Evaluation of plutonium at Enewetak Atoll

An extensive survey was carried out in 1972 to 1973 to assess the current radiological status of Eniwetok Atoll. The radionuclides detected in the Atoll environment were studied for their potential contributions to the dose commitment of the returning population according to several pathways of exposure. Plutonium was detected in air and in the terrestrial and aquatic environment at concentrations that varied from background levels due to world-wide fallout to levels several orders-of-magnitude above. The dose commitments from plutonium via the terrestrial food chain and inhalation vary according to the postulated living pattern. The dosages via marine foods can be expected to be insensitive to living pattern and to exceed those via terrestrial foods. Plutonium would contribute nearly all of the dosage via inhalation, but this pathway ranks low in overall importance compared with the food-chain and external-dose pathways. Although the potential dose from plutonium via all pathways is low relative to that from $sup 60$Co, $sup 90$Sr and $sup 137$Cs, plutonium will still remain in the Atoll environment after the other major isotopes have decayed away. (auth)