Radionuclide contents in food products from domestic and imported sources in Nigeria.

Samples of some domestic and imported food products of nutritive importance to both the child population and the adult population in Nigeria were collected and analysed in order to determine their radionuclide contents. The samples were collected from open markets in major commercial cities in the country. Gamma-ray spectrometry was employed in the determination of the radionuclide contents in the products. The gamma-ray peaks observed with reliable regularity in all the samples analysed belong to naturally occurring radionuclides, namely (226)Ra, (228)Th and (40)K. The activity concentrations of these radionuclides in both the domestic and imported products were observed to be not significantly different. Essentially radioactive elements such as (137)Cs were not detected in any of the samples. The non-detection of (137)Cs in the imported products may be attributed to the suitably modified agricultural practices and countermeasures being employed to reduce caesium uptake by plants after the Chernobyl nuclear reactor accident. It seems unlikely that the elemental concentrations in the food products analysed will contribute significantly to public health risks in the country, as the cumulative ingestion effective dose values from (226)Ra and (228)Th were found to be low. Although (40)K has the highest activity concentrations in all the samples analysed, it is usually under homeostatic control in the body, and hence the concentrations are irrelevant to possible contamination in the food products analysed.