ConairWINCLASSIFIED.

Apprehension of Long Range Yontamination of Japan and its

Fishing Grounds

Japenese apprehensions over the posibility of long range

radiologieel. contamination were very similar to those we en
countered in the United States as a result of NPG operations.
A difference in Japan is due to the fact thet none, if any, of

the counting equipment is calibrated, Gi tubes are used without shields,
and under conditions where the background count is apt to be highly variable.

This, ccupled with the fact thet they do not know the background activities
of such things as soil and biological materials, makes it very difficult
to evaluate the reports. NMeny of the reports of "ash" falling in verious
parts of Japan are undoubtedly dust or soot falls thet occur normally in
any industrial crea from time to time. Reputable scientists have examined

samples of potassium-rich soil and have reported their date is gross
counts without any reference to normel soil background. For this reason
I find it very difficult to take serious the frequent public report of
50 to 100 counts per minute for the unspecified size of samples reported
from time to time,
At my conference with the Japan scientists and government officials
on March 24, I explained the procedures we use in the Stetes for
measuring fallout. I urged them to use similar procedures for the

sake of uniformity and offered to loan them the equipment we used, They
secmed eager to accept and I requested 4 sets of equipment which has
since arrived from the States, However, since the arrival of this
equipment, I have deleyed giving it to the Jepanese because in their
present state of mind little good could come of it. I do believe,
however, that when the present confusion subsides, it will be useful

for the Japanese to maintain a fallout monitoring network end I think
we should cooperate with them to the fullest extent.

In a conference with Dr. Kobayoshi on March 26, I informed him of
my conversation withDr. Bugher and his offer in behalf of the Atomic

Energy Commission to provide financial support for marine biclogical

studies directed at the long range contamination of the Pacific,

Dr.

Kobeyoshi, through his interpretor, expressed his appreciation for this
offer but did not pursue the matter further and has not approached me

since.

With regard to fallout on the Japanese isiends themselves, it is to
be remembered that the position of those islands in relation to possible
sites of weapons testing is such that the Russian testing program is ept
to produce more fallout than events in the Marshalls or Nevada.
Estimating the Whole Body Dose

I doubt that it will be possible to make a satisfactory estimate of

either the Beta or Gamma dose the fishermen received. We know that the
ash fell in such quantities that the deck of the ship became white, and
there was sufficient material to develop visible footprints. Unfortunately,

this is the limit of our information on how much ash fell end how long

it remained on the ship. The fishermen washed the decks in order to remove
the ash and according to their reports their washing was effective. ‘hen
the vessel arrived in Yaizu much of whet remained was removed.

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