226Ra and 228Ra activities in French foodstuffs

The activities of 228 Ac and 214 Bi in French foodstuffs acquired during the last 15 years allow one to obtain reference values of 228 Ra and 226 Ra activities which are usable to assess the dose to the French population due to the intake of these two natural radionuclides. As expected, because of similar 238 U and 232 Th activities in French soils (around 40 Bq.kg -1 ), the 226 Ra/ 228 Ra activity ratio in French terrestrial foodstuffs is close to 1. Most kinds of foodstuffs present similar mean activities: from 0.1 to 0.2 Bq.kg -1 fresh for cereals, leafy vegetables, root vegetables, eggs and fishes (marine and freshwater). The activity in fruits is lower, around 0.05 Bq.kg -1 , similar to that of meat calculated on the basis of the numerous grass measurement results. The lowest activities are noticeable for milk: around 0.015 Bq.L -1 . All these values are in good agreement with the data from various countries, but most often 2 to 3 times higher than the reference values proposed by UNSCEAR. This study also shows that due to the large variability of foodstuff activities reported by a large amount of data, it is not possible to distinguish the activities of samples from regions with a gap of only a factor of 2 between their soil activities.