• Journal of the Society of Disaster Information
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• v.15 no.2
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• pp.239-248
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• 2019

Purpose: This study aims to enhance the resistance against sulfate attack compared to ordinary Portland cement (OPC) concrete by using liquid crystal display (LCD) as binder. Method: The fundamental properties including compressive strength and porosity of concrete replaced by LCD up to 15% at increments of 5% and in turn, the weight, volume, and strength loss of LCD-mixed concrete was analyzed. Results: For the concrete substituted by 5% of LCD, it showed the highest compressive strength at 28 days of curing, and particular at immersion of $Na_2SO_4$ solution, it was achieved the lowest loss of weight, volume and strength due to an decreased porosity at capillaries. In contrast, there is no distinct difference of the sulfate attack resistance between LCD-mixed concretes under exposure of $MgSO_4$ solution, excepted for OPC concrete. Conclusion: In this study, comparison of resistance to sulfate attack between LCD-mixed concretes, and it would be proposed the possibility of LCD usage as binder through long-term verification with extended replacement ratio and identification of changes of hydrates in the cement matrix.

• Toxicological Research
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• v.35 no.4
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• pp.361-369
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• 2019

1,2-Dichloropropane (1,2-DCP) has been used as an industrial solvent and a chemical intermediate, as well as in soil fumigants. Human exposure may occur during its production and industrial use. The target organs of 1,2-DCP are the eyes, respiratory system, liver, kidneys, central nervous system, and skin. Repeated or prolonged contact may cause skin sensitization. In this study, 1,2-DCP was dissolved in corn oil at 0, 2.73, 5.75, and 8.75 mL/kg. The skin of mice treated with 1,2-DCP was investigated using western blotting, hematoxylin and eosin staining, and immunohistochemistry. 1,2-DCP was applied to the dorsal skin and both ears of C57BL/6J mice. The thickness of ears and the epidermis increased significantly following treatment, and the appearance of blood vessels was observed in the dorsal skin. Additionally, the expression of vascular endothelial growth factor, which is tightly associated with neovascularization, increased significantly. The levels of protein kinase-B (PKB), phosphorylated PKB, mammalian target of rapamycin (mTOR), and phosphorylated mTOR, all of which are key components of the phosphoinositide 3-kinase/PKB/mTOR signaling pathway, were also enhanced. Taken together, 1,2-DCP induced angiogenesis in dermatitis through the PI3K/PKB/mTOR pathway in the skin.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.575-584
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• 2021

The critical low temperature and response of the behavioral tolerance of red sea bream Pagrus major fingerlings were determined using the continuous behavior monitoring system (CBMS). The behavior of the experimental organisms was observed by decreasing the water temperature by 2.0℃ and 4.0℃ every 12 hours and 24 hours in the range of 8.0-20.0℃. An unstable behavior pattern was observed in red seabream fingerlings exposed to water temperatures below 12.0℃, in which the swimming activity decreased and repeatedly stopped, regardless of the exposure time and water temperature fluctuation. The swimming ability of the organisms exposed to 8.0-10.0℃ decreased sharply, and the behavior of staying at the bottom of the test tank was observed. Only 50 % of the organisms survived due to the low-temperature stress, and all individuals died within six hours after the cold shock. In addition, the behavior index (BI) decreased rapidly, and the amplitude change of the coefficient of variation (CV) was found to have a greater variation than the other water temperatures (p<0.05). Low-temperature stress of red sea bream is promoted at 12.0℃, and it is interpreted as the tolerance limit, which can induce a sublethal response of the organisms exposed to cold shock of 8.0-10.0℃.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.23-32
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• 2020

This study investigated the thermal degradation and fading behavior of PTT dyed with vat dye and its dyeing ability. The PTT sample was dyed with vat dye using an acid treatment and pad-steam method to improve the dyeing performance. This method made dye particle nanosize and allowed it to penetrate the polymer material easily. The sample dyed using the pad-steam method showed level dyeing and enhanced dyeing affinity, compared to the batch-dyeing method. The degradation behavior of PTT dyed with vat dye after each heat and UV treatment was examined with the change in tensile strength or K/S value on the sample. The tensile strength and K/S values of the sample dyed with vat dye after the heat and UV treatment decreased with increasing temperature and exposure time. Although they showed high degradation under severe conditions, its rate constant was improved compared to the samples dyed with disperse dye. Consequently, acid treatment and the pad-steam method resulted in the introduction of vat dye on PTT. In addition, the PTT dyed with vat dye showed enhanced thermal and UV resistance because of their high molecular weight and chemical structure for stable adsorption behavior.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.2
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• pp.230-246
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• 2023

Objectives: The climate crisis has arrived and heat-related illnesses are increasing. It is necessary to discover new high-heat risk industries and understand the environment . It is also necessary to prioritize risks of industries that have not been included in the management target to date. The study was intended to monitor and evaluate the thermal risk of high-priority workplaces. Methods: A prioritization method was developed based on five factors: occurrence of and death due to heat-related illnesses, work environment monitoring, indoor work rate, small heat source, and limited heat dissipation. it, was applied to industrial accidents caused by heat-related illnesses. Wet bulb temperature index and apparent temperature were measured in July and August at 24 workplaces in seven industries and assessed for thermal risk. Results: The wet bulb temperature index was in the range of 23.8~31.9℃, and exposure limits were exceeded in the growing of crops, food services activities and accommodation, and building construction. The apparent temperature was in the range of 26.8~36.7℃, and exceeded the temperature standard for issuing heatwave warnings in growing of crops, food services activities and accommodation, warehousing, welding, and building construction. Both temperature index in growing of crops and building construction were higher than the outside air temperature. Conclusions: In the workplace, risks in industries that have not be controlled and recognized through existing systems was identified. it is necessary to provide break times according to the work-rest time ratio required during dangerous time period.

• Journal of Environmental Health Sciences
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• v.49 no.6
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• pp.334-343
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• 2023

Background: South Korea's Act on Registration and Evaluation, etc. of Chemicals (known as K-REACH) was established to protect public health and the environment from hazardous chemicals. 4,4'-Methylenedianiline (MDA), which is used as a major intermediate in industrial polymer production and as a vulcanizing agent in South Korea, is classified as a toxic substance under the K-REACH act. Although MDA poses potential ecological risks due to industrial emissions and hazards to aquatic ecosystems, no ecological risk assessment has been conducted. Objectives: The aim of this study is to assess the ecological risk of MDA by identifying the actual exposure status based on the K-REACH act. Methods: Various toxicity data were collected to establish predicted no effect concentrations (PNECs) for water, sediment, and soil. Using the SimpleBox Korea v2.0 model with domestic release statistical data and EU emission factors, predicted environmental concentrations (PECs) were derived for ten sites, each referring to an MDA-using company. Hazard quotient (HQ) was calculated by ratio of the PECs and PNECs to characterize the ecological risk posed by MDA. To validate the results of modeling-based assessment, concentration of MDA was measured using in-site freshwater samples (two to three samples per site). Results: PNECs for water, sediment, and soil were 0.000525 mg/L, 4.36 mg/kg dw, and 0.1 mg/kg dw, respectively. HQ for surface water and sediment at several company sites exceeded 1 due to modeling data showing markedly high PEC in each environmental compartment. However, in the results of validation using in-site surface water samples, MDA was not detected. Conclusions: Through an ecological risk assessment conducted in accordance with the K-REACH act, the risk level of MDA emitted into the environmental compartments in South Korea was found to be low.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.12-18
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• 2023

The effective evacuation strategy according to the accident scenario is crucial to minimize human casualties in the event of toxic gas leak accidents. In this study, the effect of the direction of a building and the location of an industrial complex on the increase in indoor concentration and outdoor diffusion was examined under the same leakage conditions, and effective evacuation criteria were established. In addition, the guidelines for building directions were suggested when constructing buildings that would mitigate human damage caused by chemical accidents. Three scenarios where buildings faced the front, side, and rear of the leakage direction were investigated through CFD simulations. The results revealed that when the building faced the industrial complex, both indoor and outdoor average gas concentrations increased significantly, reaching up to 120 times higher than the other two orientations. Moreover, the indoor space was filled with toxic gas substances more than twice in the same time due to the rapid increase of indoor concentration rate. In cases where the building's windows were positioned at the front, toxic gas stagnation occurred around the building due to pressure differences and reduced flow velocities. Based on our findings, the implementation of these guidelines will contribute to safeguarding residents by minimizing exposure to toxic gas during chemical accidents.

• Industry Promotion Research
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• v.9 no.1
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• pp.39-45
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• 2024

Dangerous tasks that occur every day at industrial site manufacturing plants, which have recently been making rapid changes, were classified by type, and the effect of mobile circuit television (CCTV) on safety accidents among daily safety management methods was analyzed. The subject of the study is about 3,000 workers who manage the infrastructure facility sector to supply utilities such as gas, water, and electricity to the display manufacturing process located in Asan City, and the study was conducted based on the daily dangerous work from 2019 to 2022, and during this study period, many construction works such as new investment and expansion of construction and manufacturing processes were occurring at the site. As a result, the rate of safety accidents and exposure to risks are expanding, and most of the safety accidents occurred because the sectors that did not follow the basics and the safety measures on the site were not implemented. In this paper, it was confirmed that there is an accident reduction effect according to the relationship between the dangerous work classified according to the work importance and the mobile CCTV shooting rate. Considering the characteristics of the manufacturing plant site, it can be used to play the role of basic data for preventing safety accidents based on the expansion of the introduction of a new safety management culture in the future.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.3
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• pp.380-391
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• 2015

Objectives: The objective of this study is to assess airborne particulate matter pollution and its effect on health of residents living near Ansim Briquette Fuel Complex and its vicinities. Also, this study measured and analyzed the concentration of TSP, $PM_{10}$, $PM_{2.5}$, and heavy metals which influences on the environmental and respiratory disease in Ansim Briquette Fuel Complex, Daegu, Korea. Methods: In this study, we analyzed various environmental pollutants such as particulate matter and heavy metals from Ansim Briquette Fuel Complex that adversely affected local residents's health. In particular, we verified the concentration distribution and characteristics of exposure for TSP, $PM_{10}$, and $PM_{2.5}$ among particulate matters, and heavy metals(Cd, Cr, Cu, Mn, Ni, Pb, Fe, Zn, and Mg). In that regard, the official test method on air pollution in Korea for analysis of particulate matter and heavy metal in atmosphere were conducted. The large capacity air sampling method by the official test method on air pollution in Korea were applied for sampling of heavy metals in atmosphere. In addition, we evaluated the concentration of seasonal environmental pollutants for each point of residence in Ansim Briquette Fuel Complex and surrounding area. The sampling measured periods for air pollutants were from August 11, 2013 to February 21, 2014. Furthermore, we measured and analyzed the seasonal concentrations(summer, autumn and winter). Results: The average concentration for TSP, $PM_{10}$, and $PM_{2.5}$ by direct influence area at Ansim Briquette Fuel Complex were 1.7, 1.4 and 1.9 times higher than reference region. In analysis results of seasonal concentrations for particulate matter in four direct influence and reference area, concentration levels for winter were generally somewhat higher than concentrations for summer and autumn. The average concentrations for Cd, Cr, Mn, Ni, Pb, Fe, and Zn in direct influence area at Ansim Briquette Fuel Complex were $0.0008{\pm}0.0004{\mu}g/Sm^3$, $0.0141{\pm}0.0163{\mu}g/Sm^3$, $0.0248{\pm}0.0059{\mu}g/Sm^3$, $0.0026{\pm}0.0011{\mu}g/Sm^3$, $0.0272{\pm}0.0084{\mu}g/Sm^3$, $0.4855{\pm}0.1862{\mu}g/Sm^3$, and $0.3068{\pm}0.0631{\mu}g/Sm^3$, respectively. In particularly, the average concentrations for Cd, Cr, Mn, Ni, Pb, Fe, and Zn in direct influence area at Ansim Briquette Fuel Complex were 1.9, 3.6, 2.1, 1.9, 1.4, 2.6, and 1.2 times higher than reference area, respectively. The continuous monitoring and management were required for some heavy metals such as Cr and Ni. Moreover, the average concentration in winter for particulate matter in direct influence area at Ansim Briquette Fuel Complex were generally higher than concentrations in summer and autumn. Also, average concentrations for TSP, $PM_{10}$, and $PM_{2.5}$ were from 1.5 to 2.0 times, 1.2 to 1.8 times, and 1.1 to 2.3 times higher than reference area, respectively. In results for seasonal atmospheric environment, TSP, $PM_{10}$, $PM_{2.5}$, and heavy metal concentrations in direct influence area were higher than reference area. Especially, the concentrations in C station were a high level in comparison with other area. Conclusions: In the results, some particulate matters and heavy metals were relatively high concentration, in order to understand the environmental pollution level and health effect in surrounding area at Ansim Briquette Fuel Complex. The concentration of some heavy metals emitted from direct influence area at Ansim Briquette Fuel Complex were relatively higher than reference area. In particular, average concentration for heavy metals in this study were higher than average concentrations in air quality monitoring station for heavy metal for 7 years in Deagu metropolitan region. Especially, the residents near Ansim Briquette Fuel Complex may be exposed to the pollutants(TSP, $PM_{10}$, $PM_{2.5}$, and heavy metals, etc) emitted from the factories in Ansim Briquette Fuel Complex.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.1
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• pp.8-15
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• 1995

The reliable measurement of metal in biological media in human body is one of critical indicators for the proper evaluation of its toxic effect on human health. Recently in Korea the necessity of quality assurance of measurement in occupational health and occupational hygiene fields brought out regulatory quality control program. Lead is often used as a standard metal for the program in both fields of occupational health and hygiene. During last 20 years lead poisoning was prevalent in Korea and still is one of main heavy metal poisoning and the capability of the measurement of blood lead is one of prerequisites for institute of specialized occupational health in Korea. Furthermore blood lead is most important indicator to evaluate lead burden of human exposure to lead and the reliable and accurate analysis is most needed whenever possible. To evaluate the extent of the interlaboratory differences of blood lead measurement in several well-known institute specialized in occupational health in Korea, authors prepared 68 blood samples from two storage battery industries and all samples were divided into samples with 2 ml. One set of 68 samples were analyzed by authors's laboratory(Soonchunhyang University Institute of Industrial Medicine: SIIM) and 40 samples of other set were analyzed by C University Institute of Industrial Medicine(CIIM) and the rest 28 samples of other set were analyzed by Japanese institute(K Occupational Health Center:KOHC). Authors also prepared test bovine samples which were obtained from Japanese Federation of Occupational Health Organization (JFOHO) for quality control. Authors selected 2 other well-known occupational health laboratories and one laboratory specialized for instrumental analysis. A total of 6 laboratories joined the interlaboratory comparison of blood lead measurement and the results obtained were as follows: 1. There was no significant difference in average blood lead between SIIM and CIIM in different group of blood lead concentration, and the relative standard deviation of two laboratories was less than 3.0%. On the other hand, there was also no significant difference of average blood lead between SIIM and KOHC with relative standard deviation of 6.84% as maximum. 2. Taking less than 15% difference of mean or less than 6 ug/dl difference in below 40 ug/dl in whole blood as a criteria of agreement of measurement between two laboratories, agreement rates were 87.5%(35/40) and 78.6%(22/28) between SIIM and CIIM, SIIM and KOHC respectively. 3. The correlation of blood lead between SIIM and CIIM was 0.975 (p=0.0001) and the regression equation was SIIM = 2.19 + 0.9243 ClIM, whereas the correlation between SUM and KOHC was O.965(p=0.0001) with the equation of SIIM = 1.91 + 0.9794 KOHC. 4. Taking the reference value as a dependent variable and each of 6 laboratories's measurement value as a independent variable, the determination coefficient($R^2$) of simple regression equations of blood lead measurement for bovine test samples were very high($R^2>0.99$), and the regression coefficient(${\beta}$) was between 0.972 and 1.15 which indicated fairly good agreement of measurement results.