Accumulation of Hexavalent Uranium by Highly Organic Soils at the Needle's Eye Natural Analogue Site, South West Scotland

Muir, M. R. , MacKinnon, G. , Uhrin, D. and Graham, M. C. (2022) Accumulation of Hexavalent Uranium by Highly Organic Soils at the Needle's Eye Natural Analogue Site, South West Scotland. World Congress of Soil Science 2022, Glasgow, UK, 1-5 Aug 2022.

Abstract

Nuclear power has the potential to provide electricity with lower emissions of greenhouse gases than electricity generated by combustion of fossil fuels. However, a downside of nuclear power generation is the production of waste products which will be radioactive for long timescales into the future. Safe storage of generated waste is a significant consideration for the future use of nuclear power. Studies have been undertaken at the Needle's Eye Natural Analogue site in Southwest Scotland to evaluate if the highly organic soils (loss on ignition ~ 80%) at the site are an effective barrier for uranium (U), a major component of nuclear waste. Analysis of soils by x-ray absorption spectroscopy (XAS) demonstrated that, despite the dominant waterlogged and anaerobic conditions in the soil at the site, conducive to the reduction of U to U(IV), the majority of U in the upper 30 cm of the soil profile was present as U(VI) complexed with oxygen functional groups of soil organic matter (SOM). Results of SOM characterization (UV/Vis spectroscopy, FTIR and ¹H NMR) demonstrated that SOM in the region of the soil profile with greatest U accumulation was relatively enriched with carboxylate functional groups and fulvic acid organic matter compared to deeper in the soil profile where aromatic structures and humic acids became more prominent. The results indicate that highly organic soils can be an effective barrier to the mobility of U in the surface environment, with implications for the future selection of sites for long-term storage of nuclear waste.

• Item Type: Conference or Workshop Item
• Additional Information: Funded by NERC, EA and RWM as part of the Radioactivity and the Environment (RATE) “Long-Lived Radionuclides in the Surface Environment (Lo-RISE)” project.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: MacKinnon, Dr Gillian and Muir, Dr Michael
• Authors: Muir, M. R., MacKinnon, G., Uhrin, D., and Graham, M. C.
• Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
• College/School: College of Social Sciences > School of Social & Environmental Sustainability; College of Science and Engineering > Scottish Universities Environmental Research Centre
• Research Group: Environmental Science and Sustainability
• Copyright Holders: Copyright © 2022 The Authors
• Publisher Policy: Reproduced with the permission of the authors

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