Interlaboratory evaluation of the breakup of asbestos-containing dust particles by ultrasonic agitation

Article Abstract:

Exposure to asbestos has been linked to a variety of respiratory illnesses. To determine the health risk posed by this material, the concentration of asbestos in the environment particularly on settled dust should be determined. Herein, a previous experiment using by the ASTM method is extended to include interlaboratory testing on asbestos-containing materials (ACM) and on simulated dusts containing ACM debris. The results reveal no significant differences in asbestos concentration for both samples. It is suggested that there is positive bias in the method and therefore, it cannot be considered quantitative.

Analysis

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Response to comment on "Effect of Indirect Sample Preparation Procedures on the Apparent Concentration of Asbestos in Settled Dusts." (reply to article by M.E. Beard, et. al. in this issue, p. 1404)

Article Abstract:

The American Society for Testing and Materials (ASTM) Standard Test Method D5755 for Microvacuum Sampling and Indirect Analysis of Dust by Transmission Electron Microscopy for Asbestos Structure Number Concentrations can neither be called quantitative nor standard. Though the method reports respirable fiber content, its outcome varies by several orders of magnitude, depending on the amount of large particles and on the processing parameters. Six issues concerning the ASTM protocol are contested and discussed.

Standards, ASTM, Asbestos in building, Asbestos building materials

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Effect of indirect sample preparation procedures on the apparent concentration of asbestos in settled dusts

Article Abstract:

The amount of asbestos in surface dust was measured using transmission electron microscopy to evaluate the effect of ultrasonication on the samples. It is shown that ultrasonication caused the asbestos to separate from the particles while breaking down unbound fibers into multiple structures. The type of starting material and the length of time for ultrasonication determined the degree of the effect.

Research, Usage, Ultrasonics, Transmission electron microscopes, Dust

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