Impact of the geological substrate on the radiological content of Galician waters

Galicia (NW of Spain) is home to a highly-fractured soil rich in 238U minerals, being the widest radon-prone area of the Iberian Peninsula. High precipitation levels confer a rich variety and abundance of both surface and groundwaters, which are extensively used for human consumption. Nevertheless, there exists no comprehensive body of information about the impact of the high environmental radioactivity on the radiological content of Galician waters. Measurements of 222Rn, gross alpha/beta, 226, 224Ra and 3H activity were undertaken over a significant range of traditional springs, waters for spas and bottling plant wells. A seasonal survey was also performed for five network water suppliers to the largest Galician cities. The main outcome of this study has been the determination of statistical correlations between the water's radiological content and different environmental factors. Water measured at bottling plants reveal radiological values exceeding the U.E. limits, however this is eliminated in the industrial bottling process before reaching the consumer. Neither significant values nor seasonal variations were obtained for network waters.

► Radiological survey of waters in an important prone area of the Iberian Peninsula.
► U.E. action limits exceeded, especially on waters intended for bottling.
► No significant levels on networks and bottled water after processing.
► 238U and 232Th chain descendants contribution depends on the water type.
► Correlations between radiological content and environmental gamma exposure rate.