Tritium and plutonium content in the Italian diet and transfer to man

Complete daily diets together with total daily excretion and blood samples have been collected for five days in a group of healthy subjects of both sexes, representative of the normal Italian population living in an environment unexposed to local releases of plutonium and tritium. The tritiated water content available by freeze drying ('loose water fraction') has been measured together with the additional tritium available by complete combustion ('organic bound fraction') in the various samples collected. The mean values of the daily dietary intake of tritium were 974 pCi for the organic bound fraction and 310 pCi for the loose water fraction. The metabolic balance in man was evaluated for both fractions by comparing the daily intake with the daily excretion and blood concentration data. The results indicate that to assess tritium exposure of the general population one must take into account the environmental sources and the metabolic behaviour in man of tritium in both the bound and loose compartments. The plutonium content has been measured in the diet samples only because of the very low concentration in excreta and blood. The yearly dietary intake of plutonium in Italy is of the order of 1.5 pCi, in good agreement with the data available in other countries. (author)