Health risk assessment and statistical analysis of natural radioactivity in the uranium exploration area of Zabili, Chad

The activity concentrations of natural radionuclides 226 Ra, 232 Th and 40 K in nineteen soil samples from Zabili uranium exploration area were measured using a low-background digital gamma-ray spectrometer equipped with broad energy germanium detector. The activity concentrations of 238 U, 232 Th, and 40 K range from 16.5 to 1110.9 Bq.kg -1 , 19.45 to 76.97 Bq.kg - 1 , and 3.28 to 839.5Bq.kg -1 , with their mean values of 478.0, 58.9