Vol. 8, Issue 6, Part G (2022)

Abstract
Background: Mining activities of coal have the capacity to raise the level of natural radionuclide concentration in our environment. This exposes human population to ionizing radiations with their associated health hazards. This study was aimed at measuring natural radionuclide concentration of ²²⁶Ra, ²³²Th and ⁴⁰K, and their associated health hazard indices in coal samples from Okobo coal mine. Materials and Methods: The survey design adopted for this study was the cross sectional type. Coal samples totaling ten (10) in number, were randomly collected from the coal mine. The sampled coal was analyzed at the University of Ibadan, in the laboratory of the National Institute of Radiation Protection and Research (NIRPR), using high resolution spectrometry technique, with high purity germanium (HPGe) detectors. Results: The obtained results revealed that the radionucide concentration of ²²⁶Ra in the sampled coal recorded slightly higher value (21.34±7.94 Bq/kg) than global average of 20 Bq/Kg. However, the recorded values for ²³²Th (13.61±5.08 Bq/kg) and ⁴⁰K (20.91±15.77 Bq/kg) fall below the global average value of 20 and 50 Bq/Kg respectively. All calculated radiological hazard parameters recorded lower values than the global permissible value but for annual gonadal dose equivalent (AGDE) which recorded significantly higher value (407.74 mSv/yr) than the world acceptable limit of 300 mSv/yr. Conclusion: The activity concentration of ²²⁶Ra for Okobo coal sample recorded a unit mean value higher than the global average, however the recorded values for ²³²Th and ⁴⁰K fall below global permissible values. All radiological health hazards recorded lower values than the precautionary safe limit but for annual gonadal equivalent dose which recorded significantly higher value than the global permissible limit. This implies that both staff and residents of the community could be exposed to radiological threat, which might affect the functionality of their sensitive organs if prolonged and cumulative exposure is not avoided.