en Radiation Biology Radiation Biology تحقيق بديع Original Research <div style="text-align: justify;">Background: Ondo city in Ondo State Nigeria includes Ondo East and West could be described as a research city due to antecedent number of research institutes. Materials and Methods: Dose due to radioactivity content of soil samples from sixteen waste dump sites in Ondo, Southwestern Nigeria was determined using gamma-ray spectrometer in order to evaluate the radiation hazard health profile and excess lifetime cancer risk ELCR. Results: The weighted average value of radon emanation coefficient, mass exhalation rate, concentration in soil gas and surface exhalation rate were 10.5%, 15.2 &micro;Bq kg^-1 s^-1, 2.2 kBq m^-3 and 18.8 mBq m^-1s^-1. The weighted mean concentrations obtained were 354 &plusmn; 53, 58&plusmn;14 and 23 &plusmn; 2Bq kg^-1 for ⁴⁰K, ²²⁶Ra and ²³²Th respectively. Radium equivalent activity (119.11Bq kg^-1), Outdoor external dose (54.26 nGy h^-1), Indoor external dose (107.04 nGy h^-1), and total average annual effective dose (0.59 mSv y^-1) were obtained. From the measured &gamma;-rays spectra, elemental concentrations were determined for ²³²Th (mean 5.8ppm), ²²⁶Ra (mean 4.8ppm) and ⁴⁰K (mean 1.1 %). Thorium was lower than world average 7.4ppm by a factor of 1.3; radium was higher than the world average (2.8 ppm) by factor 1.7 while potassium was relatively equal to world average (1.3 %). Conclusion: The total excess lifetime cancer risk ELCR was found to be 1.95 x 10^-3which was slightly higher than the world average. In addition, a good correlation was found between the radium concentration and radon exhalation rate in the area.</div> Activity concentration, dose, dumpsites, excess lifetime cancer risk ELCR, radon parameters. 379 390 http://ijrr.com/browse.php?a_code=A-10-1-794&slc_lang=en&sid=1 E.B. Faweya febdeprof@yahoo.co.uk 7900319475328460014260 7900319475328460014260 Yes Department of Physics, Faculty of Science, Ekiti State University, Nigeria G.O. Olowomofe 7900319475328460014261 7900319475328460014261 No Department of Physics, Faculty of Science, Ekiti State University, Nigeria H.T. Akande 7900319475328460014262 7900319475328460014262 No Department of Physics, Faculty of Science, Ekiti State University, Nigeria O. Faweya 7900319475328460014263 7900319475328460014263 No Department of Statistics, Faculty of Science, Ekiti State University, Nigeria G.E. Adesakin 7900319475328460014264 7900319475328460014264 No Department of Physics, Faculty of Science, Ekiti State University, Nigeria