-5)Decline rates vere calculated on 4 logarithmic basis by
the method of least squares using tne Nectar test as origin
excert for rets, whose radioactivity was referred to the Marcn
1, 1954 detonation at Bikini as origin.
The moat rapid de-
Clines with a slope of about -4% vere for sea cucumber nuscle
and integument at Leroy. At Belle the decline rates of sea
cucumber integument and muscle were about -2. Lagoon vater and
plankton near Belle declined at rates of -2.6 and -1.8, re-
spectively, Halimeda -2.1, green leaves of land plants -1.6,
Acropora after one month -2.2, clam tissues ebout -1.0, spider
oneit Siesues -0.6 to -1.2, land hermit crab tissues -] to -1.5,
sea cucumber tissues -1.6 to -2, fish tissues -1.2 to -1.9,
tern tissues -1.2 to -2.8 (gut), and rat tissues related to
March
l,
1954,
-0.8
to
-2.
(gut).
The residual long-lived products from earlier detonations,
particularly Mike on November 1, 1952, are considered to have
had an appreciable leveling influence on the decline and decay
slopes.
Even so, with the exception of clams, snails, and
crabs, the observed decline rates vere steeper than the -1.2
rate for mixed fission products.
Decay rates of certain samples were compared with the declines over simultaneous periods.
Decline rate was steeper
than decay for Halimeda, Acropora, and for most samples of sea
water,
plankton, and see cucumbers.
Declines approximately
equalled decays for island soil, beach sand, clam, snail, and
reef fishes.
Simultanecus data vere inadequate for comparison
of decline and decay for the green leaves of land plants, crabs,
terns, and rats.
Only with beach sand was the decay somewhat
steeper than decline.
The diluting influence of rain and of the surrounding
ocean upon the radioactivity in the vicinity of the testing
areas is constdered to be responsible for the cases of more
rapid decline than decay.
When samples of sea cucumber tissues collected in 1954-55
at Belle were recounted nearly simultaneously in 1957, the
ear)y samples tended to be more radioactive than the later
samples,
as would be expected when decline
ts more rapid than
decay.
Similar simultaneous recounting of samples of clam
kidney and spider snail tissues from Belle, where decline and
decay were equal, showed no significant iifference between early
and late samples.
Declines and decays of Halimeda and sea cucumbers vere more
rapid at Leroy than at more northern and eastern localities.