• Title/Summary/Keyword: harmful materials

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A Thermal Study of the Harmful Chemical Species of Charcoal and Their Transformation during Combustion (숯의 유해물질과 이들의 연소 중 상변화에 대한 열분석 연구)

  • Yoon, Hye-On;Kim, Ki-Hyun
    • Journal of the Mineralogical Society of Korea
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    • v.24 no.2
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    • pp.101-110
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    • 2011
  • Charcoal burning in the process of manufacture and ordinary use often release many constituent chemical species. As a result of open burning, the chemical composition as well as the physical properties of original material changes through the modification of surface properties of charcoal. Surface modification could be more responsible toward the outside elements for surface adsorption, it becomes easy to adsorb more toxic elements through surface adsorption. In this study, four kinds of commercially available charcoal were studied against the chemical and thermal stability along with the heavy metals and organic hazardous substances. Thermo gravimetric analysis (TGA) and differential scanning calorimetry, from room temperature to $400^{\circ}C$, were performed to study the weight loss and the changes in the behavior of those substances. According to TGA analysis, about 10% of weight loss was happened before $200^{\circ}C$. It was found that related weight loss of this temperature region may responsible to the gas phase organic matter. Natural charcoal, K1 and C1 show 15% of loss during the reaction heated to $400^{\circ}C$, while the artificial charcoal K2, C2 show the weight loss of about 20% was found. This is consistent with the main organic matter and VOC analysis results shown. Chemical composition based on the x-ray diffraction analysis was carried out. X-ray diffraction analysis reveals the existence of chemical additive in the forms of $Ba(NO_3)_2$, $BaCO_3$, and $NaNO_3$.

Study on the methods of risk assessment of human exposure by using of PVC flooring (PVC 바닥재 인체 노출에 따른 위해성 평가 연구)

  • Kim, Woo Il;Cho, Yoon A;Kim, Min Sun;Lee, Ji Youmg;Kang, Young Yeul;Shin, Sun Kyoung;Jeong, Seong Kyoung;Yeon, Jin Mo
    • Analytical Science and Technology
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    • v.27 no.5
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    • pp.261-268
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    • 2014
  • In advanced countries, a variety of consumer exposure assessment models including CONSEXPO, are developed to manage risks of consumer products containing hazardous materials. The models are used to assess the risks of exposure to hazardous chemicals in consumer products, which serves as a foundation for regulation standards. In this study, exposure assessment models applicable for various scenarios were reviewed and a proper model was applied for the selected products and risk assessment was conducted at each stage to establish a risk assessment procedure for different types of products. Based on the exposure scenario, exposure factor was selected and according to the algorithm produced based on CONSEXPO exposure model, some level of phthalates were detected from some types of PVC flooring. However, a correlation between phthalate content and migration rate showed r-square 0.0065, little correlation, which is inadequate for estimating standard value. For this reason, it seems valid that the current standard be in place. Additionally, any new standard was not suggested as VOCs were not found harmful to human health, allowing the existing standard to be continuously applied. No migration rate was found for heavy metals and risk assessment was not performed accordingly. In this aspect, it is presumed that hazards to health through dermal exposure would be very little.

Study of Radon Management in the Environmental Impact Assessment Stage (환경영향평가 단계에서의 라돈 관리에 대한 연구)

  • Kim, Im-Soon;Oh, Hong-Sok;Lee, Kwan-Hyung;Kim, Choong-Gon
    • Journal of Environmental Impact Assessment
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    • v.27 no.3
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    • pp.241-250
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    • 2018
  • Recently, negative effects on human health such as disease caused by harmful environment have been dealt with seriously. In particular, studies on the effect of radon exposure, which is known as a primary carcinogen in lung cancer due to radioactive materials, have been actively studied. In Korea, since January 1, 2018, radon measurement is mandatory when building a new apartment, so it is necessary to measure the radon concentration and submit it to the local government and it should be posted where residents can see it. Radon has only recommended standards for multi-use facilities, but now it has decided to set recommendation standards for private homes. Therefore, it should now be possible to manage the radon in the environmental impact assessment phase as well as in the Post-environmental Impact Assessment. It should be possible to share health information such as the radon concentration and the risk of radon, and participation of health experts in the environmental impact assessment stage is required. Soil, air quality, hygiene and aerial items should be improved to take into account the effects of radon on human health during the environmental impact assessment process. If the level value of conncentration of radon shows above the recommended level, then alternative measures should be prepared and mitigation measures should be prepared as well.

Spatial and Vertical Distribution of Polycyclic Aromatic Hydrocarbons in Sediment of the Shipyard Area in Gohyeon Bay (고현만 조선소 주변해역 퇴적물내 다환방향족탄화수소의 시공간적 분포특성)

  • Park, Pan-Soo;Kim, Nam-Sook;Yim, Un-Hyuk;Shim, Won-Joon;Kim, Gi-Beum
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.12 no.2
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    • pp.68-74
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    • 2009
  • Polycyclic aromatic hydrocarbons (PAHs), one of ubiquitous organic pollutants in marine environments, are major toxic components of petroleum and are produced during the incomplete combustion of organic materials. As shipyards are located inside of natural or artificial semi-enclosed bay, even a relatively weak environmental disturbance by ship-building activity can cause severe damage to marine ecosystem in the bay. Many studies of pollution in shipyard area have been focused on the antifouling agent, like tributyltin. This study aimed to investigate the effect of ship-building activity on PAH contamination. Total PAHs concentration was higher nearby and inside shipyard area than outside, implying that shipyard could be one of major source area of PAH contamination to pose harmful effects to surrounding environments. Through PAH profile and source recognition index, the source of PAHs inputs in this area was estimated to originate from both petrogenic and pyrogenic origin. PAH levels showed a significant correlation with total butyltins, indicating that ship-building activity influenced PAH concentration and distribution. Vertical distribution of PAHs historically confirmed the correlation between shipbuilding activity and PAHs contamination.

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Effects of Chitosan on the Toxicity of Environmental Pollutants (해양바이오물질이 PCB의 독성작용에 미치는 영향)

  • Lee, Hyon-Gyo;Kim, Hae-Young;Yang, Jae-Ho
    • Journal of Marine Bioscience and Biotechnology
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    • v.2 no.2
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    • pp.102-107
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    • 2007
  • Environmental contamination becomes a great public concern as our society gets industrialized rapidly. The present study examine the role of chitosan in a effort to intervene the environmental pollutant-induced toxicity. PCB-induced neurotoxicity with respect to the PKC signaling was examined. Since the developing neuron is particularly sensitive to PCB-induced neurotoxicity, we isolated cerebellar granule cells derived from 7-day old SD rats and grew cells in culture for additional 7 days to mimic PND-14 conditions. PCB showed the alteration of PKC signaling pathway. The alteration was structure-dependent. Mono-ortho-substituted congeners at a high dose showed a significant increase of total PKC activity at [$^3H$]PDBu binding assay, indicating that mono-ortho-substituted congeners are more neuroactive than non-ortho-substituted congeners in neuronal cells. PKC isoforms were immunoblotted with respective monoclonal antibodies. PKC-beta II and -epsilon were activated with mono-ortho-substituted congeners exposure. The result suggests that the position with ortho has a higher potential of altering the signaling pathway. Alteration of PKC was blocked with treatment of high molecular weight of chitosan. The study demonstrated that the ortho position in PCBs are important in assessing the structure-activity relationship. The results suggest a potential use of marine bioactive materials as a means of nutritional intervention to prevent the harmful effects of pollutant-derived toxicity.

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The Comprehension of Composition, Diversity, Related Diseases, and Treatment of the Gut Microbiome in Companion Dogs: Friend or Foe? (반려견 장내미생물의 조성, 다양성, 관련 질환 및 치료에 대한 이해: 친구인가 적인가?)

  • Choi, Jeonghyun;Hong, Yonggeun
    • Journal of Life Science
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    • v.30 no.11
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    • pp.1021-1032
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    • 2020
  • Numbers of companion animals and people rearing them are increasing in developed countries. As a result, businesses related to companion animals are becoming more advanced and specialized. Dogs have been cohabiting with humans as companions (pets) for thousands of years and, as a result, eat carbohydrate-rich foods similar to humans and maintain lives similar to their owners. Tight bonds between dogs and their owners are formed by sharing similar lifestyles, including a dwelling and food. Owners are responsible for their pets and treat them with emotional stability. Pets depend on their owners, although the food situation can cause stress. Since pet dogs are carnivorous in nature, providing pet dogs with a nutritionally balanced diet and functional materials is important for a healthy gut microbiome. Recently, the gut microbiota has become a research focus because it is associated with protection from harmful pathogens and immune regulation while maintaining physiological homeostasis. An abnormal gut microbiota is related to pathogenic processes and various gut, metabolic, mental, and neurological diseases. Additionally, pet dogs at risk of disease affect the health of their owners. Therefore, this review discusses the composition and diversity of the gut microbiota of dogs and the relationships between the gut microbiota and diseases.

Characterization of Carbonized MDF by Scanning Electron Microscopy and X-ray diffraction (주사전자현미경 및 X선회절법에 의한 탄화 MDF의 특성)

  • Lee, Seon-Hwa;Park, Sang-Bum;Kwon, Sung-Min;Park, Jong-Young;Kim, Nam-Hun
    • Journal of the Korean Wood Science and Technology
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    • v.37 no.3
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    • pp.208-215
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    • 2009
  • As a fundamental study to develop absorbing materials on harmful volatile organic compounds (VOC) such as formaldehyde, structural and crystalline characteristics of MDF carbonized at different temperatures were examined by a scanning electron microscope and an X-ray diffraction method. Fibers in surface layer of MDFs showed more compressed morphology than those in middle layer of MDFs, but the porosity of MDFs increased with increasing the carbonized temperature. The wrinkle shape was frequently surfaces of cell walls was more severe than that at the lumina of cells. The shape of pits in the fibers of carbonized MDFs were hardly changed. The cell walls of MDFs carbonized at $400^{\circ}C$ and over showed an amorphous-like structure without cell layering. X-ray diffratograms from the MDFs carbonized at $400^{\circ}C$ showed a trace of crystalline cellulose. On the other hand, an amorphous diffraction pattern from carbons was obtained with the MDFs carbonized at $1,000^{\circ}C$.

Characterization of Secondary Exposure to Chemicals and Indoor Air Quality in Fire Station (소방서 실내공간의 화학적 유해인자 2차노출과 실내공기질 특성)

  • Kim, Soo Jin;Ham, Seunghon;Jeon, Jeong Seok;Kim, Won
    • Fire Science and Engineering
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    • v.33 no.4
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    • pp.140-151
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    • 2019
  • It is to assess the indoor air quality of the chemical hazardous materials exposed to the fire after firefighters returned to the fire scene. The research subject randomly selected four fire stations located in Seoul, Korea. Two fire stations were set up as control groups after the return of the firefighting activities at the actual fire scene, and two other fire stations were set up as control groups to measure the air quality of the room at normal levels regardless of the action. We conducted 24-hour monitoring for all fire accidents that occurred in Seoul Metropolitan using fire safety map computer system. Also, indoor air quality was measured immediately after homecoming if the experiment group was to be dispatched due to an accident of intermediate or larger scale. 11 hazardous substance items such as fine dust, formaldehyde, volatile organic compounds, PAH, VCM, acidity, asbestos, CO2, NO2, O3 were measured according to the process test method. Three of 11 types of harmful substances exceeded domestic and foreign standards, and one of them was found to be close to foreign standards. In particular, total volatile organic compounds, carbon dioxide and sulfuric acids were 2.5 times, 2.2 times and 1.1 times higher than the standard. Also, for formaldehyde and sulfuric acid, it was measured higher in the control group than in the case group. This findings could be used in policies to improve indoor air quality in the fire station of the Seoul Metropolitan Government.

Chemical Changes of the Deep Fat Frying Oils Used Commercially (일반시장에서 튀김식품에 사용된 기름의 화학적 변화)

  • Joo, Kwang-Jee;Ha, Gy-Sook
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.18 no.3
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    • pp.247-254
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    • 1989
  • In deep-fat frying, the fats and oils are used over and over again, and moisture and air are mixed in to the hot oil. Many reports related to these fats and oils have been established that thermal and oxidative decomposition products and polymers formed under the conditions of deep fat frying are harmful to health. This work was carried out with 3 domestic frying oils and 6 used oils commercially, and that there were difficulties in finding a good definition between fresh oil and used oil with adding unheated oil. As starting materials, commercially used soybean oil and rapeseed oil already passed over induction period in the lipids oxidation standard. From the qualitative point of view, they were inferior to domestic frying oils. Free fatty acid and peroxide value of heated oils were increased gradually by the time pass whereas iodine value were decreased. After adding unheated oil to the heated oil, these values were restored to that of initial levels. On the other hand, content of polar components in the heated oil were directly related to the heating time. This result showed that polar compounds may be a clear indicator of used oils. Fatty acid composition in the used oils, unsaturated fatty acids such as linoleic and linolenic acid decreased while saturated fatty acid content increased with heating.

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A Survey on the Present State of Occurrence of Safety Accidents and Safety and Health Management Levels Among Swine Farmers (양돈 농가의 안전사고 발생현황 및 안전보건 관리수준)

  • Kim, Kyung-Ran;Kim, Insoo;Kim, Hyo-Cher;Lee, Kyung-Suk;Chae, Hye-Seon
    • Journal of Environmental Health Sciences
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    • v.40 no.5
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    • pp.413-424
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    • 2014
  • Objectives: The purpose of this study was to seek measures for improvement and management of farm work safety and health by conducting questionnaire surveys and on-site investigations to ascertain the present state of occurrence of safety accidents and safety and health management levels among swine farmers. In particular, the purpose of this study is to provide basic data for the establishment of measures for the management of safety and health suitable to the characteristics of related working environments. Methods: Questionnaire surveys were conducted among 223 farmers engaged in swine farming in 14 regions, and 10 farms were visited in order to implement multilateral methods, including in-depth interviews, along with field surveys. Results: The surveys indicated that 26.2% of all respondents experienced farm-work related safety accidents and body-reaction related accidents showed a high ratio at 31.1% of all respondents. With regard to cause materials of safety accidents, work other than that directly related to swine raising showed high ratios of safety accidents, with pigsty facility related accidents at 26.6%. Although most workers recognized the dangers latent in the working environments, their behavior and responses to the prevention of safety accidents were still insufficient due to a lack of understanding of safety and health management. In the survey on the present state of personal hygiene and wearing of protective equipment, workers were found to have been exposed to dangerous and harmful environments both inside and outside pigsties, but the actual states of their wearing protective safety equipment were very poor. Conclusion: Given the results of this study, swine farmers well recognize problems in their control of safety accidents and management of safety and health, but their knowledge about safety and health education and management guidelines was insufficient. Therefore, safety and health education, public relations, and customized personal protective equipment suitable for swine raising work should be developed in order to address the foregoing problem.