Characterization and Properties of Asbestos Dust

Our plain-English summary of Characterization and Properties of Asbestos Dust, by A. Deruyttere, J. Helsen, J. Baeten (1980).

The study

• Authors: A. Deruyttere, J. Helsen, J. Baeten
• Published: BIOLOGICAL EFFECTS OF MINERAL FIBRES (J.C. WAGNER, EDITOR), LYON: IARC SCIENTIFIC PUBLICATIONS, VOLUME 30., PP 43-51 (1980)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This laboratory study compared dust from asbestos-cement products with pure asbestos and cement dust. The authors collected about 1 kg of dust from each of three machining operations on Belgian asbestos-cement products: sawing non-autoclaved sheet, sawing autoclaved sheet, and lathe-machining pipe. By weight, fine dust made up 12.5%, 19% and 52% of samples, and the calculated respirable fraction 8.5%, 10.5% and 35%, respectively. Among fine-dust particles, 6%, 1% and 10% were 'optically pure' asbestos fibres, and 38%, 24% and 32% were asbestos-cement aggregates. Electron microscopy showed a calcium signal on 'optically pure' chrysotile fibres from asbestos-cement dust that was absent in pure chrysotile. The authors wrote that these fibres appeared coated with a calcium-containing layer probably made of very small, closely spaced particles. All fibres examined from non-autoclaved sheet and pipe dust showed it, but not all from autoclaved sheet. In preliminary tests with two tobacco-smoke carcinogens, benzo[a]pyrene and maleic acid hydrazide, asbestos-cement dust adsorbed them more like hydrated cement than like chrysotile. The authors concluded that conclusions reached for pure asbestos dust should not automatically be applied to asbestos-cement dust.

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 characterizing dust from asbestos-cement products: particle sizing, electron microscopy with X-ray analysis, and adsorption experiments
• Who was studied: Dust samples (about 1 kg each) from three Belgian commercial asbestos-cement products: non-autoclaved sheet, autoclaved sheet and pipe. The samples came from machining operations as normally performed in an asbestos-cement production plant.
• Exposure: Dust produced by machining asbestos-cement products: sheets were sawn and pipe was machined on a lathe. The fibres analysed were chrysotile, compared with virgin chrysotile and hydrated cement.
• Main results:
  • Non-autoclaved sheet dust (Table 1): fine dust was 12.5% of total weight and respirable dust 8.5%. By number of fine dust, optically pure asbestos fibres were 6% and asbestos-cement aggregates 38%.
  • Autoclaved sheet dust (Table 1): fine dust 19% and respirable dust 10.5%; optically pure asbestos fibres 1% and asbestos-cement aggregates 24%
  • Pipe dust (Table 1): fine dust 52% and respirable dust 35%; optically pure asbestos fibres 10% and asbestos-cement aggregates 32%
  • Autoclaved sheet dust (Table 2): the calculated maximum admissible concentrations corresponding to 2 respirable fibres/ml were 0.6 mg/m3 for total dust and 0.06 mg/m3 for respirable dust. The authors note that the British Asbestos Regulations (1969) regard this fibre level as safe with regard to asbestosis.
  • Pipe dust (Table 2): the calculated maximum admissible concentrations corresponding to 2 respirable fibres/ml were 0.1 mg/m3 for total dust and 0.04 mg/m3 for respirable dust
  • The X-ray spectrum of an 'optically pure' chrysotile fibre from asbestos-cement dust showed a calcium peak that was not present in pure asbestos
  • The authors concluded that the calcium-containing layer on these fibres probably consists of very small particles lying close together
  • All fibres examined from non-autoclaved sheet and pipe dust showed a calcium layer. This was not the case for all fibres from autoclaved sheet dust.
  • Adsorption of benzo[a]pyrene by non-autoclaved and autoclaved sheet dust was close to that of hydrated cement dust and much lower than adsorption by pure chrysotile dust
  • Adsorption of maleic acid hydrazide by asbestos-cement dust was similar to that of hydrated cement and much higher than adsorption by chrysotile
• The authors' conclusion: The authors concluded that most asbestos fibres in asbestos-cement dust form aggregates with cement particles. They found that the 'optically pure' fibres appear coated with a calcium-containing layer that probably consists of very small particles. They wrote that these fibres may behave differently from pure asbestos, so conclusions reached for pure asbestos dust should not automatically be applied to asbestos-cement dust.
• Limitations the authors state:
  • The authors described the adsorption experiments as a preliminary investigation

Topics

Medical terms in this study, explained in our Lexicon: Asbestos-Cement, Respirable Fraction, Chrysotile.

Browse return to medical research.