In early 1946, just before the first atomic bomb tests took place, the Bikinians were relocated to Rongerik Atoll, 120 miles (200 kilometers) to the east.23 Rongerik, however, proved to be no promised land. The atoll had been uninhabited, partly due to its very small size (with a land area less than 0.65 square miles; 1.68 square kilometers), and partly because Marshall Islander folklore held that it was haunted with evil spirits. The move to Rongerik ended what had been an extremely long habitation for the natives of Bikini. Although there are no written records of Bikini’s habitation prior to 1825, archeological discoveries and radiocarbon dating of human artifacts suggest that people had resided on the atoll as early as 2,000 BC (the approximate year that Stonehenge is believed to have been completed).24
FIGURE 8.1. MAP OF HYDROGEN BOMB FALLOUT RANGE. The Bikini Atoll in the Marshall Islands was the site of Castle Bravo, a hydrogen bomb testing mishap that produced unexpectedly high quantities of radioactive fallout, which spread well beyond the anticipated range. Residents of other atolls, over a hundred miles east of Bikini, would require evacuation because of the high radiation doses produced by the fallout. The values shown on the isodose curves are exposure rates in roentgens per hour, at four days post blast. (Source: The Effects of Nuclear Weapons 3rd ed., S. Glasstone and P. J. Dolan, eds. Washington, DC: DOD and DOE, 1977)
Rongerik was not as lush as Bikini, and the islanders began to suffer malnutrition. They were then relocated to Kili Island, even further away from their homeland (425 miles south of Bikini), which turned out to be their greatest blessing in one sense. The Bikinians were already well settled on Kili Island when Shrimp was detonated on March 1, 1954. This was lucky for them, since Rongerik Atoll was situated directly downwind of Bikini on that day. Not so lucky were 28 American servicemen, the only remaining inhabitants of the haunted atoll, who were based at the Rongerik weather station.
Shrimp was detonated at 6:45 a.m. It produced a fireball almost four and a half miles (7 kilometers) in diameter, which was visible over 250 miles (400 kilometers) away (the approximate distance between Washington, DC and New York City). It produced a crater over a mile wide and 250 feet deep (the height of a 25-story building). The mushroom cloud reached a height of 25 miles (40 kilometers) and its cap had a diameter of 62 miles (100 kilometers). The radioactivity-laden cloud contaminated more than 7,000 square miles of the Pacific Ocean (an area nearly the size of New Jersey). But the fallout was not evenly distributed. Areas downwind of the blast received the bulk of it, while locations upwind received virtually nothing. Given the prevailing winds from the west, potentially lethal levels of fallout stretched as far as 230 miles (370 kilometers) east of Bikini Atoll.
Soon after the blast, the US military became aware that radioactivity had escaped beyond their restricted area. Seven hours after the explosion, reports from the Rongerik weather station indicated high levels of radioactivity. The radiation recording instruments placed at the station by the Atomic Energy Commission were reading off scale. This meant that the servicemen at Rongerik (meaning “small lagoon” in Marshallese), and the islanders on nearby Rongelap (“large lagoon”) and Utirik Atolls would need to be evacuated. Also, the off-limits area around Bikini had to be increased from 50,000 to 400,000 nautical square miles (nearly the land area of the state of Alaska) to keep ships and planes from being contaminated. The radius of this new danger zone around Bikini was 500 miles (the distance between Washington, DC, and Detroit).25 Yet, the military did not know about the Lucky Dragon No. 5, so it was never intercepted. Thus, the fishing boat escaped the area and made it back to its homeport, bringing Shrimp’s radioactive contamination with it.26
Three days after the bomb test, fallout had accumulated on some downwind atoll islands to depths of a half an inch (1.27 centimeters) or more. The native inhabitants of the contaminated atolls, as well as the 28 US servicemen from Rongerik, were evacuated to Kwajalein Atoll, the largest atoll in the world, and home to a US military base. The Rongelap natives received a particularly high dose (approximately 2,000 mSv) from the fallout. They had extensive burns on their skin and depressed white blood cell counts. The native inhabitants of other islands had no symptoms, and neither did the servicemen from Rongerik.
At Kwajalein, the contaminated islanders were treated by doctors and were immediately enrolled in a long-term health study led by physicians and scientists from Brookhaven National Laboratories. The health investigation was entitled “Study of Response of Human Beings Exposed to Significant Beta and Gamma Radiation Due to Fallout from High Yield Weapons” (commonly known as Project 4.1).27 Radiation expert Dr. Eugene Cronkite (1914–2001) was assigned leadership of the project on March 8, barely one week after the blast, and before anyone yet knew of the contaminated Japanese fishermen.
With everyone evacuated to Kwajalein, the military thought that it had accounted for all the fallout victims. But then reports of the radioactive fishermen’s arrival in Japan hit the newspapers on March 14. The Japanese government asked the US military to provide the fishermen’s doctors with a breakdown of the fallout’s radioactive composition. But military officials refused because of alleged concern that Soviet scientists would be able to use that information to deduce the mechanism of the hydrogen bomb.28 This explanation does not seem credible, however, since that cat was already out of the bag. The Soviet Union had by then developed its own hydrogen bombs, and had even tested one on August 12, 1953 (six months before Shrimp’s detonation) in northern Kazakhstan.29 Nevertheless, the Americans would offer no information about the radioactive isotopes in Shrimp’s fallout, so the Japanese scientists performed their own analysis from fallout collected from the fishing boat. They determined that it included, at the least, radioactive zirconium, niobium, tellurium, strontium, and iodine.30 Of these, zirconium, niobium, and tellurium have no biological roles, and were, therefore, not of major concern. Strontium and iodine, however, were quite a different story. They were both biologically active. How would they affect health?
DÉJÀ VU ALL OVER AGAIN
Strontium was considered a problem by public health scientists because it is another one of the alkaline earth metals (column 2 on the periodic table), just like calcium and radium; therefore, it would be expected to incorporate into bone. Accordingly, these fishermen, who had actually breathed, ingested, and absorbed the strontium through their skin, ran the risk of becoming the strontium boys, the male equivalent of the unfortunate radium girls. Thus, radiation history appeared to be repeating itself. Suddenly, the experience of the radium girls, three decades earlier, seemed highly relevant to the new strontium problem. All of the radium health studies from that earlier time were revisited, and in order to assess long-term effects, a nationwide hunt was launched to find all surviving radium girls to enroll them in follow-up health studies.31 In 1956, an Atomic Energy Commission official summed up the situation:
Something that happened far in the past is going to give us a look into the future. Why, when these people took in their radium, there was no such thing as strontium-90, and yet they may help us determine today [how much is safe to ingest]. The way I see it, we’re trying to follow up a wholly unintentional experiment that has taken on incalculable value.32
In the end, 520 surviving dial painters were located, and all their medical, dental, and laboratory records were collected and transferred for study to Argonne National Laboratory, a newly established national science and engineering research laboratory outside of Chicago.33 After analysis, all of this data supported the concept that bone seekers, like radium and strontium, behave very similarly, both in their short-term and long-term health effects. One need only adjust for differences in their emission characteristics (half-lives, particle types, energies, etc.) to predict which health effects would be seen for any given exposure.
Iodine posed another tissue-specific threat. Iodine has an affinity for the thyroid gland, a butterfly-shaped organ that straddles the windpipe (trachea) just above the collarbone. The thyroid uses iodine to produce
hormones that regulate body metabolism, an essential function. The problem arises because iodine is relatively uncommon in the natural environment and scarce in many human diets.34 Consequently, whenever the thyroid gland detects some iodine in the bloodstream it snatches it up and stores it away for future use. In a normal individual, the concentration of iodine in the thyroid is 10,000 times the concentration in blood.35
The thyroid is essentially an iodine sponge. This had been known since 1895, the year before radioactivity was discovered by Becquerel, when German physiologist Eugen Baumann (1846–1896) reported that he found extremely high concentrations of iodine in thyroid tissue.36 Understanding this, and knowing that radioactive elements behave chemically just like their nonradioactive counterparts, it isn’t too much of a stretch to predict that radioactive iodine is not going to do good things to the thyroid gland.
Remarkably, the scientific community was slow to realize the unique danger that radioactive iodine posed to the thyroid, and surveillance of the gland was not part of the medical follow-up for any of the victims evacuated from the areas contaminated with Shrimp’s fallout. Years later, Dr. Victor P. Bond (1919–2007), a member of the medical team that the United States sent to treat the fallout-exposed victims, recalled the following: “And quite frankly, I’m still a little embarrassed about the thyroid. [The] dogma at the time was that the thyroid was a radiation-resistant organ … [It] turned out that they had … very large doses of iodine … to the thyroid.” Dr. Eugene Cronkite, Bond’s supervisor and head of the medical team, concurred, noting “there was nothing in the medical literature … to predict that one would have a relatively high incidence of thyroid disorders.”37
By the 1960s, many of the fallout-exposed islanders began to develop thyroid abnormalities, including three thyroid cancers on Rongelap and three on Utirik—a thyroid cancer incidence rate much higher than would normally be expected for a population of just a few hundred people. This caused distrust among the islanders of the medical team, because the team’s leadership had predicted that there would be no thyroid cancers at all.38 The thyroid gland is now understood to be very susceptible to cancer caused by radioactive iodine.
The composition of radioactivity in fallout is no longer considered a state secret since every nation in the world now knows the fundamentals of how nuclear bombs work. Radioactive fallout is composed largely of fission products—the isotopes that result when atoms are split. Although Shrimp was a fusion bomb, fusion bombs are always detonated with a fission bomb trigger, as previously discussed, and the energy of fusion can actually produce more fission reactions. So even fusion bombs emit a substantial quantity of fission fragments. In addition, fallout contains appreciable quantities of the fissionable materials uranium and plutonium, because the fission chain reaction does not reach completion before the core is blown apart.
Fissionable uranium and plutonium atoms can split apart in about 40 different ways, so about 80 different fission fragments (radioisotopes) are theoretically possible. In reality, some are rarely produced, while others are abundant. In addition, most have very short half-lives of less than one minute. These short-lived radioisotopes don’t contribute anything to the fallout hazard. But a number of radioisotopes stay around long enough to cause problems. In addition, some, like the radioisotopes of strontium and iodine, have biochemical properties that cause them to be taken up in the body.
One major component of the fallout from Shrimp that the Japanese scientists overlooked was cesium-137. Cesium occupies column one of the periodic table, making it a chemical cousin of sodium and potassium, both important body electrolytes. Electrolytes are basically dissolved salts. In fact, seawater is an electrolyte solution, and human body fluids are not unlike seawater. The body is particularly dependent on sodium and potassium electrolytes, which are used for numerous physiological functions in all tissues and organs. As such, these electrolytes are quite evenly disseminated among soft tissues. Cesium, like sodium and potassium, is distributed uniformly throughout the body and doesn’t seek out any particular tissues or concentrate in any one organ, although it is somewhat enriched in muscle. So that’s not the basis for its health effects. Rather, the problem with cesium-137 is simply that it hangs around in the environment for a very long time (half-life = 30 years). The only silver lining to this cloud is that cesium, again like sodium and potassium, is highly soluble in water (hence, its electrolyte properties), and, therefore, is usually quickly dissolved by rainwater, swept into rivers, and deposited in the ocean, where currents mix and dilute it down to very low concentrations.39
The bottom line is that the radioisotopes in fallout with a significant potential to affect health are few: iodine-131 (8-day half-life), strontium-89 (52-day half-life), strontium-90 (28-year half-life), and cesium-137 (30-year half-life). As can readily be seen, the iodine-131 represents a relatively short-term risk, but strontium-90 and cesium-137 can persist for years.
For the Japanese fishermen, the treatment turned out to be as bad as the disease. Sadly, much of the blood they received during their transfusion therapy was contaminated with hepatitis virus, so most of them (17 out of 22) came down with hepatitis (i.e., liver disease).40 To make matters worse, they were neither told of nor treated for their liver disease,41 possibly because the doctors wanted to cover up their mistake, and many of the fishermen ultimately died from liver-related causes. A study initiated to follow their health over time, in order to learn more about radiation sickness from radioisotopes, eventually broke down because of the fishermen’s distrust of medical authorities, and because their underlying liver disease would have compromised the validity of the findings anyway.42 During the aftermath of the Lucky Dragon No. 5 episode, Japanese/American relationships reached a postwar low, especially since the American authorities insisted that the Japanese doctors share the culpability for the fishermen’s health problems because they had administered the virus-contaminated blood.43 After intense negotiations, each fisherman received $5,550 (about $49,000 in 2015 dollars) in compensation from the US government, in exchange for agreeing to push their legal claims no further.
LAND OF MILK AND HONEY … AND COCONUT CRABS
The evacuated islanders were eventually resettled on uncontaminated atolls. Rongelap’s people were placed on the island of Ejit in Majuro Atoll. While they waited to return to their home atoll, the US government conducted environmental studies on Rongelap and monitored the gradual decrease in its environmental radioactivity levels. The natives were finally returned to Rongelap in 1957. They were told that the island itself was now safe, and the local foods were safe to eat.44 But the local foods turned out not to be safe.
Besides breathing and absorbing fallout through the skin, another major means by which fallout enters the body is through food ingestion. The ingestion route is particularly important for those radioactive elements that can enter the food chain—the series of steps that lead from food production to consumption. Both iodine and strontium fall into this category.
There’s some good news and bad news when it comes to iodine exposure through the food chain. As it turns out, we get most of our dietary iodine through dairy products. That’s because cows get their iodine from eating grass and some of that iodine goes into their milk. Thus, nursing calves get the iodine they need through consumption of milk, until they start eating grass on their own. When we intercept the milk for dairy products we abscond with that iodine for our own bodies. Once we ingest those dairy products, the iodine goes to our thyroids. What this means is that if a cow is eating fallout-laden grass, we’re consuming radioactive iodine (i.e., iodine-131) when we drink its milk (or eat dairy products). This is bad news if we’re drinking a lot of iodine-131 contaminated milk right after a fallout event. The good news is that, after a brief period, the short-lived iodine-131 decays away so that the grass, the cow, and even the milk, no longer contain hazardous levels of iodine-131. (Since the half-life of iodine-131 is just eight days long, waiting three months before eating contam
inated food reduces exposure to its radioactivity by 99.9%.) For iodine-131, it turns out that the best protection is temporary abstinence from locally produced food products, especially milk.
FIGURE 8.2. COCONUT CRABS. This extremely large species of omnivorous terrestrial crab (Birgus latro) is native to the South Pacific. It has the ability to climb palm trees, crack coconuts with its very powerful claws, and eat the coconut meat. Radioactive strontium in the soil of the Marshall Islands from nuclear bomb testing fallout was taken up by palm trees and concentrated in their coconuts. Unfortunately, both the crabs and the coconuts formed a large part of the Marshall Islanders’ diets.
Strontium has its own unique food-chain story, reminiscent of the watch painter’s unique problem with radium ingestion. In February 1958 (one year after the return of the islanders to Rongelap), US Navy scientists decided to test the Rongelap coconut crab population for radioactive contamination. They found boatloads of radioactivity.
Coconut crabs (Birgus latro) are very large terrestrial crabs, actually resembling lobsters more than crabs. They have claws powerful enough to crack coconuts, their major food source. The coconuts are rich in the calcium that the crabs need to sustain their large fast-growing shells (exoskeletons). Palm trees absorb the calcium from the ground and concentrate it in their coconuts. And strontium, as we already know, is a dead ringer for calcium as far as biochemistry is concerned. Consequently, the crabs of Rongelap had become highly radioactive from the strontium-90 contamination. To make matters worse, the islanders considered the coconut crabs a delicacy, and had been eating lots of them ever since their return to the atoll a year earlier. Then, in June 1958, the Rongelap Islanders were told by the Navy not to eat their local coconut crabs anymore, yet another assault on their native lifestyle.45
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