Mineral particles in the lungs of subjects resident in the Rome area and not occupationally exposed to mineral dust

Our plain-English summary of Mineral particles in the lungs of subjects resident in the Rome area and not occupationally exposed to mineral dust, by L. Paoletti, D. Batisti, S. Caiazza, et al (Environmental Research, 1987).

The study

• Authors: L. Paoletti, D. Batisti, S. Caiazza, M.G. Petrelli, F. Taggi, L. De Zorzi, M.A. Dina, G. Donelli
• Journal: Environmental Research
• Published: 1987;44(1):18-28
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

We studied the inorganic particulate contained in the lung parenchyma of 10 subjects (5 males and 5 females) resident in an urban area and not occupationally exposed to dusts. A total of 17 mineral types were identified, along with 16 metal elements in the form of oxides and sulfides. Approximately 70% of the minerals were made up of phyllosilicates, in particular clay, mica, and talc; three metal elements, Fe, Al, and Ti, accounted for more than 75% of the recovered oxide particles. The mean concentration of the observed inorganic particles was approximately 1.8 X 10(5) pp/mg dry tissue. No significant differences were observed in terms of total particulate concentration in the various areas of the lungs and between the right and left lung. Instead we observed a larger concentration of fibrous particles in the upper lobes. The analysis of the data made it possible to determine the presence of a high degree of correlation between the concentrations of silicates and the concentrations of metal oxides and sulfides, implying the existence of a ubiquitous environmental source of these mineral particles. The frequent observation of tremolite fibers is remarkable. This finding, confirmed elsewhere, indicates that the magnitude of the sources of these fibers in the environment, constituted by contaminated talc dusts, has been underestimated until today.

In plain English

This study examined mineral particles in lung tissue from 10 people, 5 men and 5 women. All had died at a hospital in the Rome metropolitan area, lived in the urban area, and had not been exposed to mineral dust at work. Tissue from six sites in each person's lungs was analyzed with a transmission electron microscope. The authors identified 17 mineral types and 16 metals present as oxides or sulfides. Micas, clays, talcs and silicon oxides made up about 90% of the mineral particles. Mean concentrations were 1.97 x 10^5 particles per mg of dry tissue in the right lung and 1.71 x 10^5 in the left. Asbestos fibers were found in 7 of the 10 people, and tremolite in 5 of them. Crocidolite and chrysotile were also seen. Asbestos fibers tended to collect in the upper lung areas. Asbestos levels did not correlate with total particle levels (coefficient 0.44), and talc levels correlated weakly with tremolite levels (0.22). The authors concluded that environmental sources of tremolite, made up of contaminated talc dusts, had been underestimated. They also noted that their sample was small.

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: Analysis of lung tissue taken from people who had died in hospital (an autopsy lung-content study of 10 cases), using transmission electron microscopy with electron diffraction and X-ray microanalysis
• Who was studied: 10 deceased subjects (5 males, 5 females, aged 20 to 83) who lived in the Rome urban area and were not occupationally exposed to dusts; six lung sites were sampled per subject
• Exposure: General urban environmental exposure with no occupational dust exposure; the study measured inorganic particles retained in the lungs, including silicates, metal oxides and sulfides, and asbestos fibers (tremolite, crocidolite, chrysotile)
• Main results:
  • Across all 10 subjects, 17 mineral varieties and 16 metal elements (as oxide or sulfide particles) were identified
  • Micas, clays, talcs and silicon oxides made up about 90% of all mineral particles observed
  • Mean mineral particle concentration in all 10 subjects was 1.97 x 10^5 particles per mg dry tissue in the right lung and 1.71 x 10^5 in the left lung
  • Asbestos fibers were recovered from 7 of the 10 subjects
  • Tremolite was found in 5 of the 10 subjects
  • Tremolite, crocidolite and chrysotile fibers were between 1 and 8 micrometers long
  • Silicate and silicon oxide concentrations correlated closely with metal oxide and sulfide concentrations (coefficient 0.84)
  • The authors described the relationship between asbestos fiber concentration and total mineral particle concentration as no correlation (coefficient 0.44)
  • The correlation coefficient between talc and tremolite fiber concentrations was 0.22
  • Asbestos fibers tended to accumulate in the upper lung areas
  • Regular smokers of more than 10 cigarettes a day had higher-than-average mineral particle concentrations, with increases of up to 25%
  • The one subject who died of lung cancer had the highest mineral particle concentration, but that subject's asbestos fiber concentration was not remarkably different from the others
• The authors' conclusion: The authors concluded that the frequent finding of tremolite indicates that environmental sources of tremolite, made up of contaminated talc dusts, had been underestimated. They also concluded that the data suggest a larger population sample could be used to characterize the urban environment.
• Limitations the authors state:
  • The sample studied was small
  • Some iron oxide particles may have come from the lung tissue itself rather than from the environment, but they were counted anyway
  • No heavy smokers were included

Topics

Medical terms in this study, explained in our Lexicon: Parenchyma, Phyllosilicates, Mica, Talc, Silicate, Tremolite.

Related studies

• Coated and uncoated lung mineral fibres in subjects with and without pleural plaques at autopsy — A. Andrion, D. Bellis, et al. (1984)
• Interleukin 1 production and accessory cell function of rat alveolar macrophages exposed to mineral dust particles — Y. Oghiso, Y. Kubota (1987)
• Inhalation toxicity of mineral particles: critical appraisal of endpoints and study design — H. Muhle, I. Mangelsdorf (2003)
• Pulmonary mineral dust. A study of ninety patients by electron microscopy, electron microanalysis, and electron microdiffraction — J.P. Berry, P. Henoc, et al. (1976)
• Mineral dusts directly induce epithelial and interstitial fibrogenic mediators and matrix components in the airway wall — J. Dai, B. Gilks, et al. (1998)
• Reaction of mineral dusts with primary lung fibroblast cultures — R.J. Richards, J. Hunt (1983)

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