ASSESSMENT OF RADIOACTIVITY AND CONCOMITANT DOSE IN VEGETABLES GROWN IN KUDAN, KADUNA STATE, NIGERIA

Abstract

The natural radioactivity level in soil can be elevated by human activities especially technological advancement and nuclear technology proliferation. Therefore, it is important to assess the concentration of radioactive materials in vegetables due to the transfer of radionuclides in the chain soil-plant-human via ingestion. Using NaI detector, the present study was undertaken to measure the concentration of 226Ra, 228Ra and 40K in more prominent vegetables (Tomatoes, cabbage and lettuce) grown in Kaduna, Nigeria. For 226Ra, 228Ra and 40K, the mean activity concentrations (Bq/kg) were 73.5, 33.2 and 90.4 respectively in tomatoes, 78, 23.6 and 129.2 in cabbage and 82.4, 30.8 and 188.6 in lettuce. Overall, the measured data were found to be below the average value of 82Bq/kg and 310Bq/kg for 228Ra and 40K respectively, while for 226Ra the values were above the average value of 67Bq/kg prescribed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The annual effective dose, radium equivalent and internal hazard index were all below the permissible limit of 1mSv/y, 370Bq/kg and 1 respectively as recommended by UNSCEAR. The lifetime cancer risk from consumption of the studied food was also assessed and found to be below the International Commission On Radiological Protection (2012) cancer risk factor of 4.5×10-3 based on additional annual dose limit of 1mSv for the general public. Therefore, consumption of the vegetables does not pose any substantial threat to the public.