Dose efetiva comprometida devida aos radionuclídeos 40K, 226Ra, 228Ra e 228Th contidos nos alimentos da dieta da população do Estado do Rio de Janeiro

Abstract

Committed effective dose due to the consumption of natural radionuclides 40K, 226Ra, 228Ra and 228Th was estimated from the high-resolution gamma spectrometry, food consumption data for the inhabitants of Rio de Janeiro state and dose coefficients published by the ICRP 119. The analyzed samples were cereals, grains, vegetables, flours, liquids and perishables. Energy calibration was done using certified point sources and the detection efficiency for each sample was obtained from LabSOCS software. In all samples, 40K was the only element that presented specific concentration value above the MDA. However, the greatest contribution to the committed effective dose was due to 226Ra and 228Ra, with 986 μSv.y-1 and 208 μSv.y-1, respectively. The major contributors to the dose were liquids and cereals, with 875 μSv.y-1 and 564 μSv.y-1, respectively. The total committed effective dose was 1.36 mSv.y-1, almost 5- fold higher than the value suggested by UNSCEAR. The main contributor to this value was the specific concentration of 226Ra and 228Ra in bean and water measured in this work, since these two radionuclides have the largest effective dose conversion factors among the radionuclides studied here, and the two foods present the highest annual consumption averages among all the foods studied