• 한국산업보건학회지
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• 제33권1호
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• pp.3-5
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• 2023

Objective: This study introduces exposure concentrations of time-weighted average standard (TWA) evaluation and short-time exposure standard (STEL) evaluation for trichloroethylene in the cleaning process. Methods: Trichloroethylene measurement was conducted according to the KOSHA Guide (A-24-2019) method. It was carried out twice. Results: As a result of the first measurement, TWA concentration exceeded 4 times the exposure standard and STEL concentration exceeded 16 times, but the inaccuracy and breakthrough of the collection time could not be considered, so the second measurement was conducted. The second measurement result was lower than the first measurement result, but exceeded the exposure standards (TWA, STEL). Conclusions: We were able to confirm that the exposure level of workers in the cleaning process using trichloroethylene exceeded the exposure standard. And it is also considered necessary to grasp the approximate concentration using a detector tube in the preliminary survey.

• 한국치위생학회지
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• 제10권4호
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• pp.717-725
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• 2010

Objectives : This study was to determine the level of occupational exposure and quality of life and to investigate the effect of variables related occupational exposure on quality of life in dental hygienists. Methods : A survey questionnaire was mailed to dental hygienists from April 4 to May 15, 2010. The subjects were 256(56.9%), who were worked in dental hospital and clinic with mean age of $29.59{\pm}7.30$. Quality of life was measured using the WHOQOL-BREF. It consists of 26 items, each with 5-point likert scale. Self control of occupational exposure was measured using the 3-items. The data were analyzed with chi-square, t-test, one-way ANOVA, pearson correlation coefficients and multiple regression using the SPSS WIN 17.0 program. Results : Regarding quality of life, the subjects was a mean of 90.73 out of a maximum 130 points. The level of self control occupational exposure a mean of 3.20 out of a maximum 5 points. Self control of occupational exposure, frequency of panorama radiography, work experience of radiography had a significant impact on quality of life in dental hygienists. Conclusions : Based on the findings, occupational exposure is negatively associated with quality of life in dental hygienists. These results suggest that health promotion program should be considered various factors related occupational exposure in dental hygienists.

• 한국환경보건학회지
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• 제37권5호
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• pp.358-368
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• 2011

Objectives: In order to evaluate the association between occupational exposure to chloroethylene (TCE) and risk of non-Hodgkin lymphoma (NHL), we conducted a meta-analysis of retrospective cohort studies and casecontrol studies and attempted to summarize the evidence of the association from molecular-epidemiological studies and experiments with human cells. Methods: In the meta-analysis, we restricted the analysis to those studies with data for chlorinated solvents, degreasers, or TCE. Studies involving dry cleaners or launderers were excluded from the analysis because use of TCE as a dry cleaning fluid has been rare since the 1960s. The data were combined using a random-effects model to estimate the summary risks (OR and RR) and 95% confidence intervals (CIs). Molecular evidence of the effect of TCE on human immune system were also reviewed and summarized. Results: Occupational exposure to TCE was strongly associated with NHL among cohort studies (number of studies=13, summary RR=1.33, 95% CI=1.04-1.70) whereas the association was not statistically significant among case-control studies (number of studies=15, summary OR=1.10, 0.98-1.23). When exposure level was considered, it became statistically significant for the highest exposure level (number of studies=5, summary OR=1.70, 1.25-2.32). Molecular evidences showed that TCE exposure in human or cultured human cells may cause a significant decrease immune cell subsets and changes in hormone levels related to immune response. Conclusions: Our results from meta-analysis and additional molecular evidence suggest that occupational exposure to TCE may cause NHL. However, unmeasured potential confounding and unclear dose-response relationships warrant further study on the role of TCE exposure in NHL carcinogenesis.

• Archives of Pharmacal Research
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• 제29권12호
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• pp.1158-1163
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• 2006

More than 95% of lead, a environmental heavy metal, entering into blood accumulates in erythrocytes suggesting erythrocytes as an important target of lead toxicity. Recent studies reported that erythrocytes could contribute to blood coagulation via phosphatidylserine (PS) exposure in erythrocytes. However, in vivo effects of chronic lead exposure especially by drink-ing water on procoagulant activity of erythrocytes have not been studied yet. In the present study, we investigated the effects of chronic exposure of lead by drinking water on erythrocytes in rats. Groups of 40 male rats were provided with drinking water containing various concentrations of lead for 4 weeks and complete blood cell count, procoagulant activities of erythrocytes and platelets were evaluated with basic inspections on body weight and food/water consumption. The administration of lead containing drinking water increased the blood lead level (BLL) in a dose-dependent manner up to $22.39{\pm}2.26\;{\mu}g/dL$. Water consumption was significantly decreased while food consumption or body weight gain was not affected. In contrast to the previous findings with acute lead exposure, chronic lead exposure failed to increase PS exposure in erythrocytes with statistical significance although some trends of enhancement were observed. It implies that a certain adaptation might have happened in body during repeated exposure to lead, resulting in attenuation of PS exposure. With this study, we believe that a valuable information was provided for the study on the toxicological significance and the risk assessment of lead contaminated drinking water.

• 한국분무공학회지
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• 제23권2호
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• pp.81-89
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• 2018

The objective of this study is to estimate the level of exposure of traffic-related air pollutants (TRAPs) on the pedestrians in Seoul area. The road network's link-based pollutant emission was calculated by using a set of mobile source emission factor package and associated activity information. The population information, which is the number of pedestrian, was analyzed in conjunction with the link-based traffic emissions in order to quantify exposure level by selected 23 spots. We proposed the Exposure Intensity, which is defined by the amount of traffic emission and the population, to quantify the probability of exposure of pedestrian. Link-based traffic NOx and PM emissions vary by up to four times depending on the location of each spot. The Hot-spots is estimated to be around 1.8 times higher Exposure Intensity than the average of the 23 selected spots. The information of Exposure Intensity of each spot allows us to develop localized policies for air quality and health. Even in the same area, the Exposure Intensity over time also shows a large fluctuation, which gives suggestions for establishing site-specific counter-measures.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.808-813
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• 2011

There are hundreds of thousands call center workers wearing acoustic device. However, researches and noise exposure measurements on the noise transmitted from acoustic devices have seldom been performed due to the difficulty of measurement and to the absence of the measuring method in Korea. The aim of this study is to set up management measures to protect hearing loss on the call operator by acquiring measurement data of noise transmitted from the headset Noise exposure measurements of 17 operators were performed in 7 call centers and Head and Torso Simulator method in compliance with the ISO Standard 11904-2 was used for the measurement of noise transmitted from the headset Sound pressure levels(SPL) transmitted from the headset were 73.2~86 dB(A). The operator exposed to the highest SPL set up his volume control at 9 which was the highest volume level. The volume control level, adjustable from 1 to 9, could be identified 12 out of 17 operators and the range of volume levels was 4.5~9. As a result of Pearson Correlation Analysis, the correlation between volume level and SPL transmitted from the headset showed high relation as significance at the 0.672 level(p<0.05). To protect hearing loss of call center operators, it is more practical and effective measure to limit the volume level below the noise exposure level, i.e. 85 dB(A), rather than to carry out noise monitoring considering cost-effective aspect.

• 한국소음진동공학회논문집
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• 제21권7호
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• pp.615-621
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• 2011

There are hundreds of thousands call center workers wearing acoustic device. However, researches and noise exposure measurements on the noise transmitted from acoustic devices have seldom been performed due to the difficulty of measurement and to the absence of the measuring method in Korea. The aim of this study is to set up management measures to protect hearing loss on the call operator by acquiring measurement data of noise transmitted from the headset. Noise exposure measurements of 17 operators were performed in 7 call centers and head and Torso simulator method in compliance with the ISO standard 11904-2 was used for the measurement of noise transmitted from the headset. Sound pressure levels(SPL) transmitted from the headset were 73.2~86 dB(A). The operator exposed to the highest SPL set up his volume control at 9 which was the highest volume level. The volume control level, adjustable from 1 to 9, could be identified 12 out of 17 operators and the range of volume levels was 4.5~9. As a result of pearson correlation analysis, the correlation between volume level and SPL transmitted from the headset showed high relation as significance at the 0.672 level(p<0.05). To protect hearing loss of call center operators, it is more practical and effective measure to limit the volume level below the noise exposure level, i.e. 85 dB(A), rather than to carry out noise monitoring considering cost-effective aspect.

• 대한의생명과학회지
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• 제22권4호
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• pp.140-149
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• 2016

All pesticides must be assessed strictly whether safe or not when agricultural operators are exposed to the pesticides in farmland. A pesticide is commonly regarded as safe when estimated dermal absorption amount is lower than the acceptable operator's exposure level (AOEL). In this study, dermal absorption rate of chlorpyrifos, a widely used organophosphate insecticide, was investigated using rat dermal tissue model. Chlorpyrifos wettable powder solved in water (250, 500 and 2,500 ppm) was applied to freshly excised rat dermal slices ($341{\sim}413{\mu}m$ thickness) on static Franz diffusion cells at $32^{\circ}C$ for 6 hours. After exposure period of 6 hours, and then washing-at residual amount of chlorpyrifos was analyzed in dermal tissues, tape strips, washing solution, washing swabs of receptor bottles and receptor fluids at 1, 2, 4, 8 and 24 hours. Chlorpyrifos was only detected in dermal tissue but not found in receptor fluid at each concentration and time point, and the absorption rate of 250, 500 and 2,500 ppm was 2.36%, 1.96% and 1.69%, respectively. The estimated exposure level of chlorpyrifos was calculated as 0.012 mg/kg bw/day. The health risk for farmers in this condition is a level of concern because the estimated exposure level is 12 times higher than AOEL 0.001 mg/kg bw/day. However, actual health risk will be alleviated than estimated because absorbed chlorpyrifos is not permeated into internal body system and only retained in skin layer.

• 한국산업보건학회지
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• 제3권1호
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• pp.100-109
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• 1993

This study was performed to evaluate the asbestos exposure levels and variations in textile, brake lining manufacturing and slate manufacturing industries. For this study, fifteen plants of brake lining manufacturing industry, 7 plants of textile industry, and 2 plants of slate manufacturing industry were selected and surveyed. Geometric means (GMs) of airborne asbestos concentrations in textile, brake lining manufacturing, and slate manufacturing industries were 1.42 f/cc(0.07-6.1O f/cc), 0.19 f/cc(<0.01-2.67 f/cc) and 0.08 f/cc(0.02-0.67 f/cc), respectively. In textile industry overall GMs of airborne asbestos concentrations in plants with less than 50 workers and in plants with more than 50 workers were 1.60 f/cc and 0.3 f/cc, respectively. Therefore, the size of plant showed some difference in the airborne asbestos concentrations. Three out of 7(42.9%) exceed the Korean standard, 2 f/cc, and every plant exceed the USA standard, 0.2 f/cc of the OSHA-Permissible Exposure Level(OSHA-PEL). Especially, one plant showed the highest average concentration of 2.87 f/cc. In brake lining manufacturing industry, the plants with less than 50 workers showed 0.22 f/cc. The plants with more than 50 workers showed 0.18 f/cc. All plants showed the exposure level below the Korean standard. Five of 15 (33.3%) were above the OSHA-PEL. One plant showed the highest average concentraton of 0.84 f/cc. In slate manufacturing industry, the average exposure level was 0.08 f/cc, and all of the plants were below the Korean standard and the OSHA-PEL.

• 한국산업보건학회지
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• 제7권2호
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• pp.264-278
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• 1997

The average level of coke oven emissions in the work site was $0.04mg/m^3$, which was below the permissible exposure level($0.2mg/m^3$). The average level of 1-OH-pyrene in the urine of the wokers was $0.745{\mu}mol/mol$ creatinine which is far below the BEI($2.3{\mu}mol/mol$ creatinine). Correlation between airborne COE in working environment and urinary 1-OH-pyrene concentration was statistically significant. These results explain that exposure level by biological monitoring is much higher than that by environmental monitoring. The effect of hygienic measures for reducing internal exposure to polycyclic aromatic hydrocarbons was studied in 25 coke-oven workers. Their 1-OH-pyrene levels increased by $0.77{\mu}mol/mol$ creatinine, while working with ordinary protective measures. The average levels of the same workers with extra hygienic measures increased by $0.34{\mu}mol/mol$ creatinine. The average increase of the urinary 1-OH-pyrene concentration over the 5-day work week was 56.3%($0.43{\mu}mol/mol$ creatinine) lower when extra hygienic measures were taken(p=0.0001).