By YUKA HAYASHI
http://online.wsj.com/article/SB10001424052970204879004577108954246383844.html?mod=WSJ_World_LeftCarousel_3
KASHIWA, Japan—The struggle to understand the health consequences of the Fukushima Daiichi nuclear meltdown carries an eerie echo of Japan's past: The nation is still debating who is a victim of the atomic bombs that destroyed Hiroshima and Nagasaki in World War II.
On Wednesday, in the latest in a series of high-profile lawsuits, four of five people who were exposed to radiation from the bombings—but weren't present at the actual blasts—won official recognition as victims. Until recent years, Japan held that only people who experienced the actual blasts at close range were victims, because secondary radiation posed negligible danger.
This debate resonates today because many potential victims of the Fukushima disaster will have received only secondary radiation, for instance from eating tainted food or inhaling dust.
Which is one reason why Takashi Asahina, 79 years old, says he recently brought a megaphone to the train station in Kashiwa—a town on high alert because radiation "hot spots" from Fukushima have been found here, 120 miles away.
As commuters hustled by in a winter shower, Mr. Asahina warned passing mothers to keep children sheltered from the rain and advised anyone who would listen to track their radiation exposure. "Radiation effects won't show up immediately," he said. "Don't take down your guard."
It's a lesson Mr. Asahina says he learned from his own years-long court battle to gain recognition as a Hiroshima victim. He wasn't near the hypocenter, or ground zero, for the blast in August 1945, but went there two days later, putting him in a category known as "early entrants." A cancer survivor, he was recognized as a victim only in 2008.
"I think the court cases will serve as a great textbook for people in Fukushima," Mr. Asahina said in an interview. "For so long, the government rejected the notion of internal exposure," he said, referring to the ingesting of radioactive material.
There are some emerging indications that the impact of the Fukushima disaster on public health may not be as severe as some have feared. Researchers at Hirosaki University, north of Fukushima City, surveyed 5,000 affected residents at shelters in the area between March 15 and June 20 and found only 10 people with relatively high exposure levels; they weren't high enough to need decontamination.
Still, there is little science on long-term health consequences of low-level radiation. In fact, Fukushima provides the world one of the few opportunities to start filling the scientific gap.
For years after the World War II bombings, Japan kept its criteria for victim status vague, never stating one way or the other whether internal exposure (or other conditions) qualified. But before 2008, virtually all "early entrants" to the bombed areas were denied benefits, according to a health-ministry official.
Vast studies of Japan's hibakusha, "the people exposed to bombs," provide a foundation of the scientific understanding of radiation's human effects. These studies today are the basis for global nuclear-safety standards.
But hibakusha studies focused on people exposed most intensively to the blasts. They gave minimal attention to people a few miles from the blast or who visited the hypocenters later, and to people exposed over time from tainted food, rain or snow.
The 1986 nuclear accident at Chernobyl in Ukraine deepened the understanding of internal exposure. When thyroid cancer surged among children there, it was traced to contaminated cows' milk they had consumed. Still, Chernobyl data covers only a quarter-century—not enough time to study radiation's full effects—and the information isn't extensive or consistent enough, Japanese and U.S. experts say.
Critics argue that the lack of research on low-level or internal exposure means today's policies may downplay the health risks, whether for bomb survivors or for people near power plants.
"The government has always underestimated the impact of radiation exposure," says Shoji Sawada, a Hiroshima survivor and retired nuclear physicist who advocates for greater attention to the bombs' health effects.
There are big differences, of course, between the bombs and Fukushima. Estimates vary, but 150,000 to nearly 250,000 people died in the blasts. People within 2.5 kilometers (1.5 miles) received an average 200 millisieverts of radiation, according to the Radiation Effects Research Foundation in Hiroshima.
By contrast, exposure for three of the most affected towns in Fukushima were less than 5 millisieverts for 97% of the population, according to Fukushima Prefecture. A spokesman for Fukushima Daiichi's owner, Tokyo Electric Power Co., says the company isn't aware of any local residents or plant workers sickened from exposure. The spokesman says Tepco believes government officials have taken the appropriate steps to protect citizens.
The power plant, however, released more radiation than either bomb because it contained much more radioactive material.
Tatsuhiko Kodama, a physician and head of the Radioisotope Center at Tokyo University, has criticized Japan for not providing children in Fukushima enough protection from internal exposure. "We must strategize on the assumption that the Fukushima Daiichi disaster, like Chernobyl, released radiation equal to several dozen nuclear bombs and created far larger amounts of fallout," he said at a July parliamentary session.
The government has said Fukushima released cesium-137 in an amount 168 times larger than that of the Hiroshima bomb. It released about half the amount of Chernobyl, experts said. The cesium, with a half-life of 30 years, is likely the main long-term health threat from Fukushima, although prevailing winds during the March accident blew most of it out to sea.
Japanese officials admit that missteps may have exposed people to radiation. "We apologize deeply for the residents in the nearby areas who have been exposed," Yukio Edano, a minister overseeing the nuclear industry, said at a parliamentary committee meeting last month. He said the government will provide health checkups "continuously for the affected residents."
The government defends its standards, suggesting that people may have overreacted to the risk of low-level exposure. "We need to look at what exactly the impact on people's day-to-day life will be from an additional exposure of one or two millisieverts," says Goshi Hosono, state minister in charge of the Fukushima accident. "We may still need to ask people to continue with their lives after taking into account such impact."
Two years after the U.S. bombed Hiroshima and Nagasaki, the American occupation in 1947 launched studies of survivors. The studies continue today under the Radiation Effects Research Foundation, or RERF, funded by the U.S. and Japan.
Over decades, some 120,000 survivors were tracked. Exposure was based on people's distance from the blasts, adjusted for whether they were shielded by a building, for instance.
The research didn't take into account the effects of fallout over time, and "didn't encompass the impact of internal exposure," for the most part, says Takanobu Teramoto, RERF's permanent director. "We didn't have data on people's detailed behaviors that would have allowed us to estimate that."
For decades, Japan's official conclusion from the study was that about 1% of the 400,000 hibakusha had radiation-induced problems, and the government compensated them. Among the 99% of hibakusha deemed unaffected were tens of thousands who lived a few miles from the hypocenters, or those who, like the megaphone-wielding Mr. Asahina, were "early entrants."
When hibakusha claiming just low-level exposure started seeking compensation in the 1960s, they faced a kind of Catch-22: They were told there was no conclusive evidence to prove health effects, because low-level exposure hadn't been studied. Many claimed ailments similar to people who had been hit directly by the blast: hair loss, bleeding and, years later, cancer, cataracts and heart problems.
They took to the courts, launching a remarkable decades-long debate—part scientific, part legal—over low-level radiation risks. The cases offer some of the most comprehensive records assembled on a question today at the heart of assessing Fukushima's potential danger.
The movement built slowly. But in 2000, the Supreme Court sided with a Nagasaki woman who linked her partial paralysis to exposure and proximity to the blast, some 2.5 kilometers away. The court also ruled the government should consider compensating hibakusha who received low-level radiation at greater distances.
That ruling opened the gates. Since 2006, about 300 hibakusha have won in 30 class-action suits nationwide.
In many, judges ruled "early entrants" should also get benefits. In effect, this was the first official acknowledgment that internal exposure could cause health problems, given that these people weren't exposed to the blasts, but to later fallout.
In 2008 Japan eased its criteria for survivor benefits, granting them to people with certain health problems who were within 3.5 kilometers of the epicenters, compared to 1-to-2 kilometers previously. In addition, "early entrants" who went near hypocenters within 100 hours of the bombings are now included.
Now, just as the court cases are winding down, debate over Fukushima is building. Discovery of radiation in autumn rice crops from Fukushima has put people on alert. The government is expected soon to unveil a timeline for the return of residents evacuated from the 20-kilometer zone around the nuclear plant.
In making key decisions, Tokyo has relied on guidelines from a Canada-based scientific body, the International Commission on Radiological Protection, that used the Hiroshima-Nagasaki studies as a cornerstone.
Many radiation experts say a population will face a measurable cancer increase only if exposed to doses defined as 100 millisieverts or more in a short period. The commission suggests a policy of limiting people's exposure after a nuclear accident to the "lower part of the 1-20 millisievert-per-year band." As the Fukushima disaster unfolded, these guidelines shaped Tokyo's decision to evacuate areas with estimated annual exposure above 20 millisieverts, the government has said.
The ICRP guidelines don't come from firsthand studies of exposure at those levels, but are extrapolated from the much higher exposure levels from the bombs. In Japan, 300 out of 1,000 deaths annually are cancer-caused. If the population is exposed to 100 millisieverts of radiation, it would rise to an estimated 305, according to the National Institute of Radiological Sciences of Japan, partly as victims tend to develop cancer earlier than the general public.
But some medical experts argue that's just guesswork. One theory: Extended low-level exposure might actually be more hazardous than a one-time blast if a brief, high dose just kills cells, whereas internal exposure could damage them even at low levels, ultimately causing cancer. Other experts say it's simply prudent to use extra caution on low-level exposure, since little data exists.
The ICRP guidelines reflect the "general consensus of scientific experts," says Michiaki Kai, a professor at Oita University of Nursing and Health Sciences and ICRP committee member. "It is true the risk is uncertain for very low-level radiation. The question is how to respond to that uncertainty. It's an ethical question, not a scientific one." Should people stay away "until radiation levels return to zero?" he asks. "Or shall we allow them to go home before that so they can resume their lives?"
Dale Preston, an American researcher of hibakusha at RERF for more than two decades, says the studies demonstrated radiation exposure did increase cancer risk even at low doses, but in proportion to the dose size. "In no analyses was there any evidence of larger-than-expected risks at low doses," he says.
Several experts and advocates from the fight over Hiroshima and Nagasaki are now joining the Fukushima debate.
Shuntaro Hida, a doctor at a Hiroshima hospital at the time of the bombing who has treated more than 6,000 survivors, was the key expert witness in a class-action suit in Osaka that concluded in 2006. There he described in detail the symptoms of "early entrants" and told the story of a young woman who entered Hiroshima a week after the bombing, searching for her husband, who quickly died from hemorrhaging.
Now 94 years old, Mr. Hida is again in the spotlight. He says he received calls from more than 50 readers of his recent book on internal radiation exposure—mostly from anxious mothers—after Fukushima. One woman was frantic that cesium was detected in her breast milk, he says. Others worried that their children's nosebleeds or canker sores were tied to radiation.
"I say to them, once radiation enters your body, there is no reversing it, and that there is no medicine," Mr. Hida says. "I tell them, now it's up to them to have a positive attitude."
Mr. Asahina, the Hiroshima survivor, says he brought his megaphone to the train station because he fears people will do what he did as a young man and simply avoid the issue of radiation exposure. As a 13-year-old middle-school student, he approached the hypocenter two days after the blast, he says, to look for bodies of his classmates. He found only buttons and belts.
Soon Mr. Asahina showed symptoms of acute radiation sickness, including hair loss and bleeding gums. But once the moment passed, he says, he tried to forget those days, despite years of health problems, until his cancer finally struck.
"We Japanese tend to look the other way when something really awful happens," Mr. Asahina says. "We need to learn to face it."
—Robert Lee Hotz contributed to this article.
Write to Yuka Hayashi at yuka.hayashi@wsj.com
No comments:
Post a Comment