Paper Title
Distribution of Natural Radionuclides in the Surface Soil of Eastern Province, Saudi Arabia

The activity concentrations of natural radionuclides 238U, 232Th and 40K in surface soil samples from Eastern Province, Dammam city, Saudi Arabia were measured by gamma spectrometry using (HPGe) detector. The activity concentration average values of the radionuclides 226Ra, 232Th and 40K in the soil samples ranged from 11.85 – 30.43, 5.74- 15.97 and 362-469 Bqkg-1, respectively. with overall mean values of 16.73, 10.40 and 419.99 Bq kg-1 respectively. These values are within the world average. The mean value radium equivalent activity value was 63.93Bqkg-1, lower the international limit 370Bqkg-1. The Representative level index (Iɣ), internal and external hazard index (Hin, Hex) of all samples under study were less than the limit of unity. The absorbed dose rate due to three primordial radionuclides lies in the range of 24.23 – 39.48 nGyh-1 with a mean of 31.68 nGyh-1, which yields an annual effective dose of 0.039 mSvy-1.The mean value of Excess lifetime cancer risk was calculated as 0.14 x 10-3 which is below the World average (0.29 x 10-3). The results obtained in this study are lower than the world recommended values and are found to be safe for the public and environment. The baseline data of this type will almost certainly be important in making estimates of exposure to populations. Keywords - Soil- Gamma Dose- Radioactivity - Lifetime Cancer Risk