Mössbauer Spectroscopy Indicates That Iron in an Aluminosilicate Glass Phase Is the Source of the Bioavailable Iron from Coal Fly Ash

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• 作者：John M. Veranth ; Kevin R. Smith ; Frank Huggins ; Autumn A. Hu ; JoAnn S. Lighty ; and Ann E. Aust
• 刊名：Chemical Research in Toxicology
• 出版年：2000
• 出版时间：March 2000
• 年：2000
• 卷：13
• 期：3
• 页码：161 - 164
• 全文大小：40K
• 年卷期：v.13,no.3(March 2000)
• ISSN：1520-5010

文摘

Iron speciation by Mössbauer spectroscopy indicates that ferric iron in an aluminosilicateglass phase is the source of the bioavailable iron in coal fly ash and that this iron species isassociated with combustion particles, but not with crustal dust derived from soil minerals.Urban particulate has been shown to be a source of bioavailable iron and has been shown tobe able to induce the formation of reactive species in cell culture experiments. Crustal dustand laboratory-generated coal fly ash have been studied as surrogates for two sources of metal-bearing particles in ambient air. As much as a 60-fold difference in the amount of iron mobilizedby the chelator citrate was observed between fly ash and crustal dust samples with similartotal iron contents. The extent of iron mobilization by citrate in vitro has been shown to correlatewith indirect measures of excess iron in cultured cells and with assays for reactive oxygenspecies generation in vitro. Mössbauer spectroscopy of coal fly ash, before and after treatmentwith the chelator desferrioxamine B, showed that the iron in an aluminosilicate glass phasewas preferentially removed. The removal of the glass-phase iron greatly reduced the amountof iron that could be mobilized by citrate and prevented the particles from inducing interleukin-8in cultured human lung epithelial (A549) cells. Ferric iron in aluminosilicate glass is associatedwith particles formed at high temperatures followed by rapid cooling. The observation thatferric iron in aluminosilicate glass is the source of bioavailable iron in coal fly ash suggeststhat particles from ambient sources and other specific combustion sources should be examinedfor the presence of this potential source of bioavailable iron.