Atoms, Nature, and Man: Man-Made Radioactivity in the Environment

Part 1

ATOMS, NATURE, and MAN Man-made Radioactivity in the Environment

by Neal O. Hines

The Understanding the Atom Series

Nuclear energy is playing a vital role in the life of every man, woman, and child in the United States today. In the years ahead it will affect increasingly all the peoples of the earth. It is essential that all Americans gain an understanding of this vital force if they are to discharge thoughtfully their responsibilities as citizens and if they are to realize fully the myriad benefits that nuclear energy offers them.

The United States Atomic Energy Commission provides this booklet to help you achieve such understanding.

Edward J. Brunenkant, Director Division of Technical Information

UNITED STATES ATOMIC ENERGY COMMISSION

Dr. Glenn T. Seaborg, Chairman James T. Ramey Wilfrid E. Johnson Dr. Theos J. Thompson Dr. Clarence E. Larson

CONTENTS

INTRODUCTION 1 SOME PRELIMINARY IDEAS 2 A VIEW IN PERSPECTIVE, 1946-1963 8 THE ATOM IN ENVIRONMENTAL STUDIES 20 ENVIRONMENTS—SINGULAR, YET PARTS OF A WHOLE 29 PROBLEMS AND PROJECTS 41 WHERE ARE WE NOW? 52 SUGGESTED REFERENCES 55

United States Atomic Energy Commission Division of Technical Information Library of Congress Catalog Card Number: 66-61322 1966

ATOMS, NATURE, and MAN Man-made Radioactivity in the Environment

By NEAL O. HINES

INTRODUCTION

Mankind, increasingly crowding the earth, modifies the earthly environment in uncounted subtle and unpredictable ways, too rarely to the benefit of either earth or man. In this century it has become critically important that we comprehend more precisely than ever before the biological mechanisms and balances of our environment and that we learn to detect changes and to understand what they imply.

The release of atomic energy added a new dimension to the possibility of environmental change. In man’s first experiments with atomic energy, he added small but perceptible amounts of radioactivity to the earth’s natural total; as the Atomic Age matures, he inevitably will add more. But, in the course of his experiments, man has come to realize that environmental and biological studies, which now are necessary because of the use of atomic energy, may help solve not only the problems atomic energy creates but also the larger problem of how to manage wisely the world’s limited natural resources.

This booklet describes the environmental investigations that have been conducted with the aid of the atom since the first atomic detonation near Alamogordo, New Mexico, in 1945. The earth’s mysteries, however, are not easily unlocked, and investigations of our environment with atomic tools have only begun. The story thus is one of beginnings—but of beginnings that point the way, it is hoped, to a new understanding of the world in the atomic future.

SOME PRELIMINARY IDEAS

Biologists are interested in every kind of living thing. When they study organisms in relation to atomic radiations, they enter the field of radiobiology, which really is not a science in itself but merely a branch of the larger interest in biology. Biologists find that atomic energy has significance both in the study of individual organisms and in studies of organisms in their natural communities and habitats.

Radioactivity introduced into any community may be “taken up” by the biological system, becoming subject to cycling in food chains or to accumulation in plant or animal tissues. The presence of radioactivity permits study of the workings of a system as large as an ocean, perhaps, or of one no larger than a tree. And in each case it thus may be possible to observe how the cycles of organic renewal are related to the larger systems of life on earth.

The Single Environment

The environment in which we live is recognizable as a single complex, composed of many subenvironments—land, oceans, atmosphere, and the space beyond our envelope of air. The deer in the forest, the lizard in the desert burrow, and the peavine in the meadow are different kinds of organisms living in situations that are seemingly unalike. Each creature is part of its environment and a contributor to it, but it also is part of the total biosphere. All creatures are linked to each other, however remotely, in their dependence on limited environments that together form the whole of nature.

We know much about the life of the earth, but there is far more that we do not know. Understanding of the large cyclical forces has continued to elude us. We do not even yet grasp the small and seemingly random biological relations between individual organisms—relations involving predator and prey, for instance, and those among species and families—such as exist together in symbiotic harmony and interdependence. Through centuries of observation we have gained a store of information. We are left, however, with a still unsatisfied curiosity about the reach and strength of the tenuous biological cords that bind together the lives of the deer, the lizard, and the peavine.

The Need to Understand

Life on earth evolved amid constant exposure to ionizing radiation, from the earth itself and from space, known as background radiation. Therefore environmental studies must be conducted in relation to, and with understanding of, background radioactivity.

Of some 340 kinds of atoms that have been found in nature, about 70 are radioactive. Three families of radioactive isotopes—the uranium, thorium, and actinium series—produce a large proportion of the natural radiation. Other radionuclides occur singly, rather than in families, and some of them, such as potassium-40 and carbon-14, are major contributors of natural radioactivity. Traces of natural radioactivity can be found, in fact, in all substances on earth.

When man began experimenting with atomic fusion and fission, he placed in his environment—across vast landscapes, in the oceans, and in the atmosphere—measurable additional amounts of radioactivity. These additions were composed of the longer-lived members of some 200 kinds of atomic radiation. Although the additions constituted but a fraction of the background burden, they represented the first alteration of the radiological balance that had existed since the early ages of the planet. Thus it became necessary to determine what the impact of such a change might be. In the process of inquiry, these ideas emerged:

1. The addition of man-made radioactivity presents the possibility of delayed or cumulative effects. Long-term studies, geared to the assessment of biological effects from extremely low radioactivity, are essential.

Part 2

2. The addition of radioactivity makes possible broad-gauged studies to trace the movement and concentration of radionuclides in the environment. These studies, in turn, can disclose new information on biological complexes and mechanisms.

The quantities of low-level long-lived radioactivity already released into our environment will provide materials for future studies covering decades. Further, because radioisotopes are chemically similar to nonradioactive forms, observation of their biological fate will provide clues to the transport, concentration, dilution, or elimination of many other kinds of man-made toxic agents and contaminants of the environment.

Operating Concepts

Environmental problems are best approached in the environment itself, where all the natural variables and unknowns are present. Laboratory work is essential, but no laboratory can carve from nature or reproduce artificially all the complexities of the natural environmental “laboratory”, the ecosystem.

Environmental studies frequently demand the coordinated attentions of ecologists, chemists, physicists, geologists, oceanographers, meteorologists, botanists, zoologists, and others, all working together to approach the environment as a synchronized mechanism.

Finally, environmental studies are conducted with a special consciousness of the need to withhold judgment as to what is meant by “effect”, particularly “radiation effect”. Gross, immediate effects may be determinable. Ultimate effects may be generations in the making, remote in time and space from their causes. Studies thus are focused on biological processes and on isolation and identification of the long-range trends.

A VIEW IN PERSPECTIVE, 1946-1963

Bikini Atoll, in the Marshall Islands, represents, in miniature, a world that has experienced all the forces, immediate and residual, that can result from nuclear detonation.

Bikini in 1946 was the scene of the first peacetime tests of atomic weapons. One of these tests involved the detonation of an atomic device under water, in the heart of the atoll’s aquatic circulatory system. Bikini also was used for 5 years, from 1954 through 1958, for the testing of thermonuclear devices. Its islands and reefs were burned by atomic heat, and the waters of its lagoon were contaminated by deposits of radioactive fallout. Thus, for almost a score of years, Bikini, a small outcropping of coral in the mid-Pacific, was identified with the earliest experiments in nuclear explosion.

Through the years of testing and later, Bikini also was the site of repeated biological investigations. Teams of scientists examined Bikini annually from 1946 to 1950 and from 1954 to 1958. Then in 1964, after an interlude of 6 years in which Bikini was undisturbed either by weapons tests or human visitors, scientists went there again to make a comprehensive ecological resurvey.

The scientists found in the Bikini ecosystem, in low but perceptible amounts, residual traces of radioactivity deposited by the tests. On certain islands, craters dug by nuclear explosions still gaped in the reefs. The test islands still bore nuclear scars, and in some areas of the lagoon corals and algae had been killed by silt stirred up by the detonations. But Bikini’s life system clearly was in a process of healing. Large islands were covered by regrowths of vegetation; on some, the masses of morning glory, beach magnolia and pandanus were growing so densely that field parties had extreme difficulty cutting paths through them. Bikini Atoll, scientists believed, needed only clearing and cultivation to make it once again suitable for human habitation.

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