-k07- program. Since the Liktanur is out of operation, we had scheduled a trip to Enewetak in late January 1978 using island support. However, a local storm damaged many aspects of site operations forcing us to reschedule this trip to March 1978, In FY 1975 we initiated detailed radiological studies of the hydrology and groundwater geochemistry at Enewetak and Bikini. These first detailed investigations of their kind at the atolls, have given us new insights into the transport mechanisms and cycling rates of radionuclides between the terrestrial and aquatic environments. The circulation and redistribution processes of plutonium and other radionuclides are investigated by interpretive analysis of radiochemical and physical data from the lagoon environment. Plutonium levels in the environment and organisms are being compared to distribution in species and environments that receive plutonium from other sources, including world-wide fallout, reactors, reprocessing facilities, and Thule. Biological samples are carefully analyzed to determine the radionuclide distributions in body tissues and to calculate the relevant concentration factors. 15. RELATIONSHIP TO OTHER PROGRAMS: The Enewetak and Bikini groundwater programs are carried out in close cooperation with R. Buddemeier (University of Hawaii); Buddemeier is conducting a program to investigate the cycling of the major elements and nutrients in the groundwater. Data generated from his studies have been helpful in our interpretation of the radionuclide cycling in the island groundwater, There is also a close relationship between the groundwater and marine studies and the LLL agricultural experiments (Marshall Island Radioecology, 189 No, LLL/ASEV-80-63) and assessment program. The loss of the R.V. Liktanur forced us to modify our field efforts for this next year. Presently we are exploring ways to coordinate our program and the agricultural project to fulfill program requirements at the atolls with minimum ship-time support. The advantage in dollar savings is obvious; and it requires now only to work out problems related to logistics. Our programs provide significant data in support of the rehabilitation efforts at the atolls. We have provided data and assessments relevant to cleanup operations at Enewetak and will continue to do so whenever our data are needed. Last year, we fulfilled DOE-DNA requests for information related to the disposal of the remains from the multistory structure on Enjebi, the impact of soil disposal! on Northern Runit and the marine environment, the radioactive hazards created by removing underwater cables from Enewetak, the establishment of a meaningful sampling program for the proposed multi-atol! survey, and the review of plans for plutonium cleanup at Enewetak Atoll.