The Konimiser--a dispenser for the continuous generation of dust clouds from milligram quantities of asbestos

Our plain-English summary of The Konimiser--a dispenser for the continuous generation of dust clouds from milligram quantities of asbestos, by R.F. Hounam (The Annals of Occupational Hygiene, 1971).

The study

• Author: R.F. Hounam
• Journal: The Annals of Occupational Hygiene
• Published: 1971;14(4):329-35
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This 1971 paper, by a single author at the Atomic Energy Research Establishment, Harwell, described the design, construction and performance of a small laboratory device called the "Konimiser". The device turns a few milligrams of asbestos into a steady cloud of dust small enough to be breathed in. It was not a study of people or of disease. The device was built for planned experiments in which rats would inhale radioactive asbestos, so that deposition and clearance in the airways could be studied. No animal results were reported. The device worked by pushing a small compressed plug of asbestos slowly into a fine air jet. The author tested it with four UICC standard reference samples (amosite, anthophyllite, chrysotile A and crocidolite) made radioactive in a reactor, running each sample twice. A reasonably constant dust concentration was kept for 1 to 2 hours. The share of each plug released as respirable fibre was highest for crocidolite (34 and 30 per cent) and lowest for anthophyllite (2.9 and 5.9 per cent). The author concluded the dispenser was suitable for dispersing small quantities of respirable radioactive asbestos for animal inhalation experiments.

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 methods paper describing the design, construction and performance testing of an asbestos dust dispenser (apparatus description; no human or animal outcomes)
• Who was studied: No people or animals were studied. The device was tested with UICC standard reference samples of asbestos at AERE Harwell, England, using duplicate runs with four samples. It was designed to work with an exposure chamber holding four rats in planned future experiments.
• Exposure: UICC standard reference samples of amosite, anthophyllite, chrysotile A and crocidolite, formed into plugs of a few milligrams and made radioactive by irradiation with thermal neutrons in a reactor
• Main results:
  • The dispenser produced and maintained a reasonably constant concentration of respirable fibre over 1 to 2 hours (shown for chrysotile A and amosite)
  • Efficiency of generation (share of the plug dispersed as respirable fibre) was highest for crocidolite, at 34 and 30 per cent in the two runs
  • Efficiency was lowest for anthophyllite, at 2.9 and 5.9 per cent in the two runs; the author thought this could possibly be improved
  • In Table 1, efficiency was 27 and 18 per cent for amosite and 12 and 13 per cent for chrysotile A. Mean concentrations were 22 and 17 mg per cubic metre for amosite, 3.5 and 5.3 for anthophyllite, 5.0 and 4.9 for chrysotile A, and 25 and 22 for crocidolite.
  • The efficiencies were not quite as high as, but compared favourably with, values reported by Timbrell et al. (1968) for a larger dispenser
  • Median fibre lengths in the clouds were 2.5 micrometres for amosite, 2.8 for anthophyllite, 4.1 for chrysotile A and 2.7 for crocidolite. This was about half the lengths derived from Timbrell (1971) for clouds from the same samples made by the larger dispenser.
  • On optical and electron microscopy, the airborne fibres appeared well dispersed
• The authors' conclusion: The author concluded that the dispenser is suitable for dispersing small quantities of respirable radioactive asbestos dust in animal inhalation experiments
• Limitations the authors state:
  • The efficiency for anthophyllite was low; the author suggested it might be improved
  • The fibre-length comparison with Timbrell's results may not be like-for-like. The author suggested the difference was probably because Timbrell measured an unelutriated cloud, which would contain longer fibres.

Related studies

• A simple dispenser for generating dust clouds from standard reference samples of asbestos — V. Timbrell, A.W. Hyett, et al. (1968)
• Enhanced generation of free radicals from phagocytes induced by mineral dusts — V. Vallyathan, J.F. Mega, et al. (1992)
• The early effects of chrysotile asbestos dust on the rat lung — P.F. Holt, J. Mills, et al. (1964)
• An electron microscopy study of the effect of asbestos dust on the lung — J.M. Davis (1963)
• Asbestos exposure: the dust cloud lingers — The Lancet Oncology (2019)
• Letter to the editor: "Comparing milled fiber, Quebec ore, and textile factory dust: has another piece of the asbestos puzzle fallen into place?" by D. Wayne Berman — J.M. Dement, L.T. Stayner (2010)

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