Genetic mutations

The butterflies found to be deformed as a result of radiation from the nuclear meltdown in Fukushima belong to the butterfly family of gossamer-winged butterflies.

These butterflies can be found throughout the world. They are very sensitive to changes in the environment - to water and air pollution, chemicals and radioactivity.

For scientists, gossamer-winged butterflies are thus a good biological indicator of the health of the environment. When they get sick, it means there is a problem somewhere in the ecosystem - even if there don't seem to be any apparent problems, Winfrid Eisenberg, radiation expert and member of International Physicians for the Prevention of Nuclear War (IPPNW), told DW.

"The findings of the Japanese scientists don't surprise me. There were similar findings in studies conducted after Chernobyl," he explained.

Deformed buts, mice, birds

After the nuclear disaster in Chernobyl in 1986, deformities similar to the ones recently seen in butterflies in Fukushima were also observed in plant insects.

Even today, Eisenberg said researchers continue to find around 100 times more genetic mutations in field mice, now the 52nd generation since the disaster, than in mice in uncontaminated areas.

Swallows were also greatly affected. In Chernobyl and its surrounding area, the birds are as good as extinct. The ones that do still exist there have "very small heads and very low success rates in breeding," Eisenberg explained.

But not only animals and insects pass on genetic defects to their offspring. Nine months after Chernobyl, there was a significant increase in the number of babies born with trisomy 21 (also known as Down syndrome) - a disease in which there is one copy too many of chromosome 21 in the DNA.

During that time, the number of deformities and miscarriages was especially high - even outside of Chernobyl. According to a report by the Society for Radiation Protection, there are between 18,000 and 122,000 people who have genetic defects as a result of the Chernobyl disaster throughout Europe.

Even small amounts of radiation can be dangerous

The minimum dose of radiation cells can be exposed to before mutating is unclear. Peter Jacob, head of the Institute for Radiation Protection at the Helmholz Center in Munich, told DW that even small quantities of radiation was enough to cause damage.

But human cells have remarkable defense mechanisms that have evolved throughout time. Should any abnormalities occur during cell division, certain enzymes make sure that most of them are repaired. But a quick repair after short-term exposure to radiation could lead to further mutations, which are then passed on to the next generation of cells. In the long term, that could lead to cancer. And if the mutations happen to be in sperm or egg cells, there is a much higher risk that such disease-causing mutations can be passed down for generations.

Fear of diseases

A study conducted by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) found that the number of cases of thyroid cancer and leukemia in Japan would not rise significantly as a result of the reactor meltdown in Fukushima. Yet Eisenberg said the deformed butterflies spoke for themselves, even if findings in research on animals and insects could not completely speak for humans.

A series of ultrasound examinations conducted on over 40,000 children in Japan found 35 percent of the children to have lumps or cysts.

"That is not normal among children," Eisenberg, who is also a retired pediatrician, told DW. He added that the figure was alarming. He, along with some of his colleagues, requested access to Japan's birth statistics for the time since the disaster at the Daiichi nuclear power plant in Fukushima. As of now, he is still waiting for access to be granted.

Author: Judith Hartl / sb
Editor: John Blau