In situ stabilization of arsenic and lead in contaminated soil using iron‐rich water treatment residuals

Rathnayake, Sewwandi; Schwab, A. P.

doi:10.1002/jeq2.20347

Cited by 3 publications

(5 citation statements)

References 86 publications

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“…Bioaccessibility of As associated with Fe ferrihydrite depends on the bond type between iron oxide and As. The sorbed As species have relatively higher bioaccessibility compared to co‐precipitated As with ferrihydrite (Jeong et al., 2017; Kim et al., 2014; Meunier et al., 2010; Rathnayake & Schwab, 2022).…”

Section: Resultsmentioning

confidence: 99%

Organic amendments temporarily change arsenic speciation and bioaccessibility in a lead and arsenic co‐contaminated urban soil

Attanayake,

Hettiarachchi,

Dissanayake

et al. 2024

J of Env Quality

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Organic amendments often reduce the bioaccessibility of soil lead (Pb) but not that of soil arsenic (As). The effect of Pb on As bioaccessibility is rarely studied in co‐contaminated soils. In a field study, we assessed the effect of mushroom compost, leaf compost, noncomposted biosolids, and composted biosolids amendments on As speciation in a co‐contaminated (As and Pb) soil at 7, 349, and 642 days after amending soils and the change of As speciation during an in vitro bioaccessibility extraction (gastric solution, pH 2.5) using bulk X‐ray absorption near‐edge structure spectroscopy. Soil was contaminated by coal combustion and other diffuse sources and had low As bioaccessibility (7%–12%). Unamended soil had As(III) sorbed onto pyrite (As(III)‐pyrite; ∼60%) and As(V) adsorbed onto Fe oxy(hydr)oxides (As(V)‐Fh; ∼40%). In amended soils, except in composted biosolids‐amended soils, at 7 days, As(V)‐Fh decreased to 15%–26% and redistributed into As(III)‐Fh and/or As(III)‐pyrite. This transformation was most pronounced in mushroom compost amended soil resulting in a significant (46%) increase of As bioaccessibility compared to the unamended soil. Composted biosolids‐amended soils had relatively stable As(V)‐Fh. Lead arsenate formed during the in vitro extraction in amended soils, except in composted biosolids‐amended soils. Arsenic speciation and bioaccessibility were similar in 349‐ and 642‐day in all the amended and unamended soils. Reduction of As(V)‐Fh to As(III) forms in the short term in three of the amended soils showed the potential to increase As bioaccessibility. The formation of stable lead arsenate during the in vitro extraction would counteract the short‐term increase of As bioaccessibility in those amended soils.

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Section: Resultsmentioning

confidence: 99%

Organic amendments temporarily change arsenic speciation and bioaccessibility in a lead and arsenic co‐contaminated urban soil

Attanayake,

Hettiarachchi,

Dissanayake

et al. 2024

J of Env Quality

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“…Similarly, using the SBRC gastric phase, Silvetti et al [61] showed that treatment of two soils (2428 and 860 mg As kg -1 ) impacted by mining and chromated copper arsenate with an Al-WTRs (13.9% Al) marginally reduced As IVBA (TERs of 0.80-0.81). In contrast, although Rathnayake and Schwab [58] showed significant reductions in As IVBA (USEPA Method 1340) when Fe-WTRs containing 12% Fe were applied to a smelter-impacted soil (7520 mg As kg -1 and 66,400 mg Pb kg -1 ) at Fe:As molar ratios of 2:1, 5:1, and 10:1 (TERs of 0.27, 0.06, and 0.04), a significant reduction in simultaneous Pb and As IVBA was only observed at the highest application rate (TER of 0.79). The ineffectiveness of Fe-WTRs in immobilizing Pb compared to As may be due to the fact that Pb adsorbed by Fe oxides is readily solubilized in gastric solution.…”

Section: Immobilization Efficacy Assessed Using Ivbamentioning

confidence: 94%

“…High Pb TERs have been observed following the use of Al/ Fe-rich WTR amendments, with Pb TERs ranging from 0.93 to 0.99 in Silvetti et al [61], 0.93 to 0.94 in Mele et al [60], and 0.79 to 0.96 in Rathnayake and Schwab [58]. However, Rathnayake and Schwab [58••] reported a TER of 0.26 when using Fe-rich WTRs (Fe:Pb = 10:1) and phosphate (P:Pb = 5:1) simultaneously (using USEPA Method 1340) compared to Fe-rich WTRs alone (TER of 0.96), phosphate alone (TER of 0.50), or sequential application of phosphate followed by Fe-rich WTRs (TER of 0.50).…”

Section: Immobilization Efficacy Assessed Using Ivbamentioning

confidence: 99%

“…Varied immobilization performance has also been observed for metal oxides when applied to As co-contaminated soils. Rathnayake and Schwab [58] applied goethite and ferrihydrite to contaminated soil at Fe:As molar ratios of 2:1, 5:1, and 10:1, which resulted in a decrease in As IVBA (USEPA Method 1340; TERs of 0.54-0.91), showing increasing immobilization efficacy with increasing application rate. However, the performance of Fe oxides was less effective at the same Fe:As molar ratio when compared to Fe-WTRs (TERs of 0.04-0.27).…”

Section: Immobilization Efficacy Assessed Using Ivbamentioning

confidence: 99%

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Opportunities and Challenges Associated with Bioavailability-Based Remediation Strategies for Lead-Contaminated Soil with Arsenic as a Co-Contaminant—A Critical Review

Kastury

Karna

et al. 2023

Curr Pollution Rep

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Purpose of Review The ubiquity of soil contamination by lead (Pb) and arsenic (As) has prompted the development of numerous techniques for its remediation. For human health exposure assessment, oral bioavailability-based methods are the most suitable to assess the efficacy of these treatment strategies, including in vivo relative bioavailability (systemic absorption relative to a toxicity reference) and in vitro bioaccessibility (dissolution in simulated gastrointestinal solutions). This paper provides a critical review of opportunities and challenges associated with the immobilization of Pb and As in contaminated soil. Recent Findings This review identified that the major inorganic and organic amendments used to reduce Pb and As exposure include phosphate, industrial by-products, metal oxides, organic matter, biochar, and treatment with iron sulphate to promote the formation of plumbojarosite in soil. In addition to RBA and IVBA assessment, investigating changes in Pb/As speciation in untreated vs treated soil can provide additional confirmation of treatment efficacy. The results of this review showed that immobilization efficacy may vary depending on amendment type, Pb, and As speciation in soil and the approach used for its assessment. Summary Reducing childhood exposure to Pb and As is a significant challenge, given the variety of contamination sources and treatment strategies. A lines-of-evidence approach using standardized methodologies is recommended for the assessment of immobilization efficacy to ensure exposure and risk reduction Graphical Abstract Bioavailability-based remediation strategies. Popular soil amendments to reduce Pb exposure include phosphate, industrial by-products, metal oxides, organic matter, and biochar; however, these may increase As exposure. The plumbojarosite formation technique has been recently developed to mitigate Pb and As exposure simultaneously. Multiple lines-of-evidence approach is recommended to assess treatment efficacy

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“…Thus, the effective restoration of As-polluted soils requires sound knowledge of As interaction with soil components. Several researchers have examined the potential of WTRs in restoring As-polluted soils (Nielsen et al, 2011 ; Rathnayake & Schwab, 2022 ; Sarkar et al, 2007a , 2007b ). They found that utilization of Fe WTRs at a rate of 3% successfully stabilized heavily polluted soils with heavy metals including arsenic (Garau et al, 2014 ).…”

Section: Introductionmentioning

confidence: 99%

Potential use of nanoparticles produced from byproducts of drinking water industry in stabilizing arsenic in alkaline-contaminated soils

Moharem

Hamadeen

Mesalem

et al. 2023

Environ Geochem Health

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The stabilization of heavy metals in soils is considered a cost-effective and environmentally sustainable remediation approach. In the current study, the applicability of water treatment residual nanoparticles (nWTRs) with the particle size ranged from 45 to 96 nm was evaluated for its efficacy in reducing arsenic mobility in clayey and sandy contaminated alkaline soils. Sorption isotherms, kinetics, speciation and fractionation studies were performed. Sorption equilibrium and kinetics studies revealed that As sorption by nWTRs-amended soils followed Langmuir and second-order/power function models. The maximum As sorption capacity (qmax) of Langmuir increased up to 21- and 15-folds in clayey and sandy soils, respectively, as a result of nWTRs application at 0.3% rate. A drastic reduction in non-residual (NORS) As fraction from 80.2 and 51.49% to 11.25 and 14.42% for clayey and sandy soils, respectively, at 0.3% nWTRs application rate was observed, whereas residual (RS) As fraction in both studied soils strongly increased following nWTRs application. The decline in percentage of As mobile form (arsenious acid) in both soils after nWTRs application indicated the strong effect of nWTRs on As immobilization in contaminated soils. Furthermore, Fourier transmission infrared spectroscopy analysis suggested reaction mechanisms between As and the surfaces of amorphous Fe and Al oxides of nWTRs through OH groups. This study highlights the effective management approach of using nWTRs as soil amendment to stabilize As in contaminated alkaline soils.

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In situ stabilization of arsenic and lead in contaminated soil using iron‐rich water treatment residuals

Cited by 3 publications

References 86 publications

Organic amendments temporarily change arsenic speciation and bioaccessibility in a lead and arsenic co‐contaminated urban soil

Organic amendments temporarily change arsenic speciation and bioaccessibility in a lead and arsenic co‐contaminated urban soil

Opportunities and Challenges Associated with Bioavailability-Based Remediation Strategies for Lead-Contaminated Soil with Arsenic as a Co-Contaminant—A Critical Review

Potential use of nanoparticles produced from byproducts of drinking water industry in stabilizing arsenic in alkaline-contaminated soils

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