The nature of electron diffraction patterns of amphibole asbestos and their use in identification

Our plain-English summary of The nature of electron diffraction patterns of amphibole asbestos and their use in identification, by J.L. Hutchison, E.J. Whittaker (Environmental Research, 1979).

The study

• Authors: J.L. Hutchison, E.J. Whittaker
• Journal: Environmental Research
• Published: 1979;20(2):445-9
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This short technical paper looked at how to tell amphibole asbestos fibers (amosite, crocidolite and tremolite) apart using electron diffraction. That is a laboratory method that identifies a mineral from the pattern of spots made when an electron beam passes through a single fiber. The paper did not study people or health. Other researchers had reported that these patterns barely changed when fibers were tilted, and that the minerals were hard to distinguish. Drawing on their own earlier work, the authors argued that complex, unreadable patterns come from overly thick, probably composite fibers. Thin fibers, they said, give simple patterns that change on tilting in the predicted way. With the fiber in one particular orientation, amosite showed spots in very close pairs, about 0.02 reciprocal ångströms apart, on one row of the pattern. Crocidolite showed pairs about 0.05 apart. The difference could be seen without measuring. The authors said the method should in principle work for tremolite, but they had not found a suitably oriented or twinned tremolite fiber. The authors concluded that thin fibers give patterns that clearly tell the amphibole species apart.

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 technical commentary on an electron diffraction identification method, based on the authors' earlier published diffraction work and theoretical reasoning; not a health study
• Who was studied: Single fibers of amphibole asbestos minerals (amosite, crocidolite, tremolite) examined by selected-area electron diffraction; the number of fibers examined is not given
• Exposure: No human exposure studied; the subject is the identification of amphibole asbestos fiber types (amosite, crocidolite, tremolite) by electron diffraction
• Main results:
  • Complex, unindexable diffraction patterns came from excessively thick, probably composite fibers; thin fibers gave simple, indexable patterns
  • The simple patterns from thin fibers changed systematically on tilting, as predicted; some insensitivity to small tilts in certain orientations was explained by twinning
  • With the fiber's y axis parallel to the beam, spots on the third-layer line formed very close pairs for amosite and much more widely separated pairs for crocidolite
  • The spot-pair separation was about 0.02 reciprocal ångströms for amosite and about 0.05 for crocidolite (about 1/10 and 1/4 of the pattern's repeat distance), so the two could be told apart without measurement
  • In principle, tremolite would show a spot separation of 0.09 reciprocal ångströms on the third-layer line and very close pairs, only 0.01 apart, on the second-layer line
• The authors' conclusion: The authors concluded that the reported insensitivity to tilting does not occur when fibers are thin enough, that Seshan's explanation of it is incorrect, and that thin fibers give readily indexed patterns that clearly differentiate the amphibole species
• Limitations the authors state:
  • The authors had not been able to find a tremolite fiber in the needed orientation, nor any twinned tremolite fibers, so the tremolite identification was only theoretical
  • The authors' earlier paper did not deal explicitly with distinguishing the amphibole species

Topics

Medical terms in this study, explained in our Lexicon: Amphibole Asbestos.

Related studies

• Electron diffraction patterns of U.I.C.C. asbestos samples — M.I. Skikne, J.H. Talbot, et al. (1971)
• Explanation for the insensitivity to tilts of the electron diffraction patterns of amphibole asbestos fibers — K. Seshan (1977)
• Scanning electron microscopy and transmitted electron backscatter diffraction examination of asbestos standard reference materials, amphibole particles of differing morphology, and particle phase discrimination from talc ores — B.R. Bandli, M.E. Gunter (2014)
• An electron microscopy study of the effect of asbestos dust on the lung — J.M. Davis (1963)
• Effect of heat on the identification of asbestos by x-ray diffraction — C. Plowman (1973)
• Structural information in diffuse diffraction patterns — J.H. Konnert (1974)

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