Last March, the 9.0 magnitude Tōhoku earthquake triggered a tsunami that sent over 45-foot waves of water crashing down on the reactors at the Fukushima Dai-ichi Nuclear Power Plant, causing the largest nuclear disaster since Chernobyl in 1986. While health officials scrambled to quickly stabilize the situation, it was unclear how much radiation had made it out of the plant—and how it could affect people, plants, and animals who came into contact with it.
Preliminary studies concluded that most of the 140,000 people in the surrounding areas of Fukushima had probably been exposed to relatively low doses of radiation that probably wouldn't lead to any adverse health effects. But a new study published last week in Nature has shown that the radiation is causing a particularly sensitive population—the pale grass blue butterfly—to develop a slew of uncommon and potentially lethal physical abnormalities.
Researchers collected butterflies immediately following the nuclear meltdown and six months later, both from the surrounding areas of Fukushima and from various other localities in Japan where the butterfly is common. As compared with the butterflies collected from elsewhere in the country, Fukushima butterflies showed some abnormally-developed legs, dented eyes, deformed wing shapes, and changes to the color and spot patterns of their wings, with an overall abnormality rate of around 12 percent.