11 Plankton Data The high specific activity of plankton compared with sea water makes it a simple measure of the distribution of activity (see Figure 9). It is not completely quantitative; the amount of water swept out is not accurately known, nor are the source and history of any sample known. However, thereis definite correlation between the macroplankton and sea water samples. A comparison between the results obtained on corresponding samples of macroplankton measured at the Applied Fisheries Laboratory and HASL is shown in Appendix F, [ Table 2 Macroplankton Activity Based on one gram wet weight Total No. of A few samples of microplankton Ave Station d/min Samples d/min/g OA-3A 4-154 170 740 7 24 24 31 17-214 22-274 28-31A 32-33A 350 615 288 220 10 ll 7 4 39-40A 48 92 10 3 7 2 3023 85 16-16A 34-3B8A 41-444 45-464 111 379 2 8 Statistical tests show the two sets of values to be indistinguishable, Comparison of Troll samples with comparable samples from other areas is shown in Appendix I. 56 35 56 4] 55 47 16 3 5 35.6 were taken with a 17-cm No. 20 net dragged from 20 m to the surface. These samples showed even higher specific activity than the macroplankton, as shown in Appendix G. A breakdown of plankton samples by current region is shown in Table 2, corresponding to Table 1 for water samples. The only marked change is the drop after Station 38A; it corresponds more : . os closely to the change in surface activity than the depth activity. Radiochemical analysis of the plankton showed 80-90 percent of the activity to be Ce!44 with its Pr144 daughter. The remainder was chiefly Sr?99, but small amounts of other isotopes may be present. cs!37 should be retained in the procedure, but was not detected. Fish Data None of the edible portions of fish collected on Operation Troll showed activity levels that would be of concern. In addition, the activity levels were so low that radiochemical analyses were not possible. The controlling activity in the hazard from mixed fission products is the §r90-y90 pair. The maximum permissible level for food may betakenas that for drinking water, 8x1l0-? Lc Sr 90_y90 per milliliter or per gram. This is equivalent to 2x10-5 pc MFP/g at one year, or 45 d/min/g. For populations, the maximum permissible level is con- sidered to be 1/10 of the industrial level, or 4.5 d/min/g. Thisis about 500 d/min/g of ash, the basis of reporting used here. For the analyses of fish reported in Appendix H, the maximum activity found in tuna muscle was 132 d/min/g ash. However, these analyses were in error due to incomplete removal of potassium. Table 3 shows comparative values of shipboard and laboratory analyses for mixed fission products. The maximum values from the laboratory measurements for tuna fish are 3.5 d/min/g ash, or less than 1] percent of the conservative permissible level. ot ay Bek