Abstract

The radiological assessment of soils from two dumpsites in Southwestern Nigeria was carried out to determine the level of human exposure in the area. A total of 15 representative samples were randomly collected around the perimeter of each dumpsite and the samples were analyzed using a 2.0 by 2.0 cm NaI(Tl) gamma-ray spectrometric detector manufactured by ORTEC. The mean activity concentrations of radionuclides in the soil from Saje dumpsite were 172.84±121.16 Bq/kg for 40K, 32.71±16.33 Bq/kg for 226Ra and 48.72±22.26 Bq/kg for 232Th while from Ilaro dumpsite, themean activity concentrations were 195.04±75.45 Bq/Kg for 40K 61.33±16.86 Bq/kgfor 226Ra and 75.84±33.31 Bq/kg for 232Th. The respective mean gamma and effective dose rates were 53.65±19.04 nGy/h and 0.066±0.023 mSv/y for Saje dumpsite and 84.78±27.87 nGy/h and 0.104±0.034 mSv/y. The outdoor gamma dose, outdoor effective dose, and the cancer risk due to ionizing radiation exposure from Saje were lower than the values obtained for Ilaro. The difference in the radioactivity levels from the two dumpsites may be attributed to the composition of refuse in the dumpsites. The results showed that the radioactivity levels from the two dumpsites were lower than the world average values recommended by UNSCEAR. Therefore no serious radiological hazard is expected on the populace living around the dumpsites