Thallium contamination of soils/vegetation as affected by sphalerite weathering: a model rhizospheric experiment.

Abstract

The environmental stability of Tl-rich sphalerite in two contrasting soils was studied. Rhizospheric conditions were simulated to assess the risk associated with sulfide microparticles entering agricultural (top)soils. The data presented here clearly demonstrate a significant effect of 500 μM citric acid, a model rhizospheric solution, on ZnS alteration followed by enhanced Tl and Zn release. The relative ZnS mass loss after 28 days of citrate incubation reached 0.05 and 0.03 wt.% in Cambisol and Leptosol samples respectively, and was up to 4 times higher, compared to H2O treatments. Incongruent (i.e., substantially increased) mobilization of Tl from ZnS was observed during the incubation time. Generally higher (long-term) stability of ZnS with lower Tl release is predicted for soils enriched in carbonates. Furthermore, the important role of silicates (mainly illite) in the stabilization of mobilized Tl, linked with structural (inter)layer Tl-K exchange, is suggested. Thallium was highly bioavailable, as indicated by its uptake by white mustard; maximum Tl amounts were detected in biomass grown on the acidic Cambisol. Despite the fact that sulfides are thought as relatively stable phases in soil environments, enhanced sulfide dissolution and Tl/trace element release (and bioaccumulation) can be assumed in rhizosphere systems.

DOI: 10.1016/j.jhazmat.2014.09.018

Cite this paper

@article{Vank2015ThalliumCO, title={Thallium contamination of soils/vegetation as affected by sphalerite weathering: a model rhizospheric experiment.}, author={Ale{\vs} Vaněk and Zuzana Gr{\"{o}sslov{\'a} and Martin Mihaljevi{\vc} and Vojtěch Ettler and Vladislav Chrastn{\'y} and Michael Kom{\'a}rek and V{\'a}clav Tejneck{\'y} and Ondřej Dr{\'a}bek and V{\'i}t Pen{\'i}{\vz}ek and Ivana Galu{\vs}kov{\'a} and Barbora Vaně{\vc}kov{\'a} and Lenka Pavlů and Christopher Ash}, journal={Journal of hazardous materials}, year={2015}, volume={283}, pages={148-56} }