Natural Radioactivity in Some Selected Powdered Milk Brands Consumed in Nigeria and Corresponding Annual Effective Dose
Umar Ahmed, Matthew Tikpangi Kolo , Oyeleke Ismail Olarinoye
Keywords: Effective dose, Ingestion, Natural radioactivity, Powdered milk.
Abstract
Regulation and monitoring of radionuclides in foodstuff is important for human health maintenance. Powdered milk is rich in minerals and protein contents which are essential for healthy growth and development. Five (5) brands of powdered milk commonly consumed in Nigeria were collected and analysed for their natural radioactivity content. The analysis was carried out using gamma ray spectrometry system consisting of a 3×3 inch NaI(TI) detector. Results showed that the activity concentration of 40K varied from 13.19 ± 1.18 to 136.78 ± 13.81 Bq kg-1 with average of 64.25 ± 7.25 Bq kg-1 . Activity concentration of 238U varied from 0.58 ± 0.11 to 5.23 ± 1.90 Bq kg-1 , with mean value of 2.39 ± 0.60 Bq kg-1 , while the activity of 232Th varied from 0.40 ± 0.05 to 3.61 ± 0.47 Bq kg-1 with average value of 1.93 ± 0.28 Bq kg-1 . Computed mean Raeq was found to be 10.10 ± 1.57 Bq kg-1 . The Raeq evaluated was below the UNSCEAR limit of 370 Bq kg-1 . Total mean annual effective dose due to intake of 238U, 232Th and 40K from ingestion of powdered milk by the infants (ages 0 to 2 years), children (ages 2 to 17 years) and adults (>17 years) are lower than the safety limit of 1.0 mSvy-1 for all ages recommended by the International Commission on Radiological Protection. Hence the consumption of milk products does not pose any significant health challenge to the population.