Uranium behaviour in the baboon after the deposition of a ceramic form of uranium dioxide and uranium octoxide in the lungs: Implications for human exposure

UO₂ and U₃O₈ were inhaled by baboons in amounts such that the mass concentrations in the lungs were between about 3 and 20, and 1 and 7.4 times respectively those calculated in human lungs after exposure to 1 ALI of the compounds. The results show that 1 year later: 1) the initial lung deposits ofuranium retained in the chest are greater for UO₂ than for U₃O₈; 2) the ratios of the amounts of uranium retained in the lymph nodes vs those in the lungs, expressed both in terms of concentration and mass, are greater for UO₂ than for U₃O₈; 3) for both UO₂ and U₃O₈, the amounts of uranium retained in the lymph nodes, expressed as a percentage of that in the chest, do not appear to be affected to a great extent by the initial lung deposits; 4) after inhalation of UO₂ and U₃O₈ in different amounts, the trend in the mass concentrations of uranium in the various tissues assayed were lymph nodes › lungs ›› skull › femoraclavicles › lumbar vertebra – thoracic cage › sternum › kidneys › liver; 5) the measurement of urine concentrations of some enzymes may be a useful indexfor assessing substantial overexposures to UO₂ and U₃O₈, however, so far, external chest monitoring and urinary assays of uranium should remain the procedures of choice.