“…The Specific Activity Ratio (SAR) is defined as the ratio between SA of OBT in the animal and SA of HTO in water. Previous work defined values of SAR and other transfer factors for different aquatic organisms from European rivers (Galeriu et al, 2009;Gontier and Siclet, 2011;Galeriu and Melintescu, 2010;Fontugneet al, 2005;Franco et al, 2006;Gleizon et al, 2009;Heling and Bezhenar, 2009;Howard et al, 2012;IAEA, 2008;Melintescu and Galeriu, 2011;Miyamoto et al, 2002). These values should not be used to tropical organisms without significant increasing in the uncertainty of model results.…”