• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.1
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• pp.20-26
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• 2013

Objectives: This study was conducted to evaluate the health risk of workers exposed to butyl glycidyl ether to prevent them from developing occupational diseases. Methods: The workplaces that coat floor with epoxy were selected and the samples were collected and analyzed with NIOSH 1616 Method. We calculate workplace reference concentration using with NOAEL estimated by the study of Anderson et al. in 1978. Risk was calculated by the ratio of exposure to workplace reference concentration. Monte-Carlo simulation was performed to derivate the median, cumulative 90%, and cumulative 95% value by using Crystal Ball. Results: Butyl glycidyl ether is a skin, eye irritator and can result in central nervous system depression, allergic reaction. NOAEL was 38 ppm and workplace reference concentration was calculated as 0.73 ppm corrected with uncertainty factors. Geometric mean was 1.152 ppm and geometric standard deviation was 1.522 by the workplace environment measurement. The median, cumulative 90%, and cumulative 95% value of risk were calculated as 1.617, 1.934, and 2.092, respectively. Conclusions: Not only cumulative 90% and cumulative 95% value but also the median of risk is higher than 1.0 by the risk characterization, so it can do a lot of harm to workers. Therefore, the process of derivating workplace reference concentration and the appropriacy of the uncertainty factors should be re-examined.

• International Journal of Reliability and Applications
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• v.15 no.2
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• pp.85-98
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• 2014

Accelerated life testing (ALT) is a well famous technique in life testing and reliability studies, this is particularly used to induce so high stress leading to failure of the highly reliable units quickly under stipulated duration of time. The step-stress ALT is one of the systematic experimental strategy of ALT applied to fail the units in steps. In this article we focus on two important issues (i) necessity of life tests at higher steps with relevant causes (ii) to develop a new optimum test plan for 3-step SSALT under the modified cumulative exposure model proposed by Khamis and Higgins (1998). It is assumed that the lifetime of test units follows Rayleigh distribution and its scale parameter at constant stress level is assumed to be a log-linear function of the stress. The maximum likelihood estimates of the parameters involved in the step-stress ALT model are obtained. A simulation study is performed for numerical investigation of the proposed new optimum plan 3-step, step-stress ALT. The necessity of the life test units at 3-step step-stress is also numerically examined in comparison to simple step-stress setup.

• Safety and Health at Work
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• v.8 no.3
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• pp.315-317
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• 2017

We present the case of a 45-year-old man with a history of benzene exposure who developed splenic marginal zone lymphoma. For 6 years, he had worked in an enclosed space cleaning instruments with benzene. He was diagnosed with splenic marginal zone lymphoma 19 years after retirement. During his time of working in the laboratory in the 1980s, working environments were not monitored for hazardous materials. We indirectly estimated the cumulative level of past benzene exposure using job-exposure matrices and technical assumptions. Care must be taken in investigating the relevance of occupational benzene exposure in the occurrence of indolent B-cell lymphoma. Because of the long latency period and because occupational measurement data do not exist for the period during the patient's exposure, the epidemiological impact of benzene exposure may be underestimated.

• Clinical and Experimental Pediatrics
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• v.55 no.2
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• pp.35-41
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• 2012

Passive exposure to tobacco smoke significantly contributes to morbidity and mortality in children. Children, in particular, seem to be the most susceptible population to the harmful effects of environmental tobacco smoke (ETS). Paternal smoking inside the home leads to significant maternal and fetal exposure to ETS and may subsequently affect fetal health. ETS has been associated with adverse effects on pediatric health, including preterm birth, intrauterine growth retardation, perinatal mortality, respiratory illness, neurobehavioral problems, and decreased performance in school. A valid estimation of the risks associated with tobacco exposure depends on accurate measurement. Nicotine and its major metabolite, cotinine, are commonly used as smoking biomarkers, and their levels can be determined in various biological specimens such as blood, saliva, and urine. Recently, hair analysis was found to be a convenient, noninvasive technique for detecting the presence of nicotine exposure. Because nicotine/cotinine accumulates in hair during hair growth, it is a unique measure of longterm, cumulative exposure to tobacco smoke. Although smoking ban policies result in considerable reductions in ETS exposure, children are still exposed significantly to tobacco smoke not only in their homes but also in schools, restaurants, child-care settings, cars, buses, and other public places. Therefore, more effective strategies and public policies to protect preschool children from ETS should be consolidated.

• Journal of radiological science and technology
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• v.39 no.1
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• pp.27-33
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• 2016

The use of cardiac angiography (CA) and the interventional procedures is rapidly increasing due to the increase in modern adult diseases. Cardiovascular intervention (CI) is an examination method where radiation is applied to the same area for a long period, and thus may cause skin injury. In this study, we investigate the diagnostic reference level (DRL) of the cardiovascular intervention (CI) carried out by medical institutions and use it as a tool to reduce patient exposure dose. In this study, the DRL was set by acquiring information about the cumulative fluoroscopy time, cumulative fluoroscopy dose-area product (DAP), radiography DAP, cumulative DAP, air kerma, number of video clips, and the total number of images from the cardiac angiography and interventional procedures performed on 147 patients. The DAPs corresponding to the DRL of cardiac angiography(CA) and that of the interventional procedures were shown to be $44.4Gy{\cdot}cm2$ and $298.6Gy{\cdot}cm2$, respectively; the corresponding DRLs of fluoroscopy time were shown to be 191.5s and 1935.3s, respectively. A DRL is not a strict upper bound for radiation exposure. However, the process of setting, enacting, and reviewing the DRLs for the dose by medical institutions will contribute to a reduction in the unnecessary exposure dose of patients.

• Journal of the Korean Society of Radiology
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• v.13 no.3
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• pp.433-438
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• 2019

The medical institutions use radiation generating devices and radioactive isotopes to diagnose and treat patients. The patient transporter performs work in an environment that is more likely to be exposed to radiation when compared with the general public, such as inevitably entering the radiation management area for patient transfer, or transferring the isotope-administered patient at a short distance. For this reason, we conducted a study to determine the degree of exposure of the patient transporter. The 12 patient transporters working at Incheon A General Hospital are eligible. From April 1, 2019 to April 30, 2019, the dosimeter was used in the chest for one month and the accumulated dose was measured. The dosimeter used was a Optically Stimulated Luminescence Dosimetry (OSLD) and the dose reading was OSLD Microstar Reading System. As a result of cumulative dose measurement for one month, the average of the deep dose was 0.13 mSv and the surface dose was 0.13 mSv, and the cumulative dose for one month was multiplied by 12 to estimate the cumulative dose expectation As a result, the average of the deep dose and the surface dose were 1.52 mSv and 1.51 mSv, respectively. It is necessary to classify the patient transporter as a frequent visitor in order to measure and manage the exposure dose, increase the knowledge of protection against radiation through education and training, and prevent radiation trouble through medical examination.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.3
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• pp.157-170
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• 2008

Purpose: This prospective study was conducted to reveal the haematological index change by low level radiation exposure in radiological environment our hospital workers. Materials and Method: We gathered the cumulative dose by Thermoluminenscent Dosimeters (TLD) over 9-yr period and examined hematological index counts change (RBC, Hb, Platelet, WBC, Monocyte, Lymphocyte, Neutrophilic, Basophilic, Eosinophilic) both occupational workers and controls. Of a total 370 occupational workers and 335 controls were compared. Results: This analysis has led to the following general observations 1) The average cumulative dose in male and female were $9.65{\pm}15.2\;mSv$, $4.82{\pm}5.55\;mSv$ respectively. 2) In both male and female, there were very low relationship between occupation period and cumulative dose (r< ${\pm}0.25$). 3) Occupation period was more increased, in male, WBC counts decreased and increased workers, RBC counts decreased workers were more than controls group (p<0.05). In female, WBC counts decreased and increased workers and W-eosino counts decreased workers were more than controls group (p<0.01). 4) Cumulative dose was more increased, in male, W-Lympho counts decreased workers and Platelet counts deceased workers were more than controls group (p<0.05). In female, W-lympho counts decreased workers and RBC counts decreased workers were more than controls group (p<0.05). Conclusions: We can find some kinds of blood index abnormal distribution in occupational radiation workers by comparing with controls. Occupational workers cannot avoid radiation exposure, in spite of the control it. Actually low level radiation adverse effect occurred not dose but probability. So workers must always try to reduce exposure by ourselves, furthermore as long as possible the government should provide rapidly that national system on radiation control for worker's health.

• Journal of Environmental Impact Assessment
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• v.30 no.6
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• pp.413-424
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• 2021

Health impact assessment in the environmental impact assessment is conducted to determine whether to exceed the standard of each single substance and to establish appropriate reduction measures. In some development projects, although all substances in risk assessment meet the standard, exposure concentration is very close to it. However, considering the cumulative exposure of all substances, health effects are likely to occur considerably severer than those of individual substances, so it is necessary to prepare a concrete and improved methodology for integrating evaluation of emissions to identify the health effects actually exposed to receptors of living things. This study established the definition of cumulative risk assessment through overseas advanced cases and domestic and foreign literature reviews, and proposed a methodology for utilizing cumulative risk assessment considering health effects on multiple substances when developing industrial complexes. Applied by the proposed methodology, integrated indicators forfourtypes of hazardous heavy metals (Ni, Cr⁶⁺, Cd, As) emitted from industrial complexes were calculated, and applicability was tested with case of the industrial complex development projects conducted over the last decade (2011-2020).

• Journal of Radiation Protection and Research
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• v.47 no.1
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• pp.22-29
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• 2022

Background: A comprehensive, traceable, and easy-to-understand radiation risk indicator is desired for radiological protection. The early-onset hypothesis could be used for this purpose. Materials and Methods: An indicator for early death (IED) was developed and calculated using the epidemiological dataset from the 14^th Report of the Life Span Study (LSS) of Hiroshima and Nagasaki. By clarifying the calculation process, IED for all-cause mortality was estimated. In addition, the characteristics of IED for solid cancer mortality and cardiovascular mortality as well as those of men and women, and their dependence on age at exposure were investigated for detailed analysis. Results and Discussion: The IED for all-cause mortality was estimated to be approximately 4 years for an acute radiation exposure of 1 Gy regardless of the fitting dose range. The cumulative death rate for all solid cancers also indicated the early-death tendency (approximately 7-10 years at 1 Gy). Although, there is a slight difference in the characteristics of the risk obtained from the LSS study and this study, it is considered that the IED in a unit of years can also be used to show the overall picture of risk due to radiation exposure. Conclusion: We developed and calculated the indicator for early death, IED, for the cumulative mortality rate of all causes of death, all solid cancers, and circulatory diseases. The quantitative values of IED were estimated to be 4 years for all causes of death, 7-10 years for all solid cancers. IED has an advantage for intuitively understanding the meaning of radiation risk since it can be obtained by a simple and traceable method.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7407-7411
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• 2014

The incidence of urban female breast cancer has been continuously increasing over the past decade with unknown etiology. One hypothesis for this increase is carcinogen exposure from tobacco. Therefore, the objective of this study was to investigate the risk of urban female breast cancer from tobacco smoke exposure. The matched case control study was conducted among Thai females, aged 17-76 years and living in Bangkok or its surrounding areas. A total of 444 pairs of cases and controls were recruited from the Thai National Cancer Institute. Cases were newly diagnosed and histologically confirmed as breast cancer while controls were selected from healthy women who visited a patient, matched by age ${\pm}5$ years. After obtaining informed consent, tobacco smoke exposure data and information on other potential risk factors were collected by interview. The analysis was performed by conditional logistic regression, and presented with odds ratio (ORs) and 95% confidence intervals(CI). From all subjects, 3.8% of cases and 3.4% of controls were active smokers while 11.0% of cases and 6.1% of controls were passive smokers. The highest to lowest sources of passive tobacco smoke were from spouses (40.8%), the workplace (36.8%) and public areas (26.3%), respectively. After adjusting for other potential risk factors or confounders, females with frequent low-dose passive smoke exposure (${\leq}7$ hours per week) from a spouse or workplace had adjusted odds ratio 3.77 (95%CI=1.11-12.82) and 4.02 (95%CI=1.04-15.50) higher risk of breast cancer compared with non-smokers, respectively. However, this study did not find any association of breast cancer risk in high dose passive tobacco smoke exposure, or a dose response relationship in cumulative passive tobacco smoke exposure per week, or in the active smoker group. In conclusion, passive smoke exposure may be one important risk factor of urban female breast cancer, particularly, from a spouse or workplace. This risk factor highlights the importance of avoiding tobacco smoke exposure as a key measure for breast cancer prevention and control.