Unethical human experimentation in the United States
In 1953, the AEC ran several studies at the University of Iowa on the health effects of radioactive iodine in newborns and pregnant women. In one study, researchers gave pregnant women from of iodine-131, in order to study the women's aborted embryos in an attempt to discover at what stage, and to what extent, radioactive iodine crosses the placental barrier. In another study, they gave 25 newborn babies (who were under 36 hours old and weighed from ) iodine-131, either by oral administration or through an injection, so that they could measure the amount of iodine in their thyroid glands, as iodine would go to that gland.
Iodine-125
To isolate radioiodine, the irradiated capsule is first cooled (to collect free iodine gas on the capsule sides) and the remaining Xe gas is allowed to escape. The inner walls of the capsule are then rinsed with dilute NaOH solution to collect iodine as soluble iodide and hypoiodite OI, according to the standard disproportionation reaction of halogens in alkaline solutions. Any cesium immediately oxidizes and passes into the water as Cs. In order to eliminate any long-lived Cs and Cs which may be present in small amounts, the solution is passed through a cation-exchange column, which exchanges Cs for another non-radioactive cation. The radioiodine (as anion I or OI ) remains in solution as iodide/hypoiodite.