of the terminal point vith respect to the regression line.
In
63 of the graphs the last point fell below the line and in 53
cases, above. Phe position of the last decline p°int was predominantly above the decline regression line for beach sand,
Belle land hermit crebs, reef fish, and Janet rats.
It might
be suspected that for these organisms declines vere leveling.
The terminal points vere predominantly below the lines for sea
water, plankton, clam, sea cucumber, and tern.
Aesuming a constant, linear, log-log decay rate, and an
equal rate of decline, a11 samples regardless of vhether collected shortly or a long time after detonation should give the
same level of activity when counted simultaneously, since the
early samples would have decayed to the level of the later
If the linear log-log decay and decline rates differ, then
the early and late samples should yield different values when
counted at the same time.
When analogous samples taken on
different dates vere counted simultaneously, their levels re-
flected the relationship between decline and decay. This
relationship was evident for Belle sea cucumber integument where
the decline slope of -2.0 differed from the decay slope of about
-1.4 by the amount of the recount slope, -0.6 (p. 33).
Por Belle spider snails and the carapace of the land hermit
ecrabd no difference was apparent between decline and decay, nor
was there a trend in the recounts (p. 25 and Held).
Rapid decline and decayat Leroy
The steepest decline and decay slopes for marine organisms,
represented by Halimeda and sea cucumbers, were at Leroy. Rapid
decline might be caused by dilution from ocean currents that are
relatively free from radioactivity, but this factor would not
influence decays.
In view of the correspondence between decline and decay,
the rapid decline at Leroy undoubtedly reflects the ftsotopic
composition of the samples rather than any diluting effect of
ocean currents.
However, some selective transporting mechanisn,
probably the vater currents of the lagcon, must have been re-
sponsible for bringing shorter-lived products to Leroy or
removing long-lived products.
That ‘he Nectar-derived short-lived products at
Leroy were
not contrliuted by fallout its confirmed by the slow rate
decuy of soil from the island proper.
a
of