Résumé
The γ radiation exposure due to radioactivity concentration of 40K, 238U and 232Th in soil samples from 250 different locations from 40 communities in the oil – producing region of Nigeria was carried out. The radioactivity concentrations of these radionuclides were used to determine the absorbed dose, annual effective dose equivalent, the health hazard indices and cancer risk using standard analytical methods. The range of values for the absorbed dose are 6.97 nGyh-1 to 33.29 nGyh-1, annual effective dose equivalent (outdoor) are 8.55 μSvy-1 to 40.83 μSvy-1 and (indoor) are 34.19 μSvy-1 to 163.36 μSvy-1. The external hazard index ranges from 0.038 to 0.174 while the internal health hazard index is from 0.045 to 0.191. The cancer risk obtained for the communities ranges from 0.030 x 10-3 to 0.143 x 10-3. All these values are below the standard limits when compared to the world permissible United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR) values for such environment. This shows that the exploration and exportation of crude oil in Nigeria did not pose a radioactive health hazard to the oil producing communities.