same period; however, liver tissue decay and decline rates are similar.
The differences in rate of decay and decline in both bone and muscle may
indicate
greater retention as well as continued uptake of long-lived
radioactive materials in these tissues.
Figure 2 illustrates the rate of decline
in the tissues of fish from
Rongelap Island between January 25, 1955 and July 17, 1957.
Again it
will be noted that the rate of decline of radioactivity is somewhat greater
in the liver tissue than in bone or muscle.
All tissues show a definite
increase in radioactivity after the summer of 1956, reaching a relatively
higher level than for the same
tissues in fish from Kabelle Island, but
declining at a more rapid rate after 1956.
Decay and decline rates of radioactivity of muscle and bone tissue
from fish from Rongelap Island are approximately the same, decay being
slightly more rapid.
The radioactivity in liver tissue declines at a more
rapid rate than it decays.
Gross Gamma Radioactivity,
Table 3 contains
1957
data on gross
levels of gamma
radioactivity in the
homogenate of manyreef fishes collected at Rongelap and Ailinginae Atolls.
As with the beta radioactivity, Rongelap Island fish generally had less gamra
radioactivity than fish from either
Enibuk or Kabelle Islands.
Also differ-
ences were not great between similar species from different islands.
A
markedly higher amount of radioactivity was noted again in the liver of
pur’
RCH