Ebro River extends over almost 930 km and is the main Spanish river entering the
Mediterranean Sea. There are several industries located along this river course including
a dicalcium phosphate factory (DCP) and two nuclear power reactors. These installations,
together with other factors such as the geology, can contribute to the radiological
content of the river. Therefore, this study was performed to determine some natural and
also some anthropogenic radionuclide concentrations in the Ebro River ecosystem. We
analysed water samples, solid samples (rice field sludge and surface marine sediment
samples), and also biota samples (Cladophora glomerata and
Cynodon dactylon). For water samples, gross alpha, gross beta, tritium,
uranium, thorium and also a group of gamma-emitting isotopes’ activities were determined.
The main contribution to radioactivity for these samples was due to some isotopes from the
uranium and thorium chain. For the solid samples, we quantified some natural and
artificial gamma radioisotopes, which may be related to the geological and/or industrial
activities located in this zone. In the case of biota, the results indicate that the
presence of the DCP has a significant influence, since the highest activity was observed
in the surroundings of this industry (Flix), where isotopes such as 214Bi and
214Pb presented activity values of 105 ± 43 Bq/kg and 100 ± 58 Bq/kg,
respectively.