Evaluation of a fluidized bed asbestos segregator preparation method for the analysis of low-levels of asbestos in soil and other solid media (original) (raw)
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2005
Quantitative determination of asbestos in rocks and soils by optical microscopy: analytical methods and examples of application / CAZZOLA C; CLERICI C; FRANCESE S; PATRUCCO M; ZANETTI G.; GALLARA' F. (2005), pp. 34-36. ((Intervento presentato al convegno AMAM 2005 International Conference on Asbestos Monitoring and Analytical Methods tenutosi a Venezia nel 5 7 dicembre 2005. Original Quantitative determination of asbestos in rocks and soils by optical microscopy: analytical methods and examples of application
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2017
The quantification of NOA (Naturally Occurring Asbestos) in a rock or soil matrix is complex and subject to numerous errors. Current legislation in Italy (DM 6/9/94) defines the threshold of 1000 mg/kg of asbestos fibers on the total of the material, beyond which the material is considered as hazardous waste. The objective of this study is to compare two fundamental techniques for analysis: the first one is based on analysis with a Phase Contrast Optical Microscope (PCOM) while the second one requires the use of a Scanning Electron Microscope (SEM). In order to provide a sufficiently reliable uncertainty of the PCOM methodology, 10 repetitions of the analysis by two different operators on two selected samples were carried out. Another important part of this study is the comparison between SEM and PCOM analysis. Over 100 tests have been performed to date on natural samples from both cores and from excavation materials with the use of the two techniques. A good correlation between the...
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The Concentration of Asbestos Fibers in Bulk Samples and Its Variation with Grain Size
Minerals
The aim of this work was to establish whether asbestos fibers homogeneously occur in the different fractions ground from naturally occurring asbestos lithotypes, and to calculate the contribution of fibers from each fraction to the overall concentration in the sample. Serpentinite, metabasalt, calc-schist, clay, debris material, and soil, were addressed. Grain size fractions below 20 mm were sieved at 2 mm and 0.106 mm; they were then were mechanically milled to obtain powders below 0.106 mm. The three powdered fractions were characterized using a scanning electron microscope coupled with energy dispersive spectroscopy following M.D. 06/09/94. The still in use (in some cases), Italian normative M.D. 161/2012 specifies that analyses must be performed on the <2 mm fraction and the concentration (mg/kg) correlated with the weight of the whole sample <20 mm. However, the fiber counts yielded asbestos concentrations 50–60% lower compared with total asbestos analyses according to th...
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Bulletin of the Geological Society of Greece, 2017
This study focuses on the quantification of asbestiform minerals in basic and ultrabasic rocks from ophiolite suites of central and northern Greece. A combination of different methods were used for the detailed investigation of the samples, conducted in the following stages: (i) petrographic examination of thin sections with a polarizing microscope, (ii) mineral phase analysis using X-ray diffraction, (iii) determination of the fibrous mineral composition on polished thin sections using scanning electron microscopy, (iv) image analysis of back scattered electron images and secondary electron images, to quantify the dangerous asbestiform crystals. SEM is proved to be the most powerful tool for the detailed investigation of fibrous minerals, although polarized microscopy and XRD are necessary tools for a preliminary identification of these minerals. Basic rocks contain various amounts of actinolite, however not all crystals comprise asbestiform fibres. A conspicuous feature observed d...
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