Sources of the transuranic elements plutonium and neptunium in arctic marine sediments.
We report here thermal ionization mass spectrometry measurements of {sup 239}Pu, {sup 240}Pu, {sup 241}Pu, {sup 242}Pu, and {sup 237}Np isolated from oceanic, estuarine, and riverine sediments from the Arctic Ocean Basin. {sup 238}Pu/{sup 239+240}Pu activity ratios are also reported for alpha spectrometric analyses undertaken on a subset of these samples. Our results indicate that the Pu in sediments on the Alaskan shelf and slope, as well as that in the deep basins (Amerasian and Eurasian) of the Arctic Ocean, has its origin in stratospheric and tropospheric fallout. Sediments from the Ob and Yenisei Rivers show isotopic Pu signatures that are distinctly different from those of northern-hemisphere stratospheric fallout and indicate the presence of weapons-grade Pu originating from nuclear fuel reprocessing wastes generated at Russian facilities within these river catchments. Consequently, sediments of the Eurasian Arctic Ocean, particularly those in the Barents and Kara Seas, probably contain a mixture of Pu from stratospheric fallout, tropospheric fallout, and fuel-reprocessing wastes of riverine origin. In particular, the {sup 241}Pu/{sup 239}Pu ratios observed in these sediments are inconsistent with significant contributions of Pu to the arctic sediments studied from western European reprocessing facilities, principally Sellafield in the UK. Several other potential sources of Pu to arctic sediments can also be excluded as significant based upon the transuranic isotope ratios presented.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 943046
- Report Number(s):
- ANL/ER/JA-37032; MRCHBD; TRN: US1000532
- Journal Information:
- Mar. Chem., Vol. 69, Issue 2000; ISSN 0304-4203
- Country of Publication:
- United States
- Language:
- ENGLISH
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