A record of fallout 239Pu and 240Pu at World Heritage Bathurst Harbour, Tasmania, Australia

• Published in: Journal of environmental radioactivity Vol. 237; p. 106679
• Main Authors: Harrison, Jennifer J., Saunders, Krystyna M., Child, David P., Hotchkis, Michael A.C.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2021
• Subjects: 210Pb; 239Pu; 240Pu; AMS; Fallout radionuclide; Plutonium; Sedimentation; Fallout radionuclide; 210Pb; 239Pu; AMS; 240Pu; Plutonium; Sedimentation
• ISSN: 0265-931X; 1879-1700
• DOI: 10.1016/j.jenvrad.2021.106679

This study presents the first measurements of anthropogenic plutonium (239Pu and 240Pu) concentrations and atom ratios (240Pu/239Pu) for Tasmania, in sediment collected from Bathurst Harbour, in the Tasmanian Wilderness World Heritage Area, Australia. The weighted mean 240Pu/239Pu atom ratio measured at this site was 0.172 ± 0.007 which is consistent with published data from mainland Australia and global and Southern Hemisphere averages. The 240Pu/239Pu atom ratios ranged between 0.11 and 0.21 with the earliest recorded 240Pu/239Pu atom ratios being the lowest, suggesting an influence of low atom ratio fallout from nuclear testing in Australia. Post-moratorium fallout 240Pu/239Pu atom ratios were consistent with other records. Lead-210 (210Pb) sediment chronologies indicate sediment accumulation rates have increased since the early part of the 19th century at this location. [Display omitted] •Presents the first measurements of fallout plutonium concentrations and 240Pu/239Pu atom ratios in Tasmania, Australia.•Uses an estuarine sediment record from a World Heritage Area to reconstruct fallout from global nuclear weapons testing.•Early 240Pu/239Pu atom ratios indicate contribution of fallout from British testing in Australia.