Using chemical fractionation and speciation to describe uptake of technetium, iodine and selenium by Agrostis capillaris and Lolium perenne

Wang, J.; Bailey, E. H.; Sanders, H. K.; Izquierdo, M.; Crout, N. M.J.; Shaw, G.; Yang, L.; Li, H.; Wei, B.; Young, S. D.

Abstract

© 2019 Elsevier Ltd To understand the dynamic mechanisms governing soil-to-plant transfer of selenium (Se), technetium-99 (99Tc) and iodine (I), a pot experiment was undertaken using 30 contrasting soils after spiking with 77Se, 99Tc and 129I, and incubating for 2.5 years. Two grass species (Agrostis capillaris and Lolium perenne) were grown under controlled conditions for 4 months with 3 cuts at approximately monthly intervals. Native (soil-derived) 78Se and127I, as well as spiked 77Se, 99Tc and 129I, were assayed in soil and plants by ICP-MS. The grasses exhibited similar behaviour with respect to uptake of all three elements. The greatest uptake observed was for 99Tc, followed by 77Se, with least uptake of 129I, reflecting the transformations and interactions with soil of the three isotopes. Unlike soil-derived Se and I, the available pools of 77Se, 99Tc and 129I were substantially depleted by plant uptake across the three cuts with lower concentrations observed in plant tissues in each subsequent cut. Comparison between total plant offtake and various soil species suggested that 77SeO42−, 99TcO4− and 129IO3−, in soluble and adsorbed fractions were the most likely plant-available species. A greater ratio of 127I/129I in the soil solid phase compared to the solution phase confirmed incomplete mixing of spiked 129I with native 127I in the soil, despite the extended incubation period, leading to poor buffering of the spiked available pools. Compared to traditional expressions of soil-plant transfer factor (TFtotal), a transfer factor (TFavailable) expressed using volumetric concentrations of speciated ‘available’ fractions of each element showed little variation with soil properties.

Citation

Wang, J., Bailey, E. H., Sanders, H. K., Izquierdo, M., Crout, N. M., Shaw, G., …Young, S. D. (2020). Using chemical fractionation and speciation to describe uptake of technetium, iodine and selenium by Agrostis capillaris and Lolium perenne. Journal of Environmental Radioactivity, 212, Article 106131. https://doi.org/10.1016/j.jenvrad.2019.106131

• Journal Article Type: Article
• Acceptance Date: Dec 6, 2019
• Online Publication Date: Dec 17, 2019
• Publication Date: 2020-02
• Deposit Date: Jan 15, 2020
• Publicly Available Date: Dec 18, 2020
• Journal: Journal of Environmental Radioactivity
• Print ISSN: 0265-931X
• Electronic ISSN: 1879-1700
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 212
• Article Number: 106131
• DOI: https://doi.org/10.1016/j.jenvrad.2019.106131
• Keywords: Waste Management and Disposal; Pollution; Health, Toxicology and Mutagenesis; Environmental Chemistry; General Medicine
• Public URL: https://nottingham-repository.worktribe.com/output/3610394
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0265931X19308197
• Additional Information: This article is maintained by: Elsevier; Article Title: Using chemical fractionation and speciation to describe uptake of technetium, iodine and selenium by Agrostis capillaris and Lolium perenne; Journal Title: Journal of Environmental Radioactivity; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.jenvrad.2019.106131; Content Type: article; Copyright: © 2019 Elsevier Ltd. All rights reserved.