Discovery and potential ramifications of reduced iron-bearing nanoparticles—magnetite, wüstite, and zero-valent iron—in wildland–urban interface fire ashes

Baalousha, Mohammed; Desmau, Morgane; Singerling, S. A.; Webster, Jackson P.; Matiasek, S. J.; Stern, Michelle; Alpers, Charles N.

doi:10.1039/d2en00439a

Cited by 11 publications

(5 citation statements)

References 85 publications

(135 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Suburban fires illustrates the impacts of inhaling Cr(VI)-containing ash within the respiratory tract by measuring Cr(VI) leached with a simulated lung fluid 36 , 37 and discerning Cr mineralogy within nano-sized particulates (<100 nm) 27 , 29 . Our results indicate that comparable toxic levels of reactive (water-soluble) Cr(VI) are formed within a serpentine wildland landscape as previously observed from structural burning 36 , 37 (Fig.…”

Section: Resultsmentioning

confidence: 99%

Metal toxin threat in wildland fires determined by geology and fire severity

Lopez,

Pacheco,

Fendorf

2023

Nat Commun

View full text Add to dashboard Cite

Accentuated by climate change, catastrophic wildfires are a growing, distributed global public health risk from inhalation of smoke and dust. Underrecognized, however, are the health threats arising from fire-altered toxic metals natural to soils and plants. Here, we demonstrate that high temperatures during California wildfires catalyzed widespread transformation of chromium to its carcinogenic form in soil and ash, as hexavalent chromium, particularly in areas with metal-rich geologies (e.g., serpentinite). In wildfire ash, we observed dangerous levels (327-13,100 µg kg−1) of reactive hexavalent chromium in wind-dispersible particulates. Relatively dry post-fire weather contributed to the persistence of elevated hexavalent chromium in surficial soil layers for up to ten months post-fire. The geographic distribution of metal-rich soils and fire incidents illustrate the broad global threat of wildfire smoke- and dust-born metals to populations. Our findings provide new insights into why wildfire smoke exposure appears to be more hazardous to humans than pollution from other sources.

show abstract

Section: Resultsmentioning

confidence: 99%

Metal toxin threat in wildland fires determined by geology and fire severity

Lopez,

Pacheco,

Fendorf

2023

Nat Commun

View full text Add to dashboard Cite

show abstract

“…Unlike oxidative conditions during combustion, reducing conditions during pyrolysis can produce various particle chemistries for redox-active metals. For example, during pyrolysis, Fe(III) can be reduced and converted to phases composed of Fe(II), such as magnetite or wüstite, and even to phases composed of Fe(0) 70 . The metal particle chemistry of wildfires is beginning to be revealed, with extensive research on coal combustion [71][72][73][74] , industrial waste incineration [75][76][77] , and structural fires (fires involving a building or other structure) 78,79 providing insight on the potential changes in metal speciation and particle size and chemistry resulting from wildfires.…”

Section: Inorganic Minerals In Ash and Soilmentioning

confidence: 99%

“…Metals are among the hundreds of different types of toxins present in airborne particulate matter during and after high-severity wildfires. Superparamagnetic magnetite and maghaemite have also been observed in spherical particles ranging from 0.1 to 2 µm in diameter following wildfires and, owing to the fine particle size, can be resuspended, with implications for direct toxicity and oxidative stress 70 . Additionally, fire-generated PAHs (particularly those with low molecular weight such as naphthalene and phenanthrene), Hg, and As can be emitted as gases and transported long distances [196][197][198] or redistributed on the soil surface within ash 199 .…”

Section: Smoke and Post-fire Dustmentioning

confidence: 99%

Molecular insights and impacts of wildfire-induced soil chemical changes

Lopez,

Avila,

VanderRoest

et al. 2024

Nat Rev Earth Environ

View full text Add to dashboard Cite

Wildfires act as important ecosystem controls and can benefit fire-adapted biomes by promoting habitat heterogeneity, seed germination and disease control. However, the frequency of highseverity fires and the extent of total burn area have increased since the 1970s, transforming both the organic and inorganic composition of soil. In this Review, we outline the molecular-scale transformations and biogeochemical interactions of soil organic matter (SOM) and metals induced by wildfires and explore their impacts on post-fire human health and ecosystem recovery. Wildfires enhance organic matter solubility and increase the number of nitrogen-containing SOM molecules by up to 32%. Additionally, wildfires can double the concentration of toxic polycyclic aromatic hydrocarbons (PAHs) in soil and induce the formation of toxic metal species such as As(III) and Cr(VI) through redox reactions. In post-fire environments, pyrogenic organic matter is susceptible to microbial degradation and can interact with soil minerals to influence metal redox cycling. Moreover, post-fire products such as karrikins and PAHs promote and inhibit revegetation, respectively, influencing ecosystem recovery. Improved techniques to monitor changes in the soil and the surrounding ecosystem are needed to better understand and mitigate the negative effects of wildfires. Key points• Wildfires increase water solubility and enrich nitrogen in soil organic matter while also generating toxic polycyclic aromatic hydrocarbons.• Wildfires can alter the oxidation state of metals, such as Cr, Hg and As, influencing their toxicity and mobility.• Laboratory measurements indicate that pyrogenic organic matter (PyOM) can be microbially degraded within weeks, suggesting that PyOM could have an important role in post-fire soil biogeochemical cycling.• The presence of growth-promoting organic molecules and growthinhibiting metal and organic species in post-fire soils can determine the success of revegetation efforts.• Future work should include organic and inorganic speciation measures to better estimate human and ecosystem impacts from wildfires.Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author selfarchiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

show abstract

“…Concentration ranges of additional metals enriched in ultrama c rocks, Ni, Fe, and Mn, were 2,294-3,489 mg/kg, 82.7-105.3 mg/g, and 1,910-2,547 mg/kg, respectively. A recent study found greater total Fe content in wildland ash (with variable geologic substrate) than structural ash, with median concentrations of 36.1 mg/g and 18.5 mg/g, respectively 51 .…”

mentioning

confidence: 95%

“…Total Cr content (946-1,643 mg/kg) was less than half the total Cr concentration measured in respective bulk compositions (up to 2-mm diameter). Chromium has been detected in nanoparticles of structural ash ranging from 90 to 270 nm in size 51 . Concentration ranges of additional metals enriched in ultrama c rocks, Ni, Fe, and Mn, were 2,294-3,489 mg/kg, 82.7-105.3 mg/g, and 1,910-2,547 mg/kg, respectively.…”

mentioning

confidence: 99%

Unforeseen Metal Toxin Produced in Particulates of Wildland Fires

Fendorf

Lopez

Lezama‐Pacheco

2023

Preprint

View full text Add to dashboard Cite

Accentuated by climate change, catastrophic wildfires are a growing, distributed global public health risk from inhalation of smoke and dust. An underrecognized health threat arises from altered naturally occurring metals originating in soils and plants. Here, we demonstrate that high temperatures during California wildfires catalyzed widespread transformation of chromium to its carcinogenic form in soil and ash, particularly in areas with metal-rich geologies. In wildfire ash, we observed dangerous levels of reactive hexavalent chromium in wind-dispersible particulates that persisted in surficial layers for up to a year post-fire. The geographic distribution of metal-rich soils and fire incidents illustrate the broad global threat of wildfire smoke- and dust-born metals to populations.

show abstract

Discovery and potential ramifications of reduced iron-bearing nanoparticles—magnetite, wüstite, and zero-valent iron—in wildland–urban interface fire ashes

Abstract: The increase in fires at the wildland-urban interface has raised concerns about the potential environmental impact of ash remaining after burning. Here, we examined the concentrations and speciation of iron-bearing...

Cited by 11 publications

References 85 publications

Metal toxin threat in wildland fires determined by geology and fire severity

Metal toxin threat in wildland fires determined by geology and fire severity

Molecular insights and impacts of wildfire-induced soil chemical changes

Unforeseen Metal Toxin Produced in Particulates of Wildland Fires

Contact Info

Product

Resources

About