Retention of $^{10}$Be, $^{137}$Cs and $^{210}$Pb$_{xs}$ in soils: Impact of physico-chemical characteristics

International audience; The $^{10}$Be, $^{137}$Cs and $^{210}$Pb$_{xs}$ radionuclide fallout has been used for the last several decades to quantify various soil and geomorphological processes and their rates, on different time scales. However, a basic assumption of the studies relying on these radionuclides is that they have a strong affinity for soil particles and that their mobility in soil solution and losses through leaching can be neglected. Another area of the scientific literature deals with the radionuclide mobility in soils as solute. In that context, the objective of this work is to determine the pedological conditions under which this hypothesis of poor solute mobility of radionuclides is valid. To this end, meteoric $^{10}$Be, $^{137}$Cs and $^{210}$Pb$_{xs}$ concentrations were measured in six soil profiles representative of 5 soil types contrasted in terms of physico-chemical properties: an Andosol and a Luvisol under pasture, a Ferralsol and a Leptosol under forest and a Podzol both under forest and cultivation. The main soil properties (soil pH, organic carbon (OC) content, particle size distribution and specific extractions) were measured. The