Approaches and constraints to identification and quantitation of asbestos fibers

Our plain-English summary of Approaches and constraints to identification and quantitation of asbestos fibers, by A.M. Langer (Environmental Health Perspectives, 1974).

The study

• Author: A.M. Langer
• Journal: Environmental Health Perspectives
• Published: 1974;9:133-6
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001273).

Abstract

Asbestos fibers, members of complex crystal-chemical systems, possess some range in characteristic properties. Identification of fibers requires morphological, structural, and chemical data. Most current work centers on identification of single, sublight-microscopic fibers present as contaminants in a range of media. Constraints encountered in the analysis of such materials are: sample preparation of the differing media; level of fiber exposure (contamination); presence (kind and amount) of other particles; tissue types and their different preparation techniques; homogeneity of samples and their preparations; use of proper instrumental technique; time required for analysis, and quantitation.

In plain English

This 1974 article was a methods paper, not a study of a defined group of people. The author described how asbestos fibers too small for a light microscope are identified in air, liquids and tissues, and what makes this hard. The author explained that asbestos minerals vary; amosite, for example, belongs to a mineral series whose structure changes when magnesium content exceeds 70 mole-%. In the author's laboratory, digested lung tissue from asbestos workmen exposed to amphibole fiber showed some 100 to 500 uncoated fibers per electron microscope grid field. Similar lung preparations from people not occupationally exposed showed orders of magnitude less fiber per comparable area. Searching water samples was far harder than searching air filters, and characterizing 100 fibers from a water sample could take several weeks. The author's laboratory modified a laundry bleach digestion technique and reported routinely reducing any tissue for analysis. The author recommended electron beam instruments. The author concluded that the major constraint was the signal-to-noise ratio and that quantitation was only beginning; tissue quantitation was still being worked on, and counting should be automated.

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: Methods and commentary article describing approaches to, and constraints on, identifying and counting asbestos fibers. It includes a table comparing analytical instruments and some observations from the author's laboratory.
• Who was studied: No defined study population. The author describes laboratory examination of digested lung tissues from asbestos workmen and from people in the general population, without giving numbers of persons, places or dates.
• Exposure: Asbestos fibers in various media: air, liquids such as parenteral drugs, water, and human tissues. The lung tissue examples came from workmen exposed to amphibole fiber.
• Main results:
  • Amosite is a commercial term for a fiber in the cummingtonite-grunerite mineral series. When the mineral contains more than 70 mole-% magnesium, its structure changes from monoclinic to orthorhombic, and it is called anthophyllite.
  • In digested lung tissues from asbestos workmen exposed to amphibole fiber, some 100 to 500 uncoated fibers could be seen on each electron microscope grid field (an area of about 100 by 100 micrometers).
  • Similar lung preparations from people in the general population, not occupationally exposed, showed orders of magnitude less fiber per comparable area.
  • Even in asbestos workmen, organs other than the lung appeared to contain magnitudes less fiber than their lung tissues.
  • Searching for asbestos fiber on an air filter was far less difficult than on the same kind of filter for a water sample, because water may contain many other fibrous particles.
  • The author's laboratory slightly modified a tissue digestion technique using laundry bleach (sodium hypochlorite) and reported being able to routinely reduce any tissue for particle analysis.
  • Characterizing 100 fibers from a water sample may take several weeks of work, depending on fiber density relative to other particles.
  • Quantitation of asbestos fiber in tissue was still being worked on in the author's laboratory at the time.
  • Electron beam instrumentation was recommended for fiber analysis, even though the area searched is small and may not be representative, and each analysis takes much time.
• The authors' conclusion: The author concluded that the major remaining constraint was the signal-to-noise ratio: asbestos fiber coexisting with other particles, many of them fibrous. The author also stated that quantitation of asbestos fiber was only at the beginning stages and should be done by an automated technique.

Related studies

• Identification and quantitation of asbestos in talc — A.N. Rohl, A.M. Langer (1974)
• Techniques for the detection, identification and analysis of fibers — R.G. Keenan, J.R. Lynch (1970)
• Identification and quantitation of microparticles in solid materials — D.R. Bowes (1974)
• Quantitation of asbestos and asbestos-like fibers in human lung tissue by hot and wet ashing, and the significance of their presence for survival of lung carcinoma and mesothelioma patients — K. Kayser, C. Becker, et al. (1999)
• Identification of a particular amphibole asbestos fiber in tissues of persons exposed to a high oral intake of the mineral — R.E. Carter, W.F. Taylor (1980)
• Identification and enumeration of asbestos fibers in the mining environment: mission and modification to the Federal Asbestos Standard — A.M. Langer (2008)

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