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Fallout radionuclides in Mediterranean sediments

Conference ·
OSTI ID:7210946

The rates at which fallout Pu nuclides are being transferred to the sediments of the Mediterranean are considerably less than those which apply generally to the Atlantic Ocean. The lack of variation in the ratio Pu 239,240/Cs-137 in many of the sediment cores could be interpreted to suggest that Pu and Cs-137 are being delivered to the sediments by compositionally similar particle populations. The nuclide burden in the sediments varies surprisingly little over a wide range of depths and locations and the actual variation is consistent with varying particle trapping efficiencies for sediment-dwelling organisms. The vertical nuclide distribution patterns in the sediments nowhere show indications of high sedimentation rates and are explainable in terms of variable degrees of organism burial by bioturbation. The ratios Am 241/Pu 239,240 measured in the sediments imply that Am is being transferred to the sediments at rates between 4 and 9 times greater than those for Pu. If the vertical mixing of particles in the sediments implied in these radionuclide data is indeed taking place in sediments which are, in fact, accumulating much more slowly than the particle mixing rates, then this has implications for detailed stratigraphic interpretations of the sediment record.

Research Organization:
Woods Hole Oceanographic Institution, MA (USA)
OSTI ID:
7210946
Report Number(s):
COO-3563-50; CONF-7610109-2
Country of Publication:
United States
Language:
English