Assessment of Natural Radionuclides Level in Wasteland Soils around Olusosun Dumpsite Lagos, Nigeria

Abstract

The natural radionuclide level in wasteland soil around Olusosun dumpsite Ojota, Nigeria were measured using a highly shielded Canberra Na(Tl) detector, a type of gamma-ray spectrometer. A total of 30 samples (15 from active site and 15 from dormant site) were analyzed. The mean value of 238 U, 232 Th and 40 K concentrations determined for soil samples from the active dumpsite were 69.69 ± 19.10 Bqkg-1 , 14.49 ± 3.22 Bqkg-1 and 409.44 ± 86.08 Bqkg-1 respectively. For the soil samples from the dormant dumpsite, the mean value of 238 U, 232 Th and 40 K concentrations were 61.25 ± 21.82 Bqkg-1 , 12.08 ± 1.74 Bqkg-1 and 345.98 ± 56.92 Bqkg-1 respectively. The mean value of 238 U, 232 Th and 40 K concentrations for soil samples from both the active and dormant dumpsites were higher than the permissible global values of 52.2 Bqkg-1 , 41.0 Bqkg-1 and 230.0 Bqkg-1 respectively by UNSCEAR. The mean annual effective dose obtained for soil sample from active dumpsite is 0.2767 while 0.2550 was obtained for soil samples from the dormant dumpsites. Both were found to be below the recommended standard by UNSCEAR. All the soil samples analyzed for both the active and dormant dumpsites met the safety criteria by UNSCEAR and hence do not pose any radiological hazards to human health. However, the result of statistical analysis (ANOVA) showed that there is significant difference between the result of the annual effective dose for the active soil samples and the dormant soil samples