Daily ingestion of Th-232, U-238, Ra-226, Ra-228 and Pb-210 in vegetables by inhabitants of Rio de Janeiro City

The concentrations of the naturally occurring radionuclides Th-232, U-238, Pb-210, Ra-226 and Ra-228 were determined in the vegetables (leafy vegetables, fruit, root, bean and rice) and derived products (sugar, coffee. manioc flour, wheat flour, corn flour and pasta) consumed most by the adult inhabitants of Rio de Janeiro City, A total of 88 samples from 26 different vegetables and derived products were analyzed. The highest contribution to radionuclide intake arises from bean, wheat flour, manioc flour. carrot, rice, tomato and potato consumption. The estimated daily intakes due to the consumption of vegetables and derived products are 1.9 mBq of Th-232 (0.47 mug), 2.0 mBq of U-238 (0.17 mug), 19 mBq of Ra-226. 26 mBq of Pb-210 and 47 mBq of Ra-228. The estimated annual effective dose due to the ingestion of vegetables and their derived products with the long-lived natural radionuclides is 14.5 muSv. Taking into account literature data for water and milk from Rio de Janeiro the dose value increases to 29 muSv, with vegetables and derived products responsible for 50% of the dose and water for 48%. Pb-210 (62%) and Ra-228 (24%) were found to be the main sources for internal irradiation. (C) 2002 Elsevier Science Ltd. All rights reserved.