Are Ferruginous Bodies An Indication Of Atmospheric Pollution By Asbestos?

Our plain-English summary of Are Ferruginous Bodies An Indication Of Atmospheric Pollution By Asbestos?, by J.M.G. Davies, P. Gross (1973).

The study

• Authors: J.M.G. Davies, P. Gross
• Published: Biological Effects Of Asbestos (J.C. Wagner, Editor), Lyon: Iarc Scientific Publications, Volume 8, Pp. 238-242 (1973)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library, J-M no. 004828. The article is still under copyright, so we describe it here rather than post it.

In plain English

This paper asked whether ferruginous bodies, which are iron-containing deposits formed around inhaled particles in lung tissue, can measure a community's airborne asbestos. The authors dissolved dried lung tissue from members of a normal urban population in Pittsburgh and Charleston, South Carolina, who had no known industrial asbestos exposure. They counted bodies and fibres by light and electron microscope, and noted that the number of lungs was not large. By light microscope, mineral fibres ranged from 15,000 to 400,000 per gram of dried lung, and ferruginous bodies from 28 to 4000 per gram. Fibres resembling chrysotile appeared in every case but averaged 9% of mineral fibres (highest 17%), and appearance alone was not fully diagnostic. The authors found no quantitative relation between ferruginous body and fibre counts. They concluded that ferruginous bodies do not qualify as an index of atmospheric asbestos pollution: they are not specific to asbestos, do not track fibre numbers, and people move between communities. In a preliminary animal experiment, injected short-fibred chrysotile (24 mg) was well tolerated. The authors said the hazard of fibres shorter than 5 micrometres was uncertain.

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 analysis of lung tissue from people without occupational exposure (descriptive series), presented within a discussion paper; also reports a preliminary animal injection experiment
• Who was studied: Lungs of members of a normal urban population in Pittsburgh, Pennsylvania and Charleston, South Carolina, with no known industrial exposure to asbestos; the authors describe the number of lungs as not large
• Exposure: Non-occupational (urban) exposure. The study measured total lung dust, ferruginous bodies, mineral fibres visible by light microscope, and fibres seen by electron microscope (longer than 5 micrometres, shorter than 5 micrometres, and fibres resembling chrysotile)
• Main results:
  • By light microscope, total mineral fibres in the lungs ranged from 15,000 to 400,000 per gram of dried lung
  • Ferruginous bodies ranged from 28 to 4000 per gram of dried lung tissue
  • Fibre content of the lungs bore no constant relationship to total lung dust content
  • By electron microscope, fibres more than 5 micrometres long ranged from 47 to 1950 per milligram of dried lung, and fibres under 5 micrometres from 106 to 4810 per milligram
  • Fibres that looked like chrysotile ranged from 7 to 1100 per milligram of dried lung
  • Fibres similar to chrysotile were found in all cases examined, but made up at most 17% and on average 9% of total mineral fibre
  • No quantitative relation was found between the number of ferruginous bodies and the number of fibres of any category
  • In a preliminary animal experiment, 24 mg of short-fibred chrysotile injected intratracheally was well tolerated, and the tissue response was a macrophage reaction without significant stromal proliferation
• The authors' conclusion: The authors concluded that ferruginous bodies do not qualify as an index of atmospheric pollution by asbestos, because they are not specific for asbestos, do not relate quantitatively to asbestos fibre numbers, and people in industrialised communities move between places. They also stated that the health hazard of asbestos fibres shorter than 5 micrometres was uncertain.
• Limitations the authors state:
  • The number of lungs with completed optical and electron microscope counts was not large
  • Identifying chrysotile by its appearance in the electron microscope is not completely diagnostic. Electron diffraction analysis to confirm true chrysotile was still under way.
  • The finding of no quantitative relation was described as a preliminary conclusion

Topics

Medical terms in this study, explained in our Lexicon: Ferruginous body, Asbestos Exposure, Chrysotile.

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