Abstract: The activity concentrations of natural radionuclides of the elements (40K, 238U and 232Th), collected from Kutha district of Babylon governorate are studied and evaluated. Twenty soil samples with (0-15) cm in depth are collected. Gamma spectrometer NaI (TI) source is used for calibration. The radioactivities of natural isotopes K-40, U-238 and Th-232, were assessed. These studies show that radio activities of isotopes are acceptable according to the standard levels. Also, the activity of radium equivalent, the rate of annual effective dose, average air volume and external risk index are evaluated. The results are found within the internationally tolerable values. The results show that the mean of the radioactivity of 238U is (19.1565)Bq / kg, while it is (54.501) Bq/kg for 232Th and (179.578) Bq/kg for 40K. The study results showed that the average of radiological effects, like the Radium equivalent (Raeq), the rate of absorbed dose (Dr), the index of external hazard (Hex), the index of internal hazard (Hin), the index of representative gamma hazard (Iγ), the Annual Effective Dose Equivalent (AEDE) and the Excess Lifetime Cancer Risk (ELCR) are as follow: 110.920 Bq/kg, 50.1838 nGy/h, 0.29953, 59.1530, 27.996, 0.34 mSv/y and 1.268x10-3, respectively.
Keywords: Natural radioactivity, Absorption, External hazard, Effective annual dose, Excess lifetime cancer risk.