Scintillometric measurements were performed over an area of about 10.000 km2 in the calcareous region of Irecê (Bahia State, Brazil). Total gamma activity counting rates were found to be between 45 and 80 cps, with amean value of 50 cps, showing a rather homogeneous environmental total radioactivity. Seventy samples of rocks and soils were collected and their concentration of uranium, thorium and potassium were measured by laboratory gamma-ray spectrometry. At the same time iron and manganese rich concretions were sampled and studied, indicating strong correlation of MnO-U and Fe2O3-Th type. The results obtained were discussed from the point of view of the geochemical behavior of natural radioactive elements and correlated with previous data on underground waters of the region.
