A principal assumption at the basis of environmental chemistry is that contaminants transform quickly to the thermodynamic minima for their local conditions. For actinides in soils exposed to air and water these are typically oxy-hydroxide species that may be homogeneous or surface complexes and precipitates. However, bulk and microfocused XAFS and element-mapping measurements on U and Pu-containing particles from the six sites listed in the title show that, in many cases, this path is not followed. Contaminant particles are often found to have incorporated additional elements from their formation, original waste streams, or disposal processes that reflect their origin and history. This includes components of the original devices, e.g., fuel elements or thermonuclear weapons, reagents used in separations, and perhaps even the storage tanks or pipes. These traces are conserved even after decades of environmental exposure. Furthermore, the their incorporation may occur in the solid state and not require dissolution.

Speciation of U and Pu in soils from Chernobyl, Hanford, Los Alamos, McGuire, Mayak, and Rocky Flats

243rd National Meeting (2012)

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