• Economic and Environmental Geology
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• v.30 no.6
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• pp.587-601
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• 1997

This study had three purposes: (1) to investigate the enrichment levels and dispersion patterns of potentially toxic elements in the rock-soil-plant system; (2) to evaluate the uptake ratios of heavy metals from soils into plants and (3) to assess the chemical speciation of heavy metals in soils. Rock, surface soil and plant samples were collected in the Boeun area underlain by black shales of the Okchon Zone. These samples were analyzed for multi-elements using INAA, ICP-AES and AAS. The maximum abundance of U in black shales is 16 mg/kg and radioactivity counts up to 300 cpm. In particular, Mo, V, Ba, Cd, Pb and U are enriched in black shales. Most of soils derived from black shales show high concentrations of U, As, Mo, Ba, Cu, Cd, Pb, Zn and mean concentrations of As and Mo in soils (20 mg/kg of As and 6.6 mg/kg of Mo) are higher than the permissible level suggested by Kloke (1979). Enrichment index values of soils are calculated and higher than 1.0 in the black shale area with the highest value of 6.4. Mean concentration of Cd in plants is higher than those of Cu, Pb and Zn. The concentration of Cd in plant species decreases in the order of Chinese cabbage > red pepper > soybean=sesame > rice stalk > com > rice grain. The biological absorption coefficients (BAC) in plants are in the order of Cd > Zn=Cu > Pb, which suggests that Cd is more bioavailable to plants than Cu, Pb and Zn. From the results of sequential extraction analysis of soils, relatively high proportion of Cu, Pb and Zn are present as residual fractions whereas that of Cd as non-residual fractions. Cadmuim occurs predominantly as exchangeable/water-acid soluble phase in soils, and Cd is more mobile and bioavailable than Cu, Pb and Zn.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.49-59
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• 2004

The concectration and distribution of contaminants obtained from a contaminated land investigation or an environmental geochemistry survey constitutes the basis of a decision-making process on environmental policies or of scientific researches. As the quality of data determines the reliability of the result, the investigation plan should be adjusted according to the purpose of the investigation. In general, the effort to improve the data quality had been focused mainly on the QA/QC procedures in laboratories. The rapid progress of analytical instrument has also contributed toward improving the analytical precision to a sacrificable degree. Nevertheless, in many cases, it is not the analytical precision that needs improvement for the better precision of overall measurement process: it is rather during the sampling process in the field that is responsible for the poor precision. To assess the data quality on a measured value, ISO recommends to provide information on "measurement uncertainty" along with the measured value. The measurement uncertainty in an environmental measurement context can be explained as the statistical number that expresses the degree of the uncertainty stemming from the sampling and analytical procedures. There is a cost involved in order to improve the precision of sampling and analytical methods so as to decrease the degree of measurement uncertainty. The economical point of compromise in an investigation planning can be achieved when the allowable degree of uncertainty has been set before-hand. The investigation can then be planned accordingly not to exceed the uncertainty limit. Furthermore, if the measurement uncertainty estimated from the preliminary investigation can be separated into sampling and analytical uncertainties, it can be used as a criterion where the resources for the investigation should be allotted cost-effectively to reinforce the weakest link of the whole investigation process. This paper aims to present a method of estimating the level of measurement uncertainty of a measured contamination concentration at a site used as an example and to show how the estimated uncertainty can be applied to serve the particular purpose of an investigation.

• 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.

• The Journal of Engineering Geology
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• v.19 no.1
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• pp.89-98
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• 2009

Existence of core stone at the inside of the Rock mass is reacting as unstable element. In particular, in case of the cut slope, even when it is not exposed, slope's discontinuity increases or strength level decreases depending on the difference in the weathering grade when it comes to the core stone, and reacts as an important element of the slope movement such as slope's rock fall or collapse. As for the slope that is subject to study, incision was completed after 20 years or so, and parts of the slope reinforcement was completed, but frequent rock fall occurs despite small amount of rainfall, and permanent stability measures are urgent. Refractional seismic survey and geological survey results were compared and analyzed, and reliability was improved by complementing the two survey methods, and stereo-graphic projection using DIPS program was conducted to analyze the characteristics of oore stone in the weathered soil slope.

• Economic and Environmental Geology
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• v.45 no.2
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• pp.189-194
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• 2012

The consequences of microbe-mineral interaction often resulted in the chemical, structural modification, or both in the biologically induced mineral. It is inevitable to utilize the high powered resolution of electron microscopy to investigate the mechanism of biogenic mineral transformation at nano-scale. The applications of transmission electron microscopy (TEM) capable of electron energy loss spectroscopy (EELS) to the study of microbe-mineral interaction were demonstrated for two examples: 1) biogenic illite formation associated with structural Fe(III) reduction in nontronite by Fereducing bacteria; 2) siderite phase formation induced by microbial Fe(III) reduction in magnetite. In particular, quantification of the changes in Fe-oxidation state at nanoscale is essential to understand the dynamic modification of minerals resulted from microbial Fe reduction. The procedure of EELS acquisition and advantages of EELS techniques were discussed.

• Economic and Environmental Geology
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• v.40 no.6
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• pp.785-795
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• 2007

Recently, the knowledge and use of information production and service in integrated information has been changing from intra-organizational to inter-organizational and even international. In particular, since natural disasters are complexly related, it is increasingly important to use integrated information from related areas in the reduction and prevention of such events. In this study, we suggest strategies for the use of integrated information from natural disasters based on that expanding need. This study analyzes information user surveys, the interrelated information technologies, trends, and case studies to determine user access to the information, the status of the information used, and the supply and distribution of that information. From the survey results, we can draw conclusions about the effectiveness of the strategies of integrated information used in domestic natural disaster information.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.75-80
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• 2016

This study was conducted to evaluate effect of chemical amendments on reducing bioavailable fraction of heavy metals in soil along with ecotoxicological effect on earthworms, Eisenia fetida. Three different chemical amendments, lime (L), steel slag (SS), and acid mine drainage sludge (AMDS), were applied with varied application ratio (1, 3, 5%). Heavy metal contaminated soil was mixed with chemical amedments and earthworms, Eisenia fetida, were cultivated for 28 days. Bioavailable fraction of heavy metals (Cd, Cu, Pb, and Zn) extracted with 0.1N HCl was monitored and also, mortality, growth, and metal concentration in earthworm were assessed. Result showed that all three amendments had high efficiency to reduce bioavailable fraction of heavy metals in soil. In particular, lime showed the highest reduction rate of Cu (63.9-87.7%), Pb (7.90-24.65%), and Zn (40.83-77.60%) among three amendments. No mortality of earthworm was observed during experimental period except 3% and 5% AMDS treatment indicating that application of chemical amendments is safe in terms of ecotoxicological aspect. However, no positive correlation was observed between reduction of bioavaialble fraction of heavy metals in soil and earthworms. Overall, application of chemical amendments in agricultural field can be adapted for reducing bioavailable fraction of heavy metals and detoxification in soil.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.4
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• pp.318-328
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• 1993

A series of long wave measurements was made in the region of Shikotan Island (the South Kuril Islands) during 1990-1992: 7 bottom pressure stations were installed in 5 bays and inlets of Shikotan and 3 precise microbarographs were situated at the shore. The observations were taken in order to monitor tsunami waves, estimate resonance features of coastal topography, and investigate seiche generation mechanism. It was found that forced long waves dominate in the motions with periods exceeding 2 hours, freely propagating long waves prevail at periods of 30-120 min and eigen-oscillations of bays (seiches) are the predominant type of long waves at periods less than 30 min. The Helmholtz mode with period 30 min in Krabovaya Bay and 18.5 min in Malokurilskaya Bay is the most important type of wave motion in the inner Shikotan basins. There is a good correlation between passages of atmospheric disturbances and generation of seiches near the coast of Shikotan Island. In particular, jumps in atmospheric pressure excite seiches in different bays simultaneously, in each one with the corresponding dominant period. The atmospheric spectra were remarkably smooth and stable, and could be described by a $\omega$$^{-2}$26/ power law.

• The Journal of Engineering Geology
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• v.28 no.3
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• pp.349-365
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• 2018

The strain and acoustic emission (AE) signals of Pocheon granite were measured during uniaxial compression tests to investigate microcrack formation and damage. Crack closure, initiation, and damage stresses of each sample were determined through an analysis of the crack volumetric strain and stiffness. The samples experienced four damage stages according to stress levels: stage 1 = crack closure stage; stage 2 = elastic stage; stage 3 = crack initiation stage; stage 4 = crack damage stage. At least 75% of all AE signals occurred in stages 3 and 4, and different AE parameters were detected in the four stress stages. Rise time, count, energy, and duration clearly showed a tendency to gradually increase with the damage stress stage. In particular, the rise time, energy, and duration increased by at least 95% in stage 4 as compared with stage 1. However, the maximum amplitude showed a smaller increase, and the average frequency decreased slightly at higher stages. These results indicate that as the degree of rock damage increases, the crack size grows larger. The crack types corresponding to the AE signals were determined using the relationship between RA (Rise time / Amplitude) values and average frequencies. Tension cracking was dominant in all stress stages. Shear cracking was rare in stages 1 and 2, but increased in stages 3 and 4. These results are consistent with previous studies that reported cracking begins after samples have already been damaged. Our study shows that the state of rock damage can be investigated solely through an analysis of AE parameters when rocks are under compressive stress. As such, this methodology is suitable for understanding and monitoring the stress state of bedrock.

• Journal of the Mineralogical Society of Korea
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• v.24 no.1
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• pp.31-36
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• 2011

Meteorites are extraterrestrial solid rock fragments that fell from the outer space. Investigating mineral magnetic properties of the Meteorites is essential in understanding the evolution of planets and asteroids in the Solar System. In particular, magnetic characterization of magnetic mineral can provide constraints on the progress of differentiation in ancient planetary bodies. In the present study, ratio of thermoremanent magnetization (TRM) over saturation isothermal remanent magnetization (SIRM) was applied to diagnose the magnetic minerals in meteorites and igneous rocks. Distinctive classification of TRM/SIRM suggests that kamacite, tetrataenite, magnetite, and (Cr,Ti)-rich iron oxide are responsible for the magnetization of H5 Richardton, LL6 St. Severin, ALH84001, and DaG476, respectively. The TRM/SIRM ratio could be an efficient tool in identifying magnetic minerals especially when rocks or meteorites contain unstable material under heating.