annual quantity of plutonium entering the lagoon with groundwater. The plutonium in the lagoon water immediately east of the crater, will then increase in proportion to the quantity of plutonium in the crater fill. However, fixing the soil with concrete will lessen the immediate impact on the marine ecosystem since we feel that this procedure will retard leaching or remobilization rates. On the other hand we cannot assess how long the concrete mixture will last when it is in contact with sea water for hundreds to thousands of years. To further minimize marine prebiems associated with crater fill, it is recommended that if the crater is filled, the fill be composed of the lesser contaminated soils from other islands. The more contaminated soil should be disposed of on the ground surface of Runit. The marine impact scales directly with the total quantity of plutonium disposed of in the crater. The concentration of Pu in fish from this new source and eventual dose to man via the marine pathway will again scale proportionally with the quantity in the crater which contributes in part to the quantities found in the water in the local off shore environment. . The least impact from plutonium (discussed in the previous section) on the Runit marine environment would be to eliminate crater disposal and place all relocated soil on North Runit Istand as a soil-cement mixture. If the freshwater impacts can be reduced, the material could be capped to further reduce plutonium impacts on the marine environment. 3. Some Additional Considerations: A. The magnitude of the Pu doses discussed above are calculated using the most current dose models and the presently accepted