Sunday, March 4, 2012

Japan's Post-Fukushima Earthquake Health Woes Go Beyond Radiation Effects

News | Health

Heart disease and depression are likely to claim more lives than radiation after the earthquake, tsunami and nuclear accident, experts say


Volunteers at Minamisoma city, Fukushima pref. The city was severly damaged by the Tsunami of Japan Earthquake and Fukushima Daiichi nuclear plant accident. Image: Flickr/jetalone

After the March 11, 2011, earthquake and tsunami crippled Japan's Fukushima Daiichi nuclear power plant, worry about the unfolding nuclear accident quickly commandeered international headlines. Even after the situation was brought under relative control over subsequent days and weeks, public concern hung on the threat of radiation almost more than it did than on the tsunami and earthquake themselves, which had killed more than 15,850 people and displaced at least 340,000 more.

A year out, public health experts agree that the radiation fears were overblown. Compared with the effects of the radiation exposure from Fukushima, "the number of expected fatalities are never going to be that large," says Thomas McKone, of the University of California, Berkeley, School of Public Health.

And some, including Richard Garfield, a professor of Clinical and International Nursing at Columbia University's Mailman School of Public Health, go a step further. "In terms of the health impact, the radiation is negligible," he says. "The radiation will cause very few, close to no deaths." But that does not mean that the accident has not already caused wide-reaching health issues. "The indirect effects are great," Garfield says.

Reacting over radiationThe prospect of invisible radioactive material contaminating the air and ground is terrifyingespecially for a country that experienced two nuclear bomb attacks in 1945.

In the aftermath of the earthquake the situation seemed dire, as buildings crumbled and workers were exposed to lifetime doses of radiation in a few hours. But in retrospect, the power plant's malfunction was relatively well contained. The reactor shut down, as designed, at the time of the earthquake. "It was nowhere near as complex of a release as Chernobyl, which was everything from the core of the reactor," says Peter Caracappa, a radiation safety officer and clinical assistant professor of nuclear engineering at Rensselaer Polytechnic Institute in Troy, N.Y. "This was a slow release," he adds, and it was limited to a few radioactive materials, including iodine 131, which has a half-life of just eight days and therefore does not lead to long-term contamination. And for other isotopes, such as cesium 134 (three-year half-life) and cesium 137, (30 years), levels can be easily detected and dangerous areas kept clear.

And the Japanese government, although criticized immediately after the accident for providing spotty information, actually gave relatively good instructions to local residents. In particular, it wisely asked people to shelter in place before evacuating potentially dangerous areas, says Kathryn Higley, head of the Nuclear Engineering and Radiation Health Physics department at Oregon State University.

The government, armed with reliable maps of where radiation levels were highest, has tailored its advice to local circumstances. Owing to the weather patterns just after the accident, most of the radioactive fallout landed northwest of the Fukushima complex. So for that area, the government has kept the recommended evacuation distance at 30 kilometers. But to the south, a distance of 20 kilometers sufficesand even that, Caracappa says, is more for logistical reasons (keeping roads clear for cleanup crews) than for radiation dangers.

The exposure cutoff for the evacuated areas is an estimated 20 millisieverts per year. (A sievert is a unit of ionizing radiation equal to 100 rems; a rem is a dosage unit of x-ray and gamma-ray radiation exposure.) That is more radiation than the typical U.S. resident is exposed to in an average year, but not that much more, Caracappa says. Taking into account natural background radiation, medical procedures and other sources, people in the U.S. encounter an average of about 6.5 millisieverts per year. Although that extra exposure can increase cancer risk, the effect is very small. A 20-millisievert-per-year exposure might increase the odds of getting cancer by a few thousandths of a percent.

Source: http://rss.sciam.com/click.phdo?i=acf849dbe1251a2b3eafeeb5be778d5f

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