• Economic and Environmental Geology
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• v.57 no.5
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• pp.563-575
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• 2024

In Korea, talc, vermiculite, sepiolite, and serpentine were designated as minerals likely to contain asbestos (MLCA) according to the Ministry of Environment (Asbestos Safety Management Act). The asbestos content in commercial products made of MLCA must not exceed 0.1 %. In this study, mineralogical analyses using PLM, XRD, and TEM-EDS were used to characterize the presence, content, and morphological characteristics of asbestos in MLCA-containing commercial products. A total of 28 samples were analyzed, including 18 cosmetics containing talc, 5 fertilizers containing vermiculite, 2 pet sanitary products containing sepiolite, and 3 accessories containing serpentine. All samples were heated at 450 ℃ for 6 hours to remove organic matter prior to XRD and PLM analyses according to the Ministry of Environment guidelines. Additionally, the presence and morphology of elongated mineral particles (EMPs) were investigated using TEM-EDS analysis according to the recently revised asbestos analysis method (FDA-2020-N-0025) by the US FDA. The analyses showed that no asbestos was detected in both talc-containing cosmetics and sepiolite-containing products, but actinolite asbestos was found (<0.25 %) in vermiculite-containing fertilizers and chrysotile was found (<0.25 %) in decorative serpentine stones. In TEM-EDS analysis, multiple columnar/fibrous particles measuring 0.5 ㎛ or more in length were observed in talc-containing products, and short chrysotile fibers were observed in bracelets containing serpentine. Therefore, these results indicated that the MLCA-containing products that come into direct contact with the human body would require management through precise inspection and continuous monitoring considering EMPs of 5 ㎛ or less. Furthermore, TEM-EDS for asbestos analysis indicated that it could overcome the detection limits of XRD and PLM analyses for short or thin asbestos fibers, thereby improving the precision and accuracy of asbestos analysis.

• Economic and Environmental Geology
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• v.51 no.4
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• pp.309-322
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• 2018

Naturally occurring asbestos (NOA) occurs in rocks and soils as a result of natural weathering and human activities. It is proved that inhalation of asbestos fibers can lead to increase risk of developing several diseases such as lung cancer and malignant mesothelioma. The parent rocks of asbestos have been mainly associated with (ultra)mafic and carbonate rock. The previous studies on NOA were mainly limited to (ultra)mafic rock-hosted asbestos, but studies on carbonate rock-hosted asbestos are relatively rare in S. Korea. Therefore, this study was aimed to examine mineralogical characteristics of carbonate rock-hosted NOA at three sites including Muju and Jangsu, Jeonbuk province and Asan, Chungnam province. Types of rocks at the three sites mainly consisted of Precambrian metasedimentary rocks, carbonate rock, and Cretaceous and Jurassic granites. Asbestos-containing carbonate rock samples were obtained for mineralogical characterization. XRD, PLM, EPMA, SEM and EDS analyses were used to characterize mineralogical characteristics of the carbonate rock-hosted NOA. From the carbonate rock, fibrous minerals were occurred acicular and columnar forms in the three sites. Fibrous minerals were composed of mainly tremolite and associated minerals included possibly asbestos containing materials (ACM) such as talc, vermiculite, and sepiolite. The length and aspect ratios of tremolite were similar to the standard asbestiform (length >$5{\mu}m$, length:width = 3:1). These results indicate that both non-asbestiform and asbestiform tremolite with acicular forms occurred in carbonate rocks at three sites. Geological and geochemical characteristics and mineral assemblages indicate tremolite and associated minerals might be formed by hydrothermal alternation and/or hydrothermal veins of carbonate rocks due to intrusion of acidic igneous rocks.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.5
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• pp.345-350
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• 2012

To investigate the exposure and health risk assessment for the residents near the D-asbestos mine in Chungbuk, Korea. We analyzed asbestos in the 20 ambient air and 23 activity based samples near the mine. The airborne sample results are showed that 8 of 20 samples ranged between 0.0025 to 0.0029 f/cc (fiber per cubic centimeter) and the others were below the detection limit by phase contrast microscopy (PCM). In addition, asbestos fibers were under the detection limit or not being by transmission electron microscopy (TEM). Based on interview and survey targeting the local residents, we made the activity based sampling (ABS) scenarios fit to the conditions of field. At the same time, we calculated the excess lifetime cancer risk (ELCR) of these ABS scenarios according to the ELCR average value and 95% upper confidence limit (UCL). At the case of weed whacking, soil digging and sweeping yard scenario, 95% UCL of ELCR exceeded the $1{\times}10^{-4}$, acceptable risk range for exposure. Based on our study results, it is necessary safety measures such as risk communication, abatement or management of naturally occurring asbestos (NOA).