33 34 disposal methods for transuranic wastes to the oceans are discussed. Some massive corals collected from the atolls contain well-defined growth bands dating from the collection time to the early 1950s, Each yearly growth concentrates plutonium in proportion to the levels in the environment (No75, No78a). Concentrations of 2394240), associated with growth increments dated since 1965 in three Enewetak corals from different locations in the lagoon and one Bikini lagoon sample are given in Table 7. The average amount of plutonium concentrated by the coral from 1965 until the year of collection is computed and shown in Table 7. The average absolute concentrations in the corals are different as expected, and reflect the local environmental concentrations in the region. These results from coral and other studies demonstrate that Enewetak lagoon has attained a chemical steady state condition with respect to plutonium remobilization from solid components to solution. Not only will the simple equilibrium model explain average concentrations in lagoon water, but it can be used to estimate local concentrations expected in the waters from areas of the Atoll with different levels of contamination. By using appropriate concentration factors for plutonium, the quantities accumulated by marine organisms anywhere in the lagoon can be estimated. The data on biotic concentration can be used to estimate the potential dose to man if part or all of the Atoll were to supply his marine food requirements. In only a few growth sections are the 23942405, concentrations different from the mean by more than a factor of two, and only coral 1 and 2 show this magnitude of variation, Corals 1 and 2 were obtained in the water on the lagoon side of the eastern reef. The patterns of current in this region of the lagoon are variable, and the windward reef community contributes a significant detrital load with associated plutonium to the lagoon. Since growing coral is a point source in the environment, small changes in even the local circulation, to name one of many factors, will greatly alter the plutonium concentration in the vicinity of the coral. ACKNOWLEDGHENTS The author wishes to express his appreciation to several coworkers, K, Wong, R. Eagle, R. Spies, K. Marsh, T. Jokela, J. Brunk, G. Holladay, and L. Nelson for assisting in providing much of the previously unreported data and without whose efforts in the field, our program in the Marshall Islands could not be carried out. supported by the Division of Biology and Environmental Research of the Department of Energy, Contract No. W-7405-ENG-48. It is rather more surprizing that, for the most part, the 2394240), levels associated with the last 9 yr of growth are nearly constant, which shows that the dissolved 2394240, levels available to the corals in a specific region have also been similar during the last 9 yr. This work is « ats we ?a