Environ Monit Assess (2011) 173:29–35 DOI 10.1007/s10661-010-1367-x Natural radioactivity and chemical concentrations in Egyptian groundwater Rafat M. Amin · F. A. Khalil · M. A. K. El Fayoumi Received: 24 February 2009 / Accepted: 11 February 2010 / Published online: 11 March 2010 © Springer Science+Business Media B.V. 2010 Abstract Measurements of natural radioactivity in drinking water have been performed in many parts of the world, mostly for assessment of the doses and risk resulting from consuming water. A study of the radionuclide and chemical compo- nents in groundwater from Beni Suef Governate, Egypt has been carried out. Fifty water samples were analyzed by gamma ray spectroscopy to determine the 226 Ra, 232 Th, and 40 K concentra- tions; major elements, pH, alkalinity, and conduc- tivity were also measured. The specific activity values ranged from 0.008 to 0.040 Bq/l for 226 Ra, from 0.003 to 0.019 Bq/l for 232 Th, and from 0.025 to 0.344 Bq/l for 40 K. The annual inges- tions of these radionuclides, using local consump- tion rates (average over the whole population) of 1.5 l day −1 , were estimated to be 8.59, 4.86, and 83.47 Bq year −1 for 226 Ra, 232 Th, and 40 K, respectively. The estimated values and weighted means of these radionuclides compare well R. M. Amin (B ) · M. A. K. El Fayoumi Physics Department, Faculty of Science, Beni Suef University, Beni Suef, Egypt e-mail: rafatamin@yahoo.com F. A. Khalil Ionizing Radiation Laboratory, National Institute for Standards, Cairo, Egypt with the world average. The estimated effective doses from drinking water were found to be 2.4 μSv year −1 ( 226 Ra), 1.1 μSv year −1 ( 232 Th), and 0.51 μSv year −1 ( 40 K). Contribution of these ra- dionuclides to the committed effective dose from 1 year consumption of drinking water is estimated to be only 4%. Keywords Groundwater · Natural radioactivity · Dose assessment · Chemical contents · Beni Suef Introduction There is increasing concern worldwide about the quality of drinking water. Due to the importance of water for human life, its quality must be strictly controlled. For this reason, studies of groundwater for human consumption must be performed in order to guarantee that they have a low level of radioactivity. The earth contains numerous radio- active elements; their origin, for part of them, dates back to the formation of our world, while others are continuously produced through nuclear reactions in the universe. Among the former ele- ments, the most abundant are potassium-40 and the radioisotopes of the natural series of ura- nium and thorium including the parent nuclei 238 U and 232 Th and the decay products from the successive alpha or beta decays. The radionuclide