a ws CHAPTER 6 SUMMARY 6.1 CONCLUSIONS ; Significant amounts of beta and gamma activity were found in the tissues of Marshall Island fish and marine invertebrates collected one year following exposure to the fall-out from Operation CASTLE. The highest concentrations of internally deposited activity was found in marine specimens taken from the northern Rongelap lagoon; lower concentrations of internal activity were found in specimens from the south- ern lagoon. The crabs, clams, and snails contained considerably higher concentrations of radionuclides than were found in the fish from the Same area. Most of the activity in the marine specimens was contrib- uted by Zr%.Nb® and Ru! Rh! There was no fractionation of Sr®9.Sr™ in the tissue of the fish analyzed. won Residual soil contamination was primarily contained in the top several inches of soil with movement indicated down to the lens water. The activity is being slowly leached off the islands by ocean tides. The major radiunuclide found in the land food plants and in the tissues of land animais was Cs}3"_ The lagoon environment contained principally rare earth group elements, Ru!$_Rh!% and Zr3_.Nb%, Radioactivity was found in all food plants on the contaminated islands. Supporting plant systems also contained a large reservoir of activity available for future incorporation into the plants. The amount of activity in the specimens analyzed was generally proportional to the external gamma reading in each of the areas. 6.2 COMMENTS ON FUTURE WORK In the event that future work is carried out along the lines initiated during this project the following suggestion may be helpful. DOE ARCHIVES -27- 36