The metabolism of caesium-137 in dairy cows

Abstract

1. The metabolism of 137Cs in dairy cows has been studied after single oral and intravenous doses and during twice daily oral dosing for 28 days.2. Gastrointestinal absorption of 137Cs was about 70-80% of the oral doses.3. After 28 days continuous feeding the mean concentration of 137Cs in milk was 0.84% daily dose/1. and the body burden of the isotope varied between 5.7 and 8.2 times the daily intake.4. When feeding of 137Cs stopped the concentration of the isotope in milk fell by a factor of five in 8 days, by a factor of ten in 16 days, by a factor of twenty in 32 days, and thereafter exponentially with a half-life of 30 days. The concentrations of the isotope in muscle decreased at first rather slowly but finally also exponentially with a half-life of approximately 30 days.