Radioactivity evaluation of Ebro river water and sludge treated in a potable water treatment plant located in the South of Catalonia (Spain)

A potable water treatment plant with an average production rate of 4.3 m3/s, providing several cities in the south of Catalonia (Spain) with drinking water, has been studied for a period of six years (2002–2007) regarding its capacity to remove several natural and anthropogenic radionuclides. First, gross alpha, gross beta and tritium activities were determined in ingoing and outgoing water samples. The values for all these parameters were below the Spanish normative limits established for waters for human consumption. For the sludge samples generated in the plant, we quantified some gamma emitting radioisotopes: natural (40K, 214Pb, etc.) and artificial (60Co, 110mAg, etc.) which may be related to the geological or/and industrial activities (such as a nuclear power plant) located upstream of the PWTP on the Ebro River. Finally, when the sludge samples were compared with those from other water treatment plants, the influence of the industrial activities on the radioisotopes found in the analysed samples was confirmed since the activity levels for some of the isotopes quantified were 10 times higher.