• Journal of Radiation Protection and Research
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• v.41 no.2
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• pp.173-178
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• 2016

Background: In situ gamma spectrometry has been used to measure environmental radiation, assumptions are usually made about the depth distribution of the radionuclides of interest in the soil. The main limitation of in situ gamma spectrometry lies in determining the depth distribution of radionuclides. The objective of this study is to develop a method for subsurface characterization by in situ measurement. Materials and Methods: The peak to valley method based on the ratio of counting rate between the photoelectric peak and Compton region was applied to identify the depth distribution. The peak to valley method could be applied to establish the relation between the spectrally derived coefficients (Q) with relaxation mass per unit area (${\beta}$) for various depth distribution in soil. The in situ measurement results were verified by MCNP simulation and calculated correlation equation. In order to compare the depth distributions and contamination levels in decommissioning KRR site, in situ measurement and sampling results were compared. Results and Discussion: The in situ measurement results and MCNP simulation results show a good correlation for laboratory measurement. The simulation relationship between Q and source burial for the source layers have exponential relationship for a variety depth distributions. We applied the peak to valley method to contaminated decommissioning KRR site to determine a depth distribution and initial activity without sampling. The observed results has a good correlation, relative error between in situ measurement with sampling result is around 7% for depth distribution and 4% for initial activity. Conclusion: In this study, the vertical activity distribution and initial activity of $^{137}Cs$ could be identifying directly through in situ measurement. Therefore, the peak to valley method demonstrated good potential for assessment of the residual radioactivity for site remediation in decommissioning and contaminated site.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.163-174
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• 1999

This paper presents a case history of remedial action adopted for contaminated groundwater in a landfill. The objectives of the projects are : (1) to effectively confine contaminated groundwater with an economically reasonable means, (2) to prevent further contamination of soil by collecting and treat the contaminant. and (3) to assure the environmental safety of the landfill during its operating period. Reported are the process from site investigation, through design and construction of an appropriate remedial action, to the monitoring of the selected confinement system. In view of the results of site investigation, deep soil mixing cutoff wall using the DMW(deep soil mixing cutoff wall) method and specially produced HEC soil stabilizer were used for the construction of deep soil mixing cutoff wall. For rock foundation with sever fractures, chemical grout curtain with urethane was installed. The monitoring results to date indicate that the selected vertical barrier performed satisfactorily.

• Journal of Soil and Groundwater Environment
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• v.19 no.6
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• pp.18-23
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• 2014

The BTEX contamination of soil around gas station in Korea was investigated in 53 gas stations in 2013 by official test method on soil pollution. Each gas station was divided into oil tank area, line area, and surrounding area. The concentration of BTEX in 1066 sites of 53 gas stations was N.D.~ 3437.36 mg/kg. The order of average concentration for area was as follows: line area ($20.91{\pm}144.79mg/kg$) > tank area ($15.11{\pm}110.08mg/kg$) > surrounding area ($10.79{\pm}111.40mg/kg$). It was the number of sampling site exceeding regulatory levels at surrounding area the most at all. The average concentration of xylene was the highest, while that of ethylbenzene was the lowest.

• Journal of Soil and Groundwater Environment
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• v.7 no.2
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• pp.3-11
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• 2002

The objective of this study was to survey the oil contamination around the Mountain Baegun at Uiwang city to obtain the preliminary data for bioremediation. For measuring the oil concentrations and physical properties from soil, we analyzed BTEX. TPH and pH, organic content, water content, pormeability coefficient, gravity, porosity and used the purge & trap method for analyzing BTEX. Using the Accelerated Solvent Extractor, we pretreated the samples and then analyzed TPH using GC-FID as soon as possible. From the analysis results, maximum concentration of TPH was 24.773mg/kg and BTEX was 101.7mg/kg. The results of TPH at the Mountain Baegun were higher than the enforcement standard of soil contamination(Korea) and the BTEX concentrations were also higher than the advisory standard of soil contamination(Korea). From these results, the Mountain Baegun may requires to remedy the oil-contaminated soil. In addition, we performed the field bioremediation test for five weeks at the Mountain Baegun using the microbial additives that were developed by our laboratory. From the results of the field test, we could find the about 95% of the oil was removed from the contaminated soil in five weeks. So we consider that it is the one of the useful solutions to remedy the oil-polluted site.

• Journal of the Korean Society of Groundwater Environment
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• v.3 no.2
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• pp.70-79
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• 1996

The Friar Tuck Abandoned Coal Mine site is one of the most complexly disturbed areas in the midwestern United States. The deposits of gob and tailings contain high concentrations of pyrite, whose oxidation contributes to the acidification of soil and water and prevents the growth of vegetation. In an effort to quantitatively evaluate the effects of reclamation techniques, detailed monitoring program was performed. Water samples were collected from surface water, groundwater, and pore water from the unsaturated zone during a period of five years. According to the results, The spoil deposits are a relatively minor source of contamination and gob piles are the source of severe contamination to surface water and groundwater. But, loess and till beneath the gob piles effectively prevent the contaminated water migration from the source. Surface layers of the gob piles and the tailing deposits are less toxic than the interior of the deposits as a consequence of weathering over several decades. Acid mine drainage is in a post-peak stage and acid formation potential is probably situated in the unsaturated zone of refuse.

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.525-539
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• 2020

A site containing buried solid waste and treated water and oil storage containers from a leather manufacturing plant was studied through soil and groundwater pollution and electrical resistivity surveys with the aim of identifying areas polluted by leachate generated by landfilling with leather waste and leakage wastewater. It was found that TPH and Zn exceeded environmental standards for soil pollution and, for leachate and groundwater, Cr(VI) concentrations exceeded standard levels for groundwater quality. An electrical resistivity survey was used to elucidate soil and groundwater pollution characteristics and diffusion pathways. Ten survey lines were set up with an electrode spacing of 5 m in a dipole-dipole array. The hydraulic characteristics of soil determined by groundwater contamination surveys matched well the low-resistivity-anomaly zones. Electrical resistivity surveys of areas containing contaminated soil and groundwater that have irregular strata due to waste reclamation are thus useful in highlighting vertical and horizontal pollutant diffusion pathways and in monitoring contaminated and potentially contaminated areas.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.35-48
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• 2004

This paper provides a comprehensive overview of geochemical approaches for investigating and assessing heavy metal contamination in abandoned mine sites. Major sources of contaminants at the abandoned mine sites are mine water, waste rocks, tailings, and chemicals used in beneficiation and mineral processing. Soil, sediment, surface and ground water, and ecological system can be contaminated by heavy metals, which are transported due to erosion of mine waste piles, discharge of acid mine drainage and processed water, and dispersion of dust from waste rocks and tailings. The abandoned mine sites should be characterized using various methods including chemical analysis, mineralogical analysis, acid generation prediction tests, leaching/extraction tests, and field tests. Potential and practical environmental impacts from the abandoned mines should be assessed based on the site characterization.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.229-241
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• 2008

In order to investigate stabilization effect on As-contaminated soils treated by zero-valent iron(ZVI) and industrial by-products, batch tests and column tests were carried out with As-contaminated soils collected from farmland around the abandoned mine site. In batch tests, ZVI and industrial by-products(blast furnace slag, steel refining slag and oyster shell powder) were used as treatment materials to reduce As. Industrial by-products were mixed with As-contaminated soils, in the ratio of 1%, 3%, 5% and 7% on the weight base of dried soil. After incubation, all samples showed the reduction of As concentration and it was expected that ZVI and steel refining slag were effective treatment materials to remove As among treatment materials used in batch test. In column tests, columns were made by acrylic with the dimension of diameter=10cm, height=100cm, thickness=1cm and these columns were filled with untreated soils and treated soils mixed with ZVI and steel refining slag(mixing ratio=3%). Distilled water was discharged into the columns with the velocity of 1 pore-volume/day. During test, pH, EC, Eh and As concentration were measured in the regular term(1 pore-volume). As a result, ZVI and steel refining slag were shown 93%, 62% reduction of As concentration respectively by comparison with untreated soils. Therefore, if ZVI and steel refining slag are used as treatment materials in As-contaminated soils, it is expected that the As concentration in soils is reduced effectively.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.10a
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• pp.89-110
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• 2003

The limitations of conventional soil and groundwater contamination remediation technologies have motivated a search for innovative technologies; particularly in situ technologies that do not require extraction of contaminants from the subsurface. All engineered in situ remediation systems require that the contaminant be mixed with a remedial compound. Horizontal flow treatment wells (HFTWs), an innovative technology that consists of a pair of dual-screened treatment wells, were used at a trichloroethylene (TCE) contaminated site to efficiently achieve this mixing of contaminant and remedial compound in order to effect in situ bioremediation (McCarty et al., 1998). In this paper, the potential of HFTWs to treat chlorinated aliphatic hydrocarbons (CAHs) as well as other soil and groundwater contaminants of concern, such as nitroaromatic compounds (NACs), perchlorate, and methyl-tert-butyl ether (MTBE), is examined. Through a combination of laboratory studies, model analyses, and field evaluations, the effectiveness of this innovative technology to manage these contaminants is investigated.

• Environmental Engineering Research
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• v.23 no.4
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• pp.420-429
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• 2018

Soil stabilization is a soil remediation technique that reduces the mobility of heavy metals in soils. Although it is a well-established technique, it is nonetheless essential to perform a follow-up chemical assessment via a leaching test to evaluate the immobilization of heavy metals in the soil matrix. Unfortunately, a standard chemical assessment is not sufficient for evaluation of the biological functional state of stabilized soils slated for agricultural use. Therefore, it is useful to employ a pyrosequencing-based microbial community analysis for the purpose. In this study, a recently stabilized site in the proximity of an exhausted mine was analyzed for bacterial diversity, richness, and relative abundance as well as the effect of environmental factors. Based on the Shannon and Chao1 indices and rarefaction curves, the results showed that the stabilized layer exhibited lower bacterial diversity than control soils. The prevalence of dominant bacterial populations was examined in a hierarchical manner. Relatively high abundances of Proteobacteria and Methylobacter tundripaludum were observed in the stabilized soil. In particular, there was substantial abundance of the Methylobacter genus, which is known for its association with heavy metal contamination. The study demonstrated the efficacy of (micro)biological assessment for aiding in the understanding and post-management of stabilized soils.