Search

Surface, intermediate and near-bottom water samples were collected at two of the North East Atlantic radioactive waste dumping sites (47 ◦ 14'N, 05 ◦ 33'W and 45 ◦ 27'N, 06 ◦ 16'W) in the course of a sampling campaign in June-July 1998. Analysis of 239,240 Pu concentrations show no significant differences with respect to measured concentrations in waters taken from control (background) stations well removed from the dumping sites.

New data on the concentrations of key fission/activation products and transuranium nuclides in samples of soil and water from the Semipalatinsk Nuclear Test Site are presented and interpreted. Sampling was carried out at Ground Zero, Lake Balapan, the Tel’kem craters and reference locations within the test site boundary well removed from localised sources. Radionuclide ratios have been used to characterise the source term(s) at each of these sites. The geochemical partitioning of plutonium has also been examined and it is shown that the bulk of the plutonium contamination at most of the sites examined is in a highly refractory, non-labile form.

The assessment of the water transport of coastal pollution from European nuclear reprocessing facilities to the Arctic Seas can be achieved by the analysis of conservative radionuclides, such as 90 Sr, 137 Cs and 99 Tc. By obtaining their isotopic signatures in different water masses, it is possible to determine the present contribution of these radionuclides by a known source term and to differentiate this from other inputs. However, in recent years, relatively few environmental measurements have been made of 90 Sr resulting from the discharges by the British Nuclear Fuels plc plant at Sellafield, UK. In 1995, a collaborative expedition was carried out in the northern Irish Sea (and surrounding coastal waters) to determine 90 Sr concentrations in surface sea water samples. The results of this survey, and an intercomparison of the analytical data are presented, together with 137 Cs/ 90 Sr activity ratios. Information concerning the isotopic signature in different water masses enables an assessment of the extent of transport of these radionuclides out of the Irish Sea and the potential source term to the Arctic that this represents.

Particular atmospheric conditions produce frequent storm surges in the Lagoon of Venice, locally called “acqua alta”: the highest event of this kind was registered in 1966. The process became of some importance in the last 100 years, when man-made subsidence caused a gradual sinking of the town and lagoon's bed. Four cores were collected in a range of intertidal environments of the Northern lagoon to undertake radionuclide studies using profiles of natural 210Pb (using the Constant Rate of Supply and Constant Initial Concentration models) and anthropogenic 137Cs. The best agreement between the three dating methods was found at San Giacomo, an eroding saltmarsh at the edge of a navigation channel, with a sedimentation rate ranging from 0.22 to 0.29 cm yr−1. This site recorded the flood of 1966 as a characteristic break in the 210Pbex profile, as dated by the CRS model. For the Cona tidal flat, both the CRS model and the position of the Cs peak-marker gave similar accretion rates, 0.16 and 0.18 cm ...