To evaluate the extension of soil pollution of a site it is common to compare the contents found in a specific soil with those in natural conditions (unpolluted) or with reference values (patterns). The goal of this study was to propose: 1) reference values (VR) and tolerance limits for the most representative Brazilian soils, and 2) a model for obtaining the levels of Cd, Co, Cr, Cu, Ni, Pb and Zn in a soil under natural conditions from the silt, clay, Mn, Fe contents and CEC value. A set of 256 soil samples was formed by similarity in seven groups and the concentrations corresponding to the upper quartile of the data were calculated. These concentrations are proposed as the reference values (VR) in Brazilian soils. Besides, tolerance limits admitted for each group were taken as antilog (m + 2s), where m (average) and s (standard deviation) were transformed to log10. The classification functions of the discriminant analysis proved to be appropriate to allocate new samples in the established groups. Thus, it is possible to evaluate soils under anthropogenic activity and to know if there is a reason for suspecting of pollution of the site.
soil pollution; baselines levels; metal levels; metals in soil
