Articulo
Hyperfine and radiological characterization of soils of the province of Buenos Aires, Argentina
Autor
Montes, María Luciana
Taylor, Marcela Andrea
Mercader, Roberto C.
Sives, Flavio Rubén
Desimoni, Judith
Institución
Resumen
The depth profile concentration of both natural and anthropogenic gamma-ray-emitter nuclides were determined in soil samples collected in an area located at 34° 54.452′ S, 58° 8.365′ W, down to 50 cm in depth, using an hyper-pure Ge spectrometer. The soil samples were also characterized by means of Mössbauer spectrometry and X-ray diffraction. The activities of <SUP>238</SUP>U and <SUP>232</SUP>Th natural chains remain constant in depth at 41 Bq/kg and 46 Bq/kg, respectively, while the <SUP>40</SUP>K activity increases from 531 Bq/kg to 618 Bq/kg between 2.5 cm y 25.5 cm of depth. The only anthropogenic detected nuclide is <SUP>137</SUP>Cs, whose activity changes form 1.4 Bq/kg to values lower than the detection limit (L<SUB>D</SUB>) for depths below 25 cm, exhibiting a maximum at 10 cm beneath the surface. The Mössbauer spectra show two magnetic sextets associated with α-Fe<SUB>2</SUB>O<SUB>3</SUB> and Fe<SUB>3</SUB>O<SUB>4</SUB>, as well as two Fe<SUP>+3</SUP> Fe<SUP>+2</SUP> doublets, probably originated in octahedral and tetrahedral sites of paramagnetic phases. The Fe<SUP>3+</SUP> paramagnetic signal relative fraction increases up to 82% at the expense of the α-Fe<SUB>2</SUB>O<SUB>3</SUB> one when de depth increases. No correlation between Fe<SUB>3</SUB>O<SUB>4</SUB> and the <SUP>137</SUP>Cs was identificated. Facultad de Ciencias Exactas Instituto de Física La Plata