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  • Author or Editor: M. Ketterer x
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Abstract  

Plutonium isotopes were measured by alpha-spectrometry and ICP-MS in sediment samples from two European lakes: Blelham Tarn in U.K. and Stechlin lake in Germany. The ICP-MS measurements were made after alpha-spectrometry counting of the planchets. The planchets were prepared by traditional electrodeposition method after radiochemical extraction, separation and purification of the Pu fraction. A short radiochemical separation using plutonium selective resin, between the two spectrometry measures, is presented. The results show that these two complementary methods are in good agreement, the plutonium activity concentrations are the same. Alpha-spectrometry allows the 238Pu determination and ICP-MS individual measurement of 239Pu and 240Pu. 238Pu/239+240Pu and 240Pu/239Pu ratios are calculated to determine the plutonium contamination source. With the results of these two techniques, it could be demonstrate that the plutonium is of global fallout origin.

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Abstract  

A sediment core was taken to determine if sediment accumulation rates could be conducted using 240+239Pu signatures in the coastal mangrove mudflats of southeastern Brazil. The results from this study show that 240+239Pu fallout activities are sufficient and well preserved in the coastal sediments of this region. Sediment accumulation rates determined from the 240+239Pu signatures were 4.4 mm/year and 4.1 from 210Pb (CIC) method. A sediment mixing coefficient rate was calculated using chlorophyll-a profile (9.5 cm2).

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