CHAPTERIl
Gross Activity
A. Land Plants
The high initial activity of the “edible plants”
(Graph 2) was probably due to surface contamination caused by the direct fallout. The rise
in activity after ayear after the fallout occurred
Graphs 2 and 3 indicate the general levels of
activity of edible plants (pandanus, papaya,
breadfruit, arrowroot), and coconut meat and
milk at Rongelap Atoll together with their
decline of activity with time.’ ?
may be due to (a) sampling and counting vari-
ances, (b) the ability of some plants to concentrate Cs" (see Section Radiochemical Analysis), (c) the increased availability of the
radioactive fallout material to the plants, or(d) a
combination of these factors. Initially the activity in the coconut milk and meat was less
than other edible plants, but the rate of decline
of activity has been less than for other edible
land plants due principally to the higher percentage uptake of this longer-lived Cs'*’.
Tables 1 and 2 show the analyses made by
NRDLfor their first survey in February 1955,
Table 3 is based on the February 1956 survey.*
Tables 4, 5 and 6 show the analyses by
HASL.*: 6
Table 1—Summary of Gross Beta Activity in Miscellaneous Plant Samples*
AVERAGE ACTIVITY (uc/g x 108} ® >
PLANT MATERIAL
ISLAND
Likiep}
Utirik
Rongelap} Busch
Eniaetok Labaredj|
Grass... -.....--------.--.-20
400
3000
42)
Coconut leaf_..--.--.-------]-------W000
[Leet
Coconut frond stem...--_.-.]--...-..|-..----2--[.-22------|-----2-|---- eee
Coconut shell_._.-_------2---| 22-2] ee) fee]
Coconut huskE...-....-.-..-17
1.5
63 j_-- 2-2}
Coconut sprout.....--------]-.------]---- 22-22.
be
Sprouted coconutroots-----|_..-----]-----2-..72 |_.------|----- ee
Scaevola leaf..-..-.--.-.----|--------|.---.----.|.----..--_}-.- ee}
Scaevola trunk section ._.---|--.-...-}--.-..-.--{.-..---__f-------_}-----_-Arrowroot stem_..-.-.--.---f--------]----2-- 2.
19 |_.--_-..]_--_.__Arrowroot leaf. _..-..-------|--------|.------_-6] |---..--.|-------PumpEin.-....--.--.------2.0 |---------35 |__| eee
Limes.....-..-.--.---------20 [elf ef fee
Taro..-__.-..-.---------.--1.1 fo. ee eee} eee
Banana. ..-....--.----.---.4.6 |--------2 2}. ff
Vines_-__..--..--.----.-----|--------|---------- [222 ]e eee fee
EKabelle
Luknen
5300
1900
2100
750
1800
670
Gejen
68, 000
Lomuilal! Bikar
5600
|Eniwetak
180
400
f__----- |e te ee fe eee ee
wee ee nnn n| nee eee ne
140 fw. fod] -owen e een ee
17 |_--.-----160 |_..-.---~-]------~-]----+--.-wece ween
73 |---------110 |--.------8.4 |---------ween ee neee
110
|_--..-----|-------. |---| ee] ee
wee ene e eee
740 |_.....-.--|-.--.-..--]----------|--------]--------=+
wenn ene
120 j---.---.-100
290
6.7
il
ween wee nen} eee noe eee nee eee ee fee - eee
23
een e neces
wee ween owe een | nee eee
490 j.-..-..-..]-----
340
= Wet weight.
> As determined on basis Us0+« standards and empirical scattering and absorption corrections.
*Collections made about February 1, 1955. Data reported as of March 1, 1955.
5
LOE Akoii.
|.