Assessment of Natural Radioactivity Levels and Radiological Health Risks in Coastal Sediments of the Niger Delta, Nigeria: Environmental and Human Health Implications

Unregulated discharge of hydrocarbon-related wastes into Niger Delta coastal waters raises concerns over radionuclide contamination of sediments used in construction within the coastal region. Hence sediment samples were analyzed radiologically by means of Sodium iodide detector NaI (Tl). The mean concentration of 40K, 238U and 232Th that were analyzed are 1586.80, 27.25 and 46.90 Bq/kg respectively. The obtained values exceeded the world standard values of 400 and 30 Bq/kg for 40K and 232Th respectively while 238U is below standard value of 35 Bq/kg. The computed radiological indices with the view of ascertaining the sediment contamination level are radium equivalent activity, representative gamma index, the internal and external hazard index, absorbed gamma dose rate, annual effective dose equivalent and excess lifetime cancer risk with overall mean values of 216.50 Bqkg− 1, 1.70, 0.60, 0.65, 107.80 nGyh− 1, 0.13 mSvyr− 1 and ~4.6 × 10-3 respectively. These radiological indices exceeded respective recommended permissible limits. The research work concludes that unprofessional discharge of radiological contamination waste can lead to contamination of the coastal sediment being use for construction, and can further affect health of the residents in the region. However, these results can be use in the future as baseline for further radiological research.