Table Il. The Naturally Occurring Radioisotopes in Sea Water
Isotope
K40
Total activity
Per cent
megacuries 1)
activity
in ocean in
460, 000
of total
97.1
Radioactivity
in sea water
(MP C)y*)
d/m/12)
pefec?)
pefcc
736
3x1077
*
Rb8?
8, 400
1.77
13
6x10-9
10-3
y238
3, 800
80
6
3x10°9
2x1074
Ra226
1, 100
.23
2
10-9
10-7
cl4
270
057
1
5x10-10
gx10-3
y235
110
023
1
"
3x1074
12
003
1
"
03
8
002
1
"
2x1075
H3
Tn232
Total
473, 700
100.0
758
1) Revelle (1957)
2) Disintegrations per minute per liter based upon
calculated value for K49
3) Microcuries per cubic centimeter
4) Maximum permissible concentration for water
*
consumed by man (Handbook 69, 1959)
No value given; hazard negligible
3x1077