• 방사선산업학회지
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• 제17권4호
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• pp.509-518
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• 2023

The Kori Unit 1 nuclear power plant, which is planned to be dismantled after permanent shutdown, is expected to generate a large amount of various types of radioactive waste during the dismantling process. For the disposal of Very-low-level waste, which is expected to account for the largest amount of generation, the Korea Radioactive waste Agency (KORAD) is in the process of detailed design to build a 3-phase landfill disposal facility in Gyeongju. In addition, a large container is being developed to efficiently dispose of metal and concrete waste, which are mainly generated as Very low-level waste of decommissioning. In this study, based on the design characteristics of the 3-phase landfill disposal facility and the large container under development, radiation exposure dose evaluation was performed considering the normal and accident scenarios of radiation workers during operation. The direct exposure dose evaluation of workers during normal operation was performed using the MCNP computer program, and the internal and external exposure dose evaluation due to damage to the decommissioning waste package during a drop accident was performed based on the evaluation method of ICRP. For the assumed scenario, the exposure dose of worker was calculated to determine whether the exposure dose standards in the domestic nuclear safety act were satisfied. As a result of the evaluation, it was confirmed that the result was quite low, and the result that satisfied the standard limit was confirmed, and the radiational disposal suitability for the 3-phase landfill disposal facility of the large container for dismantled radioactive waste, which is currently under development, was confirmed.

• 한국산업보건학회지
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• 제28권1호
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• pp.100-107
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• 2018

Objectives: This study examines exposure to hazardous substances in the working environment caused by exposure to toxic substances produced in the aluminum die casting process in the automobile manufacturing industry. Materials and Methods: The exposure concentration levels, detection rates and time-trend of 15 hazardous factors in the aluminum die casting process over 10 years(from 2006 to 2016) were used as a database. Results: The study found that hazardous factors in the aluminum die casting process were mostly metals. The rate for detected samples was 70.6%(405 samples), and that for not detected samples was 29.4%. The noise for an eight-hour work shift showed a 49.7% exceedance rate for TLV-TWA. Average noise exposure was 89.0 dB. The maximum exposure level was 105.1 dB. Conclusion: The high numbers of no-detection rates for hazardous substance exposure shows that there is no need to do a work environment measurement. Therefore, alternatives are necessary for improving the efficiency and reliability of the work environment measurement. Moreover, to prevent noise damage, reducing noise sources from automation, shielding, or sound absorbents are necessary.

• 한국환경보건학회지
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• 제49권4호
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• pp.210-217
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• 2023

Background: N-nitrosamines are carcinogenic substances often found in rubber products. They are produced when certain additives of rubber products react with nitrite in saliva or air. Exposure assessment for the proper management and communication of N-nitrosamines in rubber balloons should be carried out. Objectives: This study was conducted to determine the concentrations of N-nitrosamines in rubber balloons in the South Korean market and assess exposure among Korean children. Methods: Forty eight rubber balloon products in the domestic market were purchased and a total of 68 balloons were analyzed for N-nitrosamines and N-nitrosatable substances. Chemical analysis was conducted by HPLC-MS/MS according to the method EN 71-12. For exposure assessment, an exposure algorithm and coefficients were obtained from previous studies. Results: Among the 68 rubber balloons, N-nitrosamines were detected in 18 (26.5%) with an average level of 60.77 ㎍/kg. N-Nitrosatable substances were detected in 44 products (64.7%) with an average level of 1353.33 ㎍/kg. As a result of the exposure evaluation, the exposure dose differed according to how exposure coefficients were applied. The median exposure (50th percentile) was higher in the age group of 6~12 years, and high exposure (95th percentile) was higher in the age group of 13~18. Conclusions: We evaluated the N-nitrosamines contained in rubber balloons purchased in the domestic market and assessed oral exposure among South Korean children. For integrated risk management of N-nitrosamines, further studies and discussion regarding exposure and risk assessment are required.

• 아동학회지
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• 제26권4호
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• pp.101-112
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• 2005

Subjects were 279 parents of 4- and 5-year-old day care children. Statistical techniques were factor analysis, t-test, ANOVA, Pearson's correlation, and multiple regression. Major findings were that parents with higher levels of education and income showed a higher level of attitudes and coping behavior toward preschoolers' exposure to secondhand smoke. Parents who were smokers had a higher level than non-smokers of knowledge and coping with preschoolers' secondhand smoke. Parents with higher levels of knowledge and more negative attitudes about secondhand smoke were more active in dealing with secondhand smoke. Parents' knowledge and attitudes were significant predictors of their coping behavior with preschoolers' secondhand smoke. Parents' knowledge was more predictive of parents' coping behavior than their attitudes.

• Safety and Health at Work
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• 제7권3호
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• pp.251-255
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• 2016

Background: Building demolition can lead to emission of dust into the environment. Exposure to silica dust may be considered as an important hazard in these sites. The objectives of this research were to determine the amount of workers' exposure to crystalline silica dust and assess the relative risk of silicosis and the excess lifetime risk of mortality from lung cancer in demolition workers. Methods: Four sites in the Tehran megacity region were selected. Silica dust was collected using the National Institute for Occupational Safety and Health method 7601 and determined spectrophotometrically. The Mannetje et al and Rice et al models were chosen to examine the rate of silicosis-related mortality and the excess lifetime risk of mortality from lung cancer, respectively. Results: The amount of demolition workers' exposure was in the range of $0.085-0.185mg/m^3$. The range of relative risk of silicosis related mortality was increased from 1 in the workers with the lowest exposure level to 22.64/1,000 in the employees with high exposure level. The range of the excess lifetime risk of mortality from lung cancer was in the range of 32-60/1,000 exposed workers. Conclusion: Geometric and arithmetic mean of exposure was higher than threshold limit value for silica dust in all demolition sites. The risk of silicosis mortality for many demolition workers was higher than 1/1,000 (unacceptable level of risk). Estimating the lifetime lung cancer mortality showed a higher risk of mortality from lung cancer in building demolition workers.

• 한국대기환경학회지
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• 제16권6호
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• pp.625-631
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• 2000

Practical devices for measuring personal exposure to nitrogen dioxide(NO$_2$) have been made for epidemiological studies of the health effects of air pollution Standard methods for NO$_2$ measurement such as the chemiluminescent method and Saltzman method are not suitable for personal exposure because they are heavy, large and complicated to operate. In this study, a passive monitor was tested for the measurements of indoor and outdoor NO$_2$ level. Through a comparative analysis of data sets obtained by on-site chemiluminescence system, we assessed the accuracy and precision of NO$_2$ passive monitors. We also examined the possibility of passive monitor in the study of indoor, outdoor and personal NO$_2$ exposure. The accuracy and precision of NO$_2$ passive monitor were analyzed assuming measurements of on-site chemiluminescence system is reference value and using duplicated measure- ments, respectively. From these analysis the NO$_2$ passive monitor was useful for measuring indoor, outdoor and personal exposure. And NO$_2$ level from on-site chemiluminescence systems could not properly represent the personal NO$_2$ exposure as well as indoor and outdoor level of ones house. Personal exposures were correlated more strongly with indoor NO$_2$ concentrations than with outdoor NO$_2$ concentrations. Since activity pattern of each person is different, it was considered that personal daily behavior and life-style might prevent the air pollutant exposure.

• 대한방사선기술학회지:방사선기술과학
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• 제44권6호
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• pp.599-605
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• 2021

The International Electrotechnical Commission (IEC) 62494-1 has defined the exposure index (EI) that have a proportional relationship with the dose incident on the image receptor, and target exposure index (EI_T), deviation index (DI). In this study, an appropriate EI_T for skull radiography was established through the diagnostic reference level (DRL) and changes in DI were confirmed. Entrance surface dose (ESD) and EI were obtained using the computed radiography system displayed the EI as per IEC on console and skull phantom by experiment based on the national average exposure conditions announced in 2012 and 2019. And appropriate EI_T was established by applying the DRL in 2012 and 2019. As a results, the EI_T is changed according to the change in the DRL, and the exposure condition that becomes the ideal DI according to the change in the EI_T also has a difference of about 1.41 times. DRL is recommended to optimize the patient dose, however it is difficult to measure in real time at medical institutions whereas EI and DI are displayed on the console at the same time as exposure. When the EI_T is set based on the DRL and the DI is closed to an ideal value, it is useful as a patient dose management tool. Therefore, when the EI_T is periodically managed along with the revision of the DRLs, the patient dose can be optimized through the EI, EI_T and DI.

• Environmental Analysis Health and Toxicology
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• 제30권
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• pp.4.1-4.11
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• 2015

Objectives: This survey was designed to conduct the first nationwide dietary exposure assessment on hazardous substances including the intakes of functional food and herbal medicine. In this paper, we introduced the survey design and the results of the dietary exposure status and internal exposure levels of lead (Pb), cadmium (Cd), and mercury (Hg). Methods: We selected 4867 subjects of all ages throughout Korea. We conducted a food survey, dietary survey, biomonitoring, and health survey. Results: Pb and Cd were the highest (median value) in the seaweed ($94.2{\mu}g/kg$ for Pb; $594{\mu}g/kg$ for Cd), and Hg was the highest in the fish ($46.4{\mu}g/kg$). The dietary exposure level (median value) of Pb was $0.14{\mu}g/kg$ body weight (bw)/d, $0.18{\mu}g/kg$ bw/d for Cd, and $0.07{\mu}g/kg$ bw/d for Hg. Those with a blood Pb level of less than $5.00{\mu}g/dL$ (US Centers for Disease Control and Prevention, reference value for those 1 to 5 years of age) were 99.0% of all the subjects. Those with a blood Cd level with less than $0.30{\mu}g/L$ (German Federal Environmental Agency, reference value for non-smoking children) were 24.5%. For those with a blood Hg level with less than $5.00{\mu}g/L$ (human biomonitoring I, references value for children and adults, German Federal Environmental Agency) was 81.0 % of all the subjects. Conclusions: The main dietary exposure of heavy metals occurs through food consumed in a large quantity and high frequency. The blood Hg level and dietary exposure level of Hg were both higher than those in the European Union.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.185-186
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• 2007

• 환경위생공학
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• 제16권1호
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• pp.1-8
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• 2001

Since most people spend over 80% of their time indoor, indoor air quality tends to be the dominant contributor to personal exposure. In this study, indoor and outdoor $NO_2$concentrations were measured and compared with simultaneously personal exposures of 27 house-wives and female workers of kindergarten. Time activity pattern and house characteristics were used to determine the effects of these factors on personal exposure. Since house-wives student spent most their times in indoor with mean of 89.8%, their $NO_2$ exposure was associated with indoor $NO_2$ level(r= 0.92) rather than outdoor $NO_2$ level(r= 0.87). female workers were also associated with indoor $NO_2$ level(r= 0.70) though sample number were small. Using time-weighted average model, $NO_2$ exposures of house-wives were estimated by $NO_2$ measurements in indoor home and outdoor home levels. Estimated $NO_2$ personal exposures were significantly correlated with measured $NO_2$ personal exposures (r= 0.90). These results might mean that air pollutants exposure of old and feeble persons, and infants could be estimated by measuring concentrations of indoor home.