Estimation of daily uranium ingestion by urban residents in Japan

125 types of food were collected mainly from Yokohama City which is one of the typical urban cities in Japan. The samples, were divided into the 18 food categories in the report of the National Nutrition Survey (NNS),¹ were analysed for uranium by -spectrometry after chemical separation. Concentrations of²³⁸U in individual types of food ranged from 9.85·10^–5 Bq·kg^–1 in grain vinegar to 5.90 Bq·kg^–1 in boiled and dried hijiki. The median value of²³⁸U was found to be 4.83·10^–3 Bq·kg^–1 on a raw weight basis. The daily intake of²³⁸U per person by ingestion was estimated to be approximately 14 mBq with more than 50% of it coming from marine products.