137CS Activity Profiles in Soil of the Province of Buenos Aires, Argentina

M. L. MONTES; R. C. MERCADER; L. M. S. SILVA; C. S. A. SÁ; M. A. TAYLOR; J. RUNCO; J. DESIMONI

Salamanca

Congreso; 1st International Congress on Water, Waste and Energy Management; 2012

The fallout of radioactive debris originating in the Southern Hemisphere atmospheric nuclear weapons has polluted the Southern soils with long live radionuclides, like 137Cs. The principal factors that affect migration this nuclide in the soil are pH, organic matter content, textural class, mineralogy and concentration of radionuclides in the soil-liquid phase, among others. We present here, activities depth profiles down to 50 cm of the 137Cs of unperturbed soil of the neighbourhood of La Plata city, together with pH, texture and organic carbon content of soils. The dimensional convection-dispersion equation with constant parameters is the most used approach to estimate the 137Cs transport parameters, however, it does not reproduce all the 137Cs profiles. The convection-dispersion-fixation model was used, instead. The determined mean average value of 137Cs inventory was 891 ± 220 Bq m-2. Differences in depth distributions were detected attributed principally to the clay and illite content. Not all the 137Cs soil profiles can be reproduced by the convection-dispersion with constant parameters, probably due to predominance of illite phase in the studied soils, which is a known receptor of cesium in a irreversibly way.