Health Detriment Associated with Exposure to Natural Radioactivity from the Soil of Ondo and Ekiti States South Western, Nigeria

The health detriment associated with human exposure to primordial radionuclides from the earth crust has been a major source of concern to public health observers across the globe. The level of such detriment can be mitigated by continuous monitoring in order to ascertain that the safe threshold is maintained from time to time. In the light of the above, the activity concentrations of naturally occurring radioactivity (i.e 232Th, 226Ra and 40K) were determined in seventeen soil samples collected from selected cities across Ondo and Ekiti States using gamma ray spectrometry. The measured activity concentrations ranged from 31.93±1.77 to 227.50±4.43 Bq Kg-1 for 232Th, 45.60±2.99 to 210.36±8.76 Bq Kg-1 for 226Ra, 364.89±6.40 to 1274.57±12.48 Bq Kg-1 for 40K, and 48.64±2.04 to 207.22±5.50 Bq Kg-1 for 232Th, 73.52±3.81 to 209.15±7.45 Bq Kg-1 for 226Ra, 542.26±10.41 to 2348.86±21.83 Bq Kg-1 for 40K for Ondo and Ekiti States, respectively. Absorbed dose was calculated using the measured activity concentrations. The mean absorbed dose rate and standard deviation in nGy h-1 were 140.89±65.27 and 173.27±85.40 for Ondo and Ekiti States, respectively. These results are beyond the limits (30 nGy h-1-70 nGy h-1) recommended by UNSCEAR, 1988 for area of normal background radiation. Health detriment to various organs of the body resulting from the exposure scenario was evaluated.