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| Titel |
The environmental behaviour of beryllium-7: implications for its use as a soil erosion tracer |
| VerfasserIn |
A. Taylor, W. H. Blake, M. J. Keith-Roach, L. Couldrick |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250044035
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| Zusammenfassung |
| Beryllium-7 is a cosmogenic fallout radionuclide (FRN) that can be employed as a tracer in
soil erosion studies. Owing to its short half life (53.3 days), estimates of soil redistribution
from a single event or wet season can be derived, complimenting medium-term 137Cs-based
data. The ability of 7Be to provide robust quantification of soil erosion over short timescales
is vital when considering the potential for climate change to influence precipitation patterns
and shifts in landuse. A major requirement of the technique is the capacity of the
FRN to adsorb to soil particles and remain bound during transport. To date, little
attention has been given to the geochemical behaviour of 7Be. The research reported
here aims to develop knowledge of 7Be adsorption behaviour in a range of soil
types and environmental conditions to support its use as a tracer at the catchment
scale.
Four agricultural soils common to south Devon, UK were selected for experiments
designed to investigate7Be solid-phase partitioning in soils and tracer stability under
changing environmental conditions. Preliminary results from two key aspects of the work are
reported here. The BCR three-step sequential extraction procedure was adopted to investigate
7Be adsorption to operationally-defined soil fractions. Early findings indicate that 7Be is
largely associated with Fe/Mn fractions with up to 67% adsorbed to this reducible phase. This
supports the use of 7Be as a soil erosion tracer at the slope-scale but may have implications
for 7Be mobility under reducing conditions in deposition zones. In addition, batch
experiments have been undertaken to evaluate 7Be behaviour in the dissolved phase focusing
upon the role of DOC as a complexing agent in soil solutions since soil solution DOC
can increase following manure and compost application. Results will be used to
underpin the application of 7Be as a sediment tracer within an Interreg IVA funded
research programme addressing wetland restoration as a catchment management tool. |
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