EVALUATION OF NATURAL RADIONUCLIDES AND RADIATION HAZARDS OF WATER AND FLOODPLAIN SOILS OF ALATO RIVER USING GAMMA RAY SPECTROMETRY
Authors: Olayinka Abidemi Ibigbami, Gloria Irenosen Akinola and Samuel Sunday Asaolu
Olayinka Abidemi Ibigbami: Department of Chemistry, Ekiti State University, PMB 5363 Ado-Ekiti, Nigeria.
Gloria Irenosen Akinola: Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University, Awka, Nigeria.
Samuel Sunday Asaolu: Department of Chemistry and Biochemistry, Islamic University in Uganda, Mbale, Uganda.
ABSTRACT
Natural radioactive elements can pose health risks if present in elevated concentrations. These elements can adversely affect aquatic and terrestrial ecosystems. This study evaluates the specific activity of radionuclides in floodplain soil and water samples collected from Alato river in South western Nigeria. The samples were analysed for activity concentration of 40K, 235U and 232Th using NaI (TI) detector gamma ray spectrometry system. The mean activity concentration of radionuclides in soil samples were: 235U: 8.65±01.85 to 9.74±0.45 Bq/kg, 232Th: 35.58±1.79 to 48.53±2.28Bq/kg, 40K: 471.84±5.33 to 593.59±5.47 Bq/kg, while that of water samples; 235U: 8.71±1.02 to 9.57±0.07 Bq/l, 232Th: 29.60±1.71 to 35.58±1.79 Bq/l and 40K: 433.86±8.86 to 593.82±7.22 Bq/l. The average activity concentration of 235U in both matrixes were lower than the global average, while those of 40K were higher than guidance level of the World Health Organization (WHO). The average activity concentration of 232Th in the soil samples differ at different regions which were be higher or lower than the global average, while the level in water was within tolerable range. The study revealed that the mean value of absorbed dose rate is lower than the world average limit. It is clear that the external and internal hazard associated with the soil usage in this location do not pose some radiological risk.
Keywords: Floodplain, Radionuclides, Gamma Spectrometry, Radiological Risk, Specific Activity