• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.4
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• pp.222-226
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• 2011

This study was conducted to identify the characteristics of analytical errors shown in the Korean quality control program on bulk asbestos analyses using polarized light microscopy (PLM). 179 participating laboratories were required to analyze 4 samples respectively and asked to classify each test sample as asbestos-containing (positive) or non-asbestos-containing (negative). For positive samples, participants were also asked to identify the type and semiquantitate the contents of asbestos present. The test results showed 21 (4%) false negative errors among 562 samples, 9 (6%) false positive errors among 154 samples and 53 (9%) asbestos identification errors among 562 samples. Most of false negative and positive errors were observed in a few types of samples. Higher frequencies of asbestos identification errors were shown in samples containing two or more types of asbestos and samples containing anthophyllite, tremolite or actinolite asbestos. For semiquantitative analyses, the ratios of mean to nominal weight contents were 2.1 for chrysotile and 2.9 for amphiboles. A tendency of over-estimation was observed in semiquantitative analyses using the visual estimation technique and higher in case of analyzing samples containing amphiboles than chrysotile. Coefficients of variation (CVs) of semiquantitative analytical results were 0.44~0.83 and 0.5~1.14 for samples containing chrysotile and amphibole asbestos, respectively.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.1
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• pp.35-40
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• 2013

Objectives: Asbestos contents of crushed serpentine rocks and airborne fiber concentrations of workers were determined at two serpentine quarries and a steel mill. Methods: Bulk samples of uncrushed and crushed serpentine rocks were collected and analyzed by PLM and TEM. Airborne asbestos samples were collected from the breathing zone of workers and the vicinity of working area and analyzed by PCM and TEM. Results: Chrysotile was identified with antigorite, lizardite and non-asbestiform actinolite in bulk samples. The arithmetic means of chrysotile contents in crushed serpentines were 0.11, 0.01, 0.42%(W/W) by quarry A, quarry B and a steel mill, respectively. The asbestos concentrations of all personal samples were less than 0.1 f/cc which is the permissible exposure limit of workers in Korea. The arithmetic means of airborne asbestos concentrations were 0.017 f/cc and 0.009 f/cc in personal samples collected from two serpentine quarries. The asbestos concentrations of all personal samples collected from a steel mill were less than LODs by PCM analysis but asbestos was detected in area samples by TEM. By the job tasks of serpentine quarries, crusher/separator operation generated the highest exposure to airborne asbestos. Conclusions: Although chrysotile contents in crushed serpentines of quarries were less the permissible level, the highest exposure of workers in serpentine quarries reached up to 76% of the permissible level of airborne asbestos. There were also possibilities of occupational exposure to airborne asbestos in a steel mill. The present exposure study should encourage further survey and occupational control of quarries producing serpentine or other types of asbestos-bearing rocks.

• Economic and Environmental Geology
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• v.47 no.5
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• pp.507-515
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• 2014

Asbestos is designated as carcinogen minerals. Detoxification of asbestos is being conducted by physical and chemical treatments that lead the formation of non-fibrous mineral particles or phase transitions. Major researches have been performed on mineralogical properties of asbestos and possibilities of detoxification in Korea. More specific studies are needed to prove the form and crystal structure changes during the detoxification of asbestos via heat treatment. Therefore, we studied thermal effects on mineralogical characteristics of chrysotile and asbestiform tremolite using electron microscopy investigation. Electron microscopy investigation showed chrysotile fibers were fully transformed into rod-shaped forsterite at $850^{\circ}C$ in 2 hours, and asbestiform tremolite fibers were converted into non-fibrous diopside at $1050^{\circ}C$ in 2 hours. Fibrous asbestos were converted into rod-shaped minerals, which are non-asbestiform. However, compositions of both minerals were not changed before and after heat treatment. These results indicate that thermal treatment of asbestos completely broke down asbestos structure due to dehydroxylation and recrystallization. Thus, electron microscopy investigation can provide the useful information of shapes, crystal structure, and chemistries of the asbestos for the detoxification.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.3
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• pp.139-145
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• 2011

Objectives: This investigation is purposed to evaluate the airborne asbestos concentrations in the public buildings having asbestos containing materials(ACMs) in Seoul. Methods: The Seoul Metropolitan Government carried out an asbestos survey to the city-owned public buildings to identify the level of risk exposure, classified into low, moderate and high risk. To evaluate the airborne concentration of asbestos, 11 sampling sites in ten buildings based on the survey were selected. The air samples from the eleven sites were analyzed by Phase Contrast Microscopy(PCM) and Transmission Electron Microscopy (TEM), and compared the analytical results from the both. Results: 1. The airborne fiber concentrations by PCM were less than the detection limit($7f/mm^2$) in 9(82%) out of 11 sampling sites. The highest concentration was 0.0043 f/cc, but it was below the guideline value for indoor air quality(0.01 f/cc), proposed by the Ministry of Environment, Korea. 2. In two sampling sites, having moderate risk level, the chrysotile was identified and showed it's concentrations of 0.0102 s/cc and 0.0058 s/cc, less than $5{\mu}m$ lengths. 3. The ACMs identified in the two sampling sites were a packing material(65% of chrysotile) in mechanical area and a thermal system insulation(5% of chrysotile) in a boiler room. Having more possibility of asbestos emission in the mechanical area, it would be required to set up and carry out the asbestos management plan. Conclusions: Based on the result of this study, the airborne asbestos concentrations in the public buildings with ACMs were generally lower than the guideline value for indoor air quality. There are widespread concerns about the possible health risk resulting from the presence of airborne asbestos fibers in the public buildings. Most of the previous studies about airborne asbestos analysis in Korea were performed based on PCM method that asbestos and non-asbestos fibers are counted together. In the public and commercial buildings, having ACMs, it is suggested that the asbestos be analyzed by TEM method to identify asbestos due to concerns about asbestos exposure to workers and unspecified people.

• Journal of Environmental Health Sciences
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• v.36 no.2
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• pp.163-169
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• 2010

All forms of asbestos are proven human carcinogens. All forms of asbestos cause malignant mesothelioma, lung, laryngeal, and ovarian cancers, and may cause gastrointestinal and other cancers. No exposure to asbestos is without risk, and there is no safe threshold of exposure to asbestos. Asbestos cancer victims die painful lingering deaths. These deaths are almost entirely preventable. When evidence of the carcinogenicity of asbestos became incontrovertible, concerned parties, including the Collegium Ramazzini, called for a universal ban on the mining, manufacture and use of asbestos in all countries around the world. Asbestos is now banned in 52 countries, and safer products have replaced many materials that once were made with asbestos. Nonetheless, a large number of countries still use, import, and export asbestos and asbestos-containing products. And still today in many countries that have banned other forms of asbestos, the so-called "controlled use" of chrysotile asbestos continues to be permitted, an exemption that has no basis in medical science but rather reflects the political and economic influence of the asbestos mining and manufacturing industry. To protect the health of all people in the world, industrial workers, construction workers, women and children, now and in future generations - the Collegium Ramazzini calls again today on all countries of the world, as we have repeatedly in the past, to join in the international endeavor to ban all forms of asbestos. An international ban on asbestos is urgently needed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.18 no.4
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• pp.271-281
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• 2008

This study is to characterize the occurrence types and mineralogical characteristics of asbestos for the Kwangcheon areas, Chungnam. The mine areas had been exploited as asbestos mines for several decades since 1930. Host rocks of the asbestos are serpentinites and altered rocks of the ultramafic rocks. Representative samples of the host rocks and minerals were sampled and were examined with microscopes. To confirm for the existences and compositions for the asbestos, the rock samples were analysed with EPMA, XRD and EDS. Chrysotile, tremolite and actinolite were found as asbestos and non-asbestos forms in these areas. Chrysotiles, as non-asbestos forms, occur in the host rocks with mesh and hourglass textures. They, as asbestos forms, are mainly found as the veins. The tremolite and actinolite, as asbestos types, occur as alteration products of the olivine and pyroxene within the host rocks. They, as asbestos types, are also found following the cracks and fractures. Overall results suggest that three types of the asbestos are found in the Kwangcheon and Kaewol mine areas. Based on the occurrence types for the asbestos, additional studies are required for the asbestos in the top soil and air.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.6
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• pp.703-712
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• 1999

In order to determine the number concentration of asbestos, it is initially necessary to develop a method to identify the type of asbestos. Thus a SEM/EDX was used to obtain both physical and chemical information from known asbestos samples as reference samples. Based on these information, we could make a source profile matrix consisted of a glass fiber and 3 other types of asbestos such as chrysotile, crocidolite, and tremolite. After collinearity test was performed for these sources, we could successfully develop an expert system by C-language to separate and to identify various unknown types of fiber particles. The expert system was perfectly self-verified with original reference data. Then the program was extensively applied to survey indoor and outdoor environment such as a residential area, an elementary school, and underground store, and an auto junkyard. As a result for surveying, a total of 442 individual fibrous particles were well classified into 4 types of particle classes above mentioned; 5.4% of chrysotile, 4.1% of crocidolite, 3.6% of glass fiber, and 86.9% of unknown fibers in terms of number concentration. However, tremolite was not detected in the study sites. All the samples were satisfied with the recommendation level of 0.01 f/cc.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.2
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• pp.127-138
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• 2009

Rock wool, a kind of asbestos substitutes, was analyzed for its physicochemical properties. After fivers of rock wool were instilled into rat lungs, These pathological changes were evaluated. In addition, the fibers in the lungs were counted and characterized after the lungs were treated for electron microscopical analysis. The lungs of rats showed pathological lesions such as granulomatous changes, but these lesions disappeared at 28 days groups after instilled rats. The rock wool fibers in the lungs decreased more 50 % after 28 days instilled into rat lungs. And rock wool showed early change in fiber compositions after 3 days compare with chrysotile showed after 7 days instilled into rat lungs. This study showed that the durability of rock wool in the lungs is more milder than chrysotile.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.11 no.2
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• pp.102-110
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• 2001

To establish an accurate asbestos analysis method for workplace samples, chrysotile, amosite, crocidolite, tremolite, actinolite, and anthophyllite asbestos fibers were analyzed for their morphology, atomic content and electron diffraction patterns. The morphology of asbestos fiber was evaluated in $10,000{\times}$ magnification. The atomic contents was analyzed by X-ray analyzer (TEM-EDX). Asbestos fibers were further assessed using electron diffraction (ED) patterns to provide an additional criterion for classifying the asbestos fibers. Twenty asbestos fibers were initially randomly selected for morphological evaluation; based on an aspect ratio (length : diameter = 3:1). Then the fibers were determined for their EDX spectrums and ED patterns. Our results showed that only chrysotile fiber has a hollow tube structure to be distinguished from other asbestos fibers. Although asbestos fibers had similar morphology, they had different EDX spectrums and ED patterns. Our results on the atomic content of asbestos fibers were very similar to those of other researchers, but amosite and crocidolite had a little difference in atomic content compared with the results from other researchers. The difference may be due to the difference in equipment or asbestos sample selection. A study on asbestos samples from biological specimens to establish a criterion for determining occupational asbestos exposed diseases should be done in the near future.

• Analytical Science and Technology
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• v.26 no.1
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• pp.91-98
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• 2013

Interested in NOA (Naturally Occurring Asbestos), Korea as well as the USA has been making geologic maps of asbestos distributed mines and surrounding areas, restoring mines, evaluating hazard, and so on. The result can be used to improve the reliability of analysts and analysis institutions by judging the amount of asbestos and set up PLM(Polarizing Light Microscope) information by analyzing in soil. The certification value of 2 kinds of CRM(Certified Reference Material) was performed by counting total 400 points with EPA 600-R-93-116 method using by PLM. The following is the result of homogeneity and stability of 2 kinds of manufactured CRM analyzed by ANOVA (Analysis of variance) and Regression Analysis. Based on the analyzation, the results are satisfied with homogeneity and long-term stability. The analyzed certification value of CRM includes the range of minimum and maximum value of point counting result for chrysotile; low concentration-1% (range, 0.25~3.00), high concentration-4% (range, 2.25~5.50).