• Korean Journal of Environmental Agriculture
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• v.38 no.1
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• pp.54-60
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• 2019

BACKGROUND: Hydrogen fluoride is one of the 97 accident preparedness substances regulated by the Ministry of Environment (Republic of Korea) and chemical accidents should be managed centrally due to continual occurrence. Especially, hydrogen fluoride has a characteristic of rapid diffusion and very toxic when leaking into the environment. Therefore, it is important to predict the impact range quickly and to evaluate the residual contamination immediately to minimize the human and environmental damages. METHODS AND RESULTS: In order to estimate the accident impact range, the off-site consequence analysis (OCA) was performed to the worst and alternative scenarios. Also, in order to evaluate the residual contamination of hydrogen fluoride in crop, the samples in accident site were collected from 15-divided regions (East direction from accident sites based on the main wind direction), and the concentration was measured by fluoride ($F^-$) ion-selective electrode potentiometer (ISE). As a result of the OCA, the affected distance by the worst scenario was estimated to be >10 km from the accident site and the range by the alternative scenario was estimated to be about 1.9 km. The residual contamination of hydrogen fluoride was highest in the samples near the site of the accident (E-1, 276.82 mg/kg) and tended to decrease as it moved eastward. Meanwhile, the concentrations from SE and NE (4.96~28.98 mg/kg) tended to be lower than the samples near the accident site. As a result, the concentration of hydrogen fluoride was reduced to a low concentration within 2 km from the accident site (<5 mg/kg), and the actual damage range was estimated to be around 2.2 km. Therefore, it is suggested that the results are similar to those of alternative accident scenarios calculated by OCA (about 1.9 km). CONCLUSION: It is difficult to estimate the chemical accident-affecting range/region by the OCA evaluation, because it is not possible to input all physicochemical parameters. However simultaneous measurement of the residual contamination in the environment will be very helpful in determining the diffusion range of actual chemical accident.

• Journal of Soil and Groundwater Environment
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• v.18 no.3
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• pp.119-133
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• 2013

In the present study, several groundwater vulnerability assessment methods were applied to an agricultural area of Gumma in Korea. For the groundwater intrinsic vulnerability assessment, the performance of DRASTIC, SINTACS and GOD models was compared and an ensemble approach was suggested. M-DRASTIC and multi-linear regression (MLR) models were applied for the groundwater specific vulnerability assessment to nitrate of the study site. The correlation coefficient between the nitrate concentration and M-DRASTIC index was as low as 0.24. The result of the MLR model showed that the correlation coefficient is 0.62 and the areal extents of livestock farming and upland field are most influential factors for the nitrate contamination of groundwater in the study site.

• Journal of Environmental Science International
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• v.17 no.1
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• pp.119-128
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• 2008

Laboratory analytical results of 22 sets of hydrophobic adsorbent coils containing surface soil-vapor and two soil samples collected by conventional intrusive method from each boring location at two active dry cleaning facilities in the State of Illinois, U.S.A, were presented to evaluate the performance of soil-vapor survey. The most critical factor to determine the effectiveness of soil-vapor survey is the distance from the soil-vapor sampling device to the actual contamination, which is a function of soil porosity, permeability, primary lithology, and other geological and hydrogeological site-specific parameters. Also this factor can be affected by the history of contaminant-generating operations. The laboratory analytical results in this study showed longer dry cleaning operation history (i.e., 50 years) and presence of fine sand at the beneath Site B allow the contaminants to migrate farther and deeper over a fixed time compared to Site A(i.e., 35 years and silty clay) so that the soil-vapor survey is not likely the most effective environmental site investigation method alone for Site B. However, for Site A, the soil-vapor survey successfully screened the site to identify the location reporting the highest soil concentration of chlorinated solvents.

• Journal of Environmental Science International
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• v.13 no.5
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• pp.479-488
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• 2004

Five sediment cores from the tidal flat of artificial Lake Shihwa are analyzed in terms of sedimentology and geochemistry to evaluate the heavy metal contamination and redox condition of surficial sediment following the Shihwa seawall construction. The variability of concentrations of various elements depends on the depositional environment, and reflects the various redox conditions and sediment provenances. The amounts of Ti and Al and their ratio of Ti/ Al with respect to Li clearly indicate that there is an anthropogenic contribution to the surficial sediment. The high concentrations of heavy metals suggest an anthropogenic contribution at ST. 34 and ST. 22. Concentrations of most elements (Cr, Cu, Zn and Pb) are higher near the Shihwa-Banwol industrial complex than in the central part of Lake Shihwa. Concentrations of heavy metal in surficial sediment near the Shihwa-Banwol industrial complex are two to eight times higher than in the center of Lake Shihwa. Enrichment factors (EF), which are normalized by the unpolluted shale, suggests a significant metallic contamination near the Shihwa-Banwol industrial complex (SBIC). The redox condition is divided into two anoxic and mixed oxi $c_oxic zones based on the carbon:sulfur (C/S) ratios of organic matter and elemental relationships. Correlations among geochemical elements Mn, U and Mo are significantly different from site to site, and may therefore be an indicator of the spatial redox condition. Controlling factors for switching anoxic/oxic conditions are thought to be water depth and the differences in industrial effluent supply. The variations of the Cu/Mn ratio in the sediments confirms above mentioned spatial differences of a redox condition in part, and therefore shows a location-dependence redox condition in sediments at four other sites. The redox condition of the surficial sediment characteristics of the Shihwa Lake are controlled by its geographic location and water depth.th.

• Biomedical Science Letters
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• v.8 no.2
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• pp.63-69
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• 2002

This study was performed to investigate the effectiveness of the aspiration trap method for collection of sputum by comparing with the conventional method which was collecting specimens at canular cap swab. In this study, the author tested by two methods to collect specimens from 46 patients who were cared with tracheostomy and intubation at the intensive care unit of an university hospital in Pusan, and investigated the incidence of the lower respiratory tract infection, the consistency between the two methods, the level of specimen contamination. Major results were as follows: Among the patients, 35 were cared with tracheostomy and 11 were cared with intubation. In clinical diagnosis we were classified the subjects in to two group, 17 of pneumonia group and 29 of non-pneumonia group. A total of 247 strains were isolated. Among them, most three strains were Serratia marcescens (62 strains; 25.1%), Pseudomonas aeruginosa (52 strains; 21.1%), and Acinetobacter baumannii (19 strains; 7.8%). Out of total, 188 (76.1%) strains were Gram negative bacilli. The isolated strains by the aspiration trap method were the average 2.1 strains, but by the canular cap swab method were 1.6 strains. In spite of the high contaminated possibility from the incision site and the oral cavity swab, the low isolated rates of the canular cap may be the dried environment of the canular of cap area. But the contamination rates were 57.2% of the canular cap, 51.5% of the oral swab and 50.5% of the incision site swab, respectively. The consistency of predominant microorganisms according to collection method were 86.7% of aspiration, 78.3% of canular, 74.3% of incision, and 63.6% of oral. In conclusion, the aspiration trap method fur the sputum collection from the patients with intubation of tracheostomy showed the lower contamination rate of the specimens and it was helpful for rapid, accurated interpretation of the lower respiratory tract infection and hospital infection.

• Analytical Science and Technology
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• v.16 no.3
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• pp.232-239
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• 2003

The river sediments were collected from 4 points of Seoknam river, one point of Miho river and one point of the joining area of two rivers. For preparation of sample, three sediment samples were collected for the surface, middle and lower part of the sediment at each sampling point. The elemental concentrations were analyzed by neutron activation analysis using HANARO research reactor at Korea Atomic Energy Research Institute, and the concentrations of 30 elements were determined by the relative method using standard reference material of NIST. As a result of analysis, it was found that when the examination and prediction of contamination distribution about the site where the contamination site of river is connected to the lower river is done, the specific gravity of elements which is contained in the sediment and the speed of a current of river should be considered and also found that when the samples for concentration analysis in the river sediments are collected, for the establishment of regional representatives in samples, the range of sampling depth should be determined considering the specific gravity of elements and the speed of a current.

• Journal of Soil and Groundwater Environment
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• v.25 no.2_spc
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• pp.1-15
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• 2020

Monitoring and assessing terminal electron accepting processes (TEAPs) are one of the most important steps to remediate contaminated sites via various in-situ techniques. TEAPs are a part of the microbial respiration reactions. Microorganisms gain energy from these reactions and reduces pollutants. Monitoring TEAPs enables us to predict degradability of contaminants and degradation rates. In many countries, TEAPs have been used for characterization of field sites and management of groundwater wells. For instance, US Environmental Protection Agency (EPA) provided strategies for groundwater quality and well management by applying TEAPs monitoring. Denmark has also constructed TEAPs map of local unit area to develop effective groundwater managing system, particularly to predict and assess nitrogen contamination. In case of Korea, although detailed soil survey and groundwater contamination assessment have been employed, site investigation guidelines using TEAPs have not been established yet. To better define TEAPs in subsurface environments, multiple indicators including ion concentrations, isotope compositions and contaminant degradation byproducts must be assessed. Furthermore, dissolved hydrogen concentrations are regarded as significant evidence of TEAPs occurring in subsurface environment. This review study introduces optimal sampling techniques of groundwater and dissolved hydrogen, and further discuss how to assess TEAPs in contaminated subsurface environments according to several contamination scenarios.

• Journal of Soil and Groundwater Environment
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• v.18 no.2
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• pp.19-26
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• 2013

This study developed the classification of National Soil Quality Monitoring Network (NSQM) and its site selection criteria to meet the recently established purposes of the NSQM. The NSQM were suggested by this study to classify into the six-purposes site groups from the current classification of land uses. The six purposes site groups were 1) intensive observation sites, 2) contaminant loading sites, 3) human activity sites, 4) background sites, 5) river soil sites, and 6) sites near the groundwater quality monitoring wells. Furthermore, this study developed the site selection criteria of NSQM utilizing the accumulated NSQM data, road traffic data, chemical emission data, census, soil information, and the literature related to soil quality variation due to contaminant loads. For selecting suitable sites for NSQM, this study used road traffic, chemical emission, the distance from the contaminant sources, and population information as specific criteria. The suggested site classification and criteria were appled for the current 100 NSQM sites for evaluation. Forty sites were met to the criteria suggested by this study, but sixty sites were not met to the criteria. However, some of the sixty sites also included the obscure sites that their addresses were not apparent to find them.

• Journal of Environmental Health Sciences
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• v.46 no.5
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• pp.548-554
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• 2020

Objectives: This study is to examine the polyvinyl chloride (PVC) materials in elementary school classrooms and libraries in Seoul, and to investigate phthalate contamination in indoor dust. Methods: PVC material was identified for building materials and furniture using portable x-ray fluorescence (XRF). Phthalates in dust samples (n=19) were extracted by ultrasonic extraction using cyclohexane and analyzed by GC-MS. Results: Diethyl phthalate (DEP), di-n-butyl phthalate (DBP), and Bis (2-ethylhexyl) phthalate (DEHP) were found in all collected dust samples (n=19), and diisonyl phthalate (DINP) was detected in all except for one sample (n=18). The concentration of DEHP (median: 2190 mg/kg) and DINP (2960 mg/kg) were higher than other compounds, suggesting that there are many products in the school that used these compounds. When comparing the phthalate concentration in the classroom (n=11) and library dust (n=8), the total concentration in the classroom (median: 10000 mg/kg) was higher than that in the library (8030 mg/kg). DEHP was the dominant compound in the library. The library is relatively more equipped with PVC furniture (n=83) and most floors are also identified as PVC material, suggesting that floors and furniture made of PVC materials are main sources of DEHP contamination. Conclusions: This study is a pilot survey for investigating phthalate contamination in elementary schools. As a result of the survey, phthalate contamination in elementary school was confirmed. However, further study requires risk assessment of children through analysis of phthalate metabolites in children based on sufficient number of samples and information about the site.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.1
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• pp.1-7
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• 2013

This study was on leaching test(KSLT, TCLP) of the aggregate for the products(RA-1) and for the site(RA-2) to evaluate the characteristics of contaminants and the possibility of contamination arising from the aggregate. On the basis pH, conductivity and heavy metal contents in the aggregate, RA-1 indicated higher than RA-2. As a result of the leaching test, the pollutants were eluted from the aggregate increased as the particle size of the aggregate was smaller. The pH in the aggregate had a strong alkali by a pH value of 9.0~12.3, the conductivity was higher in less than 10mm RA-1 due to the leaching of dissolved inorganic ions. The heavy metals satisfied the leaching standards of KSLT and less 10% was eluted from the aggregate. As a result of evaluating water pollution possibility of the aggregate, the pH displayed in items with a very high possibility of contamination, conductivity and turbidity did in item with a low possibility of contamination and on the other hand the heavy metals did in item with a very low possibility of contamination.