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Post-World War II Uranium Changes in Dated Mont Blanc Ice and Snow

2001; American Chemical Society; Volume: 35; Issue: 20 Linguagem: Inglês

10.1021/es0109186

1520-5851

Carlo Barbante, Katja Van de Velde, Giulio Cozzi, Gabriele Capodaglio, Paolo Cescon, F. Planchon, Sungmin Hong, Christophe Ferrari, Claude F. Boutron,

Radioactive element chemistry and processing

Recent controversies concerning the possibility of environmental contamination due to the use of uranium in classical weaponry have led us to realize that there is a lack of time series for this metal from environmental archives. We have therefore performed analysis of a dated 140 m-long ice/snow core that was drilled in 1994 at a cold high altitude site (4250 m) near the summit of Mont Blanc in the French−Italian Alps. Ultraclean analytical procedures were employed in our analyses. Uranium concentrations were determined by inductively coupled plasma sector field mass spectrometry. In ice dating from before the 1940s, uranium concentrations are found to have remained fairly constant and can be explained simply by a crustal contribution. For the post-World War II layers, on the other hand, the data show large excesses above crustal contributions. These uranium excesses are attributed to tropospheric transport of dust emitted during extensive mining and milling operations which took place in the GDR and to a smaller extent in France at that time. There is no enhancement in uranium concentrations in the ice layer in which fallout from the 1986 Chernobyl accident was previously identified from a gross β activity vs depth profile.