~5without completely dissolving the soil.
Present evidence leads us to
believe that the acid leach renaves 85% ar more of the. Sr-90 and the
electrodialysis at least 75%.
Some early analyses.were obtained by
emmonium acetate leaching of the soil, but this method is now felt to
be inadequate and none of the data presented here were. ohtained in this
Way»
The chemical analysis following extraction requires separation of
the Sr-90 from the inactive bulk constituents of the extract and fron
other radioactive isotopes, which include the natural constituents of
tae soil and other fission products, including Sr-89.
The major advantage of a soil semple is that it represents the
accumulation of Sr-90 at a particular location at the time of sampling.
Experimental work has shown that the movement of. Sr-90 in the soil is
slow enough that adequate samples can he obtained... For exemple, fron
75-80% of the Sr-90 found in the soil is in the top two inches.
‘The
disadventege of soil samples is in the complex end_time consuming nature
of the analysis.
Sea Vater Semples
Since approxiretely two-thirds ofthe earth's surface is covered
by the oceans, & complete accountingfor Sr-90 deposition recuires
sempling of the oceans.
However, in contrast to soils, the Sr-90 in the
ocecns is distributed through a depth of several hundred feet, et least.
The enelyticel requirements for this type of sample have been beyond the
cupebilities of the participating laboratories except for samples taken
near the Pacific Proving Grounds shortly after a major veapons test.
Therefore, studies of distribution in the aceen have been limited to
meccurenents of total fission products end their trensport by oceen
lan
DOEARCHRs
Ge