Planning for the decontamination and rehabilitation of the atoll was in progress during conduct of EXPOE. AEC recommended restoration on Sally be delayed for execution concurrent with cleanup. This plan was acceptedby all concerned parties and was accomplished during the spring of 1979. Significance to Radiological Characterization. The programs of PACE | and EXPOE produceddrill holes and test wells which proved to be valuable assets for a later program designed to gain understanding of the radionuclide and groundwater dynamics of a coral atoll. Several of the early exploratory holes, and some added to the inventory at the request of the AEC, are still in use for ongoing water lens studies. Among other things, these studies explore the rate of movement of radionuclides through the soil above the water table, and the rate of dispersion of radionuclides within the water lens. Both of these phenomena are significant to computation of long-term radiation dose to individuals utilizing the islands of Enewetak. Radiological reconnaissance conducted as part of the PACE site selection indicated that no significant radiological hazard could be expected in the designated area on Sally. However, actions taken in support of PACE 2 introduced an added level of complexity to the task of compiling a radiological characterization of Island Sally. The concentrations of radionuclides in the surface soil removed from the 19-acre test bed, and on the surface of the 10-acre dump site, are unknowns. The inference can be made from available information that the brush and surface soil from the 19-acre area may have been put into the saltwater pond first. The last overburden soil to be removed, and presumably the least contaminated, would have been placed on the top of the 10-acre area. Soil sampling for determination of radionuclide concentration of the surface that existed prior to dumping in the 10-acre area would be imprecise, at best. During the process of refilling and grading of the excavated area, most of the 10-acre mound was pushed back by bulldozer. Radionuclide concentrations that did exist in the PACE 2 area have been thoroughly mixed and dispersed by the original soil movement and subsequent restoration activities. The 86 trenches that were dug by backhoe on various islands, then refilled, present the possibility of generating anomalous data during later characterization efforts. Soil samples could, by chance, be taken from the spot where a trench had been dug. Such a spot would not be representative of the surrounding area due to the mixing of soil that would result from digging and refilling operations. 1.5.3 Mid-Pacifie Research Laboratory (MPRL) The Enewetak Marine Biological Laboratory (EMBL) began operations in 1954 under the auspices of the Division of Biology and Medicine of the U.S. Atomic Energy Commission. It was and is operated by the University of Hawaii, currently under contract to DOE's Nevada Operations Office. Until 1975 the laboratory was run as a part-time field station visited and used by a variety of investigators. In 1974, the AEC decided to expand laboratory operations to a year-round schedule, with corresponding increases in laboratory personnel and support staff. The lab was re-named the Mid-Pacifie Marine Laboratory (MPML). (In the same year the spelling of the atoll name was changed to Enewetak,to reflect the pronunciation and meaning of the name as used by the Enewetak people.) The laboratory name was again changed, to the Mid-Pacifiec Research Laboratory (MPRL), in 1979. These name changes were intended to reflect a broadening of the laboratory's role as a center for research on all aspects of atoll ecosystems. Research supported by the laboratory was chosen by an advisory committee which evaluated written proposals covering a broad spectrum of marine and terrestrial science. Studies involving the biological effects of radioactivity received some attention during the early years but, in general, studies have become quite diverse during the past decade. The scope of research projects can be reviewed in NVO-628-1 which contains reprints of 223 papers generated from Enewetak-based research during the period 1954 through 1979. During the planning for the cleanup, the preparation of the Environmental Impact Statement and the cleanup itself, the laboratory assisted with baseline information and advice on a variety of subjects and issues. 19