RESUMO
Internal exposure of public to radiation arising from ingestion of natural radionuclides in tuber crops of Ebonyi State origin was investigated in this study. Committed effective doses and lifetime cancer risk of 40K, 226Ra, and 232Th in cassava, cocoyam, water yam, and white yam were calculated. The average activity concentrations of 40K, 226Ra, and 232Th determined by gamma spectrometric Na (TI) detector were, respectively, 199.15 ± 23.51, 77.57 ± 7.98, and 118.20 ± 10.72 Bq/kg in cassava; 146.62 ± 40.69, 43.42 ± 7.63, and 75.61 ± 2.89 Bq/kg in cocoyam; 162.81 ± 20.43, 63.17 ± 11.36, and 81.50 ± 10.27 Bq/kg in water yam; and 184.50 ± 20.22, 80.23 ± 10.93, and 116.29 ± 5.93 Bq/kg in white yam. The total committed effective dose via ingestion aligned in this order of cassava (7.05 mSv/year) > white yam (4.38 mSv/year) > water yam (0.42 mSv/year) > cocoyam (0.21 mSv/year) with overall average dose of 3.12 mSv/year. The values of dose were higher than world average of 0.29 mSv/year given by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The lifetime cancer risk values were above tolerance level of >10-4 prescribed by United States Environmental Protection Agency (USEPA), suggesting probable evolvement of radiogenic cancer morbidity. The data presented in this study contributes to baseline information on radiological characteristics of tuber crops in Ebonyi, which would be valuable to WHO/FAO food safety policy in Nigeria and rest of the world.
