Table III.
Radioisotopes Present in Plankton Collected soon
after Fallout
Isotope
Half life
Per cent of
total radioactivity
Bomb debris
Np239
2.3 days
69
y237
6.8 days
3
Fission products
Mo99-T¢99m
66 hours
12
Te 132-1132
77 hours
8
Rul93-Rp103
40 days
Rul05_pp,105
36 hours?)
Ru106_Rp106
3
il year
Bal40-7,a140
12.8 days
2
Cel4i1_p,141
33 days
2
Zr95-Np95
65 days
1
285 days
<1
Cel44_p,144
100+
1) Data from Lowman (1960); average value for six samples
collected less than 48 hours post shot; fallout from one
detonation; Rehoboth survey (1958)
2) Half life of daughter