Comparison of spectra in various groups of people at Rongelap

Atoll in 1958 shows that there is littie difference between those exposed
in the 1954 fallout and those not exposed,

A small group of people who

moved from a non-contaminated island to Rongelap isiand only 2 1/2 months
previous to the present survey had less than one~-haif the ce? level and
less than one-third of the level of zn°> of the Rongelap residents.

A greaup

of 56 people who had been living, until a month before the survey, on a
slightly more contaminated island about ten miles to the north showed
slightly hisher cs? peaks than the inhabitants of Rongelap Island.
Because the 1958 data has not been subjected as yet to the thorough
analysis, the quantitative statements regarding the body burdens are pree
liminary.

However, on the basis of counts:smade with appropriate standards

corrected for absorption and geometry, it is estimated that the body bur137

dens of Ca

is 0.3-1.3 po and 1,0-3.G ue of zn*,

(The body burden of the

Rongelap people of cst? at 1 day after exposure in 1954 is estimated as

having been about 0.01-0.02 uc.)
The spectra of whole body gamma activity seen in 1957 and in 1958
of one of the Rongelap residents are compared in BPigure 4.

In both spectra

cai? arc zn®> are responsible for most of the gamma activity, but the 1953
levels of both are much higher than those seen in 1957.
is seen at 1.6 mev in the 1958 spectrum.

An additional peak

This peak was a prominent feature

of the background spectrum and has tentatively been ascribed to Lat*°,

It

is probable that the pat4°_,140 isotopic pair reaulted from fallout con —

tamination from the 1958 Pacific test series.

The ship containing the steel

room was slightly contaminated before proceeding from Eniwetok to Rongelap.!
7. The abdsence of peaks except at 1.6 mev and the fact that external procedures

such ag washing down the decks and removing contaminated deck paint definitely lowered the background inside the room (from about 70,000 cpm to,
about 25,000 cpm total counts) indicated that the contamination was outside
the steel room.

14

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