Lagoon Dredging of Sediment. Dredging of lagoon sediments as a source of replacement soil for both topping and excavation alternatives is less desirable for several reasons. The dredging operations themselves could lead to major ecological damage and outbreaks of fish poisoning. Dredging would be expensive and the sediments themselves would not be particularly valuable as a soi! because of low nutrient and high salinity levels. Thus, the sediment would have to be leached of seawater, fertilized, and conditioned. Furthermore, there was some question whether the potential sources of lagoon sediments themselves would be clean and relatively free of radionuclides. At this time, it appears that dredging offers no clear advantages over other alternatives and the high elevations of the two main islands seem to preclude the need for replacement sediment to maintain the present geological stability of the islands (See Peterson, Appendix A). COMPARISON OF ALL ALTERNATIVES A comparison of the enviromental effects of all alternatives is presented in Table 2 (See Summary) and includes a ranking of alternative from "best" to "worst" from an environmental perspective and a list of potential measures to reduce or avoid adverse impacts. In general the nonstructural alternatives would have the least environmental effects, but are not as effective as other alternatives in avoiding the risk of soil contamination. Excavation alternatives would be the most effective in eliminating soil contamination but the environmental effects are greater than for other alternatives. However, the effects of some of the excavation/disposal alternatives should still be acceptable and feasible including: lagoon crater disposal, disposal on Nam Island, and expansion of Bikini Island. If feasible and sufficiently effective, chemical treatment, washing, and topping would be environmentally preferred over excavation alternatives. 5. ENVIRONMENTAL CONSEQUENCES OF PROPOSED ALTERNATIVES TO REHABILITATE SOILS AT BIKINI ATOLL. A. GENERAL. Tne environmental consequences of all alternatives are summarized and listed in Table 2. The impacts are divided into two categories: unavoidable and avoidable. For the latter, a list of potential measures to reduce or avoid impacts is also included. The analysis of possible impacts is confined to actions directly or indirectly required for the rehabilitation of the soils. Other actions required for a successful resettlement program, such as housing, transportation, utilities, etc., are not being addressed by the Committee at this time. Hence, there is no discussion of the impacts of these other activities in this environmental assessment. However, all aspects of a proposed Bikini resettlement program should eventually be addressed in an Environmental Impact Statement when and if the decision is made to proceed with the cleanup and resettlement of Bikini Atoll. In light of the above, the alternatives not involving soil rehabilitation: (delay resettlement; allow resettlement but only control diet; or allow the first stage of phased resettlement) will not result in major adverse environmental impacts. If phased resettlement is implemented which eventually leads to the rehabilitation of soils on Sikini or otner islands, then this subsequent phase would result in environmental impacts, depending upon the soil rehabilitation alternative » selected. The impacts of these alternatives. are highlighted in the remainder of this sectidaf} 54 | LS E-12