PLUTONIUM CONCENTRATION IN SEDIMENT CORES COLLECTED IN THE MEDITERRANEAN-SEA

As is well known, the determination of plutonium isotopes in the marin e environment is of great importance to calculate the contamination du e to the nuclear industry and to better understand sedimentation proce sses. In the last 20 years sea sediment cores have been collected in d ifferent areas of the Mediterranean Sea by four Italian research teams . The sampling depth ranged from 50 to 2800 m and the core lengths wer e 10-30 cm. The radioanalytical procedures were based on plutonium sep aration by anion exchange resins or by extraction chromatography with Microthene-TOPO; plutonium electroplating was performed before alpha-s pectrometry. The final chemical yields were determined by spiking with Pu-236 or Pu-242. In some cases Pu-238 could be detected. As far as t he vertical profiles are concerned, no significant subsurface maxima r esulted for the cores collected at greatest depth; on the contrary int eresting peaks were found for cores collected at 50-100 m depth.