Application of a magnetic extraction technique to assess radionuclide-mineral association in Cumbrian shoreline sediments

McCubbin, David, Leonard, Kinson S, Young, Alan K, Maher, Barbara A and Bennett, Stephen (2004) Application of a magnetic extraction technique to assess radionuclide-mineral association in Cumbrian shoreline sediments. Journal of Environmental Radioactivity, 77 (2). pp. 111-131. ISSN 0265-931X

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Abstract

An assessment has been made of the association of (239+240)Pu, 241Am and 210Po (in secular equilibrium with 210Pb) with iron minerals using a magnetic extraction technique. Grab samples of beach sand from the Cumbrian (UK) coastline were subjected to successive extractions with an approximately 0.1 T ferrite magnet and an approximately 0.3 T rare-earth magnet procedure to separate magnetic iron oxide minerals. Radionuclide concentrations in the magnetic extracts were enhanced (by approximately 4-6-fold) relative to the residue. Those in the approximately 0.1 T magnet extracts were broadly similar to those in the antiferromagnetic material extracted by the approximately 0.3 T magnet, despite the very large differences in magnetic property values between the two fractions (one to two orders of magnitude). The percentage of magnetic material in terms of mass was small and therefore, the majority of these radionuclides (on average 88%) were associated with the residue. Removal of stable Fe was incomplete. Given that the radionuclides may also bind to paramagnetic (nonmagnetic) Fe minerals, the data were extrapolated by normalising the results to quantitative Fe removal. This yielded average values of 37%, 45% and 46% for (239+240)Pu, 241Am and 210Po(210Pb), respectively, as upper limits for the fraction associated with magnetic + nonmagnetic Fe minerals. There are significant uncertainties inherent in quantifying data from this extraction technique. Nevertheless, it seems reasonable to conclude that radionuclide association with Fe minerals is unlikely to have a significant impact upon the physical dispersion of sediment contaminated by Sellafield discharges in the Irish Sea. However, it may be an important factor in governing Pu redox and redissolution behaviour.

Item Type:	Article
Uncontrolled Keywords:	analysis,bathing beaches,methods,analysis,analysis,magnetics,nuclear reactors,particle size,analysis,analysis,analysis,united kingdom,analysis
Faculty \ School:	Faculty of Science > School of Environmental Sciences Faculty of Science
Depositing User:	LivePure Connector
Date Deposited:	19 Feb 2020 07:55
Last Modified:	22 Oct 2022 05:52
URI:	https://ueaeprints.uea.ac.uk/id/eprint/74253
DOI:	10.1016/j.jenvrad.2004.02.006

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