It has been 18 months since the 9.0-magnitude quake that devastated life on the Japanese coast. The deadly disaster was also responsible for the nuclear outbreak at Japan’s Fukushima Daiichi power plant. And this week, researchers suggest the nuclear fallout is affecting environmental species in the region.
A new study says about 12 per cent of pale grass blue butterflies exposed to nuclear radiation immediately after the disaster had abnormalities. These abnormalities include smaller wings and damaged eyes.
Joji Otaki is associate professor at Ryukyu University in Okinawa, southwestern Japan. He spoke to the Associated Foreign Press (AFP) about the study. Otaki explains the insects were mated in a laboratory well outside the fallout zone. And 18 per cent of their offspring displayed similar problems. That figure rose to 34 per cent in the third generation of butterflies, even though one parent from each coupling was from an unaffected population.
The researchers also collected another 240 butterflies in Fukushima in September last year. That was six months after the disaster. Abnormalities were recorded in 52 per cent, which is considered a dominantly high ratio. Otaki said the high ratio could result from both external and internal exposure to radiation from the atmosphere and in contaminated foodstuffs.
Otaki then carried out a comparison test in Okinawa exposing unaffected butterflies to low levels of radiation. He says the results showed similar rates of abnormality.
“We have reached the firm conclusion that radiation released from the Fukushima Daiichi plant damaged the genes of the butterflies,” Otaki said.
The results of the study were published in Scientific Reports, an online research journal from the publishers of Nature.
The quake unleashed a sprawling tsunami in March 2011. The powerful waves knocked out cooling systems at the Fukushima Daiichi nuclear power plant, causing three reactors to go into meltdown. This accident has been considered the world’s worst atomic disaster in 25 years.
The latest findings will likely trigger fears over the long-term effects of the leaks on people, who were exposed in the immediate aftermath of the accident. The radiation spread over a vast area and forced thousands to evacuate.
But Otaki has warned it is too soon to jump to conclusions. He says his team’s results on the Fukushima butterflies could not be directly applied to other species, including humans. He says he and his colleagues will have to conduct follow-up studies, including similar tests on other animals.
Since the Fukushima disaster, many researchers and medical doctors have denied the accident would cause an elevated incidence of cancer or leukaemia. These are diseases that are often associated with radiation exposure. But they do agree that long-term medical examination is needed based on concerns over thyroid cancer among young people. Reports say this is a particular problem for many victims exposed to the Chernobyl catastrophe.
According to official data, no one has been recorded as having died as a direct result of the Fukushima disaster. But local reports suggest many who still live in, and fled, the immediate area worry about the long-term effects of nuclear exposure.