Electron diffraction patterns of U.I.C.C. asbestos samples

Our plain-English summary of Electron diffraction patterns of U.I.C.C. asbestos samples, by M.I. Skikne, J.H. Talbot, R.E. Rendall (Environmental Research, 1971).

The study

• Authors: M.I. Skikne, J.H. Talbot, R.E. Rendall
• Journal: Environmental Research
• Published: 1971;4(2):141-5
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The U.I.C.C. standard samples of amosite, anthophyllite, crocidolite, chrysotile A, ;und chrysotile B have been studied by electron diffraction. The effect of fibre orientation on the electron diffraction patterns was studied using a double-tilt stage. Rotation did not have a nurked effect on the general pattern of weak and strong spectra. It has been shown that electron diffraction nlethod may ha nsed to identify Sin& fib-es of the samples.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This was a laboratory study of mineral samples, not a study of people. The authors examined the U.I.C.C. standard reference samples of amosite, anthophyllite, crocidolite, chrysotile A (Rhodesian) and chrysotile B (Canadian) using electron diffraction. Their aim was to obtain data for identifying fibres collected from the air and from biological tissues. All five samples gave single-fibre patterns made of straight parallel rows of spots. The spacing between rows was the same for all five. Crocidolite showed alternating long and short spacings, corresponding to periods of 1.66 and 2.16 nm. Amosite and anthophyllite showed equal spacings corresponding to 1.80 nm, so crocidolite could be told apart readily. Amosite patterns were more variable than anthophyllite patterns. The anthophyllite sample contained considerable quantities of a sheet silicate, probably mica or talc. Tilting the fibres changed the relative intensities of the spots, but the general patterns were preserved. Chrysotile fibres were usually curved and occurred in bundles, and their patterns showed arced spots and in some cases rings. Both chrysotile samples gave similar patterns. The authors concluded that in most cases individual fibres of amosite, anthophyllite, crocidolite and chrysotile can be identified this way.

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: Laboratory study of standard asbestos mineral samples using electron diffraction in an electron microscope (no human or animal subjects)
• Who was studied: The U.I.C.C. standard reference asbestos samples: one sample each of amosite, anthophyllite and crocidolite (amphiboles), and two chrysotile samples, chrysotile A (Rhodesian) and chrysotile B (Canadian). The work was done at the Pneumoconiosis Research Unit, Johannesburg, South Africa.
• Exposure: No exposure was studied. The materials were fibres of amosite, anthophyllite, crocidolite and chrysotile. They were examined by selected-area electron diffraction of circular areas 1 micrometre in diameter on an AEI EM 801 microscope. A double-tilt stage was used to rotate fibres up to 30 degrees about axes parallel and perpendicular to the fibre axis.
• Main results:
  • All five U.I.C.C. samples gave single-fibre diffraction patterns of straight parallel rows of spots. The spacing between rows was the same for all five samples.
  • Crocidolite spots showed alternating long and short spaces corresponding to periods of 1.66 and 2.16 nm. In amosite and anthophyllite the spots in each row were equally spaced, corresponding to a period of 1.80 nm. Crocidolite could therefore be distinguished readily from amosite and anthophyllite.
  • Most anthophyllite fibres showed a distinctive pattern of strong spots. The anthophyllite sample contained considerable quantities of a sheet silicate, probably mica or talc.
  • Amosite patterns were more variable and lacked the distinctive strong-spot pattern seen in anthophyllite. The authors used the arrangement of intense spots to distinguish amosite from anthophyllite.
  • Rotating fibres changed the relative intensities of the spots, but the general patterns were preserved whatever the orientation.
  • Chrysotile fibres were usually curved and occurred in bundles. Their patterns showed arcing of the spots and in some cases rings. The two chrysotile samples (A and B) gave similar patterns, which the authors took to indicate the minerals are probably the same.
• The authors' conclusion: The authors concluded that in most cases individual fibres of amosite, anthophyllite, crocidolite and chrysotile can be identified by electron diffraction. In their view, the three amphiboles closely resemble each other but can generally be distinguished by spot spacing and intensity patterns, and chrysotile has a distinctive appearance and pattern.
• Limitations the authors state:
  • For chrysotile, individual fibres could only rarely be isolated for diffraction, because most fibres occurred in open bundles.

Topics

Medical terms in this study, explained in our Lexicon: Amosite, Anthophyllite, Crocidolite, Chrysotile.

Related studies

• The nature of electron diffraction patterns of amphibole asbestos and their use in identification — J.L. Hutchison, E.J. Whittaker (1979)
• Explanation for the insensitivity to tilts of the electron diffraction patterns of amphibole asbestos fibers — K. Seshan (1977)
• An electron microscopy study of the effect of asbestos dust on the lung — J.M. Davis (1963)
• Analysis of airborne dust samples for chrysotile by X-ray diffraction: interference by non-asbestiform serpentine — A.P. Middleton (1982)
• The ultrastructure of asbestos bodies from guinea-pig lungs — J.M. Davis (1964)
• The ultrastructure of asbestos bodies from human lung — J.M. Davis (1964)

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