title: A sequential extraction procedure to evaluate the mobilization behavior of rare earth elements in soils and tailings materials.
abstract: A novel sequential extraction method for evaluation of the mobilization behavior of rare earth elements in soils and mine tailings materials is presented. The sequence consists of the following four steps: 0.05 mol L(-1) calcium nitrate (easily soluble and ion exchange fraction), 0.1 mol L(-1) citric acid (fraction mobilized by complexation and carbonate bound), 0.05 mol L(-1) hydroxylamine hydrochloride (pH = 2) (reducible fraction), 1.4 mol L(-1) nitric acid (acid soluble fraction). The procedure was optimized with a certified soil material and a mine tailings material and was applied to eight samples of a soil profile. The different results obtained by using either the developed method or the widespread used BCR-Method for comparison are discussed. There were clear advantages using the newly created sequential extraction procedure in getting more detailed information about the bioavailable fraction and a fraction addressing REE phosphates.
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Analytical Chemistry, Permoserstrasse 15, 04318 Leipzig, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Mittermüller
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Analytical Chemistry, Permoserstrasse 15, 04318 Leipzig, Germany.
authors.forename: Jessica
authors.initials: J
authors.lastname: Saatz
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Analytical Chemistry, Permoserstrasse 15, 04318 Leipzig, Germany. Electronic address: birgit.daus@ufz.de.
authors.forename: Birgit
authors.initials: B
authors.lastname: Daus
mesh_terms: D017610:Calcium Compounds / Q000737:chemistry; D005591:Chemical Fractionation; D019343:Citric Acid / Q000737:chemistry; D019811:Hydroxylamine / Q000737:chemistry; D007220:Industrial Waste; D008674:Metals, Rare Earth / Q000737:chemistry*; D008906:Mining; D009566:Nitrates / Q000737:chemistry; D017942:Nitric Acid / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D017610:Calcium Compounds; D007220:Industrial Waste; D008674:Metals, Rare Earth; D009566:Nitrates; D010710:Phosphates; D012989:Soil Pollutants; D019343:Citric Acid; D019811:Hydroxylamine; D017942:Nitric Acid; C059948:calcium nitrate
keywords: BCR sequential extraction procedure; Bioavailability; Fractionation; ICP-MS; Leachability; REE