—y 272 RADIOLOGICAL CLEANUP OF ENEWETAK ATOLL 238 in their comments on the EIS37 by noting that the uptake of Am-24| in the food chain, which would double due to radiodecay of Pu-241, maybe the critical pathway. There appeared to be higher tumor risks for Pu-238 than for Pu-239.38 DNA pointed out that the AEC Task Group Report cleanup criteria clearly stated that cleanup of Pu-239/240 negated any contribution by Pu-238 or Pu-24! and that the report did not even mention other transuranics. The impact of this issue became more apparent when, following some radiation counting experiments with Enewetak soil by Field Command, it became evident that Pu-238 concentrations were significant. This caused concern since cleanup estimates had been based on volumes of soil containing Pu-239/240 only, and the AEC guidelines on cleanup were not clear with respect to inclusion of other plutonium isotopes. Dr. Wachholz also advised DNA that if transuranic contamination were cleaned to below 40 pCi/g on residential islands, the Enewetak cleanup probably would meet the new EPA guidelines; but if transuranic contamination of over 40 pCi/g were left on residential islands, the cleanup probably would not meet the new guidelines. Linking the previous two items, ERDA informed DNA that the AEC/ ERDA guidelines for residential islands had always been intended to include total transuranics, even though they named only plutonium.39 DNA pointed out that, in fact, AEC/ERDA’s numerical guideline of 40 i i pCi/g for soil cleanup actions had not been related to residential use, or any other particular use, in either the AEC Task Group Report or the criteria ERDA recommended for the OPLAN. DNA also pointed out that there was no requirement in the AEC Task Group Report, the EIS, or the OPLAN for plutonium cleanup of any residential island. This reopened the issue of using Enjebi for residence. ERDA then advised DNA that the ERDA staff had always intended to place top cleanup priority on reducing levels of contamination on Enjebi to less than 40 pCi/g. This came as a surprise to DNA, because the AEC Task Group specifically recommended no soil removal for Enjebi, but simply the conduct of tests to determine when exposures would be within acceptable criteria.4° The AEC Task Group’s guidance for case-by-case decisions on soil levels between 40 and 400 pCi/g indicated that soil removal was better justified on larger islands such as Aomon or Enjebi, where residences might someday be located, but its Report gave no numerical criteria for residential use.4! Nevertheless, ERDA nowstated that unless Enjebi was cleaned to less than 40 pCi/g of transuranics, the concept that Enjebi could be used as a residence after some 30 years could not possibly be realized, since that concept was basedstrictly on fission product decay. ERDA especially objected to placing the priority for Runt cleanup ahead of Enjebi cleanup, saying thatit was their intent to givefirst priority to cleanup of potential residential islands; i.e., Enjebi. _—_-___