137Cs activity concentration in soil of Alagoas State, Brazil.

Cesium 137 is present in worldwide. To evaluate its deposition in the Brazilian state of Alagoas a total of 41 samples were collected by the Geological Survey of Brazil, then processed and analyzed by gamma-ray spectrometry with hyperpure germanium detectors. The activity concentration varied from (0.3 ± 0.1) Bq/kg to (1.1 ± 0.4) Bq/kg. The present study shows that the Borborema Plateau acts as a natural barrier to rainfall, favoring the deposition of 137Cs on the local soil. • Soil samples were collected in the first 25 cm from the surface. • Cs-137 activity concentrations ranged from 0.3 to 1.1 Bq/kg, with an geometric mean of 0.53 Bq/kg. • Most samples containing 137Cs were found in the rainiest region of the state. [ABSTRACT FROM AUTHOR]