with assessing the residence time for specific radionuclides in the terrestrial environment. Groundwater and soil research studied should be conducted concurrently at the atolls. 7.) Enewetak Crater Disposal Site In September of 1980 a monitoring program of the groundwaters and near shore lagoon water adjacent to the Cactus Disposal site on Runit Island was initiated with the anticipation that the program would eventually be incorporated into the EMRDAP. As now established, groundwater and lagoon water is sampled every 2 months from each of 3 sites around the waste disposal crypt. Twice every year, oceanside reef water samples will be collected and analyzed for plutonium, 13705 and en Once each year local reef fish will be collected and analyzed for radionuclide concentrations. Any indication of radionuclides leaching through the aquifer and entering the lagoon will be assessed by comparing the results with historical data. These collections must be made repetitively over a period of years to evaluate the integrity of the waste containment system on Runit Island. 8.) Other Radionuclides and Pathways Although the major long-lived radionuclides in the environment and those critical in dose assessments have been identified, a continued search should be made to identify less obvious radionuclides and pathways which could contribute to the dose to man. For example, it was recently determined that N3mq is concentrated in the liver of fish from Bikini and Enewetak. Cadmium-113m is a low yield fission product, decays by energetic beta emission and has a 14.6 year 4)