Radioactivity Concentrations and Their Radiological Significance in Sediments of Some Communities in Andoni, Rivers State, Nigeria

Quantification of naturally occurring radioactive materials in sediment provides information on geological characteristics, the possibility of petroleum and mineral exploration, radiation hazards to the dwelling populace and so on. The coastal sediment collected from the densely populated coastal area of Andoni, Rivers State Nigeria, were analyzed using a Sodium Iodide activated with thallium γ-ray spectrometer with low background radiation environment. The result showed an inhomogeneous distribution of radionuclides at different sampling points. The activity concentration of 226Ra ranges from 9.82±3.41 to 33.37±3.27 Bqkg-1 with an average value of 22.64 Bqkg-1 and 232Th ranges from BDL to 26.78 Bqkg-1 with the average value of 8.45 Bqkg-1. The activity concentration of 40K was relatively higher than 226Ra and 232Th, ranging from 7.35±3.03 to 75.38±2.75 Bqkg-1 with an average value of 29.01 Bqkg-1. The average mass concentration of 226Ra, 232Th and 40K in the sediments were found to be 2.04 ±0.002, 2.08 ±0.001 ppm and 0.09± 0.003 % respectively. The 232Th/226Ra ratio was found to be within the range of 0.00 to 3.59 with a mean value of 1.02 which is far below the continental crustal average concentration of 3.82. There was also a poor correlation of radionuclides in the sediment showing differences in their origin. The mean values of AGED, D, AEDE, Hex, Raeq, RLI, Iα, AUI and ELCR were below their recommended values. Thus the radioactivity levels in the studied sediments are generally of very little radiological concern for human health.