Bio-geochemical behavior of ⁹⁰Sr and ¹³⁷Cs in tropical soil

¹ Instituto de Radioproteção e Dosimetria/CNEN, Av. Salvador Allende s /n°, Recreio, CEP: 22780-160, Rio de Janeiro, RJ. Brasil, e-mail: angelica@ird.gov.br
² Centro Nacional de Pesquisa de Solos/EMBRAPA, R. Jardim Botânico 1024, CEP:22460-000, Rio de Janeiro, Brasil
³ Programa de Pós-Graduação em Ciência Ambiental/UFF. Av. Litorânea s/n°, Boa Viagem, Niterói, RJ, 24210-340, Brazil

Abstract

In this work TF values for ⁹⁰Sr and ¹³⁷Cs were measured for reference plants grown in lysimeters containing soils representative of large agricultural areas in Brazil: Ferralsol, Nitisol and Acrisol. These results were discussed in the light of pedological analyses and results from the follow sequential chemical extraction protocol: 1) slightly acidic phase containing readily bioavailable elements; 2) easily reducible phase containing elements bound to Mn oxides; 3) oxidizable phase containing elements bound to labile organic matter; 4) alkaline phase containing mainly elements bound to Fe compounds; 5) resistant phase not potentially available to crops. These results showed that the main soil factors influencing the ¹³⁷Cs transfer to these soils were: exchangeable K, organic matter and iron oxides content. These results showed that ⁹⁰Sr plant uptake was influenced by exchangeable Ca. All these finds are in accord with previous studies and seems confirm the vulnerability of Ferralsol and Acrisol to ¹³⁷Cs contamination