30 Plutonium in the containment structure simply is net sufficient to sustain any significant increase in the level of activity in the of the lagoon. To take an extreme example, if as much as 1 Ci/yr Plutonium were being remobilized to the lagoon now, the average centration in the lagoon would increase only by 33 percent and the effective half-life of the plutonium in the structure would be years. Since the levels of plutonium in the waters of the lagoon have to be increased by several orders of magnitude to exceed inte national standards for drinking water, leaching from the dome is likely to create a hazard. An upper limit for the radiation dose caused by leaching from dome can be estimated by simply assuming that all of the transuran are rapidly remobilized to the waters of the lagoon (i.e., in at less than 30 years so that all effects would occur within one gene tion). As already noted, about 3 Ci of plutonium need to be remob lized annually to maintain the present concentration in the water column, and the estimated dose rate to bone marrow (for all transuranics) from the ingestion of marine foods is 0.26 mrem/yr (secti 5.5). If the concentrations of transuranics in marine organisms proportional to the concentrations in the water column (which is assumption behind the use of the usual “concentration factor"), the total additional dose from the remobilization of 12.6 Ci to th lagoon's water column should be approximately 4.2 times (12.6 divi by 3) the estimated annual dose due to the present concentration, 1.1 mrem. In other words, the dome at most could sustain the pre levels for about 4.2 years. This upper limit of 1.1 mrem for the total dose due to remobili tion of the dome's transuranics to the waters of the lagoon is ind pendent of the exact mechanisms by which it might cccur. A dose o mrem to bone marrow also is small compared to doses that can be expected from other causes at Enewetak. For example, cosmic rays the Marshall's produce a dose to bone marrow of 1.1 mrem every two weeks. Thus, even a relatively rapid remobilization of all the tr uranics contained in the dome to the waters of the Lagoon would no expected to create a significant new radiological hazard. A simple model can be constructed to estimate the increased 30dose to bone marrow through the marine food chain if leaching from dome to the lagoon took place with an effective half-life of T (see appendix A). If all 12.6 Ci in the dome were available for leachi and eventually went into solution in the lagoon (certainly an overl conservative assumption), the estimated increased dose as a functi of the effective half-life in the dome would be: Effective half-life Extra 30-year dose in dome to bone marrow (mrem) 10 20 50 100 200 400 1000 (years) 0.95 0.71 0.37 0.20 0.12 0.05 0.02