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Identifying the Reactive Sites of Hydrogen Peroxide Decomposition and Hydroxyl Radical Formation on Chrysotile Asbestos Surfaces

Overview
Publisher Biomed Central
Specialty Toxicology
Date 2020 Jan 22
PMID 31959185
Citations 3
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Abstract

Background: Fibrous chrysotile has been the most commonly applied asbestos mineral in a range of technical applications. However, it is toxic and carcinogenic upon inhalation. The chemical reactivity of chrysotile fiber surfaces contributes to its adverse health effects by catalyzing the formation of highly reactive hydroxyl radicals (HO) from HO. In this Haber-Weiss cycle, Fe on the fiber surface acts as a catalyst: Fe decomposes HO to reductants that reduce surface Fe to Fe, which is back-oxidized by HO (Fenton-oxidation) to yield HO. Chrysotile contains three structural Fe species: ferrous and ferric octahedral Fe and ferric tetrahedral Fe (Fe). Also, external Fe may adsorb or precipitate onto fiber surfaces. The goal of this study was to identify the Fe species on chrysotile surfaces that catalyze HO decomposition and HO generation.

Results: We demonstrate that at the physiological pH 7.4 Fe on chrysotile surfaces substantially contributes to HO decomposition and is the key structural Fe species catalyzing HO generation. After depleting Fe from fiber surfaces, a remnant fiber-related HO decomposition mode was identified, which may involve magnetite impurities, remnant Fe or substituted redox-active transition metals other than Fe. Fe (hydr)oxide precipitates on chrysotile surfaces also contributed to HO decomposition, but were per mole Fe substantially less efficient than surface Fe. Fe added to chrysotile fibers increased HO generation only when it became incorporated and tetrahedrally coordinated into vacancy sites in the Si layer.

Conclusions: Our results suggest that at the physiological pH 7.4, oxidative stress caused by chrysotile fibers largely results from radicals produced in the Haber-Weiss cycle that is catalyzed by Fe. The catalytic role of Fe in radical generation may also apply to other pathogenic silicates in which Fe is substituted, e.g. quartz, amphiboles and zeolites. However, even if these pathogenic minerals do not contain Fe, our results suggest that the mere presence of vacancy sites may pose a risk, as incorporation of external Fe into a tetrahedral coordination environment can lead to HO generation.

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The Potential Contribution of Hexavalent Chromium to the Carcinogenicity of Chrysotile Asbestos.

Walter M, Schenkeveld W, Tomatis M, Schelch K, Peter-Vorosmarty B, Geroldinger G Chem Res Toxicol. 2022; 35(12):2335-2347.

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References
1.
STEINHOFF D, Mohr U, HAHNEMANN S . Carcinogenesis studies with iron oxides. Exp Pathol. 1991; 43(3-4):189-94. DOI: 10.1016/s0232-1513(11)80116-7. View

2.
Le G, Takahashi K, Park E, Delgermaa V, Oak C, Qureshi A . Asbestos use and asbestos-related diseases in Asia: past, present and future. Respirology. 2011; 16(5):767-75. DOI: 10.1111/j.1440-1843.2011.01975.x. View

3.
ThomasArrigo L, Mikutta C, Byrne J, Kappler A, Kretzschmar R . Iron(II)-Catalyzed Iron Atom Exchange and Mineralogical Changes in Iron-rich Organic Freshwater Flocs: An Iron Isotope Tracer Study. Environ Sci Technol. 2017; 51(12):6897-6907. DOI: 10.1021/acs.est.7b01495. View

4.
Ghio A, Kennedy T, Whorton A, Crumbliss A, Hatch G, Hoidal J . Role of surface complexed iron in oxidant generation and lung inflammation induced by silicates. Am J Physiol. 1992; 263(5 Pt 1):L511-8. DOI: 10.1152/ajplung.1992.263.5.L511. View

5.
Dominguez-Vera J . Iron(III) complexation of Desferrioxamine B encapsulated in apoferritin. J Inorg Biochem. 2004; 98(3):469-72. DOI: 10.1016/j.jinorgbio.2003.12.015. View