~ Mr. W. J. Stanley tus =2- * December 12, 1979 We attempted some in-situ experiments in the lagoon to directly measure the flow of dissolved radionuclides entering the water column from the sediments. All of our efforts are related to understanding the persistence of long-lived radionuclides in the environment of Enewetak and Bikini Atolls to define and predict what future impacts the radionuclides may have on man using the environment. 2) Pelagic fish collection. One of the deficiencies recognized in our dose assessments was the lack of sufficient radiological data for representative pelagic species in the lagoons. We have, in hand, sufficient data for many of the reef species. This year, in conjunction with our other programs, a number of samples were collected from different regions of the lagoon to remedy this deficiency. 3) Lagoon water sampling. To understand how radionuclides move and migrate in any environment requires a knowledge of the basic chemistry of the specific radionuclide in the system. Last year a significant breakthrough occurred which allows one to differentiate between different chemical species of plutonium which coexist in seawater. Water samples from the lagoon and groundwater samples were collected to conduct this unique analysis to try to understand what environmental factors influence the oxidation state of plutonium in water at the atoll. 4) Groundwater groundwater both atolls quality and sampling. As part of our continuing studies at the atolls, samples were collected for analysis at several islands of to provide temporal radiological and chemical data on water to assess the migration of radionuclides first to the water table through the soil column and then to the lagoon. 5) A number of other ancillary experiments were conducted and samples were collected to study the partitioning of specific radionuclides between the soluble and the particulate phase in the lagoon water; tidal responses at specific wells; leakage of any radionuclide from the cript at Cactus crater; concentrations of radionuclides in some terrestrial insects; radiological quality at 3 new fresh groundwater locations established on Engebi; and radionuclide levels associated with cable on the lagoon fioor. One does not have to be a qualified oceanographer to recognize that none of the marine or groundwater sampling could have been accomplished in a reasonable amount of time without: 1) An adaquate smal] vessel with a shallow draft capable of operations anywhere in the lagoon and yet large enough to support operations for periods of time in remote regions of the lagoons with sufficient food and quarters for a scientific party and crew. 2) A stable platform that can maintain station position during sampling operations.