Elemental and radiation attenuation parameter analyses to characterize a Cambisol from the Serra Dourada State Park, Brazil

摘要

The objective of this paper was to study the radiation interaction parameters and the degree of weathering of horizons of a Cambisol located in a conservation unit using the percentages of oxides. The oxide contents of the horizons were obtained by employing ED (energy dispersive) and WD (wavelength dispersive) X-ray fluorescence (XRF) techniques, considering that their interpretation of the weathering indices differs according to their resolution. The radiation interaction parameters were calculated using the XCOM computational code, which allowed us to obtain the following parameters: mu/rho (mass attenuation coefficient), sigma(A) and sigma(E) (atomic and electronic cross section), Z(eff) (effective atomic number) and N-el (electronic density). The results indicated that although both techniques proved to be efficient in detecting the levels of oxides, WDXRF was more sensitive. Fe2O3 showed great influence on the parameters mu/rho, sigma(A) and sigma(E), while Z(eff) and N-el presented no correlations. However, the curves of Z(eff) and N-el, in the studied energy range (1-100 keV), showed a better distinction between them when compared to the other parameters. The studied Cambisol presented a preserved structure, since it belongs to a conservation unit. Therefore, our findings should be considered a reference result for soils in the region with the same classification and origin, but which were subjected to anthropic action.