Vanadium bioavailability in soils amended with blast furnace slag

Abstract

Blast furnace (BF) slags are commonly applied as soil amendments and in road fill material. In Sweden they are also naturally high in vanadium. The aim of this study was to assess the vanadium bioavailability in BF slags when applied to soil. Two soils were amended with up to 29 % BF slag (containing 800 mg V kg -1 ) and equilibrated outdoors for 10 months before conducting a barley shoot growth assay. Additional soil samples were spiked with dissolved vanadate(V) for which assays were conducted two weeks (freshly spiked) and 10 months (aged) after spiking. The BF slag vanadium was dominated by vanadium(III) as shown by V K-edge XANES spectroscopy. In contrast, results obtained by HPLC-ICP-MS showed that vanadium(V), the most toxic vanadium species, was predominant in the soil solution. Barley shoot growth was not affected by the BF slag additions. This was likely due to limited dissolution of vanadium from the BF slag, preventing an increase of dissolved vanadium above toxic thresholds. The difference in vanadium bioavailability among treatments was explained by the vanadium concentration in the soil solution. It was concluded that the vanadium in BF slag is sparingly available. These findings should be of importance in environmental risk assessment.

Vanadium sorption by mineral soils: Development of a predictive model

“…b The vanadium oxidation state was calculated from the K-edge energy position according to Larsson et al (2015a) c The sample without V addition, which was included as a standard in the fit.…”

“…Vanadate(V) is considered the most toxic vanadium species (Martin and Kaplan, 1998;Larsson et al 2013). In three Swedish soils it was found that the soil appears to be dominated by vanadium(IV) bound in primary minerals (Larsson et al 2015a;Larsson et al 2015b); this V has probably a low bioavailability. However, when vanadium is added to soils (either as vanadium(IV) or vanadium(V) salts), it tends to accumulate as vanadate(V) sorbed to iron and aluminium hydrous oxides, except in acid organic soils, in which vanadyl(IV) complexed to organic matter will predominate (Larsson et al 2015a, Larsson et al 2015b).…”

“…The values of the surface complexation constants, as well as results from competition experiments, show that vanadate(V) is bound even more strongly than phosphate and arsenate on Fe hydrous oxides (Rietra, 2001;Brinza et al 2008;Wällstedt et al 2010). The role of Al hydrous oxides for vanadate(V) sorption is less well known, although results from vanadium K-edge XANES experiments show that they contribute significantly to adsorption (Burke et al 2012;Larsson et al 2015a).…”

“…The spectra for Pustnäs A and Säby A have been reported elsewhere(Larsson et al 2015b), but here we give further details on linear combination fitting results. Procedures for collecting spectra of standards (V oxides, vanadate(V) adsorbed to ferrihydrite, vanadyl(IV) complexed to organic matter, etc) are detailed inLarsson et al (2015a). Beamline 4-3 was equipped with a Si[111] double crystal monochromator, and it operated at 3.0 GeV with a current of 97-100 mA.…”

Metal Transport near a Tailings Facility in the Alberta Oil Sands

“…While WHAM7 does not model these elements, literature indicated that they too are likely sequestered by organic molecules (Bowell, 1994;Kautenburger et al, 2017;Larsson et al, 2015;Lu et al, 1998;Maji et al, 2008;Wang et al, 2015;Wichard et al, 2009;Xu et al, 1991). Arsenic and Mo typically prefer oxyhydroxides, such as goethite and hematite, however, in competitive environments with humic substances, they preferentially sorb to organics (Bowell, 1994;Wichard et al, 2009;Xu et al, 1991).…”