Evaluation of Deposition and Clearance of Asbestos (Detected by SEM-EDS) in Lungs of Deceased Subjects Environmentally and/or Occupationally Exposed in Broni (Pavia, Northern Italy)

Our plain-English summary of Evaluation of Deposition and Clearance of Asbestos (Detected by SEM-EDS) in Lungs of Deceased Subjects Environmentally and/or Occupationally Exposed in Broni (Pavia, Northern Italy), by S.D. Visonà, S. Capella, S. Bodini, et al (Frontiers in Public Health, 2021).

The study

• Authors: S.D. Visonà, S. Capella, S. Bodini, P. Borrelli, S. Villani, E. Crespi, C. Colosio, C. Previderè, E. Belluso
• Journal: Frontiers in Public Health
• Published: 2021;9:678040
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Biodurability is one of the main determinants of asbestos hazardousness for human health. Very little is known about the actual persistence of asbestos in lungs and its clearance, nor about differences in this regard between the different mineralogical types of asbestos. The aim of the present study was to evaluate the amount, the dimensional characteristics and the mineralogic kinds of asbestos in lungs (measured using SEM-EDS) of a series of 72 deceased subjects who were certainly exposed to asbestos (mainly crocidolite and chrysotile) during their life. Moreover, we investigated possible correlations between the lung burden of asbestos (in general and considering each asbestos type), as well as their dimension (length, width, and l/w ratio) and the duration of exposure, the latency- in case of malignant mesothelioma (MM), the survival and the time since the end of exposure. In 62.5% of subjects, asbestos burden in lungs was lower that the threshold considered demonstrative for occupational exposure. In 29.1% of cases no asbestos was found. Chrysotile was practically not detected. The mean length of asbestos fibers and the length to width ratio were significantly related to the duration of exposure to asbestos. No other statistically significant correlations were found between the amount and dimensional characteristics of asbestos (nor with the relative amount of each asbestos type) and the other chronological variables considered. In conclusion, it was pointed out that chrysotile can be completely removed from human lungs in <8 years and, instead, amphiboles persist much more time. The present results suggest, as well, that the finding of no asbestos in lungs cannot rule out the attribution of MM to asbestos (in particular, chrysotile) inhaled in an occupational setting. This point is of crucial importance from a legal point of view.

Copyright © 2021 Visonà, Capella, Bodini, Borrelli, Villani, Crespi, Colosio, Previderè and Belluso.

In plain English

This retrospective study used electron microscopy (SEM-EDS) on autopsy lungs of 72 people from Broni, Italy, who died of malignant mesothelioma or asbestosis after documented exposure. They had lived near an asbestos-cement plant (using chrysotile and crocidolite, plus amosite as an additive), worked with asbestos, or both. In 62.5% of samples, asbestos was well below the threshold showing occupational exposure. None was found in 21 subjects (29.1%), 8 of them occupationally exposed. Chrysotile/asbestiform antigorite, which this method cannot separate, appeared in extremely low quantity in only one sample. Crocidolite (51%) and amosite (46%) made up most of the asbestos found. Fiber amount did not correlate significantly with exposure duration or time since exposure ended (at least 8 years), nor, among mesothelioma cases, with latency (first exposure to diagnosis) or survival after diagnosis. Longer exposure was related to longer mean fiber length and higher length-to-width ratio. The authors concluded that chrysotile can be completely removed from lungs after about 8 years and amphiboles persist long. The method missed fibers thinner than 0.2 micrometres; pleural tissue was not examined.

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: Retrospective study of autopsy lung samples analysed by scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS)
• Who was studied: 72 deceased people with a diagnosis of malignant mesothelioma or asbestosis, confirmed at forensic autopsy and histology. They were drawn from 188 eligible people who lived in Broni (Pavia, Northern Italy) or were occupationally exposed. A stratified random sample of 78 (26 environmental, 26 occupational, 26 both) was taken, and 6 occupational cases were excluded for technical reasons. The records came from the University of Pavia forensic archives, 2000 to 2018.
• Exposure: Anthropogenic environmental exposure (living near the Broni asbestos-cement plant), occupational exposure, or both. The plant's standard blend used chrysotile and crocidolite, with amosite as an additive. Occupational exposure lasted 6 to 480 months and environmental exposure 36 to 720 months.
• Main results:
  • In 62.5% of samples, the amount of asbestos detected was well below the threshold considered demonstrative for occupational exposure.
  • No asbestos was found in 21 subjects (29.1%) despite documented exposure; 8 of these had occupational exposure.
  • Fibers classified as chrysotile/asbestiform antigorite (which the method cannot distinguish) were detected, in extremely low quantity, in only one sample.
  • Of the total asbestos found, crocidolite made up 51%, amosite 46%, tremolite/actinolite asbestos 3.3% and anthophyllite asbestos 0.9%.
  • Across all subjects, the amount of asbestos fibers, and of each asbestos type, showed no significant correlation with duration of exposure, whether occupational or environmental.
  • In all 72 subjects, exposure had ended at least 8 years before death (median 21 years). The amount of asbestos did not correlate with time since the end of exposure.
  • In mesothelioma cases only, the amount of asbestos did not correlate with the latency period (first exposure to diagnosis).
  • In mesothelioma cases, survival time since diagnosis (1 to 379 months, median 15) was not related to the amount of asbestos in the lungs.
  • Mean fiber length and length-to-width ratio were positively related to duration of exposure.
  • Median fiber length, width and length-to-width ratio did not differ significantly among the three exposure groups (Kruskal-Wallis p = 0.764 for length, 0.818 for ratio).
  • All individuals with no detected asbestos in their lungs died of malignant mesothelioma.
• The authors' conclusion: The authors concluded that chrysotile can be completely removed from human lungs after about 8 years since the end of exposure, and that the study suggested long biopersistence of amphiboles.
• Limitations the authors state:
  • Only fibers longer than 5 micrometres, narrower than 3 micrometres and with a length-to-width ratio above 3 to 1 were counted. Fibers thinner than 0.2 micrometres could not be detected, and their pathogenicity cannot be ruled out.
  • Only lung fiber burden was measured, not pleural tissue.
  • The technique cannot distinguish chrysotile from asbestiform antigorite, or tremolite asbestos from actinolite asbestos.
  • Intensity of exposure varied between subjects and could not be exactly verified.

Topics

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

Medical terms in this study, explained in our Lexicon: Deposition, Crocidolite, Chrysotile, Latency, Mesothelioma, Occupational Exposure, Amphibole Group, Attribution.

Related studies

• Inorganic Fiber Lung Burden in Subjects with Occupational and/or Anthropogenic Environmental Asbestos Exposure in Broni (Pavia, Northern Italy): An SEM-EDS Study on Autoptic Samples — S.D. Visonà, S. Capella, et al. (2021)
• Reply to Mirabelli et al. Is Mesothelioma Unrelated to the Lung Asbestos Burden? Comment on "Visonà et al. Inorganic Fiber Lung Burden in Subjects with Occupational and/or Anthropogenic Environmental Asbestos Exposure in Broni (Pavia, Northern Italy): An SEM-EDS Study on Autoptic Samples. Int. J. Environ. Res. Public Health 2021, 18, 2053" — S.D. Visonà, S. Capella, et al. (2021)
• Asbestos burden in lungs of non-occupationally exposed women from Broni (Pavia, Italy): a postmortem SEM-EDS study — S.D. Visonà, S. Capella, et al. (2023)
• Is Mesothelioma Unrelated to the Lung Asbestos Burden? Comment on Visonà et al. Inorganic Fiber Lung Burden in Subjects with Occupational and/or Anthropogenic Environmental Asbestos Exposure in Broni (Pavia, Northern Italy): An SEM-EDS Study on Autoptic Samples. Int. J. Environ. Res. Public Health 2021, 18, 2053 — D. Mirabelli, A. Angelini, et al. (2021)
• Impact of asbestos on public health: a retrospective study on a series of subjects with occupational and non-occupational exposure to asbestos during the activity of Fibronit plant (Broni, Italy) — S.D. Visonà, S. Villani, et al. (2018)
• Asbestos Burden in Lungs of Subjects Deceased From Mesothelioma Who Lived in Proximity to an Asbestos Factory: A Topographic Post-Mortem SEM-EDS Study — S.D. Visonà, M. Untalan, et al. (2025)

Browse more research in Frontiers in Public Health, or return to medical research.