Comparative Assessment of Radioactivity Concentration in Sweet Potatoes from Different Geopolitical Zones of Nigeria

Evaluation of the specific activity of radioactivity in tubers is an important tool in the assessment of human internal exposure to radiation through ingestion. In this research, the activity concentrations of natural radionuclides 40 K, 238 U and 232 Th in sweet potato samples taken from different farm lands in the six geopolitical zones of Nigeria were determined by means of gamma spectrometry. Using standard calibrated NaI (TI) and shielded detector coupled to a computer resident quantum MCA2100R Multichannel analyzer for 36,000 s. The activities were estimated to be 526.39 ± 51.40, 8.55 ± 1.76 and 1.14 ± 0.42Bq/kg respectively for 40 K, 238 U and 232 Th. The estimated daily intake through potato diet are 6.6622, 4.6860, 4.6748, 2.75103, 2.7453, and 2.3983 Bq.d
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for South-East (Abia), South-South(Edo), South-West(Oyo), North-Central (Kwara), North-West (Sokoto), and North-East (Adamawa) respectively. Findings showed that potato plants uptake and transport radionuclides from the soil by the root system. It also showed that 40 K is the most radionuclides contaminant presents in the farm soil where the potato plants were grown. The daily intake of radionuclides was also observed to be highest in 40 K. This may be due to the use of phosphate rich fertilizer in the farmlands where they were grown. The overview of the research showed that the annual effective doses due to potato diet, at this present rate, pose no significant threat to the public.