• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.281-292
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• 2014

Objectives: The aim of this case study is to verify the chemical exposure reductions for various chemicals by substituting the ingredients of raw materials in a polyurethane(PU) foaming industry. The PU foaming process was making various passenger car seats from chemicals such as toluene diisocinate(TDI), methylene bisphenyl isocyanate(MDI) and polyols. Methods: Basic process data and workers' health effects could be gathered by interviewing managers and reviewing previous exposure monitoring data. Amine, aldehyde and isocyanate chemicals were analyzed following the NIOSH-NMAM. Area sampling methods rather than personal sampling were introduced for this field investigation. Results: Two amines, triethylene diamine(TEDA) and N,N,N',N'-Tetramethyl-1,6- hexanediamine(TMHDA) were identified in raw polyol, cured PU foam and air. The average concentrations of TEDA and TMHDA showd less than 1 ppm by area sampling; however, that caused halovision among workers in PU-PAD process. Aldehydes and isocyanates were detected in the air while the concentrations were relatively low compare to occupational exposure limits. Successful raw material substitution from nonreactive amine to reactive amine could reduces air-borne amine and aldehyde levels by about 70%. Halovision had been disappeared successfully in the process. Conclusions: Several amines caused halovision among workers in PU-PAD process, especially during summer season in spite of relatively low levels. Combination of reactive amines into urethane foam could reduced vapor generation into air, which resulted in the elimination of eye troubles in the process.

• Safety and Health at Work
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• v.11 no.2
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• pp.235-240
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• 2020

Background: Cadmium exposure may induce chronic intoxication with renal damage. Silver soldering may be a source of cadmium exposure. Methods: We analyzed working environment measurement data and periodic health screening data from a small-scale silver soldering company with ten workers. Concentrations of cadmium in air from working environment measurement data were obtained. Concentrations of blood and urinary cadmium, urine protein, and urine β2-microglobulin (β2M) were obtained. The generalized linear model was used to identify the association between blood and urine cadmium and urine β2M concentrations. Clinical features of chronic cadmium intoxication focused with toxicological renal effects were described. Results: The mean duration of work was 8.5 years (standard deviation [SD] = 6.9, range = 3-20 years). Cadmium concentrations in air were ranged from 0.006 to 0.015 mg/㎥. Blood cadmium concentration was elevated in all ten workers, with a highest level of 34.6 ㎍/L (mean = 21.288 ㎍/L, SD = 11.304, range = 9.641-34.630 ㎍/L). Urinary cadmium concentration was elevated in nine workers, with a highest level of 62.9 ㎍/g Cr (mean = 22.151 ㎍/g creatinine, SD = 19.889, range = 3.228-62.971 ㎍/g creatinine). Urine β2M concentration was elevated in three workers. Urinary cadmium concentration was positively associated with urine protein concentration (beta coefficient = 10.27, 95% confidence interval = [4.36, 16.18]). Other clinical parameters were compatible with renal tubular damage. Conclusion: Cadmium intoxication may occur at quite low air concentrations. Exposure limit may be needed to be lowered.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.3
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• pp.224-234
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• 2012

Objectives: To assess the hazard of Korea chrysotile and anthophylite, fibers were analyzed for their physicochemical properties by transmission electron microscope equipped with energy dispersive X-ray spectrometer (TEM-EDS). Methods: To evaluate the biopersistence of 2 domestic asbestos, Sprague-Dawely rats were exposed to 2 mg asbestos by intratracheal instillation. Each asbestos (chrysotile ; $8,814,244{\times}10^6$ fibers/mg, average size $0.08{\mu}m{\times}4.39{\mu}m$, anthophyllite ; $5,182{\times}10^6$ fibers/mg, average size $0.95{\mu}m{\times}7.29{\mu}m$) were evaluated after a single intratracheal instillation. At times from 1 week to 4 weeks after exposure, the numbers of asbestos fivers in the bronchoalveolar lavage fluid and in the lung were calculated. Results: Anthophyllite fivers continuously have retained for 4 weeks but chrysotile fivers were rarely found at 4 weeks after exposure in the bronchoalveolar lavage fluid. Chrysotile fivers at 4 weeks after treatment were not observed but anthophyllite was easily observed in the lung with phase contrast microscopy. According to electron microscopic observation of asbestos in the lung, within 1 week after the administration of chrysotile fivers were decreased rapidly but anthophyllite fivers were very little change for 4 weeks. When chrysotile fivers have been lost Fe in 1 week, there were no significant changes in anthophyllite fivers in the lung. Conclusions: These findings indicate that after a long time exposure to chrysotile, asbestos bodies can not be found in the bronchoalveolar lavage fluid.

• Safety and Health at Work
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• v.10 no.1
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• pp.87-94
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• 2019

Background: Lead (Pb) exposure in shooting ranges has been reduced by various measures such as jacketed ammunition and lead-free primers. Nevertheless, this may lead to exposure to other metals, potentially resulting in adverse health effects. Methods: In a cross-sectional study, 35 subjects from seven different shooting ranges were studied: four shooting instructors, 10 police officers, 15 Special Forces, and six maintenance staff members. Metals and metalloids were determined in blood and urine by inductively coupled plasma-mass spectrometry. Results: The concentrations of most elements did not differ significantly between groups or compared to reference values, except for Sb and Pt in urine and Pb in blood. Mean values for Sb were considerably higher in urine from the Special Forces ($0.34{\mu}g/L$), the maintenance staff ($0.13{\mu}g/L$), and shooting instructors ($0.32{\mu}g/L$) compared to the police officers before shooting ($0.06{\mu}g/L$) and a Belgian reference value ($0.04{\mu}g/L$). For Pt, the Special Forces showed higher mean urinary concentrations ($0.078{\mu}g/L$) compared to a Belgian reference value (<$0.061{\mu}g/L$). Mean values for blood lead were markedly higher in the Special Forces ($3.9{\mu}g/dL$), maintenance staff ($5.7{\mu}g/dL$), and instructors ($11.7{\mu}g/dL$) compared to police officers ($1.4{\mu}g/dL$). One instructor exceeded the biological exposure index for blood Pb ($38.8{\mu}g/dL$). Conclusion: Since both Pb and Sb were found to be higher in shooting range employees, especially among frequent shooters, it is advisable to provide appropriate protective equipment, education, and medical follow-up for shooting range personnel in addition to careful choice of ammunition.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.263-271
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• 2014

Objectives: Along with the several cases of pulmonary disorders caused by exposure to indium that have been reported in Japan, China, and the United States, cases of Korean workers involved in processes that require handling of indium compounds with potential risk of exposure to indium compounds have also been reported. We performed biological monitoring for workers in various target manufacturing processes of indium, indium oxide, and indium tin oxide(ITO)/indium zinc oxide(IZO) in domestic factories. Materials: As biological exposure indices, we measured serum concentrations of indium using inductively coupled plasma mass spectrometry, and Krebs von den Lungen 6(KL-6) and surfactant protein D(SP-D) using enzyme-linked immunosorbent assays. We classified the ITO/IZO target manufacturing process into powdering, mixing, molding, sintering, polishing, bonding, and finishing. Results: The powdering process workers showed the highest serum indium level. The mixing and polishing process workers also showed high serum indium levels. In the powdering process, the mean indium serum concentration in the workers exceeded $3{\mu}g/L$, the reference value in Japan. Of the powdering, mixing, and polishing process workers, 83.3%, 50.0%, and 24.5%, respectively, had values exceeding the reference value in Japan. We suppose that the reason of the higher prevalence of high indium concentrations in powder processing workers was that most of the particles in the powdering process were respirable dust smaller than $10{\mu}m$. The mean KL-6 and SP-D concentrations were high in the powdering, mixing, and polishing process workers. Therefore, the workers in these processes who were at greater risk of exposure to indium powder were those who had higher serum levels of indium, as well as KL-6 and SP-D. We observed significant differences in serum indium, KL-6, and SP-D levels between the process groups. Conclusions: Five among the seven reported cases of "indium lung" in Japan involved polishing process workers. Polishing process workers in Korea also had high serum levels of indium, KL-6, and SP-D. The outcomes of this study can be used as essential bases for establishing biological monitoring measures for workers handling indium compounds, and for developing health-care guidelines and special medical surveillance in Korea.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.3
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• pp.202-212
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• 2021

Objectives: The reproductive health of female workers has been extensively investigated in South Korea and other countries worldwide. However, few studies have discussed the reproductive health of male workers. In this study, we reviewed the recent literature that reports on the effects of occupational exposure on the reproductive health of male workers and the health of their children. Methods: In May 2020 we used the PubMed search engine to search the literature over the last 10 years and chose case-control, cohort, and cross-sectional studies and reviews. We selected epidemiological studies that investigated the association between pre-pregnant occupational exposure and the reproductive health of male workers and the health of their children. We excluded case reports, non-epidemiological studies (animal experiments, cellular-level experiments, and similar articles), and studies that described postnatal occupational exposure. Results: We eventually selected 23 studies. The studies that included exclusively male workers reported that those employed in the agricultural sector or those exposed to pesticides showed lower blood levels of reproductive hormones and a high risk of lympho-hematopoietic system cancer in their children. Male workers exposed to complex organic solvents and organic compounds showed a high risk of poor semen quality, increased time to pregnancy, decreased blood levels of reproductive hormones, and a high risk of lympho-hematopoietic system cancer in their children. Male workers employed in occupations that involved significant social contact, or in the leather and livestock industries, and in occupations with high levels of exposure to lead and organic solvents showed a high risk of malignancies, including lympho-hematopoietic system cancer, neuroblastoma, and central nervous system tumors in their children. Studies that investigated both male and female workers reported that children of male smelters showed a high risk of premature birth, and children of male workers exposed to metals showed a high risk of hypospadias and cryptorchidism. Children of male welders and workers employed in the glass, ceramic, and tile industries showed a high risk of premature birth. Conclusion: The findings of this study will serve as basic data for further research on male workers' reproductive health and provide a scientific basis for the development of strategies to protect the reproductive health of males employed in high-risk occupations. Moreover, the results of this study may provide guidelines to improve the understanding of and knowledge on male workers' reproductive health.

• Safety and Health at Work
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• v.11 no.1
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• pp.33-40
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• 2020

Background: Exploratory study to investigate whether co-exposure to physical wrist stressors and chemicals is associated with carpal tunnel syndrome (CTS) in French male farmers and agricultural workers. Methods: Cross-sectional study of 711 men aged 30-65 years and working as either farmers or agricultural workers in 2009-2010 within a cohort covered by the French Agricultural Workers' and Farmers' Mutual Benefit Fund. CTS and exposure to physical wrist stressors and chemicals were assessed using a self-administered questionnaire. Associations between CTS and personal/medical factors, exposure to physical wrist stressors, exposure to chemicals, and co-exposure to physical wrist stressors and chemicals were studied using multivariate logistic regression models. Results: Forty-four men {5.6% [95% confidence interval (CI) 4.0-7.7]} reported that they had suffered from unilateral/bilateral CTS during the last 12 months. CTS was associated with age, current smoking [odds ratio (OR) = 2.1 (1.0-4.5)], and exposure to physical wrist stressors [OR = 2.6 (1.1-5.9)]. An association was found between CTS and co-exposure to physical wrist stressors and chemicals [OR = 3.3 (0.8-14.3), p = 0.044] in comparison with the no-exposure group. Conclusions: This exploratory study shows an association of CTS with exposure to biomechanical wrist stressors in male farmers and agricultural workers and suggests an association of CTS with co-exposure to physical wrist stressors and chemicals. Owing to the limitations of the study, this result must be confirmed by a prospective study with objective assessments of the outcome and exposure before drawing conclusions on the possible synergistic effects of mechanical stressors and chemicals on the impairment of the median nerve.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.05a
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• pp.31-34
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• 2003

The monitoring of genotoxic effect or oxidative DNA damage in workers exposed to hazardous materials is increasingly applied for hazard identification or risk assessment purposes in workplaces. The current generation of biomarkers has the potential to allow for the earlier detection of occupational disease, for the reduction of misclassification of exposure and outcome. (omitted)

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.2
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• pp.166-173
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• 2015

Objectives: The purpose of this study was to evaluate cobalt concentrations in airborne inhalable, total and respirable dust from manufacturing industries using cobalt. Methods: To compare cobalt concentrations, three types of dust samplers(a 37mm closed cassette sampler, Institute of Occupational Medicine(IOM) sampler, and Aluminum cyclone sampler) were used. The analysis of cobalt concentrations was conducted using AAs based on the NIOSH 7300 method. Results: The geometric mean of cobalt concentration in total dust was $1.47{\mu}g/m^3$, and the rate of excess of the Korean Occupational Exposure Limit(KOEL) was 10.0%. The geometric mean concentrations of cobalt in super alloy manufacturing industries were higher than those in plating industries, and molding operations showed higher exposure levels to cobalt than did other operations. Conclusions: The rate of cobalt concentration in inhalable dust from super alloy manufacturing industries exceeding the Workplace Exposure Limit(WEL) as recommended by the Health & Safety Executive(HSE) was 7.1%, which means proper work environmental management is required through wet work environments. Given that molding operations had higher cobalt concentrations, it is necessary to apply measures such as local exhaust for reducing airborne dust in cobalt manufacture industries.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.3
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• pp.209-216
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• 2012

Objectives: Polyurethanes are usually formed by the reactions of liquid diisocyanate components with liquid polyol resin components. Although polyurethanes have advantageous properties, such as their versatility, the manufacturing process generates diisocyanates, which can cause asthma and respiratory irritation in exposed workers. This study compared the differences in diisocyante concentrations between two different (molded foam and slabstock foam) polyurethane foam manufacturing methods. Materials and Methods: Active samples and direct reading samples of diisocyanates (MDI, TDI) were collected in five polyurethane foam manufacturing companies. Results: Workers' exposure concentrations of diisocyanate (GM: 4.078 ppb, range: 1.190~23.770 ppb) in a slabstock foam manufacturing company were much higher than those (GM: 0.011 ppb, range: 0.001~0.055 ppb) in molded foam manufacturing companies. The results of the direct reading samples of diisocyanate indicated that the rapid reaction zone of the slabstock foam processes emitted large amounts of diisocyanates. Conclusions: The exposure levels of diisocyanates for all molded foam workers were much lower than the occupational exposure standard (5 ppb); however, exposure levels for many slabstock foam workers exceeded the standard.