f
coconuts. Wide variation in levels among samples from the same island
can probably be accounted for in terms of age of the nut, age of the tree,
humus content and pH of the soil in which the tree grows, and a number
of less important factors such as depth of island profile and density and
type of plant growth around the coconut tree.
Since arrowroot grows in the contaminated soil, most of the
factors affecting coconut uptake had little influence on the arrowroot
uptake, For this reason the arrowroot samples showed relatively little
variation among specimens. Also, the growing season of arrowroot
had apparently ended and only mature cormscould be obtained thereby
specifying the development stage of this food material.
Since pandanus and breadfruit trees bore very little fruit at the
time of the survey only sketchy sampling was possible. Both of these
trees tend to shade out competing plants and develop fruit rather rapidly.
Thus, soil variation was the main factor causing differences in uptake of
activity for samples from the same area. As expected, less variation
was found in the pandanus and breadfruit than in coconuts but more than
in arrowroot samples. Papayas were found only near native habitations
and apparently were cultivated to a greater degree than the other major
food plants. This resulted in a system comparable to the pandanus and
breadfruit.
2.2.2
Miscellaneous Plant Samples
A summary of the gross beta activities found in miscellaneous
plant samples is contained in Table 2.2. Data in this table are on the
basis of wet weight.
The grass samples are of general interest because of their similarity to the forage crops and cereal grains responsible for the major
portion of the world's food supply. Likiep, Utirik, and Bikar samples
indicate that grass may act as a sensitive indicator for radioactivity
available to plant uptake. The age of the grass and the soil characteristics are probably responsible for the wide range of activities observed
for samples from the same island.
“Native Marshallese were included in the survey teams,
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Plant trunk and foliage samples indicate a considerable movement of activity into the plant system, as was forecast by the presence
of activity in coconut tree sap run during the course of the original
study.* The coconut tree system is especially interesting since the total
activity represented by the fruit is a small fraction of that which is
residual in the remainder of the plant. It is unfortunate that the survey
was made when coconut tree sap ("'Jugaroo'") was virtually unobtainable
even by native Marshallese,” Use of this material as food for infants
makes it merit study from a contamination standpoint.
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