Table 21. Important radioisotopes in the marine environment. The half-lives are stated in years.
The various types of radiation are marked: 0: for alpha-emitters, ~ for beta-emitters, K for K-emitters and 'Y for gamma-emitters. The concentration factors given refer to wet weight (Rice and
Wolfe 1971)
Symbol
Element
Half-life
Radiation
Concentration factor in
type
mollusc
fish
1. Natural radioactivity
3 H
Tritium a
12.3
~
14C
Carbon-14 a
5760
~
40K
Potassium40
1.3 x 10 9
~
87 Rb
Rubidium-87
4.7 x 1010
~
210 po
Polonium-210
0.38
0:
234 U
Uranium-234
2.5 x 105
0:
235 U
Uranium-235
7.1 x 10 8
0:
238 U
Uranium-238
4.5 x 10 9
0:
2. Transuranic elements
238Pu
Plutonium-238
86
0:
200
5
239Pu
Plutonium-239
24400
0:
200
5
24°Pu
Plutonium-240
6600
0:
200
5
241Pu
Plutonium-241
13,2
0:
200
5
241 Am
Americium-241
458
0:,'Y
3. Fission products in nuclear reactions
85 Kr
Krypton-85
10.6
~
1
1
89 Sr
Strontium-89
0.14
~
1
0.2
90 Sr
Strontium-90
28.0
~
1
0.2
90 y
Yttrium-90
0.007
~
15
10
91y
Yttrium-91
0.16
~
15
10
95Nb
Niobium-95
0.10
~-'Y
5
95 Zr
Zirconiurn-95
0.18
~-'Y
5
1
103 Ru
Ruthenium-103
0.11
~-'Y
10
1
106R~
Ruthenium-1 06
1.0
~-'Y
10
1
131 J
Iodine-131
0.02
~-'Y
50
10
137 Cs
Caesium-137 b
30.0
(j-'Y
10
10
144Ce
Cerium-144
0.78
~-'Y
400
3
4. Activation products
32p
Phosphorus-32
0.04
~
6000
3300
51er
Chromium-51
0.08
K-'Y
400
100
54Mn
Manganese-54
0.86
K-'Y
10000
200
55 Fe
Iron-55
2.7
K
10000
1500
S7Co
Cobalt-57
0.74
K-'Y
500
80
60 Co
Cobalt-60
5.3
~-'Y
500
80
65 Zn
Zinc-65
0.67
K -~-'Y
10000
1000
1l0A
Silver-110
0.69
~-'Y
10000
134 g
Cs
Caesium-134
2.1
~-'Y
10
10
a Is also produced from induced radioactivity
b Caesium-l37 is a /3-emitter, the 'Y-emission usually detected during classification originates from
the disintegration product barium-137
108