17 May 1973 SUGGESTIONS FOR INCLUSION IN THE ENVIRONMENTAL IMPACT STATEMENT FOR THE ENIWETC ATOLL CLEANUP 3g Present Condition of Islands - Results of Radiological Survey R. B. Leachman Defense Nuclear Agency Introduction . - 8 . n The radioactivity on Eniwetok Atoll results almost entirely from the nuclear explosions at the Atoll from 1948 until 1958. Some radio- activity results from fallout from nuclear explosion tests conducted elsewhere in the atmosphere, but this is probably insignificant compared to radioactivity produced by tests on Eniwetok Atoll. The minimum radio- activity observed on any island on Eniwetok Atoll in 1973 was more than an order of magnitude greater than that of world-wide fallout and of local natural radioactivity trom cosmic rays aid minerals. (Beir, 1972) Although the southern islands were the scene of only two underwater tests off Henry, an island downwind from most other southern islands, this low residual activity on the southern islands of Eniwetok Atoll are thus seen to result almost entirely from local fallout from tests conducted at Eniwetok Atoll. Only after many decades, and in some places only after centuries, will the local radioactive debris from these tests undergo natural nuclear decay to the extent that the remaining radioactivity is as low as the radioactivity from natural causes, principally cosmic rays at this location. For the case of the plutonium-239 residual, actually many, many millennia wouldcorrespondingly be required. Of course,