145° 1 150 of 165 Mc 26 160° 165° 5 5 [55 ss | 36 oF |< Fos He 2 10 ef sf da oF a7 PP Es PP s-yy af oof oP 6 sf ze 30 oD i wu 4 33 43 53 “ge : I MMMdade) aidan ald 4 Peer FOOee eae Sh DEPTH IN METERS 25= 100 —— 63 73 150 Y SH GOQ ACTIVITY Fig. 6 Collection stations of the Marsh survey (top) and the relative radioactivity of the wate (filter and filterable fraction less K*°) at each depth sampled. Maximum value at eac station taken as 100 Troll Report (7). However, in the area of the Marshall Islands and as far,wes as Guam this dispersion does not occur within 6—8 weeksafter contaminatio of the water mass. According to samples taken during four different survey in 1956 and 1958 the radioactive material was not uniformly distributed in th mixed layer. In samples taken a few days after contamination and 6 week later, the ratio of the radioelements in the particulate matter to those in th soluble-colloidal form varied throughout the upper mixed layer (Fig. 4). Als the total radioactivity in the water varied throughout the depths abovetl thermocline (Fig. 5). The values illustrated in these two figures are averages « all stations sampled and show only overall trends. The lack of homogeneit within the mixed layer was even more marked at individual collection station (Fig. 6). 114 7 i oa