Width Distributions of Asbestos and Non-Asbestos Amphibole Minerals

Abstract

Amphibole asbestos fibers and non-asbestos amphibole particles have been shown to have different size characteristics, in addition to their morphological differences. There is a tendency, however, among laboratories and some regulators to ignore the morphological differences and to simply rely on a minimal aspect ratio to determine whether a particle is an asbestos fiber. This study, part of a larger evaluation of amphibole minerals, was undertaken to provide supporting size data that can be used to identify populations of asbestos and non-asbestos amphibole minerals. The asbestos samples average 0.27 mm in width with 90% thinner than 0.5 mm. In contrast, the non-asbestos amphiboles average 0.97 mm wide with 75% wider than 0.53 mm. The average aspect ratios were 76 : 1 for asbestos and 16 : 1 for the nonasbestos samples. These data confirm the historical distinctions of asbestos and non-asbestos amphibole minerals.

Asbestos amphiboles: effects of comminution on tremolite and actinolite regulated and unregulated fibres

“…Finally, the aspect ratios vs. the diameters of the asbestiform amphiboles (samples F1, F2 and F3), were compared with those of nonasbestiform amphiboles (samples P1, P2 and P3). using a chart as in Van Orden et al (2009). This graph unequivocally highlights that, even after the comminution, the two type of samples show distinct, differences in distribution.…”

Asbestiform Amphiboles and Cleavage Fragments Analogues: Overview of Critical Dimensions, Aspect Ratios, Exposure and Health Effects

“…Applying the Chatfield [63] procedure for asbestos, A/R must be >20:1 and the width < 1.5 µm. In Van Orden et al [3,79] the asbestos samples have an average aspect ratio of 76:1 and a width of about 0.27 µm (90% thinner than 0.5 µm). Conversely, nonasbestos amphiboles have an average aspect ratio of 16:1 and a width of about 0.97 µm (75% wider than 0.53 µm).…”

Characterisation of chemically related asbestos amphiboles of actinolite: proposal for a specific differentiation in the diagram (Si apfu versus Mg/Mg+Fe2+)

“…These fibres are considered as coming from asbestiform minerals according to the data collected by Van Orden D.R. [27] In the diagram (Si apfu versus Mg/(Mg+Fe 2+ ) ( Fig. 6), the representative points of the fibres cover a compositional range close to that determined from the fibres retained in the first set (Fig.…”