210Po sequential extraction applied to wetland soils at uranium mining sites

• Published in: Journal of environmental radioactivity 2019-04, Vol.199-200, p.1-6
• Main Authors: Le, Thi-Hong-Hanh, Michel, Hervé, Champion, Julie
• Format: Article
• Language: English
• Subjects: Polonium-210; Sequential extraction; Soils; Uranium mining
• ISSN: 0265-931X; 1879-1700
• DOI: 10.1016/j.jenvrad.2018.12.027

Former uranium mining activities have led to the presence of naturally occurring nuclides embedded in soil. Such activities have also modified the secular equilibrium between radionuclides in 238U decay series. The objective of this paper is to quantify the long-term effect of former uranium mining activities on the behavior of the final radionuclide in the 238U-series, i.e. polonium-210 (210Po), present in soils. Soil samples are extracted from two uranium sites in France, specifically a quarried site and a natural site. The polonium distribution is studied within the various soil fractions, namely: water soluble, exchangeable, bound to carbonates, bound to iron/manganese oxides, bound to organic matter, and residual. 210Po is mainly found in the residual fraction of both study sites (87–90%), followed by the carbonates fraction (5–9%). The 210Po activity in the other fractions is very small in comparison with total activity. •Total activity concentration of 210Po in the soil samples from two uranium sites in France was determined.•The mobility of 210Po has been evaluated in soil samples by applying sequential extraction procedure.•A certified reference material was used to validate the method, showing good agreement with the recommended values.•210Po was mostly found in the residual fraction, followed by the carbonates fraction.