Oceanus v50 n1 English

Fukushima and the Ocean

What have we learned from this unprecedented release of radioactive contaminants to the ocean?

Vol. 50, No. 1, Spring 2013

Managing Editor: Lonny Lippsett Editors: Ken Kostel, Kate Madin, Kaoru Saeki, Cherie Winner Japanese Translator: Naoko Ushimaru-Alsop

Contents Vol. 50, No. 1, Spring 2013, ISSN 0029-8182

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How Is Fukushima’s Fallout Affecting Marine Life?

Seafood Safety and Policy

Leadership Program in Sustainable Living with Environmental Risk, Yokohama National University

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Science Council of Japan

Health Risks

Communicating Disaster

For information, contact Lonny Lippsett, WHOI, Woods Hole, MA 02543; llippsett@whoi.edu; phone: 508-289-3327; fax: 508-457-2180.

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Japan’s Triple Disaster

Radioisotopes in the Ocean

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Woods Hole Oceanographic Institution is an Equal Employment Opportunity and Affirmative Action Employer.

This issue of Oceanus was funded by The Japan Foundation Center for Global Partnership and the Elisabeth W. and Henry A. Morss, Jr., Colloquia Endowed Fund, which also contributed to the Fukushima and the Ocean symposia in Tokyo and Woods Hole. Other contributors for the symposia were: The Gordon and Betty Moore Foundation The Center for Risk Management and Safety Sciences, Yokohama National University Oceanographic Observation Center, Tokyo University of Marine Science and Technology The Center for International Collaboration, Atmosphere and Ocean Research Institute, University of Tokyo Center for Marine & Environmental Radioactivity, Woods Hole Oceanographic Institution Policy Alternatives Research Institute, University of Tokyo

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Cross-border Collaboration in Times of Crisis People around the world were just beginning to absorb the terrible news of the earthquake and tsunami off Japan on March 11, 2011, when reports appeared about power losses at the Fukushima Dai-ichi nuclear power plant. For days, all we could do was watch, as images of the first explosion at the plant appeared on TV and elevated radiation levels were recorded nearby. It was a confusing time, as evacuation orders were issued to those living close by, while Tokyo and the rest of the world waited.

The disaster brought back memories for both of us of April 1986, when the nuclear power plant at Chernobyl exploded.

Ken, then a graduate student at Woods Hole Oceanographic Institution (WHOI), was called to action to study the spread of radioisotopes in the Black Sea. Mitsuo, a postdoctoral scientist at the University of Rhode Island, measured the spread of radioisotopes from Chernobyl through the air to islands across the North Pacific.

But Chernobyl took place hundreds of kilometers from the ocean. Fukushima sits on the coast. While explosions from overheating reactors at the Dai-ichi plant sent radioisotopes into the atmosphere and across the Pacific, water desperately needed to cool the reactors flushed directly into the ocean.

By March 21, TEPCO, the owner/operator of the plant, was reporting levels of cesium radioisotopes in the ocean that far exceeded anything we had measured post-Chernobyl. By early April, it was clear that this was an unprecedented event for the ocean. Questions mounted in the minds of scientists and the public. Was this a local spill or a global threat? How would humans, ecosystems, and food be affected? And when would any threats end?

It quickly became clear that understanding the immediate and long-term consequences of this event was more work than any one laboratory or country could handle. In May, we met in Belgium, where we learned that we shared a common background working on Chernobyl, as well as a common concern that we needed to act immediately and coordinate our efforts.

Mitsuo became the point of contact between the Japanese and international scientific communities, while a group at WHOI led by Ken secured private funding, chartered a ship, and organized a multidisciplinary international research cruise, all in a record six weeks. The mission of that cruise was to survey the waters and marine life off Japan—to capture, before the knowledge was lost forever, the initial stages of critical, rapidly changing phenomena happening in the ocean.

Two years later, while there are still many basic questions to answer, we now know that the impacts of the Fukushima disaster to human health are largely localized to the waters near Japan, despite the spread of debris across the Pacific. Fisheries close to Fukushima remain closed, as contamination levels remain stubbornly high in some seafood.

During our scientific investigations, we also learned that the public was confused and skeptical of officials and scientists. To the public, we seemed to be speaking a foreign language of becquerels and sieverts and couldn’t answer simple questions such as, “When the fish will be safe to eat?”

So we joined forces once again to bring some of our knowledge to the public. We assembled 90 experts from ocean and health sciences, policy, economics, and the media in a two-day symposium at the University of Tokyo to review what we had learned and discuss the most pressing issues for continuing study, including seafood safety and the health effects of low-level radiation. We also brainstormed on how best to communicate a complicated science and the nature of risk to the public. We held two public forums on “Fukushima and the Ocean” in Tokyo in November 2012 and again in Woods Hole in May 2013. This issue of Oceanus compiles our findings and discussions.

Certainly, we hope we never have another disaster like Fukushima, but it is our responsibility to learn from these events and pass on that understanding to those living both in the shadow of Fukushima and across this ocean planet.

Ken Buesseler Center for Marine & Environmental Radioactivity, Woods Hole Oceanographic Institution

Mitsuo Uematsu The Center for International Collaboration, Atmosphere and Ocean Research Institute, University of Tokyo

Ken Buesseler (left) and Mitsuo Uematsu consult on a train to Yokohama, where they would rendezvous with the multinational, multi-institutional team of scientists they organized in June 2011 to investigate the spread of radioisotopes from Fukushima into the ocean and marine life.

Ken Kostel/WHOI

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Japan’s Triple Disaster

By David Pacchioli

T

he chain of calamity now known as Japan’s Triple Disaster began with a massive rupture in the ocean floor.

At 2:46 p.m. on March 11, 2011, below the seafloor off the country’s northeast coast, the Eurasian and Pacific tectonic plates, which grind against one another at the bottom of the Japan Trench, slipped their grip. It’s a common enough occurrence in what is one of the world’s most seismically active regions. A megathrust fault there runs for some 500 miles undersea and experiences hundreds of lesser tremors every year.

This one, however, was different. At magnitude 9.0, what became known as the Tohoku earthquake was the world’s fifth largest since modern records began around 1900. In Tokyo, less than 200 miles from the epicenter, the trembling lasted a full six minutes. When it finally stopped, parts of the main island of Honshu had moved eight meters, or 26 feet, to the east.

Damage from the earthquake itself was just the start. The tremendous upthrust from the seafloor unleashed a series of enormous tsunami waves, the first of which struck the coast within an hour.

Images of the devastation still stagger. Cars and boats perched atop buildings. Houses floating in the sea. The haunted faces of survivors, and of exhausted rescue workers searching through mountains of splintered debris. Entire villages obliterated.

At the Fukushima Dai-ichi nuclear power plant, commissioned in 1971 on the coast 140 miles north of Tokyo, the earthquake had already knocked out electricity, but emergency backup systems seemed to be functioning properly. Then the tsunami hit. An image captured by a plant security camera freezes the moment. It shows a small ship idling in the shallow harbor in front of the reactors, safe within the arm of a 19-foot sea wall. Just behind the wall, looming like an overwrought computer-generated image, is that enormous curling wave.

Topping 45 feet, the tsunami mocked all precautions. The plant was quickly flooded, and its backup diesel

2:46 p.m. March 11, 2011 Some 45 miles east of Japan and 18.6 miles below the seafloor, a 310-foot-long fault ruptured, releasing the equivalent energy of a 100-megaton explosion. The magnitude-9 earthquake transmitted seismic waves that shook Japan.

Minutes Later

50 Minutes Later

March 12, 2011

The quake lifted the seafloor as much as 16 feet over a 5,800-square-mile area, displacing gigatons of seawater and creating tsunami waves. Traveling 500 miles per hour, the tsunami struck the northeast coast of Japan, reaching heights up to 49 feet.

In Fukushima, the Dai-ichi nuclear plant withstood shaking from the quake. But a tsunami overwhelmed its 19-foot seawall and flooded emergency generators that pumped water to cool the reactors. Radioactive decay in the reactors continued to generate heat.

Reactor meltdowns caused explosions that released radioactive gases to the atmosphere. To cool reactors, workers flooded the plant with millions of gallons of water. It flushed into the sea, beginning the release of an unprecedented amount of radioisotopes to the ocean.

generators incapacitated. The complete power loss launched days of spiraling catastrophe that riveted the world, culminating in the largest nuclear disaster since Chernobyl in 1986.

Without their cooling systems, three of the plant’s six reactors began to overheat. The buildup of hydrogen gas generated by melting nuclear fuel resulted in colossal explosions in these three units and damage to the containment structure of a fourth reactor. Tens of thousands of people left their homes as the Japanese government set up widening evacuation zones based on shifting predictions of radioactive fallout from these explosions. Meanwhile, amid frantic efforts to forestall a complete meltdown, thousands of tons of water were poured onto the reactors from water cannons, fire trucks, and helicopters.

That water picked up radioactive isotopes from the reactors and eventually drained to the sea.

A swath of devastation

Ten nail-biting days after that first wave hit, the immediate nuclear crisis was contained. But the lasting impacts of the triple disaster are practically incalculable. The tsunami alone killed 20,000 people, and displaced more than 150,000 others.

Economic losses have been estimated at anywhere from $250 billion to $500 billion USD. Merely cleaning up the debris scattered along the coast, some 22.5 million tons of it, is a task that will require years.

The larger legacy of the nuclear disaster may take decades to unfold. Radioactive fallout has led to evacuation of a 300-square-mile area around and northwest of the plant, rendering 150,000 people homeless. Widespread contamination of water, soils, crops, and vegetation has necessitated expensive cleanup efforts and banning of foodstuffs, and has sparked ongoing health concerns, particularly for children living within affected areas.

Uncertainty about acute and ongoing radioactivity exposures has heightened public anxiety, crippled local economies, and jeopardized the future of nuclear power in Japan.

Finally, frustration and anger at the response of Japanese authorities to the disaster, including bungled communications and withholding of information during and after the crisis, has severely damaged public trust in Japanese government and industry officials, as well as Japanese scientists.

Radioactivity in the ocean

It could’ve been worse, said Ken Buesseler, a marine chemist at Woods Hole Oceanographic Institution (WHOI). Because of prevailing weather patterns and the coastal location of the plant, an estimated 80 percent of the radioactivity released by the accidents at Fukushima Dai-ichi wound up not on the densely populated Japanese mainland but in the sea. As a result, although thousands of people living near the plant may have suffered some level of exposure, tens of millions of Japanese were spared.

On the flip side, the huge amount of radioactive contamination to the western North Pacific, delivered via atmospheric fallout and direct discharge of cooling waters, created an unprecedented challenge for the ocean—and for ocean scientists.

What, exactly, had the ocean absorbed? What would the immediate impacts be on sea life at every level, from microbes to fish to humans? Where would all that radioactivity go, and

4 Oceanus Magazine Vol. 50, No. 1, Spring 2013 | www.whoi.edu/oceanus

where would it eventually wind up? A host of Japanese researchers, and their counterparts from around the world, mobilized to take on these questions.

At Woods Hole, Buesseler had watched the evolving disaster with particular interest. He has spent a career studying radioactive isotopes in the ocean, beginning as a graduate student in the MIT/WHOI Joint Program measuring traces of plutonium left in the Atlantic from Cold War-era nuclear weapons tests.

In April 1986, shortly before he was to receive his Ph.D., he got word of the nuclear disaster at a place called Chernobyl. He quickly made his way to Turkey to begin sampling radioisotopes in the Black Sea. In the decades since, Buesseler has focused mostly on radioisotopes that are present in the sea because of natural geochemical phenomena, and on refining the techniques that allow oceanographers to use these elements to trace currents and understand processes that go on in the ocean.

Sampling the sea

As events at Fukushima unfolded, Buesseler monitored data that were beginning to be released by the Tokyo Electric Power Co., or TEPCO, operators of the Dai-ichi plant. It took some time for the scale of the contamination to become clear.

Finally, on April 6, levels of cesium-137 measured at outlets close to the plant peaked at a shockingly high concentration of around 60 million becquerels per cubic meter. (One becquerel equals one radioactive decay event per second. It is named after Antoine Henri Becquerel, who co-discovered radioactivity.)

“That’s when we started to get worried,” Buesseler remembered. “At that level, you could already say this was an unprecedented release to the ocean.”

Immediately, Buesseler began strenuous efforts to mount a research cruise to the area. (See Page 6.) Within weeks he had organized an international team of scientific colleagues, and— with a $3.7 million grant from the George and Betty Moore Foundation—the necessary funding. He chartered the research vessel Ka’imikai-o-Kanaloa, nicknamed the K-O-K, from the University of Hawaii, and on June 6, with final permissions to sample in Japanese waters yet to be granted, the ship left Yokohama on a two-week sampling mission. With Japanese vessels taking coastal measurements, Buesseler and his team focused their efforts farther offshore to paint a bigger picture about the large-scale transport and ultimate fate of the radioisotopes.

In May and early June, cesium-137 concentrations measured along the coast had dropped off precipitously, Two years after the disaster at the Fukushima Dai-ichi nuclear power plant, workers near the No. 4 reactor use a radiation monitor to measure elevated levels of radioactivity: 114 microsieverts per hour.

as most of the cesium initially released was washed out to sea.

Cesium-137 is soluble in seawater, Buesseler explained, so it quickly disperses down and out into the ocean. “If you shut off the source, you start to decrease the concentration of cesium-137 immediately,” he said.

Seafood risks?

Sampling from the K-O-K subsequently confirmed that the powerful Kuroshio Current, running northeast along the coast like the Gulf Stream in the Atlantic Ocean, carried most of the radioactivity out into open waters of the North Pacific.

Blanketing a wide area, Buesseler and his colleagues sampled seawater, plankton, and small fish at the surface and at varying depths. What they found was in some ways encouraging.

Levels of cesium in these offshore waters, though higher than normal, were below limits considered risky for human or animal exposure. The levels were, however, high enough to be of some concern if they accumulated in fish and were eventually consumed in seafood. (See Page 12.)

For the Japanese, who eat more seafood than perhaps any other modern nation, such concerns are magnified. Reports of contaminated catch off Fukushima led quickly to closure of fisheries there and in surrounding precincts. Attempting to ensure consumer safety and calm fears, the Japanese government in April 2012 further reduced limits for acceptable radioactivity levels in fish, which were already among the lowest in the world. But although the vast majority of fish now being taken off the coast of Japan meet even this stringent standard, some contaminated fish continue to be caught years later.

Troublingly, as Buesseler pointed out in a study published in the journal Science in October 2012, levels of cesium present in a wide range of fish are no longer declining or are decreasing only slowly—suggesting that cesium is still emanating from the nuclear power plants or contaminated sediments on the seafloor.

Some Japanese coastal fisheries remain closed, and public anxiety remains high. The economic cost has been enormous,

with estimates of fishing industry losses ranging from $1.3 billion to $2.6 billion USD in 2011 alone. (See Page 16.)

Lingering questions

Almost two years after the Fukushima disaster, basic questions remain. How much radioactivity was released into the ocean? What is the long-term fate of those contaminants, and what impacts will they have on the marine environment?

What, if any, are the continuing sources of radioactivity—and when will they end? Is Japanese seafood safe?

Connected to these questions are concerns about radioactivity and human health. What are the risks of low-level exposure to both long-lived isotopes such as cesium-137 and fast-decaying ones such as iodine-131? (See Page 20.)

And then there are questions about the official response to the disaster: What went wrong? What has been learned? What could be done differently? Ongoing safety concerns and widely expressed public frustration point to failures in crisis communications, and the challenges of communicating effectively about complex scientific realities—especially those involving risk. (See Page 24.)

To address the current state of these and other questions, Buesseler and his Japanese colleague Mitsuo Uematsu of the University of Tokyo convened a two-day Fukushima and the Ocean colloquium in Tokyo in November 2012. Some 90 invited attendees from ten countries included ocean and atmospheric scientists, health physics experts, policymakers, and media professionals. The goal, Buesseler said in his opening remarks, was “not to alarm or to blame, but to present a scientific review of what we know and don’t know about the contaminants released at Fukushima, their fate in the ocean, and their potential to impact marine ecosystems and human health.”

This issue of Oceanus reports on this important conference, the catastrophe’s far-reaching repercussions, and lessons to be learned from Japan’s Triple Disaster.

EPA/ISSEI KATO / POOL

Radioisotopes in the Ocean

What’s there? How much? How long?

By David Pacchioli

T

he release of radioisotopes from the Fukushima Dai-ichi nuclear power plant in March 2011 amounts to the largest-ever accidental release of radiation to the ocean.

It came mostly in the form of iodine-131, cesium-134 and cesium-137, the primary radioisotopes released

from the reactors, reported Ken Buesseler, a marine chemist at Woods Hole Oceanographic Institution.

All of these substances can cause long-term health problems, said Buesseler, but iodine-131 has a half-life of just eight days and so would be effectively gone from the environment in a

matter of weeks. It was cesium-134 and cesium-137, with their half-lives of two and 30 years, respectively, which would remain in the ocean for years and decades to come.

In fact, most of the cesium present in today’s oceans, Buesseler noted, is a remnant of atmospheric nuclear weapons testing conducted by the United States, France, and Great Britain during the 1950s and ’60s. Lesser amounts are attributable to the Chernobyl nuclear accident in 1986 and to local sources, such as the dumping of low-level waste from England’s Sellafield nuclear facility into the Irish Sea. Prior to Fukushima, however, the levels of cesium-137 off the coast of Japan, as cataloged by Michio Aoyama at the Meteorological Research Institute in Japan and others, were among the world’s lowest, at around 2 becquerels per cubic meter (1 becquerel, or Bq, equals one radioactive decay event per second). Against this background, the concentrations measured in early April of 2011 were all the more alarming. At Photos by Ken Kostel/WHOI

the source waters closest to the Fukushima Dai-ichi plant operated by the Tokyo Electric Power Co., concentrations of up to 60 million becquerels per cubic meter were reported, high enough to cause reproductive and health effects in marine animals.

Most of the cesium from Fukushima came from the millions of gallons of water poured onto the reactors during efforts to cool them, which subsequently flowed into the ocean as runoff or via groundwater. One major leak from flooded buildings at the plant also added cesium to the ocean. Once the leak was plugged in early April, cesium levels close to shore fell off dramatically, Buesseler said. They did not, however, fall out of sight.

“Dilution due to ocean mixing should be enough to cause a decrease in concentration down to background levels within a short period of time,” Buesseler told his audience at the Fukushima and the Ocean conference in November 2012.

“Yet all the data we have show that measurements around the site remain elevated to this day at up to 1,000 becquerels per cubic meter.”

He hastened to put that number into context. “A thousand becquerels is not a big number for cesium. Just for comparison, that’s lower than the U.S. Environmental Protection Agency’s limit for drinking water. At that level, Buesseler stressed, the cesium in Japanese coastal waters is safe for marine life and for human exposure.

“It’s not direct exposure we have to worry about, but possible incorporation into the food chain,” he said. That, and the ongoing high levels of radioactive cesium. “The fact that they have leveled off and remained higher than they were before the accident tells us there is a small but continuous source from the reactor site.”

The routes and rates of radiation

Away from the coast in the open ocean, the radioactivity that showed up first came from fallout from the atmosphere carried out to sea by winds. The winds limited radioactive exposure on land, as more than 80 percent of the fallout fell on the sea.

Only a few weeks after the accident, a research cruise undertaken

by Makio Honda and colleagues at the Japan Agency for Marine-Earth Science and Technology, or JAMS-TEC, detected low levels of both cesium-137 and cesium-134 some 1,900 kilometers (1,180 miles) from Fukushima, from radioactive gases carried out to sea by winds. The importance of the shorterlived cesium-134 isotope, Buesseler said, was that it offered definitive proof that the contamination had originated from Fukushima. Cesium-134 is not naturally present in the ocean, and it has a half-life of only two years. Any amount of it introduced by weapons testing or other pre-Fukushima sources would have long since disappeared.

In the weeks after the Fukushima nuclear disaster, Ken Buesseler (far left), a marine chemist at Woods Hole Oceanographic Institution, organized an expedition with scientists from different fields and institutions to investigate radioisotopes from the damaged nuclear plant that ended up in the ocean and marine life. They used nets to sample organisms and instruments such as the one at right to collect more than 1,500 water samples in 30 locations off Japan. Water and biological samples were sent to 16 labs in seven countries to detect levels of a variety of radioisotopes.

In June 2011, Buesseler led a quickly organized expedition aboard the research vessel Ka’imikai-o-Kanaloa that took a comprehensive look at the fate of Fukushima radiation both in the open ocean and in marine life. Beginning 600 kilometers offshore and coming within 30 kilometers of the crippled nuclear plant, the research team sailed a sawtooth pattern, gathering water samples from as deep as 1,000 meters, and collecting samples of phytoplankton, zooplankton, and small fish. (See Page 12.) They also released two dozen drifters to track currents. These instruments move with ocean currents over months and report their positions via satellite.

Like their Japanese colleagues, Buesseler’s team measured elevated levels of both cesium-137 and the telltale cesium-134 in the water they collected. These levels varied widely across the sampling area, however, which indicated the complexity of the currents at play—dominated by the mostly eastward flow of the mighty Kuroshio Current, the Pacific Ocean’s equivalent of the Gulf Stream in the Atlantic.

“The first thing we noticed was that when we got to the Kuroshio, we lost the cesium-134 signal,” Buesseler said.

“That confirmed that the Fukushima radioactive fallout from the atmosphere did not reach these more southern latitudes.”

The scientists believe the Kuroshio acted as a barrier, blocking radioisotope-contaminated waters from flowing through it and to the south.

An Unprecedented Release Of Radioisotopes to the Ocean The amount of cesium-137 radioisotopes from the Fukushima disaster in surface ocean waters was 10,000 to 100,000 times greater than amounts that entered the ocean from the Chernobyl accident or atmospheric nuclear weapons tests.

100,000,000

10,000,000

1,000,000

100,000

10,000

Becquerels/ cubic meter

1,000

100

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Fukushima 2011 Levels of radioisotopes measured from March to July 2011 in surface ocean waters off the coast of Japan following the disaster at the Dai-ichi nuclear power plant located on the coast. Radioisotopes entered the ocean from atmospheric fallout and from water used to cool damaged reactors, which flushed into the ocean.

Chernobyl 1986 Levels of radioisotopes measured in 1986 in the Baltic Sea and Black Sea from atmospheric fallout following the disaster in the Chernobyl Nuclear Power Plant. The plant was located in Ukraine, hundreds of kilometers inland.

Weapons Testing 1960s Levels of radioisotopes from fallout from atmospheric nuclear weapons tests, measured in the 1960s off Japan. Levels were higher in the immediate areas near Bikini Atoll and others places where weapons were detonated.

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Starting 375 miles off Japan, researchers on the Ka’imikai-o-Kanaloa measured radioisotope levels in various locations. They found that the Kuroshio Current blocked the southward flow of radioisotopes.

Highest levels concentrated south of Fukushima, where currents trapped contamination in a swirling eddy.

As expected, he said, the highest levels of radioactivity were measured closer to the shore. Surprisingly, these high levels were found not at Fukushima but much farther south, off the coast of neighboring Ibaraki Prefecture.

The drifter data showed that this seeming anomaly was the result of a large circular flow, or eddy, that had trapped contamination close to shore south of the plant.

Over time, the researchers’ drifters helped to establish the routes and rate of radiation transported out into the wider ocean and revealed the complexity of currents in the region.

A year after the drifters were released, WHOI oceanographer Steve Jayne showed that their circuitous tracks extended halfway across the Pacific, remaining mostly north of the Kuroshio Current. Combined with surface-water samples taken by commercial “ships of opportunity” in a program organized by Aoyama, these data show cesium mixing down into the ocean and flowing east at a rate of about 7 kilometers per day. At that rate, Buesseler said at the November 2012 conference, it would take another year for small but measurable amounts of cesium to show up off the U.S. West Coast.

Modeling the ocean

Lacking dipsticks in the ocean to measure the ongoing dispersal of radioisotopes, or regular research cruises, scientists must rely on mathematical ocean models to predict where radioactivity from Fukushima is f lowing. These incorporate the best-known physics of ocean current dynamics, but modeling the unique currents off Japan’s Pacific coast can be a frustrating task, JAMSTEC’s Yukio Masumoto said at the Tokyo conference.

In particular, the waters off Fukushima are squeezed between the Kuroshio, which flows northeastward near Chiba Prefecture and then turns eastward, and the colder and fresher Oyashio Current, which flows south from the Arctic Ocean.

The collision of these two major currents in the western North Pacific creates a region of dynamically mixing waters that makes for prolific fishing grounds, Masumoto said, and also produces 100- to 1,000-kilometer-wide eddies and complicated small-scale effects, all of which must be incorporated into any large-scale simulation. “In addition to these open-ocean phenomena,” he said, “we must also account for coastal phe-

Levels of cesium-134 in the surface of the Pacific Ocean in June 2011 Dai-ichi nuclear power plant

Becquerels/ cubic meter

0–3 10–30 100–300 1,000 3,000

Data from Steve Jayne/WHOI Illustration: Jack Cook/WHOI

Kuroshio Current

ship track

nomena, and for the interactions Ka’imikai-o-Kanaloa between the two.”

To take up this challenge, JAMSTEC has developed a nested system of models. Some cover wider territory, sacrificing detailed resolution; others provide more details by focusing in on smaller areas.

The base model, called the Japan Coastal Ocean Prediction Experiment, or JCOPE, is a global-scale ocean simulator.

Contained within it is JCOPE2, a regional model covering Of the fracjust the Northwest Pacific and incorporating observed data tion delivered as on temperature and salinity in order to produce realistic ocean atmospheric fallout, most currents. Tucked within the regional model, and offering still estimates lie between 10 and 15 finer resolution, is JCOPET, a coastal model that can simulate PBq. The numbers for direct discharge, tidal effects.

3 to more than 15 PBq, are much less certain, Buesseler noted.

Masumoto stressed that the accuracy of each of these disNor do these total numbers account for the release of other persion models—and several others currently being run at his isotopes from lingering plant discharges, including stronand other institutions in Japan and elsewhere—depends largetium-90, which, although present in quantities much lower ly on actual measurements put into the models before they are than cesium, is of concern: It accumulates in the bones of fish set in motion. that could be eaten.

“The observed data are quite limited in time and space, and To understand the ultimate fate of Fukushima cesium in we cannot say which model is the best,” Masumoto said—esthe oceans, scientists will have to uncover not just the paths pecially given the ongoing uncertainty about the amount of ra- and speed of ocean currents that transport cesium across the dioisotopes that entered the ocean.

Pacific, but also how cesium mixes into deeper layers of the Buesseler reviewed the range of current estimates of the ocean and how much accumulates in particles of organic detotal cesium releases. Their totals vary widely, he noted, but tritus, or “marine snow,” that sinks down and settles on the are “beginning to converge” on a total cesium-137 release of seafloor. Smaller but ongoing radioactive inputs from rivers between 15 and 30 petabequerels (1015 Bq). In comparative and groundwater in the vicinity are being reported by Japanese scientists, and will also have to be considered. Although some terms, he said, this is slightly more than the amount put into of these puzzle pieces are beginning to fit together, Buesseler the sea by Chernobyl—although the total environmental resaid, significant gaps in knowledge remain. lease from that accident, at 85 PBq, was much higher.

Woods Hole Oceanographic Institution

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ABCs of Radioactivity A Long and Winding Road to Achieve Stability

T

o the average layperson, “radioactivity” is a harsh and For example, one of the most common naturally occurring scary word. But the fact is that radioisotopes, both naturadioisotopes, uranium-238, has 92 protons and 146 neutrons. ral and artificial, are all around us. And for marine sciIt decays into thorium-234 (90 protons, 144 neutrons), which entists in particular, they are important tools. Oceanographer decays into protactinium-234 (91 protons, 143 neutrons), and Claudia Benitez-Nelson reviewed some of the fundamentals at so on. The half-lives for each of these radioisotopes, respecthe start of the Fukushima and the Ocean conference in Tokyo tively, are 4.468 billion years, 24 days, and 1.2 minutes—and in November 2012. each of these elements chemically reacts in a different manner To begin at the beginning, radioactivity is a spontaneous (see next page). emission of radiation resulting from changes in the nucleus “Because that half-life differs from one radioisotope to the of a chemical element, said Benitez-Nelson, who earned her next, we can use it as a simple clock to study a host of ocean Ph.D. from the MIT/WHOI Joint Program in 1999 and processes that take place across different timescales, from days now directs the marine science program at the University of to years to millennia,” Benitez-Nelson said. So-called radioacSouth Carolina. “We radiochemists have a whole suite of eltive “tracers” are present in the ocean for eons—some formed ements that we consider by the interaction of inradioactive. They’re simcoming cosmic rays from ply unstable. In the prospace with atmospheric cess of getting rid of that gases, and still others ininstability, they release troduced by human acenergy to the surrounding tivities. These tracers help environment in the form scientists unravel how fast of radiation.” ocean waters mix, how That radiation comes quickly groundwater from in two broad types. The land enters the ocean, and non-ionizing type, which how rapidly carbon and includes visible light and other elements are cycled microwaves, lacks enough through air, sea, seafloor, oomph to create charged and continents. ions, and thereby to alter Several common natuthe structure of an atom. rally occurring radioiso—Ken Buesseler It poses little threat to our topes—uranium, thorium, health. Ionizing radiaand potassium—are altion, however, can actually ways present in seawater. change the atomic structure of living tissue—killing cells or In fact, noted Benitez-Nelson, the amounts of these isotopes making them cancerous. That’s why we try to avoid direct expresent in the ocean are thousands of times higher than those posure to medical X-rays and the sun’s ultraviolet rays. of even the largest human sources of radioactivity.

All radioisotopes—also called radionuclides—lose excess Ken Buesseler, a marine chemist at Woods Hole Oceanoenergy by emitting ionizing particles such as neutrons, prographic Institution, put it this way: “We live in a sea of radiotons, electrons, or photons. In the process, these so-called paractivity, but this does not present a problem to us or to sea life ent radioisotopes transform, or decay, into daughter isotopes because the radioactive elements found in our oceans are at containing different numbers of protons and neutrons. Daugh- such minute concentrations.” As Buesseler added, “The danger ters with the same number of protons are isotopes of the parent is in the dose.” (See Page 20.) element; daughters with a different number of protons are ac—David Pacchioli tually different elements, with different chemical properties.

Each change along the way, Benitez-Nelson noted, follows a unique timetable, or half-life. The half-life of an isotope is the time it takes for one-half of the atoms in a given sample to decay. This daughter isotope can decay into another radioisotope, or the daughter isotope, that will continue the radioactive decay chain or decay into a stable element that ends the chain.

“We live in a sea of radioactivity.

The danger is in the dose.”

10 Oceanus Magazine Vol. 50, No. 1, Spring 2013 | www.whoi.edu/oceanus

Radioactive Decay Chains Thorium-234 90 protons 144 neutrons

Uranium-238 92 protons 146 neutrons

238

U

4.5 billion yrs

234

Protactinium-234 91 protons 143 neutrons

Th

24 days

234

m 1. 2

234

Atoms

Atoms are made of protons, neutrons and electrons. The number of protons determines what element it is. Atoms have the same number of protons.

Atoms with different 230 numbers of neutrons are called isotopes.

Radioactive elements, called radioisotopes or radionuclides, are unstable.

They spontaneously “decay,” releasing particles and/or energy.

In the process, “parent” isotopes become “daughter” isotopes. These may become parent isotopes to their own daughter isotopes.

25

0 0,

00

y

Pa

,0

00

yr

U

rs

92 protons 142 neutrons

Gamma rays are emitted during beta decay. They are pure energy on the electromagnetic spectrum that includes light and X-rays. They have no mass or charge but have high energy and can travel much farther than α or β particles.

s

226

Ra 1, 6

00

Half-lives

Each decay along the chain occurs at a unique rate. The time it takes for onehalf of a parent isotope to decay to a daughter isotope is called a half-life.

Half-lives vary from less than a second to billions of years.

Parent and daughter isotopes are often different elements with different physical and chemical properties.

214 Thorium-230 is a metal, but radon-226 is a gas, for example. Th-234 adheres readily to particles in the ocean, while Pa-234 is not as chemically “sticky” and remains in seawater for centuries. All these radioisotopes occur naturally in rocks and water.

yr

s

222 3.

Elemental and chemical changes

218

8d

ay

Rn

Alpha particles have two protons and two neutrons and a +2 charge.

They are 2,000 times larger than β particles and travel relatively slowly and lose energy fast in air. They can’t penetrate clothing, skin, or even paper, but they can be ingested or inhaled.

s

Po Radiation and health

Pb 214

214

Bi

Po 210

210

Pb

Bi 210

Po

End of the chain

occurs when polonium-210 decays into lead (Pb-206) —a stable, non-radioactive metal.

Radioisotopes can emit three kinds of ionizing radiation from their nuclei:

Beta particles are released when a neutron in nuclei turns into a proton, or vice versa. They are charged electrons or positrons that have high speed and energy and can travel far into the body.

in

Th 80

Different types of radioactive decay

206

Pb

When ionizing radiation strikes tissue, cells, and DNA, it can break chemical bonds and otherwise damage cellular machinery.

Depending on a variety of factors, health impacts can occur immediately, such as burns, or over longer terms, such as cancer. All three types of radiation can cause damage, but the larger particles, if inhaled or ingested, can cause the most damage to living tissue. (See Page 20.)

Illustration: Eric S. Taylor/WHOI

Woods Hole Oceanographic Institution

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How Is Fukushima’s Fallout Photos by Ken Kostel/WHOI

By David Pacchioli

Marine Life

T

he Fukushima nuclear disaster delivered an unprecedented amount of radioactivity into the sea over a relatively brief time. How did that pulse of cesium and other radioisotopes make its way through the marine food chain?

Scott Fowler, who helped pioneer marine radioecology for more than 30 years at the International Atomic Energy Agency’s Marine Environment Laboratories, offered a primer on the subject at the Fukushima and the Ocean Conference in Tokyo in November 2012.

The food chain starts with marine phytoplankton—microscopic plants that account for as much photosynthesis as plants on land. These organisms take up radioactive contaminants from the seawater that surrounds them. As the phytoplankton are eaten by larger zooplankton, small fish, and larger animals up the food chain, some of the contaminants end up in fecal pellets or other detrital particles that settle to the seafloor.

These particles accumulate in sediments, and some radioisotopes contained within them may be remobilized back into the overlying waters through microbial and chemical processes.

How much radioactivity gets into marine life depends on a host of factors: How long the organisms are exposed to radioactivity is certainly important, but so too are the sizes and species of the organisms, the radioisotopes involved, the temperature and salinity of the water, how much oxygen is in it, and many other factors such as the life stage of the organisms.

In all this, Fowler said, it’s important to remember the omnipresence of natural background radiation. Polonium-210 and potassium-40 are naturally occurring radioisotopes in the ocean, for example. Potassium-40 is the most abundant radioisotope in the ocean, but polonium-210 accumulates more readily in marine organisms.

“Polonium is responsible for the majority of the radiation dose that fish and other marine organisms receive,” he said.

In an experiment in the early 1980s, Fowler demonstrated vast differences in how much plutonium was absorbed from seawater by marine life across a spectrum of taxonomic groups. Phytoplankton accumulated roughly 10 times as much plutonium as microzooplankton, which took up 100 times more than clams. Octopi and crabs took up about half as much plutonium as clams, but about 100 times more than bottom-dwelling fish.

Another cross-species comparison showed that organisms took up different amounts of radioactivity depending on which particular radioisotopes were out there, he said.

Radioisotopes are also transferred to marine organisms from contaminated sediments—once again in ways that display a complex range of factors, Fowler noted. In one experiment measuring uptake of americium, worms exposed to contaminated sediments took up significantly more of the radioisotope than clams did. But both worms and clams took up much more of the radioisotopes from Pacific sediments, which contain relatively high amounts of silica minerals, than they did from Atlantic sediments, which contain more carbon minerals.

Food is another pathway into marine organisms and “may be in some cases the most important factor in uptake,” Fowler said. Consumed radioisotopes are assimilated internally through the gut, potentially a far more efficient route than if they are absorbed externally from the environment.

Marine invertebrates, such as bottom-dwelling starfish and sea urchins, are particularly proficient at absorbing a wide range of ingested radioisotopes, he said, but fortunately, they lose that incorporated radioactivity over time, via excretion.

From plankton to tuna

Fowler’s longtime colleague, Nicholas Fisher, zeroed in on the isotopes that have had the most impact from Fukushima. Fisher, a marine biogeochemist at Stony Brook University, has spent 35 years studying the fate of metals and radioisotopes in marine organisms, including radioisotopes associated with nuclear waste. He and members of his lab participated in the research cruise led by Woods Hole Oceanographic Institution marine geochemist Ken Buesseler off the coast of Japan in June 2011.

Analyzing plankton and fish sampled on the cruise, they consistently found cesium-134 and cesium-137. Not surprisingly, they found no iodine-131, the isotope which along with cesium had been released in highest quantity from the

damaged Dai-ichi nuclear power plant. Iodine-131, with its half-life of a mere eight days, was undetectable after a couple of months, Fisher explained.

Cesium, of course, is a different story. The ocean and its denizens continue to bear traces of cesium-137 that date from the atmospheric weapons testing during the Cold War era of the 1960s. Cesium-134, while much shorter-lived, will persist for a number of years.

The chemical properties of radioactive cesium are similar to those of non-radioactive cesium and naturally occurring potassium and sodium, which are abundant in seawater. So all these end up in the same tissues, particularly muscle, of fish and other marine organisms. But potassium and sodium are much less abundant in fresh water, so cesium uptake is much higher in freshwater organisms than in sea life.

Fish also excrete cesium fairly efficiently, losing a few percent per day. So if fish are no longer exposed to new contamination sources, the levels in their tissue should decrease fairly quickly.

Of particular concern for top-level consumers is the potential that these radioisotopes will be concentrated as they make their way up the food chain—what ecologists call biomagnification. Fortunately, cesium shows only modest biomagnification in marine food chains—much less than mercury, a toxic metal, or many other harmful organic compounds such the insecticide DDT and polychlorinated biphenyls (PCBs), Fisher said.

On the 2011 cruise, he and his team measured cesium in everything they sampled. “These were primarily zooplankton and some fish,” he reported. As expected, concentrations were higher in organisms sampled closer to shore. Radioactive silver (110m Ag) was also detected in all zooplankton samples. In all cases, however, the amounts of cesium and silver isotopes were much lower than those of naturally occurring potassium-40 in the same samples.

On an expedition in June 2011, biologists collected samples of phytoplankton, zooplankton, shrimp (right) and fish, including the tiny hatchetfish at left, to learn if radioisotopes from Fukushima were accumulating in marine life.

Woods Hole Oceanographic Institution

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Tracking radioisotopes in marine life R adioisotopes released into the atmosphere from the Dai-ichi nuclear power plant fell into the ocean.

W ater used to cool reactors flushed radioisotopes into the sea. icroscopic marine plants M (phytoplankton) take up radioisotopes from seawater around them.

Contaminants move up the food chain from phytoplankton to tiny marine animals (zooplankton), fish larvae, fish, and larger predators. Different radioisotopes are taken up at different rates by different species.

S ome contaminants end up in fecal pellets and other detrital particles that settle to the seafloor and accumulate in sediments.

S ome radioisotopes in sediments may be remobilized into overlying waters and absorbed by bottomdwelling organisms.

Illustration: Eric S. Taylor/WHOI

“The radioactivity of the fish we caught and analyzed would not pose problems for human consumption,” he said.

Which is not, he noted, the same thing as saying that all marine organisms caught in the region are perfectly safe to eat.

Persistently higher-than-normal levels

What’s puzzling to Fisher, Buesseler, and many other scientists is the persistence of these low but significant levels of radioactivity in the ocean. Jota Kanda, an oceanographer at the Tokyo University of Marine Science and Technology, has extensively studied coastal waters off Fukushima and calculated the amount of cesium still present in coastal waters shallower than 200 meters (660 feet) and in sediments on the seafloor.

By his reckoning, what remains is less than three percent of the total discharge, with the rest long since flushed out to the open ocean.

Yet levels of the cesium radioisotopes are still being measured at several tens to hundreds of becquerels per cubic meter in this area, Kanda noted, considerably higher than the levels prior to the Fukushima disaster. More importantly, levels measured in coastal sediments and in some species of fish are higher than those in the surrounding water.

As Kanda sees it, there are three sources responsible for this stubborn presence. One is river runoff—the fallout washed by rainfall into nearby rivers that drain to the sea. He also suggested that a small amount of contaminated water from basement compartments in the reaction unit housing is continuing to leak from the plant itself. But the biggest culprit—the only plausible explanation for the steady levels of radioactive cesium

14 Oceanus Magazine Vol. 50, No. 1, Spring 2013 | www.whoi.edu/oceanus

being measured in fish tissue—is continuous input through a food source. And that, he said, points to sediments.

Kanda has estimated that a total of 95 terabecquerels of cesium (1012 becquerels) is present in coastal sediments. The question, he maintained, is how it got there. It could have drifted down to the seafloor in the fecal pellets of plankton that consumed it at the surface—and in fact, plankton in shallow waters sometimes showed elevated levels of cesium. It could also be arriving with organic bits and pieces carried along by river water. It could have adhered to clay particles that came in contact with contaminated water; such radioactive cesium is tightly bound to clay particles and may not be easily transferred to marine life.

Sediment is complex stuff, he explained. Viewed up close, a single grain of what looks like sand is likely a mélange of mineral, organic matter, and pore water—the liquid trapped in the tiny gaps between particles. How contaminants are taken into these agglomerations is not well understood. Echoing Scott Fowler, Kanda noted that the composition and properties of sediments can vary dramatically.

Solving the mystery of the ongoing radioactivity will require a thorough analysis of the seafloor off Fukushima’s coast, he stressed. “Local communities are concerned. They want to know ‘When can we resume fishing?’ We scientists will have to answer this question.”

The key may be how long cesium stays put and the pathways for its uptake into the food chain. Given the 30-year halflife of cesium-137, the sediments could be a possible source of contamination in the food chain for decades to come.

Tale of the Tuna

U

nderstanding the movement of Fukushima-derived radioactivity through marine ecosystems may come down to getting a better handle on the tiniest of creatures— the microscopic plankton that take up so much volume in the sea. But one species that has become emblematic of the disaster is a shimmering giant: the Pacific bluefin tuna.

Increasingly overfished, Pacific bluefins are among the most prized table fish in the world. A single 500-pound specimen recently fetched $1.76 million in a Tokyo auction. Beyond their allure as high-end sushi material, however, they are amazing migratory animals. Spawned in the waters off Japan and the Philippines, these fish as juveniles swim the entire 6,000-mile breadth of the Pacific—a four-month journey—to fatten up in food-rich waters off California. Years later, larger and sexually mature adults undertake a return crossing to spawn.

As respective experts on radioisotope uptake in marine life and tuna migration patterns, Nicholas Fisher of Stony Brook University and Daniel Madigan of Stanford’s Hopkins Marine Station knew that young bluefins caught off California during the summer of 2011 likely would have spent their early days in contaminated waters off Fukushima. Would these fish act as “biological vectors” transporting radioisotopes between distant shores?

To find out, Fisher and Madigan obtained tissue samples from tuna caught by sport fishermen off San Diego in August 2011, and analyzed them in Fisher’s lab. “Every single bluefin we tested—15 out of 15—had both cesium-134 and cesium-137”—telltale evidence of contamination from the damaged Dai-ichi nuclear power plant, Fisher said. “We were quite surprised to see that.”

The radiation levels they measured were “very, very low,” Fisher stressed. In bluefin tuna caught off San Diego, the total radioactive cesium levels were 10 becquerels, only three percent above radiation levels from naturally occurring potassium-40, and far below safe-consumption levels set by the United States and Japanese governments.

Estimating that the migrating tuna would have lost two percent of any absorbed cesium per day as they crossed—but also would have picked up traces of Cold War-era cesium-137 during their journey—Fisher and his colleagues back-calculat-

ed that when the fish left Japanese waters, the concentrations in them were likely to be 15 times higher, about 150 becquerels per kilogram.

Fisher and Madigan ruled out the possibility that the cesium they measured had been carried on ocean currents or through the atmosphere by also sampling yellowfin tuna, which reside off California but do not migrate across the Pacific Ocean. They found no cesium-134 in these fish, and only background levels of cesium-137.

Fisher and Madigan published their results in late May of 2012, and the response was titanic. “Seven hundred U.S. newspapers, and 400 elsewhere, carried this story,” Fisher recalled, “often on the front page.” He submitted to countless interviews and made several television appearances to try to explain his findings.

“People were genuinely terrified of radioactivity,” he said, “and yet few people could even define it.” To address the anxiety, Fisher and French colleagues calculated dosages, comparing the radiation a person would ingest from eating these bluefin tuna (0.000008 millsieverts) to that received from eating a banana, with its natural potassium (0.0001 mSv), getting a dental X-ray (0.005 mSv), or taking a transcontinental flight (0.04 mSv). He would be more concerned about the health impacts of mercury in these fish, he said, than about radiation.

The scientists continue to analyze radioactivity in bluefins, and Madigan, Fisher, and Zofia Baumann, also in Fisher’s group, recently reported that bluefins caught off San Diego in 2012 had less than half the radioactive cesium of the 2011 tuna, indicating that radioactive cesium concentrations in tissues were indeed declining.

But to Fisher, the real importance so far of these findings is that the presence of Fukushima radioisotopes could be used as unequivocal tracers of migratory patterns of bluefin tuna and possibly other large migratory animals such as sharks, seabirds, and loggerhead turtles. And understanding the timing and routes of migration patterns can help manage fisheries and devise more effective conservation strategies for threatened species.

—David Pacchioli

Fukushima radioisotopes can track the routes and rates of migratory species.

Juvenile bluefin tuna born in 2011 fed in Japanese waters contaminated with cesium-134 from the Dai-ichi nuclear plant and then migrated across the Pacific to feed off the California coast.

Data from Madigan, Baumann and Fisher

Bluefin tuna

Bluefin tuna born before the Fukushima disaster did not have elevated levels of cesium-134, but those caught in August 2011 did.

Yellowfin tuna, which do not migrate and feed near Japan, did not contain cesium-134.

Yellowfin tuna

Seafood Safety and Policy

What’s safe to eat? How can we know?

By David Pacchioli

Yomiuri Shimbun via AP Images

I

2012, experts drawn from various fields examined n Japan, a nation that eats prodigious amounts of the issues surrounding seafood safety. Their spirited seafood, one question sits high on the list of pubconversation ranged well beyond the science. lic concerns: Is seafood caught after the Fukushima nuclear catastrophe safe for human consumption?

In the wake of the disaster, coastal fisheries Proof and perception in Fukushima and all neighboring precincts were Koji Hasebe, a journalist for the Yomiuri Shimquickly closed. Within two weeks, the Japanese bun daily newspaper, described a public mood government began monitoring radioactivity in fish, crystallized in the parents of young children. shellfish, and edible seaweeds. More than a year Fearing internal radiation exposure, parents relater, not because of new scientific findings or any fused to buy milk and produce from Fukushima changes in offshore conditions, but in an attempt to and nearby areas, and instead sought out foodfurther reassure consumers, the government lowstuffs from the west of Japan. “They want to know ered the acceptable limit for radiation in fish from why they must eat contaminated food,” Hasebe 500 becquerels per kilogram—already among the said. He called for improved labeling of seafood strictest standards in the world—to 100 Bq. in the market to provide consumers with precise Last fall, Ken Buesseler, a marine geochemist at information about where fish are caught and their Woods Hole Oceanographic Institution, combed measured levels of contamination. through a year’s worth of data released by the JapaKazuo Sakai, a radiation biophysicist with Janese fisheries agency. His analysis, published Oct. pan’s National Institute of Radiological Sciences, 26, 2012, in the journal spoke of efforts to monitor Science, showed that the radiation intake through “vast majority” of fish bedaily diet. In one study by ing caught off Fukushima the consumer group Coopand surrounding areas had Fukushima, he reported, radiation levels below the 100 Fukushima housetightened safe-consumpholds prepared an extra tion limit. Among bottomportion of their meals to dwelling species, however, be analyzed for radioac40 percent came in over tivity. The results showed that limit. Most important, measurable amounts of celevels of radiation in the sium in only three houseocean and in seafood did holds, and in all cases not appear to be declining showed that naturally ocin the 12 months following curring radiation, in the the accident. form of potassium-40, was To Buesseler and othfar more prevalent. ers, this persistence is A third panelist, Mitstrong evidence of a consuyoshi Urashima, a petinuing source of radiation diatric oncologist at the —Deborah Oughton leaking into the environJikei University School ment. Fish naturally lose of Medicine, served as an cesium quite quickly, adviser to the citizens of about 3 percent per day, if they are not re-exposed Kouri town, adjacent to Fukushima city. Although to some additional cesium source. At the same thousands of people were evacuated from homes time, Buesseler acknowledged, the remaining conclose to the disaster site, Urashima said, these famicentrations of radionuclides in fish are generally lies remain within the range of airborne fallout, and quite low—lower than limits in force in the United “many are still living with a relatively high dose of States, and lower than the amount of radiation nat- radiation exposure.” urally present in seawater.

In 2011, he recommended the removal of conStill, public anxiety in Japan remains high. taminated topsoil from Kouri town schoolyards, With the exception of a few unaffected species a step that he said has reduced surface radiation such as whelk and octopus, fisheries remain closed to 10 percent of pre-excavation levels. He has also off Fukushima prefecture. And disturbing outlimeasured exposure levels in children and pregnant ers—individual fish with exceedingly high levels of women. Ninety-nine percent of those tested, he radiation—continue to turn up. At the Fukushima said, received less than 2.4 millisieverts per year, and the Ocean conference in Tokyo in November a dose equivalent to what most people around the world receive from natural radiation in the environment. “So, basically they are OK,” Urashima said.

The first trial sale of octopus caught off Fukushima began in “But I worry about their fear.”

June 2012, 15 months after the Dai-ichi nuclear plant explosion.

“Public acceptance with regard to these issues comes down to more than becquerels and sieverts.”

Woods Hole Oceanographic Institution

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To further reassure citizens, Urashima urged the town to buy a whole-body radiation counter and similar machines for testing food and water. “Uncertainty is a key factor in the fear of people,” he said. “If they can use the machine to measure their own internal exposure, this may relieve their doubts. If you can measure all the food that’s in the market and show that it’s under 100 becquerels per kilogram, this is very important.”

Cultural considerations

Ironically, some suggested, the Japanese government’s decision to lower acceptable radiation limits in fish may have actually heightened consumer fears instead of dampening them.

Deborah Oughton, an environmental chemist and ethicist at the Norwegian University of Life Sciences, related that the Norwegian government, when faced with high radioisotope concentrations in reindeer meat as a result of Chernobyl, decided to raise acceptable limits from 600 to 6,000 becquerels per kilogram. The move was made, she explained, to protect the livelihood of the minority Sami population that depends on reindeer herding for its survival.

Weighed into the judgment, she added, was the issue of dose: The hazard involves not only how high the levels are in meat, but how much you eat—and Norwegians rarely eat rein-

deer meat more than once or twice a year. The decision had no impact on sales of reindeer meat.

The larger point, Oughton said, “is that public acceptance with regard to these issues comes down to more than becquerels and sieverts. It is a very complex issue.” And nowhere more complex than in Japan. Alexis Dudden of the University of Connecticut offered a historian’s perspective when she suggested that “both at the local level and the national level, some discussion needs to take into consideration Japan’s particular history with radiation.”

For now, Japanese officials continue to keep fisheries off Fukushima closed, and they monitor seafood closely up and down the coast for cesium and other radioisotopes.

“The good news is in that several species, radioisotope levels are slowly decreasing,” Buesseler said. “The bad news is that especially for the bottom-dwelling fish near Fukushima, levels remain stubbornly high. In fact, the most contaminated fish to date was caught in January 2013 in the port of the Fukushima Dai-ichi nuclear power plant. No one can predict yet when this will change, as it depends on both the source of cesium from the power plants, the behavior of cesium in the ocean, and whether the seafloor will remain a long-term source of these isotopes for years to come.”

Exposing the Leaks in Ocean Policy The Fukushima disaster is without precedent and will have unprecedented impacts on future policies governing the ocean, both Japanese and international.

At the Fukushima and the Ocean conference in Tokyo, Hiroyuki Nakahara, a policy expert at Yokohama National University, presented the domestic side of this equation. Japanese ocean policy, Nakahara explained, is governed by the Basic Act on Ocean Policy of 2007. The act requires a renewable five-year plan covering everything from conservation to economic development of the nation’s ocean resources. The first plan was authorized in April 2008, he said, which means the first update is due in 2013. “Intensive discussions are now under way, and include considerations for both recovery from the disaster and renewable energy development,” he said at the conference in November 2012.

To respond effectively to the Fukushima disaster, Nakahara said, the next five-year plan must first include provisions for collecting, organizing, and making available the mountains of environmental data being gathered by dozens of organizations, both Japanese and foreign. Next, it must include a higher degree of cooperation between local and national governments, academia, and industry, as each of these entities continues to investigate causes and effects of the disaster. Finally, he said, the revised plan must incorporate a program for long-term monitoring of Japan’s seas.

At the same time, the Fukushima accident has revealed some key shortcomings in international law, said Kentaro Nishimoto, who teaches law of the sea at Tohoku University. To illustrate, he used an incident that has brought sharp criticism from Japan’s neighbors: the intentional release of radioactive water into the sea.

18 Oceanus Magazine Vol. 50, No. 1, Spring 2013 | www.whoi.edu/oceanus

On April 4, 2011, some three weeks after the initial disaster, the Tokyo Electric Power Co. (TEPCO), with the Japanese government’s consent, decided to release 10,000 tons of “low-level radioactive water” to make room in its storage facilities for the huge volume of more highly contaminated water that had been used for emergency cooling of the damaged Dai-ichi reactors. “This was a minimal amount of radiation compared to the total discharge,” Nishimoto said, but the release raised a couple of legal issues, one related to the act itself and the other to Japan’s belated notification of its neighbors.

In both cases, Nishimoto said, the relevant international laws proved to be nonbinding. In particular, he noted, the London Convention on marine pollution, although it expressly prohibits ocean dumping of radioactive material, limits these restrictions to vessels at sea. Release of materials from land is not considered dumping.

“When I tell this to people outside the field of international law, the reaction I get is, ‘This is absurd,’ ” Nishimoto acknowledged. “But there is an explanation. States make these agreements, and states are very reluctant to regulate anything going on within their territory. They are much more willing to prohibit dumping on the open sea.”

Under the circumstances, he suggested, a regional agreement would be preferable, since neighbors who share a resource may find it easier to reach consensus. But while the Regional Seas Programme launched by the United Nations in 1974 now includes some binding conventions on land-based pollution, none of them covers the region around Japan.

“This type of marine pollution has not been effectively addressed yet,” Nishimoto said.

Rebuilding the Fishing Fleet—or Not If and when fisheries are reopened, repairing the fishing industry will require restoring public trust, conference panelists agreed. It will also demand massive rebuilding of infrastructure.

Environmental economist Shunsuke Managi of Tohoku University outlined the economic costs of the disaster to Japanese fisheries. But he prefaced his talk by stating that the Japanese fishing industry has been in decline for decades.

Since the mid-1980s, Managi said, overfishing has resulted in steadily decreasing production. At the same time, he said, “there are far too many fishermen,” and the Japanese government continues to subsidize the industry heavily. “Without these subsidies, the industry would not survive.”

This is an important context for the events of March 11, 2011, Managi said. On that day and the days that followed, sturdy construction prevented much earthquake damage inland. But the tsunami’s reach far exceeded expectations. Managi estimated a total economic loss of 5 to 7 percent of the Japanese gross domestic product. He put a figure of 2 trillion yen ($20 billion) on damage to agriculture, forests, and fisheries, with 55 percent of that hit taken by fisheries alone.

Destruction of ports and shipping accounts for most of that monetary loss, he said, but he went on to argue that the figures are misleading, since the ports were overbuilt due to excessive subsidies and should be scaled down drastically. Similarly, he suggested, the surviving fleet, which he estimated at 10 to 50 percent

of the before-disaster fleet, is large enough to sustain production.

The more serious problem, Managi said, is that the region’s aquaculture facilities and fish-processing plants were virtually wiped out. Another pressing issue is constructing housing for displaced workers and their families. Longer term, the retention of young people in the industry is a looming concern.

“The general belief is that without re-establishment of the fisheries, there can be no re-establishment of Tohoku region,” Managi said. To restore what was lost, he estimated, would require 10 years and 3 trillion to 14 trillion yen ($30 billion to $140 billion).

But the industry should not be rebuilt the way it was, he argued. Instead, the government should take the opportunity to create a new, competitive fishing industry by cutting subsidies and setting market quotas. Though he has faced resistance to these ideas from those who want to preserve traditional fishing culture, Managi said, he believes that to survive, the industry must adapt. The continuing economic impact of radioactive contamination will be something on the order of 100 billion to 200 billion yen ($1 billion to $2 billion) annually, but he insisted that this impact pales before the cost of inefficiencies that crippled the industry long before Fukushima.

Large fishing boats are washed ashore in Kesennuma, Miyagi Prefecture, northeastern Japan, after the 2011 Tohoku earthquake and tsunami.

(AP Photo/Yomiuri Shimbun, Kaname Muto)

Health Risks

How Can We Assess the Impacts of Radiation Exposures?

By David Pacchioli

T

he ability to gauge radiation at vanishingly low concentrations gives scientists a powerful tool for understanding ocean processes. “We can measure down to less than 1 becquerel”—one radioactive decay event per second, said Ken Buesseler, a marine chemist at Woods Hole Oceanographic Institution. “But just because we can measure it doesn’t mean it’s necessarily harmful to human health.”

At what point, then, is radiation exposure harmful to humans? And what are the likely health effects of the exposures incurred from Fukushima?

Buesseler and colleagues saw plenty of debris from the tsunami floating in the ocean on a research expedition off the Japanese coast in June 2011 (see Page 6), and they continuously monitored radiation levels to ensure that they were not in harm’s way. Measuring seawater samples later in their labs, they showed that the levels of the radioisotope cesium-137 offshore were lower than acceptable levels in drinking water in the United States, yet still more than 1,000 times higher than existed prior to the Fukushima nuclear disaster. And though traces of Fukushima radiation will eventually show up all the way across the Pacific, they will be just that: traces—not enough to affect human health directly.

There is, however, more concern about the Fukushima radioisotopes that end up in fish and seaweed—mainstays of the Japanese diet. “Here we’re talking about accumulation in something you’re going to eat internally versus being exposed to externally,” Buesseler said at the Fukushima and the Ocean conference in Tokyo in November 2012 (see Page 12).

Monitoring of cesium in fish taken from affected areas continues to show an unexplained persistence of higher-than-pre-disaster levels, and the occasional anomalies of individual fish caught near the power plant that register sky-high numbers. Both are indications that more study is needed, and that fish from the Fukushima region can’t yet be pronounced safe to eat. To date, fisheries remain closed in those areas (see Page 16).

The larger health worries are those to be faced on land. As Buesseler explained, “The difference is, on land, once the radiation falls, it stays put, taken up by soils and plants. So you have a long-term source and higher direct exposure to people that doesn’t exist in the ocean, where the radiation is diluted.”

Fortuitous winds

Fortunately, because of prevailing weather conditions at the time of the accident, 80 percent of the radiation released from the doomed Fukushima Dai-ichi nuclear power plant reactors fell on the ocean. That and evacuation of areas affected on land kept acute human exposures limited.

Still, shifting winds and rain a few days after the meltdowns resulted in patchy hot spots of fallout over land.

The highest exposures, not surprisingly, were suffered by workers inside the plant. Over the days of full-bore chaos when emergency crews

20 Oceanus Magazine Vol. 50, No. 1, Spring 2013 | www.whoi.edu/oceanus

raced to limit the scope of the disaster, 167 workers received a radiation dose of more than 100 millisieverts, reported the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). One hundred millisieverts is the level above which experts have demonstrated measurable increases in cancer risks. There is still debate about risks for people exposed to lower doses, because these risks are lower and harder to detect.

For an additional 20,000 Tokyo Electric Power Co. workers, and for the roughly 150,000 Japanese citizens living in the fallout zone, exposures were lower. According to the World Health Organization, most of those residents received doses between 2 and 10 millisieverts. In Namie town and Iitate village, two nearby communities where evacuation was delayed, residents received 10 to 50 millisieverts. In one troubling exception, several news reports cited Japanese officials saying that 1-yearolds in Namie town may have been exposed to 100 to 200 millisieverts of radioactive iodine-131.

This radioisotope, with a short-lived half-life of about eight days, may pose the most serious health threat from Fukushima radiation. James Seward, medical director at Lawrence Livermore National Laboratory in California, told conference attendees that different radioisotopes are taken up differently in the human body, and they target different organs. Iodine gathers in the thyroid, and in high enough doses, its presence causes an increased risk of thyroid cancer, particularly in children.

Thyroid cancer has been the single largest health impact of the Chernobyl nuclear disaster, with 6,000 cases identified by 2005, according to an UNSCEAR report. Fortunately, this cancer is usually treatable and results in few fatalities.

As Seward hastened to add, the average exposures in Chernobyl were much higher than those experienced at Fukushima. Government data collected from 1,080 children in Iwate and other nearby prefectures shows that none received a thyroid dose higher than 35 millisieverts. “There is certainly some risk of thyroid cancer in children in this population,” Seward said. “But that risk is very low overall and may be difficult to measure with epidemiologic techniques.”

The low-dose question

But concerns remain about lingering exposures to cesium radioisotopes, for example. Mitsuyoshi Urashima, a pediatric oncologist at Jikei University School of Medicine, has tested pregnant women and children in Kouri town, adjacent to Fukushima City, and found that one in 100 has received a dose higher than worldwide background radioactivity levels. The anxiety is a reflection, at least in part, of prevailing uncertainty about the effects of low-level exposures.

Seward, a practicing physician with a specialty in occupational medicine and experience treating

The Danger is in the Dose 10,000

10,000 millisieverts (mSv) Short-term exposure is fatal within a few weeks

1,000 mSv Short-term exposure causes temporary radiation sickness and fatal cancer in estimated 5 percent of people exposed

1,000

250 mSv Official allowable shortterm dose for workers controlling the 2011 Fukushima accident

100

100 mSv the level above which experts have demonstrated measurable increases in cancer risks

10

20 mSV maximum limit for European Union airline crews. Crews flying 600 to 800 hours are exposed to 2 to 5 mSv of radiation.

1

mSv

People are constantly exposed to radiation, willingly or inescapably, from a variety of manmade and natural sources.

The risk of harm from radiation depends on both the dose (how much radiation you absorb) and the dose rate (the time you are exposed to a dose). A dose of 1,000 millisieverts (mSv) in an hour is far more damaging than the same dose over a year. But daily low-dose exposure also can add up to cause damage.

6 mSv annual radiation from natural cosmic radiation from space at higher altitudes with thinner atmosphere

2 mSv annual radiation from natural cosmic radiation from space at sea level

0.005 mSv annual exposure from residual radiation from atmospheric nuclear weapons testing.

(It was 0.15 mSV in 1963 at the height of weapons testing.)

2 to 4 mSv annual radiation from natural radioactive elements such as radon in rocks (depends on regional soil types and building materials)

0.0001 mSv eating one banana, one airport security scan

A gray, a unit named for the pioneering British radiobiologist Louis Harold Gray, is the amount of energy absorbed per mass unit of tissue. To account for differing biological effects of different ionizing radiation, grays are converted to an equivalent dose in sieverts, named for Swedish physicist Rolf Maximilian Sievert.

0.15 mSv for dental X-rays

0.04 mSv one transcontinental airplane flight (at high altitudes where thinner atmosphere provides less shielding from natural cosmic radiation from space)

10 mSv full-body CT scan Illustrations by Paul Oberlander

acute radiation poisoning, tackled what is known as the lowdose question. He began by laying out some of the basics.

Humans around the globe are constantly exposed to small amounts of radiation, but at low levels that don’t appear to produce known health effects, Seward said. This background radiation exposure averages 3 millisieverts per year and comes from natural and artificial sources. The former includes cosmic radiation (high-energy particles originating outside Earth’s solar system) and radon in rocks; the latter includes medical X-rays, CT scans, and even travel in airplanes at high altitudes, where the thinner atmosphere offers less protection against incoming cosmic radiation. For the same reason, exposure is higher for people living at high altitudes and can range up to 10 millisieverts a year.

Radiation can enter the body via internal and external pathways. It can penetrate the body like X-rays, and it can be inhaled from the air, absorbed through the skin, and ingested with food and drink. Once within the body’s cells, these unstable radioisotopes act to damage DNA, either directly, by striking DNA or other cellular molecules themselves, or indirectly, by creating free radicals—highly reactive molecules that can cause the damage.

As long as the dose is limited, the body has repair mechanisms to keep this damage in check. When that system is overwhelmed, however, radiation can create two types of effects. The first, called deterministic effects, occurs to any individual who receives high-dose exposures. They produce Woods Hole Oceanographic Institution

21

Random effects

The other type of effects are called stochastic or random, and most significantly, they include cancer. A lot of what we know about stochastic effects in humans, Seward said, comes from long-term studies of the survivors of the atomic bombs dropped on Hiroshima and Nagasaki. These studies show that above doses of 100 millisieverts, the risk of getting cancer—but not the severity of the disease—rises in a straight line with exposure.

At 100 millisieverts, the increased risk of cancers is very small: around 0.5 percent, he noted. As he explained it, the average Japanese male, throughout his lifetime, has a 26 percent chance of developing a fatal cancer from any cause; the average female, 16 percent. With the addition of a 100-millisievert radiation exposure, that risk rises to about 26.5 and 16.5 percent, respectively. For individuals exposed as children, the numbers are slightly higher.

Below that 100-millisievert level, however, the picture becomes much less clear. “There is only limited evidence to show a dose-related effect,” Seward said. Safety standards established for these low-level exposures—for power plant workers, for instance, and radiation technicians—depend therefore on something called the linear no-threshold model, which, as Seward noted, is simply extrapolated from the impacts seen at higher doses. In essence, the model conservatively holds that any dose of radiation increases cancer risk: There is no bottom threshold.

The hitch is that scientists by no means agree on the validity of this theory. Some say low-dose exposures below some threshold are harmless. Some even claim they have a beneficial effect

on DNA repair (a phenomenon known as hormesis). Others argue that low-dose risks may be higher than currently predicted.

“The key point,” Seward said, “is that the linear no-threshold model is best applied for setting safety standards.” It errs on what many scientists consider to be the safe side. It is unlikely to be an accurate predictor of the numbers of cancers resulting from exposures when very low doses are involved.

The challenge, Seward said, is that in a population where radiation exposures are very low, it may be difficult to detect a significant change in cancer rates and attribute that with certainty to the Fukushima releases.

Confounding factors

In July 2012, uncertainties notwithstanding, Stanford University scientists John Ten Hoeve and Mark Jacobson published a prediction of the total cancer casualties that will eventually accrue from the Fukushima nuclear disaster: 130 deaths and 180 additional cancers, they say. Ten Hoeve and Jacobson pointed out that, while evacuation of the affected precincts was necessary under the circumstances, more individuals may have died in the process of that evacuation than are expected to die from the long-term effects of radiation exposure.

The study, published in the journal Energy and Environmental Studies, was widely reported in Japan and elsewhere. As Seward noted, however, its results encompass a vast range of possibilities: between 15 and 1,100 fatalities and between 24 and 1,800 additional cancers.

“To most people, there’s a big difference between 39 cancers and 2,900,” wrote Geoff Brumfiel, a journalist who covered the Fukushima crisis for the journal Nature and who attended the conference. “The problem is that these types of estimate depend on models and assumptions.”

“It’s a challenging problem,” said Dale Preston, a biostatistician at Hirosoft International in Eureka, Calif., who specializes in radiation health effects. “One of the main reasons is that radiation-affected cases are indistinguishable from other

Radiation Effects on Human Tissue Different types of ionizing radiation have different potential to cause cellular damage, depending on their size, energy, and access.

Alpha particles Ionizing Radiation

are are relatively relatively large large and and slow. slow. They They can’t can’t penetrate penetrate skin, skin, but but ifif inhaled haled oror ingested, ingested, their their size size can can cause cause more more damage damage than than other other forms forms of of radiation. radiation.

Beta particles

have particlesand andcan canpenetrate penetrateskin, skin,but buttheir their have 1/2000th 1/2000th the the mass mass of of α α particles smaller smaller size size reduces reduces damage damage potential. potential.

Gamma rays

have have high high energy energy but but no no mass mass or or charge. charge. They They can can pass pass through through tiny tiny spaces spaces between between cells cells without without causing causing disruption, disruption, but but they they can can cause cause damage damage ifif they they hit hit cellular cellular structures. structures.

22 Oceanus Magazine Vol. 50, No. 1, Spring 2013 | www.whoi.edu/oceanus

Certain body tissues (e.g. bone marrow) are more sensitive to radiation than others. Certain tissues are more likely to absorb certain radioisotopes (e.g. the thyroid and iodine-131).

Once inside the body’s cells, ionizing radiation focuses high energy on small but crucial areas in proteins, DNA, or other cellular components—“a bit like a karate master focusing energy to break a brick,” according to a U.S. Department of Energy report. It damages cellular machinery in two ways.

di re

health problems that include skin burns, eye cataracts, and, in pregnant women, harm to the developing fetus. Thankfully, Seward said, “this type of effect has not turned out to be a significant issue around Fukushima, and it does not appear that even the more highly exposed nuclear plant workers experienced these health problems.”

ct

in di

ly

r ec tl

y

cases. It requires very well-designed epidemiological studies to estimate the number of affected cases, and in the case of low doses, it requires very large studies that go on for a long period of time.”

The reality is that the estimated increases in fatalities and cancers are small compared with the overall cancer mortality in Japan and elsewhere, which affects 15 to 25 percent of the total population.

“We do know that the magnitude of effect depends on the dose,” Preston continued. “We also know that the effects, if any, of low to moderate doses appear to be small.” But sifting out those effects requires accounting for how they will vary— not just with dose rate but with factors such as time since exposure, age at exposure, sex, and ethnicity, not to mention interactions with other risk factors like smoking. Despite these challenges, he argued, some data that are relevant to Fukushima do exist.

He pointed first to the A-bomb survivors. Among 93,000 who were exposed to radiation at Hiroshima and Nagasaki, he said, 25 percent received doses within the low-dose range. A second long-term study involves some 30,000 villagers in the Techa River valley of southern Russia, whose exposure was quite different: repeated environmental releases from a plutonium production facility during the 1950s. Both studies, Preston said, show slightly increased rates of leukemia and other cancers associated with exposures below 100 millisieverts.

Long-term health impact studies needed

In February 2013, the World Health Organization issued a health risk assessment report on the Fukushima nuclear accident conducted by more than two dozen scientists in various fields. It estimated somewhat elevated risk for cancers in certain age and sex groups in the most contaminated areas—for example, for girls exposed as infants to radioactivity in the

most affected regions of Fukushima Prefecture—but no observable increase in cancer rates in wider Japanese populations and no discernible health risks outside Japan.

But, the report concluded, “This health risk assessment is based on the current state of scientific knowledge. … Because scientific understanding of radiation effects, particularly at low doses, may increase in the future, it is possible that further investigation may change our understanding of the risks of this radiation accident.”

Questions and concerns also linger about exposures from short-lived radioactive gases released from the plant, such as the noble gas xenon-133, which has a half-life of five days.

Several speakers raised this issue at a conference on the medical and ecological consequences of Fukushima at the New York Academy of Medicine in March 2013, said Buesseler, who attended that conference on the two-year anniversary of the disaster.

Preston and Seward agreed on the importance of a longterm study of the Fukushima population—even “if the power to detect effects may be limited,” Preston said. “If the study finds nothing, that in itself will be reassuring to the public.”

In July the Fukushima Medical University launched an ambitious survey intended to establish individual radiation exposures by pinpointing people’s exact whereabouts during the crisis, the amount of time they spent outdoors, and everything they ate and drank. The study will provide ongoing thyroid exams for all of Fukushima prefecture’s children, and checkups for pregnant women and evacuees. It is expected to continue for at least 30 years.

Preston and Seward both suggested including another component to long-term health studies on Fukushima: a careful analysis of the disaster’s psychological impacts. In the end, they said, the stress of living with the uncertainty about exposure to low-dose radiation, which science cannot yet unravel, may well turn out to be the largest and longest-lived health effect of all.

High-level exposure causes acute effects:

Radiation strikes cellular components.

If radiation doses are limited, the body has mechanisms to repair damage, but higher doses can overwhelm the repair systems.

OH-

radiation sickness, skin burns, eye cataracts, and harm to developing fetuses in pregnant women.

Lower doses cause stochastic effects: gradually increasing the risk of damage with increasing doses.

Increased cancer risks are measurable in people exposed to doses over 100 millisieverts.

Radiation creates free radicals— highly reactive atoms or molecules that “steal” electrons from stable molecules and disrupt their functioning.

Below 100 millisieverts, changes in cancer risks are difficult to measure.

Illustration: Eric S. Taylor/WHOI

Woods Hole Oceanographic Institution

23

Communicating Disaster How Did Government, Scientists, and the Media Perform in the Crisis?

By David Pacchioli

Fukushima Central Television

F

or most of Japan and the rest of the world, the first clear sign of trouble at the Fukushima Dai-ichi nuclear power plant was a breaking news video aired the day after the tsunami in March 2011. Captured live by Fukushima Central Television (FCT) and broadcast four minutes later, the video showed a thick white cloud emerging over the plant—what turned out to be the explosion of the Unit 1 reactor (above). At the time, however, the only facts that were known came across in the newsreader’s urgent voiceover. It looked like smoke, she said, but it might be water vapor. It appeared to be drifting north, over the ocean.

Yuji Terashima, the FCT managing director responsible for airing that footage, described those desperate days for attendees of the Fukushima and the Ocean conference in Tokyo in November 2012. Terashima was part of a panel of Japanese and American journalists who examined efforts to communicate during and after the disaster.

“As a local media outlet,” he recalled, “it is our primary role to immediately report events occurring around us, especially in the event of a disaster. However, we didn’t know the substance of what we had seen. We were forced to report events as we saw them.”

Martin Fackler, Tokyo bureau chief for The New York Times and another panelist, was similarly in the dark. “That’s how I would characterize the first ten days,” Fackler said. “The government was telling us nothing. TEPCO [Tokyo Electric Power Co., operator of the plant] was telling us nothing. We had very little input from the scientific community in Japan. Here we are trying to figure this out, and we had first one, then two, then three explosions.”

Fackler had to talk with scientists overseas to learn that what he had witnessed were likely hydrogen explosions, which probably meant partial meltdowns of the affected reactors. “But when we reported this, we had so much criticism from the Japanese side for using the word ‘meltdown,’ ” he said. “There was this amazing denial.”

Only FCT’s camera survived a blackout and captured the explosions. And the footage was aired exclusively on that network in Japan. The Japanese government had declared a state of emergency, and confusion and fear were rampant.

“Some people commented that our decision to broadcast pictures of the explosion was brave,” Terashima recounted. “My own belief is that it is irresponsible to hesitate to disclose critical information of this nature and to justify that by stating that it could cause panic.” In the event, many Japanese citizens simply turned to YouTube, where clips of the explosions taken from foreign news broadcasts were abundant.

“As a result of this broadcast, the public realized the true seriousness of the crisis,” Terashima said, “and many decided to evacuate.” And a pervasive attitude of suspicion and mistrust of the authorities began to take hold.

24 Oceanus Magazine Vol. 50, No. 1, Spring 2013 | www.whoi.edu/oceanus

Days of confusion

Geoff Brumfiel, who reported on the crisis for the journal Nature, offered conference attendees a somewhat different perspective. “In London, where I was,” Brumfiel said, “I was surprised at how quickly the information was coming and how much there was. TEPCO was providing preliminary radiation numbers within 24 hours of the accident, and real-time updates on conditions at the reactor.”

The real problem, Brumfiel suggested, was not a lack of information, but a lack of communication—a distinction that would grow clearer during the second phase of the crisis. After a week and a half with little official word, Fackler said, “there was an information dump. I guess the government had had enough criticism. They just threw crates and crates of numbers at us with no explanation.”

At that point, Brumfiel said, with few reporters possessing any expertise in the radiation physics, “it became very hard for the media to understand what the risk actually was. And the government, meanwhile, was trying to wiggle out of the numbers they were reading.

Even as the doses were going way above established safety levels, they were saying, ‘Everything’s fine, there’s no risk.’ ” To Terashima, the futile attempts by government officials to forestall panic were themselves a form of crippling fear.

Indeed, this so-called “elite panic” likely contributed to a widely reported debacle

regarding the government’s System for the Prediction of Environmental Emergency Dose Information, known as SPEEDI. This sophisticated computer forecasting system began generating predictions of the spread of airborne radioactivity almost immediately after the disaster, but the first public release of this information was delayed for almost two weeks.

Lacking this or any other guidance, residents of at least one evacuating community, instead of moving away to safety, headed straight into the path of the fallout.

Fackler, reporting for the Times, wrote that “Japan’s political leaders at first did not know about the [SPEEDI] system and later played down the data, apparently fearful of having to significantly enlarge the evacuation zone—and acknowledge the accident’s severity.” Whatever the motives, the withholding of data, critics say, put unsuspecting citizens into harm’s way, and the result was a further erosion of public trust.

There were other, similarly fateful decisions. Brumfiel noted the rush by some affected prefectures, in the days following the disaster, to pronounce their local rice and fish safe to eat—and subsequent findings of contamination in those same foodstuffs. Even more damaging, he said, was the government’s unexplained—and seemingly arbitrary—raising of safe radiation-exposure levels for schoolchildren, from 1 millisievert to 20 millisieverts per year (see Page 20).

Combined with nagging uncertainty about the effects of low-level radiation, these official missteps created frustration and anger in the Japanese public—emotions directed not only at the government, but also at Japanese scientists, many of whom were reluctant to speak publicly.

Any news is good news

Nor did the media come through unscathed. Panelist Masakatsu Ota, a senior editorial writer for the Tokyo-based Kyodo News agency, acknowledged early mistakes by many of his peers, including a lack of preparedness for covering large-scale disaster, an unwillingness to criticize the beleaguered government, and a tendency, when lacking necessary expertise, to parrot the official line.

In the vacuum that resulted, worried citizens turned to other sources for information. Many sought out foreign websites and news services. In other cases, citizen volunteers stepped into the breach.

Toshio Katsukawa is a fisheries management specialist at Mie University who has spent most of his time since March 2011 helping fishermen in some of the many villages destroyed by the tsunami. As a parent worried about what to feed his children, however, Katsukawa began educating himself about radiation health effects, and, after talking with other concerned parents, he decided to share food safety information via the Internet. His blog and Twitter feed became so popular that he was asked to speak to consumer groups, write for a women’s magazine, and eventually to appear on television.

“Japanese scientists hesitated to release information that was uncertain,” he told attendees of the conference in Tokyo. “But almost everything was uncertain after the accident.” Given that most of the radioactive iodine that wound up in the atmosphere was released during the first two days, he said, “there was no time to wait for uncertainty to disappear.”

What he found in his own efforts at communication, Katsukawa added, was that “most people did not demand perfect information. They were OK with uncertainty, as long as things were carefully explained. They just wanted to know.”

Unfortunately, as Katsukawa and others reported, the tendency to withhold information and downplay radiation risk has had lasting consequences across post-disaster Japan. Miguel Quintana, a correspondent for Nuclear Intelligence Weekly who has reported extensively from Fukushima, told conference attendees, “There’s a big disconnect be-

New Center for Marine and Environmental Radioactivity Launched

W

e live in a radioactive world. There are more than 1,500 radioactive isotopes (radionuclides) on Earth. Most originated from the Big Bang and are naturally occurring in rocks, water, and air. Some are human-made products of the nuclear era that were released into the environment by Cold War weapons testing and by accidents, such as Chernobyl and Fukushima.

Radionuclides have widely varying chemical and physical properties. Some have known impacts on human health; others pose risks that are misunderstood and/or overstated. Many have been used as tracers to study environmental processes and enabled revolutionary understanding of the natural world.

In the aftermath of Fukushima—after years of relative complacency—the public and policymakers have renewed concerns about radioactive contamination. There are more than 400 nuclear power plants worldwide, a number that is growing in many countries. In addition, radioactive wastes have piled up without safe storage, nuclear-fueled ships and submarines ply our oceans, and there are concerns about the spread of nuclear weapons and non-nuclear “dirty” bombs. Yet, at the same time, many nuclear scientists and radiochemists trained during the Cold War are retiring.

“There is a need for trained experts to respond when needed, and research from trusted, independent laboratories is essential for building public confidence,” said Ken Buesseler, a marine chemist at Woods Hole Oceanographic Institution. That realization inspired him, immediately after he returned from Tokyo, to begin to establish a new Center for Marine and Environmental Radioactivity (CMER) in partnership with other institutions worldwide.

CMER will provide training for the next generation of radiochemists and support a critical mass of scientific capability. Its mission is to propel scientific breakthroughs and generate valuable knowledge that will inform the public and policymakers about the risks, benefits, and impacts of ionizing radiation in the environment.

www.whoi.edu/CMER Woods Hole Oceanographic Institution

25

tween public perception and the scientific information that’s out there. A lot of people I talk to totally mistrust the information they’re getting.”

The Times’ Fackler concurred. “There are big, big issues that still haven’t been resolved,” he said. “There still is no social consensus. My friends who are Japanese don’t buy seafood from the Pacific—they don’t trust the monitoring, the reassurances. They see a bureaucratic system that favors producers over consumers and has consistently lied to consumers about safety levels.”

Trust and disconnects

Given the level of mistrust, some international attendees said, it should not surprise Japanese scientists that their reassurances fall on deaf ears. Instead of trying to downplay risks, they advised, experts must first acknowledge the depth of public anger. Abel Gonzalez, an adviser of the Argentine Nuclear Regulatory Authority who conducted assessments of the Chernobyl accident for the International Atomic Energy Agency, said that in his experience, trying to minimize concerns is counterproductive. Instead, he argued, “We have to say, ‘You are right to be upset. You are right to be angry.’ ” Seconding this approach was John Stein, director of the U.S. National Oceanic and Atmospheric Administration’s Northwest Fisheries Science Center, who led NOAA’s seafood safety program in the Gulf of Mexico after the Deepwater Horizon oil spill.

“Down on the Gulf Coast, being a federal scientist, I was by definition untrustworthy,” he said. “If there’s one lesson we took from that experience, it’s that communicating the science is an incredibly difficult issue. You very much have to acknowledge what happened. People are very hurt by an event like this. Rebuilding that trust, and rebuilding public and consumer confidence, takes a long time.”

One thing that helped to establish NOAA’s credibility in the Gulf, Stein said, was engaging outside experts to conduct independent tests. Katsukawa agreed. “Scientists from other countries can be a big help,” he said. When the environmental organization Greenpeace measured airborne radiation around Fukushima and their results matched those of the government, he said, the government regained some of its credibility.

What is the role of scientists?

Katsukawa’s volunteer work illustrates an important role for independent scientists within Japan. As Brumfiel noted, “In my reporting, I’ve heard of physicists coming out into the field with their germanium detectors, taking measurements of the soil, working with the local people—and I think there’s a lot of that going on. I think what’s missing is a formal voice for these individuals.” The establishment of some truly independent nongovernmental organizations, or NGOs, in Japan, Katsukawa and Brumfiel both suggested, would be an important step forward.

Another piece of advice was repeated often throughout the symposium: To credibly share expertise on so sensitive a topic as radiation health, it’s important that scientists don’t try to persuade the public simply to take their word. “Hearing a scientist say, ‘Your exposure has been low so you have nothing to worry about’ doesn’t work at all,” is the way Miguel Quintana

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put it. Kazuo Sakai, a radiation biophysicist with Japan’s National Institute of Radiological Sciences, agreed. “Science is not able to convince anybody,” he said. “All we can do is say, ‘Here is your exposure level, and based on past experience, here are the associated effects.’ You must judge for yourself.’ ” Last but not least, the panel stressed, scientists must find ways to work productively with the media, even when doing so involves overcoming an ingrained lack of confidence in journalists’ ability—and desire—to “get it right.” Buesseler, whose extensive media contacts date back to Chernobyl, suggested that the key is finding and engaging journalists who can be trusted not to distort a nuanced message.

For his part, Ota of the Kyodo News acknowledged this natural tension. But after Fukushima, he said, the relationship between scientists and the media is too important not to cultivate. “There are fundamental questions of governance of this country,” he said. “This exchange, this dialogue between media people and specialists, is critical for our future.”

The myth of absolute safety

A day after the Fukushima and the Ocean conference, participants held a meeting open to the general public. At that event, Brumfiel, speaking for the media, summarized his impressions from 18 months of reporting on Fukushima. “The conclusion I come away with,” he said, “is that scientists and the government, faced with communicating this disaster, were very concerned with protecting the public. They didn’t want to cause a panic, they didn’t want to spread fear—but in trying to avoid doing so, they withheld information, and this spread more fear than anything else they probably could have done.

“In a funny sort of way,” he added, the official tendency toward reassurance at all costs reflected a problem that existed well before the accident. “It’s this idea of absolute safety. And I think it’s not just in Japan but everywhere in the world. The nuclear industry wants people to believe that nuclear power is absolutely safe. They work very hard to make that case. I think Fukushima shows the risk of preaching absolute safety. Because when this accident happened, the government had no real policy in place for responding to it.”

His words echoed those of Takashi Onishi, president of the Science Council of Japan, whose remarks had opened the conference. “The myth of absolute safety has dominated the policies of this country and prevented us from applying additional improvements to our nuclear power plants,” he said. “This groundless myth shouldn’t be revived.”

Instead, he said, the science council must take a lead role in promoting a change in mindset, from one of absolute safety to one that recognizes the inevitability of future natural disasters and aims not at preventing or avoiding them, but at anticipating them and reducing their impact. Such a mindset, he said, must incorporate the lessons of past mistakes.

Onishi cited a nationwide opinion survey that showed public confidence in Japan’s scientists dropping sharply after the Fukushima disaster, and rebounding only partially since then.

“We understand as an organization of scientists that we failed to live up to the people’s expectation,” he said. “Without this careful investigation and reflection we cannot fully recover their confidence.”

Fukushima and the Ocean

かつてない放射性汚染物質の 海洋流出から私たちは何を学んだか 第50巻 第1号 2013年春季

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