Thallium Speciation and Extractability in a Thallium- and Arsenic-Rich Soil Developed from Mineralized Carbonate Rock

• DOI: 10.1021/acs.est.5b00629
• Publication Date: 2015-04-17T15:44:10Z
• Authors: Andreas Voegelin; Numa Pfenninger; Julia Petrikis; Juraj Majzlan; Michael Plötze; Anna-Caterina Senn; Stefan Mangold; Ralph Steininger; Jörg Göttlicher
• Keywords: Illite; Jarosite; Topsoil; Aqua regia; Thallium

We investigated the speciation and extractability of Tl in soil developed from mineralized carbonate rock. Total concentrations topsoil (0–20 cm) 100–1000 mg/kg are observed most affected area, subsoil up to 6000 horizons containing weathered ore fragments. Using synchrotron-based microfocused X-ray fluorescence spectrometry (μ-XRF) absorption spectroscopy (μ-XAS) at L3-edge, partly Tl(I)-substituted jarosite avicennite (Tl2O3) were identified as Tl-bearing secondary minerals formed by weathering a Tl–As–Fe-sulfide mineralization hosted rock which developed. Further evidence was found for sequestration Tl(III) into Mn-oxides uptake Tl(I) illite. Quantification fractions Tl(III), Tl(I)-jarosite Tl(I)-illite bulk samples based on XAS indicated that illite dominant retention mechanism materials. Oxidative Tl(III)uptake less relevant, probably because loadings exceeded capacity this mechanism. The 10 mM CaCl2-extracts increased with increasing contents decreasing pH, but did not exhibit drastic variations function speciation. With respect contaminated soils, study provides first direct spectroscopic indicates need further studies sorption clay its impact solubility soils.