222Rn determination in drinkable waters of a central eastern Italian area: comparison between liquid scintillation and gamma spectrometry

It is well known that the interest in radon concentration indoor as a pollutant emerged during the energy crisis of seventies which led to reduce ventilation in dwellings. Recently the Euratom Recommendation 2001/928 suggested the necessity of performing frequent 222Rn checks on tap waters. As a consequence of this Recommendation, Urbino and Perugia Universities carried out a preliminary 222Rn determination on tap waters of the Pesaro-Urbino province. Samplings were carried out in twenty-eight sites and radon concentration was determined by liquid scintillation counting and gamma-spectrometry. The results obtained by the two techniques were comparable (the deviation from the mean is lower than 10% for 54.5% of the samples). The resulted 222Rn concentration was very low (5 Bq-·11 for 43% of the samples) and, therefore, radon in waters cannot be considered as a direct radiological risk for the local population