In situ gamma spectrometry of terrestrial naturally occurring radioactive materials and radiation hazard assessment of Kebbi State, Nigeria

Environmental monitoring was performed in order to measure the activity concentrations of U-238, Th-232 and K-40. In situ gamma spectrometric measurements of 421 different locations were carried out based on geological formations using a portable gamma-surveyor designed according to IAEA methodology. The average activity concentrations were 38 ± 21, 33 ± 18 and 327 ± 197 Bq/kg for U-238, Th-232 and K-40, respectively. The average activity concentration of U-238 was above the UNSCEAR world average value. The average ELCR was above the UNSCEAR and USEPA permissible maximum values implying enhanced cancer potential risk in Kebbi state.