The Effects of Atomic Radiation on Oceanography and Fisheries (1957) / Chapter Skim
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COMPARISON OF SOME NATURAL RADIATIONS RECEIVED BY SELECTED ORGANISMS
COMPARISON OF SOME NATURAL RADIATIONS RECEIVED BY SELECTED ORGANISMS
Pages 28-33
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From page 28... ...
These data emphasize that doses from natural sources vary widely and depend not only upon the habitat but also upon the physical size of the organism; this natural radiation background varies particularly widely amongst aquatic organisms. A very useful summary of natural and artificial radiation to which human beings are now exposed has been published by Libby (1955)
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From page 29... ...
Geometrical factors influencing dose A man standing above a granite plane surface receives from the granite roughly one half the radiation which might strike him if he were completely surrounded by granite; likewise a man in a row boat receives from the sea only one half the dose which the sea gives to any submerged organism. Potassium yields both beta and gamma activity; roughly three fourths of the total energy comes from the beta rays.
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From page 30... ...
The effect of beta rays starting from internal sources also depends upon the size of the organism. If the organism is very small the beta bombardment from the outside sources may contribute much more than does internal activity even though the source of activity is more concentrated in the tissue than it is in the surrounding water.
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From page 31... ...
In pure fresh water the total dose from strongly ionizing rays depends largely upon the size of the organism and upon its living habits. If the organism is small in the sense already discussed, if it lives in deeper waters, if it stays away from the bottom sediments, if it avoids the neighborhood of large masses of living tissue or of detritus, and if it avoids as far as possible accumulating excessive amounts of those elements which can be radio-active -- then it can remain remarkably free from the ionizing bombardment received by all other living things.
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From page 32... ...
Near fresh water surface Cosmic rays 35 + water activity 2 + internal 2 =35 11. 100 meters deep in a fresh lake Cosmic rays < 0.5 + water activity 2 + internal 2 = < 0.5 1 For every radiopotassium disintegration there are 10 betas having average energy 0.5 mev and also one gamma ray having 1.5 mev.
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From page 33... ...
receive from their surroundings what is probably the lowest natural ionizing dose within the biospheres of the earth. It would appear that geneticists should consider seeking evidence of abnormal mutation rates amongst microorganisms which live in deep waters of clear lakes, particularly amongst those which have low affinity for radioactive elements.
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