Inventory and vertical migration of 90Sr fallout and 137Cs/90Sr ratio in Spanish mainland soils

In this paper the inventory of Sr-90 in 34 points distributed along the Spanish peninsular territory is presented. Obtained values range between 173 Bq/m(2) and 2047 Bq/m(2). From these data set and those Cs-137 data obtained in a previous work the Cs-137/Sr-90 activity ratio has been established, laying this value between 0.9 and 3.6. Also the migration depth of both radionuclides has been analysed obtaining for Cs-137 an average value 57% lower than that obtained for Sr-90. Additionally, this paper presents the results obtained in 11 sampling points in which the activity vertical profile has been measured. These profiles have been analysed to state the behaviour of strontium in soils and after, by using a convective diffusive model, the parameters of the model which governs the vertical migration of Sr-90 in the soil, v (apparent convection velocity) and D (apparent diffusion coefficient) have been evaluated. Mean values obtained are 0.20 cm/year and 3.67 cm(2)/year, respectively. (C) 2011 Elsevier Ltd. All rights reserved.