Asbestos-induced decomposition of hydrogen peroxide

Our plain-English summary of Asbestos-induced decomposition of hydrogen peroxide, by M.K. Eberhardt, A.A. Román-Franco, M.R. Quiles (Environmental Research, 1985).

The study

• Authors: M.K. Eberhardt, A.A. Román-Franco, M.R. Quiles
• Journal: Environmental Research
• Published: 1985;37(2):287-92
• Cited by: 37 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Decomposition of H2O2 by chrysotile asbestos was demonstrated employing titration with KMnO4. The participation of OH radicals in this process was delineated employing the OH radical scavenger dimethyl sulfoxide (DMSO). A mechanism involving the Fenton and Haber-Weiss reactions as the pathway for the H2O2 decomposition and OH radical production is postulated.

In plain English

This was a laboratory chemistry experiment from the Puerto Rico Cancer Center. It tested whether chrysotile asbestos breaks down hydrogen peroxide, which cells release when engulfing fibers, and whether this produces hydroxyl radicals. No people, animals or cells were studied. The authors mixed 10 to 25 mg of chrysotile fibers with hydrogen peroxide in water and measured the peroxide over time. In water without asbestos, no breakdown was detected. With asbestos there seemed to be a short lag of about 2 hours, but by 24 hours a high percentage had broken down. In one set-up with 25 mg of fibers, 99% was gone after 48 hours. Shaking the vials and adding more fibers increased breakdown. Washing the fibers did not change the rate much, so the authors judged surface impurities an unlikely cause. With dimethyl sulfoxide, which gives off methane when it reacts with hydroxyl radicals, much more methane formed with asbestos than without, though some radicals also formed without it. The authors proposed a chemical mechanism and suggested that hydroxyl radicals formed this way could be partly responsible for cell damage in asbestos-induced diseases.

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 (test-tube) chemistry experiment; no human or animal subjects
• Who was studied: No people or animals. The material studied was chrysotile asbestos fibers from Borinquen Asbestos Corp., San Juan, Puerto Rico, about 5 to 100 micrometers long, tested at the Puerto Rico Cancer Center, University of Puerto Rico
• Exposure: 10, 20 or 25 mg of chrysotile asbestos in 2 ml of water (or 2 ml of dimethyl sulfoxide) with 100 microliters of 30, 3 or 0.3% hydrogen peroxide, left standing in the dark (some vials shaken). Peroxide was measured by titration; hydroxyl radicals were detected through the methane produced when they react with dimethyl sulfoxide
• Main results:
  • In the water (aqueous) tests with no asbestos, no hydrogen peroxide breakdown was detectable under any of the conditions tested
  • With asbestos there seemed to be a short induction period of about 2 hours, but after 24 hours a high percentage of the hydrogen peroxide had been broken down
  • With 25 mg of asbestos and 0.42 M hydrogen peroxide, 99% of the peroxide was broken down after 48 hours (Table 1)
  • Shaking the vials, which brought the fibers into closer contact with the solution, gave considerably more breakdown. More fibers also gave more breakdown
  • The breakdown rate did not vary significantly between unwashed fibers, water-washed fibers and fibers washed with ethanol and acetone. The authors judged that this made surface impurities an unlikely cause
  • Dimethyl sulfoxide reacts with hydroxyl radicals to give methyl radicals and then methane. In dimethyl sulfoxide, significant amounts of methane were produced with asbestos, and much smaller amounts without asbestos
  • In the dimethyl sulfoxide tests without asbestos, some hydrogen peroxide breakdown and some hydroxyl radical formation occurred, but no chain breakdown
• The authors' conclusion: The authors proposed that asbestos breaks down hydrogen peroxide through a chain reaction that probably involves an active metal-containing site on the fiber surface, and that produces hydroxyl radicals. They suggested that hydroxyl radicals formed by asbestos and hydrogen peroxide could be partly responsible for cell damage in asbestos-induced diseases.

Topics

Medical terms in this study, explained in our Lexicon: Chrysotile.

Related studies

• Identifying the reactive sites of hydrogen peroxide decomposition and hydroxyl radical formation on chrysotile asbestos surfaces — M. Walter, W.D.C. Schenkeveld, et al. (2020)
• Asbestos catalyzes hydroxyl and superoxide radical generation from hydrogen peroxide — S.A. Weitzman, P. Graceffa (1984)
• Different accumulation of activated extracellular signal-regulated kinases (ERK 1/2) and role in cell-cycle alterations by epidermal growth factor, hydrogen peroxide, or asbestos in pulmonary epithelial cells — S. Buder-Hoffmann, C. Palmer, et al. (2001)
• The release of iron from different asbestos structures by hydrogen peroxide with concomitant O2 generation — A.J. Ghio, D.E. Taylor, et al. (1998)
• Asbestos-induced lung epithelial permeability: potential role of nonoxidant pathways — M.W. Peterson, J. Kirschbaum (1998)
• In situ ESEM study of the thermal decomposition of chrysotile asbestos in view of safe recycling of the transformation product — A.F. Gualtieri, M.L. Gualtieri, et al. (2008)

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