• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.3
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• pp.156-161
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• 2011

Objectives: Tetrahydrofuran (THF) is a colorless, water-miscible organic liquid with low viscosity at standard temperature and pressure. THF has been used as a solvent and a precursor for various syntheses of polymers. However, THF is known to irritate to the eyes, skin and mucus membranes. Overexposure by inhalation, ingestion or skin contact may produce nausea, dizziness, headaches, respiratory irritation and possible skin burns. The purpose of this study is to evaluate of the worker exposure and characteristics of workers in the workplaces that use or manufacture THF. Methods: Sixteen factories in Korea, which manufacture or use THF, were selected for this study and a total of 130 air samples including 104 time-weighted average (TWA) samples and 26 short-term exposure limit (STEL) samples, were collected. Air samples were collected with charcoal tube (100mg/50mg) and analyzed by gas chromatograph/flame ionization detector(GC/FID). Results: The TWA concentration of THF was 16.05ppm (GM) at PS script printing, 2.32ppm (GM) at PVC stabilizer, 1.03ppm (GM) at Lithium triethylborohydride, 0.63ppm (GM) at Polytetramethylene ether glycol(PTMEG), 0.42ppm (GM) at Manufacturing THF, 0.13ppm (GM) at Glue and 0.12ppm (GM) at synthetic rubber/resins. Two out of sampes for PS script printing exceeded 50ppm as 8-hour exposure limit of MOEL. The short term exposure to THF was 54.77ppm (GM) at PS script printing, 17.10ppm (GM) at PTMEG, 13.76ppm (GM) at Manufacturing THF, 2.86ppm (GM) at Lithium triethylborohydride, 0.87ppm (GM) at synthetic rubber/resins and 0.13ppm (GM) Glue. We found that the highest exposure process for both the TWA and STEL samples was PS script process. Two samples exceeded 100ppm as short term exposure limit of Ministry of Employment and Labor(MOEL). Conclusions: Characteristic of STEL concentration for THF is considerably different from TWA concentration in workplaces because workers could exposure high concentration of THF in a moment when they work irregularly schedule. So exposure controls for momentary works have to be prepared, and considered the skin absorption and inhale of THF.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.3
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• pp.170-179
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• 2017

Objectives: This study aims to investigate the occupational radiation exposures of emergency medical technicians(EMTs) in emergency medical centers in Korea. The results will provide a basis for developing prevention programs to minimize adverse health effects relating to radiation exposure among emergency medical technicians working in this area. Methods: Radiation exposure doses were measured for twenty-two EMTs working in six emergency medical centers. Thermo Luminescent Dosimeters(TLD) were placed on three representative body parts, including chest, neck, and a finger. Measurements were conducted over the entire working hours of the participants for foor weeks. Dosimeters were analyzed according to a standard method by a KFDA-designated lab. Detection rate, annual radiation exposure dose, and relative levels to dose limit were derived based on the measured doses from the dosimeters. SPSS/Win 18.0 software(IBM, US) was used for statistical analysis. Results: Detection rates were 45.5%, 36.4%, and 45.5% for the dosimeters sampled from chest, neck, and a finger, respectively. The average annual doses were $2.39{\pm}3.44mSv/year$(range 0.38-10.0 mSv/year) for the chest, $2.72{\pm}3.05mSv/year$(2.00-11.34) for the neck, and $20.98{\pm}17.57mSv/year$(1.25-53.50) for the hand dose. The average annual eye dose was estimated to $3.61{\pm}2.37mSv/year$(1.50-8.34). The exposure dose levels of EMTs were comparable to those of radiologists, who showed relatively higher radiation dose among health care workers, as reported in another study. Conclusions: EMTs working in emergency medical centers are considered to be at risk of radiation exposure. Although the radiation exposure dose of EMTs does not exceed the dose limit, it is not negligible comparing to other professionals in health care sectors.

• Journal of Environmental Health Sciences
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• v.45 no.3
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• pp.258-266
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• 2019

Objectives: In this study, blood lead was analyzed using graphite furnace atomic absorption spectrometry (GF-AAs) and inductively coupled plasma mass spectrometry (ICP-MS). We tried to examine the difference and consistency of the analytical values and the applicability of the analytical method. Methods: We selected 57 people who agreed to participate in this study. After confirming the linearity of the calibration standard curves in GF-AAs and ICP-MS, the concentrations of lead in quality control material and samples were measured, and the degree of agreement was compared. Results: The detection limit of the ICP-MS was lower than that of GF-AAs. The coefficient of variation of reference materials was shown to be stable in the ICP-MS and GF-AAs. When the correspondence between the two equipments was verified by bias of the analysis values, a concordance was shown, and approximately 98% of the ideal reference lines were present within ${\pm}40%$ of the deflection. Conclusion: GF-AAs showed high sensitivity to single heavy metal analysis, but it took much time and showed higher detection limit than ICP-MS. Therefore, it would be considered necessary to switch to ICP-MS analysis method, considering that the level of lead exposure is gradually decreasing.

• Tunnel and Underground Space
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• v.7 no.4
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• pp.310-322
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• 1997

New limits of comfort boundary, psychological damage boundary and exposure limit for building residents by continuous and vibration are suggested. These limits are derived from the ISO 2631 and DIN 4150 regulations. A reasonable method to evaluate damages by vibrations is also suggested using the "total over-exposure of vibration" concept.; concept.

• Safety and Health at Work
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• v.7 no.1
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• pp.63-71
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• 2016

Background: Construction painters have not been studied well in terms of their hazards exposure. The objective of this study was to evaluate the exposure levels of total volatile organic compounds (TVOCs) for painters in the construction industry. Methods: Activity-specific personal air samplings were carried out in three waterproofing activities [polyurethane (PU), asphalt, and cement mortar] and three painting activities (epoxy, oil based, and water based) by using organic-vapor-monitor passive-sampling devices. Gas chromatograph with flame ionization detector could be used for identifying and quantifying individual organic chemicals. The levels of TVOCs, by summing up 15 targeted substances, were expressed in exposure-index (EI) values. Results: As arithmetic means in the order of concentration levels, the EIs of TVOCs in waterproofing works were 10.77, 2.42, 1.78, 1.68, 0.47, 0.07, and none detected (ND) for indoor PU-primer task, outdoor PU-primer task, outdoor PU-resin task, indoor PU-resin task, asphalt-primer task, asphalt-adhesive task, and cement-mortar task, respectively. The highest EI for painting works was 5.61 for indoor epoxyprimer task, followed by indoor epoxy-resin task (2.03), outdoor oil-based-spray-paint task (1.65), outdoor water-based-paint task (0.66), and indoor oil-based-paint task (0.15). Assuming that the operations were carried out continuously for 8 hours without breaks and by using the arithmetic means of EIs for each of the 12 tasks in this study, 58.3% (7 out of 12) exceeded the exposure limit of 100% (EI > 1.0), while 8.3% (1 out of 12) was in 50e100% of exposure limit (0.5 > EI > 1.0), and 4 tasks out of 12 were located in less than 50% of the limit range (EI < 0.5). Conclusion: From this study, we recognized that construction painters are exposed to various solvents, including carcinogens and reproductive toxins, and the levels of TVOC concentration in many of the painting tasks exceeded the exposure limits. Construction workers need to be protected from chemical agents during their painting works by using personal protective devices and/or work practice measures. Additional studies should focus on the exposure assessment of other hazards for construction workers, in order to identify high-risk tasks and to improve hazardous work environments.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.3
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• pp.375-383
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• 2023

Objectives: Coal-fired power plants feature diverse working conditions, including multi-layered employment structures and irregular work cycles due to outsourcing and non-standardized tasks. The current uniform occupational environment measurement systems have limitations in accurately assessing and evaluating these varied conditions. This study aims to propose alternative measurement and assessment strategies to supplement existing methods. Methods: Major domestic coal-fired power plants were selected as the study targets. To prepare for the study and establish strategies, work processes were identified and existing occupational environment measurement results were compared and analyzed. The study proceeded by employing three strategies: specific exposure groups (SEGs) measurement, continuous monitoring, and supplementary measurements, which were then compared and discussed. Results: Previous exposure index evaluations (5,268 cases) indicated that crystalline silica, a type of respirable particulate matter, had detection limits below the threshold (non-detectable) in 82.6% (4,349 cases) of instances. Exposures below 10% of the exposure limit were observed at a very low concentration of 96.1%. Similar exposure group measurements yielded results where detection limits were below the threshold in 38.2% of cases, and exposures below 10% of the limit were observed in 70.6%. Continuous monitoring indicated detection limits below the threshold in 12.6% of cases, and exposures below 10% of the limit were observed in 75.6%. Instances requiring active workplace management accounted for more than 30% of cases, with SEGs at 11.8% (four cases), showing a higher proportion compared to 3.0% (four cases) in continuous monitoring. For coal dust, exposures below 10% of the limit were highest in legal measurements at 90.2% (113 cases), followed by 74.0% (91 cases) in continuous monitoring, and 47.0% (16 cases) in SEGs. Instances exceeding 30% were most prevalent in SEGs at 14.7% (five cases), followed by legal measurements at 5.0% (eight cases), and continuous monitoring at 2.4% (three cases). When examining exposure levels through arithmetic means, crystalline silica was found to be 104.7% higher in SEGs at 0.0088 mg/m³ compared to 0.0043 mg/m³ in continuous monitoring. Coal dust measurements were highest in SEGs at 0.1247 mg/m³, followed by 0.1224 mg/m³ in legal measurements, and 0.0935 mg/m³ in continuous monitoring. Conclusions: Strategies involving SEGs measurement and continuous monitoring can enhance measurement reliability in environments with irregular work processes and frequent fluctuations in working conditions, as observed in coal-fired power plants. These strategies reduce the likelihood of omitting or underestimating processes and enhance measurement accuracy. In particular, a significant reduction in detection limits below the threshold for crystalline silica was observed. Supplementary measurements can identify worker exposure characteristics, uncover potential risks in blind spots of management, and provide a complementary method for legal measurements.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.4
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• pp.215-221
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• 2011

Objectives: This study was conducted to evaluate the exposure level of hazardous chemical agents for dental technicians in Ulsan. Methods: We measured airborne total dusts and metals such as Nickel, Manganese, Cobalt, and Chromium in 10 dental laboratories by the NIOSH Methods 0500 and 7300, respectively. Methyl methacrylate (MMA), a key ingredient in acrylic resin, was also monitored using passive samplers for long-term sampling and Tenax tubes for short-term sampling. Results: Measured levels of all items were below 10% of the Korean exposure limit except for Nickel. The geometric mean concentration and geometric standard deviation of total dust, Nickel, and MMA were $0.14mg/m^3$ (2.16), $165.3{\mu}g/m^3$ (3.31), and 0.2 ppm (2.5) respectively. Airborne Nickel concentration of two dental laboratories exceeded the exposure limit ($1000{\mu}g/m^3$). The major emission sources of Nickel were metal trimming and casting processes. Conclusions: We found that Nickel, a carcinogen, should be controled most urgently to protect dental technicians.

• Safety and Health at Work
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• v.7 no.2
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• pp.150-155
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• 2016

Background: Shipbuilding involves intensive welding activities, and welders are exposed to a variety of metal fumes, including manganese, that may be associated with neurological impairments. This study aimed to characterize total and size-fractionated manganese exposure resulting from welding operations in shipbuilding work areas. Methods: In this study, we characterized manganese-containing particulates with an emphasis on total mass (n = 86, closed-face 37-mm cassette samplers) and particle size-selective mass concentrations (n = 86, 8-stage cascade impactor samplers), particle size distributions, and a comparison of exposure levels determined using personal cassette and impactor samplers. Results: Our results suggest that 67.4% of all samples were above the current American Conference of Governmental Industrial Hygienists manganese threshold limit value of $100{\mu}g/m^3$ as inhalable mass. Furthermore, most of the particles containing manganese in the welding process were of the size of respirable particulates, and 90.7% of all samples exceeded the American Conference of Governmental Industrial Hygienists threshold limit value of $20{\mu}g/m^3$ for respirable manganese. Conclusion: The concentrations measured with the two sampler types (cassette: total mass; impactor: inhalable mass) were significantly correlated (r = 0.964, p < 0.001), but the total concentration obtained using cassette samplers was lower than the inhalable concentration of impactor samplers.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.12 s.105
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• pp.1327-1331
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• 2005

This Paper addresses what amount of whole-body vibration is exposed to Korean pilots of UH60 helicopters during their mission flight. To measure the expose4 whole-body vibration, the 12-axis whole-body vibration measurement system was used. It enables the direct measurement of whole-body vibration exposed from the body contact area consisting of the feet, hip and back. The measured 12-axis vibration signals were used to evaluate the vibration comfort level experienced by the pilots of UH60 helicopters. The evaluated vibration comfort level is found to be closeto 0.74-0.79m/s, which is equivalent to the semantic scale of 'fairly uncomfortable'. To assess the health effects of whole-body vibration exposed to Korean pilots of UH60 helicopters during their mission flight, the rms-based and VDV(vibration dose value)-based evaluation schemes, recommended by ISO 2631-1:1977, were exploited in this work. The evaluated results indicate that Korean pilots cannot avoid the fatigue-decreased proficiency limit after two-hour continuous flight. The whole-body vibration level exposed from the UH60 helicopters during continuous 10-hours mission flight is found to reach to the vibration exposure limit.

• YAKHAK HOEJI
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• v.55 no.2
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• pp.81-90
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• 2011

Most antineoplastic agents are nonselective in their mechanism of action, affecting noncancerous as well as cancerous cells, and resulting in acute effects such as irritation of mucous membranes and chronic effects such as genotoxicity, teratogenicity, and carcinogenicity. Healthcare workers occupationally exposed to antineoplastic agents are at risk. The present study aimed to develop and apply methods to monitor occupational exposure to antineoplastic agents, using cyclophosphamide (CP) as the model compound. To monitor environmental and biological exposure, potentially contaminated surfaces were wiped and 24 hour urine samples were collected from workers. Liquid chromatography combined with tandem mass spectrometry was performed, with a limit of detection of 0.05 ng/ml. Measurable amounts of CP were detected on 92% of the sampled surfaces, with a geometric mean of 175.22 $ng/m^2$. Despite the environmental contamination of the model compound, CP was below the detection limit in all urine samples. If workplace contamination cannot be completely avoided, it is importance to reduce exposure to the lowest possible levels. To this aim, efforts to minimize occupational exposure along with biological and environmental monitoring are required. The standardized sampling techniques, and specific and sensitive analytical methods reported in this study may be helpful in assessing occupational exposure and devising strategies to reduce exposure.