Committed effective dose from naturally occuring radionuclides in shellfish

Recognizing their importance in the average Malaysian daily diet, the radioactivity concentrations in mollusc- and crustacean-based food have been determined for key naturally occuring radionuclides. Fresh samples collected from various maritime locations around peninsular Malaysia have been processed using standard procedures; the radionuclide concentrations being determined using an HPGe gamma-ray spectrometer. For molluscs, assuming secular equilibrium, the range of activities of U-238 (Ra-226), Th-232 ((228)Ka) and K-40 were found to be 3.28 +/- 0.35 to 5.34 +/- 0.52, 1.20 +/- 0.21 to 2.44 +/- 0.21 and 118 +/- 6 to 281 +/- 14 Bq kg(-1) dry weight, respectively. The respective values for crustaceans were 3.02 +/- 0.57 to 4.70 +/- 0.52, 1.38 +/- 0.21 to 2.40 +/- 0.35 and 216 +/- 11 to 316 +/- 15 Bq kg(-1). The estimated average daily intake of radioactivity from consumption of molluscs are 0.37 Bq kg(-1) for U-238 (Ra-226), 0.16 Bq kg(-1) for Th-232 (Ra-228) and 18 Bq kg(-1) for K-40; the respective daily intake values from crustaceans are 0.36 Bq kg(-1), 0.16 Bq kg(-1) and 23 Bq kg(-1). Associated annual committed effective doses from molluscs are estimated to be in the range 21.3 to 34.7 mu Sv for Ra-226, 19.3 to 39.1 mu Sv for Ra-228 and 17.0 to 40.4 mu Sv for K-40. For crustaceans, the respective dose ranges are 19.6 to 30.5 mu Sv, 22.0 to 38.4 mu Sv and 31.1 to 45.5 mu Sv, being some several times world average values. (c) 2013 Elsevier Ltd. All rights reserved.