Proving Ground (Chapter Three)

Explore Collection

The following text is excerpted by the permission from the University of Washington Press from the book Proving ground; an account of the radiobiological studies in the Pacific, 1946-1961, by Neal O. Hines, Seattle, Wash.: University of Washington Press, 1962.


The Possible Usefulness of a re-examination of Bikini Atoll at some point in the future occurred to members of the staffs of Joint Task Force One before Operation Crossroads was concluded. From the standpoint of the Navy, much obviously yet was to be learned, and in the broader fields of scientific investigation the momentum of inquiry was far from exhausted in a single summer. The fact that the atoll had been measured, sounded, and catalogued so thoroughly before Crossroads made almost irresistible a further, similar study after the tests. In the introduction to the subsequent technical reports it was recalled that at the time of Crossroads certain questions necessarily had to remain unanswered, either because post-test radiation made desired inspections hazardous, or because the questions were concerned with long-range effects. For example, the problems of how long and in what ways abnormal radioactivity affects the flora and fauna of a region could not be solved immediately.

The preliminary statement of the Crossroads Evaluation Board, filed shortly after the close of the 1946 tests, noted that:

Although lethal results might have been more or less equivalent, the radiological phenomena accompanying the two bursts were markedly different. In the case of the airburst bomb, it seems certain that unprotected personnel within one mile would have suffered high casualties by intense neutron and gamma radiation as well as by blast and heat. Those surviving immediate effects would not have been menaced by radioactivity persisting after the burst.

In the case of the underwater explosion, the airburst wave was far less intense and there was no heat wave of significance. Moreover, because of the absorption of neutrons and gamma rays by water, the lethal quality of the first flash of radiation was not of high order. But the second bomb threw large masses of highly radioactive water onto the decks and into the hulls of vessels. These contaminated ships became radioactive stoves, and would have burned all living things aboard them with invisible and painless but deadly radiation.

It is too soon to attempt an analysis of all of the implications of the Bikini tests. But it is not too soon to point to the necessity for immediate and intensive research into several unique problems posed by the atomic bomb. The poisoning of large volumes of water presents such a problem.

Joint Task Force One went out of existence on November 1, 1946. It was succeeded on that date by a Joint Crossroads Committee of five members and thirteen supporting officials. The chairman was Rear Admiral Parsons, who had served as Deputy Task Force Commander for Technical Direction. Members of this committee, already familiar with the character of the Crossroads problem, pursued the question of a resurvey of Bikini Atoll. They believed that the radiation problem should be assessed after some time had passed and after residual contamination had had opportunity to decay or to produce observable effects. Other factors also suggested the desirability of a return to Bikini. The Navy desired to obtain detailed observations and photographs of the ships sunk in Test Baker, including the Saratoga and the Nagato and the submarines Pilotfish and Apogon lying at the bottom of Bikini lagoon; to recover ionization, pressure, and damage gauges from the Nagato; to search for any existing fragment of LSM 60, the landing craft beneath which the Baker bomb had been suspended; and to attempt to make a comprehensive estimate of Bikini's physical condition after the atomic tests. Plans also were made to send drills into the Bikini Island reef to make a new study of the depth of the coral above the atoll's rocky base, a project that Darwin would have applauded. Oil-rig crews were to accompany the expedition for this purpose.

Members of the Joint Crossroads Committee made preliminary inquiries into the feasibility of a survey and eventually appointed a subcommittee under the chairmanship of Rear Admiral T. A. Solberg, Navy member, and including Roger Revelle, then a Commander in the Navy and head of the Geophysics Branch of the Office of Naval Research, and Commander E. S. Gilfillan, Jr., technical director of the committee. A proposal went at length from the committee to the Joint Chiefs of Staff and on May 16, 1947, the Joint Chiefs, in a memorandum signed by Fleet Admiral W. D. Leahy, U.S.N., asked the Navy Department, in cooperation with the War Department, to conduct a Bikini Scientific Resurvey in the summer of 1947. A target date of July 15 was set for the start of operations at Bikini. The plans were being developed, necessarily, without specific reference to the existence of the new U.S. Atomic Energy Commission, which was in its first and formative months after taking over the facilities and the residual functions of the Manhattan District at the first of the year. The Joint Chiefs of Staff memorandum asked, however, that technical direction of the resurvey be assigned to the Joint Crossroads Committee or its successor organization, the Armed Forces Special Weapons Project, created with the Commission to represent the continuing interests of the three armed services in atomic developments. Revelle served as project officer of the resurvey until he was succeeded by Commander C. L. Engleman on June 13. Commander Gilfillan, who had participated in Crossroads as a member of the technical staff and as executive officer of the Nagato, was made Technical Director of the new operation. The Task Group commander was Captain T. A. Hederman U.S.N.

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The Bikini Scientific Resurvey was conceived as a concluding phase of Operation Crossroads and it was organized as a full-scale effort to follow up, a year after the tests, the geological, biological, and oceanographic investigations that had been started months before Crossroads and continued throughout the testing period. Donaldson and other members of the Applied Fisheries Laboratory staff, who already had expressed interest in further examinations of Bikini materials, were invited to participate as members of the Radiobiology Group. By 1947, the Laboratory program had been shifted to sponsorship by the Atomic Energy Commission, and F. H. Rodenbaugh, Sr., consultant to the Medical-Legal Board of the Commission, was a member of the radiobiology staff for the resurvey. Donaldson remained a Commission consultant in connection with the Hanford work.

The resurvey, placed under the operational control of the Commander in Chief, Pacific Fleet, employed as its flagship the U.S.S. Chilton (APA 38), which was to be supported by the Coucal (ASR 8), the LSM 382 and, later, by the LCI (L 615). Additional small craft were taken along for lagoon and landing operations. The scientific and technical staff included about eighty persons, most of them grouped as members of teams concerned with geology, biology, fisheries, radiobiology, radiochemistry-radiophysics, radiological safety, radiological health, engineering, and aerology. Total personnel taken to Bikini numbered some 700, including officers and crews of the resurvey vessels, service staff officers and representatives, and members of special project groups.

Scientists participating in the new Bikini operation were representative of the disciplines in which interest now was focused. Those who would continue the examinations of island and reef geology included the U.S. Department of the Interior geologists, H. S. Ladd and J. I. Tracey, who had taken part in the comprehensive pre-Crossroads studies of Bikini, and associated with them were J. Harlan Johnson, of the Colorado School of Mines; J. W. Wells, of the Ohio State University; and G. G. Lill, of the Geo-physics Branch of the Office of Naval Research.

In the fisheries group were R. W. Hiatt and V E. Brock, of the U.S. Fish and Wildlife Service, reef and lagoon fishes; O. R. Smith and J. C. Marr, aquatic biologists of the Fish and Wildlife Service, and G. S. Myers, professor of biology and curator of the Zoological Collection, Stanford University, pelagic fishes; and L. P. Schultz, curator of fishes of the U.S. National Museum, population and taxonomic studies.

Experimental biologists included three representatives of Stanford University, D. M. Whitaker, of the Department of Biology, L. R. Blinks, director of the Hopkins Marine Station, and G. M. Smith, professor of botany; P. M. Brooks, associate plant physiologist of the Stanford Research Institute; and W. A. Gortner, associate scientist, and T. F. Goreau, assistant oceanographer, Scripps Institution of Oceanography. Ecological and morphological studies were conducted by J. P. E. Morrison, associate curator of mollusks, and F. M. Bayer, assistant curator of marine invertebrates, U.S. National Museum; and A. C. Cole, professor of zoology and entomology of the University of Tennessee.

With the radiochemistry and radiophysics group were W. H. Hammill, associate professor of chemistry, and R. R. Williams, assistant professor of chemistry, of the University of Notre Dame, who were interested in fission products chemistry; Jack Schubert, assistant professor of physiological chemistry. University of Minnesota, plutonium chemistry; L. F. Seatz, assistant professor of agronomy. University of Tennessee, soils chemistry; and J. H. Roberson, physicist, Clinton Laboratories, Oak Ridge, radiophysics.

Revelle, who had been the resurvey's first project officer, was to join the resurvey at Bikini on July 15.

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The radiobiology group was headed by Donaldson and included Welander, Pautzke, Rodenbaugh, and seven associates and assistant scientists drawn from the University of Washington and the Applied Fisheries Laboratory. Among these was Foster, supervisor of the laboratory at Hantord, Allyn H. Seymour, then a biostatician with the International Pacific Halibut Fisheries Commission; and R. C. Meigs, assistant chief biologist of the Washington Department of Game.

The Chilton, berthed at the San Diego Naval Station pending her departure for the Marshalls by way of Pearl Harbor, was provided with survey facilities which included two radiochemistry laboratories, a radiation counter room, a laboratory for the use of Donaldson's radiobiology group, a fisheries laboratory under the direction of Brock, and an experimental biology laboratory which, when moved ashore at Bikini Island, became two laboratories-one devoted to morphological and physiological studies of plants and the other to studies of marine invertebrates. In addition to these, three scientific group centers subsequently were established on Bikini Island to facilitate studies of low-level radiation, of geology and aerology, and of the relationship of marine organisms to the chemical content of sea water.

The character of the preparations reflected the general interest in the levels of residual radioactivity that might be found at Bikini. The question of radioactivity was, in fact, uppermost in the minds of the scientists and members of the Navy staffs even though the Bikini Scientific Resurvey program also was set up to satisfy, so far as possible, curiosity about both the general scientific questions and the more specific matters such as types of structural damage sustained by the sunken target ships. In Admiral Leahy's original memorandum to the Secretary of the Navy on May 16 the purposes of the resurvey had been stated thus:

The resurvey would entail the collection of biological specimens, diving on target ships to recover specific instruments and to make certain structural examinations, the taking of water and bottom samples and cores, and radiological studies of the lagoon, the surrounding islands and organisms with particular reference to analysis of hazards from alpha radiation and from possibly contaminated food organisms.

The concern about alpha radiation, undoubtedly reflecting concern expressed in discussions of members of the Joint Crossroads Committee, revealed the presence of the thought that the field surveys necessarily performed hastily after Test Baker, and under conditions which permitted only gross measurements of beta and gamma radiation, had been inadequate to disclose the potential ingestion by Bikini's biological system of the low-penetration alpha emitters. Such concern with radiation formed a large element in the planning, for the character of the work at Bikini would be governed by what was found at the atoll when the Chilton and her little fleet moved through Enyu Passage into the lagoon on July 15.

Operation Crossroads had been conducted in a spotlight of world attention. The Bikini Scientific Resurvey claimed no such general interest. The resurvey, on a scale infinitely smaller than that of Crossroads, was a mixture of military and scientific interests and objectives translated into action under security conditions which made it necessary to filter information through official channels. The conditions were inevitable and they would continue to exist throughout the subsequent Pacific test operations, but they reduced almost to zero the possibility that the public or, for that matter, the scientific community, would have access to information making the qualitative distinctions that would be necessary thereafter in reports of radiation effect. As for the immediate public information question, the Navy task group included a public information officer whose small staff operated under a carefully prepared plan, but matters relating to atomic programs bore security classifications and the responsibility for clearance and release rested with the Navy Department's Director of Public Information in Washington, D.C. In addition, the very nature of the project made impossible the release of any information having conclusive meaning.

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For all this, there was an atmosphere of inquiry about the proceedings that was altogether genuine. The resurvey was, after all, returning to an atoll which had last been seen in the rush of evacuation after Test Baker and which not only held scientific problems of interest but which had the appeal of association with events of epoch-making dimensions.

The Chilton departed San Diego on July 1, 1947, and from then until her arrival by Bikini on July 15 members of the scientific groups were organizing their laboratories and working, formally or informally, to plan their operations. On July 2 the project officer, Commander Engleman, appointed an advisory board under the chairmanship of Whitaker and including Donaldson, Ladd, Roberson, Schultz, and Richard D. Russell, of the Navy Electronics Laboratory (E. H. Shuler and Tracey were to act for Russell and Ladd until their arrival at Bikini) to provide counsel on such administrative matters as use of space and equipment, and at a meeting of the board on the same date Whitaker and Donaldson were named cochairmen of a seminar series designed to inform all members of the scientific groups of the purpose and methods of the Bikini studies. Engleman opened the series by reviewing films of Operation Crossroads, and subsequently, as the Chilton cruised to Pearl Harbor and then westward toward the Marshalls, seminar lecturers included Wells on Pacific geology, Tracey on the geology of Bikini, Morrison on the invertebrates, Schultz on fishes of the Pacific, Brock on reef collecting, Welander and Rodenbaugh on the effects of radiation. Commander H. S. Etter and Lieutenant Colonel C. E. Grant on operation plans for radiological safety, and—when the Chilton reached Bikini—Revelle on the phenomena of the Baker explosion.

The Chilton, accompanied by the Coucal, entered Bikini lagoon at 10:30 A.M. on July 15. To starboard lay the curved reef leading from Enyu Passage to Bikini Island, the Chilton's objective. The Coucal, from which were to be conducted the diving operations for further examination of the target ships, was stationed in the former target area near the position of the sunken Saratoga. When the Chilton had dropped anchor off Bikini Island, Engleman led ashore the landing party that was to make preliminary reconnaissance, the group including Donaldson, Rodenbaugh, and L. B. Marquiss, of the radiobiological team. All members of the initial group were required to wear long-sleeved shirts, full-length trousers, and heavy boots. All also wore film badges. Counters and film badges carried inland showed no beta or gamma radiation substantially above normal background, and the only significant counts of activity were found at the scraps of Crossroads gear—old life rafts, planks, fenders, and such—which littered the lagoon beach and which probably had been washed ashore from the target vessels. Samples of miscellaneous materials were collected from scattered parts of the island and returned to the Chilton to be counted for possible alpha contamination. Members of the landing party were monitored on their return to the Chilton to preclude any possible contamination of the ship, and a change station was set up for handling work clothing and gear. After the initial landing on Bikini Island, Commander Gilfillan took another group to Eninman (Prayer) Island, on the south rim of the atoll and adjacent to Enirik (Erik) Pass, for further monitoring of the reef and beach at a point of outflow of waters from the lagoon. Surface counts of radioactivity there were at the same levels as those encountered on Bikini. By the following day, July 16, the offloading at Bikini Island was under way and members of the scientific groups were readying their shore stations and laboratories and beginning their collections and samplings.

It would be hazardous, years after the event, to attempt to suggest, much less to evaluate, the interests that must have hovered about the activities of the Bikini Scientific Resurvey. It would be difficult to endeavor to recreate the atmosphere of carefully regulated anticipation in which the resurvey groups approached their tasks. Diverse moods, purposes, and scientific and military points of view were fused, it may be imagined, by a common feeling that this small postscript to Operation Crossroads might contain the substance of the matter—that whatever radioactive residues of Test Baker now existed would reveal, in their amounts and distributions, circumstances more deeply significant than had yet been realized, or that the absence of meaningful quantities of radioactivity would constitute a showing, on the other hand, that a problem had ceased to exist. It certainly would have been impossible to participate in the return to Bikini without sharing a sensation of excited recollection, for Bikini was so well known that even those who were visiting the atoll for the first time could experience a sense of recognition. Bikini was empty and silent, but out where the Coucal was anchored, a mile-high column of water had erupted in the lagoon, less than a year before, in a moment so awesome that many members of the Crossroads crews, watching on vessels a dozen miles away, had become violently ill. The ghost of that column still inhabited Bikini—the column certainly would stand there forever in the picture records of the atomic age—but if the ghost were to be laid it was necessary to get at the truth about the unseen forces of which it was the manifestation. The Bikini Scientific Resurvey went to the Pacific to face the ghost, perhaps to lay it. But first it had to be hunted out.

The consciousness of the resurvey's association with Operation Crossroads was reflected, quite naturally, in press releases transmitted by the Navy through Washington, D.C. On July 15, the day of the landing, the press section noted:

The Navy reoccupied Bikini Island today, just 355 days after the underwater atomic bomb blast sent a mile high column of radioactive sea water crashing down on the Operation CROSSROADS target fleet.

Geiger counters indicated some radioactivity on the beach. However, CDR. E. S. Gilfillan, Jr., U.S.N.R., technical Director for the project, said the amount recorded was not dangerous. Stronger amounts of radioactivity were noted on life rafts and other gear cast up on the beach. It is believed some of this material may have been blasted loose from ships of the target fleet last year. . . .

Later, on July 17:

Below the surface of Bikini lagoon Navy divers today walked up and down the flight deck of the gallant old aircraft carrier SARATOGA.

They reported that the 33,000 ton ship, sunk last July 25 by an underwater atomic bomb explosion, is resting on nearly even keel. The top of her mast can be seen a few feet beneath the surface of the lagoon.

Waterproof Geiger counters were lowered in the water ahead of the divers while radiological safety monitors topside kept a careful watch on the meters. As an additional safety precaution, each diver carried three photographic film badges and a gauge that tabulates cumulatively the amounts of radioactivity to which it has been exposed. . . .

There would not be, either during the course of the survey or at the end, when the results were being compiled, disagreement as to fact. The levels of residual radioactivity were low and, as Commander Gilfillan said, they were not dangerous. The Navy originally had forbidden task group personnel to eat coconuts or other fruit growing on Bikini Island or fish caught in the lagoon. Even samples of fish, vegetation, or other materials could be taken aboard the vessels only by scientific personnel and then only with attention to proper care and packaging. By July 24 the ban against eating coconuts had been lifted, although fish still were proscribed, and this on the advice of a three-man medical-legal board which included Rodenbaugh. The concern about the immediate hazards of radiation was beginning to subside. Scientists and technicians patrolling the islands and beaches, navy divers probing about and photographing the sunken target ships, and drillers sinking shafts into Bikini coral were working long hours on a six-day-a-week schedule, but on July 25 the Navy information office reported:

Sun-tanned sailors and scientists observed the anniversary of the world's first underwater atomic bomb explosion today by going swimming in the clear blue-green 84° warm waters of Bikini lagoon. They swam from beaches that one year ago were lashed by high and angry waves thrown outward from the explosion point.

One year later the scientists and military personnel now engaged in an intensive six week resurvey of Bikini Atoll can find few visible effects of that blast. Except for activities of the 700 man Bikini Scientific Resurvey Task Group, Bikini is the same placid palm ringed lagoon on which King Judah and his subjects sailed in outrigger canoes.

Fish and other forms of marine life still inhabit Bikini's teeming tropical waters. On the islands, coconut palms, pandanus, papayas, and other forms of vegetation threaten to obscure man-made installations left from last summer.

Only the scientists and military technicians now engaged in a painstaking examination of the atoll can complete this picture of Bikini one year after Baker Day, and 37 days of hard hot field work and laboratory analysis lie ahead of them before they will have obtained sufficient data to piece together the study of long range effects of last summer's two atomic explosions.

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The field work of the Radiobiology Group was performed at some fifty-five collection stations on the rim of the atoll and in the waters between Bikini Island and the target area. The stations were selected for the probable relevance of the samples to be obtained in each. The studies in radiobiology were designed to assess the incidence of radioactive materials in organisms taken from various geographic locations, to determine the quantities of radioactive substances in certain tissues and organs, and to gather materials for later histological studies relating to possible presence of anomalies or radiation-induced genetic effects. The selection of the sampling stations necessarily was made, therefore, with appropriate consideration of all the factors which might bear upon the results. Collections were made in the target area and in the vicinity of Bikini Island and along the northeast reef between Bikini and Aomoen Islands, over which the wind of 1946 had carried the fallout from Test Able. Attention was given to Enyu Passage, where the inflow of waters to the lagoon was accelerated seasonally by the arrival of swells originating in the southern ocean. Collections also were made at Namu Island, far to the northwest of the atoll, and along the southwest and southerly curve where deep passes—Bokororyuru (Boro), Bokoaetokutoku (Boku), Ourukaen (Oruk), Arriikan (Aran), Rukoji (Ruji), and Enirik (Erik)—permit the escape of lagoonal waters cycling and circulating under the steady pressure of the surface winds.

The problem was to obtain, even in six weeks of unremitting effort, collections of biological specimens sufficiently large and diverse to be meaningful, and to obtain such collections at fifty-five stations spotted about an atoll of 243 square miles. Samplings of similar kinds were being made by the groups studying reef and lagoon fishes, the pelagic or ranging fishes, the marine invertebrates, the reef and lagoon algae, and classifications of atoll life Collections were made independently at independently established stations, although there was a considerable amount of cross checking of data and exchange of specimens.

The collections were made, as in 1946, by hand or by the use of small gear. Nets were employed to gather plankton, and occasion ally improvised dredges for bottom specimens. The larger species of fish were taken by hook and line, but for the smaller varieties some less haphazard method of capture was required. The result was that most of the collecting, and the collecting that proved the most fruitful, was accomplished by day after day of swimming and diving about the reefs and lagoonal coral heads and walking along the miles of sandy beaches to examine the life in the shallow waters and the tide pools. The Navy report described the activity:

On the average working day, a geological party would be out studying one of the reef structures and taking samples which were duly returned to the Laboratory on Bikini Island for further study. Meanwhile, drilling operations designed to furnish additional geological information would be proceeding on Bikini Island . . . , and the Submarine Geologists would be taking cores and samples from the bottom of Bikini Lagoon.

On the same day, two or three groups of scientists, including members of the Radiobiology and Fisheries Groups, would be at different locations along the reefs of Bikini Atoll, either collecting sample specimens for purposes of determining the existing degree of radioactivity, or conducting studies concerned with the habitats, food chains, and taxonomic relationships. Many of the localities where such studies were carried on proved to be relatively inaccessible because of the coral growths beneath the surface; in such cases rubber boats and wherries proved to he invaluable items of equipment.

On August 6, Juda, the Bikini magistrate, and three of his alaps were brought to Bikini from Rongerik by courier plane to spend several days visiting islands of the atoll to determine if they could note changes in their home environment. The visitors, with the help of an interpreter sent from Kwajalein, contributed to the scientific record the Marshallese names of certain plants and fish, but the only change they professed to notice was the presence of a new plant, papaya, the seeds of which may have been introduced during Crossroads. Juda and his associates were returned to Rongerik on August 11.

The Radiobiology Group's collections of 1947 were made against the relatively thin background of information assembled in the midst of the atomic test operations of the year before. Some of the 2,000 samples harvested in the Crossroads period had been taken before Test Able, when Bikini was tree of contamination, but the others had been gathered between Tests Able and Baker or, in haste, while high-level Baker radioactivity still moved about in the waters of the target area. In 1946, some of the sampling had been done at Rongelap Atoll, to the east, and at Kwajalein, to the southeast, so that after the Bikini shots the counts of Bikini radioactivity could be compared to those of specimens from radiologically uncontaminated atolls. In 1947, to continue the studies of comparative values, sampling was accomplished again at Kwajalein and at Rongerik, Rongelap's eastward neighbor. Samples of algae and other marine organisms also were taken by divers from the sunken target ships which had rested for a year on the floor of
Bikini lagoon.

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The determination of the gross levels of radioactivity in samples of tissue was made by reducing to ash, on a steel plate placed in a muffle furnace, a tissue sample of convenient size, usually one gram, and then obtaining a count of radiation in one of the argon-alcohol Geiger tubes in the Chilton's laboratory.1 The reduction to ash eliminated tissue bulk and left on the plate only the tissue residue and any radioactive materials which might have been present therein. In the process of counting, corrections were made for the presence of normal background radioactivity, for the effect of the geometry of the radiation emission, and for the absorption of emissions by even the small sample residue. It was necessary for the counting of samples to be in sufficient number to establish a general pattern, if any existed, of the presence of radioactivity in the various organs of the fish—the skin, bone, gut, spleen, liver, or other—or in the organs or components of the other marine specimens, animal or vegetable, taken from Bikini waters.

In all, 5,883 specimens were assembled by the Radiobiology Group, including those contributed by other teams. Of these, 735 specimens were processed in the field (2,562 samples were counted) and the others preserved for later analysis. Principal attention was given to gross beta-gamma radioactivity counts, although some counts for alpha radiation also were made. The data indicated an exceedingly wide distribution of radioactive substances in organisms collected in and about Bikini Lagoon.

The collection of fish at Kwajalein was near the stern of the dead hulk of the former German cruiser, the Prinz Eugen, a target vessel that had capsized on a coral shelf at Kwajalein Island after being towed from Bikini the year before. The thirteen fish gathered there were ashed and counted whole, but radioactive materials were present only in trace amounts. Samples of liver obtained from thirty-five fish caught at Rongerik by the Fisheries Group also were subjected to radioanalysis. The liver of an ocean skipjack and liver samples from several tuna yielded counts of radioactivity substantially above normal levels, and it could only be guessed that these particular ocean rangers had obtained active substances by feeding at Bikini before they were captured at Rongerik.

The derris root method was not suitable for capture of the larger fishes. For these trolling gear operated from 45-foot picket boats was used. To obtain its samples for studies of the pelagic fishes, the Fisheries Group employed three such picket boats, each under the direction of a commercial fisherman. Some forty-eight boat days were fished at Bikini and twenty-three at Rongerik. In these operations, 506 fish were caught near Bikini and 185 in the Rongerik area. These specimens were identified, catalogued as to sex and degree of maturity, and examined for stomach content and the presence of gross abnormalities. (Stomach content data was sought from all animal specimens as a means of determining more precisely the place of the organism in the Pacific food chains.) Routine data also included notes on the length and weight of the specimens and on color patterns, ecology, and behavior.

Work proceeded simultaneously on a dozen fronts. Hiatt was studying reef and lagoon fishes to determine the food chains represented on Bikini reefs. Marr and his associates not only were seeking the pelagic fishes but were collecting small or larval fishes of pelagic types that could be caught in young-fish trawls towed at various depths. Schultz was concentrating on taxonomic studies of the fish population. Whitaker was working with invertebrates, particularly the great slate pencil sea urchin (Heterocentrotus trigonarius), which was found flourishing on that section of the Bikini Island reef over which radioactive waters had flooded after Test Baker. Myers, in a program complementing Whitaker's, was endeavoring to discover if there were ascertainable effects within the vertebrate population, which included the lizards. Cole studied insect populations, finding posttest comparative data impossible to assemble because no similar studies had been made prior to Crossroads and before the atoll had been sprayed by DDT as a health and safety measure. Examinations of land snails, reptiles, birds, and mammals were directed by Morrison, who had made the survey of Bikini's land animals before the 1946 tests.

In such a survey, in which teams of specialists attacked in a compressed period of time specific elements of a total problem, a final answer could by no means be expected to come clear at once. Even though the sampling necessarily was far from complete (and frequently, as in the trolling for the larger pelagic fishes, frankly miscellaneous), the very numbers and varieties of specimens made the task of observation, dissection, data-recording, radioanalysis, and reporting an enormous one. The Chilton's laboratories and the shore equipment and installations, fixed or portable, were in use for long and tedious hours by sweating men who returned from the field, loaded with gear and sample bags, to attempt to add bits of information to the records for which they were responsible. In such a survey, only the immediate and obvious really could be grasped, and almost every group was forced to put off until some later time the final statement of conclusions that were significant. But in the immediate view was the conclusion that, a year after Crossroads, no deleterious effects attributable to radioactivity, no biological abberations or departures from the known norm, were observable. There were qualifications. There were frequent doubts. There were suggestions that additional evidence was needed. Occasionally, there were reports of situations in which radioactivity might, indeed, have played a part—unless, as was possible, some other factor was present and, in the year since Crossroads, had produced the observed result. There was no doubt that decay and dilution had reduced residual radioactivity to a low level, but certain questions persisted, nevertheless.

For example, there was the question of an unexplainable turbidity of Bikini lagoon's eastern waters, the waters about the target area and near Bikini Island. In 1946, before Test Baker, the waters had been clear and transparent, so that the bottom could be seen at depths of more than one hundred feet. In 1947, even as the Chilton moved through Enyu Passage on the return to Bikini, it was noted immediately that the lagoonal waters were opaque and obscure, so much so that objects were visible in the water at little more than thirty feet. There was an initial suspicion that the increase in opacity indicated a significant change in the biological condition of the atoll, but what change was likely to produce such a result no one was prepared to say. Whatever the condition, the scientists thought, plankton would be participating.

Plankton studies had not been projected in the original planning for the Resurvey. Late in July, however, after the groups had been at work about ten days, it was decided, at a meeting including Revelle, Gilfillan, Brock, Marr, Schultz, and Myers, that the difference in appearance in Bikini waters (as compared to the appearance in 1946, when pre-Crossroads sampling had been performed by Martin Johnson, of the Scripps Institution of Oceanography) made perfectly logical some effort to obtain quantitative data on plankton, not only to see what quantitative changes had occurred since 1946 but to permit comparisons with the situation at Rongerik, where the waters were clear and sparkling. Accordingly, seventeen surface tow-net hauls (two to tour feet in depth) were made in various sectors of Bikini and Rongerik lagoons between July 29 and August 14. Because the plankton work had not been anticipated, equipment was inadequate or improvised and thus the results were not exact. Nevertheless, "reasonable" conclusions could be enumerated. In plankton content, the upper waters of Bikini at the target area and of Rongerik, at a comparable distance from the main island and reefs, appeared about the same. Amounts of plankton in the shallow waters (a quarter of a mile or more off the beach of the main island) were greater at Bikini than at Rongerik, where the water was much clearer. Amounts of plankton diminished as hauls were made west and south from Bikini Island and away from the target area. Inexplicably, apparently, representatives of one variety of plankton, the ctenophores—jellylike animals, two to four inches long—were found in numbers in the vicinity of the Chilton throughout the period of the Resurvey, yet only rare specimens were observed or captured in other parts of Bikini lagoon or at Rongerik. In short, plankton were flourishing most prolifically, and in one instance almost uniquely, in the waters between Bikini Island and the target area.

None of the plankton work was related in any specific way to the radioactivity question. Qualitative evaluations were not attempted at Bikini. In 1947, it was suggested that the turbidity of the Bikini water was the result of some seasonal effect (a suggestion that subsequently was rejected) or that the increase in plankton near Bikini Island was the result of the deposits of nitrogenous waste products by personnel of Operation Crossroads in 1946. It was agreed that the Bikini turbidity was unique, but no one could assert that the two atomic explosions, whether by blast effect or radiation, had set up a condition that would encourage an increase in plankton.

Below the waters of the target area, however, was a condition which was more familiar to the Navy divers who continued to explore and photograph the sunken target ships but which also was of great importance to members of the scientific task groups. This was the condition of the bottom of the lagoon about the point at which the LSM 60 had been disintegrated by the detonation of the atomic device suspended beneath her hull and where there now was a vast area of radioactive mud.

Ladd and Tracey and their associates continued in 1947 the studies of island, reef, and ocean geology undertaken in connection with Crossroads. These included studies of the seaward reefs outside Bikini Island and of the geological zonations outside and inside Bikini lagoon. Traverses made by dredge or other methods in 1946 were re-examined during the Resurvey and in the course of these particular attention was given to that part of the lagoon bottom that had been disturbed by the Baker test. One of the major objectives was to investigate, by taking bottom cores and samples of sediment, the effects of the explosion on the lagoon floor, including the persistence and disposition of radioactivity. Work toward this objective was conducted by Russell and Shuler who, using core equipment, bottom samplers, heavy rock dredges, and underwater cameras operated by special winches and other gear installed on a landing craft, obtained 240 bottom samples, thirty-three cores of the lagoon floor, thirty dredging hauls, and a number of photographs of the bottom in the vicinity of the target center. They also took about 350 pounds of the mud from the site of Test Baker for examination by the Atomic Energy Commission. Duplicate samples of all bottom cores were turned over to the Radiochemistry Group for plutonium and fission products analysis and for recording of alpha, beta, and gamma radiation counts. Interest was not exclusively geological, and other members of other groups—among them Donaldson and the radiobiologists, and Morrison, Whitaker and others studying marine invertebrates—were curious about the levels and kinds of radioactivity to be found in the deeper waters of the target area and in the organisms there. The bottom samples and cores, and the biological specimens collected by or for the scientists studying Bikini's invertebrate inhabitants, showed that the target area still held, as the technical report phrased it, "large amounts of radioactive material."

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The geologists reported that, although the Baker Test had stirred up the bottom of the lagoon to distances of 1,000 to 1,500 yards, the maximum disturbance was limited to radius of some 300 yards. The center of blast intensity actually seemed to be, they said, 100 to 150 yards southwest of the former position of LSM 60. Test Baker, the geologists found, "not only increased the depth of the lagoon bottom in the immediate vicinity of the explosion point, but also produced an area of mud which is quite distinct from any other sediment found in Bikini lagoon." The thirty-three cores taken during the Resurvey showed that the bottom at the target area consisted essentially of four layers of materials—a top of target area mud grading into a layer of silt and sand, which rested on a layer of clean, white algal debris, which in turn rested, usually without a transitional zone, on darker, brownish algal debris mixed with mud and sand. The bottom layer was believed to be the original sediment of the bottom prior to Test Baker. Most of the radioactivity at the target area was found in the top layer of mud, although streaks and overlaid deposits were found in the second and third layers. The thickness of the three top layers varied considerably. The coring had to be accomplished between the hulks of the sunken target ships and amid diving operations from the Coucal, and thus the distribution of the core samplings was not ideal in number or pattern. Nevertheless, it was established that the layer of mud which contained the bulk of the radioactive materials was about 5 feet, 3 inches thick at the point below the LSM 60 location, was at a thickness of 8 feet at core No. 33, 125 yards to the southwest, and was thicker than 10 feet—the length of the longest core—at one point near the center of the target area. The average depth of mud was put at about 5 feet. From the data on depths it was calculated that then were "about half a million tons ... of radioactive mud on the lagoon bottom. . . ."

The radioactive mud was at the bottom of Bikini lagoon, 180 feet below the surface of the waters. The waters hid the target ships and the radioactive substance in which they lay, however, and elsewhere the presence of radioactivity at what could be considered significant levels simply was not evident. There was so much of Bikini without apparent disturbance, and so few instances of possible deviation from the expectable, that any questions tended to appear academic. Practically everywhere Bikini seemed too normal to be otherwise, and might, in fact, have been scarcely distinguishable from any neighboring atoll except for the presence of the shacks and towers on the principal islands and the litters of sun-scoured flotsam on the beaches. The Radiological Safety Section, which monitored most of the islands, found few places (except in the patches of tar on the coral and in the beach debris) where beta-gamma readings indicated the presence of radioactivity that would exceed the 24-hour tolerance limit of one-tenth of a roentgen unit. Certain corals were discovered to be dying on the reef between Bikini and Aomoen Islands, corals that had been known to be healthy shortly before Test Baker, yet it was not possible to determine whether these coral clumps had been injured by radioactivity, by oil from the ships of the target array, or—although improbably—by the fresh water of heavy rains during exceptionally low tides. Whitaker's studies of the sea urchins and other invertebrates led to the observation that the specimens examined in the shipboard laboratories—whether taken from places showing no more than normal background radiation or from the most radioactive of Bikini's reefs—were healthy, abundant, and reproducing normally without evidence of aberration or ill effect. One specimen of an unknown species of sea urchin, a specimen brought up by the Navy divers from the flight deck of the Saratoga, was by far the most radioactive invertebrate studied, a Geiger counter reading of its shell and exposed viscera producing a reading of twenty times background. This sea urchin, it was believed, had spent its whole life on the sunken vessel—one of the ships which after Test Baker had been described as a "radioactive stove"—yet dissection disclosed ovaries filled with full-sized eggs altogether usual in number and character.

What, then, could be decided about Bikini a year after Crossroads? If the atoll were considered as a whole, reassurance was there. On the floor of the lagoon, beneath the former target center, lay half a million tons of radioactive mud. But on the islands and reefs and in the waters of the lagoon—even where there existed a mysterious turbidity—life still appeared to thrive and flourish. Even where the faint footprints of the Bikini ghost could be detected they apparently were being dimmed by sun and wind and water. Tiny hermit crabs continued to haul their shells across the sands, making small traces. Big blue and brown coconut crabs stalked as usual through the fallen husks on Namu Island or stared in beady solemnity from the recesses of their burrows amid the roots of palm trees. Moray eels darted about the rocks of the tide pools, and schools of round herring passed in clouds among the coral heads, and with them could be observed fleetingly, now and then, the plump and colorful parrot fish, or the grouper, or the shark. It could not be said that Bikini was sick or that the shocks of 1946 were not being shaken off by the bursting life of a mid-Pacific atoll. Yet doubt lingered. And the difficulty was that no one knew for certain that some insidious malady was not actually at work, in some as yet undetectable way, in the apparently healthy body of Bikini. No one was prepared to certify Bikini as safe for human habitation.

Late in August, the Bikini Scientific Resurvey prepared to evacuate Bikini. Preparations were begun on August 22 when members of the Advisory Board met to discuss logistical problems. In following days the land-based laboratories were put aboard the Chilton, the gear from the officers' and enlisted men's clubs was stowed, drilling and diving operations were suspended, the buildings on Bikini Island were cleaned, closed, and secured, and a final inspection was conducted by Commander Engleman the project officer. The task group of the Bikini Scientific Resurvey departed Bikini on August 29.

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The Radiobiology Group, as did the others, prepared a preliminary report to be incorporated into the 1947 report of the technical director. Also like the others, the Radiobiology Group later developed additional material in its home laboratory, the results to be submitted to the Atomic Energy Commission and made available to the Armed Forces Special Weapons Project. If there were any substantial difference in the Radiobiology Group's view of Bikini in 1947 it is not revealed in specific recommendations or conclusions. There undoubtedly was, however, a difference in the group's interest in Bikini as a field laboratory. In its preliminary report the Radiobiology Group said:

The data . . . indicate a very widespread distribution of radioactive substances in the organisms in and about Bikini Lagoon. In fact, some activity was found in organisms taken from every part of the Bikini area that was sampled. ...

Fission products were found to occur in fish and in invertebrates such as clams, snails, oysters, corals, sponges, octopods, crabs, sea urchins, sea cucumbers, spiny lobsters, and shrimps. They also were represented in the algae found about the lagoon.

Concentration of active substances in fish was greatest in spleen, liver, and feces. Average gross beta-gamma counts per minute per gram of wet tissue for the three above-mentioned materials were 23.5 c/min/gm, 18 c/min/gm, and 14.5 c/min/gm respectively. The kidney and gonads were next in order of active-substance content, exhibiting respective averages of 11.6 c/min/gm and 8.2 c/min/gm. Other tissues extensively sampled, including gills, skin, bone, and muscle, contained fission products in lesser amounts.

The point of view of the Radiobiology Group reflected an interest in the possible values of Bikini as an area, the only such area in the world, in which it would be possible to observe the subtle processes by which small over-amounts of radioactivity were being distributed about a biotic system. The radioactivity to be detected at Bikini in 1947 was at levels low enough to be manageable yet sufficiently high to be traceable through the food chains. When low amounts of radioactivity were found, as the group reported, in "organisms taken from every part of the Bikini area that was sampled," Bikini continued to hold out opportunities for observation. The source of Bikini's irradiation undoubtedly was the target area. If there were, as there seemed to be, a continuing uptake and transfer of fission products from the silt of the lagoon bottom, and if long-lived radioactivity were captured and retained by the tissues of animals and plants, then there was spread out in Bikini a set of problems whose answers lay beyond the scope and period of the 1947 Resurvey.

1 All samples were counted in an aluminum shelf sample holder, with a thin window, argon-alcohol Geiger tube, and a Tracerlab autoscaler circuit. The geometry of this arrangement was about 22 per cent. Total absorption, exclusive of self-absorption, which varied widely for different samples, was approximately 6 mg/cm2. Counter background averaged 18.5 c/m.

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