Studies With Neptunium in the Rat

Abstract

Studies are reported on the inhalation, pulmonary absorption, gastrointestinal absorption, and short-term retention of Np237 in rats. From 1 to 5 per cent of neptunium deposited in the lung was retained for periods of time up to 3 weeks. As much as 2 per cent of that deposited was translocated to bone. Depending on the chemical and physical state of the material fed, 0.1–2.3 per cent was absorbed from the intestinal tract. The hexavalent form was most readily absorbed. Intravenously injected neptunium was initially deposited in highest concentration in the liver, but was lost quite rapidly from this organ and, after 3 days, was present in highest concentration in bone.