title: Column leaching of chromium and nickel from a contaminated soil using EDTA and citric acid.
abstract: This study investigates the column leaching of a soil contaminated mainly with Cr and Ni by using two chelants: citric acid (biodegradable) and EDTA (non-biodegradable) followed with water rinse. The chelants lead to Cr and Ni leaching, in addition to major elements (Ca, Fe, Mg, Al, Mn and Zn) showing the dissolution of soil mineral constituents. EDTA leaches more major elements and Ni than citric acid related to the respective stability of metal-chelant complexes; citric acid leaches more Cr than EDTA, certainly because of a substitution reaction with Cr(VI). In the case of alternating chelant/water applications, leaching occurs during the chelant applications, but also during water applications. In the case of chelant/water applications followed by continuous water application, both Cr and Ni leach over time. This increased mobility could be due to the residual chelant present in soil as well as to the dissolution/mobilization of mineral or organic soil fractions.
authors.affiliation: Université de Limoges, Groupe de Recherche Eau Sol Environnement (GRESE), 123 Avenue Albert Thomas, 87060 Limoges, France.
authors.forename: Liliane
authors.initials: L
authors.lastname: Jean-Soro
authors.forename: François
authors.initials: F
authors.lastname: Bordas
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Bollinger
mesh_terms: D002857:Chromium / Q000032:analysis / Q000737:chemistry*; D019343:Citric Acid / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D009532:Nickel / Q000032:analysis / Q000737:chemistry*; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D002857:Chromium; D019343:Citric Acid; D009532:Nickel; D004492:Edetic Acid