Asian Basic and Applied Research Journal

Quest for knowledge concerning radioisotopes in sand as a building material has become necessary due to high level of maritime activities, anthropological activities, incessant dumping of waste in the river from which the sands are dredged. The aim of this study was to ascertain level of radiation pollution emanating from radionuclides of natural origin and that from human enhancement or artificial sources in the sands through spatial distribution of 226Ra, 232Th and 40K. A digilert nuclear radiation monitoring meter was used to measure the background ionizing radiation (BIR) at the dump sites and a global positioning system was used to record the coordinates at each point of measurement. Four sand dumps were investigated using the results of forty BIR readings taken in situ in a total of forty sampled points. Results of exposure levels ranged from 0.011 to 0.028 mRhr^-1 with mean value of 0.020 mRhr^-1. Health indices were computed from the above results. Hence, absorbed dose rate, annual effective dose equivalent and excess lifetime cancer risk were calculated to be 170.7 nGyhr^-1, 0.21 µSvy^-1 and 0.74 x 10^-3 respectively, clearly exceeding their respective permissible limits of 0.013 mRhr^-1, 84 nGyh^-1, 70µSvy^-1 and 0.29 x 10^-3. These elevations should be further investigated using Sodium Iodide Spectrometry or high powered Germanium Detector to confirm suitability of these sands from this locations as building material.