The transport and fluvial redistribution of Chernobyl-derived radiocaesium within the River Wye basin, UK

title: The transport and fluvial redistribution of Chernobyl-derived radiocaesium within the River Wye basin, UK

Author: J.S. Rowan, D.E. Walling

Reference: Science of The Total Environment, Volume 121, 30 June 1992, Pages 109-131

DOI: http://dx.doi.org/10.1016/0048-9697(92)90310-O

Keywords: Wye; Chernobyl; radiocaesium; sediment-associated; redistribution

Abstract: Relatively little attention has been given to the long term prospect of fluvial transport processes redistributing Chernobyl-derived radiocaesium within the UK. Work undertaken within the Wye basin, central Wales, demonstrates a complex distribution of fallout at the catchment scale, with the bulk of the deposition concentrated in a narrow north-south band, situated in the west central areas of the basin, which contained in excess of 1500 Bq m⁻² of ¹³⁴Cs. Fluvial transport and redistribution of this material was demonstrated by river sampling during the winter of 1988/89, when the radiocaesium content of suspended sediment transported by the River Wye (≈ 30–50 mBq g⁻¹ of ¹³⁷Cs) remained 3–5-times higher than pre-Chernobyl levels. Floodplain reaches displayed variable levels of secondary contamination, dependent upon the upstream supply of radiocaesium and local morphological controls. Accordingly, the highest ¹³⁴Cs inventories within the basin (> 6000 Bq m⁻²) were associated with rapidly accreting floodplain sites. A number of these sites experienced only limited amounts of direct atmospheric fallout. The importance of fluvial redistribution as a secondary contamination mechanism is thus highlighted.

URL: http://www.sciencedirect.com/science/article/pii/004896979290310O