS), using Cumulative Distribution Function (CDF) matching and regression approach. Since MIRAS sensor is perturbed by radio frequency interferences (RFI), the worst part of soil moisture retrieval, East Asia, constantly have been undergoing loss of data acquisition rate. To overcome this limitation, the threshold of RFI, DQX, and composite days were suggested to increase data acquisition rate while maintaining appropriate data quality through comparison of land surface model data set. The revised MIRAS and AMSR2 products were compared with in-situ soil moisture and land model data set. The results showed that the revising process increased correlation coefficient values of SMOS and AMSR2 averagely 27% 11% and decreased the root mean square deviation (RMSD) decreased 61% and 57% as compared to in-situ data set. In addition, when the revised products' correlation coefficient values are calculated with model data set, about 80% and 90% of pixels' correlation coefficients of SMOS and AMSR2 increased and all pixels' RMSD decreased. Through our CDF-based revising processes, we propose the way of mutual supplementation of MIRAS and AMSR2 soil moisture retrievals.