• 동아시아식생활학회지
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• 제7권1호
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• pp.41-46
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• 1997

Diet is generally accepted as one of the important factors in human cancer development. Ethyl carbamate has been associated with cancer for several decades and mainly found in the fermented beverages and foodstuff. The relationship between ethyl carbamate and the human health cannot be ignored especially in the areas where fermented foods consists of regular food consumption. To investigate the ethyl carbamate exposure level in Korean population, commercial fermented food samples were collected form local markets I Seoul area and home-made varieties were collected throughout the country. Following partial purification the concentration of ethyl carbamete was determined by GC/ MS. The concentration of ethyl carbamate ranged to 70 ppb in soysauce, to 10 ppb in soybean paste, and to 5 ppb in vinegars. Korean traditional alcoholic beverages showed small amount of ethyl carbamate. The estimated daily exposure of Korean population was 0~1900ng/day. It would be prudent to put efforts to minimize the formation of ethyl carbamate since the risk from the higher range exposure cannot be ignored.

• 한국환경보건학회지
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• 제6권1호
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• pp.10-21
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• 1979

In preventing the infection of Clonorchis sinensis, there is one way in which life cycle of Clonorchis sinensis is cut off by eradicating the first intermediate host viz Parafossarulus manchuoricus, with molluscicides or insecticides. This survey was carried out in order to evaluating the molluscicidal effect of several insecticides upon P. manchauricus. In this survey, diazinon, heptachlor, E.P.N., E.M., and malathion was applied as molluscidies. Those insecticides had been generaly used in farming area. The results are summarized as follows. 1) In molluscicidal effect, E.M. showed the higher molluscicidal effect than any other insecticides in all experiment parts, and the order of insecticides upon molluscicidal effect was that of E.M., E.P.N., heptachlor and malathion. 2) $LD_{50}$ values are varied according to the exposure time in insecticide solution, and the longer the exposure time is, the lower the values of $LD_{50}$ is. 3) To take the exposure time in low concentration of insecticide solution for the long time would obtain the more molluscicidal effect. 4) The mortality rate increases in proportion as the concentration of insecticides increases.

• 한국환경과학회지
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• 제22권2호
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• pp.151-161
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• 2013

The assessment of personal exposure is a critical component in population-based epidemiologic studies of air pollution. This study was conducted to apply and compare the four exposure estimation methods of individual-level to air pollution concentration in a cohort including 2,283 subjects in Gwangyang, Korea. Individual-level exposure of air pollution were estimated using multiple approaches, including average across all monitors, nearest monitor, and spatial interpolation by inverse distance weighting and kriging. The mean concentrations of $PM_{10}$, $NO_2$, $SO_2$, CO, $O_3$ by four exposure estimation methods were slightly different but not significantly different from each other. Cross-validation showed that kriging was more accurate than other exposure estimation methods because kriging has probably predicted individual exposure levels equivalent to residential locations after estimating the parameters of a model according to the spatial surface of air pollution concentration. These data support that spatial interpolation methods may provide better estimates than selecting the value from the nearest monitor and averaging across values from all monitors by reflecting spatial attributes of air pollution on personal level.

• 한국환경보건학회지
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• 제48권3호
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• pp.151-158
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• 2022

Background: Chemical emissions in the environment have rapidly increased with the accelerated industrialization taking place in recent decades. Residents of industrial complexes are concerned about the health risks posed by chemical exposure. Objectives: This study was performed to suggest modeling methods that take into account multimedia and multi-pathways in human exposure and risk assessment. Methods: The concentration of benzene emitted at industrial complexes in Daesan, South Korea and the exposure of local residents was estimated using the Caltox model. The amount of human exposure based on inhalation rate was stochastically predicted for various activity stages such as resting, normal walking, and fast walking. Results: The coefficient of determination (R²) for the CalTOX model efficiency was 0.9676 and the root-mean-square error (RMSE) was 0.0035, indicating good agreement between predictions and measurements. However, the efficiency index (EI) appeared to be a negative value at -1094.4997. This can be explained as the atmospheric concentration being calculated only from the emissions from industrial facilities in the study area. In the human exposure assessment, the higher the inhalation rate percentile value, the higher the inhalation rate and lifetime average daily dose (LADD) at each activity step. Conclusions: Prediction using the Caltox model might be appropriate for comparing with actual measurements. The LADD of females was higher ratio with an increase in inhalation rate than those of males. This finding would imply that females may be more susceptible to benzene as their inhalation rate increases.

• 한국산업보건학회지
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• 제33권3호
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• pp.291-297
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• 2023

Objectives: An epidemiological investigation was requested for a worker who developed COPD and IPF after long-term molding and firing at a domestic tile manufacturing site. We would like to share the results of the exposure assessment and the estimation of past work. Methods: The content of crystalline silica in four raw materials was analyzed, and the respirable fraction of crystalline silica and dust generated in the air from molding and firing workers and other processes were measured. The measurement and analysis method referred to the NIOSH method. Results: The crystalline silica content of the raw material was 24~47%. The concentration of crystalline silica in the molding and firing process workers and the surrounding area was at the level of the exposure standards set by the Ministry of Employment and Labor and ACGIH, and the respirable and total dust exposure levels were generally low. The crystalline silica concentration of the area samples measured to estimate past work was about twice as high as the exposure standard of the Ministry of Employment and Labor (0.05 mg/m3), and the exposure levels of respirable dust were also quite high at 0.903 and 1.332 mg/m3. Conclusions: It was confirmed that tile molding and firing workers are currently exposed to a fairly high level of crystalline silica, and a high level is also confirmed in area samples to estimate past work. In the past, it is judged that the level of exposure would have been much higher due to differences in production volume, working method, presence/absence of local ventilation facilities, and process layout. When working in such a working environment for a long time, respiratory diseases such as lung cancer, COPD, and IPF can occur.

• 한국산업보건학회지
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• 제28권3호
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• pp.273-282
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• 2018

Objectives: Dustiness of nanomaterials is considered as exposure index of essential material. Research on dustiness of nanomaterial is needed to control exposure in workplaces. Method: Dustiness measurement using vortex shaker were installed in the laboratory. Nanomaterials, 1 g, was put in the glass test tube and shaked using vortex shaker. Aerosol dispersed was measured using scanning mobility particle sizer(SMPS) and optical particle counter(OPC). Mass concentration using PVC filter and cassette was measured and TEM grid sampling was conducted. Total particle concentration and size distribution were calculated. Image and chemical composition of particles in the air were observed using transmission electron microscopy and energy dispersive X-ray spectrometer. Eleven different test nanomaterials were used in the study. Results: Rank of mass concentration and particle number concentration were coincided in most cases. Rank of nanomateirals with low concentration were not coincided. Two types of fumed silica had the highest mass concentration and particle number concentration. Indium tin oxide, a mixture of indium oxide and tin oxide, had high mass concentration and particle number concentration. Indium oxide had very low mass concentration and particle number concentration. Agglomeration of nanoparticles in the air were observed in TEM analysis and size distribution. In this study, mass concentration and particle number concentration were coincided and two index can be used together. The range of dustiness in particle number concentration were too wide to measure in one method. Conclusion: Particle number concentration ranged from low concentration to high concentration depend on type of nanomaterial, and varied by preparation and amount of nanomaterial used. Further study is needed to measure dustiness of all nanomaterial as one reference method.

• 한국환경보건학회지
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• 제33권5호
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• pp.359-364
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• 2007

The aim of this study were to assess the personal exposure to volatile organic compounds (VOCs) and to estimate the personal exposure using time-weighted average model. Three target VOCs (benzene, toluene, xylene) were analyzed in personal exposure samples and residential indoor, residential outdoor and workplace indoor microenvironments samples in the iron mill 30 workers during working 5 days. Personal exposure to VOCs significantly correlated with workplace concentration p<0.05), suggesting workplace had strong source and major contribution to personal exposure. Personal exposure could be estimated with time activity pattern and time weighted average (TWA) model of residential indoor and workplace concentrations measured. Time weighted mean microenvironments concentrations were close approximately of personal exposure concentrations. Total exposure for participants can be estimated by TWA with microenvironments measurements and time activity pattern.

• 한국환경보건학회지
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• 제48권2호
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• pp.59-65
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• 2022

Background: Since people move through microenvironments rather than staying in one place, they may be exposed to both indoor and outdoor PM_2.5 concentrations. Objectives: The aim of this study was to assess the exposure level of each sub-population group and evaluate the contribution rate of the major microenvironments. Methods: Exposure scenarios for sub-population groups were constructed on the basis of a 2019 Time-Use survey and the previous literature. A total of five population groups were classified and researchers wearing MicroPEM simulated monitoring PM_2.5 exposure concentrations in real-time over three days. The exposure contribution for each microenvironment were evaluated by multiplying the inhalation rate and the PM_2.5 exposure concentration levels. Results: Mean PM_2.5 concentrations were 33.0 ㎍/m³ and 22.5 ㎍/m³ in Guro-gu and Wonju, respectively. When the exposure was calculated considering each inhalation rate and concentration, the home showed the highest exposure contribution rate for PM_2.5. As for preschool children, it was 90.8% in Guro-gu, 94.1% in Wonju. For students it was 65.3% and 67.3%. For housewives it was 98.2% and 95.8%, and 59.5% and 91.7% for office workers. Both regions had higher exposure to PM_2.5 among the elderly compared to other populations, and their PM_2.5 exposure contribution rates were 98.3% and 94.1% at home for Guro-gu and Wonju, respectively. Conclusions: The exposure contribution rate could be dependent on time spent in microenvironments. Notably, the contribution rate of exposure to PM_2.5 at home was the highest because most people spend the longest time at home. Therefore, microenvironments such as home with a higher contribution rate of exposure to PM_2.5 could be managed to upgrade public health.

• 한국식품조리과학회지
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• 제25권5호
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• pp.632-642
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• 2009

In this study the microbiological quality of vegetables was evaluated in relation to the sanitization methods used and vegetable types which consisted of raw food ingredients used in foodservice operations. We analyzed the microbial quantities on lettuce and spinach, which were used as leaf vegetables and cucumber and tomato, which were used as fruit vegetables according to various disinfection methods using different chlorine concentration(50 ppm, 100 ppm, 200 ppm) and exposure time(5 min, 10 min) over 5 days. When the effects of the disinfection methods on microbial qualities and sensory evaluation were analyzed, the following results were obtained. First, in the leaf vegetables, disinfection with a chlorine concentration of 200 ppm for a 5 minutes exposure time was needed to control microbial growth. Second, fruit vegetables sterilized with tap water had reduced microbial qualities after an extended amount of time relative to chlorine disinfection, that is, disinfection with a chlorine concentration of 50 ppm for 5 minutes exposure time was desirable.

• 한국방사선학회논문지
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• 제9권6호
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• pp.421-424
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• 2015

본 연구는 G광역시 N유치원을 대상으로 창문을 닫고 열은 상태에서 라돈 가스를 측정하였다. 측정 결과 라돈가스를 측정한 N유치원의 실내 평균 라돈농도는 창문을 닫았을 때 2.9pCi, 창문을 열었을 때 0.8pCi로 미국 일반인 공기 중 라돈가스 최대허용농도 기준치인 4pCi 이하의 값으로 나타났다. 이러한 결과는 N유치원에서 라돈 가스에 대한 피폭은 문제가 되지 않으나 라돈 가스가 폐에 축척이 되면 폐암과 같은 피해를 입을 수 있다. 따라서 방어적 측면에서 유치원 내의 창문을 자주 열어 환기를 하는 것이 매우 중요함을 알 수 있었다.