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Cited by 108Fire effects on ecosystemsEnvironmental Toxicology and EcotoxicologyToxic Organic Pollutants Impact

Chemical composition of wildfire ash produced in contrasting ecosystems and its toxicity to Daphnia magna

Open access
Harper, Ashleigh R., Santin, Cristina, Doerr, Stefan H., Froyd, Cynthia A., Albini, Dania, Otero, Xose Luis, Viñas, Lucia, Pérez-Fernández, Begoña·2019·International Journal of Wildland Fire
DOI 10.1071/wf18200
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Abstract

It is well established in the world’s fire-prone regions that wildfires can considerably change the hydrological dynamics of freshwater catchments. Limited research, however, has focused on the potential impacts of wildfire ash toxicity on aquatic biota. Here, we assess the chemical composition and toxicity of ash generated from wildfires in six contrasting vegetation types distributed globally (UK grassland, Spanish pine forest, Spanish heathland, USA chaparral, Australian eucalypt forest and Canadian spruce forest). Acute (48 h) immobilisation tests were conducted on the extensively studied aquatic macroinvertebrate Daphnia magna, a sensitive indicator of aquatic contaminants. We found significant differences between the chemical composition and toxicity of these ash types. The UK and Spanish ash had no detectable toxicity to Daphnia magna, whereas the Australian eucalypt, USA chaparral and Canadian spruce ash all caused significant toxicity (immobilisation). The principal characteristics of the latter ash types were their high pH, and NO3−, Cl− and conductivity levels. Elevated water-soluble and total concentrations of metals (e.g. Mn, Fe, Zn, Pb, Cu and As) and total polycyclic aromatic hydrocarbons (PAHs) were not linked to toxicity.

Verified 2026-10-06 · 3 references not checked yet

AI snapshot

Written from the paper’s full text.

TL;DR

Wildfire ash from six contrasting ecosystems varied widely in chemistry; ash from Australian eucalypt, USA chaparral and Canadian spruce caused acute immobilisation of *Daphnia magna*, while UK grassland and Spanish pine/heathland ash did not. Toxicity was associated with high pH, conductivity, NO₃⁻ and Cl⁻, not with elevated metals or total PAHs.

Key findings

  • Acute 48-h *D. magna* immobilisation was significant for Australian eucalypt (AUS), USA chaparral (USA) and Canadian spruce (CAN) ash (P < 0.001 for all three), but not for Spanish heathland (URIA), Spanish pine (SPA) or UK grassland (UK) ash. AUS was most toxic, with 100% immobilisation at <25 g ash L⁻¹ within 24 h; 48-h EC₅₀ values were 9.5 g L⁻¹ (AUS), 20 g L⁻¹ (USA) and 26 g L⁻¹ (CAN).
  • Leachate pH ranged from 7.9 (UK) to 11.2 (USA), and electrical conductivity from 233 mS cm⁻¹ (SPA) to 3880 mS cm⁻¹ (AUS). PCA explained 79% of leachate variance (PC1 = 41%, PC2 = 23%, PC3 = 15%); the three toxic ash types were most closely correlated with high pH, EC, NO₃⁻, Cl⁻, Hg and SO₄²⁻.
  • Total Ca was the most abundant element (11,800–177,000 mg kg⁻¹); total As, Cd and Hg were lowest (0.46–9.67, 0.17–1.13 and 0–0.05 mg kg⁻¹ respectively). Water-soluble SO₄²⁻, Cl⁻ and Na were most abundant (1203–10,180, 228–1509 and 17–3893 mg kg⁻¹ respectively).
  • Σ16 EPA PAHs ranged from 1155 to 14,078 ng g⁻¹ ash, with the highest concentration in UK ash (14,078 ng g⁻¹). Elevated water-soluble and total metals (e.g. Mn, Fe, Zn, Pb, Cu, As) and total PAHs were not linked to toxicity; higher PAH concentrations were associated with reduced toxicity.

Methods

  • Six composite ash samples were collected after wildfires from UK grassland, Spanish pine forest, Spanish heathland, USA chaparral, Australian eucalypt forest and Canadian spruce forest; each was sieved through 1 mm before characterisation or bioassay.
  • Chemical characterisation measured total and water-soluble major and trace elements, pH, DOC and electrical conductivity, plus 35 PAHs by GC/MS; principal component analysis (PCA) was applied to water-soluble leachate data.
  • Acute 48-h immobilisation tests used *Daphnia magna* following OECD 202 except that pH was not adjusted to control levels; six ash concentrations (3.12, 6.25, 12.5, 25, 50, 75 g L⁻¹) plus controls were tested, with 150 daphnids per ash type. ANOVA with post-hoc Dunnett’s tests identified LOEC, EC₁₀ and EC₅₀ values.

Limitations

  • The paper states it is difficult to isolate primary causes of toxicity in complex, variable wildfire ash; possible indirect influences include pH, EC, Ca, DOC, Na and Mg, and physical particle size/distribution in unfiltered samples may have impaired feeding or locomotion.
  • The paper states PAHs were measured only in bulk ash, not the leachable fraction; synergistic, antagonistic or additive effects could not be ruled out, and longer-term sublethal PAH impacts were beyond the study scope. pH was not adjusted in the bioassays, though the authors justify this as closer to natural conditions and within OECD 202 guidance.
  • Evident from the text: toxicity was assessed with only one species (*D. magna*) and one acute endpoint (48-h immobilisation), with no chronic, field or community-level validation; ash samples were composites from single fire/ecosystem sources, limiting replication and generality.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1071/wf18200

Cites

55 of 58 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 112 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    UK and Spanish ash had no detectable toxicity to Daphnia magna.

    “The UK and Spanish ash had no detectable toxicity to Daphnia magna, whereas the Australian eucalypt, USA chaparral and Canadian spruce ash all caused significant toxicity (immobilisation).”
    Quote in the paperSubstantial claim
  • Findingown data

    Elevated water-soluble and total concentrations of metals (Mn, Fe, Zn, Pb, Cu and As) and total PAHs were not linked to toxicity.

    “Elevated water-soluble and total concentrations of metals (e.g.Mn, Fe, Zn, Pb, Cu and As) and total polycyclic aromatic hydrocarbons (PAHs) were not linked to toxicity.”
    Quote in the paperSubstantial claim
  • Findingown data

    The principal characteristics of the toxic ash types were high pH and high NO3−, Cl− and conductivity levels.

    “The principal characteristics of the latter ash types were their high pH, and NO 3 À , Cl À and conductivity levels.”
    Quote in the paperSubstantial claim
  • Findingown data

    The total elemental composition of the six ash types overall contained several potential contaminants, but in highly variable concentrations.

    “The total elemental composition of the six ash types overall contained several potential contaminants, but in highly variable concentrations (Supplementary material Table S1).”
    Quote in the paperNot a substantial claim
  • Findingown data

    Ca was the most abundant element in all ash samples, with a range of 11 800-177 000 mg kg−1.

    “The most abundant element in all samples was Ca (range 11 800-177 000 mg kg À1 )”
    Quote in the paperNot a substantial claim
  • May combine two claims. 54
  • Classified as probably not a substantial claim. 40

  • May combine two claims.

    Findingown data

    Australian eucalypt, USA chaparral and Canadian spruce ash caused significant toxicity (immobilisation) to Daphnia magna.

    “whereas the Australian eucalypt, USA chaparral and Canadian spruce ash all caused significant toxicity (immobilisation).”
    • Also stated in: § Acute toxicity test · plain
      “High levels of D. magna immobilisation were recorded at both 24-and 48-h exposure for three of the six ash types tested: AUS, USA and CAN (P , 0.001 for all three ash types)”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Al (range 1320-22 600 mg kg−1) and Fe (range 979-30 600 mg kg−1) were both present in high concentrations throughout the ash samples.

    “with Al (range 1320-22 600 mg kg À1 ) and Fe (range 979-30 600 mg kg À1 ) both present in high concentrations throughout.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    There are significant differences between the chemical composition and toxicity of the six wildfire ash types studied.

    “We found significant differences between the chemical composition and toxicity of these ash types.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    High pH and EC values were both characteristic features of the ash types producing immobilisation of Daphnia magna.

    “High pH and EC values were both characteristic features of the ash types producing immobilisation of Daphnia magna tested (see Acute toxicity test section).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    A characteristic component of the CAN sample was high levels of soluble Ca, despite the total concentration in dry ash being relatively similar to that of the AUS, SPA and USA ash.

    “A characteristic component of the CAN sample (identified by PCA, Fig. 1) was the high levels of soluble Ca, despite the total concentration in dry ash being relatively similar to that of the AUS, SPA and USA ash (Table 2).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Despite overall similarities in ash solubility, there are substantial variations among the ash types, making their chemical profiles notably different.

    “Despite the overall similarities in ash solubility in the ash leachates, there are also substantial variations among the ash types, making their chemical profiles notably different.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingreasoning

    pH within the bioassays themselves was notably less variable (7.31-9.08) than in the leachates, likely due to dilution and addition of culture medium.

    “pH within the bioassays themselves, however, was notably less variable (7.31-9.08),likely due to differences in dilution between leachates and the bioassay testing, and the addition of the culture medium in the latter.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Na (2-77%) and Hg (5-57%) solubility were highly variable and they are clearly the most soluble of the components analysed.

    “The levels of Na (2-77%) and Hg (5-57%) solubility were highly variable and they are clearly the most soluble of the components analysed.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The CAN sample had notably high levels of Ca (5864 mg kg−1) and SO4 (32 289 mg kg−1).

    “There were also notably high levels of, for example, Ca (5864 mg kg À1 ) and SO 4 2À (32 289 mg kg À1 ) in the CAN sample;”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The AUS sample had notably high levels of B (85 mg kg−1) and Na (3893 mg kg−1).

    “B (85 mg kg À1 ) and Na (3893 mg kg À1 ) in the AUS sample;”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Generally, the quantity of each ring type decreases sequentially with the number of rings (2 > 3 > 4 > 5 and 6), with the exception of the USA sample, which had a relatively similar quantity of three-, four-, five- and six-ring PAHs.

    “Generally, the quantity of each ring type decreases sequentially with the number of rings, 2 .3 .4 .5 and 6 with the exception of the USA sample, which had a relatively similar quantity of three-, four-, fiveand six-ring PAHs.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingreasoning

    The most abundant ions in all leachates were SO4, Cl and Na+, likely owing to them forming very soluble salts.

    “The most abundant ions in all leachates were SO 4 2À , Cl À and Na þ (Table 2), likely owing to them forming very soluble salts (i.e.sulfates or chlorides).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    PC1 is most strongly positively correlated with Mn, Fe, Zn, As, Pb and PO4 levels and most strongly negatively correlated with pH, EC, NO3, Cl, Hg and SO4.

    “PC1 is most strongly positively correlated with Mn, Fe, Zn, As, Pb and PO 4 3À levels and most strongly negatively correlated with pH, EC, NO 3 À , Cl À , Hg and SO 4 2À (Table 3 and Fig. 1).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The proportion of methylated and non-methylated PAHs was very similar in all samples, with approximately three times more non-methylated PAHs in each ash type except the USA ash, which contained over 15 times the amount of non-methylated PAHs.

    “The proportion of the methylated and non-methylated PAHs was very similar in all the samples with approximately three times more non-methylated PAHs in each ash type, except the USA ash, which contained over 15 times the amount of nonmethylated PAHs (Table 4).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The URIA sample had notably high levels of Cu (5158 mg kg−1) and As (329 mg kg−1).

    “and Cu (5158 mg kg À1 ) and As (329 mg kg À1 ) in the URIA sample (Table 2).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    pH and electrical conductivity in leachates varied notably across ash samples, with pH ranging from 7.9 in UK ash to 11.2 in USA ash.

    “pH and electrical conductivity (EC) measured in the leachates notably varied across ash samples, with pH levels ranging from moderately alkaline in the UK ash (7.9), to strongly alkaline in the USA ash (11.2).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    pH, EC, NO3, Cl, Hg and SO4 were most closely correlated with the three ash types producing significant immobilisation of D. magna, whereas Al, Cu, Ni, NH4, As, Fe, Mn, PO4, Pb and Cd were more closely correlated with the three non-toxic ash types.

    “A biplot of the standardised PC1 and PC2 values (Fig. 1) shows which components best characterised each ash type and pH, EC, NO 3 À , Cl À , Hg and SO 4 2À were most closely correlated with the three ash types producing significant immobilisation of D. magna, whereas Al, Cu, Ni, NH 4 þ , As, Fe, Mn, PO 4 3À , Pb, Cd were more closely correlated with the three non-toxic ash types (Fig. 1).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In the UK sample, PO4 (620 mg kg−1), Fe (4378 mg kg−1) and Mn (9292 mg kg−1) were notably high compared with the other ash types.

    “For example, in the UK sample, PO 4 3À (620 mg kg À1 ) and metals such as Fe (4378 mg kg À1 ) and Mn (9292 mg kg À1 ) were notably high in comparison with the other ash types.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Phenanthrene was the most common three-ring PAH, except in the UK sample where it was acenaphthylene.

    “Phenanthrene was the most common three-ring PAH, except in the UK sample where it was acenaphthylene.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The water-soluble (leachate) composition of the ash types was highly variable, with the most abundant components being SO4 (1203-10 180 mg kg−1), Cl (228-1509 mg kg−1) and Na (17-3893 mg kg−1).

    “The water-soluble (leachate) composition of the ash types was also highly variable (Table 2), with the most abundant components being SO 4 2À (range 1203-10 180 mg kg À1 ), Cl À (range 228-1509 mg kg À1 ) and Na (range 17-3893 mg kg À1 ).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    On average, the proportions of water-soluble Al, Pb, Mn, Fe and Zn were <1% total dry weight; As, Si, Ca, P, Ni, Cu and Cd were <5%; and Mg was <10%.

    “On average, the proportions of watersoluble Al, Pb, Mn, Fe, Zn were ,1% total dry weight; As, Si, Ca, P, Ni, Cu, Cd were ,5% and Mg was ,10%.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The total concentration of the 16 USEPA priority PAHs ranged from 1155 to 14 078 ng g−1 ash, with the highest total in the UK ash (12 336 ng g−1 ash).

    “The total concentration of these priority contaminants ranged from 1155 to 14 078 ng g À1 ash, the highest total being found in the UK ash originating from an upland grassland ecosystem in south Wales ( P 16 EPA PAHs: 12 336 ng g À1 ash) (Table 4).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Cd presented as a distinct principal component of the SPA ash with a comparatively high soluble concentration (7 mg kg−1) and as the only sample to register a solubility percentage greater than 1% (2.85%).

    “Despite this, Cd presented as a distinct principal component of the SPA ash with a comparatively high soluble concentration (7 mg kg À1 ) and as the only sample to register a solubility percentage greater than 1% (2.85%).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The URIA ash contained comparatively high concentrations of soluble Cu (5158 mg kg−1) and the carcinogen As (329 mg kg−1).

    “This ash contained comparatively high concentrations of soluble Cu (5158 mg kg À1 ) and the carcinogen As (329 mg kg À1 ).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The relationship between pH and immobilisation is very similar between the leachates and bioassays pH results, with higher pH values characteristic of the ash types producing immobilisation in D. magna.

    “Crucially, however, the relationship between pH and immobilisation is very similar between the leachates and bioassays pH results, with higher pH values characteristic of the ash types producing immobilisation in D. magna.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    The pH values in the bioassays themselves were notably lower and less variable than in the leachate results used during the PCA analysis and within a range thought acceptable for the survival of D. magna and similar cladoceran species.

    “The pH values in the bioassays themselves, however, were notably lower and less variable than in the leachate results used during the PCA analysis and within a range thought acceptable for the survival of D. magna and similar cladoceran species (OECD 2004) (Table 5 and 6).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites OECD 2004

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    The SPA ash has a relatively insoluble overall profile with notably high concentrations of Al, Fe, Zn, Cb, Pb and As in the dry ash but limited to no leaching of Al, Fe, Zn and Pb into the water-soluble extract.

    “The SPA ash has a relatively insoluble overall profile with notably high concentrations of the metals Al, Fe, Zn, Cb, Pb and the metalloid As in the dry ash (Supplementary material S1) but limited to no leaching of Al, Fe, Zn and Pb into the water-soluble extract (Table 2).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Although variations in combustion completeness could be related to PAH content here, the proportion of methylated PAHs in the UK ash is similar to that of the other samples tested.

    “Although variations in combustion completeness could be related to PAHs content here, the proportion of methylated PAHs in the UK ash is similar to that of the other samples tested (Table 4).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    The full range of PAH concentrations found here are within the range 1000-50 000 ng g−1 (Σ16 EPA PAHs) found by Santín et al. (2017) analysing PAHs in pine forest floor and wood under wildfire charring and slow pyrolysis.

    “The full range of PAH concentrations found here are within the range 1000-50 000 ng g 1 ( P 16 EPA PAHs) found by Santı ´n et al. (2017) analysing PAHs in pine forest floor and wood under wildfire charring and slow pyrolysis.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Santı ´n et al. 2017

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    Elevated water-soluble concentrations of metal and metalloid contaminants Mn, Fe, Zn, Pb, Cu and As did not produce any significant inhibition and tended to be characteristic of the non-toxic ash types.

    “Elevated water-soluble concentrations of metal and metalloid contaminants (Mn, Fe, Zn, Pb, Cu and As) did not produce any significant inhibition and tended to be characteristic of the non-toxic ash types.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The chemical characterisation of the six wildfire ash types shows an overall similar composition of elements, but significant variations in the concentration, reactivity and solubility of these elements.

    “The chemical characterisation of the six wildfire ash types shows an overall similar composition of elements, but significant variations in the concentration, reactivity and solubility of these elements.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    During wildland fires, combustion of fuels releases organic and inorganic components into the atmosphere and concentrates some of them into wildfire ash left on the ground.

    “During wildland fires, combustion of fuels releases a wide range of organic and inorganic components into the atmosphere but also concentrates some of them into wildfire ash left on the ground (Bodı ´et al. 2014).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Bodı ´et al. 2014

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Ash has begun to receive increasing recognition as a source of diffuse contamination in freshwater systems, and detrimental impacts on lake and stream biota including fish, amphibians, macroinvertebrates and algae have been observed.

    “Ash has also begun to receive increasing recognition as a source of diffuse contamination in freshwater systems and detrimental impacts on both lake and stream biota, including fish (e.g.Nunes et al. 2017;Oliveira-Filho et al. 2018;Gonino et al. 2019a), amphibians (Pilliod et al. 2003), macroinvertebrates (Brito et al. 2017) and algae (Campos et al. 2012) have all been observed.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Nunes et al. 2017 source

      Not checked in the free run.

    • cites Oliveira-Filho et al. 2018 source

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    • cites Gonino et al. 2019a

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Brito et al. (2017) found that all three Brazilian Cerrado ash types caused toxicity to Ceriodaphnia dubia, none affected Biomphalaria glabrata, and only one type was toxic for Danio rerio.

    “A similar study by Brito et al. (2017) tested toxicity over acute exposures (48 h) of three types of ash from the Brazilian Cerrado ecoregion on the planktonic crustacean Ceriodaphnia dubia, the fish Danio rerio and the mollusc Biomphalaria glabrata and found that all ash types caused toxicity to C. dubia, none affected B. glabrata and only one type was toxic for D. rerio.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Brito et al. 2017 source

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  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    PAHs and heavy metals present major biological concern owing to their carcinogenic potential, persistence within ecosystems and tendency to bio-accumulate.

    “Both present major biological concern owing to their carcinogenic potential, persistence within ecosystems and tendency to bio-accumulate (Smith et al. 2011;Chen et al. 2018).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Smith et al. 2011 source

      Not checked in the free run.

    • cites Chen et al. 2018 source

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  • Classified as probably not a substantial claim.

    Premisecitation

    Key areas receiving particular attention are the production and mobilisation of PAHs and heavy metals.

    “Key areas receiving particular attention as a result of concern about their environmental effects are the production and mobilisation of polycyclic aromatic hydrocarbons (PAHs) and heavy metals (e.g.Vila-Escale ´et al. 2007;Campos et al. 2012;Oliveira-Filho et al. 2018).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Vila-Escale ´et al. 2007 source

      Not checked in the free run.

    • cites Campos et al. 2012 source

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    • cites Oliveira-Filho et al. 2018 source

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  • Classified as probably not a substantial claim.

    Interpretationreasoning

    The leachate data were chosen for PCA because the leachate fraction is likely the most bioavailable fraction and therefore the most likely to have affected Daphnia over an acute exposure.

    “The leachates data were chosen for this analysis, as opposed to the total elements data, because this is likely the most bioavailable fraction and, therefore, the most likely to have affected the daphnia over an acute exposure.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Fresh wildfire ash typically consists of mineral materials and charred organic components, is noncohesive, has low density, and is not attached to soil, which facilitates its mobilisation and transport by post-fire water and wind erosion.

    “Fresh wildfire ash typically consists of mineral materials and charred organic components, is noncohesive, has a low density, and is not attached to the soil, which facilitates its mobilisation and transportation by post-fire water and wind erosion (Bodı ´et al. 2014;Abraham et al. 2017).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Bodı ´et al. 2014

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    • cites Abraham et al. 2017 source

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    These contaminants are thought to have complex impacts on water quality and their biological effects in aquatic systems have been observed to persist across long spatial and temporal scales.

    “These contaminants are thought to have complex impacts on water quality and the biological effects of these in aquatic systems have been observed to persist across long spatial and temporal scales (Earl and Blinn 2003;Costa et al. 2014).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Earl and Blinn 2003

      Not checked in the free run.

    • cites Costa et al. 2014 source

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Negative impacts of Brazilian sugarcane ash have been observed on several native fish species over 24-h acute exposures but not for two non-native fish species.

    “At higher trophic levels, negative impacts of Brazilian sugarcane ash have also been observed on several native fish species (Astyanax lacustris, Moenkhausia bonita and M. forestii) over 24-h acute exposures but not for two non-native fish species (Oreochromis niloticus and Poecilia reticulata) (Gonino et al. 2019b).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Gonino et al. 2019b

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  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    A wide range of ash concentrations was tested in an attempt to represent the potential variability of different natural scenarios.

    “Little is known to date on wildfire ash concentrations in water bodies; therefore, a wide range of ash concentrations was tested, trying to represent the potential variability of different natural scenarios.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Little is known about wildfire ash concentrations in water bodies, so the tested concentration range is needed to represent natural variability.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Daphnia magna is extensively used in ecological and toxicological studies as a sensitive indicator of the effects of contaminants on aquatic biota.

    “This species is extensively used in ecological and toxicological studies as a sensitive indicator of the effects of contaminants on aquatic biota (OECD 2004; USEPA 2016).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites OECD 2004

      Not checked in the free run.

    • cites USEPA 2016

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  • May combine two claims.

    Premisecitation

    Daphnia spp. are particularly relevant to freshwater lentic ecosystems and ideal for investigating contamination potential in downstream waterbodies.

    “Daphnia spp.are also particularly relevant to freshwater lentic ecosystems (lakes, reservoirs and ponds) and ideal for investigating contamination potential in downstream waterbodies (Robinson and Thorn 2005;Nikinmaa 2014).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Robinson and Thorn 2005

      Not checked in the free run.

    • cites Nikinmaa 2014

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The majority of general studies into the effects of wildfire on water quality have focused on runoff amounts and nutrient levels, and only more recently has increased research attention been given to pyrolytic substances, chemical elements and biological reactivity.

    “The majority of the general studies into the effects of wildfire on water quality have focused on runoff amounts and nutrient levels and only more recently has increased research attention been given to pyrolytic substances, chemical elements and biological reactivity (Shakesby and Doerr 2006;Campos et al. 2012;Silva et al. 2015).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Shakesby and Doerr 2006 source

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    • cites Campos et al. 2012 source

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    • cites Silva et al. 2015 source

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  • Classified as probably not a substantial claim.

    Premisecitation

    Release of soluble elements and particulate matter from eroded ash and underlying soil into aquatic systems following fires can cause increases in water turbidity, pH, organic matter, suspended sediment and conductivity and depletion of dissolved oxygen.

    “The release of soluble elements and particulate matter from eroded ash and underlying soil into aquatic systems following fires can cause increases in water turbidity, pH, organic matter, suspended sediment and conductivity and depletion of dissolved oxygen, among other effects (Smith et al. 2011;Tsai et al. 2017).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Smith et al. 2011 source

      Not checked in the free run.

    • cites Tsai et al. 2017 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Fire activity is projected to increase in many locations and ecotypes as a result of climate and societal changes.

    “Fire activity is projected to increase in many locations and ecotypes as a result of climate and societal changes, making the full understanding of their impacts crucial (Scholze et al. 2006;Chen et al. 2018).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Scholze et al. 2006 source

      Not checked in the free run.

    • cites Chen et al. 2018 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    The acute toxicity tests were conducted according to OECD 202 guidelines, with the exception of full pH adjustment.

    “The acute toxicity tests were conducted according to the OECD 202 (OECD 2004) guidelines, with the exception of full pH adjustment.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites OECD 2004

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Campos et al. (2012) and Silva et al. (2015) found no significant impact of eucalypt ash on Daphnia magna reproduction or immobilisation over chronic (21 day) and acute (48 h) exposures respectively.

    “Campos et al. (2012) and Silva et al. (2015), for example, found no significant impact of eucalypt ash on the planktonic crustacean Daphnia magna reproduction or immobilisation rates over a chronic (21 day) and acute (48 h) exposures respectively.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Campos et al. 2012 source

      Not checked in the free run.

    • cites Silva et al. 2015 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

    Interpretationcitation

    These studies demonstrate the variability and complexity of influencing factors in relation to the impacts of ash contamination on aquatic biota, highlighting the limited breadth of available research in this area.

    “These studies demonstrate the variability and complexity of influencing factors in relation to the impacts of ash contamination on aquatic biota, highlighting the limited breadth of available research in this area (Hallema et al. 2018).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Hallema et al. 2018 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Ash is not usually examined as a distinct part of post-fire sediment and few laboratory studies have characterised the composition of wildfire ash.

    “Ash is however not usually examined as a distinct part of the post-fire sediment and few laboratory studies have characterised the composition of wildfire ash (Bodı ´et al. 2014).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Bodı ´et al. 2014

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    B and Na are often found in high concentrations in ash leachates, particularly B in other eucalyptus ash tested.

    “These elements are often found in high concentrations in ash leachates (Jung et al. 2009;Pereira et al. 2011), particularly B in other eucalyptus ash tested (Freitas and Rocha 2011).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Jung et al. 2009 source

      Not checked in the free run.

    • cites Pereira et al. 2011 source

      Not checked in the free run.

    • cites Freitas and Rocha 2011

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The CAN ash tested here produced significant immobilisation of Daphnia magna over the 48-h exposure, potentially influenced by its high Ca concentration.

    “The CAN ash tested here produced significant immobilisation of Daphnia magna over the 48-h exposure also potentially influenced by its high Ca concentration.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Brito et al. (2017), assessing Brazilian Cerrado ash types, also found little qualitative difference in the overall composition of the different ash tested, but large variations in the concentration of chemical elements between sampling areas.

    “Brito et al. (2017), assessing Brazilian Cerrado ash types, also found there were little qualitative differences in the overall composition of the different ash tested, but large variations in the concentration of the chemical elements between sampling areas.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Brito et al. 2017 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Fire dynamics (e.g. burn temperature) and soil properties are important features in the composition of elements within ash.

    “Fire dynamics (e.g.burn temperature) and soil properties are also important features in the composition of elements within ash (Pitman 2006;Bodı ´et al. 2014;Chen et al. 2018).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Pitman 2006 source

      Not checked in the free run.

    • cites Bodı ´et al. 2014

      Not checked in the free run.

    • cites Chen et al. 2018 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    High Na+ levels in freshwater systems can present an issue for water purification processes as they cannot be removed using conventional methods.

    “High Na þ levels in freshwater systems can present an issue for water purification processes as they cannot be removed using conventional methods (Smith et al. 2011).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Smith et al. 2011 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Oxides and hydroxides of Ca, Mg, Si and P particularly tend to be abundant in wildfire ash, as found in the ash tested here.

    “In general, oxides and hydroxides of Ca, Mg, Si and P particularly tend to be abundant in wildfire ash (Pereira and U ´beda 2010;Silva et al. 2015) as found in the ash tested here (Supplementary material Table S1).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Pereira and U ´beda 2010

      Not checked in the free run.

    • cites Silva et al. 2015 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Stiernström et al. (2013) propose that Ca might be one of the key elements responsible for the ecotoxicity of ash eluates on the crustacean Nitocra spinipes, despite Ca not being classified as individually ecotoxic.

    “Stiernstro ¨m et al. (2013) even propose that Ca might be one of the key elements responsible for the ecotoxicity of ash eluates on the crustacean Nitocra spinipes, despite Ca not being classified as individually ecotoxic.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Stiernstro ¨m et al. 2013

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    This P-Ca interaction may influence algal and cyanobacterial growth (and thus eutrophication) by regulating P levels in freshwater systems.

    “This P-Ca interaction may influence algal and cyanobacterial growth (and thus, eutrophication) by regulating P levels in freshwater systems (Bladon et al. 2008;Blake et al. 2009).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Bladon et al. 2008 source

      Not checked in the free run.

    • cites Blake et al. 2009 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Ca is not normally considered hazardous, but can significantly influence the overall toxicity of ash eluates.

    “In the broader context, Ca is not normally considered hazardous, but can significantly influence the overall toxicity of ash eluates (e.g. its strong relationship with SO 4 2À leaching) (Mount et al. 1997;Tian et al. 2018).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Mount et al. 1997 source

      Not checked in the free run.

    • cites Tian et al. 2018 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationcitation

    It is unclear why the solubility of Ca is notably higher in the CAN ash, but it may be responsible for the reduced PO4 levels in the CAN leachate as P has a tendency to precipitate in the presence of Ca.

    “It is unclear why the solubility of Ca is notably higher in the CAN ash in comparison with the other ash types (Jung et al. 2009;Brito et al. 2017), but it may be responsible for the reduced PO 4 3À levels (1.2 mg kg À1 ) in the CAN leachate as P has a tendency to precipitate in the presence of Ca (Diaz et al. 1994).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Jung et al. 2009 source

      Not checked in the free run.

    • cites Brito et al. 2017 source

      Not checked in the free run.

    • cites Diaz et al. 1994 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    These results are similar to those found in other studies assessing post-fire runoff and ash leachates in a range of ecosystem types.

    “These results are similar to those found in other studies assessing post-fire runoff and ash leachates in a range of ecosystem types (Jung et al. 2009;Pereira et al. 2011) and in agreement with the general concentration trend of alkali (Na, K) .alkaline (Ca, Mg) .. heavy metals (Pb, Cd and Hg) found by Santı ´n et al. (2015) in eucalypt forest ash.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Jung et al. 2009 source

      Not checked in the free run.

    • cites Pereira et al. 2011 source

      Not checked in the free run.

    • cites Santı ´n et al. 2015

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Similar dry quantities of Cd were recorded by Brito et al. (2017) assessing Brazilian Cerrado ash types (0.1-0.3 mg kg−1) but Cd solubility was lower in these ash types (<0.01%).

    “Similar dry quantities of Cd were recorded by Brito et al. (2017) assessing Brazilian Cerrado ash types (0.1-0.3 mg kg À1 ) but Cd solubility was lower in these ash types (,0.01%).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Brito et al. 2017 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Many anthropogenic and natural conditions have been shown to increase nutrient concentrations to toxic levels.

    “Many anthropogenic (e.g. oil and gas production, irrigation methods and industrial and agricultural processes) and natural (e.g.sediment pore waters and burning) conditions have been shown to increase nutrient concentrations to toxic levels (e.g.Hoke et al. 1993;Ferreira et al. 2005;Mast and Clow 2008).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Hoke et al. 1993;Ferreira et al. 2005;Mast and Clow 2008

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The data available on PAH release following a fire are quite limited.

    “The data available on PAHs release following a fire, however, are quite limited (Vila-Escale ´et al. 2007;Kim et al. 2011;Campos et al. 2012;Rey-Salgueiro et al. 2018).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Vila-Escale ´et al. 2007 source

      Not checked in the free run.

    • cites Kim et al. 2011 source

      Not checked in the free run.

    • cites Campos et al. 2012 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The type of fuel and variations in combustion temperatures and oxygen availability are thought to strongly affect the concentration and type of PAHs in ash.

    “The type of fuel and variations in combustion temperatures and oxygen availability are thought to strongly affect the concentration and type of PAHs in ash (Enell et al. 2008;Rey-Salgueiro et al. 2018).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Enell et al. 2008 source

      Not checked in the free run.

    • cites Rey-Salgueiro et al. 2018 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The organic fraction of ash may also contain organic contaminants of biological concern.

    “The organic fraction of ash may also contain organic contaminants of biological concern (Vila-Escale ´et al. 2007;Chen et al. 2018).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Vila-Escale ´et al. 2007 source

      Not checked in the free run.

    • cites Chen et al. 2018 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    pH has an inconsistent relationship with toxicity, and results are often difficult to interpret.

    “pH has an inconsistent relationship with toxicity, and, often, results are difficult to interpret (Wilde et al. 2006;Silva et al. 2015).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Wilde et al. 2006;Silva et al. 2015

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Similar elevated soluble levels of Cu have been found in mixed eucalyptus ash (Cu 5100-6200 mg kg−1) by Santín et al. (2015).

    “Similar elevated soluble levels of Cu have, however, been found in mixed eucalyptus ash (Cu 5100-6200 mg kg À1 ) by Santı ´n et al. (2015).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Santı ´n et al. 2015

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Low pH values encourage the leaching of oxyanion-forming (As, B, Cr, Sb and V) and cation-forming elements (Ca), and neutral pH greatly reduces the leaching of amphoteric elements (Al, Cd, Cu, Pb and Zn).

    “Low pH values, for example, encourage the leaching of oxyanion-forming (As, B, Cr, Sb and V) and cation-forming elements (Ca), and neutral pH greatly reduces the leaching of amphoteric elements (e.g.Al, Cd, Cu, Pb and Zn) (Fedje et al. 2010).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Fedje et al. 2010 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Ash studies of beech and similar species were dominated by Naph and by Benzo(ghi)perylen, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Chry, Triphenylene and Phe but at lower concentrations.

    “Ash studies of beech and similar species (Bundt et al. 2001) were dominated by Naph and by Benzo(ghi)perylen, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Chry, Triphenylene and Phe but at lower concentrations.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Bundt et al. 2001 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Extreme values of pH and EC have a detrimental impact on zooplankton species.

    “It is well established that extreme values of pH and EC have a detrimental impact on zooplankton species (Mount et al. 1997;Franklin et al. 2000;Silva et al. 2015).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Mount et al. 1997 source

      Not checked in the free run.

    • cites Franklin et al. 2000 source

      Not checked in the free run.

    • cites Silva et al. 2015 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Scott and Crunkilton demonstrated that NO3- produces immobilisation of Daphnia magna at 462 mg L-1, with no observable effect concentration at 358 mg L-1.

    “Scott and Crunkilton (2000) demonstrated NO 3 À produces immobilisation of D. magna at 462 mg L À1 with no observable effect concentration at 358 mg L À1 .”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Scott and Crunkilton (2000)

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The influence of key nutrients on Daphnia magna immobilisation is perhaps less well established.

    “The influence of key nutrients on D. magna immobilisation is perhaps less well established (Smith et al. 2011)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Smith et al. 2011 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    PAH concentrations were only determined in bulk ash samples.

    “It has to be noted that PAHs concentrations were only determined in bulk ash samples.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationcitation

    It is likely that the high to very high PAH concentrations recorded in the ash studied here would be dramatically reduced if the leachable fraction of the samples were tested, as opposed to total concentrations, making the portion more accessible to interact with aquatic fauna lower.

    “It is likely the high to very high PAHs concentrations recorded in the ash studied here would be dramatically reduced if the leachable fraction of the samples were tested, as opposed to total concentrations, therefore making the portion more accessible to interact with aquatic fauna lower (Fris ˇta ´k et al. 2019).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Fris ˇta ´k et al. 2019

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationown data

    The results presented here justify concerns around the downstream contamination potential of ash in certain ecosystems on aquatic biota and highlight the need for a greater understanding of possible direct and indirect chemical causalities.

    “The results presented here justify the concerns around the downstream contamination potential of ash in certain ecosystems on aquatic biota and highlight the need for a greater understanding of possible direct and indirect chemical causalities.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The six ash types studied are representative of wildfire ash produced in contrasting ecosystems.

  • Classified as probably not a substantial claim.

    Premisecitation

    Earlier work has suggested that macroinvertebrate species such as Daphnia magna are less sensitive to contamination than lower trophic species.

    “Earlier work has suggested macroinvertebrate species such as D. magna are less sensitive to contamination than lower trophic species (Campos et al. 2012)”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Campos et al. 2012 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    A few notable studies have demonstrated no observable effect of ash toxicity on daphnid survival or reproduction rates over both acute 48 h and chronic 21 day exposures, but significant impacts have been observed on lower trophic species such as bacteria, algae and macrophytes.

    “A few notable studies have demonstrated this premise with no observable effect of ash toxicity on daphnid survival or reproduction rates over both acute (48 h) and chronic (21 day) exposures, but significant impacts have been observed on lower trophic species (bacteria, algae and macrophytes) (Campos et al. 2012;Silva et al. 2015).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Campos et al. 2012;Silva et al. 2015

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    It continues to prove difficult to identify specific causes of toxicity in aquatic biota using test substances as complex and variable as wildfire ash.

    “It continues to prove difficult to identify specific causes of toxicity in aquatic biota using test substances as complex and variable as wildfire ash.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    Combining the detailed chemical characterisation of the ash types with the ecotoxicology results helps to provide further insight into the composition and variations in ash produced in different ecosystem types and potential implications of wildfire ash contamination on the environment.

    “Combining the detailed chemical characterisation of the ash types with the ecotoxicology results helps to provide further insight into the composition and variations in ash produced in different ecosystem types and potential implications of wildfire ash contamination on the environment.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    The lack of relationship between high levels of PAHs and toxicity found here and in other studies raises questions about the bioavailability of PAHs in this context.

    “The lack of relationship between high levels of PAHs and toxicity found here and in other studies (Campos et al. 2012;Silva et al. 2015) raises questions about the bioavailability of PAHs in this context.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Campos et al. 2012;Silva et al. 2015

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

81 of 81

  • The paper relies on this without support.

    Little is known about wildfire ash concentrations in water bodies, so the tested concentration range is needed to represent natural variability.

    “Little is known to date on wildfire ash concentrations in water bodies; therefore, a wide range of ash concentrations was tested, trying to represent the potential variability of different natural scenarios.”

  • The paper relies on this without support.

    The composite ash samples collected from each ecosystem type are representative of wildfire ash produced in those ecosystems.

    “Six composite ash samples were collected after wildland fires, before any rainfall, in each of the selected ecosystems types (Table 1): Australian eucalypt forest (AUS), USA chaparral (USA), Canadian spruce forest (CAN), Spanish heathland”

  • The paper relies on this without support.

    Not adjusting pH in the bioassays does not cause significant changes to the test substances or create interactions that invalidate the toxicity results.

    “It is crucially important that pH adjustment does not cause significant changes to the test substances and owing to the complex and varying compositions and reactivity of wildfire ash, potential interactions are unclear.”

  • The paper relies on this without support.

    No other research has been conducted on the PAH composition of wildfire ash originating from comparable grassland ecosystems.

    “It is unclear why this is the case as no other research has been conducted on the PAHs composition of wildfire ash originating from comparable grassland ecosystems.”

  • The paper relies on this without support.

    Ions such as Cl- and NO3- are required at minimum levels to support aquatic life.

    “as ions such as Cl À and NO 3 À are required at minimum levels to support aquatic life.”

  • The paper relies on this without support.

    The toxicity of individual ions in single-substance tests can be used to judge their contribution in complex ash leachates.

    “This suggests despite the correlations between NO 3 À and Cl À with the toxic ash types found here, the relatively low quantities of these components alone are not likely capable of causing the observed toxicity (Table 2).”

  • The paper relies on this without support.

    The six ash types studied are representative of wildfire ash produced in contrasting ecosystems.

    “The chemical characterisation of the six wildfire ash types shows an overall similar composition of elements, but significant variations in the concentration, reactivity and solubility of these elements.”
7 of 7

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Sulfate range excludes the Canadian ash value

    Minor

    The stated maximum water-soluble sulfate concentration is 10 180 mg kg À1, but the same section reports 32 289 mg kg À1 for the Canadian ash.

  • Conclusion calls all elements low-solubility despite stated exceptions

    Minor

    The conclusion says solubility was low for all elements and ash types, but the results identify Na and Hg as exceptions, with solubilities reaching 77% and 57%.

  • Two different UK priority-PAH totals are reported

    Minor

    The UK total for the 16 priority PAHs is reported as 12 336 ng g À1 here, but as 14 078 ng g À1 elsewhere in the results and in Table 4.

  • Complete immobilisation is claimed below 25 g L À1

    Minor

    Table 5 shows 75% immobilisation at 12.5 g L À1 and first shows 100% at 25 g L À1, not at a concentration less than 25 g L À1.

4 of 4

Cites

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Authors
Harper, A. R., Santin, C., Doerr, S. H., Froyd, C. A., Albini, D., Otero, X. L., Viñas, L., & Pérez-Fernández, B.
Affiliations
  • Swansea University (GB)
  • ADepartment of Geography, Swansea University, Singleton Park, Swansea, SA2 8PP, UK.
  • CDepartment of Edaphology and Agricultural Chemistry, Faculty of Biology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
  • Instituto Español de Oceanografía (ES)
Corresponding author
Harper, Ashleigh R.
ORCID
Venue
International Journal of Wildland Fire
Publisher
CSIRO Publishing
Published
2019-08-06
Volume
28
Issue
10
Pages
726-737
ISSN
  • 1049-8001 (ISSN-L)
  • 1448-5516
DOI
10.1071/wf18200
OpenAlex
W2965875207
Cited by
108
References
58
Citations by year
2026: 15 · 2025: 24 · 2024: 20 · 2023: 10 · 2022: 22 · 2021: 8 · 2020: 8 · 2019: 1
FWCI
5.02
Type
journal article
Language
en
Open access
Licence
Locations
  • International Journal of Wildland Fire (publishedVersion, cc-by-nc-nd)
  • LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) (publishedVersion, other-oa)
  • DIGITAL.CSIC (Spanish National Research Council (CSIC)) (submittedVersion)
  • Hispana (submittedVersion, cc-by-nc-nd)
  • Repositorio institucional da Universidade de Santiago de Compostela (University of Santiago de Compostela) (submittedVersion, cc-by-nc-nd)
Funders
  • Leverhulme Trust (RF‐2016‐456\2, 663830)
  • European Commission (663830)
  • Swansea University (663830)
  • Natural Environment Research Council (NE/R011125/1)
Topics
  • Physical Sciences › Environmental Science › Global and Planetary Change › Fire effects on ecosystems
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Environmental Toxicology and Ecotoxicology
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Toxic Organic Pollutants Impact
Keywords
wildfire ash, Daphnia magna, aquatic toxicity, ash composition, eucalypt forest, chaparral, spruce forest, pine forest, heathland, grassland, polycyclic aromatic hydrocarbons, heavy metals, water-soluble metals, vegetation types

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-06.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-06.

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