• Environmental Engineering Research
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• v.23 no.4
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• pp.462-473
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• 2018

The uranium ore residues from the legacies of past uranium mining and milling activities that resulted from the less stringent environmental standards along with the uranium residues from the existing nuclear power plants continue to be a cause of concern as the final uranium residues are not made safe from radiological and general safety point of view. The deposition of uranium in ponds increases the risk of groundwater getting contaminated as these residues essentially leach through the upper unsaturated geological formation. In this context, a numerical model has been developed in order to forecast the $^{238}U$ and its progenies concentration in an unsaturated soil. The developed numerical model is implemented in a hypothetical uranium tailing pond consisting of sandy soil and silty soil types. The numerical results show that the $^{238}U$ and its progenies are migrating up to the depth of 90 m and 800 m after 10 y in silty and sandy soil, respectively. Essentially, silt may reduce the risk of contamination in the groundwater for longer time span and at the deeper depths. In general, a coupled effect of sorption and hydro-geological parameters (soil type, moisture context and hydraulic conductivity) decides the resultant uranium transport in subsurface environment.

• Economic and Environmental Geology
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• v.46 no.5
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• pp.425-444
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• 2013

This study was carried out in order to determine the remediation of total petroleum hydrocarbons (TPHs), trichloroethylene (TCE), perchloroethylene (PCE), benzene, toluene, ethylbenzene and xylenes (BTEX) compounds for non-aqueous phase liquids (NAPLs) using in-situ air sparging (IAS) / vapor extraction (VE) with the marine sediments of Mandol, Hajeon, Sangam and Busan, South Korea. Surface sediment of Mandol area had sand characteristics (average particle size, 1.789 ${\Phi}$), and sandy silt characteristics (average particle size, 5.503 ${\Phi}$), respectively. Sangam surface sediment had silt characteristics (average particle size, 5.835 ${\Phi}$). Sediment characteristics before experiment in the Busan area showed clay characteristics (average particle size, 8.528 ${\Phi}$). TPHs level in the B1 column of Mandol, Hajeon, Sangam, and Busan sediments were 2,459, 6,712, 4,348, and 14,279 ppm. B2 (3 L/min) to B5 (5 L/min) columns reduced 99.5% to 100.0% of TCE and 93.2% to 100.0% of PCE. Removal rates of TCE, PCE, and BTEX are closely correlated (0.90-0.99) with particle sizes and organic carbon concentrations. However, TPHs (0.76) and benzene (0.71) showed the poorer but moderate correlations with the same parameters.

• Economic and Environmental Geology
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• v.44 no.3
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• pp.203-215
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• 2011

Geochemical and mineralogical properties of a contamited soil should be taken into account to decide a remediation strategy for a given contaminant because development and optimization of soil remedial technologies are based on geochemical and mineralogical separation techniques. The objective of this study was to investigate the geochemical and mineralogical characteristics of arsenic-contaminated soils. The arsenic-contaminated soil samples were obtained from Chonam gold mine, Gwangyang, Chonnam, Particle size analysis, sequential extraction, and mineralogical analyses were used to characterize geochemical and mineralogical characteristics of the As-contaminated soils. Particle size analyses of the As-contaminated soils showed the soils contained 17-36% sand, 25-54% silt, 9-28% clay and the soil texture were sandy loam, loam, and silt loam. The soil pH ranged from 4.5 to 6.6. The amount of arsenic concentrations from the sequential soil leaching is mainly associated with iron oxides (1 to 75%) and residuals (12 to 91%). Major minerals of sand and silt fractions in the soils were feldspar, kaolinite, mica, and quartz and minor mineral of which is an iron oxide. Major minerals of clay fraction were composed of illite, kaolinite, quartz, and vermiculite. And minor minerals are iron oxide and rutile. The geochemical and mineralogical analyses indicated the arsenic is adsorbed or coprecipitated with iron oxides or phyllosilicate minerals. The results may provide understanding of geochemical and mineralogical characteristics for the site remediation of arsenic-contaminated soils.

• Journal of The Geomorphological Association of Korea
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• v.27 no.1
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• pp.33-45
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• 2020

A number of unconsolidated deposits, consisting of a layer of gravels and silt, are found in Dangjeong-ri, Seocheon-gun in the western coast. From below in the stratigraphic sequence, the gravel layer ranging up to a maximum thickness of about 2 meters is interpreted as being formed by fluvial processes of an old channel (Dangjeong S.), and the overlying silt or sandy silt layer of 2 to 3 thickness meters is assumed to be emerged paleo-tidal sediments which was deposited in low tidal-energy environments. As the results of rock surface IRSL datings, the depositional ages of gravels are confirmed as ca. 78,000 ~ 83,000 years BP, indicating that the layer was formed in response to a high-stand sea level of MIS 5a along the Dangjeongcheon estuary. It is presumed that the relative height of 4.5 meter between the altitude of the stream bed (9.5 m) and the altitude of the bedrock boundary in the gravel layer (14 m) indicates the uplift amount since deposition. Paleo-sedimentary environments and an altitude of paleo-shoreline in the study area will be discussed with additional age dating focused on the silt layer.

• Journal of the Korean Geotechnical Society
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• v.38 no.2
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• pp.5-13
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• 2022

The unsaturated behavior of sandy silt (SM soil) was investigated experimentally. Special attention was given to the stress-strain behavior of unsaturated weathered soil (SM) prior to failure and behavior at failure under monotonic loading. A sandy silt (SM) weathered soil containing a certain amount of fine contents distributed in Korea, was chosen to form samples with different densities of Dr=25%, 60%, and 75%. and matric suctions. The isotopically Consolidated Drain test (CD-test) was performed to maintain a constant matric suction during the shearing process. Based on the experimental results, it was qualitatively identified that the higher the relative density, the greater the virtual friction angle (ϕ^b) value and AEV (Air Entry Value) were induced. Also it is found that the internal friction angle (ϕ') is more or less constant. even if the matric suction is increased.

• The Korean Journal of Quaternary Research
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• v.3 no.1
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• pp.35-45
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• 1989

In Korean peninsula as well as in Western European Countries, we can find, reddish bands in sandy deposits of various origin. These bands (called "$B_t$ Band"), composed of fine material, are regularly intervalled and parallel to topography. This study is tring to elucidate their origin and associated milieux, with a group of methods and techniques (field survey, micromorphological analysis, granulometry, X-ray diffractometry of clay minerals...). $B_t$ Bands are not sedimentological origin. They were formed by superposition of two type accumulations in the sandy profile, triggered by different mechanisms: 1) accumulation in banded form, concerning silty heterometric material and micas, oweing to cryophoretic forces operating in course of deep freezing of sandy deposits: 2) illuviation of ferrugineous clays in the precedants bands, migrated in chelate state by soil water. The first processes are associated with very cold and humid climate in which freeze soil more than 3m in depth. The second, cold and humid climate in which podzolizattion is generalized. In case of South Korea and Western Europe, these two types of climates are not present circumstance, but Recent Quaternary (probably since the Wurm).the Wurm).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.278-284
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• 1995

This experiment was performed to characterize the optimum water table level for the grain quality, seed germination and diastic power of barley(var. Olbori) and wheat(var. Grumil). Olbori and Grumil grew in the 550 liter plastic pot that filled with silt loam or sandy loam. During the whole growth period, the underground water level adjusted to be 20, 30, 40, 50 and 70cm. Filled grain ratio and specific gravity were not affected by soil texture and water table. Low level of water table caused the increase of 1,000 grain weight in wheat and barley, but soil texture didn't. Crude protein content tended to be high as the water table level was high, especially in wheat. Change in crude protein content was affected by underground water level more than soil texture. And the affection was slightly higher in sandy loam than silt loam, but the difference was small. The higher level of water table led to the lower crude lipid content in barley and wheat grain. Crude lipid content of both wheat and barley grain grown in sandy loam was higher than those grown in silt loam. As the water table level down, the ash content of barley and wheat grain tend to increase, especially in sandy loam. Wheat flour yield was not affected by soil texture. It was about 65% at 20cm of water level and above 67% at 40cm water level. The seed germination of wheat and barley was more than 95% when the seeds were placed at 2$0^{\circ}C$ for three days. Regardless of soil texture, the lowest germination was seen at 20cm of water table level. And the seed germination rate increased as the underground water level became low. Above 89% of barley grains were germinated within 48 hours except 20cm level of water table in sandy loam. Diastic power of germinated barley was the lowest at 20cm of water table level, and it was almost unchanged below 30cm of water table level. And also it was not affected by soil texture.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.6
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• pp.793-804
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• 1995

Polychaetous community survey in Tomioka Bay was carried out 5 times seasonally from May 1991 to March 1992 by quantitative grab sampling (0.05m2) at 11 stations. Based on the granulometric composition and environmental factors, a homogeneous soft bottom was found in St.5-10. The species of the polychaete were classified into three feeding groups using the Fauchald and Jumars' feeding guild system. According to polychaetous community composition data, deposit feeders predominate in sandy silt area where the silt-clay content is $60-69.3\%.$ These deposit feeders were subdivided into surface deposit feeders and subsurface deposit feeders by their living position and mode. Also, suspension feeding group comes as the third dominant group. Seasonal changes of each feeding group were described in terms of numerical density and biomass. Feeding layer and types of dominant species (Lumbrineris longifolia: surface deposit feeder; Praxillella pacifica: subsurface deposit feeder; Chone duneri; suspension filter feeder, etc.) were examined in the intact sediment core samples. Also, longterm density change among the three dominant species during 10 years was disussed.

• The Korean Journal of Quaternary Research
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• v.9 no.1
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• pp.43-60
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• 1995

The Kanweoldo Deposit in the Cheonsoo Bay western coast of Korean Peninsula is considered to be influenced by severe freezing condition under cold humid environment of the last glacial age. The evidence of severe freezing in the some upper part of the fine-grained Kanweoldo Deposit is characteristically irregular wavy la-mellar structure with the interval of 2∼8mm. In particular lamina show very compacted fabrics composed of rounded or spheroidal discrete aggregates covered by silt caps. Such laminar structure and associated micro-fabrics might owe to soil freezing such as ice segregation in lens form cryophoresis pressure from growing ice and disturbance by frost-creep. Furthermore pedogenesis of cold-humid type such as gleyzation or peseudo-gleyzation also might af-fect the kanweoldo Deposit in the priod of severe cold-humid cli-mate of the Wrm. The Kanweoldo sediment and organic remnant(16,708 B.P. with error limit of 250 years) affected by severe cryogenic activities sug-gest that the paleoclimate of Late Wrm in Korea might be so cold and humid as to engender the cryogenic structure in subaerial silty and sandy silt deposits.

• Journal of the korean society of oceanography
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• v.32 no.3
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• pp.120-127
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• 1997

Depositional environment off the Shihwa Dam has been studied to investigate the change of sedimentation process and the pollution. In order to understand how the sediments are distributed, polluted and modified, depositional factors have been analyzed and compared with the previous data. Study area, located off the Shihwa Dam, was surveyed to collect 25 bottom samples and 2 cores in 1996 and echo-sounding in 1997. These sediments were analyzed for the study of the global characteristics of sediment such as grain size and organic matter. Among these samples, the selected twenty surface sediments were analyzed for the comparison with their contents of metallic elements (Al, Mn, Fe, V, Cr, Co, Ni, Cu, Zn, Cd, Pb, As). According to field and lab analysis of sediments, three sedimentological zones have been generally identified around study area; near the dam (sandy Silt), near the dike (Sand) and offshore (silty Sand) zones. Textural parameters show that the content of silt and clay is dominant near the dam excepting the dike zone of LNG Storage Base and offshore (Palmido). The total concentration of Mn, Ni, Fe, Zn and Cd in bulk sediments was increased after the construction of the dam, while the content of Mn and Cr were higher near tidal channel than in the offshore area. Meanwhile, the annual increasing pattern of some heavy metal has appeared in this area. Based on this primary study, modification of the depositional environment may be caused by the construction of the dam and LNG Storage Base. Additionally, environmental evaluation on organic/inorganic factors has been suggested for interpreting environmental changes caused by coastal development in the nearshore such as the Shihwa coastal area.