Radioactivity measurements and radiation dose evaluation in tap waters of Central Italy.

Consumption of drinking water is very important for human nutrition and its quality must be strictly controlled. A study of radioactivity content in tap water samples collected in the Central Italy was performed in order to check the compliance with recent European regulations. Gross alpha and beta activity, 226Ra, 238U and 234U concentrations were measured. Gross alpha and beta activities were determined by standard ISO 9696 and ISO 9697; for 226Ra determination liquid scintillation was used. 238U and 234U concentrations were determined by alpha spectrometry after separation from matrix by extraction chromatography and electroplating. Recommended WHO guideline activity concentrations for drinking water (0.1 and 1.0 Bq/L for gross alpha and gross beta activity, respectively) are exceeded in two cases for gross alpha activity and are not exceeded in any case for gross beta activity. The concentrations (mBq/L) of 226Ra, 238U and 234U ranged from <1.70 to 15.3, 0.65 to 48.8 and 0.780 to 51.5, respectively. Effective dose due to the uranium isotopes and radium was calculated for children and adults using the dose coefficients reported by EC Directive 96/29 EURATOM and annual water intake. For all class ages, the doses are quite similar and much lower than 0.1 mSv/year.