PERSISTENCE OF TRITIUM AND “C IN THE PACIFIC PROVING GROUND
to Cactus Crater and on Sanildefonso Island
near Mike Crater.
Macine oigauisiy were colectes at finer ce
cations within the iagoon. Fishes were obtained
near Igurin Island, Runit Island and off
Sanildefonso Island at the edge of Mike Crater.
Small killer clams were collected near Runit
Island on the reef. Two types of land crabs were
the soil particles (in this case, almos .
CaCO, and Ca(OH... wereohiained in.
ng tlie ireene-ury resiaques in a
containing copper oxide at 600-30u°C.
.
is collected from the effluent gasbya free,
and CO, by bubbling the effluentgas 4},
KOH. The extracted water was then anj!.
on Sanildefonso Island.
for tritium by either gas-countingorscintilt,:
methods. The tritium and “C determing.
were performed under contractby Isotope}.
of Westwood, N.J.
tions in the lagoon. A surface sample (—10 ft)
Units (T.U.). A Tritium Unit is defined as,.
obtained: the coconut crab, Birgus latro, on
Igurin Island and hermit crabs, Coenobita perlatus,
Seawater samples were obtained at two loca-
and a deep-watersample (— 180ft) were obtained
from near the deepest part of the lagoon, using
a polyvinylchloride water bottle. A seawater sample wasalso collected 1 m from the
bottom of Mike Crater. Rainwater wascollected
in plastic trays on Eniwetok Island in August.
The taxonomy of the plants considered in
this study is based on St. Joun.@)
Analytical procedures
All of the biological samples were analyzed
for loose-water and tissue-boundtritium. The
loose water of the plant and animal tissues
and the soil samples was extracted by freeze
drying at 0.1 « of vacuum. Raney) demonstrated that freeze-drying plant tissues was
equivalent to oven-drying at 105°C for 24h.
The analyticalresults are expressed in Tri: .
atom oftritium per 10?® atomsof hydrogen a..
therefore, is an expression of specific actiy:.
The tritium content of the samples wil) ,
reported in T.U. for loose- and tissue.,,
minera]-bound water, and the MC is expressed.
the percentage of “C above that of wood(fro~ ’
the year 1890) which is equivalent to 0.95 of 1.
National Bureau of Standards oxalic acid 1 ,
standard.
RESULTS
The analytical results of the plant and ,,
samples from seven islands on Eniwetok Aw, |
are given in Tables 1, 2 and 3. Data in thee .
tables are presented as an ecological seris ;
representative of the habitats being studied
The wood, leaves, litter and soil from singh |
Table | contains the tritium valuesof plants and
and protoplasmic water, and loosely held water
of hydration in the cell walls. Because of the
Table 2 lists the tritium content of plants anda
various complex states in which wateris held in
plant cells, it is probably more realistic to
consider this water as cryo-sublimed water than to
attempt to describe its exact physiological
het
wins
enitet
wood
Messer
paemidia
at genta, ,
Masset
y hmidia
argenled,
is, end
of Runit
Scarvola
rulescens
Lplurus
repens
Triumnfet
procumbe
a
* (sec
¢ Sec
soil sample from Engebi and Sanildefonso Island,
adjacent to Mike Crater. Table 3 containsthe
tritium values for plants and soils from those
islands which were not intimately associated
with the Cactus or Mike Shots. These samples
were mainly wood, but a complete ecological
series was collected on Japtan Island.
Duplicate samples were also analyzed to
100-110°C. Plants are generally able to extract
water from soils at tensions up to 15 atm or
about 50 w of vacuum. Therefore, the water
freeze dried from soils (and defined here as
loose water) may represent more than that
actually available to the plant.
The tissue-bound water of the animal and
plant tissues, and the mineral-bound water of
methods and to determine the variation present
within a single sample collection. A duplicate
sample of water from the bottom of Mike Crater
was reanalyzed | monthafter the first analysis,
and the sample was stored in glass between
analyses. Four duplicate wood samples were
analyzed. The wood samples had beenelectrically sealed in double polyethylene bags (6 mil)
and kept at below freezing temperatures between
provide an internal check on the analytical
wu
hygroscopic water. Hygroscopic water is removed from soils by oven drying for 8-10 h at
egies
a soil collected at Cactus Crater on RunitIslan.
The loose water obtained by freeze-drying
soils is all of the capillary water and most of the
nature.
Mavde
» pends
sampling station make up an ecological serig
Loose water of plants extracted by cryo-sub-
limation representsall interstitial water, vacuolar
sample
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