Table II. The Naturally Occurring Radioisotopes in Sea Water
Isotope
K40
Total activity
Per cent
Radioactivity
in ocean in
of total
in sea water
460, 000
97.1
megacuries 1)
activity
(MP C)y*)
d/m/12)
yefcc3)
—ye/ec
736
3x10-7
*
Rb8?
8, 400
1.77
13
6x1079
10-3
y238
3, 800
. 80
6
3x10-9
2x1074
Ra226
1, 100
23
2
1079
1077
ci4
270
057
1
5x10710
gx10-3
y235
110
023
1
"
3x1074
12
003
l
"
03
Th232
8
002
1
"
2x1075
Total
473, 700
H3
100.0
758
1) Revelle (1957)
2) Disintegrations per minute per liter based upon
calculated value for K40
3) Microcuries per cubic centimeter
4) Maximum permissible concentration for water
*
consumed by man (Handbook 69, 1959)
No value given; hazard negligible
3x1077