Mineral phases and some reexamined characteristics of the International Union Against Cancer standard asbestos samples

Our plain-English summary of Mineral phases and some reexamined characteristics of the International Union Against Cancer standard asbestos samples, by N. Kohyama, Y. Shinohara, Y. Suzuki (American Journal of Industrial Medicine, 1996).

The study

• Authors: N. Kohyama, Y. Shinohara, Y. Suzuki
• Journal: American Journal of Industrial Medicine
• Published: 1996;30(5):515-28
• Cited by: 56 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Standard asbestos samples to be used for biomedical research were first prepared by the International Union Against Cancer (UICC) in 1966 in the United Kingdom and South Africa. Using modern techniques, X-ray diffractometry, analytical transmission electron microscopy, and thermal analysis, we have now analyzed these UICC samples to determine the mineral compositions (mineral phases) and their respective quantities. UICC chrysotile A (from Zimbabwe) contains 2% fibrous anthophyllite as impurity; chrysotile B (from Canada) does not contain any fibrous impurities, only non-fibrous minerals. UICC amosite and crocidolite are almost pure. UICC anthophyllite has 20-30% talc as impurity. The chemical compositions and fiber size distributions of the UICC asbestos samples have also been determined. The mean widths of the fibers of chrysotile A and B are smaller than those of the amphibole fibers. This agrees well with the earlier results which showed the two chrysotile samples to have a larger respirable fraction than the amphiboles.

In plain English

This was a laboratory study of the five standard asbestos samples prepared by the International Union Against Cancer (UICC) in 1966: chrysotile A (from Zimbabwe), chrysotile B (from Canada), crocidolite and amosite (from South Africa) and anthophyllite (from Finland). The authors used X-ray diffraction, electron microscopy, and thermal and chemical analysis to identify the minerals and measure fiber sizes. Chrysotile A contained about 2% fibrous anthophyllite, while the other minerals found in the chrysotile samples were all non-fibrous. Chrysotile made up 94% of chrysotile A and 92% of chrysotile B. No tremolite was detected in either chrysotile sample, examined at the 0.1% level. Amosite and crocidolite contained about 1% or less quartz. The anthophyllite sample was estimated at 60% anthophyllite, 30% talc, 5% chlorite and 5% mica, an estimate the authors said had a relatively large error. Mean fiber widths were 0.17 and 0.15 micrometres for chrysotile A and B, compared with 0.31 to 0.38 micrometres for the three amphiboles. The authors suggested that some earlier reports had mistaken the anthophyllite in chrysotile A for tremolite. They concluded that their observations may require reevaluations.

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 mineralogical analysis of reference asbestos samples, using X-ray diffraction, analytical transmission electron microscopy, thermal analysis, chemical analysis and electron-microscope fiber size measurement
• Who was studied: The five UICC standard asbestos reference samples, prepared in 1966 in the United Kingdom and South Africa for biomedical research
• Exposure: UICC chrysotile A (Zimbabwe), chrysotile B (Canada), crocidolite (South Africa), amosite (South Africa) and anthophyllite (Finland)
• Main results:
  • Chrysotile A contained fibrous anthophyllite, estimated at approximately 2% (the X-ray estimate of 3% also included some talc)
  • Apart from the anthophyllite, the other minerals identified in the chrysotile samples were all non-fibrous, mostly platy
  • Chrysotile A was 94% chrysotile and chrysotile B was 92% chrysotile
  • No tremolite was detected in either chrysotile sample. Amphiboles in chrysotile A and B were looked for at the 0.1% level.
  • The amosite and crocidolite samples contained only very small amounts of quartz, about 1% or less by weight
  • The UICC anthophyllite sample was calculated to contain anthophyllite 60%, talc 30%, chlorite 5% and mica 5%
  • Mean fiber widths were 0.17 micrometres for chrysotile A and 0.15 micrometres for chrysotile B, compared with 0.31 to 0.38 micrometres for the three amphibole samples (amosite, crocidolite, anthophyllite)
  • The authors wrote that the narrower chrysotile widths seem to correlate well with earlier reports that the chrysotile samples had a larger respirable fraction than the amphiboles
  • Mean fiber lengths of chrysotile A, chrysotile B and crocidolite were slightly shorter than those of amosite and anthophyllite
  • UICC amosite and UICC crocidolite had similar fiber size distributions, which the authors noted contrasts with an earlier IARC publication suggesting crocidolite was several-fold thinner
  • The authors suggested that an earlier measurement of the respirable fraction of the anthophyllite sample would have been affected by talc contamination
  • The authors suggested that in some earlier reports the fibrous anthophyllite in chrysotile A had been mistaken for fibrous tremolite
• The authors' conclusion: The authors concluded that the purity findings (chrysotile A and B at 94% and 92% fiber, UICC anthophyllite at about 60%) may require reevaluations. They also said further study of Zimbabwe chrysotile miners and millers is needed to assess low-level amphibole contamination.
• Limitations the authors state:
  • Identifying and measuring talc in the anthophyllite sample by X-ray diffraction is very difficult because their peaks overlap
  • The calculation of talc and anthophyllite content has a relatively large error and gives only an approximate talc content
  • Repeated fiber size measurements on amosite and crocidolite showed fairly large variability in width and length

Topics

The National Library of Medicine indexes this study under subjects our site covers: Amosite, Anthophyllite, Chrysotile, Crocidolite.

Medical terms in this study, explained in our Lexicon: UICC, Analytical Transmission Electron Microscopy (ATEM), Chrysotile, Anthophyllite, Amosite, Crocidolite, Talc, Amphibole Group.

Related studies

• Lung mineral fibers of former miners and millers from Thetford-Mines and asbestos regions: a comparative study of fiber concentration and dimension — A. Nayebzadeh, A. Dufresne, et al. (2001)
• Pulmonary mineral fibers after occupational and environmental exposure to asbestos in the Russian chrysotile industry — A. Tossavainen, E. Kovalevsky, et al. (2000)
• Quantitative analysis of asbestos burden in women with mesothelioma — R.F. Dodson, M. O'Sullivan, et al. (2003)
• Asbestiform minerals in ophiolitic rocks of Calabria (southern Italy) — A. Campopiano, A. Olori, et al. (2018)
• A trial on the quantitative risk assessment of man-made mineral fibers by the rat intraperitoneal administration assay using the JFM standard fibrous samples — S. Adachi, K. Kawamura, et al. (2001)
• Asbestos and cancer; the report and recommendations of a working group convened under the auspices of the Geographical Pathology Committee of the International Union Against Cancer — F. Turgeon, J. Devries, et al. (1965)

Browse more research in American Journal of Industrial Medicine, or return to medical research.