-31-
Table 16 indicates that during
oe
the time interval from about 50U to
1100 days post-Nectar, haif lives of
about ome year predominated even
among s@mples collected before
Bectar.
e
e
The one-year half life is
°,
ee
e
fe eee eee
CT eo
e
an
substantiated by gamma spectrometric
analysis on May 10, 1957 of plate
5797 (Pig. 23, curve 3) by Lowman
a
3
et aj. (1957:34), which showed the
redioisutopic
primarily
life, Mnd®
sonstituents to be
Rul06-Rn106
of 1-year half
sxorter than for shell.
long a period as three years.
ell (109) of the snail samples
Nearly
collected in 1954-55 were recounted
on May 21, 1957.
Figure 24 shows as log-log plots,
the radioactivity of snail samples
from Belle on May 21, 1957 related to
date of collection.
correlation exists.
Little or no
The amount of
activity remaining in May 1957 was
about the same in samples collected
on April 15, 1954 (shortly before
Nectar), shortly after Nectar, and
long (5480 days) after Nectar, thus
supporting the observation that de-
cline and decay do not differ.
°
.
°
8
fot
.
e
®
of
e
e
e
®
we
wm
The high levels of radioactivity
of Belle snails made it practical to
observe radioactive decay over as
to
:
oe
utes
e
e
»
e
ante
an
O8°
or
©
~%
—¢
me
than for visceral mass or gonad,
&
aoe OO
eM,
——
300-day, Cod7 267-day,
gut (P « 1%), and muscle (P about
5S), but not significantly longer
2«
eo
w—.
and small amounts of C00 5.2-year.
Using the t test, the average half
life for liver was significantly
longer than for mantle (P - 0.2%),
ee
-e
Be
e
a
—"
.
2!
e
.
e
a
+
weng ©
“aah
.
-=
oe °
.
=e
Wren
'e
-"
oe
8
.°
ae,
.
:@
.
.
e
°
-
.
gse
e °3
.
-*
e°
-
.
-
°
.
=e
.° e
whe
e
=
?
=-_
ete
“*" qe
@
apa
we
Pig. 2&
O- —