Human metabolism of radiocaesium revisited

Three adult volunteers (2 males and I female) have ingested radioactive caesium in two edible forms in order to compare the gastrointestinal uptake and the subsequent short-term and long-term biokinetics. Foodstuffs made of fresh-water fish or mushrooms from regions in Sweden of high Cs-137 deposition was ingested together with a (CsCl)-Cs-134-solution mixed with soft drinks. Whole-body countings of Cs-134 and Cs-137 were performed in the Malmo whole-body counter during a period of similar to50 d prior to, and 200-300 d after the ingestion. Urine and faeces were collected the day before and up to 7-10 d after the test meals, and analysed for Cs-134 and Cs-137. No significant difference in the gastrointestinal uptake fraction, f(0) = 0.98 between caesium incorporated into a foodstuff matrix and caesium in ionic form was detected. Cumulated faecal excretion during 7 d after ingestion accounted for 2-3% of the intake. No significant difference in the long-term biological half-time was found between caesium present in a food matrix and in an aqueous solution in any of the volunteers.