REDUCTION OF CESIUM CONCENTRATION IN OVINE TISSUES FOLLOWING TREATMENT WITH PRUSSIAN-BLUE LABELED WITH FE-59

The effectiveness of Prussian Blue in reducing the radiocesium contami nation in ovine tissues was investigated, Five ewes were fed Cs-137-co ntaminated wheat for 30 d, When the Cs-137 concentration in milk had r eached equilibrium, one animal, serving as the control, was slaughtere d and the activity in its tissues was measured, Two ewes were offered daily 1 g of Prussian Blue labeled with Fe-59 in the Fe(III) position, outside the complex anion, One week after the administration of Pruss ian Blue, these animals were slaughtered, 1 wk apart, and the level of Cs-137 in their tissues was measured, Comparing the concentration of Cs-137 in the blood and tissues of the Prussian Blue treated animals t o the corresponding concentrations measured in the control, a consider able reduction in the radiocesium activity concentration is observed, However, Cs-137 concentrations are maintained at non-zero (about 20%) values in the first 2 wk after the administration of Prussian Blue, Th is observation can be attributed to the fact that most of Cs-137 binds to Prussian Blue in the animals' digestive tracts and the measured ac tivity concentrations follow the elimination of cesium from tissues, U sing a two-compartment mathematical model, we can predict the level of Cs-137 in tissue, following the administration of Prussian Blue, Labe ling Prussian Blue in the Fe(III)-position resulted in the measurement of a (2.4 +/- 0.02) % retention of Fe(III) in sheep.