Contents and Daily Intakes of Gamma-Ray Emitting Nuclides, 90 Sr, and 238 U using Market-Basket Studies

To investigate the contents of radionuclides in foods marketed in Japan and their daily intakes and exposure doses in adults, we performed market-basket studies concerning radionuclide intakes. The study period was 2003– 2005, and the studies were performed in 13 cities in Japan .F oods including drinking water were divided into 14 food groups, and samples were prepared by common cooking procedures. γ-ra ye mitting nuclides (an artificial radionuclide, radioactive Cs, and natural radionuclides, 40 Ka nd Us eries such as 214 Bi, and 212 Pb, and Th series) were measured in each food group, and artificial radionuclides, 90 Sr and 238 U, were measured in a mixed sample of 13 food groups excluding drinking water. The daily intakes in adults were calculated from the concentrations of th er adionuclides and mean daily consumption of foods and drinking water. The daily 137 Cs and 40 Ki ntakes (mBq/ person · day) in the 13 cities were 12.5–<79.7 and 57309–95746, respectively. The 90 Sr intake from the food groups excluding drinking water was 20.8–53.6, with a mean of 39.2 (mBq/person · day) (deviation of the mean: 23%). Similarly, the daily 238 Ui ntake was 5.9–31.1, with a mean of 12.6 (mBq/person · day) (deviation: 60%), showing am ore than 5-fold difference between the minimum and maximum values, and there were regional differences. Since the contents of the U series, such as 214 Bi and 212 Pb, and Th series were lower than the lower detection limits in many samples, their daily intakes were not calculated. Regarding the daily intake of 137 Cs from each food group, the intakes from fish and shellfish, milk, meat/eggs, and mushrooms/seaweed tended to be higher. The daily 40 K intake from each food group varied among the areas, but th et otal intake from the 14 food groups was similar in all 13 cities. 40 K from these foods accounted for most of the annual effective dose (µSv/person · year) of γ-ra ye mitting nuclides, and the doses of 40 K, 90 Sr, and 238 Uw ere 130–217, 0.21–0.55, and 0.10–0.51, respectively.