Most ingested uranium is excreted during digestion. Only 0.5% is absorbed when insoluble forms of uranium, such as its oxide, are ingested, whereas absorption of the more soluble uranyl ion can be up to 5%. However, soluble uranium compounds tend to quickly pass through the body, whereas insoluble uranium compounds, especially when inhaled by way of dust into the lungs, pose a more serious exposure hazard. After entering the bloodstream, the absorbed uranium tends to bioaccumulate and stay for many years in bone tissue because of uranium's affinity for phosphates. Uranium is not absorbed through the skin, and alpha particles released by uranium cannot penetrate the skin. COUNT 5
QSN1 What happens to a majority of ingested uranium? ANS1 excreted QSN2 Up to what percentage of uranyl ion can be absorbed when ingested? ANS2 5% QSN3 About what percentage of uranium oxide is absorbed when ingested? ANS3 0.5% QSN4 What does uranium have an affinity for? ANS4 phosphates QSN5 Where does uranium accumulate in the body? ANS5 bone tissue