Association of fallout 239+240Pu and 241Am with various soil components in successive layers of a grassland soil

Abstract

The association of 239+240Pu and241 Am from the global fallout with various soil components was investigated in six successive layers of an undisturbed grassland soil (Alfisol) from 0 to 30 cm by a sequential extraction procedure. In this way, the fractions readily exchangeable, bound to carbonates, bound to iron and manganese oxides, bound to organic matter, and residual (mineral) were determined. The results revealed that these radionuclides are in most soil layers primarily attached to the soil organic matter (in general >57%) but to a considerable extent also attached to oxides and minerals. As a result, the readily exchangeable fraction of these actinides 30-40 years after their deposition is rather low (for Pu, <1%). Significant differences between the partitioning of Pu and Am are observed for all fractions, even though they are rather small for the bound to organic matter fraction [with the exception of the 5-10-cm layer in the Ah horizon, where much more Pu (67%) than Am (18%) is associated with organic matter]. In the fraction bound to oxides, more Am is found than Pu; in the residual fraction (minerals) of most soil layers, more Pu than Am is present. In all soil layers, the readily exchangeable fraction of Am is significantly higher than that of Pu (on average by a factor of 7). The results are also discussed in relation to the long-term vertical migration rates as determined recently for both radionuclides in the same soil and with respect to possible soil reclamation procedures.

Anthropogenic radionuclide emissions into the environment

“…2 with the relative activity development as a function of time. The calculated and measured 241Am/Z39+Z4~ ratio is additionally in good agreement with data from Bunzl et al (1995) and shows clearly that 241Am measured in soil samples in central and western Europe can be well explained via support from decaying 241pu initially released during the surface A-bomb testing period. It can be concluded consequently .…”

Transuranic and fission product contamination in lake sediments from an alpine wetland, Boréon (France)

“…Even though this influence would be expected to vary considerably between caesium, strontium and transuranics, the general behaviour of these elements is here the same (Bunzl et al, 1995;Szabo et al, 1997).…”

Plutonium AMS measurements in Yangtze River estuary sediment

“…It has been widely employed because it binds strongly to particles and it may be detected by c-ray counting without any need for chemical preparation of the sample. There have been some reports of using a-particle counting to measure 239+240 Pu concentrations [11][12][13], although this has not been widely adopted for soil and sediment tracing because of the low activity of plutonium and a Pu and 240 Pu measurements with higher throughput and better sensitivity than for 137 Cs or a-particle counting of Pu. This capability is now allowing the potential advantages of Pu over 137 Cs to be realized for tracing soil erosion and sediment transport (e.g.…”