title: Valorization of a treated soil via amendments: fractionation and oral bioaccessibility of Cu, Ni, Pb, and Zn.
abstract: The present study aims to transform a treated soil (TS) into a more desirable resource by modifying physico-chemical properties via amendments while reducing toxic metals' mobility and oral bioaccessibility. A hydrocarbon-contaminated soil submitted to treatment (TS) but still containing elevated concentrations of Cu, Ni, Pb, and Zn has been amended with compost, sand, and Al2(SO4)3 to render it usable for horticulture. Characterization and sequential extraction were performed for TS and four amended mixtures (AM1-4). P and K availability and metal bioaccessibility were investigated in TS and AM2. Amendment improved soil properties for all mixtures and yielded a usable product (AM2 20 % TS, 49 % compost, 30 % sand, 1 % Al2(SO4)3) satisfying regulatory requirements except for Pb content. In particular, AM2 had improved organic matter (OM) and cation exchange capacity (CEC), highly increased P and K availability, and reduced total metal concentrations. Furthermore, amendment decreased metal mobile fraction likely to be plant-available (in mg kg(-1), assumed as soluble/exchangeable + carbonates fractions). For AM2, estimated Pb bioavailability decreased from 1.50 × 10(3) mg kg(-1) (TS) to 238 mg kg(-1) (52.4 % (TS) to 34.2 %). Bioaccessible concentrations of Cu, Ni, and Zn (mg kg(-1)) were lower in AM2 than in TS, but there was no significant decrease for Pb. The results suggest that amendment improved soil by modifying its chemistry, resulting in lower metal mobile fraction (in %, for Cu and Zn) and bioaccessibility (in %, for Cu only). Amending soils having residual metal contamination can be an efficient valorization method, indicating potential for reducing treatment cost and environmental burden by rendering disposal/additional treatment unnecessary. Further studies including plant bioavailability are recommended to confirm results.
authors.affiliation: Department of Civil, Geological and Mining Engineering, École Polytechnique de Montréal, H3C 3A7, Montréal, Québec, Canada. gerald.zagury@polymtl.ca.
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Zagury
authors.affiliation: Department of Civil, Geological and Mining Engineering, École Polytechnique de Montréal, H3C 3A7, Montréal, Québec, Canada.|Northex Environnement Inc., J0L 1C0, Contrecoeur, Québec, Canada.
authors.forename: Jhony A
authors.initials: JA
authors.lastname: Rincon Bello
authors.affiliation: Department of Civil, Geological and Mining Engineering, École Polytechnique de Montréal, H3C 3A7, Montréal, Québec, Canada.
authors.forename: Mert
authors.initials: M
authors.lastname: Guney
mesh_terms: D001682:Biological Availability; D003300:Copper / Q000032:analysis; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D004784:Environmental Monitoring; D004787:Environmental Pollution / Q000706:statistics & numerical data*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D006801:Humans; D007854:Lead / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis*; D009532:Nickel / Q000032:analysis; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D015032:Zinc / Q000032:analysis*
chemical_list: D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D007854:Lead; D003300:Copper; D009532:Nickel; D015032:Zinc
keywords: Metal mobility; Metals; Oral bioaccessibility; Sequential extractions; Soil contamination; Soil valorization