Natural Radioactivity Levels and Estimation of Radiation Exposure in Environmental Soil Samples from Tulkarem Province-Palestine

Abstract

The activity concentrations of the natural radionuclides namely 238 U, 232 Th, 40 K and 137 Cs are measured for soil samples collected from different locations of Tulkarem district in West Back-Palestine. High-resolution gamma spectrometry (HPGe detector) was used to determine the activity concentration of these radionuclides in 72 surface soil samples taken from areas in and surrounding Tulkarem city. The concentration of 238U varied in the range 9.7 - 83.5 Bq kg –1 with an average value of 34.5 Bq kg –1 , 232Th in the range 5.3 - 44.8 Bq kg –1 with an average value of 23.8 Bq kg –1 , 40K in the range 10.2 - 404.0 Bq kg –1 with an average value of 120.0 Bq kg –1 and 137 Cs in the range 1.0 - 24.5 Bq kg –1 with an average value of 7.8 Bq kg –1 . The results have been compared with those of different countries of the world and Palestine. To assess the radiological hazard of the natural radioactivity, the absorbed dose rate (D r ), the radium equivalent activity (Ra eq ), the effective dose rate (E eff ), the annual effective dose equivalent (AEDE), Excess Lifetime Cancer Risk (ELCR), the radioactivity level index (I γ ), and the external (H ex ) and internal (H in ) hazard indices were calculated .It can be concluded that no risk may threat the residents around and center of Tulkarem city except some areas which activity due to fallout 137 Cs were high concentration levels. Hence the probability of occurrence of any of the health effects of radiation is low. Hence, measurements have been taken as representing baseline values of these radionuclides in the soil in studying area.