Survey checks radioactive contamination in the Pacific

January 13, 2013


TOKYO--The Great East Japan Earthquake and ensuing tsunami reminded us of the terrible damage the sea is capable of inflicting. But what about the damage caused to the sea by the accident at the Fukushima No. 1 nuclear power plant?

A team of researchers from the United States, Japan and elsewhere has been studying this very question to see how the Pacific Ocean’s waters and marine life have been affected by what has been dubbed “the worst accidental release of radiation to the ocean in history.”

In mid-November last year, the U.S. Woods Hole Oceanographic Institution (WHOI) and the University of Tokyo’s Atmosphere and Ocean Research Institute held a symposium in Tokyo titled “Fukushima and the Ocean.” Over two days, around 90 marine researchers from the United States, Japan and so on gathered to discuss the extent of marine radioactive contamination and how this information should be communicated to the general populace. On the final day, the debate was opened to the public and close to 200 people attended; proof, if any were needed, that these issues are not merely the concern of a few specialist researchers.

The symposium’s roots can be traced back to less than a week after the accident occurred, when Ken Buesseler, senior scientist at WHOI, called on researchers from all over the world to help ascertain radiation levels off the coast of Fukushima and the accident’s impact on marine life. At the beginning of June 2011, a team of around 20 scientists from the United States, Japan and Spain set sail on a two-week field study aboard a ship provided by the University of Hawaii.

The team surveyed an area 30 to 600 kilometers offshore from the nuclear plant. They took samples of seawater from more than 30 locations, from the ocean surface right down to depths of 2,000 meters. The samples were then analyzed by 16 laboratories in seven countries, including Monaco and Slovakia. The Tokyo symposium was held in the wake of this research.

According to Buesseler, when radioactive debris is released into the sea, it usually gets dispersed far and wide by ocean currents before eventually finding its way to the seabed. This survey showed radiation levels spiking in areas where eddies commonly form due to the complicated interplay of the Kuroshio and Oyashio currents.

One of the participants, Jun Nishikawa, assistant professor of the University of Tokyo’s Atmosphere and Ocean Research Institute, says the highest detected cesium-134 and cesium-137 activity was around 3,900 becquerels per cubic meter (bq/m3). This reading was made not in the seas close to the nuclear plant, but in an area of near-shore eddies to the southeast. The research also revealed that concentrations of radioactive cesium isotopes in the surveyed area were 10 to 1,000 times higher than before the accident occurred.

“We still don’t know enough about how cesium isotopes accumulate in the bodies of fish, so further observations will be needed from hereon,” says Buesseler.

Professor Jota Kanda from the Tokyo University of Marine Science and Technology adds that “fish species absorb cesium in different ways. Even in areas with low concentrations of radioactive material, we are still finding some fish types that manifest higher-than-normal concentrations.”

Kanda, who compiled the results of the two-day symposium, says that when flatfish were exposed to cesium-134 during an experiment, “young fish absorbed high levels quickly, whereas mature fish absorbed it more slowly.”

“The Fukushima accident demanded research above and beyond what any one single nation could undertake,” says Buesseler. “Our survey involves research institutions from several countries and is independent from the Japanese government, so I think it will live up to the expectations of the Japanese people too.”


DATE, Fukushima Prefecture--The International Commission on Radiological Protection (ICRP) wields tremendous influence as the body responsible for setting international standards for radiation protection. The French economist Jacques Lochard, 62, and several other key ICRP figures have been participating in a series of public dialogues in Date, Fukushima Prefecture. At the fourth such meeting in November, held to discuss the impact of the nuclear accident on schooling in the region, Lochard exchanged views with local teachers and offered advice on how to treat radiation damage.

The ICRP was invited to attend by the local community, but Lochard says Date’s residents were a little standoffish in their first meeting with the foreign visitors. By the second meeting, though, they had become more relaxed and a fully fledged discussion ensued.

There have been several such dialogues since then.

“Fukushima’s experiences have been shared throughout the world, but when you speak to the locals, they have a strong sense of being treated unfairly. It was quite an eye-opener,” says Lochard. He believes his role is to answer the questions of the local residents while communicating their problems and opinions to the outside world.

Lochard also visited areas afflicted by the Chernobyl nuclear accident in 1986. His aim was to listen to the demands of the local community and ascertain what they needed to return to a normal life. There are many differences between Chernobyl and Fukushima, though.

“In Chernobyl, people were kept totally in the dark about what was going on, whereas there is too much information in the case of Fukushima, so local residents don’t know what to believe,” he explains.

At the same time, Lochard feels there are many similarities too. In both cases, for example, the afflicted communities began to feel a strong sense of abandonment as time passed.

Locals often quiz Lochard about whether they should return to decontaminated homes or move somewhere new instead.

“I can’t really tell them what the best course of action would be,” he says. “What I can do, though, is listen to their worries and continue to engage them in dialogue.”

The ICRP is a network of around international 250 experts involved in research and other work related to radiation. The body is essentially a loose group of scientists without any centralized organization, yet it nonetheless has an important influence on the Japanese government’s radiation policies.


At the end of October, Japan was visited by 11 administrative officers and scientists from Chile, Peru, the Philippines, Turkey, China and Bangladesh, six diverse countries that all share one thing in common with Japan: the omnipresent threat of a mega-earthquake. The trip was part of a training course organized by the Japan International Cooperation Agency (JICA). The trainees visited areas impacted by last year’s disaster, such as Ofunato and Miyako in Iwate Prefecture or Kesennuma in Miyagi Prefecture.

The tour took in embankments breached by the tsunami, for example, and areas designated evacuation spots. The participants listened to the experiences of people who had been swept up in the tsunami or doctors who had helped out with rescue operations. They also visited the Kansai region, scene of the Great Hanshin Earthquake in 1995. All in all, the team spent around two months talking directly to people affected by the disasters or to experts in disaster prevention. Topics on the agenda included how local governments responded directly after the earthquake and how medical treatment was dispensed in the absence of many essential utilities.

“Istanbul lives under the constant threat of a major earthquake striking. We need to think about how to protect the city’s 2.5 million schoolchildren,” said one participant, Istanbul Deputy Governor Harun Kaya, 46. During the trip, he heard how evacuation drills are conducted at Japanese schools. “I want to use such drills as a springboard to spread awareness about disaster prevention among Turkish families.”

Boris Saez, 39, is the man in charge of disaster prevention planning in the central Chilean municipality of Talcahuano. He recalls a conversation with someone who hadn’t fled the tsunami because of a naïve faith in the strength of the levees.

“The message really hit home that even the best anti-disaster facilities can’t keep us safe just by themselves,” he says. When he returns to Chile, Saez says he will push for the continuation of regular disaster drilling.

In 2012 alone, more than 500 people from all over the world have visited disaster-hit areas in Japan as part of JICA’s training programs. Travel and accommodation expenses are covered by JICA out of the Japanese government’s Overseas Development Assistance (ODA) budget. In return, the participants are expected to propose concrete targets for improving anti-disaster planning after they return to their own countries.

“I hope the trainees can learn firsthand about Japan’s disaster prevention technologies and experiences, and then incorporate this knowledge into anti-disaster planning in their own countries,” says a JICA spokesperson.

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Photo: Ken Kostel ©Woods Hole Oceanographic Institution

Photo: Ken Kostel ©Woods Hole Oceanographic Institution

  • Photo: Ken Kostel ©Woods Hole Oceanographic Institution
  • French economist Jacques Lochard (Photo: Mizuho Kajiwara)
  • Trainees visit a disaster-hit area. (Photo provided by JICA)

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