236U/238U and 240Pu/239Pu isotopic ratios in small (2 L) sea and river water samples

First 236U data from the Arctic Ocean and use of 236U/238U and 129I/236U as a new dual tracer

“…The 236 U/ 238 U ratios of the samples collected in 2011/12 in the Arctic Ocean cover the widest range of ratios reported so far in the open ocean 2,3,5,23,24 (between (5±5) and (3840±260) ×10 -12 , Table 1S, Figure 2). Concentrations of 129 I also display a wide range of values (between (0.16±0.08) ×10 7 and (804±10) ×10 7 at•kg -1 ) and 129 I/ 236 U ratios span from 3±1 to 294±10.…”

“…In recent years, an increasing number of studies have measured the anthropogenic occurrence of 236 U (T1/2=23 Ma) in the ocean and indicated its potential as an oceanographic tracer [1][2][3][4] . The general suitability of 236 U on a basin-wide scale has been demonstrated recently with the presentation of a first transect through the western North Atlantic Ocean 5 .…”

Analysis of 236U and plutonium isotopes, 239,240Pu, on the 1 MV AMS system at the Centro Nacional de Aceleradores, as a potential tool in oceanography

“…the measured ones in [17] in samples mostly affected by the general fallout. It is noteworthy that the IAEA-381 sample, with a clear influence of Sellafield discharges, has a 236 U/ 239 Pu ratio in the same range.…”

“…It is important to note the different physical-chemical behavior of uranium and plutonium, which might be particularly important for non steady state systems, such as seawater masses. Indeed, in surface seawater, the 236 U presence is enhanced by at least a factor of 2 over 239 Pu, due to the conservative nature of uranium and to the particle-reactive behavior of plutonium, which can be further strengthen in areas with a remarkable biological productivity [17]. For marine sediments, it can be deduced, from published 236 U and 239,240 Pu data, a few results for reference materials provided by the International Atomic Energy Agency (IAEA) and affected by different local sources.…”

Determination of plutonium isotopes in environmental samples with triisooctylamine and alpha spectrometry

“…Eigl et al measured higher concentrations of 239?240 Pu in the water from the Danube River of 2.7 ± 0.7 lBq L -1 but close to the mouth at the Black sea and 4.6 ± 0.7 lBq L -1 for the Black sea (10 m depth, near Vadu, Romania) [28]. The analyses of the filter ashes confirmed the presence only of 239?240 Pu in the range 0.077-0.13 Bq kg -1 (filter ash) ( Table 4).…”