Controls on the distribution of 7Be for an improved understanding of sediment and associated contaminant storage

ORCID

Abstract

Purpose: Beryllium-7 has been widely applied as sediment tracer in river basins, however, factors influencing its geochemistry in this context have rarely been addressed. We investigated sediment-water interactions controlling the distribution of 7Be in channel sediments for improved storage time and particulate contaminant dynamic assessments in a catchment affected by legacy and contemporary mining pollution. Methods: The investigation was undertaken in the River Fal, UK, to assess sediment storage times and particulate contaminant dynamics. Samples were collected and analysed for 7Be, 137Cs, 210Pb and 238U by gamma spectrometry, aqua regia extractable P, As, Fe, Cu, Pb, Sn and Zn by inductively coupled plasma (ICP) spectrometry and Total Organic Carbon (TOC) by CHN analyser. Particle size distribution (PSD) and the 1 mol L− 1 HNO3 extractable Fe and Mn fractions were analysed by laser diffraction and ICP, respectively, to assess relationships with the radionuclide activities. Dissolved and the 1 mol L− 1 HCl extractable 9Be was quantified to determine its distribution coefficients (Kd). Results: Beryllium-7 was significantly correlated with the specific surface area (SSA), TOC and the Fe and Mn extractable fractions. A strong inverse correlation between the 9Be Kd and suspended sediment concentration (SSC) demonstrated the particle concentration effect. Suspended sediments (SS) showed higher SSA than the channel bar sediments (CBS). Storage times and the proportion of recently deposited sediments (% RDS) were estimated using different methods for addressing particle size effects, which were not statistically different. Conclusions: Occurrence of particulate contaminants was related to two dominant sources and processes: (1) in the upstream site, co-precipitation with Fe-oxides and Organic Matter (OM) enrichment; and (2) in the lower site, reworking from historic polymetallic mining during high flow events with wider relevance to legacy pollution challenges in mine-impacted rivers.

Publication Date

2026-03-02

Publication Title

Journal of Soils and Sediments

Volume

26

Issue

3

ISSN

1439-0108

Acceptance Date

2026-01-30

Deposit Date

2026-05-13

Embargo Period

2027-03-02

Funding

E. Munoz-Arcos acknowledges the support of the Agencia Nacional de Investigación y Desarrollo (ANID, Chile) through the PhD scholarship ID 72210264. The work represents a contribution to the joint International Atomic Energy Agency and UN FAO Coordinated Research Programme D1.50.18 “Multiple Isotope Fingerprints to Identify Sources and Transport of Agro-Contaminants”. We are also indebted to landowners Roger and Tanya Olver and Richard Bray for providing sites for river monitoring and access to sampling sites. Richard Hartley and Rupert Goddard are also gratefully acknowledged for helping with fieldwork. William H. Blake acknowledges the support of fellow Advisory Board members of the International Sediment initiative (ISI), a flagship programme of the UNESCO Intergovernmental Hydrological Programme Flagship, for steer on strategic development of sediment management tools.

Keywords

Beryllium-7, Radionuclides, Sediment tracing, Streambed colmation, Trace metals, Uranium

This document is currently not available here.

This item is under embargo until 02 March 2027

Share

COinS