Impact of industries in the accumulation of radionuclides in the lower part of Ebro river (Catalonia, Spain)

摘要

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 Bi-214 and Pb-214 presented activity values of 105 +/- 43 Bq/kg and 100 +/- 8 Bq/kg, respectively.