ASSESSMENT OF RADIONUCLIDES IN SOME NIGERIAN MADE CEREALS AND TEA PRODUCTS

Abstract

This study investigated the presence of the radionuclides 226Ra, 232Th, 40K and 137Cs in some cereals and tea products commonly available in Nigerian markets. Fifteen cereal samples and ten tea samples were purchased from different markets in Lagos, Nigeria. Gamma-ray spectrometric analyses of the samples were done using a High Purity Germanium (HPGe) detector to obtain the activity concentrations of the radionuclides with 137Cs being below the detection limit in all the samples analyzed. The mean activity concentrations (in Bqkg-1) of 226Ra, 232Th and 40K in the cereal samples were (0.839 ± 0.713), (1.153 ± 1.084) and (22.514 ± 8.897) respectively; while the values for the tea samples were (1.145 ± 0.765), (0.94 ± 0.601) and (19.212 ± 9.533) respectively. The associated hazard indices for the cereals ranged from 0.0065 to 0.0368 while that for the tea products varied from 0.0044 to 0.0292. These values are well below the world recommended limit of 1.0. The calculated annual effective doses due to the ingestion of the investigated samples ranged from 0.068 mSvy-1 (for age groups from 1 y) to 0.189 mSvy-1 (for age group 17 y). For the tea samples, the highest value was found in the age group 12 – 17 y, while the lowest was found in the age group 1 – 2 y. These values are below the allowable level of 1 mSv per annum for members of the general public as recommended by the International Commission on Radiological Protection. This indicates that the consumption of these cereals and teas do not pose as health hazards to both children and adults in the populace.