Corresponding author: topazgemss@yahoo.com DOI: 10.21608/ajnsa.2019.3489.1081 © Scientific Information, Documentation and Publishing Office (SIDPO)-EAEA Arab J. Nucl. Sci. Appl., Vol. 52, 2, 62-71 (2019) Estimation of Radiation Hazards of Natural Radionuclides in Archaeological Site (Tanis), Egypt Nabil M. Hassan (1,2) , N. A. Mansour (1) , Safwat Salama (3) ,and Ahmed Al-deeb (1) (1) Department of Physics, Faculty of Science, Zagazig University, Zagazig, Egypt (2) Department of Natural Radiation Safety, Korea Institute of Nuclear Safety 62, Gwahak-ro, Yuseong-gu, Daejeon 34142, Republic of Korea (3) Radiation Protection & Civil Defense, Nuclear Research Center, Egyptian Atomic Energy Authority, Egypt Natural radionuclides of 238 U ( 226 Ra), 232 Th and 40 K contained in the earth crust (soil) of Archaeological Site (Tanis, San Al-Hagar, Sharqai, Egypt) were measured using γ-ray spectroscopy system equipped with High pure germanium detector (HPGe). 20 soil samples were collected from the ground surface of tomb rooms, roads among tombs and the outer empty space of Tanis. Arithmetic mean values of radionuclides concentrations in the studied samples were 5.96 ± 1.46 Bq kg -1 for 226 Ra, 3.78 ± 1.60 Bq kg - 1 for 232 Th and 70.34 ± 7.20 Bq kg -1 for 40 K, respectively. All the studied natural radionuclides had concentration values less than worldwide recommended value of 35, 30, 400 Bq kg -1 for 226 Ra, 232 Th and 40 K, respectively. Furthermore, the radiation dose in that site was measured using Digilert100 radiation survey meter and its mean value was of 0.52 ± 0.13 μSv h -1 which is much lower than safety limit. Moreover, radiological hazards indices of radium equivalent activity (Ra eq ), external (H ex ) and internal hazard indices (H in ), alpha and gamma radiation indices and annual effective dose due to the presence of those radionuclides were calculated and their values were less than worldwide limit. These results implied that the Tourists can safely visit and stay in this site (San Al-Hagar) as long as they wish. Keywords: Natural radionuclides, HPGe, hazard indices, Radiation dose, Soil, Archaeological site, Egypt Introduction Human beings are exposed to ionized radiation emitted from natural radionuclides in the earth’s crust, rocks, and soils which resulted from the weathering of the different type of rocks. The level of those radionuclides varied according to the type of rocks. Igneous rocks contained high levels of radinuclides while sedimentary rocks contained low levels. The soil (upper layer of the earth’s crust) is one of the most important sources of naturally occurring radioactive materials (NORM), i.e. uranium series, thorium series and potassium [1-4]. UNSCEAR, 2000 [5] reported that the main contributor of human beings’ exposure comes from natural radiation, and the worldwide average annual effective dose is 2.4 mSv. Thus, the high level of ionizing radiation above the earth is mainly due to the increase of the concentration of natural radionuclides of uranium ( 238 U), thorium ( 232 Th), their daughter products and potassium ( 40 K), NORM, in earth’s crust, rock and soil [6]. Hence, the evaluation of natural radionuclides concentrations is very important from the point of view of environmental radiation protection. The radiological implications of those radionuclides are the result of γ-ray exposure of the human body and irradiated of its inter tissue (lung, stomach, bone marrow, …) by the inhalation or digestion of radon and its progenies [7]. Consequently, the most important sources of external and internal exposure are the gamma radiation and alpha particles emitted from uranium ( 238 U) series, thorium ( 232 Th) series and 40 K present ISSN 1110-0451 (ESNSA) Web site: ajnsa.journals.ekb.eg Arab Journal of Nuclear Sciences and Applications Received 11 th Apr. 2018 Accepted 24 th Feb. 2019