Crustacea 
en 
3 ary — 
= 
ay 
: 10% 103 10° 
Roentgens 
Figure 2.—Lethal doses of radiation for different phylogenetic groups. Senistivity~ 
to radiation generally increases with increasing complexity of organisms. 
Source: Donaldson, L. R., Evaluation of radioactivity in the marine environment of the Pacific Proving” 
Sipund: In “Nuclear detonations and marine radicactivity,’’ (Small, S. H., ed.), Norway. Kjeller, 1963: 
must be reduced accordingly. The MPC for any completely unknown 
mixture of radionuclides is set at 1077 uCi/em* for continuous exposure. 
With regard to the marine environment, the danger of radiation expo-. 
sure to man would arise from eating contaminated seafood. Marine 
organisms concentrate some elements to high degree. Evaluation of 
marine contamination by radioactivity is complicated by diverse 
environmental and biological variables that affect the disposition of a 
radionuclide introduced into the oceans. Varying patterns of con- 
sumption of any given seafood species also affect the MPC. 
Man’s major contact with the oceans has been and probably will 
continue to be the coastal areas. The coastal areas are most likely to 
receive radioactive effluents from river systems. Much of the radio-- 
activity will become incorporated into sediments of estuaries where 
many marine organisms live or reproduce. About 66 percent of the. 
total catch of commercial marine species comes from the coastal zone, 
from waters less than 25 fathoms deep. Consequently, the estuaries. 
and bays are where the impact of man’s nuclear technology is most- 
likely to be felt. 
