67
6.13
Rongelap survey,
6.131
August 1958
Gross beta radioactivity.
Examination of
the gross beta radioactivity data in Table 2 shows considerable
variability between tissues and between habitats.
Comparisons
of the various classes listed in the table do not suggest correlation
with beta
general trends,
data:
radioactivity measurements.
however,
Two very
are evident from inspection of these
(1) beta radioactivity was present in detectable amounts
in all classes,
even in those instances where gamma radiation
was below the level of detectability; and (2) relatively high
‘
levels of beta radioactivity were generally coincident with
relatively high levels of gamma radioactivity.
These trends
suggested the presence of long-lived fission products which
emit primarily beta radiation,
induced radioactive transition
elements such as Co?8 and zn®5 which emit both beta and gamma
radiation,or a combination of both.
It is likely that radio-
active transition elements predominated as the source of most
of the beta radiation in the fish tissues analyzed, since fis~
sion-product isotopes have been determined to concentrate
mainly in the soil and land plants of the atolls, whereas the
induced,
non-fission—product isotopes predominate in the marine
environment
(Lowman,
Palumbo and South,
1957).
FF