-33-
stems,
flowers and leaves was the same.
In these tissues
the level of radioactivity was high one week after the
Nectar test,
dropped rapidly,
100 days post Nectar,
and then leveled off at about
much like the decline of radioactivity
in the green leaves of Scaevola
in the tissues of a coconut
(Fig.
The radioactivity
(Cocos nucifera)
rapid rate for the entire period,
shown in Figure 10.
9).
declined ata
similar to the decline
The fluctuations in the plot showing
the rate of decline for the bunchgrass
(Lepturus) make a com-
parison with other plants difficult.
Soil
The gross beta radioactivity of the top two inches of
soil collected at Belle Island during the study period is
given in Table 5 and is presented graphically in Figure 9.
The beta radioactivity of the soil after the Nectar detonation decreased to the pre-Nectar level in about 150 days
at a rate which approximates the rate of decay of mixed fission products for this perioa (15) ,
The rapid decrease in
radioactivity of the soil samples was
followed by a period
of approximately one year in which the radioactivity in subsequent samples decreased at a slower rate.
These data in-
dicate that some of the radioisotopes with short half lives