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Cited by 87Per- and polyfluoroalkyl substances researchPharmaceutical and Antibiotic Environmental ImpactsPesticide and Herbicide Environmental Studies

Perfluoroalkyl acids on suspended particles: Significant transport pathways in surface runoff, surface waters, and subsurface soils

Open access
Borthakur, Annesh, Wang, Meng, He, Meng, Ascencio, Katia, Blotevogel, Jens, Adamson, David T., Mahendra, Shaily, Mohanty, Sanjay K.·2021·Journal of Hazardous Materials
DOI 10.1016/j.jhazmat.2021.126159
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Abstract

Eroded particles from the source zone could transport a high concentration of perfluoroalkyl acids (PFAAs) to sediments and water bodies. Yet, the contribution of suspended particles has not been systematically reviewed. Analyzing reported studies, we quantitatively demonstrate that suspended particles in surface water can contain significantly higher concentrations of PFAAs than the sediment below, indicating the source of suspended particles are not the sediment but particles eroded and carried from the source zone upstream. The affinity of PFAAs to particles depends on the particle composition, including organic carbon fraction and iron or aluminum oxide content. In soils, most PFAAs are retained within the top 5 m below the ground surface. The distribution of PFAAs in the subsurface varies based on site properties and local weather conditions. The depth corresponding to the maximum concentration of PFAA in soil decreases with an increase in soil organic carbon or rainfall amount received in the catchment areas. We attribute a greater accumulation of PFAAs near the upper layer of the subsurface to an increase in the accumulation of particles eroded from source zones upstream receiving heavy rainfall. Precursor transformation in the aerobic zone is significantly higher than in the anaerobic zone, thereby making the aerobic subsurface zone serve as a long-term source of groundwater pollution. Collectively, these results suggest that suspended particles, often an overlooked vector for PFAAs, can be a dominant pathway for the transport of PFAAs in environments.

Verified 2026-10-06 · 1 reference not checked yet

AI snapshot

Written from the paper’s full text.

TL;DR

This review synthesizes reported data to argue that suspended particles are an overlooked but potentially dominant transport vector for perfluoroalkyl acids (PFAAs) in surface runoff, surface waters, and subsurface soils. It finds that particle-associated PFAAs can greatly exceed bed-sediment concentrations and that most PFAAs are retained in shallow subsurface, with organic carbon, mineral oxides, rainfall, and aerobic precursor transformation influencing distribution.

Key findings

  • Suspended particles in surface waters often contain 1–3 orders of magnitude higher PFAA concentrations than bed sediments, indicating eroded source-zone particles rather than sediment resuspension; PFSAs are enriched more than PFCAs, with Koc values 5.1–5.8 times greater for PFSAs than PFCAs in suspended sediments versus 1.7 times in sediments.
  • Most PFAAs are retained within the top 5 m below ground surface; the depth of maximum PFAA concentration decreases with increasing soil organic carbon content or annual precipitation, which the authors attribute to erosion and deposition of impacted particles and to oxic-zone precursor transformation.
  • Aerobic precursor biotransformation is an order of magnitude faster than anaerobic transformation (p < 0.02), while no significant difference (p > 0.05) was found among half-lives of non-ionic, anionic, and zwitterionic precursors.
  • PFAA sorption to particles and soils is associated with organic carbon, iron oxide, and aluminum oxide content; PFOS adsorption is higher than PFOA adsorption for the same mineralogical properties.

Methods

  • Literature search in Web of Science in July 2020 using keyword combinations of “PFAS” with “properties,” “soil,” and “water”; 697 articles were found, 249 were selected after title and abstract screening, and the final synthesis analyzed 35 studies.
  • Quantitative comparisons included PFAA concentrations in suspended particles versus bed sediments, normalized vertical subsurface profiles, correlations with soil organic carbon and annual precipitation, and correlations of PFOA/PFOS sorption with soil mineralogy.
  • Subsets included 20 studies on PFAA precursor biotransformation, 11 studies on PFOA/PFOS adsorption affinity, 6 studies on mineralogy-related sorption, and 5 studies on vertical PFOA/PFOS distribution within 4 m of the ground surface.

Limitations

  • Stated: soil conclusions apply to hotspots because soil PFAA data came from hotspot studies, and background concentrations are not often reported.
  • Stated: limited data were available beyond 5 m depth, groundwater table locations were often unreported, hydraulic conductivity data were not provided to confirm the precipitation/erosion hypothesis, and mineral correlations were weak potentially due to interactive effects among minerals.
  • Evident: the review relies on heterogeneous published datasets with small subsets for some analyses (e.g., only five studies reported organic carbon content, and six studies were used for mineralogy correlations), which limits causal inference and generalizability; the paper also notes that source apportionment based on particle-associated PFAS requires further environmental forensic work not explored in detail.

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

Integrity signals

Registry

Crossref · 10.1016/j.jhazmat.2021.126159

Cites

103 of 104 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 69 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Suspended particles in surface water can contain significantly higher concentrations of PFAAs than the sediment below.

    “Analyzing reported studies, we quantitatively demonstrate that suspended particles in surface water can contain significantly higher concentrations of PFAAs than the sediment below, indicating the source of suspended particles are not the sediment but particles eroded and carried from the source zone upstream.”
    • Also stated in: § 3.1. Surface water · plain
      “Our analysis reveals that suspended particles in surface water bodies often contain a disproportionally higher concentration of PFAAs than the sediment below the water columns.”
    Quote in the paperSubstantial claim
  • Findingreasoning

    Suspended particles are enriched with perfluoroalkane sulfonic acids (PFSAs) to a greater extent than perfluoroalkyl carboxylic acids (PFCAs).

    “The suspended particles are enriched with perfluoroalkane sulfonic acids (PFSAs) to a greater extent than perfluoroalkyl carboxylic acids (PFCAs) (Fig. 2), possibly due to the higher affinity of PFSAs to suspended sediments than that of PFCAs.”
    Quote in the paperSubstantial claim
  • Findingreasoning

    The depth corresponding to PFAA concentration maxima decreased with an increase in annual precipitation received at the sites assessed.

    “However, our analysis reveals that the depth corresponding to PFAA concentration maxima decreased with an increase in annual precipitation received at the sites assessed (Fig. 5b).”
    • Also stated in: § Abstract · plain
      “The depth corresponding to the maximum concentration of PFAA in soil decreases with an increase in soil organic carbon or rainfall amount received in the catchment areas.”
    Quote in the paperSubstantial claim
  • Findingreasoning

    PFAAs are accumulated near the surface in areas receiving high annual precipitation.

    “In other words, PFAAs are accumulated near the surface in areas receiving high annual precipitation.”
    Quote in the paperSubstantial claim
  • Findingown data

    The concentration of most PFAAs decreased steadily with increases in depth surveyed.

    “Our analysis reveals that the concentration of most PFAAs decreased steadily with increases in depth surveyed (Fig. 3).”
    Quote in the paperSubstantial claim
  • May combine two claims. 26
  • Classified as probably not a substantial claim. 12

  • May combine two claims.

    Findingreasoning

    Biotransformation depends on functional groups on the precursors: hydroxyl groups are highly susceptible to enzymatic transformation whereas the urethane group is least susceptible.

    “The analysis also reveals that biotransformation depends on functional groups on the precursors: hydroxyl groups are highly susceptible to enzymatic transformation whereas the urethane group is least susceptible, possibly due to the unavailability of urethane transforming enzymes in most soil microorganisms.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given

    PFAA concentration in subsurface soil is typically high within the top 5 m below ground surface and decreases rapidly thereafter.

    “The concentration of PFAAs in subsurface soil is typically high within the top 5 m below ground surface, but the concentration decreased thereafter rapidly”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    The correlation between PFAA sorption and the dominant compositional properties is weak, potentially because of the interactive effect between these minerals.

    “However, it should be noted that the correlation is weak, potentially because of the interactive effect between these minerals.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    Suspended particles could transport a significant amount of PFAAs in surface water and recontaminate sediments.

    “Nevertheless, our result indicates that suspended particles could transport a significant amount of PFAAs in surface water and recontaminate sediments.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductnone given

    Limited data were available beyond 5 m depth, and groundwater table locations in most sites were not reported.

    “There was also limited data available beyond 5 m depth, and the groundwater table locations in most sites were not reported.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Aqueous PFAAs in infiltrating water have been shown to adsorb on pore walls, infiltrate into the soil matrix, or accumulate at air-water interfaces.

    “Aqueous PFAAs in infiltrating water have been shown to adsorb on pore walls, infiltrate into the soil matrix, or accumulate at air-water interfaces (Brusseau, 2019;Lyu et al., 2018;Meng et al., 2014).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Brusseau, 2019 source

      Not checked in the free run.

    • cites Lyu et al., 2018 source

      Not checked in the free run.

    • cites Meng et al., 2014

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Variability in data increases with decrease in Kd of the compound, as desorption of PFAAs increases with decrease in Kd.

    “This is supported by the fact that the variability in data increases with the decrease in K d of the compound, as the desorption of PFAAs increase with the decrease in K d of the compound (Milinovic et al., 2015).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Milinovic et al., 2015 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    PFOS has a high affinity and low desorption coefficient, so its concentration profile in the subsurface exhibited the lowest variability.

    “Because PFOS has a high affinity and low desorption coefficient, its concentration profile in the subsurface exhibited the lowest variability.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    A previous study observed an increase in PFAA sorption onto the soil with an increase in organic carbon content and decreasing clay content.

    “A previous study (Anderson et al., 2019) observed an increase in PFAA sorption onto the soil with an increase in organic carbon content and decreasing clay content.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Anderson et al., 2019 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Areas receiving high rainfall amounts can deposit more impacted particles downstream, most of which are filtered out in topsoil.

    “Consequently, areas receiving high rainfall amounts can deposit more impacted particles downstream, most of which are filtered out in topsoil (Tondera et al., 2013).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Tondera et al., 2013

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Particle-associated PFAA transport could lower the effectiveness of remediation of impacted sediments and delay cleanup.

    “This could lower the effectiveness of remediation of impacted sediments in a surface water body and delay the cleanup effort of sediment.”
    Quote in the paperSubstantial claim

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

    Interpretationcitation

    Other soil properties such as hydraulic conductivity, soil chemical heterogeneity, air-water interface, and protein, iron oxide, and manganese oxide content may also contribute to variable PFAA transport in subsurface soil.

    “It should be noted that other soil properties such as hydraulic conductivity, soil chemical heterogeneity, air-water interface, and protein, iron oxide, and manganese oxide content may also contribute to variable PFAA transport in subsurface soil (Gellrich et al., 2012;Guelfo et al., 2020;Hoisaeter et al., 2019;Longstaffe et al., 2012;Lyu et al., 2018;Ololade et al., 2016).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Gellrich et al., 2012 source

      Not checked in the free run.

    • cites Guelfo et al., 2020

      Not checked in the free run.

    • cites Hoisaeter et al., 2019 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Accumulation of PFAA and PFAA-containing particles in subsurface soil and transformation of PFAA precursors in aerobic conditions could make subsurface soils serve as a secondary source for PFAAs to groundwater.

    “However, accumulation of PFAA and PFAAcontaining particles in subsurface soil and transformation of PFAA precursors in aerobic conditions could make subsurface soils serve as a secondary source for PFAAs to groundwater (Weber et al., 2017).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Weber et al., 2017 source

      Not checked in the free run.

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

    Interpretationreasoning

    These factors are expected to affect the soil depth corresponding to maximum PFAA concentration.

    “Thus, these factors are expected to affect the soil depth corresponding to maximum PFAA concentration.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    PFAAs may migrate down the subsurface due to leaching and redistribution, and sorbed PFAS can desorb and leach leading to downward migration.

    “First, PFAAs may migrate down the subsurface due to leaching and redistribution of PFAAs in the subsurface.Sorbed PFAS compounds can desorb and leach from the soil, which can lead to their downward migration through the subsurface (Gellrich et al., 2012).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Gellrich et al., 2012 source

      Not checked in the free run.

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

    Premisecitation

    The same previous study observed an increase in PFAA transport with the degree of flushing.

    “Moreover, they also observed an increase in PFAA transport with the degree of flushing.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Anderson et al., 2019 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based).

    Interpretationreasoning

    The concentration maxima of PFAS compounds should move to deeper layers in subsurface soil with an increased precipitation rate.

    “Thus, the concentration maxima of PFAS compounds should move to deeper layers in subsurface soil with an increased precipitation rate.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    An increase in precipitation in an area could increase the amount of water flushed through subsurface soil, which could increase the desorption of PFAS from subsurface soil to groundwater.

    “Generally, it is expected that an increase in precipitation in an area could increase the amount of water flushed through subsurface soil, which could increase the desorption of PFAS from subsurface soil to groundwater (Anderson et al., 2019).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Anderson et al., 2019 source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    The subsurface can adsorb aqueous PFAAs and filter PFAA-impacted particles from infiltrating water, and the impacted region can subsequently release the PFAAs over longer periods.

    “The subsurface can also adsorb aqueous PFAAs and filter PFAAimpacted particles from infiltrating water, and the impacted region can subsequently release the PFAAs over longer periods.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Suspended particles can be removed from pore water by diffusion, straining or sedimentation.

    “Suspended particles can be removed from the pore water by diffusion, straining or sedimentation (Bradford et al., 2002;Flury and Qiu, 2008).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Bradford et al., 2002

      Not checked in the free run.

    • cites Flury and Qiu, 2008

      Not checked in the free run.

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

    Premisecitation

    PFAS and their precursors can be removed by adsorption to soil minerals, air-water interfaces, and microbial biomass or roots, translocated into plants, and degraded or transformed by soil microorganisms.

    “Briefly, PFAS and their precursors can be removed by adsorption to soil minerals, air-water interfaces, and microbial biomass or roots, translocated into plants, and degraded or transformed by soil microorganisms.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Sharifan et al., 2021 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Adsorption of cationic and zwitterionic precursors to soil minerals could reduce their bioavailability, consequently the likelihood of them being transformed to PFAAs.

    “Adsorption of cationic and zwitterionic precursors to soil minerals could reduce their bioavailability, consequently the likelihood of them being transformed to PFAAs (Mejia-Avendano et al., 2020).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Mejia-Avendano et al., 2020

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationreasoning

    Another possibility for high accumulation of PFAAs near the surface compared to deeper soil in wet climates is that deeper soils in wetter climates remain submerged most of the time, developing anoxic conditions, while near-surface soil could drain and become oxic.

    “Another possibility of the high accumulation of PFAAs near the surface compared to deeper soil in wet climates is that deeper soils in wetter climates remain submerged most of the time, thereby developing anoxic conditions.In contrast, near-surface soil could drain and become oxic.”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    Perturbation of air-water interfaces during dry-wet and freeze-thaw cycles could release PFAA attached to air-water interfaces.

    “Perturbation of air-water interfaces during dry-wet and freeze-thaw cycles could release PFAA attached to air-water interfaces.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    The air-water interface is dynamic and collapses during rewetting.

    “However, the air-water interface is dynamic and collapses during rewetting.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Subsurface soils naturally experience dry-wet and freeze-thaw cycles, which can accelerate the mobilization of particles and particle-associated pollutants.

    “Subsurface soils naturally experience dry-wet and freeze-thaw cycles, which can accelerate the mobilization of particles and particleassociated pollutants (Mohanty et al., 2014).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Mohanty et al., 2014

      Not checked in the free run.

  • May combine two claims.

    Interpretationnone given

    Surface runoff carries PFAAs and eroded particles impacted with PFAAs from source zones to surface waters.

    “Surface runoff carries PFAAs and eroded particles impacted with PFAAs from the source zones to surface waters.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given

    Cationic and zwitterionic PFAS have positive charges, whereas most natural soil particles have a net negative charge.

    “Cationic and zwitterionic PFAS have positive charges, whereas most natural soil particles have a net negative charge.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationnone given

    Impacted runoff can infiltrate into subsurface soil, where PFAAs can adsorb on soil or impacted particles can be deposited in topsoil, which can serve as a long-term source for groundwater pollution.

    “Impacted runoff can infiltrate into the subsurface soil where PFAAs can adsorb on soil or impacted particles can be deposited in topsoil, which can serve as a long-term source for groundwater pollution.”
    Quote in the paperSubstantial claim

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

    Study design and conductnone given

    Hydraulic conductivity data was not provided in the assessed studies to confirm the hypothesis that soil types determine the amount of runoff that infiltrates into the ground.

    “However, hydraulic conductivity data was not provided in the assessed studies to confirm this hypothesis.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Limited studies have examined the transport of cationic and zwitterionic PFAS, and none of these studies considered particle-mediated transport.

    “However, limited studies have examined the transport of cationic and zwitterionic PFAS (Barzen--Hanson et al., 2017;Mejia-Avendano et al., 2020;Nickerson et al., 2021;Xiao et al., 2019), and none of these studies considered particle-mediated transport.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Barzen--Hanson et al., 2017 source

      Not checked in the free run.

    • cites Mejia-Avendano et al., 2020

      Not checked in the free run.

    • cites Nickerson et al., 2021 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    The biotransformation rate of precursors at deeper depths will be lower in wetter climates than drier climates.

    “Thus, the biotransformation rate of precursors at the deeper depths will be lower in wetter climates than drier climates.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    The air-water interface can retain significant amounts of PFAAs and has been found to be the major retention mechanism of PFAAs in the subsurface.

    “The air-water interface can retain significant amounts of PFAAs and has been found to be the major retention mechanism of PFAAs in the subsurface (Brusseau, 2018).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Brusseau, 2018 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Most studies filter or centrifuge samples before analysis, and these steps remove particles and could potentially lower the measured PFAA concentration in water samples.

    “Most studies filter or centrifuge samples before analysis (Qiu et al., 2010;Zhou et al., 2013).These steps remove particles and could potentially lower the measured PFAA concentration in the water samples.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Qiu et al., 2010

      Not checked in the free run.

    • cites Zhou et al., 2013 source

      Not checked in the free run.

34 of 34

  • The authors state this as an assumption.

    Advection of dissolved PFAAs is the dominant mechanism of transport in surface waters and subsurface.

    “Advection of dissolved PFAAs is currently assumed to be the dominant mechanism of transport in surface waters and subsurface (Dauchy et al., 2019b(Dauchy et al., , 2019a;;Xiao et al., 2012), whereas sorption to soil or sediment is considered the primary retention mechanism.”

  • The paper relies on this without support.

    Sorption to soil or sediment is the primary retention mechanism for PFAAs.

    “Advection of dissolved PFAAs is currently assumed to be the dominant mechanism of transport in surface waters and subsurface (Dauchy et al., 2019b(Dauchy et al., , 2019a;;Xiao et al., 2012), whereas sorption to soil or sediment is considered the primary retention mechanism.”

  • The paper relies on this without support.

    The subsurface zone acts as a natural filter to remove particles in surface runoff and adsorb pollutants.

    “Impacted surface runoff passes through the subsurface zone before reaching groundwater, so the subsurface zone acts as a natural filter to remove particles in surface runoff and adsorb pollutants.”

  • The paper relies on this without support.

    Soil types, not only precipitation amount, determine the amount of runoff that infiltrates into the ground.

    “It should be noted that the soil types, not only the precipitation amount, determine the amount of runoff that infiltrates into the ground.”

  • The paper relies on this without support.

    The role of suspended particles on PFAA transport is relatively unexplored.

    “The role of suspended particles on PFAA transport is relatively unexplored, although their role in enhancing the transport of other organic chemicals such as polycyclic aromatic hydrocarbons (Guo et al., 2007), chlorinated solvents (Tanabe and Tatsukawa, 1983), and heavy metals (Zhang, 1999) has been well established.”

  • The paper relies on this without support.

    The relevance of suspended particles on PFAA distribution in the environment has not been critically reviewed.

    “However, the relevance of suspended particles on PFAA distribution in the environment has not been critically reviewed, although the fate and transport of aqueous PFAA in the environment have been reviewed extensively (Ahmed et al., 2020;Ahrens and Bundschuh, 2014;Armitage et al., 2009;Banzhaf et al., 2017;Brusseau et al., 2020;Lam et al., 2017;Nadal and Domingo, 2014;Prevedouros et al., 2006;Shar”

  • The paper relies on this without support.

    Risk assessment studies often overlook the transport of PFAAs in association with suspended particles eroded from source zones.

    “Risk assessment studies often overlook the transport of PFAAs in association with suspended particles eroded from the source zones.”
    “suspended particles, which are often ignored in previous assessment studies”
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?

  • The fate and transport of sediment-bound PFAS in rivers, lakes, estuaries, and open waters are governed by different hydrological processes, making watershed-level sediment monitoring critical.

    “While there are several other studies on PFAS occurrence in sediment, the fate and transport of sedimentbound PFAS in rivers, lakes, estuaries, and open waters are governed by different hydrological processes, 29,30 rendering it critical to perform watershed level sediment monitoring”

    From Per- and Polyfluoroalkyl Substances in Surface Water and Fluvial Sediments of a Rural Gulf Coast Watershed: A Year-long Spatiotemporal Assessment (2026) · cites this paper as [30]

    The Introduction and §3.1 (page unavailable) describe runoff, flow velocity, deposition, and turbulence as processes affecting particle-bound PFAA transport in surface waters. The paper does not distinguish hydrological processes across rivers, lakes, estuaries, and open waters. The watershed-level monitoring recommendation follows the citations in the citing sentence and appears to be the citing authors’ conclusion, not a separate claim attributed to this source. (LLM, conf=0.82)

    Experimental — accuracy not yet measured

  • Biotransformation of retained PFAS precursors into less sorptive terminal PFASs is an expected phenomenon in soil media.

    “Biotransformation of the retained PFAS precursors into less sorptive terminal PFASs (e.g., SC-PFCAs, PFOA, and PFOS), which depends on oxic/anoxic conditions at the accumulation depth, is also an expected phenomenon in soil media.”

    From Occurrence, Concentration, and Distribution of 35 PFASs and Their Precursors Retained in 20 Stormwater Biofilters (2024) · cites this paper as [49]

    Section 3.2 (Subsurface soil; page unavailable) says that strongly retained cationic and zwitterionic precursors may transform into less sorptive anionic PFAAs, and reports faster precursor transformation under aerobic than anaerobic conditions. It presents the soil-mobility consequence as a possibility, not an expected outcome for retained PFAS precursors generally, and does not identify SC-PFCAs, PFOA, and PFOS as the products of that transformation. (LLM, conf=0.82)

    Experimental — accuracy not yet measured

  • PFSA are reported to adsorb more readily to riverine solids than PFCA.

    “Generally, PFSA are reported to adsorb more readily to riverine solids than PFCA (Borthakur et al., 2021; Wang et al., 2023).”

    From Occurrence of emerging and persistent organic pollutants in the rivers Cam, Ouse and Thames, UK (2025) · cites this paper as Borthakur et al., 2021

  • Some studied pollutants, especially PFAS, have high sorptive properties, and thus the extent of water pollution by these substances cannot be inferred from analysis of water samples only.

    “Furthermore, some of the studied pollutants, especially PFAS, have been reported to possess high sorptive properties (Borthakur et al., 2021; Wang et al., 2023; Folorunsho et al., 2024), and thus the extent of water pollution by these substances cannot be inferred from the analysis of water samples only.”

    From Occurrence of emerging and persistent organic pollutants in the rivers Cam, Ouse and Thames, UK (2025) · cites this paper as Borthakur et al., 2021

  • PFASs released from source zones during weathering and drainage events are delivered either via suspended solids in runoffs to surface waters or via leaching to groundwater.

    “PFASs released from source zones during weathering and drainage events are delivered either via suspended solids in runoffs to surface waters or via leaching to groundwater.11−13”

    From Sources and Pathways of PFAS Occurrence in Water Sources: Relative Contribution of Land-Applied Biosolids in an Agricultural Dominated Watershed (2025) · cites this paper as [12]

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.

  • Figure 5b is described as showing a different outcome

    Minor

    Section 4.2 cites Fig. 5b as evidence that surface PFAA concentrations increase with precipitation. The figure caption instead identifies its outcome as the subsurface depth of maximum PFAA concentration, not surface concentration.

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. Borthakur, 2021, Dataset for the review: Perfluoroalkyl acids on suspended particles: Significant transport pathways in surface runoff, surface waters, and subsurface soils., figshare. Collection.

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Authors
Borthakur, A., Wang, M., He, M., Ascencio, K., Blotevogel, J., Adamson, D. T., Mahendra, S., & Mohanty, S. K.
Affiliations
  • University of California, Los Angeles (US)
  • University of Pittsburgh (US)
  • Colorado State University (US)
  • GSI Environmental (United States) (US)
Corresponding author
Mohanty, Sanjay K.
ORCID
Venue
Journal of Hazardous Materials
Publisher
Elsevier BV
Published
2021-09
Volume
417
Pages
126159
ISSN
0304-3894 (ISSN-L)
DOI
10.1016/j.jhazmat.2021.126159
OpenAlex
W3162149283
Cited by
87
References
103
Citations by year
2026: 13 · 2025: 20 · 2024: 18 · 2023: 14 · 2022: 16 · 2021: 6
FWCI
1.00
Type
journal article
Language
en
Open access
Licence
Locations
  • Journal of Hazardous Materials (publishedVersion, cc-by)
  • PubMed (publishedVersion)
Topics
  • Physical Sciences › Environmental Science › Environmental Chemistry › Per- and polyfluoroalkyl substances research
  • Physical Sciences › Environmental Science › Pollution › Pharmaceutical and Antibiotic Environmental Impacts
  • Physical Sciences › Environmental Science › Pollution › Pesticide and Herbicide Environmental Studies
Keywords
perfluoroalkyl acids, suspended particulate matter, surface runoff, surface water contamination, soil organic carbon, iron and aluminum oxides, particle erosion, source zone, groundwater contamination, precursor transformation, rainfall effects
MeSH terms
Carbon, Environmental Monitoring, Fluorocarbons, Soil, Water Pollutants, Chemical, Groundwater

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.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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