Assessment of tritium distribution in rain, surface and drinking water in Portugal during 2006–2017 period

Water samples from different origins (rain, surface and drinking) collected in Portugal during the years 2006 to 2017 were analyzed for the tritium ( 3 H) activity contents using isotopic enrichment followed by liquid scintillation counting. Regarding rainwater, the results show no significant correlation between the normalized 3 H and the precipitation amount and no variations among the annual seasons. The higher 3 H values observed for Tejo River indicate the influence of the Almaraz NPP located in Spain. The 3 H activity levels in drinking water were one to two orders of magnitude lower than the European parametric value (100 Bq L −1 ).