21 
_ Introduction of radioactive materials into the oceans may also arise 
from accidents such as the sinking of the nuclear powered submarines 
USS Thresher in 1963 and USS Scorpion in 1968, or from the rupture 
of an atomic weapon as happened at Palomares, Spain in 1966. An- 
other’ source of radioactive pollution is the use and disposal of radio- 
active materials by hospitals, research facilities, and industry. After 
radioisotopes are introduced into the marine environment they may 
(1) remain in solution, (2) be absorbed on suspended particulate mat- 
ter or bottom sediments, (3) flocculate and precipitate to the bottom, 
or (4) be accumulated by plants and animals. The major consequence 
for man is the incorporation of radioisotopes into the food web and 
their progressive concentration in higher order organisms. Table XV 
lists approximate concentrations of radionuclides found in marine 
organisms. Figure 2 illustrates lethal dosages for various phyla. One 
instance of the lethal effect on marime organisms by ingestion and 
concentration of radioisotopes occurred after a nuclear detonation in 
the Marshall Islands in 1958. Investigators found that herbivorous 
fish concentrated radioactive iodine from seaweed which had previously 
accumulated this isotope from seawater. Carnivorous fish then further 
concentrated the iodine to such an extent that their thyroid glands 
were destroyed.”® 
The International Commission on Radiological Protection has 
determined the maximum permissible concentration (MPC) for con- 
tinuous exposure either by air or water to any one of 240 radioisotopes. 
If more than a single isotope is encountered, these exposure levels 
TABLE XV.—APPROXIMATE CONCENTRATION FACTORS FOR RADIOISOTOPES OF PROBABLE SIGNIFICANCE IN 
THE MARINE BIOSPHERE 
Radionuclide(s) Algae Crustacea Molluscs Fish 
80 0. 97 0.95 0.97 
4,000 3, 600 4,700 5, 400 
104 2104 6103 3.7104 
2 120 5 
1, 200 S00 es see ene 750 
2, 000 100 400 100 
3, 000 2, 000 104 200 
2104 2, 500 104 1, 500 
500 500 500 8 
103 2, 000 1.5104 1, 000 
~l1 ~l ~ ~!l 
50 2 2 
500 100 15 10 
1,500 100 5 
400 100 10 1 
rR WR MAS RR Be RI TE AE SOE ECO es TE TN oO See Es 7 194 pi tetee assaes 
ROE i SS SEE LAME See a emanate 8) caer ae 5, 000 30 50 10 
133Xe Nt ee ye a ee Ae at EN Se te aN ~!l ~l ~l ~!l 
SSAC SSO IN ES POC ee SE ES aE 15 20 10 10 
MOR astiOlQew a ei ees NY, ad be ee day Cia ae ane aS EI BY ae ve 8 
SEITEN eee eaten Cn eID OVC oe Rema tt a 700 20 400 3 
TRS eI GWie tbe CaN ROTEL DLC Pe ee ee Bye by Age 5 2 20 3 
2S ELD D Mea he maa CN TIN aN in RIN So RE a TAG A EROS cies 200 ya aro 
ZIDR ORE PU OEE DN PO INS RAS ETERS OR EAS WAN SMELT) ES oe Oh ET Bt lt el 
S2bRape Tae OES aS Te lea) 1,000 100 1, 000 130 
CEN PT) a AS a peek Seite 2 tl Pin a Woe I, 300 3 200 
Source: Rice & Wolfe, op. cit., p. 351. 
28 Gorbman, A. and M. S. James. An exploratory study of radiation damage in the thyroids of coral 
reef fishes from the Eniwetok Atoll. In Radioecology (Schultz, V. and A. W. Klement, eds.), New York. 
Reinhold, 1963: 385-399. 
