” TOKYO — In the chaotic, fearful weeks after the Fukushima nuclear crisis began, in March 2011, researchers struggled to measure the radioactive fallout unleashed on the public. Michio Aoyama’s initial findings were more startling than most. As a senior scientist at the Japanese government’s Meteorological Research Institute, he said levels of radioactive cesium 137 in the surface water of the Pacific Ocean could be 10,000 times as high as contamination after Chernobyl, the world’s worst nuclear accident.
Two months later, as Mr. Aoyama prepared to publish his findings in a short, nonpeer-reviewed article for Nature, the director general of the institute called with an unusual demand — that Mr. Aoyama remove his own name from the paper.
“He said there were points he didn’t understand, or want to understand,” the researcher recalled. “I was later told that he did not want to say that Fukushima radioactivity was worse than Chernobyl.” The head of the institute, who has since retired, declined to comment for this article. Mr. Aoyama asked for his name to be removed, he said, and the article was not published.
The pressure he felt is not unusual — only his decision to speak about it. Off the record, university researchers in Japan say that even now, three years after the triple meltdown at the Fukushima Daiichi plant, they feel under pressure to play down the impact of the disaster. Some say they cannot get funds or university support for their work. In several cases, the professors say, they have been obstructed or told to steer clear of data that might cause public “concern.”
“Getting involved in this sort of research is dangerous politically,” said Joji Otaki, a biologist at Japan’s Ryukyu University who has written papers suggesting that radioactivity at Fukushima has triggered inherited deformities in a species of butterfly. His research is paid for through private donations, including crowdfunding, a sign, he said, that the public supports his work. “It’s an exceptional situation,” he said.
The precise health impact of the Fukushima disaster is disputed. The government has defined mandatory evacuation zones around the Daiichi plant as areas where cumulative dose levels might reach 20 millisieverts per year, the typical worldwide limit for nuclear-power-plant workers. The limit recommended by the International Commission on Radiological Protection is one millisievert per year for the public, though some scientists argue that below 100 millisieverts the threat of increased cancers is negligible.
In an effort to lower radiation and persuade about 155,000 people to return home, the government is trying to decontaminate a large area by scraping away millions of tons of radioactive dirt and storing it in temporary dumps. Experts at Japan’s National Institute of Advanced Industrial Science and Technology put the cost of this project at $50 billion — widely considered an underestimate.
The chance to study in this real-life laboratory has drawn a small number of researchers from around the world. Timothy A. Mousseau, a professor of biological sciences at the University of South Carolina who has written widely on Chernobyl, studies the impact of radiation on bird and insect life. He has published papers suggesting abnormalities and defects in some Fukushima species. But he said his three research excursions to Japan had been difficult. … ”