-23-
. reported
Thus, it seems desirable to report radioactivity of plankton on an
ty be com-
ash weight basis, even though other organisms and substances might
g to drain
more desirably be considered on a wet weight basis.
preparing
Figure 8 shows the trend of radioactivity in the plankton samples
rganisms
from Rongelap lagoon (from 1954 through 1958) related to time, using
n being
a log-log plot of the beta activity on an ash weight basis as determined
2re based
with a methane-flow counter.
wet plank-
dotted line showing a decline slope of -3.5 was fitted by inspection to
*educed to
the minimal points near 300, 600 and 1500 days, points removed as far
Data are from Tables 3 and 4.
The
as possible from the peaks caused by the Redwing and Hardtack series
Ire con-
of detonations.
2s between
The maximum level of the lagoon plankton a day or two after March
iS, as seen
l, 1954 may be conjectured by extrapolating back one cycle on Figure 8.
es was only
It appears that maxima must have been at least 20, 000 uc/kg of ash.
elap Island,
Further reference to Figure 8 shows that the original detonation,
iniwetok
Bravo, must have contributed 100 times as much activity as the Redwing
' wet basis.
series, and Redwing 20 to 100 times as much as the Hardtack tests.
ilinginae
The decline picture is characteristic in its pattern.
r than in
the fallouts, followed by steep declines until the next fallout.
tivity per
ception appears in the region of Kabelle Island in late 1954
nae levels
1956 to 1957.
(Table 3).
Rises result from
An ex-
and
from
|
Figure 9 shows, on log-log plot, the decay patterns of six samples
counted on more than three Occasions.
Ordinal values on the vertical
ye
POR supe gE