The determination of actinides in small concentrations of natural 232 Th, 238 U, 226 Ra and 210 Po in environmental samples has been the subject of several in vestigations (Hao etal.,2011). In drinkable water supplies ,the measurement of these naturally occurring radionuclides is important for environmental pollution and public health studies. Findings have suggested that the source of the radionuclides dissolved in the water is the surrounding bedrock; in geological settings rich in 238 U, like, for example, granite, also higher activity concentrations of the uranium series of radionuclides like 226 Ra and 222 Rn are expected (Wallnerand Steininger,2007).