• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.2
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• pp.131-144
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• 2006

For the purpose of preparing the fundamental data on working environment of small scale manufacturing industries and preventing the occupational diseases of workers in these industries, authors surveyed the status of working environment to several chemical substances and physical agents by types of industry and types of process in the small scale manufacturing industries with less than five workers in Gimhae including 235 workplaces, 14 types of industry and 25 types of process from January 2002 to December 2004. This measurement method was work environment measurement method (established in Ministry of Labor, Korea), analytical methods (2nd Ed.) of Occupational Safety and Health Administration (OSHA) and manual of analytical methods (4th Ed.) of National Institute for Occupational Safety and Health (NIOSH) and collected data was analyzed by using SPSS 10.0 for windows, the results were as follows: 1. Noise generated in 14 types of industry and 22 types of process. an actual level of mean exposure (90.7 dB(A)) exceeded threshold limit values (TLVs) in manufacture of other transport equipment. An actual level of mean exposure (90.2dB) exceeded TLVs in the process of wire-drawing and 90.4dB in the process of wire-stranding. 2. Dusts of type I, II, III were generated in 9 types of industry and 8 types of process. Its mean concentration did not exceed TLVs. 3. Heavy metals (Pb, Mn, Cr, Ni) were generated in 7 types of industry and 7 types of process. Its mean concentration did not exceed TLVs. 4. 16 kinds of organic solvents were generated in 11 types of industry and 6 types of process. Its mean concentration did not exceed TLVs. As the above results, chemical substances and physical agents were generated in the several different types of industry and process of the manufacturing industry with less than five workers, and only mean level of noise was exceeded TLVs. In case of exceeding threshold limit values, improvement of work environment is actively needed, and work environment management should be performed continuously for prevention of an occupational diseases and work related diseases.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.2
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• pp.185-195
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• 2020

Objectives: The purpose of this study was to analyze noise exposure levels and the rate of exceedance of exposure limits in workplaces from a 2015 measurement of working environments according to area, industry, and scale of workplace and to determine changes compared to the past. Methods: Among the 408,875 measurements of noise in working environments from 27,030 workplaces in 2015, 16,359 workplaces that were linked to special health examination data were selected as the subjects of this study. The eight-hour corrected measurements and geometric mean values of the individual noise measurements of the workplaces were used to calculate noise exposure levels and the exceedance rate of exposure limits. Results: The average noise exposure level of the overall workplaces making up the subjects of this study was 83.6 dBA, and the exceedance rate of exposure limits was 15.1%. At least half of the noise measurements exceeded the exposure limits in 13.7% of the workplaces. Noise exposure levels were higher in the manufacturing industry and in smaller-scale workplaces. The exceedance rate of noise exposure limits was higher in the mining and manufacturing industries and in smaller-scale workplaces. Conclusions: Noise exposure has shown improvements compared to the past, but the exceedance rate of exposure limits was still high, and more than half of the workers were being exposed to noise of 85 dBA or higher. Therefore, it is necessary to make more active improvements in working environments in terms of noise exposure.

• Toxicological Research
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• v.33 no.4
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• pp.333-342
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• 2017

Ethyl formate, a volatile solvent, has insecticidal and fungicidal properties and is suggested as a potential fumigant for stored crop and fruit. Its primary contact route is through the respiratory tract; however, reliable repeated toxicological studies focusing on the inhalation route have not been published to date. Therefore, the present study was conducted to investigate the safety of a 90-day repeated inhalation exposure in rats. Forty male and 40 female rats were exposed to ethyl formate vapor via inhalation at concentrations of 0, 66, 330, and 1,320 ppm for 6 hr/day, 5 days a week for 13 weeks. Clinical signs, body weights, food consumption, urinalysis, hematologic parameters, serum chemistry measurements, organ weights, necropsy, and histopathological findings were compared between the control and ethyl formate-exposed groups. Locomotor activity decreased during exposure and recovered afterward in male and female rats exposed to 1,320 ppm ethyl formate. Body weight and food consumption continuously decreased in both sexes exposed to 1,320 ppm ethyl formate from week 1 or 3 compared with the control values. The increases in adrenal weight and decreases in thymus weight were noted in both sexes exposed to ethyl formate at 1,320 ppm. Degeneration, squamous metaplasia of olfactory epithelium in the nasopharyngeal tissue, or both were noted in the male and female rats at 1,320 ppm and female rats at 330 ppm ethyl formate. Taken together, our results indicate that ethyl formate-induced changes were not observed in male and female rats at 330 and 66 ppm, respectively. This indicates that exposure to ethyl formate at concentrations below 66 ppm for 90 days is relatively safe in rats. This is the first report of a full-scale repeated inhalation toxicity assessment in rats and could contribute to controlling occupational environmental hazards related to ethyl formate.

• Safety and Health at Work
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• v.10 no.1
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• pp.75-79
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• 2019

Background: Since the presence of a co-driver can be considered as a companion, partner, or friend for a driver through eliminating driver's loneliness, it plays a significant role in health and safety of drivers. The objective of this study was to investigate the effect of co-drivers on depression and occupational stress on male truck drivers. Methods: This study was an interventional case-control study. Seventy truck drivers were selected and divided into two groups: case (33 truck drivers with co-drivers) and control (37 truck drivers without codrivers). Two Goldberg depression inventories (for evaluating driver's depression) and the Karasek job content questionnaire (for evaluating driver's job stress) were used to collect data which were completed by interview. Results: The results showed that job content values for the case group were higher in all dimensions except job nature. The comparison of the percentages showed significant difference between two groups. Depression rate in drivers with co-driver is truly less than depression rate in drivers without co-driver. There was significant positive relationship between dimensions of job content and depression rate. Conclusion: According to the results of this study, it can be claimed that a co-driver decreases stress and loneliness of drivers, as well as increases work performance and job satisfaction, and, in turn, leads to a decrease in job-related depression.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.4
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• pp.350-358
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• 2022

Objectives: For chemical risk assessment in workplaces, it is necessary to determine a reference value through hazard assessment. In general, OEL (Occupational Exposure Limit) is used for this value. However, since chemicals with OEL were not enough, the concept of DNEL (Derived No Effect Level) was introduced in chemical safety assessment. In this study, the possibility and approach of applying DNEL for chemical risk assessment in domestic workplaces were investigated. Methods: The characteristics of OEL and DNEL were investigated. In addition, ACGIH TLV and GESTIS DNEL were compared and the corresponding scopes were analyzed among the chemical substances notified in South Korea. Results: OEL and DNEL are similar concepts reflecting reference values that should not be exposed based on health effects. While their evaluation and derivation are determined based on similar information and procedures, they may vary depending on the responsible actor, data availability, principles of judgment, and more. As a result of the comparative analysis of ACGIH TLV and GESTIS DNEL, it was confirmed that there is some correlation between TWA and DNEL. The conservatism of DNEL was around 50%. Additionally, it was found that the available range of DNEL among chemicals in South Korea is considerable. Conclusions: This study showed that DNEL can be applied when assessing the risk of chemical substances in domestic workplaces considering several regards. However, since this is not the same level as OEL, we have proposed a proper approach to carry out risk assessment step by step.

• Annals of Occupational and Environmental Medicine
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• v.34
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• pp.28.1-28.12
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• 2022

Background: Haenyeo is a woman who has the job of collecting seafood in the Jeju Sea at an average temperature of 13℃-14℃. The purpose of this study was to examine the cold acclimatization and occupational characteristics of Haenyeo through biomarkers such as orexin and irisin related to heat generation in the body. Methods: Twenty-one Haenyeo and 25 people with similar age, body type, and body mass index were selected as the control group (Control G). In the cold exposure experiment, a climate chamber was set to 5℃ and both feet were immersed in a 15℃ water tank for 30 minutes. Tympanic temperature (T_ty) and skin temperature (T_sk) were measured, and the mean body temperature (mT_b) was calculated. Blood samples were collected before and immediately after the examination. Orexin and irisin levels were analyzed. Results: Orexin levels were elevated after cold stimulation from 12.17 ± 4.44 to 12.95 ± 4.53 ng/mL (Haenyeo group [Haenyeo G], p < 0.01) and 10.37 ± 3.84 to 11.25 ± 4.02 ng/mL (Control G, p < 0.001). Irisin levels were elevated after cold stimulation from 4.83 ± 2.28 to 5.36 ± 2.23 ng/mL (Haenyeo G, p < 0.001) and 3.73 ± 1.59 to 4.18 ± 2.04 ng/mL (Control G, p < 0.001). The difference between Haenyeo G and Control G values in orexin and irisin appears not only in pre-exposure but also in post-exposure (p < 0.05). Conclusions: Our experimental results suggest that Haenyeo G were relatively superior in cold tolerance to Control G under cold exposure conditions. Haenyeo's cold acclimatization is due to the basic differences in pyrogens regarding body temperature control such as orexin and irisin. This means that Haenyeo are advantageous for cold survival.

• Safety and Health at Work
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• v.2 no.3
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• pp.236-242
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• 2011

Objectives: To determine the feasibility of predicting static and dynamic peak back-compressive forces based on (1) static back compressive force values at the lift origin and destination and (2) lifting speed. Methods: Ten male subjects performed symmetric mid-sagittal floor-to-shoulder, floor-to-waist, and waist-to-shoulder lifts at three different speeds (slow, medium, and fast), and with two different loads (light and heavy). Two-dimensional kinematics and kinetics were captured. Linear regression analyses were used to develop prediction equations, the amount of predictability, and significance for static and dynamic peak back-compressive forces based on a static origin and destination average (SODA) backcompressive force. Results: Static and dynamic peak back-compressive forces were highly predicted by the SODA, with R2 values ranging from 0.830 to 0.947. Slopes were significantly different between slow and fast lifting speeds (p < 0.05) for the dynamic peak prediction equations. The slope of the regression line for static prediction was significantly greater than one with a significant positive intercept value. Conclusion: SODA under-predict both static and dynamic peak back-compressive force values. Peak values are highly predictable and could be readily determined using back-compressive force assessments at the origin and destination of a lifting task. This could be valuable for enhancing job design and analysis in the workplace and for large-scale studies where a full analysis of each lifting task is not feasible.

• Safety and Health at Work
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• v.3 no.4
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• pp.287-293
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• 2012

Objectives: Metabolic syndrome has received attention as a risk factor for cardiovascular disease, with particular importance attached to visceral fat accumulation, which is associated with lifestyle-related diseases and is strongly correlated with waist circumference. In this study, our aim is to propose waist circumference cut-off values that can be used as a marker for fatty liver based on a sample of workers receiving health checkups in Japan. Methods: This study was conducted in a total of 21,866 workers who underwent periodic health checkups between January 2007 and December 2007. The mean age of the subjects was 47.4 years for men (standard deviation [SD]: 8.0) and 44.7 years for women (SD: 6.9). Evaluation included abdominal ultrasound and measurement of waist circumference, body mass index, fasting blood glucose, triglycerides, high-density lipoprotein cholesterol, and blood pressure. Results: Based on receiver operating characteristic curve analysis, the optimal waist circumference cut-off values were shown as 85.0 cm (sensitivity 0.72, specificity 0.69) for men and 80.0 cm (sensitivity 0.75, specificity 0.78) for women. Conclusion: Abdominal ultrasound is the most efficient means of diagnosing fatty liver, but this examination seldom occurs because the test is not routinely performed at workers' health checkups. In people found to have a high risk of fatty liver, recommendations can be made for abdominal ultrasound based on the waist circumference cut-off values obtained in this study. That is, waist circumference can be used in high risk individuals as an effective marker for early detection of fatty liver.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.2
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• pp.104-113
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• 2005

A variety of ergonomic assessment methods of lifting tasks known as a major cause of work-related lower back pain have been used. But there is a limited information in choosing the most appropriate assessment method for a particular job and in finding out strengths and weakness of the methods. The purpose of this study was to assess and compare the ergonomic risks of lifting tasks in a marine diesel engine production industry by three lifting ergonomic assessment tools widely used: the National Institute for Occupational Safety and Health(NIOSH) Revised Lifting Equation(NLE), the Washington Administrative Code 296-62-0517(WAC), and the Snook Tables. Lifting index(weight of load/Recommended Weight Limit) of NLE($LI_{NLE}$) was above 1 at 34 tasks(75.6%) of a total number of 45 lifting tasks. LI of WAC($LI_{WAC}$) was above 1 at 11 tasks(24.4 %). LI of Snook Table($LI_{Snook}$) was above 1 at 29 tasks(64.4%). Thus, LI was high in orders of $LI_{NLE}$ > $LI_{Snook}$ > $LI_{WAC}$. There were significantly high correlations among three Lls(p<0.01). The correlation coefficients between $LI_{NLE}$and the other three Lls($LI_{WAC}$ and $LI_{Snook}$) were r=0.93 and r=0.88, respectively. The linear regression equations were y = 0.444x + 0.11(r=0.93) between $LI_{NLE}$ and $LI_{WAC}$, y = 0.93x + 0.008(r=0.88) between LI(NLE) and $LI_{Snook}$. The LI values by WAC was significantly lower than those by the other tools. The compared features, strength and limitation among these tools were described in this paper.

• 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.