Committed effective dose determination in southern Brazilian cereal flours

The health impact of radionuclide ingestion from foodstuffs was evaluated by the committed effective doses determined in eight commercial samples of South-Brazilian cereal flours (soy, wheat, cornmeal, cassava, rye, oat, barley and rice flours). The radioactivity traces of Th, Ra, Ra, K, Be and Cs were measured by gamma-ray spectrometry employing an HPGe detector of 66 % relative efficiency. The efficiency curve has taken into account the differences in densities and chemical composition between the matrix and the certified sample. The highest concentration levels of Th and K were 3.5+0.4 and 1469+17 Bq kg for soy flour, respectively, within the 95 % confidence level. The lower limit of detection for Cs ranged from 0.04 to 0.4 Bq kg. The highest committed effective dose was 0.36 mSv.y for Ra in cassava flour (adults). All committed effective doses determined at the present work were lower than the International Atomic Energy Agency dose limit of 1 mSv.y, to the public exposure.