C. Triulzi

Plutonium concentration in sediment cores collected in the Mediterranean Sea

As is well known, the determination of plutonium isotopes in the marine environment is of great importance to calculate the contamination due to the nuclear industry and to better understand sedimentation processes. In the last 20 years sea sediment cores have been collected in different areas of the Mediterranean Sea by four Italian research teams. The sampling depth ranged from 50 to 2800 m and the core lengths were 10–30 cm. The radioanalytical procedures were based on plutonium separation by anion exchange resins or by extraction chromatography with Microthene-TOPO; plutonium electroplating was performed before α-spectrometry. The final chemical yields were determined by spiking with 236Pu or 242Pu. In some cases 238Pu could be detected. As far as the vertical profiles are concerned, no significant subsurface maxima resulted for the cores collected at greatest depth; on the contrary interesting peaks were found for cores collected at 50–100 m depth.

A radioecological survey of Northern and Middle Adriatic Sea before and after the Chernobyl event (1979–1990)

Abstract Investigations to determine the presence and distribution of some anthropogenic pre- and post-Chernobyl radionuclides and to evaluate their behaviour and transport within different environmental components were conducted between 1979 and 1990 in Northern and Middle Adriatic Sea. Although the Chernobyl accident introduced many radionuclides into this environment, most of them had very short half lives and only Ru-103, Ru-106, Ag-110m, Cs-134 and Cs-137 were fully investigated on a long term basis due to their long persistency and abundance. In particular, neutron activation products, such as Ag-110m and Cs-134, not present in the environment before the event, were fully detected for the first time in the ecosystem shortly after the contamination. The results highlight the distribution of the considered gamma emitting radioisotopes in samples of seawater, sediments, mixed plankton, icthyofauna and benthic macrofauna, and allow a complete mapping and assessment of the Adriatic radiocontamination after 10 years of intense and extended monitoring of the ecosystem.

90Sr, 137Cs, 238Pu, 239+240Pu and 241Am levels in terrestrial and marine ecosystems around the italian base in Antarctica

During the last 14 years the Radioecology Laboratory of Parma University and the General Chemistry Institute of Urbino University collaborated on a radioecological programme having the aim to observe the evolution of antropogenic radioactivity in Antarctica in the period 1987-2001. The artificial radionuclides considered were 90Sr, 137Cs, 239+240Pu,238Pu and 241Am. The contamination seems to be higher in the continental environment rather than in the marine one. Mosses, algae and lichens showed the highest values for all radionuclides analyzed. The results prove that the Antarctic continent is interested by radioactive pollution. As far as 137Cs is concerned, a progressive decrease was observed.

The fate of plutonium, 241 Am, 90 Sr and 137 Cs in the Antarctic ecosystem

A radioecological survey around Terra Nova Bay showed that 239 + 240Pu, 238Pu, 241Am, 90Sr and 137Cs activities were detectable in nearly all the samples. The 239 + 240Pu and 241Am concentrations in seawater were slightly lower than those in the northern Pacific Ocean. The activity level of 239 + 240Pu, 241Am and 137Cs in Antarctic sediments (Ross Sea) was c. 5–20 times lower than in northern Adriatic sediments (Mediterranean Sea), but the 238Pu activities were relatively high. The 90Sr concentrations in all the sediment samples from both the Ross and Adriatic seas tended to be low which might be due to an easier exchange of 90Sr in seawater. On the other hand, high concentrations were detected in Antarctic mosses, lichens and algae and their activity levels are comparable to those in central Italy. The radionuclide ratio analyses show that the major part of 239 + 240Pu, 241Am, 90Sr and 137Cs is the result of nuclear weapon tests. A higher 241Am/239 + 240Pu ratio might be due to the fallout of earlier atmospheric nuclear tests. The 238Pu239 + 240Pu ratio in the Antarctic matrices is about seven times higher than in the Northern Hemisphere and this could suggest that the major part of 238Pu originated from the SNAP-9A satellite accident.

Italian Antarctic Research Program: Environmental radioactivity survey around the Italian base (1987–1991) Terra Nova Bay — Ross sea region

Investigations have been carried out by the Italian Antarctic Research Program to determine the natural and artificial radioactivity levels of both the marine and terrestrial environments. Also, natural and anthropogenic fluxes of aerosol particles onto the Antarctic surface have been examined.

A Chemical Characterization of A Lagoon Ecosystem: The Sacca Di Goro (Po River Delta, Italy)

Abstract This work reports on the results of a preliminary estimate of the presence and distribution of common and rare elements in a typical estuarine environment of the Po River Delta. Different environmental compartments (sediment, water, macroalgae and benthic animals) were considered, and analysis conducted on samples taken at two different sites characterized by low and high hydrodynamic regime. Resulting evidence of differences between the matrices, especially in relation to their different nature and sampling site are given.

Radioactive and Stable Isotopes in Abiotic and Biotic Components of Antarctic Ecosystems Surrounding the Italian Base

Abstract Results concerning the analysis of natural (K-40, Th-232, U-238) and anthropogenic (Sr-90. Cs-137, Pu-238, Pu-239, 240) radioactivity determined in samples collected during the PNRA (National Program for Antarctic Research) 1990–91 and 1991–92 Scientific Expeditions, are presented. The data refer to samples of the terrestrial, lacustrine and marine ecosystems surrounding the Italian Base in the Terra Nova Bay (Ross Sea) territory with special emphasis on the Cs-137 biogeochemical behaviour. In particular, the role of the organic substance in the radionuclide transfer has been evaluated through statistical correlation analysis between the Cs-137 concentrations and organic matter, organic carbon and nitrogen contents determined in samples of marine and lacustrine sediments.

Radioecological Research on the Marine Environment Facing the Italian Base in Antarctica (1989–91)

The results of the analysis of both natural (Th-232, U-238 and K-40) and artificial (Cs-137) radioactivity contained in samples collected during the 1989-90 and 1990-91 PNRA Scientific Campaigns in the Terra Nova Bay (Ross Sea) marine ecosystem, are presented in this paper. The data refers to samples of sea water, pink water, sediments and organisms belonging to demersal ichthyofauna (Pagothenia bemacchii. Chionodraco hamatus) and soft bottom macrofauna (Adamussium colbecki) collected in different coastal and off shore stations of the area investigated. Some sea water samples collected on the way to subAantarctic areas were also considered. The radiocontamination detected in sediments was correlated to the quantifies of organic matter, organic carbon and nitrogen contained in the samples

Evolution of persistent Anthropogenic radioactivity in Antarctic ecosystems

The primary objective of this study was to observe the evolution of anthropogenic radioactivity contamination in the Antarctic continent throughout the period 1997–1999. Moreover, results have been compared with those obtained for previous expeditions, starting from 1987. As far as 137Cs is concerned, interesting considerations could be made due to the great amount of available data. On the whole, radioactive contamination seems to be higher in continental than in marine environments. For lake algae, contamination seems to decrease gradually in the order: Tarn Flat, Edmondson Point, Carezza Lake. Focusing on 137Cs activity data, a clear temporal decreasing trend was observed in all samples: for sea water, values decreased from mean values of 0.9 Bq/m3 in 1987 to 0.5 Bq/m3 in 1999, a 56% decrease (20% of the total is due to natural decay of 137Cs). For lake waters and lake algae, the decreases are higher (80 and 30%, respectively) and the same can be assessed for sediments and soils, even if the resulting distributions are more complicated. The highest values for all radionuclides analysed were detected in terrestrial organisms (mosses, lake algae, and lichens). As a consequence, these matrices appear to be good bioindicators of radioactive contamination. Finally, although the Antarctic continent is affected by some degree by anthropogenic radioactive pollution, our results for 137Cs show that we are facing a progressive decrease. Moreover, contamination in other parts of the world is much higher: from 6–10 times in the Mediterranean Sea and 20–50 times in the North Sea and Black Sea.

Radioactive Isotopes of Strontium, Caesium and Plutonium in Sediments of the Northern Adriatic Sea

Abstract Sediment samples of different strata (0–3 and 12–15 cm) were collected between 1990 and 1992 during seasonal cruises in the Northern Adriatic Sea. A complete mapping of the Sr-90, Cs-137, Pu-238 and Pu-239(240) concentrations was obtained for samples covering a wide area, stretching from the Gulf of Trieste towards the Ancona shoreline. Sr-90 concentrations varied between 1.5 and 6.5 Bq kg−1 dw, Cs-137 was in the range 0.9–38.9 Bq kg−1 dw, Pu-239(240) in the range 0.08-1.5 Bq kg−1 dw and Pu-238 around 0.03 Bq kg−1 dw. Special reference was also put on the comparison between the off-shore environment and data obtained from samples collected inside the Po river delta. in spite of the major accumulation of Cs-137 inside the estuarine environment, higher concentrations of strontium and plutonium isotopes were detected in the offshore environment.