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Modernising Asbestos testing with a desktop Scanning Electron Microscope Source: ATA Scientific
Safe Environments provides numerous services for clients Australia-wide, including slip testing, asbestos plus hazardous material testing, expert risk assessment and advice across a range of occupational health and safety services. The team has recently upgraded their laboratory by purchasing a Malvern Panalytical Epsilon x-ray fluorescence (XRF) and Aeris x-ray diffraction (XRD) systems, along with a Thermo Scientific Phenom XL G2 desktop Scanning Electron Microscope with energy-dispersive X-ray spectroscopy capabilities (SED-EDS). With this new equipment and their existing expertise in occupational hygiene, characterising hazardous dust and chemicals, Safe Environments has positioned itself to offer the most advanced testing available for health and safety issues. Characterisation of asbestos-containing materials is of great importance, whether it be a small home renovation or large-scale construction. Accurate identification and classification of commercial bulk materials, naturally occurring asbestos and airborne asbestos fibres is a critical part of managing the risk of exposure to workers and the community. Construction is often halted when the presence of asbestos is suspected, costing time and money. Rapid and accurate classification of the unknown fibres is essential to maintain a healthy work environment while ensuring the project continues. Traditional asbestos testing uses a combination of Phase Contrast Microscopy (PCM) and Polarised Light Microscopy (PLM), in addition to dispersion staining with oils of different refractive indices to the fibres being studied. Fibres interact with the polarised light due to their crystalline structure and the observed morphology of the fibres are used to classify potential asbestos types. This longstanding method is an industry standard that is a critical part of any asbestos testing laboratory. However, this technique which is part of the Australian Standard (AS4964) requires a method such as SEM with elemental analysis to be able to identify and confirm all six regulated types of asbestos. 32 | DECEMBER 2020
Traditional Polarised Light Microscopy (PLM) imaging, like that shown above, is a critical tool in identifying asbestos types but lacks the certainty that chemical analysis from Scanning Electron Microscope with energy-dispersive X-ray spectroscopy capabilities (SED-EDS) provides.
Traditional Polarised Light Microscopy (PLM) imaging, like that shown above, is a critical tool in identifying asbestos types but lacks the certainty that chemical analysis from Scanning Electron Microscope with energydispersive X-ray spectroscopy capabilities (SED-EDS) provides. When there is uncertainty in the results of the traditional techniques, the team at
Safe Environment turn to their Phenom SEM with EDS, particularly for cases of unknown mineral fibres. PCM which is used for counting fibres on an air filter does not differentiate between asbestos and nonasbestos fibres. The method simply counts the number of airborne fibres collected which have asbestos-like morphology. As a result, construction sites often shut down for days due to interfering respirable
Scanning Electron Microscope (SEM) images, like this one of Amosite from the Phenom XL G2, provide high-resolution shape and morphological information.
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