Asbestos surface charge heterogeneity and biological effects

Our plain-English summary of Asbestos surface charge heterogeneity and biological effects, by W.G. Light (Science, 1981).

The study

• Author: W.G. Light
• Journal: Science
• Published: 1981;213(4515):1534
• Type of article: Letter
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This item was a short letter (technical comment) in Science. The author responded to a 1980 study by Schiller and colleagues reporting that blocky amphibole cleavage fragments carry a smaller net surface charge than elongated asbestos fibers. The author argued that slow dissolution (leaching) inside the body could change this charge over time. To test this, the author soaked crocidolite (an amphibole) fibers in Tyrode's solution, a physiological buffer, for various times. From fibers with an aspect ratio (length divided by diameter) of 5, the author estimated that the positive charge on the fiber ends would reach zero after 33 days. With further leaching, edges and faces would both become negatively charged. The original study's authors replied that there was no basis for assuming this pattern in biological systems, and that fiber measurements alone could not test it. The comment described no new human or animal experiments. It cited earlier studies by others reporting that glass fibers with larger length-to-diameter ratios, like crocidolite, induced a higher incidence of malignant pleural mesenchymal neoplasms than those with smaller ratios.

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: Letter (technical comment) with a small laboratory leaching experiment, followed by a reply from the authors of the original study
• Who was studied: Crocidolite fibers in the laboratory; no people or animals were studied. The number of fibers is not given.
• Exposure: Leaching of crocidolite (amphibole) fibers in Tyrode's physiological buffer solution for various times, followed by measurement of their electrophoretic mobility (surface charge)
• Main results:
  • For crocidolite fibers with an aspect ratio of 5, the author estimated that the basal (end) electrophoretic mobility would equal zero after 33 days of leaching.
  • The author estimated that with further leaching, both the edges and the faces of the crocidolite fibers would become negatively charged.
  • In their reply, Schiller, Payne and Khalafalla stated there was no basis for assuming that in biological systems the basal mobility varies with time while the lateral mobility stays constant.
  • The replying authors stated that mobility data from fibers alone are not enough to determine the effects of leaching separately on the two charge components.
  • This is a finding of earlier studies by others (reference 6), not of this comment: glass fibers, like crocidolite, with large aspect ratios induced a higher incidence of malignant pleural mesenchymal neoplasms than those with small aspect ratios.
• The authors' conclusion: The author concluded that long-term leaching in the body could erase the charge differences between fiber edges and faces. The author also noted, citing others' work on glass fibers, that factors other than edge and face charge differences would account for the observed variation in biological activity.

Related studies

• Surface charge heterogeneity in amphibole cleavage fragments and asbestos fibers — J.E. Schiller, S.L. Payne, et al. (1980)
• Surface charge and asbestos toxicity — W.G. Light, E.T. Wei (1977)
• Surface charge and hemolytic activity of asbestos — W.G. Light, E.T. Wei (1977)
• Free radical activity associated with the surface of particles: a unifying factor in determining biological activity? — K. Donaldson, P.H. Beswick, et al. (1996)
• Modification of biological surface activity of particles — R.J. Schnitzer (1974)
• Analysis of the biological and chemical reactivity of zeolite-based aluminosilicate fibers and particulates — E. Fach, W.J. Waldman, et al. (2002)

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