Relationship between turnover of cesium-137 and dietary potassium content in potassium-restricted mice

The biological half-life of 137Cs and its organ distribution were investigated in mice fed various potassium-deficient diets. The biological half-life, which was 6.1 days in mice receiving the normal level of potassium, became longer as the dietary potassium content decreased, and 137Cs was hardly excreted from the body when dietary potassium content was restricted to 200 mg/kg or less. The muscle showed the highest concentration of 137Cs in both mice that had sufficient amounts of potassium and those that were potassium-deficient. Clearance of 137Cs from tissues was generally suppressed when mice were fed a potassium-deficient diet, but the relative distribution pattern of 137Cs was not affected by dietary potassium content. These results suggest that dietary potassium intake, which may vary with eating habits, affects the biological half-life of 137Cs in humans.