• Environmental Analysis Health and Toxicology
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• 제27권
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• pp.5.1-5.10
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• 2012

Objectives: The purpose of this study was to assess the risk of ingestion exposure of lead by particle sizes of crumb rubber in artificial turf filling material with consideration of bioavailability. Methods: This study estimated the ingestion exposure by particle sizes (more than 250 um or less than 250 um) focusing on recyclable ethylene propylene diene monomer crumb rubber being used as artificial turf filling. Analysis on crumb rubber was conducted using body ingestion exposure estimate method in which total content test method, acid extraction method and digestion extraction method are reflected. Bioavailability which is a calibrating factor was reflected in ingestion exposure estimate method and applied in exposure assessment and risk assessment. Two methods using acid extraction and digestion extraction concentration were compared and evaluated. Results: As a result of the ingestion exposure of crumb rubber material, the average lead exposure amount to the digestion extraction result among crumb rubber was calculated to be $1.56{\times}10^{-4}$ mg/kg-day for low grade elementary school students and $4.87{\times}10^{-5}$ mg/kg-day for middle and high school students in 250 um or less particle size, and that to the acid extraction result was higher than the digestion extraction result. Results of digestion extraction and acid extraction showed that the hazard quotient was estimated by about over 2 times more in particle size of lower than 250 um than in higher than 250 um. There was a case of an elementary school student in which the hazard quotient exceeded 0.1. Conclusions: Results of this study confirm that the exposure of lead ingestion and risk level increases as the particle size of crumb rubber gets smaller.

• Health Policy and Management
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• 제30권4호
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• pp.505-512
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• 2020

Background: In monitoring exposure to environmental smoke (ETS), biomarkers can overcome the subjectivity and inaccuracy of self-reporting measurements, and have the advantage of reflecting ETS exposure in all places. This study aims to evaluate the effectiveness of ETS exposure measurement using biomarkers such as urine cotinine. Methods: This study used the Korea National Health and Nutrition Survey data from 2009 to 2018. A total of 28,574 non-smokers with urine cotinine data were selected for the study. The cotinine concentration and ETS exposure rate using urine cotinine was estimated and then compared with the self-reporting measurements. The degree of agreement among measurements of ETS exposure was confirmed. Results: As a result of measuring ETS exposure with urine cotinine, 23,594 (83.8%) out of 28,574 subjects were classified as to exposure groups. This estimate differs significantly from measurements made by self-reporting. In addition, the average concentration of cotinine in non-smokers has decreased to a 10th level over the past 10 years. Based on the biomarker, the sensitivity of the self-reporting was 8.5%-29.0%, the specificity was 16.4%-19.5%, and the kappa value was 2.0%-5.8%. Conclusion: The findings of our study show that self-reporting measurement does not well reflect the extent to which non-smoker's exposure to smoking materials. Whereas cotinine concentration has decreased significantly over the past 10 years, the ETS exposure rate has not reduced. It strongly suggests the need for intervention in the group of non-smokers exposed to low concentrations of smoke. Therefore, an assessment using biomarkers such as cotinine-based measurement should be made in the Health Plan 2030.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• 제15권2호
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• pp.144-152
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• 2005

To evaluate the effect of lead biomarkers including bone lead on neurobehavioral test in lead workers, 652 lead workers without any occupational exposure to organic solvent, mercury and arsenic were agreed to participate this study. For the control subjects 102 non-occupationally lead exposed blue collar workers in general manufacturing industries were also joined this study. All study subjects joined this study with written informed consent. The study variables of lead exposure were blood and patella lead. For the general characteristics of study subjects, standardized questionnaire regarding age, sex, past disease history, job duration, body mass index (BMI), drinking and smoking habit were provided. For the past history of neurotoxicity related diseases, all study subjects were interviewed by qualified occupational health physician. The results obtained were as follows: 1. Compared with controls without occupational lead exposure, lead exposed subjects had worse performance on all tests(p<0.05). 2. After adjustment for covariates (age, sex, job duration, education level, BMI, smoking and drinking status), the signs of the regression coefficients for blood lead were negative for 13 of the 14 tests. Blood lead was a significant predictor of poorer scores on 8 tests (simple reaction time(ms & root MSD), Trail-Making Test B, Digit Symbol Substitution, Purdue Pegboard assembly, Digit Span Test, Benton Visual Retention, and Purdue pegboard both hand). 3. After adjustment for covariates (age, sex, job duration, education level, BMI, smoking and drinking status), the signs of the regression coefficients for patella lead were negative for 12 of the 14 tests. Patella lead was a significant predictor of poorer scores on 8 tests (simple reaction time(ms). Purdue Pegboard assembly, Digit Span Test, Benton Visual Retention. Pursuit Aiming rest (no. of correct & no. of incorrect), Purdue pegboard non-dominant hand and both hand). With above results, blood lead and patella lead were associated with poorer performance of neurobehavioral tests. In addition, patella lead was confirmed to be better predictor of manual dexterity test in neurobehavioral test battery in lead workers

• Journal of the Korean Society of Radiology
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• 제15권2호
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• pp.139-145
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• 2021

This study is to confirm the range of tube voltage for Chest X-ray in DR system by comparing with dose area product (DAP) and effective dose in efficient detector exposure index (DEI) range. GE definium 8000 was used to for the phantom study. The range of tube voltage is 60~130 kVp and of mAs is 2.5~40 mAs. The acquired images were classified into efficient DEI groups, then calculated effective dose with DAP by using a PC-Based Monte Carlo Program 2.0. The signal to noise ratio (SNR) was measured at 4 regions, including the thoracic spine, the lung area with the ribs, the lung area without the ribs, and the liver by using Picture Archiving and Communication System. The significance of the group for each tube voltage was verified by performing the kruskal-wallis test and the mann-whitney test as a post-test. When set to 4 groups dependned on the tube voltage, DAP showed significant differences; 60 kVp and 80 kVp, and 60 kVp and 90 kVp (p= 0.034, 0.021). Effective dose exhibited no statistically significant differences from the all of the group (p>0.05). SNR exhibited statistically significant differences from the all of the group in the liver except compared to 80 kVp and 90 kVp (p<0.05). Therefore, high tube voltages of 100 kVp or more need to be reconsidered in terms of patient dose and imaging in order to represent an appropriate chest X-ray image in a digital system.

• Molecular & Cellular Toxicology
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• 제3권3호
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• pp.185-189
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• 2007

Gene expression levels of choriogenin, vitellogenin and estrogen receptor were determined using Reverse transcription (RT)-PCR technique after exposure to estrogenic chemical bisphenol A in the Korean wild medaka (Oryzias sinensis). These genes have been known to be induced in male test fish when the fish are exposed to estrogenic chemicals. Therefore they can be suggested as a possible biomarker of endocrine disruption in fish, however, relatively little has been known about these genes expression by estrogenic chemicals in Korean wild fish. Mature male Oryzias sinensis were treated with bisphenol A at nominal concentrations of 0.02, 0.2 and 2 mg/L for 6 days and total RNA was extracted from the livers of treated fish for RT-PCR. When the five biomarker genes were amplified by RT-PCR in the same condition, mRNA induction level of each gene was elevated with different sensitivities. Conclusively, the results of this work indicated that measurement of vitellogenin and choriogenin using RT-PCR is effective as a simple tool for the screening of estrogenic chemicals and suggested that O. sinensis would be a suitable model fish for the environmental risk assessment of potential endocrine disruptors.

• Journal of Physiology & Pathology in Korean Medicine
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• 제28권1호
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• pp.94-101
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• 2014

We studied to investigate the erythema reduction effects generated by Gagam-Jawoonaek(GJ) application(appl.) after UV exposure. Twenty women in their twenties to fifties with no skin diseases were recruited. We exposed UV as a 6 subsites on the left upper arm of subjects using multi-port solar simulator. After setting Gagam-Jawoonaek(GJ) application(appl.) subsites and non-appl. subsites, we measured erythema degrees($a^*$ values) of the subsites using spectrophotometer. We measured $a^*$ values four times(before UV exposure, before application of GJ, twenty-four and forty-eight hours after first application of GJ). We analyzed data using student's t-test. After UV exposure, $a^*$ values on the left upper arm increased. Twenty-four hours after first GJ treat., the changes of $a^*$ value on GJ treat. subsites($1.22{\pm}0.13AU$) were bigger than GJ non-treat. subsites($1.04{\pm}0.12AU$), but there was no statistically significance. Forty-eight hours after first GJ treat., the changes of $a^*$ value on GJ treat. subsites($1.95{\pm}0.11AU$) were bigger than GJ non-treat. subsites($1.58{\pm}0.13AU$), a statistically significance. Gagam-Jawoonaek could decrease erythema by UV exposure.

• Journal of Korean Academy of Fundamentals of Nursing
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• 제25권4호
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• pp.293-300
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• 2018

Purpose: This study was done to identify the relationship between nurses' compliance with safety guidelines for the use of antineoplastic agents, observable symptoms, and stress from occupational exposure. Methods: The participants were 172 nurses from six general hospitals in a metropolitan area. They had administered antineoplastic agents at least three months prior to the study. Data were collected using self-report questionnaires, and then analyzed using SPSS/WIN 23.0 for descriptive statistics, t-test, one-way ANOVA, $Scheff\acute{e}$ method, and Pearson correlation coefficient. Results: The average score on the guideline for safety compliance was 87.75 points out of a total of 100. The average score for observable symptoms of exposure to antineoplastic agents was 30.12 (28~56) points, and that for mean stress was 33.52 (15~60) points. Observable symptoms and stress from occupational exposure showed a statistically significant positive correlation (r=0.34, p<.001). Conclusion: To increase the degree of compliance with safety guidelines for antineoplastic agents, hospitals should lower the chance of exposure to antineoplastic agents, as well as minimize the observable symptoms and stress from occupational exposure. Periodic education and policy support are needed to improve compliance with safety guidelines for antineoplastic agent use.

• Korean Journal of Community Nutrition
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• 제28권3호
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• pp.192-205
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• 2023

Objectives: Previous studies have evaluated the association between mercury exposure and obesity but have yielded mixed conclusions. The aim of this study was to systematically review and summarize scientific evidence regarding the association between mercury exposure and obesity in the human population. Methods: We conducted a systematic search of PubMed, Web of Science, Scopus, and Science Direct for articles related to mercury exposure and obesity. Meta-analyses of the highest and lowest categories of mercury levels were evaluated using a random effects model. Begg's test was used to detect publication bias. Results: A total of 9 articles were included. The pooled random effects odds ratio (OR) for mercury exposure and obesity of all 9 studies was 1.66 (95% confidence interval [CI]: 1.16-2.38). This positive association was evident in adults (OR: 1.61, 95% CI: 1.02-2.54) and among studies with Asian populations (OR: 2.00, 95% CI: 1.53-2.59), but not among those with North America/African populations (OR: 0.90, 95% CI: 0.50-1.65). Conclusions: The present meta-analysis identified a positive association between mercury exposure and obesity. These findings suggest that toxic environmental metals such as mercury may be an important risk factor for obesity along with dietary habits and lifestyles.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• 제25권4호
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• pp.482-492
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• 2015

Objectives: Exposure Assessment for workplace hazards where the exposure level is below occupational exposure limits(OELs) has been performed without considering either the degrees of risk or exposure levels and has failed to lead to intervention in many cases. The objective of this study was to suggest and test an application framework for risk assessment methodology under the current exposure assessment system in Korea. Materials: First, we investigated the exposure assessment systems in Korea and other countries. To adopt some risk assessment techniques, we also analyzed risk assessment systems and compared them to exposure assessment systems. A few suggestions were made. We held a public hearing during an industrial hygiene conference and took surveys using a questionnaire. Results: The first suggestion was to implement the risk assessment and exposure assessment through a "one-stop" system. In that case, one expected question would be who has been doing the jobs so far. In most cases, industrial hygiene consulting services or laboratories have been performing exposure assessment for business owners. Business owners are required to perform risk assessment. As two different groups of people will be required to implement two things in a one-stop system, they need to share information. As an information vehicle to share information, commonly filed survey checklists were suggested. The second suggestion was to categorize exposure level into four groups instead of the current binary divisions based on OELs. In the risk assessment system, exposure level is divided into four groups utilizing the cut-points of 10%, 50%, and 100% of OELs. The same schema can be adopted in the exposure assessment system and different levels of requirements can be assigned for each group. The third suggestion was regarding the regulation system. To provide the suggestions some thrust toward being implemented in the field, changes should be made in the legal system. Two different types of new exposure assessment result reporting forms were suggested. Some investigations such as an ergonomic survey are officially accepted as risk assessment under the current legal system. A few items were suggested to be included in the exposure assessment result reporting to be accepted as risk assessment. A pilot study in two small factories was performed and pointed out the strengths and weakness of our suggestions. Conclusions: Discussions and studies on the improvement of the exposure assessment system have been held for decades and no tangible changes have yet been made. We hope this result can help realize healthy lives for workers in Korea.

• Journal of Environmental Health Sciences
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• 제41권6호
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• pp.405-411
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• 2015

Objectives: The purpose of this study is to evaluate the optimum conditions for oral mucosal irritation testing using the buccal pouch of hamsters. Methods: Test materials were applied to the buccal pouch of seven-week old male Syrian hamsters (SLC, Japan) four times at one-hour intervals and macroscopic changes were examined at 24 hours after final treatment. After sacrifice, the buccal pouches were removed and prepared for histopathological evaluation. In order to set the exposure time, we performed exposure tests of 5, 12, 18 and 23 minutes using sodium lauryl sulfate (SLS) 1% and set the treatment volume from the test results at 2, 3, or 4 ml treatment using SLS 1%, Triton X-100 1% and ethanol. After setting the experimental conditions, seven groups of materials [sodium lauryl sulfate (SLS) (1%), Triton X-100 (1%), hydrogen peroxide (3%), ethanol (100%), chlorhexidine (0.2%, 2%), phosphate buffer saline (PBS)] were assessed. Results: Experimental conditions of material exposure time were fixed as 18 minutes from the exposure tests of 5, 12, 18 or 23 min using sodium lauryl sulfate (SLS) 1%. Treated volume was set as 4 ml per each pouch from the test results of 2, 3, or 4 ml treatments using SLS 1%, Triton X-100 1% and ethanol. The results in terms of irritation degree were in the order of sodium lauryl sulfate (SLS) (1%) > Triton X-100 (1%) ${\fallingdotseq}$ hydrogen peroxide (3%) > ethanol (100%) ${\fallingdotseq}$ chlorhexidine (0.2%, 2%) > phosphate buffer saline (PBS). Conclusion: From this study, suitable conditions for hamster mucosal irritation testing were suggested and this method was verified through materials commonly used on oral mucosal membranes.