Analytical Transmission Electron Microscopy of Amphibole Fibers From the Lungs of Quebec Miners

Our plain-English summary of Analytical Transmission Electron Microscopy of Amphibole Fibers From the Lungs of Quebec Miners, by M. Germine, J.H. Puffer (Archives of Environmental & Occupational Health, 2015).

The study

• Authors: M. Germine, J.H. Puffer
• Journal: Archives of Environmental & Occupational Health
• Published: 2015;70(6):323-31
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The objective of this study is to describe the morphology, molecular structure, and chemistry of amphibole fibers from lung samples from workers in the chrysotile mines at Asbestos and Thetford Mines, Quebec. A fibrous tremolite-actinolite contaminant in an asbestos ore sample from the deposit at Asbestos was used for comparison. Lattice imaging was performed using high-resolution transmission electron microscopy (HRTEM). Silica-rich amorphous coatings (SIRA) that may be related to carcinogenesis are noted on all of the HRTEM photographs of fibers retained in lung, but not on fiber surfaces of the bulk comparison sample. Fibers found in lung samples and in a bulk comparison sample are produced primarily by splitting of thicker crystals and, as such, might not be considered asbestos fibers on the basis of certain mineralogical criteria. Implications of SIRA coatings with respect to carcinogenesis are worthy of further study.

In plain English

This exploratory laboratory study used high-resolution transmission electron microscopy and chemical analysis to examine amphibole fibers retained in the lungs of Quebec chrysotile mine production workers. Four microscope grids from four lung samples, from three workers, were analyzed in detail. Nine fibers from these grids were studied closely and compared with a bulk sample of fibrous tremolite-actinolite from the Jeffrey Mine. The lung fibers analyzed chemically were classified as tremolite-actinolite or actinolite, except one fiber that was intergrown tremolite-actinolite and anthophyllite. All lung fibers examined by high-resolution microscopy appeared to have silica-rich amorphous surface coatings, which the authors call SIRA. No such coatings were identified on the five comparison-sample fibers examined the same way. Crystal defects called chain multiplicity faults were common. The authors concluded that most fibers in the lungs and in the comparison sample were cleavage or parting fragments. They proposed that body fluids may cause the coatings to form. They noted that the coatings might instead have been present before the fibers entered the lungs or been produced by sample preparation, and that the number of samples was low.

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: Exploratory descriptive electron microscopy study (high-resolution TEM, electron diffraction and X-ray chemical analysis) of fibers recovered from lung tissue, with a bulk mineral comparison sample
• Who was studied: Four TEM grids from 4 lung samples from 3 deceased Quebec mine production workers (two samples from one worker, one sample each from two others), from the Thetford Mines and Asbestos areas. Nine fibers were studied in detail. The article states that the causes of death were not determined.
• Exposure: Work in Quebec chrysotile mines. The fibers studied were amphibole (tremolite-actinolite) fibers retained in lung. The comparison was a bulk sample of fibrous tremolite-actinolite from the Jeffrey Mine.
• Main results:
  • The chemically analyzed tremolitic fibers from lung samples could be classified only as actinolite and tremolite-actinolite. Table 2 lists fibers A2, E3 and O2 as tremolite-actinolite and fiber E1 as actinolite, although the Results text describes E-1 as tremolite-actinolite. One further fiber (E-2) was intergrown tremolite-actinolite and anthophyllite. Other fibers seen in the samples were chrysotile, antigorite, talc and sepiolite.
  • The text states that the chemically analyzed lung fibers were tremolite-actinolite except for the one intergrown fiber.
  • All lung fibers analyzed by high-resolution TEM appeared to have amorphous surface coatings (SIRA). Most analyses of these coatings detected only silicon and oxygen.
  • No SIRA coatings were identified on the 5 tremolite-actinolite fibers from the Jeffrey comparison sample examined by high-resolution TEM.
  • Chain multiplicity faults (a type of crystal-structure defect) were a common feature of the lung fibers.
  • In the Jeffrey comparison sample, 17 fibers were identified by diffraction and chemical analysis: 16 were tremolite-actinolite and 1 was augite.
• The authors' conclusion: The authors concluded that most fibers in the lungs of the Quebec mine workers and in the comparison sample were cleavage or parting fragments. They proposed that exposure to biological fluids can cause a porous SIRA coating to form on these fibers, and said more work is needed.
• Limitations the authors state:
  • The authors do not know all the effects that sample preparation had on the fibers.
  • The SIRA coatings may have been present on the fibers before they entered the lungs, or may have been produced by chlorine (bleach) digestion during preparation.
  • Few samples were studied and few quantitative analyses were done, because each quantitative analysis takes a long time.

Mines named here

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

• Bell Asbestos mine, Thetford Mines, Quebec
• Jeffrey mine, Asbestos, Quebec

All asbestos mines

Topics

The National Library of Medicine indexes this study under subjects our site covers: Actinolite, Lung cancer, Mesothelioma, Tremolite.

Medical terms in this study, explained in our Lexicon: Analytical Transmission Electron Microscopy (ATEM), Amphibole Group, Chrysotile, Thetford Mines, Tremolite, Actinolite, Transmission Electron Microscopy (TEM), HRTEM.

Related studies

• Tremolite-actinolite fiber coatings of sub-nanometer silica-rich particles in lungs from deceased Quebec miners — M. Germine, J.H. Puffer (2020)
• A technical comparison of evaluating asbestos concentration by phase-contrast microscopy (PCM), scanning electron microscopy (SEM), and analytical transmission electron microscopy (ATEM) as illustrated from data generated from a case report — R.F. Dodson, S.P. Hammar, et al. (2008)
• Assessment of occupational exposure to asbestos fibers: Contribution of analytical transmission electron microscopy analysis and comparison with phase-contrast microscopy — C. Eypert-Blaison, A. Romero-Hariot, et al. (2018)
• Comments on Dodson et al., A technical comparison of evaluating asbestos concentration by phase contrast microscopy (PCM), scanning electron microscopy (SEM), and analytical transmission electron microscopy (ATEM) as illustrated from data generated from a case report — V.L. Roggli, T.A. Sporn, et al. (2008)
• An inter-laboratory study to determine the effectiveness of procedures for discriminating amphibole asbestos fibers from amphibole cleavage fragments in fiber counting by phase-contrast microscopy — M. Harper, E.G. Lee, et al. (2012)
• Estimates of historical exposures by phase contrast and transmission electron microscopy for pooled exposure--response analyses of North Carolina and South Carolina, USA asbestos textile cohorts — J.M. Dement, D. Loomis, et al. (2011)

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