Abstract:
The activity concentrations of 40K, 232Th and 226Ra in twenty eight food samples (10 fruits, 10 vegetables and 8 tubers) commonly consumed in Nigeria has been measured using a high purity germanium, (HPGe) detector system. The mean specific activities of 40K, 232Th and 226Ra varied from 0.16 to 21.70; 0.23 to 1.77; 0.94 to 22.4 Bq kg-1 respectively in fruits, while in vegetables the mean specific activities of these radio-nuclides varied from 0.23 to 4.19; 0.25 to 1.43; 7.71 to 39.84 Bq kg-1 respectively. In tubers the mean specific activity concentrations varied from 0.29 to 4.62; 0.24 to 2.95; 6.20 to 23.54 Bq kg-1 for 40K, 232Th and 226Ra respectively. The total annual effective dose for fruits within the age groups considered were 0.0136 – 1.0010, 0.0087 – 0.6472, 0.0110 – 0.8327, 0.0203 – 1.5569 and 0.0039 – 0.2933 mSv y-1 for age group 1-2y, 2-7y, 7-12y, 12-17y and >17y respectively for fruits while in vegetables, the total annual effective dose range between 0.3636 -2.2528, 0.2360 -1.4572, 0.2709 – 1.8667, 0.5575 – 3.4776 and 0.1081 – 0.6618 mSv y-1 for age group 1-2y, 2-7y, 7-12y, 12-17y and >17y respectively. For tubers, it ranged between 0.0451 – 1.8333, 0.0292 – 1.1909, 0.0374 – 1.5110, 0.0696 – 2.7887 and 0.0133 – 0.5470 mSv y-1 for age group 1-2y, 2-7y, 7-12y, 12-17y and >17y respectively. Generally, the results which is far less than the ICRP standard did not show any significant health impact, except for age group 12-17 y that are most susceptive to radioactivities in the food samples considered. The result of the study will serve as a useful radiometric data for future epidemiological studies and for food safety regulations and policy implementations in the country. It is recommended that seasonal variations in radionuclide transfer should be investigated and regular monitoring should be conducted from time to time to check any eventuality as a result of long time consumption of the foodstuffs.
