Annual Committed Effective Doses of Primordial Radionuclides and Excess Lifetime Cancer Risk to the Consumers of

Abstract

Food plays vital role in the survival of man as it provides necessary nutrients to the body in order to carry out the daily activities and also to be in good health. Activity concentrations of 40K, 238Uand 232Th in some foodstuffs from three highly rated markets in Lagos, Southwest of Nigeria have been determined by gamma spectrometry method using NaI (TI) detector coupled with a pre-amplifier base to a multiple channel analyzer (MCA). Fifteen (15) samples of maize flour, yam flour, beans, cassava flour and rice were randomly purchased from the markets: Ketu, Oyingbo and Ikeja. The highest activity concentrations for 40K, 238U and 232Th were 153.47 ± 10.34 Bq kg ˆ’1, 9.26 ± 2.17 Bq kg ˆ’1 and 15.36 ± 4.05 Bq kg ˆ’1, respectively, all from yam flour. The mean concentrations of 40K for all the samples were obtained to be 102.33 ± 7.04 Bq kg ˆ’1, 5.79 ± 1.35 Bq kgË—1 for 238U and 9.15 ± 2.36 Bq kg ˆ’1 for 232Th. The average annual committed effective dose of all the natural radionuclides to the consumers of the foodstuffs was determined to be 0.144 mSv yr ˆ’1 and average excess lifetime cancer risk to the consumers was determined to be 0.503 x 104. The values obtained were below the worldwide limits of 1 mSv yr ˆ’1 and 0.29 x 10 ˆ’3, respectively, which indicated that consumption of the foodstuffs had no significant negative radiological health risks to the consumers.

Keywords: Radionuclide; Activity concentration; Foodstuff; Dose; Gamma spectrometry;