The aqueous chemistry of polonium (Po) in environmental and anthropogenic processes

Rahul Ram; James Vaughan; Barbara Etschmann; Joël Brugger

doi:10.1016/j.jhazmat.2019.06.002

The aqueous chemistry of polonium (Po) in environmental and anthropogenic processes

J Hazard Mater. 2019 Dec 15:380:120725. doi: 10.1016/j.jhazmat.2019.06.002. Epub 2019 Jun 29.

Authors

Rahul Ram¹, James Vaughan², Barbara Etschmann³, Joël Brugger⁴

Affiliations

¹ School of Earth, Atmosphere and Environment, Building 28, 9 Rainforest Walk, Monash University, Clayton, VIC 3800, Australia. Electronic address: rahul.ram@monash.edu.
² School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia.
³ School of Earth, Atmosphere and Environment, Building 28, 9 Rainforest Walk, Monash University, Clayton, VIC 3800, Australia.
⁴ School of Earth, Atmosphere and Environment, Building 28, 9 Rainforest Walk, Monash University, Clayton, VIC 3800, Australia. Electronic address: joel.brugger@monash.edu.

PMID: 31279943
DOI: 10.1016/j.jhazmat.2019.06.002

Abstract

The longest-lived naturally occurring isotope of polonium is polonium-210, one of the daughters of uranium-238 (138 days half-life). As a daughter radionuclide of radon-222, polonium-210 can become enriched in pore fluids in U-bearing rocks, leading to contents in excess of 100 Bq.g^-1 in some products from the mineral, coal, oil and gas industries (e.g., anode slimes in copper refinement; sludge from the oil and gas industry). Since 2006, IAEA recommendation limits require polonium and other radionuclides from the U- and Th-series decay to be regulated for products and wastes that contain >1 Bq.g^-1, which results in the classification of large amounts of industrial products and waste as radioactive. To develop effective methods for polonium removal and/or control, it is necessary to acquire an understanding of its aqueous chemistry. Based on a review of available experimental data, we developed a self-consistent thermochemical model for polonium in inorganic aqueous solutions. Polonium exists mainly in two oxidation states in aqueous solutions: Po(IV) and Po(II). The importance of Po(II) is unique, as Te(II) or Se(II) complexes do not appear to play a significant role in aqueous solution at room temperature. The model is used to discuss polonium speciation in some environmental and process waters.

Keywords: Comparison to Pb, Se and Te; Environmental radiochemistry; Polonium aqueous chemistry; Polonium geochemistry; Thermodynamics.

Publication types

Review
Research Support, Non-U.S. Gov't