From a radiological standpoint the Eneu groundwater also looks good, and 137cg is not a problem. Although initially 90sy limits were exceeded in several wells, by 1977 all wells except FWR 6 had acceptable 90s; levels. Samples were collected in May 1984 for 90s, analysis, and the results when available should provide an up-to-date picture of radioactivity levels in Eneu groundwater. Groundwater data from Bikini and Eneu Islands are limited to only about the top meter of the groundwater body, and except for the most recent sampling period in May 1984, little data have been collected that define seasonal changes in the groundwater body. In order to make a reliable quantitative estimate of the groundwater development potential for these islands, additional data are required that better define the vertical, areal and seasonal distribution of groundwater. The extent and quality of groundwater on the smaller islands in the Bikini Atoll is not known at all. However, based on experience elsewhere in the Marshall Islands, it seems unlikely that any significant quantity of potable groundwater persists on these islands for any length of time, especially through periods of drought, because of their small size and the moderate amounts of rainfall they receive. To summarize, the amount of groundwater available for development on Bikini Atoll is not well known at this time, however, it most certainly would be limited. No potable groundwater is thought to exist on the small outer islands, and the salinity of groundwater on Bikini Island during periods of drought appears to be marginal for drinking purposes. From a radiological standpoint, Bikini Island groundwater does not meet drinking water standards. From both a salinity and radiological consideration, a potable groundwater body exists on Eneu Island. Its size is undetermined, but data collected to date suggest it may be capable of supplying the drinking water needs of a population of 200-250 during periods of drought when surface water supplies are not available. References Cited Emery, K.0., Tracey, J.I., and Ladd, H.S., 1954, Geology of Bikini and Nearby Atolls, U.S. Geological Survey Prof. Paper 260-A. McMurtry, G.M., Colin, P.L., Schneider, R.C., Buddemeier, R.W., and Suchanek, T.H., in press, Redistribution of Fallout Radionuclides in Enewetak Lagoon Sediments by Callianassid Bioturbation. Noshkin, V.E., Robison, W.L., Wong, K.M., and Eagle, R.J., Evaluation of the Radiological Quality cf the Water on Bikini and Eneu Islands in 1975: Dose Assessment Based on Initial Sampling, Lawrence Livermore National Laboratory Rpt UCRL-51879, Part 4. U.S. Geological Survey Memorandum to file, 1972, Water Resources Investigation - Bikini Island, Bikini Atoll, Marshall Istands. Von Arx, W.S., 1954, Circulation Systems of Bikini and Rongelap Lagoons, U.S. Geological Survey Prof. Paper 260-B. 5000061 A-6