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Polonium-210 is analysed in different samples which can be affected by the presence of a dicalcium phosphate plant (DCP). Particularly, it was determined in sludge samples from a drinking water treatment plant located downstream of the phosphate plant. From the obtained results, it was not possible to establish a correlation with the industrial activities carried out in the DCP plant since the measured activities were comparable to the reported in the literature for normal soils. This isotope was also monitored in different biota species (as mussels) taken also downstream of the DCP, and the potential risk of their ingestion by calculating the total effective doses was evaluated. As a result, it is important to highlight that the ingestion of these mussels does not constitute a risk for the population since the found doses were lower than the values published by UNSCEAR.

Po, Pb,U, U,Th and Th were analysed in the edible part of four different species of bivalves typically produced and consumed in the Ebro Delta area. The results show that the main contributor to the radioactive content in these species wasPo, with values ranging between 263.1 ± 26.6 and 813.0 ± 72.9 Bq/kg (d.w.), which are higher than the usual reported activity levels in other geographical areas. This can probably be attributed to the activities of a phosphate industrial plant located upstream on the Ebro River, which may lead to enhanced levels of naturally occurring radioactive isotopes in the aquatic ecosystem. To determine the possible impact on health, the committed effective doses through the consumption of the different species were evaluated and the cumulative total annual effective dose for their consumption was estimated to 187.6 μSv/year, which is in the range of 200-1000 μSv/year given by UNSCEAR.

A method has been developed for the determination of two artificial beta emitters ( 55 Fe and 63 Ni) in sludge samples from a drinking water treatment plant (DWTP). The activities found for 55 Fe and 63 Ni ranged between (\15 Bq kg -1 ) and 162 Bq kg -1 , and between (\10 Bq kg -1 ) and 65 Bq kg -1 , respectively. Using the sludge activities is possible to estimate the activity of both radionuclides in the river water, based on the relation between the amount of sludge generated and the flow of the river water treated in the plant. Based on this estimation, it is possible avoid the use of time-consuming methods.