• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.3
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• pp.338-345
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• 2015

Objectives: The objective of this study was to evaluate the distribution of urine cadmium levels of residents in the surrounding areas of an industrial complex. Methods: During the period of three month from August to October 2012, informed consent was obtained from a total of 362 residents in Kwangyang and Yeosu. We collected urine sample from all subjects and their demographic characteristics, including alcohol drinks and smoking habits, using a questionnaire. The urine samples were analyzed using atomic absorption spectrometer. Results: The urinary cadmium geometric mean concentration of total participants was $0.87{\mu}g/g\;cr$. The results of this study showed that higher urine cadmium levels were observed in females and some subjects with a higher level of education level and a lower BMI. Also, those subjects who preferred to take vegetables and took fish 3 days before urine sampling procedure revealed higher urine cadmium concentrations. The urine cadmium concentrations of subjects in the exposed area($0.91{\mu}g/g\;cr$) were significantly higher than those in the control area($0.78{\mu}g/g\;cr$). Conclusions: An additional study is needed to assess health risks of residents in the vicinity of environment-unfriendly areas, coupled with endeavors to examine possible heavy metals contamination factors that may affect the human body.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.3
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• pp.294-300
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• 2015

Objectives: The aim of this study is to identify physicochemical properties such as chemical composition, size, shape and crystal structure of powder byproducts generated from a metallization process and its 1st scrubber in the semiconductor industry. Methods: Powder samples were collected from inner chambers during maintenance of the W-plug process equipment (using tungsten hexafluoride as a precursor material) and its 1st scrubber. The chemical composition, size and shape of the powder particles were determined by field emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM) equipped with an energy dispersive spectroscope (EDS). The crystal structure of the powders was analyzed by X-ray diffraction (XRD). Results: From the SEM-EDS and TEM-EDS analyses, O and W were mainly detected, which indicates the powder byproducts are tungsten trioxide ($WO_3$), whereas Al, F and Ti were detected as low peaks. The powder particles were spherical and nearly spherical, and the particle size collected from the process equipment and its 1st scrubber showed 10-20 nm (agglomerates: 55-90 nm) and 16-20 nm (agglomerates: 80-120 nm) as primary particles, respectively. The XRD patterns of the yellow powder byproducts exhibit five peaks at $23.8^{\circ}$ $33.9^{\circ}$ $41.74^{\circ}$ $48.86^{\circ}$ and $54.78^{\circ}$ which correspond to the (200), (220), (222), (400), and (420) planes of cubic $WO_3$. Conclusions: We elucidated the physicochemical characteristics of the powder byproducts collected from W-plug process equipment and its 1st scrubber. This study should provide useful information for the development of alternative strategies to improve the working environment and workers' health.

• Journal of Environmental Health Sciences
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• v.41 no.6
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• pp.412-424
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• 2015

Objectives: An ultra dry air environment of nearly ${\leq}2%$ RH is often required in lithium battery factories. The objective of this study is to evaluate the subjective eye, pulmonary, nose, and skin symptoms of workers exposed to ultra-low relative humidity and thionyl chloride. Methods: We recruited 274 workers using a self-reported questionnaire in March 2014. Those who worked in ultra-low relative humidity and with thionyl chloride were identified and their prevalence of symptoms was compared with that of other workers. We excluded white collar workers, researchers and other workers who were exposed to various hazard factors, and finally included 164 workers. Results: There were significant differences in the rate of self-reported eye and skin symptoms between exposure group_1 and exposure group_2. Exposure group_2 experienced more frequent eye, and skin symptoms. Multinomial logistic regression analysis for experience of dry eye symptoms and skin symptoms in exposure group_2 showed that dry eye symptoms (odds ratio [OR], 6.33, 95% confidence interval [CI], 2.19-18.24, p<0.001), and itchiness (OR, 6.45, 95% CI, 1.94-21.43, p<0.01) were the significant variables. The complaints of workers experiencing ultra-low relative humidity and thionyl chloride were high compared with other workers. Conclusion: These findings suggest that exposure to ultra-low relative humidity and thionyl chloride may be associated with more frequent eye and skin symptoms than exposure to ultra-low relative humidity alone. The current precautions to protect workers from the adverse effects of ultra-low relative humidity and thionyl chloride appear to be insufficient, indicating that additional management plans to reduce symptoms should be considered.

• Physical Therapy Korea
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• v.18 no.3
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• pp.94-102
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• 2011

The purpose of this study was to review existing assessment tools for patients with low back pain and improve them through combination. A total of 314 patients with low back pain participated. Their condition was assessed using the Oswestry Disability Questionnaire (ODQ), the Quebec Back Pain Disability Scale (QBPD), and the Back Pain Functional Scale (BPFS). Rasch analysis was applied to identify inappropriate items, item difficulties, and the separation index. In this study, the 'sex life' item of the ODQ (10 items) and the 'sleeping' item of the BPFS (12 items) showed misfit statistics, whereas all items of the QBPD (20 items) were appropriate. After combining the ODQ, QBPD and BPFS, Rasch analysis was applied. The 'pain intensity', and the 'sex life' item of the ODQ and the 'throw a ball' item of QBPD showed misfit statistics. These 3 items were retained for further analysis. The remaining 42 combined ODQ-QBPD-BPFS items were arranged according to difficulty. For all subjects, the most difficult item was 'pain intensity', whereas the easiest was 'take food out of the refrigerator'. As the separation index of 42 combined ODQ-QBPD-BPFS was higher than that of the three questionnaires separately, difficulty of items varied with some need for rearrangement. The results of this study confirmed the possibility and need for a new back pain disability assessment tool, and produced one. Further study is needed to refine the questionnaire in consideration of psychosocial and occupational factors.

• Journal of Environmental Health Sciences
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• v.34 no.5
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• pp.369-373
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• 2008

The indoor environment is an important source of exposure to various aeroallergens and pathogenic microorganism. It has been shown that exposure to aeroallergens enhances the risk of indoor inhabitants developing asthma. Since the skin prick test, a typical clinical method for identification of subjects positive to allergens, can rarely cause fatal or non-fatal reactions in susceptible persons, an in vitro assay such as ELISA using serum has been considered for testing positivity against various allergens. We evaluated the validity of a serum ELISA kit for screening positive subjects to major aeroallergens including Dermatophagoides farinae, Dermatophagoides pteronyssinus, cockroach, Alternaria, Cladosporium, Aspergillus, Penicillium, dog hair, cat fur, mugwort, and ragweed. The ELISA results were compared with the skin prick test results, and sensitivity, specificity, and overall accuracy were calculated to each allergen. Higher sensitivities were obtained from D. farinae, (77.8%) and D. pteronyssinus (69.2%), but sensitivities to Aspergillus, Penicillium, dog hair, cat fur, and ragweed were very low down to 0%. Specificity ranged from 88.7% (cat fur) to 100% (mugwort and ragweed). Overall the accuracy of the serum ELISA kit was relatively high, in that the lowest was 85.1% for cat fur and the highest was 98.6% for Alternaria, Cladosporium, and ragweed. Considering specificity and overall accuracy for the serum ELISA kit, it may be considered reliable. However, when the kit is used for screening purpose, positivity to aeroallergens should be carefully determined since sensitivity for the kit is low.

• Journal of Environmental Health Sciences
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• v.34 no.5
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• pp.395-402
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• 2008

Road traffic noise causes considerable disturbance and annoyance in exposed inhabitants. Particularly, arterial road noise is a significant environmental problem in many urban areas in which higher traffic volume and higher car speed occur. Arterial road noise became the target of this investigation in Seoul, South Korea. Noise levels were measured at four points that were based on distance from roadside at the same measurement site and under the conditions as reported by the National Institute of Environmental Research (NIER) in 1999. The average noise levels ($L_{eq,1h}$) of the arterial road was 80.3 dBA at 5 m, 77.4 dBA at 10 m, 73.7 dBA at 20 m, 70.9 dBA at 30 m. A comparison between 1999 and 2008's measurement values has shown that in 2008 noise level is up by about 1.5 dBA, traffic volume has increased by about 15.7%, while car speed has decrease by about 8%. The relationship between 2008' measured values and predicted values using the NIER Equation is low under 10 m from the roadside. The influence range of arterial noise is calculated at 26 m for road noise limits in daytime. In relation to the comparison between traffic volume and noise level, the equivalence in traffic volume (Light car+10xHeavy car) is higher than other variables.

• Journal of Environmental Health Sciences
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• v.46 no.1
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• pp.96-102
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• 2020

Objectives: This study identified factors impacting radiation knowledge among aircrew, who are affected by cosmic radiation exposure due to their occupational environment. Methods: In September 2019 we conducted an online survey of aircrew through a Google link. We evaluated the level of radiation knowledge using a ten-item (10 points) questionnaire. The following exploratory variables were evaluated in relationship with the level of radiation knowledge using univariable linear regression models: sex, age, duration of employment, position level, company, marriage, education level, personal/family history of disease, and the number of times acquiring information on radiation through various channels (internet searching, watching television, reading newspaper, conversation about radiation with aircrew/non-aircrew, in-house training). With a p of 0.2 in univariable models, we built a multivariable linear regression model using a stepwise selection method. Results: The average radiation knowledge score of the 356 respondents was 7.22. Univariable linear regression analysis showed that radiation knowledge of the aircrew was associated with their company, position level, age, and number of conversations with other aircrew members. Our multivariable model showed that the radiation knowledge level of aircrew decreased as they had more conversations about radiation with other aircrew members and as their age increased. Conclusions: Korean air crew showed a lower level of radiation knowledge as their age and the number of conversations with colleagues increased. The study suggests that more education is needed in order for aircrew to gain accurate radiation knowledge.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.1
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• pp.11-24
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• 2011

Working in a research laboratory means exposure to a wide range of hazardous substances. Several studies indicated that laboratory workers, especially working with chemicals, might have an increased risk of certain cancers. However, exposure assessment data in laboratory settings are scarce. This study was performed to examine several approaches for quantitatively assessing the exposure levels to volatile organic compounds (VOCs) among workers in chemistry laboratories. The list of 10 target VOCs, including ethanol, acetone, 2-propanol, dichlormethane, tetrahydrofuran, benzene, toluene, n-hexane, ethyl acetate, chloroform, was determined through self-administered questionnaire for six chemistry research laboratories in a university, a government-funded research institute, or private labs. From September to December 2008, 84 air samples were collected (15 area samples, 27 personal time weighted samples, 42 personal task-basis short-term samples). Real time monitors with photo ionization detector were placed during the sampling periods. In this study, benzene was observed exceeding the action levels, although all the results were below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV). From the air sampling results, we concluded that (1) chemicals emitted during experiments could directly affect to neighbor office areas (2) chemical exposures in research laboratories showed a wide range of concentrations depending on research activities (3) area samples tended to underestimate the exposures relative to personal samples. Still, further investigation, is necessary for developing exposure assessment strategies specific to laboratories with unique exposure profiles.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.2
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• pp.88-93
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• 2010

To confirm and quantify asbestos fibers released from the asbestos-cement slate roofs due to weathering, three houses, selected based on the year of built - 60's, 70, and 80's, were investigated. All of them were located in the downtown of Seoul. Rain or snow-melt water was collected from the roof in a 3.5 liter plastic bottle. A known amount of collected water was filtered on the 37 mm membrane filter, ashed in a muffle furnace, and subsequently treated with HCl to remove organic material. The treated remaining was refiltered on a 25mm membrane filter for PLM and PCM analyses. The NIOSH 7400 method was utilized for PCM counting. In addition, SEM/EDX was used to confirm the asbestos types. The results of this study showed that chrysotile fibers were confirmed by PLM in all samples analyzed. A significant amount of asbestos fibers were found in the water samples. The ranges of asbestos fibers counted from the samples collected in the 60's, 70's, and 80's were; 10,406.3~55,575.6 f/L, 5,218.8~38,126.2 f/L, and 2,906.3~7,798.6 f/L, respectively. As anticipated, concentrations of asbestos fibers increased with time of installment of the roofing material. We conclude that weathering can be a significant factor on the release of asbestos fibers from the asbestos cement products. Since asbestos fibers released into environment can be a source of significant health hazard, countermeasures, such as replacement, removal, and encapsulation of weathered asbestos slate, should be initiated immediately.

• Molecular & Cellular Toxicology
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• v.4 no.1
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• pp.61-65
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• 2008

Although dietary intake of pregnant is supposed to have beneficial effects on development of infants, it may be harmful for fetal growth and development since specific food is a common source of toxicants including heavy metal. The purpose of this study was to investigate the association of maternal food intake and mid-pregnancy and their newborns blood lead levels. Pregnant women of 18-20 weeks of gestation were recruited from prenatal clinic in Seoul, Cheonan and Ulsan. In 422 pregnant women, dietary intake during pregnancy was assessed by a 24-hour recall method. Blood sample from pregnant (18-20 wks) and their cord blood at delivery were collected. Blood leas levels were analyzed by atomic-absorption spectrometry methods. Pregnant blood lead levels whose meat and meat products intake were in the highest quartile was significantly higher compared to the lowest quartile. Maternal meat and meat products intake was positively correlated maternal blood lead level (r=0.120, P=0.014). After adjusting for age, maternal blood lead level was positively correlated with their newborn blood lead level (r=0.303, P=0.030). As maternal food intake effects on blood lead levels of pregnant, careful regulation of food intake during pregnancy is perceives to be important in order to bring about desirable pregnancy outcomes.