The effect of two forms of Prussian blue, soluble K3 Fe[Fe(CN)6] and insoluble Fe4[Fe(CN)6]3, and of ammonium iron hexacyanoferrate (II) (NH4Fe[Fe(CN)6] on intestinal radiocesium absorption was investigated in rats, pigs, and humans. In rats 5 mg of antidote administered 2 min before 134Cs tracer reduced radiocesium absorption to 2.4-6.3% of the oral dose. In pigs fed with Chernobyl-contaminated whey under normal feeding conditions for a 27 day period, radiocesium activity concentration was reduced from 360 Bq/kg in control animals to 10-30 Bq/kg by 5 g antidote/d. In man 1 g of oral Prussian blue diminished the cesium absorption from a 134Cs-labelled test meal to 5.6-6.4% of the controls. The inhibitory effects of colloidally soluble K3 Fe[Fe(CN)6] and of (NH4Fe[Fe(CN)6] were similar with slightly less inhibition by the insoluble Fe4[Fe(CN)6]3.
