The distribution and characteristics of asbestos fibers in the lungs of Finnish anthophyllite mine-workers

Our plain-English summary of The distribution and characteristics of asbestos fibers in the lungs of Finnish anthophyllite mine-workers, by A. Morgan, A. Holmes (Environmental Research, 1984).

The study

• Authors: A. Morgan, A. Holmes
• Journal: Environmental Research
• Published: 1984;33(1):62-75
• Type of article: Case report
• Cited by: 31 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Measurements of the concentrations and dimensions of uncoated and coated fibers in blocks of tissue taken at the periphery and elsewhere from slices of lungs obtained from two anthophyllite-mine workers are reported. A single block from the lung of a third worker was also analyzed. For the subject examined in most detail, the mean peripheral fiber concentration was greatest in the lower lobe. In the other subject there did not appear to be much variation in fiber concentration with distance from the periphery. The count median lengths of uncoated fibers ranged from about 8 to 12 micron and for coated fibers from 40 to 50 micron. It was apparent that dicing tissue samples, before hypochlorite digestion, led to fracture of the longer uncoated and coated fibers. The results are compared with similar measurements made on the lung of an insulation worker and reported previously.

In plain English

This study measured asbestos fibers in lung tissue taken after death from three workers exposed to anthophyllite, two of whom had worked at the Paakkila anthophyllite mine in Finland. Subject A was diagnosed with incipient asbestosis the year before death and died of a heart attack. Subject B had asbestosis and died of severe atherosclerosis with a stroke. The third worker, heavily exposed, died of asbestosis. The authors dissolved blocks of lung tissue and counted uncoated and coated fibers by optical microscopy. In subject A, uncoated fibers averaged 33.9 million per gram of dry lung. The lower lobe's mean was 43% greater than the upper lobe's, and on average 11% of fibers were coated. Samples from the outer edges of subject B's lower lobe had similar concentrations. His upper lobe showed no clear trend with distance from the lung surface. The third worker's sample had higher concentrations than any sample from A or B. Median lengths were about 8 to 12 micrometers for uncoated fibers and 40 to 50 micrometers for coated fibers. Cutting tissue before dissolving it broke the longest fibers. The authors concluded that lung tissue must be sampled carefully and blocks digested whole.

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: Post-mortem lung tissue analysis: fiber concentrations and lengths counted by optical microscopy in tissue blocks from lung slices of three workers
• Who was studied: Two workers from the Paakkila anthophyllite mine, Finland, and a third worker who had been heavily exposed to anthophyllite. Subject A was aged 53 at death and had been a laborer for 30 years. He was diagnosed with incipient asbestosis the year before death and died of myocardial infarction. Subject B was aged 67 and had been a laborer for 24 years. He had asbestosis and died of severe atherosclerosis with cerebral infarction. The third worker died of asbestosis. Only a single tissue block was available from him.
• Exposure: Occupational exposure to anthophyllite asbestos (Paakkila mine for subjects A and B). The authors counted uncoated fibers longer than about 2 micrometers and coated fibers in lung tissue.
• Main results:
  • Subject A: the overall mean uncoated fiber concentration for all samples was 33.9 x 10^6 fibers per gram dry weight
  • Subject A: the mean fiber concentration in lower-lobe samples was 43% greater than in upper-lobe samples
  • Subject A: on average 11% of detected fibers were coated
  • Subject A, lower lobe: coated and uncoated fiber concentrations were correlated, with a correlation coefficient of 0.72 (P less than 0.001)
  • Subject A: in diced samples, uncoated fibers longer than 40 micrometers were invariably less than 6% of uncoated fibers. In samples not diced, they were 6 to 10.7%. This indicated that dicing broke long fibers.
  • Subject A: almost 100% of fibers longer than 80 micrometers were coated
  • In samples not diced before digestion, count median lengths of coated fibers were generally 40 to 50 micrometers
  • Subject B: mean concentrations in samples from the costal and diaphragmatic peripheral regions were very similar in magnitude to subject A's
  • Subject B, upper lobe: there was no apparent significant trend in fiber concentrations or dimensions with distance from the periphery
  • Third worker (subject C): concentrations of uncoated and coated fibers were greater than in any sample from subjects A or B
  • Subject C: the count median length of uncoated fibers was about 8 micrometers, less than for the other subjects
  • Fiber concentrations in adjacent tissue blocks varied by as much as a factor of five
• The authors' conclusion: The authors concluded that care is needed in sampling lung tissue to obtain an accurate estimate of mean fiber concentration. They also concluded that tissue blocks must be digested intact to avoid changing fiber dimensions and concentrations.
• Limitations the authors state:
  • The degree of fibrosis was not assessed in any subject
  • Optical microscopy may miss very short fibers, which may explain why median lengths were longer than in another study
  • Some samples were diced before digestion, and dicing broke long fibers
  • The comparison with a previously studied insulation worker used a different lung and a different slice orientation

Mines named here

Asbestos mines this study is about. Each mine's page says who ran it, when it worked, and what it produced.

• Paakkila mine, Finland

All asbestos mines

Topics

Medical terms in this study, explained in our Lexicon: Anthophyllite, Insulator.

Related studies

• Distribution and characteristics of amphibole asbestos fibres, measured with the light microscope, in the left lung of an insulation worker — A. Morgan, A. Holmes (1983)
• Four cases of mesothelioma among Finnish anthophyllite miners — A. Karjalainen, L.O. Meurman, et al. (1994)
• Combined effect of asbestos exposure and tobacco smoking on Finnish anthophyllite miners and millers — L.O. Meurman, R. Kiviluoto, et al. (1979)
• Amphibole fibers in a taconite mine and in the lungs of the miners — B. Gylseth, T. Norseth, et al. (1981)
• Clearance of anthophyllite fibers from the rat lung and the formation of asbestos bodies — A. Holmes, A. Morgan (1980)
• Discussion paper: asbestos fiber exposures in a hard rock gold mine — J.M. Dement, R.D. Zumwalde, et al. (1976)

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