Gastrointestinal tract uranium ingestion

Uranium ingested from food and water ingestion ranges from 1-5 pg uranium in uncontaminated regions to 13-18 pg uranium in uranium mining areas (ATSDR, 1999). The absorption of uranium across the gastrointestinal tract is related to the solubility of the compound and generally increases with increased solubility. Only a small fraction is... 

Ingested uranium is excreted mostly in the feces urinary excretion is generally low. The biological halftimes of soluble uranium compounds (uranium hexafluoride, uranyl fluoride, uranium tetrachloride, uranyl nitrate hexahydrate) are estimated in days or weeks those of the less soluble compounds (uranium tetrafluoride, uranium dioxide, triuranium octaoxide) are estimated in years. No information is currently available on the excretion of dermally absorbed uranium. Transdermally absorbed uranium is expected to behave identically to uranium compounds absorbed through the lungs and the gastrointestinal tract. 

The value for the fractional absorption of ingested uranium (fj) was adjusted from the adult value of 0.02 (2%) to a value of 0.04 (4%) for children under the age of 1 year. This adjustment was made based on animal data (Sullivan et al. 1980b Sullivan and Gorham 1982) and information on postnatal changes in the human gastrointestinal tract. For ages over 1 year, the adult value for fractional absorption was used. 

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