Table If.
Isotope
The Naturally Occurring Radioisotopes in Sea Water
Total activity
Per cent
Radioactivity
in ocean in
of total
in sea water
megacuries 1)
activity
97.1
(MP C)4)
d/m/ 12)
pclcc??
uc/ce
736
3x1077
*
K40
460, 000
Rv 87
8, 400
1.77
13
6x1079
i073
238
3, 800
80
6
8x10°9
2x1074
Ra226
1, 100
23
2
1079
1077
cif
270
057
l
5x10°40
gx10-3
u235
110
023
l
"
3x1074
12
003
1
03
8
002
\
2x1075
H?
Th232
Total
473, 700
100.0
758
3x1077
1)
Revelle (1957)
2)
Disintegrations per minute per liter based upon calculated
value for K40
3)
Microcurtes per cubic centimeter
4)
Maximum permissible concentration for water congumed by man
(Handbook 69, i959)
*
No value given, hazard negligible