• 한국산업보건학회지
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• 제3권2호
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• pp.204-212
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• 1993

This study was conducted to evaluate ventilation efficiency of 4-stage slot hood by variation of slot width, flow rate, hood size and baffle size. The slot velocity, control velocity and plenum velocity were related to slot width and the distance between source of contamination and hood. The results obtained from laboratory experiment for local exhaust ventilation systems were as follows ; 1. When slot widths were constant(equally changed) and the velocity was 6-10 m/s, the slot velocity from 1st slot to 4th slot gradually decreased. As the slot width-to-slot length ratio(WLR) decreased, the slot velocity of each stage increased. But if WLR value was less than 0.04, the slot velocity decreased. 2. When slot velocity exceeded 10 m/s with constant slot widths, the slot velocity of each stage was uniform. 3. When the slot velocity was uniform within 10 m/s and the first slot width was 14-20 mm, the slot width ratio between 1st slot and each of three other slots were 1, 1.25, 1.5 and 3.0, respectively. 4. The slot and plenum velocity were uniform when exhaust flow rate changed from 14 to $19m^3/min$ and there were no hood splitter vanes. 5. When the slot velocity at each stage was uniform, the control velocity at site 30 cm away from hood No.2 increased from 0.15-0.30 to 0.25-0.45 m/s and the control distance from 20 to 30 cm(about 1.5 times).

• 한국산업보건학회지
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• 제7권1호
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• pp.3-18
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• 1997

This study was conducted to evaluate desorption efficiencies by types of desorption solvent for polar and non-polar organic compounds collected on activated charcoal tubes. Analytes tested were toluene, m-xylene, isobutyl alcohol, n-butyl alcohol, cellosolve acetate, and butyl cellosolve. Three different concentration levels of spiked sample were made. Types of cosolvent mixed with the main solvent, $CS_2$, were methanol, pentanol, and dimethylformamide (DMF) and the cosolvent for methylenechloride was methanol. The amounts of cosolvent added to the main solvent were 1, 5, and 10% by volume (v/v%), respectively. The results were as follows: 1. For all mixed solvents except 1% methanol and 1% pentanol with $CS_2$, desorption efficiency significantly increased, compared with that of $CS_2$ alone. 2. Desorption efficiency increased by increasing analyte loading on charcoal tube regardless of mixed solvents used and the material polarity. 3. For all cosolvents mixed with $CS_2$ by 1% and 5% volume, desorption efficiency for non-polar compound was significantly higher than that of polar compound. For the 10% mixed solvents and the methylenechloride mixed with methanol, the results were opposite. 4. The lowest mean percent bias of 4.79% was obtained from the 5% DMF-$CS_2$ mixed solvent, followed by 4.82% from the 10% DMF-$CS_2$ solvent while the highest bias of 23.26% was from the solvent of $CS_2$ alone. Based on the results of this study, in order to increase desorption efficiency, it is recommended to add such cosolvents as methanol, pentanol, and DMF to $CS_2$, preferably 5% by volume for analyzing polar compounds collected in charcoal tubes.

• 한국식품위생안전성학회지
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• 제28권2호
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• pp.95-98
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• 2013

Streptococcus suis (S. suis) is a major swine pathogen and an emerging zoonotic agent and is an increasing public health problem across Asia. The present study was undertaken to estimate the antibacterial effect of GR extract and therapeutic effect of GR extract against S. suis infection in mice. At the concentration of GR extract 2.5 mg/ml, the antibacterial effect was not shown on S. suis. However, the antibacterial effect against S. suis was observed at the concentration of GR extract 5.0 mg/ml. Oral administration of GR extract at the dose of 10 mg/kg showed a therapeutic effect for S. suis infected BALB/c mice. The mortality of GR extract-treated mice at the concentration of 5, 10 and 20 mg/kg was 80%, 70%, and 50% at 12 days, respectively, while that of untreated mice was 100% at 8 days after a lethal dose of S. suis infection. The results of our study strongly indicate that GR extract has potential as an effective for S. suis infection in mice.

• 한국산업보건학회지
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• 제24권3호
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• pp.256-262
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• 2014

Objectives: The purpose of this study was to identify the major volatile organic compounds generated during extrusion work with nylon 66 resin and evaluate causes of discomfort among extrusion workers. Methods: A thermal decomposition experiment using nylon 66 resin collected at a worksite was conducted in the laboratory. Based on hazards identified through the thermal decomposition experiment, the exposure levels of the workers were evaluated. Results: The major decomposition products were formaldehyde, acetaldehyde, aniline, cyclopentanone and diphenyl amine. These materials were identical to those sampled in the extrusion booth. The sources of the annoying smells, about which the workers had complained, were formaldehyde, aniline, diphenyl amine, and other hazards in the vapor and fine particles produced by the extrusion work. Formaldehyde, acetaldehyde, and aniline were detected from air samples among workers involved in extrusion work. However, the concentration levels were much lower than Korean occupational exposure limits. The average concentration levels of formaldehyde, acetaldehyde, and aniline were 0.0120 ppm, 0.0036 ppm and 0.0006 ppm, respectively. Conclusions: The extrusion process at around $300^{\circ}C$ thermally decomposes the nylon 66 resin, emitting formaldehyde, aniline, and other hazards, which might have made workers uncomfortable due to their smells. The workers exposure levels to volatile organic compounds were far lower than Korean occupational exposure limits. However, since formaldehyde is a human carcinogen and acetaldehyde and aniline are also confirmed animal carcinogens, it is recommended that exposure levels should be maintained at a minimum level.

• 한국산업보건학회지
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• 제29권4호
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• pp.582-589
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• 2019

Objectives: Although active pulmonary tuberculosis(active PTB) is manifested as one of the complications of pneumoconiosis, attacks of active PTB among patients with pneumoconiosis is still unexplored. The objective of the present study was to identify the attack rate of active PTB among workers in dusty environments who were diagnosed with pneumoconiosis. Methods: The study was performed using the results of the Pneumoconiosis Examination Council's assessment from the Korea Workers' Compensation and Welfare Service(KCOMWEL) database between January 1, 1984 and December 31, 2017. Pneumoconiosis was defined as Category 1 or more in the radiological findings of pneumoconiosis. Active PTB was defined as a positive result for active PTB in the results of the Pneumoconiosis Examination Council's assessment. Results: A total of 37,946 workers in dusty environments who received a health examination for diagnosing pneumoconiosis between January 1, 1984 and December 31, 2017 were selected as study subjects. The attack rate of active TB among subjects who were diagnosed with pneumoconiosis and those who were diagnosed without pneumoconiosis were 8.5% and 1.4%, respectively. In the multivariate logistic analysis including age, sex, radiological findings, complications, male[odds ratio(OR), 2.0; 95% confidence interval(CI), 1.4-3.1] and pneumoconiosis(OR, 6.5; 95% CI, 5.7-7.4) were associated with an increased risk of developing active PTB. Conclusions: The present study determined that dusty workers who were diagnosed with pneumoconiosis had a high rate of active PTB compared to TB patients and patients who were diagnosed with silicosis. Therefore, in addition to silicosis, it is necessary to include pneumoconiosis among the high-risk groups for TB.

• 한국식품위생안전성학회지
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• 제27권3호
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• pp.290-294
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• 2012

Vibrio spp. and Streptococcus spp. have caused a considerable disease of farmed fish and economic loss in fish farming and seafood industry. In this study, the efficacy of an aquatic disinfectant tablet composed to calcium hypochlorite was evaluated against V. anguillarum and S. iniae. A bactericidal efficacy test by broth dilution method was used to determine the lowest effective dilution of the disinfectant following exposure to test bacteria for 30 min at $4^{\circ}C$. An aquatic disinfectant tablet and test bacteria were diluted with distilled water (DW), hard water (HW) or organic matter suspension (OM) according to treatment condition. V. anguillarum on the DW, HW and OM condition was completely inactivated with 16,000 15,000 and 13,000 fold dilutions of the disinfectant, respectively. On the DW, HW and OM condition, S. iniae was absolutely inactivated with 17,000 16,000 and 14,000 fold dilutions of the disinfectant, respectively. As an aquatic disinfectant tablet possesses bactericidal efficacy against fish pathogenic bacteria such as V. anguillarum and S. iniae this disinfectant solution can be used to control the spread of fish infective bacterial diseases.

• 한국산업보건학회지
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• 제22권3호
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• pp.235-243
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• 2012

Objectives: The purpose of this study is the work environment management method through risk assessment and investigation of the work place that deals with Ammonium nitrate, based on information in and outside the country. Methods: This study suggests method of work environment management through risk assessment and investigation of the work place that deals with Ammonium nitrate, and finds out cases of Ammonium nitrate causing hazard, danger and health risk, based on literature investigation. Results: Rats exposed repeatedly to $LD_{50}$ 2,217 mg/kg(rat), $LC_{50}$ 88.8 mg/L(rat, skin) which cause high level of skin irritation, reported 1 $mg/m^3$ of NOAEL, while LOAEL was less than 100 mg/kg for the rats orally administered with the $LD_{50}$ 2,217 mg/kg(rat), $LC_{50}$ 88.8 mg/L(rat, skin), for 13 weeks. Domestically 31,640 ton/y of ammonium nitrate has been used in 22 workplace and the result of workplace assessment was 0.0171-0.9983 $mg/m^3$. ADD was 8.77-59.63 ${\mu}g/kg-day$ according to the exposure scenario. In other words the result of the risk assessment goes beyond the 'standard 1'. Conclusions: Ammonium nitrate creates a high level of irritation and toxicity when coming in breathe it or contact with skin, and is classified as category3 of GHS and specific target organ toxicant (irritating respiratory system). Exposure level at work places needs to be maintained under $1mg/m^3$, to prevent workers from being damaged.

• 한국산업보건학회지
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• 제28권3호
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• pp.273-282
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• 2018

Objectives: Dustiness of nanomaterials is considered as exposure index of essential material. Research on dustiness of nanomaterial is needed to control exposure in workplaces. Method: Dustiness measurement using vortex shaker were installed in the laboratory. Nanomaterials, 1 g, was put in the glass test tube and shaked using vortex shaker. Aerosol dispersed was measured using scanning mobility particle sizer(SMPS) and optical particle counter(OPC). Mass concentration using PVC filter and cassette was measured and TEM grid sampling was conducted. Total particle concentration and size distribution were calculated. Image and chemical composition of particles in the air were observed using transmission electron microscopy and energy dispersive X-ray spectrometer. Eleven different test nanomaterials were used in the study. Results: Rank of mass concentration and particle number concentration were coincided in most cases. Rank of nanomateirals with low concentration were not coincided. Two types of fumed silica had the highest mass concentration and particle number concentration. Indium tin oxide, a mixture of indium oxide and tin oxide, had high mass concentration and particle number concentration. Indium oxide had very low mass concentration and particle number concentration. Agglomeration of nanoparticles in the air were observed in TEM analysis and size distribution. In this study, mass concentration and particle number concentration were coincided and two index can be used together. The range of dustiness in particle number concentration were too wide to measure in one method. Conclusion: Particle number concentration ranged from low concentration to high concentration depend on type of nanomaterial, and varied by preparation and amount of nanomaterial used. Further study is needed to measure dustiness of all nanomaterial as one reference method.

• 한국산업보건학회지
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• 제29권2호
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• pp.217-225
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• 2019

Objectives: The aim of this study is to evaluate the quality management systems of domestic asbestos survey and monitoring service providers and the relationships with the number of licenses or designations and sales performances. Methods: Data on quality management systems were collected by assessors who were assigned by the Korea Occupational Safety and Health Agency(KOSHA) during a pilot evaluation program for designated asbestos survey and monitoring service providers in 2016 using evaluation criteria developed by KOSHA. Basic characteristics, evaluated scores, and sales performance were gathered and statistically analyzed. Results: The median and arithmetic mean of the total scores were 0.64 and 0.66. Evaluation fields that scored highly with the highest percentages were sales performance, installation and availability of equipment, compliance with the mandatory minimum number of airborne samples, laboratory independence, and results of proficiency analytical testing, in that order. Evaluation fields that received low marks with the highest percentages were the training of personnel, blank field samples, calibration of flow rates, preliminary check and visual inspection of the work area prior to the clearance test, and review and approval of final reports, in that order. Comparison of normalized scores between service providers registered for asbestos and other tasks and those designated for only asbestos showed significant differences in their evaluated scores. Sales performance did not show a positive correlation with evaluated scores. Conclusions: The quality management systems of domestic asbestos survey and monitoring service providers were poor. High scores were recorded mostly in evaluation fields related to regulatory requirements. Low scores were recorded mostly in evaluation fields related to documentation and recordkeeping. Considering the low influence of quality on sales performance, the government needs to evaluate the quality management of asbestos survey and monitoring service providers and provide the results to public in order to address their low levels of quality management.

• 한국산업보건학회지
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• 제5권1호
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• pp.8-15
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• 1995

사람의 독성 영향을 평가하는데는 생체 시료중 금속의 분석이 중요한 역할을 한다. 우리 나라는 최근에 산업보건 분야에서 이 문제의 필요성이 제기되어 법적인 정도관리 제도를 도입하였다. 연은 특수건강 진단과 산업위생 정도관리 프로그램에서 표준적인 금속으로 이용된다. 과거 20 여년 동안 연중독은 중금속 중독증 발생율이 가장 높았으며 따라서 산업보건 전문기관들은 혈중연 분석의 능력은 필수적인 것으로 되어 왔다. 또한 혈중연은 연 폭로를 평가하는데 가장 중요한 지표이므로 신뢰성과 정확한 분석이 항상 요구된다. 따라서 본 연구는 우리 나라에서 비교적 잘 알려진 산업보건기관에서 혈중연 분석의 실험실간 측정치의 변동을 평가하기 위하여 축전지 제조공장의 68명 연폭로 근로자로부터 2 ml씩 2개의 시료를 채취하여 그 하나는 순천향대 산업의학연구소(SIIM)에서 분석하고 40개의 시료는 C 대학 산업의학연구소(CIIM), 그리고 나머지 28개의 시료는 일본 K 노동위생기술쎈타(JOHC)에서 분석하여 비교하였으며, 한편 일본 전국노동위생연합회(JFOHO)에서 정도관리용 우혈을 농도별로 6종을 구입하여 우리나라 정도관리 프로그램에 참여하고 있는 C 대학 산업의학연구소, 일본 K 노동위생기술쎈타, Y 대학 산업의학연구소, S 대 환경보건과, D 연구소등 6개 기관에서 분석한 결과를 비교하여 다음과 같은 결과를 얻었다. 1. 순천향대 산업의학연구소와 국내 C 대학 산업의학연구소간 혈중연 농도별 분석결과는 평균값에서 유의한 차이가 없었으며 상대표준편차도 3% 미만인 것으로 나타났으며, 일본 K 노동위생기술쎈타와는 평균값에서 역시 유의한 차가 없었으며 상대표준편차는 최고 6.84% 였다. 2. 순천향대 산업의학연구소와 국내 C 대학 산업 의학연구소간 혈중연 농도별 분석결과가 15% 이하의 차이를 나타낸 시료의 수는 40개중 35개로 87.5%의 일치율을 나타내었으며, 일본 K 노동위생기술쎈타와는 28개 시료중 22개로 78.6%의 일치율을 나타내었다. 3. 순천향대 산업의학연구소의 결과를 종속변수로 그리고 국내 C 대학 산업의학연구소간의 분석치를 독립변수로 하였을 때 단순회귀식은 순천향 = 2.19 + 0.9243 C 대학(p=0.0001), 상관계수는 r = 975(p =0.0001)였으며, 일본 기관과는 순천향 = 1.91 + 0.9794 K 일본(p=0.0001), 상관계수 r = 0.965(p=0.0001)였다. 4. 일본 정도관리시료의 공인 값과 본 연구에서 이들 시료를 분석한 기관들 간의 분석치에 대한 단순회귀식의 설명력(R2)은 모두 0.99 이상이었으며 일본 정도관리 시료의 공인 값을 종속변수로 하고 국내 및 일본 기관들의 정도관리 시료 분석치를 독립변수로 하였을 때 기울기는 0.972에서 1.153으로 정체적으로 양호한 일치율을 나타내었다.