ORCID

Abstract

Purpose: The aims of this research were to assess the sources of variability of particulate FRNs ( 7Be, 210Pb ex and 137Cs) in river channels, the influence of sediment properties such as particle size distribution (PSD) and organic matter (OM) on FRN distributions, and to discuss the implications for sediment tracing in rivers. Methods: Suspended and channel bed sediment samples were collected in the River Avon (Devon, UK) during five strategic surveys involving a wide variation of river flows, including flood conditions. Particulate matter was analysed for 7Be, 210Pb ex and 137Cs by gamma spectrometry, PSD by laser diffraction, and organic constituents, total organic carbon (TOC) and total nitrogen (TN) by elemental analysis. Results: FRNs activity concentrations vary significantly both spatially, characterised by changes in activity concentrations within and between locations, and temporally, with changes during the storm hydrograph and between seasons. Variability was attributed to changes in sediment sources and, on some occasions, to significant correlation of activity concentrations with sediment properties. The results also highlighted the influence of changes in channel characteristics and the magnitude and frequency of floods on FRN distributions. Conclusion: In the context of sediment tracing, attention should be given to seasonal changes in riverine conditions that have the potential to affect 7Be and 137Cs conservativeness. Application of FRNs in sediment fingerprinting studies should be accompanied by appropriate temporal characterisation of potential sediment sources. Finally, potential contribution of 7Be-depleted sediment from channel resuspension to the suspended load should also be considered.

Publication Date

2024-08-07

Publication Title

Journal of Soils and Sediments

Volume

24

Issue

12

ISSN

1439-0108

Acceptance Date

2024-07-30

Deposit Date

2024-10-02

Embargo Period

2025-08-07

Funding

E. Munoz-Arcos acknowledges the support by the Agencia Nacional de Investigaci\u00F3n y Desarrollo (ANID, Chile) through the PhD scholarship ID 72210264. The work represents a contribution to the Joint UN Food and Agricultural Organisation / International Atomic Energy Agency Coordinated Research Programme D1.50.18 \u201CMultiple Isotope Fingerprints to Identify Sources and Transport of Agro-Contaminants\u201D. We are also indebted to landowners Charles Smith, Tom Burner and Adrian Martin for providing sites for river monitoring and access to sampling sites. Alice Kalnins, Rupert Goddard, Jess Kitch and Xing Hua are also acknowledged for helping in the field, and Billy Simmonds for analytical support regarding CHN analyses. The authors thank the reviewers for their valuable comments.

Keywords

Channel bed, Gravel bed, Radionuclides, Sediment tracing, Sediments

First Page

3824

Last Page

3840

Additional Files
PaperWP2_JSS_VariabilityofFRNs_Clean.pdf (1162 kB)
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Additional Files

PaperWP2_JSS_VariabilityofFRNs_Clean.pdf (1162 kB)

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