Plutonium and americium concentrations and vertical profiles in some Italian mosses used as bioindicators

We have examined the uptake of actinide elements Am and, Pu by different species of lichen and moss collected in two locations (Urbino, Central Italy; Alps region, North-east Italy). Plutonium and americium were separated and determined by extraction chromatography, electrodeposition and alpha-spectrometry. This paper summarizes our results with a special emphasis on the vertical profiles of these actinides in two different species of mosses. Several 1–2 cm depth sections were obtained and dated by210Pb method. A typical peak for239,240Pu and241Am was found in the very old moss species (“Sphagnum Compactum”) at a depth corresponding to the period 1960–1970 which was the period characterized by the maximum nuclear weapon tests. In a younger moss species (“Neckeria Crispa”) no peak was observed and the regression curves showed that Am is more mobile than239,240Pu and238Pu.