• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.3
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• pp.212-221
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• 2013

Objectives: Asbestos fibers are accumulated in negative pressure unit (NPU) or vacuum cleaner in asbestos removal. Failure of operation or poor use performance of the NPU or vacuum cleaner causes asbestos fibers to spread in the air. Asbestos contractors should have an NPU fitted with a HEPA , vacuum cleaner, decontamination area, respirators, wetting equipment, and differential pressure manometer to register with the Ministry of Employment and Labor. There should be performance criteria of equipment used in asbestos removal. But there are none such criteria used in asbestos removal. This study was performed to investigate international or national performance criteria of equipment used in asbestos removal. Methods: Regulations, approved code of practice, guidance and national standards of the UK, USA and Korea were reviewed. A survey was done to investigate the requirements for equipment used in asbestos removal in Korea. Results: Air flow of NPUs used in Korea usually covers from$500m^3/h$ to over $3000m^3/h$. Some requirements for NPUs used in Korea were missing compared to the requirements of British standards for NPUs. All NPUs have different missing requirements. The UK also has separate British standard for leak tests for NPUs. Highly hazardous class vacuum cleaners should be used in asbestos removal in the UK. It has national standards on the operation of vacuum cleaners used in asbestos removal. There is only a certification system for less than 2.5kw rated voltage vacuum cleaners for home use in Korea. Powered (-assisted) respirators with mask are recommended in asbestos removal. Type 5 coveralls should be used in asbestos removal in the UK. There are international standards for requirements and leak tests of type 5 coveralls. A manometer for measuring differential pressure is needed in asbestos removal. The manometer's measuring range should cover less than ${\pm}125$ Pa and the gradation of manometer should be less than 2.5 Pa. The definition of decontamination area should be corrected. Installation of airlock and minimum area should be considered in decontamination area. Conclusions: Equipment should be used in asbestos removal proper performance and no leaks. There should be a certification system for equipment used in asbestos removal. This study can help to a certification system for equipment used in asbestos removal in Korea.

• Journal of Radiation Protection and Research
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• v.24 no.2
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• pp.101-108
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• 1999

The influence of the relative humidity, the temperature and the velocity of supply air on evaporation rate has been studied with non-boiling forced evaporation system in order to treat very low level radioactive liquid wastes produced from the decontamination and decommissioning activities. Experimental data on the evaporation rate have been obtained with the divers variables and experimental equation of air velocity was also obtained by the correlation of those data. The decontamination factor of this system was also obtained by the experimental data from a simulated liquid waste containing Cs-137 radio isotope ; $DF=10^4$. Since the commercial system will be operated for the treatment of the very low level radioactive liquid waste produced from decontamination & decommissioning of TRIGA Mark-II&III research reactor, the environmental assessment has been conducted to improve the operational safety. Exposure dose rate for an individual member of general public was assessed, and it showed that it was very lower than individual dose limits. The release of radioactivity of radioisotope material (Cs-137) to the environment was assessed, and result showed that it was $4.637{\times}10^{-14}\;{\mu}Ci/cc$.

• Toxicological Research
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• v.14 no.2
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• pp.217-226
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• 1998

SDK (skin decontamination kit) is new skin decontaminant which is developed by ADD (Agency for defence development). In this study, four-week toxicity of SDK was investigated using beagle dogs and Sprague-Dawley rats. The beagle dogs and Sprague-Dawley rats were dressed topically seven days per week for 28 days, with dosage of 0, 0.25, 0.8 and 1 g/kg/day. respectively. Animals treated with SDK did not cause any death and show any clinical signs. They did not show any significant changes of body weight, feed uptake and water consumption. They were not significantly different from the control group in urinalysis, ocular examination and histopathological examination. In hematological and serum biochemical assay, there were no-dose-defendent changes. Therefore, SDK was not indicated to have any toxic effect in the beagle dogs and Sprague-Dawley rats when it was dressed topically below the dosage 1 g/kg/day for four weeks.

• Toxicological Research
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• v.14 no.2
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• pp.211-216
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• 1998

In order to evaluate the mutagenic potential of SDK(skin decontamination kit) produced by Agency for Defense Development(ADD), were performed Salmonella typhimurium reversion assay, chromosomal aberration test on chinese hamster ovarian cells and in vivo micronucleus assay using mouse bone marrow cells according to the established regulation of Korean Food and Drug Administration. In the reverse mutation test using Salmonella typhimurium TA98, TA100, TA1535 and TA1537 did not in-crease the number of revertant at any of the concentration tested in this study. SDK did not increase the number of cells having structural or numerical chromosome aberration in cytogenetic test. In mouse micronucleus test, no significant increase in the occurrence oj micro nucleated polychromatic erythrocytes were observed in ICR male mice intraperitoneally administered with SDK. These results indicate that SDK has no mutagenic effects under these experimental conditions.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2761-2766
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• 2021

A method for preparing "reagent" for radioactive methyliodide vapors production using an isotopic exchange reaction has been developed. Based on the obtained data of the isotopic exchange efficiency and hydraulic resistance, white fused alumina (700-840 ㎛) was selected as the carrying agent material for "reagent" production. The radioiodine isotopic exchange dependences on such parameters as temperature, gas flow velocity, and the methyliodide concentration in it were determined. Optimal conditions have been selected to achieve 85% of the isotopic exchange rate in 1 h of the experiment. The obtained data allowed to develop an approach to the test of iodine filters for nuclear power plants and to determine their efficiency.

• Biomedical Science Letters
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• v.16 no.3
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• pp.133-138
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• 2010

Despite of the increasing importance of environmental mycobacteria, detection and identification of mycobacteria from environmental sources including water have been fraught with technical difficulties. Although, several protocols to optiruize isolation of mycobacteria from water sources have been reported, standard method has not yet been established. In this study, usefulness of cetylpyridinium chloride (CPC), a cationic quaternary ammonium compound, for the isolation of environmental mycobacteria from diverse water samples was evaluated. For this, water samples from diverse water sources such as effluent water, lake water, and underground water were collected, treated with diverse concentrations of CPC, and plated on the solid agar plates. Subsequently individual colonies grown on the plates were sequence analyzed for identification of each colony. In brief, the results from this study showed that the growth of mycobacteria was enhanced by use of CPC as a pre-treatment reagent to water samples by inhibiting growth of other non-mycobacteria in water. In fact, the effect of CPC to decontaminate non-mycobacteria for isolation of mycobacteria was better than 1~4% of NaOH, which is a routinely used decontaminating reagent widely employed for culturing mycobactera from sputum specimens. Therefore, the results from this study seems to support that the CPC pre-treatment may be useful for isolation of mycobacteria from diverse sources including clinical specimens which are often contaminated with other bacteria.

• Journal of Environmental Impact Assessment
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• v.14 no.4
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• pp.147-155
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• 2005

This study was designed to investigate the effect of plant as a botanical air purification on the indoor pollution by formaldehyde. Three indoor plants such as Dracaena marhginata, Spathiphyllum and Dracaena reflexa, were placed in the artificially contaminated reactor under laboratory condition. Both plant and soil effects on removal of formaldehyde from contaminated indoor air were observed. Reductions in the formaldehyde levels appeared to have been associated with soil medium factors as well as plant factors. The effect of soil on formaldehyde reduction was high in the early stage of the experiment and the results suggest that sorption could be more important factor than microbial degradation in the initial dissipation of contaminants in the soil. It was suggested that the effect of plant on formaldehyde reduction might be related to the plant species, total leaf surface area of plant, degree of contribution of soil medium, and exposed concentration level. The results of this study showed that air purification using plants is an effective means of reduction on indoor formaldehyde level, though, utilization of soil media with high sorption capacity and/or supplementary purifying aids were also suggested when the source is continuous or exposed concentration level is high.

• Economic and Environmental Geology
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• v.32 no.1
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• pp.43-51
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• 1999

In order to remediate hazardous waste site, a process of electrokinetically purging chemicals from saturated soil is examined by laboratory experiments. Electrokinetic soil remediation is one of the most promising soil decontamination processes that habe igh removal efficiency and time-effectiveness in low-permeability soils such as clay. Being combined with several mechanisms-electromigration, elec troosmosis, diffusion and electrolysis of water, electrokinetic soil processing can remove non-polar organics as well as ionic contaminants. The objectives of this study are; 1) the exploration of the feasibility of electrokinetic soil processing on the removal of heavy metals, 2) the investigation of applicability to the tailing-soils in aban doned mining area, 3) the examination of effects of soil pH and conductivity on the transport phenomena of elements in soils, and 4) the investigation of the applicability of the ionexchange membrance to the efficient collection of heavy metals removed from contaminated soils. With the result of this study, it is suggested that the removal efficiency is significantly influenced by applied voltage & current, type of purging solutions, soil pH, permeability and zeta potentials of soil. Although further study should be needed, it is possible to collect removed heavy metals with ion-exchange membrance in cathode compartment.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.5
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• pp.1-9
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• 2005

This study was conducted to investigate the effect of aquatic plant as a botanical air purification on the indoor air pollution by formaldehyde. Three aquatic plants such as Eichhornia crassipes, Cyperus alternifolius, Echinodorus cordifolius, were selected for this study and they were placed in the artificially contaminated chamber under laboratory condition. The results showed that all three plants could remove the formaldehyde from the contaminated air system effectively. Reduction in the formaldehyde levels by Eichhornia crassipes, which is the floating plant, might be associated with the factors of plant and water. Reduction in the formaldehyde levels by Cyperus helferi and Echinodorus cordifolius, which were emergent plant, was due to the complex effect of plant, soil medium and water. In aquatic plant system, dissolution, microbial degradation in rhizosphere, uptake through root and shoot, sorption to soil and shoot, hydrolysis are known as the main mechanisms of water soluble pollutants in the given system. The advantages of indoor air quality control system using aquatic plants can be; 1) various purifying mechanisms than foliage plants, 2) effective for decontamination of water soluble pollutants; 3) easy for maintenance; 4) diverse application potential. Therefore it was suggested from the results that indoor air control system of aquatic plants should be more effective for reduction of indoor air pollutants.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.127-137
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• 2018

Radioactive contamination has become an important environmental concern after the accident occurred in Fukushima Daiichi Nuclear Power Plants. $^{134}Cs$ and $^{137}Cs$ are the major fission products and they are main problems in radioactive contamination. Huge amounts of Cs were released during the Fukushima Daiichi Nuclear Power Plants accident and as a result of this incident, many researchers focused on the development of adsorbents for decontamination of radiotoxic cesium. This review will critically evaluate recent advances in the preparation of Prussian blue and its analogue compounds, which are promising materials for cesium removal. Furthermore, this review will discuss recent studies on the cesium adsorption using different types of clay and clay based adsorbents and summarize various types of newly developed Cs adsorbents reported in recent years.