• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.18 no.1
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• pp.20-31
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• 2008

A respirator is useful to protect a worker from the harmful gases and vapors in the workplace, and the evaluation of respirator cartridge service life is important for the worker's health and safety. The performance of cartridge is effected by several factors such as concentration of gas and vapor, humidity, temperature, adsorbents and cartridge packing density. Adsorption model was applied to both sampling tube and respirator cartridge to predict the service life for organic vapors. The variables of the adsorption model were measured from the experiment with the sampling tube, and it was used to predict the service life of respirator cartridge. In the experiment, we used carbon tetrachloride as a organic vapor and activated carbon take out respirator cartridge as activated carbon. As a result, it was possible to predict the service life of respirator cartridge and predicted service life was quite correct. Breakthrough time decreased with increase of CCl4 concentration. In case of sampling tube, adsorbed amount of CCl4 was larger than respirator cartridge due to linear velocity. Also, rate constant of sampling tube was larger than respirator cartridge, because of, effect of flow rate, packing density. In the prediction of service life of respirator cartridge by using sampling tube, the time required for 50% contaminant breakthrough(${\tau}$) is more effective than the rate constant(k').

• Fashion & Textile Research Journal
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• v.5 no.4
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• pp.395-398
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• 2003

In this study, we measured the antibacterial activities, deodorization, UV cut ability, whiteness and SEM, according to the size($5{\mu}m$, $15{\mu}m$) of $TiO_2$, concentration(3%, 5%, 10%) and dipping temperature($50^{\circ}C$, $70^{\circ}C$) with using anatase type of $TiO_2$ photocatalyst. Photocatalyst is the substance which carries out functions, such as decomposition, removal, deodorization, antibacterial, etc. of a contaminant, in a place with light based on an oxidation-reduction reaction. The results of this study were as follow. Antibacterial activities are increased with increasing of the $TiO_2$'s concentration, and $TiO_2$ has high antibacterial activities for Staphylococcus aureus but it has low antibacterial activities for Klebsiella pneumoniae. The deodorization and UV cut ability is very good, therefore be able to get good effects with using only 3% of $TiO_2$. Every effects are increased by using small size of $TiO_2$ and high dipping temperature.

• Journal of Korean Society on Water Environment
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• v.27 no.1
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• pp.120-128
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• 2011

Korea Groundwater Quality Monitoring Network is a database of annual groundwater quality survey results to prevent groundwater pollution. We estimated contamination index (CI) values for each type of land use, and analyzed temporal trends of pollutant concentration data in the Groundwater Quality Monitoring Network from 2001 to 2009. Among the pollutants considered in the database, the concentrations of nitrate and chloride were higher than their standards. In the case of nitrate, recreation parks, golf courses and general waste dumping regions showed increasing trends according to linear regression analysis, whereas industrial complexes and residential regions of urgan and recreation parks showed increasing trends in the chloride concentration data. According to multiple variable linear regression analysis, EC, pH and topography were major factors influencing CI values. These results suggest that groundwater with a high CI value and increasing trend is vulnerable for potential contamination, which requires more careful groundwater pollution control.

• Journal of Soil and Groundwater Environment
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• v.27 no.3
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• pp.1-10
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• 2022

Most wells developed in Jeju island before the enactment of the Groundwater Management Ordinance in 2002 are vulnerable to aquifer contamination due to inflow of upper groundwater having the high concentration of nitrate nitrogen, likely due to incomplete grouting in upper section of the wells. Although these wells require entire reinstallation, it is often necessary to rehabilitate the existing wells due to various constraints. Therefore, to identified the inflow section of contaminants, the thermal level sensor (TLS) technique was firstly applied for three wells, which enables to monitor temperature variations in every 50 cm depth. Then, the grouting material was injected to the upper section to prevent the inflow of upper contaminated groundwater into the entire aquifer. By applying TLS technique, it was found that the temperature deviations in the upper groundwater inflow section decreased sharply. Moreover, both the change in the concentration of nitrate nitrogen in the rainy/dry seasons and the average concentrations were found to decrease rapidly after grouting material injection. Consequently, the application of TLS proposed in the study turned out to be appropriate to prevent aquifer contamination.

• Journal of Soil and Groundwater Environment
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• v.29 no.3
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• pp.14-22
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• 2024

This study established risk-based fluoride soil contamination standards according to the Korean Soil Contaminant Risk Assessment Guidelines (SRAG). Ten exposure scenarios were evaluated, broadly categorized into Scenario 1, which used the default parameters from the current SRAG, and Scenario 2, which used the latest exposure factors and bio-concentration factors. Fluoride soil standards corresponding to a total hazard index (HI) of 1.0 were determined for each scenario. For children in agricultural areas, the derived risk-based soil fluoride standard was 70 mg/kg for Scenario 1 and 27 mg/kg for Scenario 2. In industrial areas, the risk-based fluoride soil standard was 2200 mg/kg in Scenario 1 and 2300 mg/kg in Scenario 2. This study clearly demonstrated that the crop ingestion exposure pathway exerted predominent influence on the estimated human health risk standards. Additionally, using the Added Risk Approach and considering soil background concentrations, the total fluoride soil standards for residential areas ranged from 232 mg/kg to 444 mg/kg, while the standards for industrial areas ranged from 2405 mg/kg to 2674 mg/kg.

• Journal of Environmental Health Sciences
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• v.31 no.5 s.86
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• pp.349-359
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• 2005

In this study, we focused on the geographical and the meterological conditions, the atmospheric examination, the soil contents and compositions in order to establish cultural properties conservation plan in Gyeongju and its surroundings. Also, the transport route with environmental contaminants in Ulsan and Pohang was examined. The results could be summarized as follows ; Air pollutant and environmental contaminant was transported by two types of winds. One is induced by local winds, the other is induced by synoptic winds. Air contaminant transported from coastal regions to inland regions were associated with wind velocity. Gyeongju had good atmospheric conditions, i.e. $SO_2\;0.009{\sim}0.011ppm,\;CO\;0.6{\sim}0.8ppm,\;NO_2\;0.015{\sim}0.020ppm,\;O_3\;0.017{\sim}0.032ppm,\;PM_{10}\;46{\sim}62{\mu}g/m^3\;and\;Pb\;0.034{\sim}0.060{\mu}g/m^3$, which was below environmental air qualify standards and was little lower than those of Pohang and Ulsan. However, Ulsan and Pohang city are located on south-east coast and have many industrial facilities. Hence, air pollution problems become serious issues in Ulsan, Pohang, Busan, Daegu and other cities due to the emission of air pollutants from the various industrial facilities, incinerator and power plants, etc. The soil of Gyeongju had heavy metals conditions, i.e. $Cd\;0.01{\sim}0.08mg/kg,\;Cu\;N.D{\sim}2.39mg/kg,\;As\;N.D{\sim}0.07mg/kg,\;Hg\;N.D{\sim}0.15mg/kg,\;Pb\;0.49{\sim}1.39mg/kg,\;Cr^{+6}\;0.02{\sim}0.42mg/kg,\;Fe\;0.74{\sim}1.55mg/kg,\;Mn\;0.11{\sim}0.49mg/kg\;and\;Zn\;1.11{\sim}3.56mg/kg$. However, pH value of soil had range of $4.12{\sim}7.45$. The results showed that high pH concentration of soil could occur due to air pollution diffusion and environmental contaminant transport at Ulsan and Pohang city.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.202-210
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• 2005

In this study, the fly ash was employed as a possible alternative to the bentonite for its high sorption capacity against cationic heavy metal. To consider the constituents of barrier possibly used, the specimens were mixed with different material contents (fly ash : weathered soil : bentonite), then sorption test was performed. Also the specimens were molded on the wet side of optimum moisture contents like mixing ratio of sorption test and their hydraulic conductivities were measured in flexible-wall permeameters. And to confirm the effect of dissolved cations, the hydraulic conductivity tests were repeated by converting the permeant liquids from water to $Cd^{2+}$ solution. Finally, the Cd-concentration at the effluent was analyzed for 500hrs to compare the effectiveness of each specimen in contaminant retardation. Test results showed that the more the ratio of fly ash increase, the more Kd value increase, and the hydraulic conductivity of weathered soil/bentonite (95:5) mixture was the lowest $(2.9*10^{-8}cm/sec)$, and specimens made of fly ash and fly ash/weathered soil mixtures showed similar hydraulic conductivity. Although the permeant liquid was changed from water to $Cd^{2+}$ solution, the hydraulic conductivity of all specimens except for weathered soil maintained similarly like before. Consequently, the initial breakthrough point of Cd in weathered soil specimen was observed at about 5hrs after the test started while that of fly ash specimens was not observed during the whole test period of 500hrs. The results implied that fly ash had a sufficient retardation capacity against contaminant transport possibly by its high sorption capacity although it showed little effect on the reduction of hydraulic conductivity. Based on the test results, it could be concluded that the fly ash can be possibly used as a suitable barrier material in containment system to attenuate the contaminant transport for its high retardation capacity and for the low cost.

• Journal of Forest and Environmental Science
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• v.24 no.2
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• pp.61-68
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• 2008

Acrylamide is present as a contaminant in heated food products, predominantly from the precursor asparagine. Nonanchored inter simple sequence repeats (ISSRs) are arbitrary multiloci markers produced by PCR amplification with a microsatellite primer. In order to assess the feasibility of microsatellite primers as markers for DNA damage, the study was conducted on common bean (Phaseolus vulgaris L.) exposed to different concentrations of acrylamide. Polymorphisms were abundant among plant samples treated with acrylamide in comparison to control (untreated one) tested with 4- tri-nucleotide, 2 tetra-nucleotide, and 3- dinucelotide primers. The primer (CCG)4 was the best tested primer to generate polymorphism between the DNA of plants treated or not by acrylamide. Polymorphisms became evident as the presence and absence of DNA fragments in treated samples compared with the untreated one. The highest number of DNA variation on ISSR patterns was observed at the micromollar concentrations of acrylamide. Acrylamide was able to induce DNA damage in non concentration-dependent manner with effectiveness at micromollar concentrations. This study demonstrated that ISSR markers can be highly reliable for identification of DNA damage induced by acrylamide.

• Journal of environmental and Sanitary engineering
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• v.18 no.4
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• pp.36-44
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• 2003

The cement-based system among S/S(Solidification/Stabilization) is widely used to treat hazardous wastes. In this study, tannery sludge was solidified to evaluate the stabilization effects of using admixtures in the cement-based S/S. Fly ash as substitute also used to increase the strength of the S/S of hazardous waste. The compressive strength measurement and leaching experiment of chromium metal of solidified mortar were carried out to compare and evaluate the physical and chemical characteristics of solidified hazardous waste sludge. From the result of this study, there was increased of compressive strength by using AEW-3(early-hardening AE water reducing agent), and leaching concentration of chromium became low enough to satisfy the regulatory criteria. The successful solidification for the organic contaminant and heavy metal in hazardous waste should enable to treat by cement-based system using early-hardening AE water reducing admixture and fly ash as substituted cement.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.309-312
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• 1999

In recent years there has been a steady increase in geoenvironmental engineering projects where geotechnical engineering has been combined with environmental concerns. Many of these projects involve some investigation on contaminant and leachate flume in the ground and landfill. In this study, investigation on leachate around the waste landfill was carried out to detect the leaked and contaminated area. Many techniques such as geophysical, drilling and sampling method were applied. As a result of this study, the concentration of leachate and the point of leachate leaking around landfill were found out, and countermeasures for cut-off of leachate flow from landfill were investigated.