REMOVAL OF INHALED PLUTONIUM AND AMERICIUM FROM THE RAT BY ADMINISTRATION OF ZNDTPA IN DRINKING-WATER

This study has examined the efficacy of ZnDTPA administered in drinkin g water for removing Pu-238 and Am-241 from the rat after their simult aneous inhalation as nitrates; the dosage used was 95 mumol kg-1 d-1. The continuous administration of ZnDTPA over a 14 d interval, commenci ng 1 h after exposure, reduced the lung and total body contents of Pu- 238 to, respectively, 11% and 18% of those in untreated rats; the corr esponding values for Am-241 were 11% and 14%. After the continuous adm inistration of 95 mumol kg-1 from 4 d to 28 d post exposure, the lung and total body contents of Pu-238 were, respectively, 5% and 16% of th ose in controls; the corresponding values for Am-241 were 7% and 19%. Further reductions in the actinide contents of body tissues were found when treatment was extended to 52 d or 76 d. These regimens were as e ffective as twice weekly injections of 30 mumol kg-1 ZnDTPA commencing at 4 d. After the continuous administration of 95 mumol kg-1d-1 for 7 2 d, some pathological changes to the gastrointestinal tract were obse rved but these were considered to be reparable. It was concluded that further work is required to evaluate the toxicity of the ligand and to establish the optimal treatment regimen.