Research Method for Sampling and Analysis of Fibrous Amphibole in Vermiculite Attic Insulation (EPA/600/R-04/004) January 2004
EPA has developed a research method for the analysis of fibrous amphibole in vermiculite attic insulation. This research method was developed to provide EPA with monitoring tools to study the occurrence and potential for exposure to fibrous amphibole associated primarily with vermiculite attic insulation produced from mines in the Libby, Montana, area. The research method is based on information provided by several experts who have been active in monitoring these materials, and the method is being considered by EPA for use in a research assessment of the exposure potential to fibrous amphibole from such insulation materials.
The method employs a separation of amphibole from vermiculite, using a flotation procedure. Vermiculite will float in a water suspension, while the denser amphibole will sink. Fibrous amphibole particles will separate from the material that sinks. The presence of fibrous amphibole is then confirmed by using available polarized light microscopy, scanning electron microscopy, or transmission electron microscopy protocols. The liquid used for the flotation may also be analyzed for fine fibrous amphibole by using either scanning electron microscopy or transmission electron microscopy.
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