Wildfires on Cr-rich Ferralsols can cause freshwater Cr(VI) pollution: A pilot study in New Caledonia

Thery, Gaël; Juillot, Farid; Meyer, Michaël; Quiniou, Thomas; David, Magali; Jourand, Philippe; Ducousso, Marc; Fritsch, Emmanuel

doi:10.1016/j.apgeochem.2022.105513

Cited by 4 publications

(3 citation statements)

References 96 publications

(120 reference statements)

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“…Fire-generated Cr(VI) weakly adsorbs to soil minerals in alkaline conditions and is easily displaced by other oxyanions, including phosphate and sulfate. These changes could potentially make Cr(VI) more susceptible to leaching into surface waters, threatening aquatic habitats and drinking water sources 136 . Measurements of the amount of aqueous Cr(VI) formed after laboratory heating have been used to estimate the potential post-fire risk of freshwater Cr(VI) pollution in Cr-rich environments in New Caledonia 136 .…”

Section: Redox Cycling Of Metal Toxinsmentioning

confidence: 99%

“…These changes could potentially make Cr(VI) more susceptible to leaching into surface waters, threatening aquatic habitats and drinking water sources 136 . Measurements of the amount of aqueous Cr(VI) formed after laboratory heating have been used to estimate the potential post-fire risk of freshwater Cr(VI) pollution in Cr-rich environments in New Caledonia 136 . However, further field measurements of aqueous Cr(VI) following wildfires and precipitation events are needed to verify whether such leaching occurs.…”

Section: Redox Cycling Of Metal Toxinsmentioning

confidence: 99%

“…Erosion-mediated dilution could mitigate the toxicity of AEA in some scenarios. Fires also increase the concentration of PAHs and metals in the soil, which can be transported to nearby water bodies 36,38,136 , but the transport and fate of such compounds are highly complex and must be further analysed to accurately predict fire-driven contaminant risks.…”

Section: Water Qualitymentioning

confidence: 99%

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Molecular insights and impacts of wildfire-induced soil chemical changes

Lopez,

Avila,

VanderRoest

et al. 2024

Nat Rev Earth Environ

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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.

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Section: Redox Cycling Of Metal Toxinsmentioning

confidence: 99%

Section: Redox Cycling Of Metal Toxinsmentioning

confidence: 99%