Retention of plutonium in the beagle after gastrointestinal absorption

A 0.01 M bicarbonate solution containing 130 nCi (approximately 5 kBq) of 237Pu (90% hexavalent, 93% ultrafilterable) was administered via gelatin capsule to six adult male beagles following a 21-hr fast. The dogs were sacrificed after 5-6 weeks and the percentage of the administered plutonium retained in the liver plus skeleton and its distribution within the skeleton were determined. The mean amount retained in these tissues was (0.063 +/- 0.006)% of the administered dose. The mean amounts of plutonium in the liver and the skeleton were approximately equal, and the distribution within the skeleton was similar to that observed by other workers following either intravenous injection or inhalation. Our value for plutonium retention by the dog is about a factor of three less than the values we have reported for rodents. It is a factor of 7 greater than the product of the values for gastrointestinal absorption (f1) and fractional retention (f2) recommended by the ICRP for man.