Natural radioactivity measurements and evaluation of radiological hazards in sediment of Oguta Lake, South East Nigeria

The distributions of naturally occurring radionuclides 226Ra, 232Th and 40K in sediments of Oguta Lake, Nigeria were determined using gamma ray spectrometry in order to assess the radiological health hazards and excess lifetime cancer risks associated with the use of the sediments. The mean activity concentrations of 226Ra, 232Th and 40K were found to be 47.89 ± 18.67 Bq kg−1, 55.37 ± 32.74 Bq kg−1 and 1023 ± 474 Bq kg−1, respectively. The results of the radiological indices and dose rates obtained in this study were all higher than their worldwide mean values but lower than their maximum recommended limits indicating that the use of the sediments as building materials do not constitute any excessive radiological hazards. The area is known to be subjected to environmental degradations due to oil exploration. Therefore, the results of this study could serve as an important radiometric baseline data upon which future epidemiological studies and environmental monitoring initiatives could be based.