• Journal of Environmental Impact Assessment
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• v.25 no.6
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• pp.414-431
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• 2016

There are numerous closed and abandoned mines in Korea, from which diverse heavy metals (e.g., As, Cd, Cu, Pb, Zn) are released into the surrounding soil, groundwater, surface water, and crops, potentially resulting in detrimental effects on the health of nearby residents. Therefore, we performed human risk assessments of two abandoned metal mines, Yanggok (YG) and Samsanjeil (SJ). The exposure parameters used in this assessment were specific to residents near mines and the included exposure pathways were relevant to areas around metal mines. The computed total excess carcinogenic risks for both areas exceeded the acceptable carcinogenic risk ($1{\times}10^{-6}$), indicating that these areas are likely unsafe due to a carcinogenic hazard. In contrast, the non-carcinogenic risks of the two areas differed among the studied receptors. The hazard indices were higher than the unit risk (=1.0) for male and female adults in YG and male adults in SJ, suggesting that there are non-carcinogenic risks for these groups in the study areas. However, the hazard indices for children in YG and female adults and children in SJ were lower than the unit risk. Consumption of groundwater and crops grown in the area were identified as major exposure pathways for carcinogenic and non-carcinogenic hazards in both areas. Finally, the dominant metals contributing to carcinogenic and non-carcinogenic risks were As and As, Cu, and Pb, respectively. In addition, the carcinogenic and non-carcinogenic risks of YG were evaluated to be 10 and 4 times higher than those of SJ, respectively, resulted from the relatively higher exposure concentration of As in groundwater within SJ area. Because of lacking of several exposure parameters, some of average daily dose (ADD) could not be computed in this study. Furthermore, it is likely that the ADDs of crop-intake pathway included some errors because they were calculated using soil exposure concentrations and bioconcentration factor (BCF) rather than using crop exposure concentrations.

• Journal of Radiation Industry
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• v.17 no.4
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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.

• Fisheries and Aquatic Sciences
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• v.5 no.4
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• pp.295-301
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• 2002

Experiments were carried out to investigate the effects of metal interaction on the accumulation and elimination of Cd and Cu in the liver of flounder, Paralichthys olivaceus, exposed to sub-chronic Cd (0, 5, 10, 50, 100 ${\mu}g/L$)/Cu $(10 {\mu}g/L)$ mixture. Cd exposure resulted in an increased Cd accumulation in the liver of flounder for exposure periods and concentration, and Cd accumulation increased linearly with exposure time. Cu accumulation profiles were similar to those of Cd. Cd concentration in the liver significantly decreased at the 10th depuration period and elimination rate was $66.20\%,\;86.22\%$ in 50 and $100 {\mu}g/L$at the end of depuration periods, respectively. Although, Cu elimination was similar to Cd elimination phase, Cd elimination rate was higher than that of Cu. Co-relationship of Cd and Cu have a positive correlation coefficient r=0.8620 (P<0.001) and support the strong relationship between Cd and Cu accumulation. As increase with the Cd exposure concentration, there were significant (P<0.001) differences between Cd and Cu accumulation.

• Advances in environmental research
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• v.5 no.2
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• pp.79-94
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• 2016

In order to evaluate the contamination and health risk, levels of six hazardous elements i.e., Cr, Ni, Cu, As, Cd and Pb in soils of 12 different land-uses were measured. The average concentration of Cu, Cr, Ni, Pb, As and Cd in soils were 267, 239, 206, 195, 58 and 16 mg/kg, respectively. Levels of each metal exceeded the environmental action level for soils, which could pose significant risk to human. The metal concentrations were subsequently used to establish hazard indices (for adults and children) where the 5th and 95th percentile values were used to derive the hazard index through different exposure pathways (ingestion, dermal contact and inhalation). Considering the total exposure through each of the three pathways, the hazard index elucidates that there was a potency of non-cancer risk at most of the sites for both the adults and children. The findings of this study suggested that different land-use soils were severely contaminated with hazardous elements and attention is needed on the potential health risks to the exposed inhabitants.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.3
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• pp.249-255
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• 2020

Objective: The purpose of this study was to provide technical information about the management of occupational exposure limits(OELs) for substances with completely revised ACGIH TLVs. Methods: The history of ACGIH TLVs for aluminum compounds, the reason for the complete revision of the related ACGIH TLV in 2008, and OELs for them in respective countries were reviewed. In addition, the results of a 2019 work environment assessment for aluminum compounds in Korea were reviewed. Results: In 1979, the ACGIH set up the TLVs for aluminum compounds considering types of compounds such as metal dust, pyro powders, welding fumes, soluble salts, alkyls, and aluminum oxide. However, in 2008 the ACGIH withdrew the TLVs for all types of aluminum and its compounds and adopted new TLVs for aluminum metal and insoluble compounds. This can cause confusion in many countries in the management of exposure to aluminum compounds because they adopt or refer to the ACGIH TLVs. Conclusion: Although Korea is setting occupational exposure limits by referring to the ACGIH's TLVs, it is necessary to sufficiently review whether it is necessary to accept the TLVs as they are if a TLV is completely changed, like took place with the revision of aluminum compounds in 2008.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.4
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• pp.413-421
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• 2014

Since the structural temperature of a flight vehicle flying at high speed rises rapidly due to aerodynamic heating, it is necessary for optimum structural design to obtain proper material properties at high temperature by taking into account of its operational environment. For a special alloy, analysis data on strength change due to exposure time to high temperature are very limited, and most of them are for an exposure time longer than 30 minutes for long term operations. In this study, base and weld metal samples of Ti-6Al-4V alloy had been prepared and high temperature tensile tests with induction heating were performed, and then high temperature strength characteristics and strength recovery characteristics through cooling have been analyzed. Pre-tests to determine maximum heating rate were performed, and response characteristics for temperature control were confirmed. As a result, high temperature tensile strength appeared to be lower than that of room temperature, but it was higher than that of high temperature of 30 minite exposure listed in MMPDS. In strength recovery through cooling Ti-6Al-4V alloy has shown higher recovery rate compared with other alloys.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.4
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• pp.517-527
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• 2023

Objectives: We examine cases of chemical poisoning that occurred in the cleaning of metal parts and the regulations on halogenated solvents in other countries and propose regulations necessary to prevent chemical poisoning from halogenated solvents. Methods: We collected cases of chemical poisoning through the website of the Korea Occupational Safety and Health Agency. A review of the literature was conducted focusing on regulations related to halogenated solvents in the United States and the European Union, particularly for cleaning metal parts. Among the Material Safety Data Sheets submitted to the government, MSDS containing eleven substances were extracted to confirm the composition and product use. We investigated cleaning methods for metal parts used in South Korea. For the hazard classification, the European Chemicals Agency or Japan's NITE's website was used. Results: In the case of poisoning, the cleaning methods involving trichloromethane were dipping and dry, which was not found in the literature. It was confirmed that many halogenated solvents and dimethyl carbonate were used for metal cleaning in South Korea. In vapor degreasing using TCE in the USA, even if the facility is strictly managed, such as by installing cooling coils in open cleaning facilities, the risk of exposure to TCE is considered to be not only carcinogenic but also a concern for acute and chronic effects. In comparison, exposure through Korean work methods such as dipping and drying operations is inevitably much higher. Conclusions: The transition to water-based cleaning with low-hazard chemicals should be a priority in the cleaning process. In the case of metal parts that require precise cleaning, if the use of a halogenated solvent is inevitable, a closed degreasing facility should be used to minimize exposure. The current regulations in the Occupational Safety and Health Act, the Chemical Substances Control Act, and the Air Environment Conservation Act do not require cleaning facilities to minimize emissions. To protect the health of workers using halogenated solvents to clean metal parts, regulations that require a fundamental reduction in exposure will be necessary.

• Journal of Environmental Health Sciences
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• v.36 no.1
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• pp.14-19
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• 2010

Based on a nationwide survey of the consumption of oriental medicine by the Korean population, we estimated the potential risk from the inadvertent ingestion of heavy metals such as Pb, Hg, As, and Cd as a result such consumption. Compared to the provisional daily intake limit, heavy metal intake through oriental medicine resulted in hazard quotients of less than one. The upper $90^{th}$ percentile exposure estimates for each metal also showed insignificant risk. In relation to inorganic forms that are known carcinogens the excess cancer risk was less than $1{\times}10^7$. Based on the results of this study exposure to Pb, Hg, As, or Cd through oriental medicine intake appeared to be negligible and would not cause a significant impact on health.

• Journal of fish pathology
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• v.24 no.3
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• pp.269-278
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• 2011

Gene expression of two glyceraldehyde-3-phosphate dehydrogenase (GAPDH) paralogs was examined during Edwardsiella tarda challenge and heavy metal exposures in mud loach (Misgurnus mizolepis; Cypriniformes) kidney and spleen. Transcription of the two mud loach GAPDH paralogs (mlGAPDH-1 and mlGAPDH-2) was significantly modulated by these stimulatory challenges in an isoform-dependent manner. Based on the real-time RT-PCR analysis, the mlGAPDH-2 transcripts were more preferentially induced by E. tarda challenge, whereas the mlGAPDH-1 transcripts were proven to show more inducibility in response to heavy metal exposure using Cd, Cu, Mn and Zn at $5{\mu}M$. Their isoform-specific response patterns were closely in accordance with the TF binding profiles in promoter and intron-1 of the two mlGAPDH isoforms, in which the mlGAPDH-2 has more binding sites for immune-related transcription factors than mlGAPDH-1 while the mlGAPDH-1 possesses exclusively metal responsive elements in its intron. Collectively, the mlGAPDHs are potentially involved in cellular pathways independent of glycolysis and the two GAPDH paralogs might undergo functional diversification or subfunctionalization at least at the transcription level.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.1
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• pp.85-97
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• 2024

Objectives: This study was intended to investigate the revision status of the occupational exposure standards for aluminum at home and abroad; to investigate worker exposure at domestic aluminum manufacturing and handling workplaces; to conduct social and economic evaluation for the revision of domestic aluminum exposure limits. Methods: We investigated the current status of occupational exposure limits for aluminum at home and abroad, and analyzed supporting data. An exposure survey was conducted targeting domestic aluminum manufacturing and handling workplaces. Based on these, revised aluminum occupational exposure limits were proposed. Results: The major aluminum exposure limits at home and abroad show a notable difference. The toxicity of aluminum, which was revealed through animal experiments and epidemiological investigations. The average concentration of aluminum in the air at 12 workplaces was 0.016 mg/m³, and the maximum was 0.0776 mg/m³. When total dust and respiratory dust were measured side by side and simultaneously for the same process, 12.1% of the total mass concentration of aluminum dust was respiratory dust. As a result of measuring and comparing the size distribution of dust with an optical particle counter in real time, 48.1% of the total dust in the form of welding fume and pyro-powder was respiratory dust. Based on the literature review and workplace survey, three proposals for changing the aluminum exposure limit were proposed. Proposal (1): For all types, 10 mg/m³ is unified as the exposure limit except for soluble salts and alkyls. Proposal (2): 1(R) mg/m³ as the exposure limit for all forms except soluble salts and alkyl. Proposal (3): 1(R) mg/m³ for pyro-powder and welding fume, and 10 mg/m³ for metal dust, aluminum oxide, and insoluble compounds as exposure standards. A pyro-powder was defined as dry aluminum powder of 200 mesh size (74 ㎛) or smaller (larger size classified as metal dust). Reason for setting: In the workplace survey, the ratio of respiratory dust to total dust was analyzed to be about 1:10, so it was judged that the domestic standard and the ACGIH standard were compatible. Conclusions: In all scenarios according to the revision of the exposure standard, the B/C ratio was greater than 1 or only benefits existed, so it was evaluated as sufficiently reasonable as a result of the socio-economic evaluation.