Contenido y distribucción de los metales pesados en suelos de Navarra. Cadmio, cobre, manganeso, niquel, plomo y cinc

Contents of Cd, Cu, Mn, Ni, Pb and Zn were analyzed in A and C horizonts from 154 samples representative of the soils of Navarra (Spain). In both horizonts acidic digestion (HNO3, HCl04, HF, HCl) was realized to measure heavy metal"s total content, and in the A horizont DTPA extraction was made. The metals of all samples were determined with ICP-AES. Maps of distribution were elaborated after a kriging interpolation. The results of this statistic transformation were represented with a G.I.S. (IDRISI). Also accumulated frecuency diagrarns were use to estimate the diferent populations of each element (included background population) and their concentration thresholds.

The mean values of the six elements studied are similar to those from Spain and other European countries found in literature. Comparing to World mean values, Cd and Pb are three times higher, probably due to atmospheric deposition. However, Mn values are below the World mean, but at the same level of European countries.

The parent materials are the source of the other elements. In some areas the values of those concentratitons are near the critical values