-4i1- expected to pass to man via the marine food pathway, verification is required. We will first sample mullet again from the same islands sampled in 1976 during a different season. The fish will be dissected into tissues as before and analyzed for plutonium and other radionuclides to assess any changes in concentration that might have occurred during the intervening years. At two islands where fish are plentiful, a large variety of reef fish will be caught for analysis to insure that concentrations in mullet are representative of other edible species. As stated previously, it is impossible to analyze samples of the 600 species of fish in. the Marshall tslands from al! islands of the atolls. Thus we must restrict our evaluation to data generated from analysis of. the most representative species available. In addition, 24lam levels will be evaluated carefully to provide a complete transuranic assessment in marine food products. We will continue experiments to evaluate the generation of marine plutonium-labelled organic particulates resuspended by wind and wave action on the ocean-side reef at the atolls. Although no data were available for evaluation during a recent private conversation with a knowledgeable DOE representative, it was not at all encouraging to learn that a similar resuspension process might be generating small quantities of airborne marine plutonium aerosols at some coastal regions near Windscale. Because there are few regions in the world contaminated with levels of plutonium sufficiently high to be measured precisely, a continuation of this study in the Marshal! Islands is essential. Any positive results will require carefule evaluation. We have terminated sampling at some of the groundwater sites on Enewetak but, at the same time, are redirecting our efforts toward a more detailed assessment of the groundwater processes at our remaining sites. These include wells and locations containing usable freshwater as well as sites related to the agricultural experiments on Janet Island. This spring, storms permitting, we will drill additional test wells on Janet to perform hydrologic tests and measurements on the wells including dynamic pump tests, tidal response measurements, dye injections, and detailed sampling in these.and our other wells for chemical and radionuclide analysis. Soil from the well sites will be separated into size fractions and equilibrated with water to determine the distribution coefficients for plutonium and other radionuclides between the solid and solution phases. The purpose of these latter experiments is to evaluate the amount of plutonium that is selectively mobilized to solution from different soil types. : When ship support is available for Bikini, we will continue the studies begun in FY 1978. We also hope to initiate similar groundwater studies at Rongelap if ship support is available. Dye studies provided an estimate of the rate of groundwater movement that varies throughout the island and changes with season. Radionuclide groundwater concentrations are more variable at Bikini, but the reasons for these variations are not yet understood. Additional temporal experiments are needed to evaluate the radionuclide dynamics in the water.