Chemical availability of fallout radionuclides in cryoconite

Davidson, H.; Millward, G.E.; Clason, C.C.; Fisher, A.; Taylor, A.

Abstract

Atmospheric deposition on glaciers is a major source of legacy fallout radionuclides (FRNs) accumulating in cryoconite, a dark granular material with surface properties that efficiently bind FRN contaminants (specifically 137Cs; 210Pb; 241Am). Cryoconite-bound FRNs in glaciers can be released when they interact with and are transported by glacial meltwater, resulting in the discharge of amassed particulate contaminants into aquatic and terrestrial environments downstream. The environmental consequences of FRN release from the cryosphere are poorly understood, including impacts of cryoconite-sourced FRNs for alpine food chains. Consequently, there is limited understanding of potential health risks to humans and animals associated with the consumption of radiologically-contaminated meltwater. To assess the chemical availability of cryoconite-adsorbed FRNs we used a three-stage sequential chemical extraction method, applied to cryoconite samples from glaciers in Sweden and Iceland, with original FRN activity concentrations up to 3300 Bq kg−1 for 137Cs, 10,950 Bq kg−1 for unsupported 210Pb (210Pbun) and 24.1 Bq kg−1 for 241Am, and orders of magnitude above regional backgrounds. Our results demonstrate that FRNs attached to cryoconite are solubilized to different degrees, resulting in a stage-wise release of 210Pbun involving significant stepwise solubilization, while 137Cs and 241Am tend to be retained more in the particulate phase. This work provides an insight into the vulnerability of pristine glacial environments to the mobilization of FRN-contaminated particles released during glacier melting, and their potential impact on glacial-dependent ecology.

Citation

Davidson, H., Millward, G., Clason, C., Fisher, A., & Taylor, A. (2023). Chemical availability of fallout radionuclides in cryoconite. Journal of Environmental Radioactivity, 268-269(November), Article 107260. https://doi.org/10.1016/j.jenvrad.2023.107260

• Journal Article Type: Article
• Acceptance Date: Jul 21, 2023
• Online Publication Date: Aug 1, 2023
• Publication Date: Aug 1, 2023
• Deposit Date: Aug 16, 2023
• Publicly Available Date: Aug 16, 2023
• Journal: Journal of Environmental Radioactivity
• Print ISSN: 0265-931X
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 268-269
• Issue: November
• Article Number: 107260
• DOI: https://doi.org/10.1016/j.jenvrad.2023.107260
• Keywords: Health, Toxicology and Mutagenesis; Pollution; Waste Management and Disposal; General Medicine; Environmental Chemistry
• Public URL: https://durham-repository.worktribe.com/output/1718716