Analysis of airborne dust samples for chrysotile by X-ray diffraction: interference by non-asbestiform serpentine

Our plain-English summary of Analysis of airborne dust samples for chrysotile by X-ray diffraction: interference by non-asbestiform serpentine, by A.P. Middleton (The Annals of Occupational Hygiene, 1982).

The study

• Author: A.P. Middleton
• Journal: The Annals of Occupational Hygiene
• Published: 1982;25(4):443-7
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This short technical note, by an author at TBA Industrial Products Ltd, dealt with a laboratory measurement problem rather than with disease. The author was investigating differences between results for chrysotile in airborne dust samples measured by transmission electron microscopy (TEM) and by X-ray diffraction (XRD). Dust samples collected in the grounds of an asbestos textile factory, and more samples collected near the source inside the factory, were examined by TEM with energy dispersive X-ray analysis. In both sets of samples, non-fibrous magnesium silicate particles gave electron diffraction patterns similar to those of antigorite and lizardite, which are non-asbestiform forms of serpentine. Lizardite could not be positively identified because it could be confused with talc. In dust collected near the source, more than 90% of non-fibrous particles were magnesium silicate. The author stated that the amount of non-fibrous serpentine was hard to estimate accurately. The author concluded that enough of these particles might be present to cause serious overestimation of chrysotile with conventional XRD geometry. The author suggested that XRD, being faster than electron microscopy, may perhaps still be useful for screening out non-occupational samples from areas with very low airborne concentrations.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Short laboratory methods note (mineral identification in air samples by electron microscopy and electron diffraction)
• Who was studied: Airborne dust samples collected in the grounds of an asbestos textile factory, plus additional samples collected near the source inside the factory. The note does not give the number of samples, the dates or the location.
• Exposure: Chrysotile in airborne dust, and non-fibrous magnesium silicate particles (non-asbestiform serpentine: antigorite and probably lizardite) that may interfere with XRD measurement of chrysotile
• Main results:
  • Electron diffraction patterns similar to those of antigorite and lizardite were found in both the factory-grounds samples and the near-source samples
  • Lizardite could not be positively identified because it could be confused with other layer silicates such as talc
  • In airborne dust collected near the source, more than 90% of non-fibrous particles were magnesium silicate by energy dispersive X-ray analysis
• The authors' conclusion: The author concluded that enough non-fibrous serpentine particles might be present to cause serious overestimation of chrysotile when conventional XRD geometry is used. The author also suggested, tentatively, that because it is faster than electron microscopy, XRD may perhaps be useful in the non-occupational environment for screening out samples from areas with very low airborne concentrations. The threshold figure is garbled in the scanned text.
• Limitations the authors state:
  • The mass of non-fibrous serpentine in the samples could not easily be estimated accurately
  • Talc may have been present in the original (factory-grounds) samples, so lizardite was identified only as probable

Topics

Medical terms in this study, explained in our Lexicon: Chrysotile, X-Ray Diffraction (XRD), Non-Asbestiform, Serpentine Group.

Related studies

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• Quantitative X-ray diffraction analysis of crocidolite and amosite in bulk or settled dust samples — J.V. Crable, M.J. Knott (1966)
• On the occurrence of fibres of calcium sulphate resembling amphibole asbestos in samples taken for the evaluation of airborne asbestos — A.P. Middleton (1978)
• A routine for the control of the performance of microscopists evaluating airborne asbestos fibre samples on membrane filters by phase contrast microscopy — J.R. Hoyes, R. Clayton (1980)
• Evidence and reconstruction of airborne asbestos from unconventional environmental samples — J.S. Webber, M. Getman, et al. (2006)
• Relative congener scaling of Polychlorinated dibenzo-p-dioxins and dibenzofurans to estimate building fire contributions in air, surface wipes, and dust samples — J.D. Pleil, M.N. Lorber (2007)

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