12 other radionuclide concentrations in mullet collected from 13 different islands of Bikini and Enewetak Atolls (No 78b). Representative lagoon water samples were also collected for analyses. Concentration factors for plutonium in the organs and tissues of mullet were computed from the analytical results (No 78b). Excellent agreement was found between predicted and measured concentrations in fish at Bikini using only concentration factors generated from Enewetak data and the measured water concentrations at Bikini. The average concentration factor for plutonium in wet mullet bone was 139 + 54 (No 78b) and the average concentrations of plutonium in the muscle, skin and gill tissues relative to the bone were 0.19, 2.6 and 6.2, respectively, on a dry weight basis. Using these relative values, the average measured Kwajalein lagoon seawater concentration of 0.54 fCi/l, and the wet/dry weight ratios in Table 2, we estimate that the wet Kwajalein mullet bone and skin tissue should contain 2394240, concentrations of 0.075 and 0.21 pCi/kg, respectively. The measured concentrations of plutonium in these tissues were 0.072 and 0.29 pCi/kg. The close agreement between the measured and predicted values indicates that there is a great deal of validity in the concept of a concentration factor and we feel justified in applying this predictive model to estimate the mullet muscle and gill concentrations at Kwajalein. We estimate that the muscle and gill concentrations should have been 0.0034 and 0.12 pCi/kg wet weight, respectively. . Recent measured concentrations of plutonium in coastal California Rockfish (Sebastes sp.) muscle and bone (No 78c) provides additional support to these arguments and suggests further that there may be little yee bs DOE AB: rt ys! hay