-47- An idea of the amount and distribution of radioisotopes in the North Pacific Ocean at the present time -- a year and one half after the last test series at Bikini-Eniwetok -- can be gained by again referring to the report of Operation Troll by Harley. One year after the 1954 series a two-month survey was begun near Bikini and continued westward to the Philippine Islands, then northward to Japan. The course of the vessel between Bikini and the Philippines was southwest, and again southwest, northwest a course that three times cut across the westward flowing North Equatorial Current. From the Philippines the course was southward a short distance to Morotai, northward to Japan. then Analyses of the sea water and plankton samples indicated that the radioactivity was of low level and widespread. The radioactivity in water from other than natu- rally occurring radioisotopes ranged from 0 to 570 disintegrations per minute per liter and in plankton from 3 to 140 disintegrations per minute per gram of wet sample. At the station with the highest value twelve samples were taken between the surface and a depth of 653 meters and the average of the twelve samples was 190 d/m/l. By comparison, the radio- activity in sea water from naturally occurring K49 is 736 d/m/l. The low the North values were beginning of the Equatorial found to be survey; Current, at east of Bikini the although outer this Atoll at edges of the was difficult to