field was determined from experimentation in the laboratory with “spiked" sea water samples and in general was a double precipitation process in which most fission products were brought down in a ferric hydroxide scavenge. strontium were precipitated as oxalates. Calcium and The specific pro- cedures are outlined in the Appendix. Results. Results are presented in Table 1. It is to be noted that the values in this table are in terms of milliliters of water sample and that the disintegration rate is as stated and not in thousands as has been used in other tables in this report. scavenge" Also the values for both the "Pe (OH) 3. and the "Ca-Sr oxalate", even though small, have considerable reliability because the values have been based on large samples. The total sample activity was divided by the number of milliliters in the sample, which was 6,000 for The the pre-test samples and 500 for the post test samples. values for “whole sample" (post shot) were based on a 3-milliliter sample that was withdrawn vefore precipitation and hence would be expected to be less reliable. From inspection of Table 1 thefollowing conclusions can | be drawn. For the pre-test samples radioactivity of the Bogombogo sample was considerably greater than for other. stations. Why it was greater is not known, but activity of plankton samples was also greatest from this station. There were small but measurable amounts of activity in water samples from other stations. For the post test samples the amount of activity in the samples was closely and inversely related to | GINA MF At *