Two years have passed since the Fukushima Daiichi nuclear disaster, which followed the Tohoku earthquake and tsunami on March 11, 2011. One of the world's foremost experts on the consequences of Fukushima as well as 1986's Chernobyl disaster is biologist Tim Mousseau of the University of South Carolina's College of Arts and Sciences.
Mousseau studies the effects of radiation on wildlife in their natural surroundings. He began scientific expeditions to the Chernobyl exclusion zone in 2000, and with collaborators including Anders Mψller of the CNRS (France) established the Chernobyl Research Initiative, which has now published more than 40 research papers. He has organized multiple scientific expeditions to investigate the consequences of the radioactivity release from Fukushima, first traveling to the site in July 2011 and since publishing several research papers based on studies of the area surrounding the epicenter of the meltdowns.
"The most important thing we've learned so far is just how little we understand about the role played by low-level, low-dose radiation in natural environments," Mousseau said. "What we've learned over the last seven or eight years -- in Chernobyl in particular -- is that the impacts of radiation under natural conditions, in the field, are much greater than what people had seen in the laboratory setting, and they're much greater than people had seen for the so-called 'pure' external-dose radiation, such as much of the work that has been done with atomic bomb survivors.
"It's very clear, based on recent studies by other folks in addition to us, that the effects of radiation on natural populations -- those that experience the full range of natural stress, in addition to the radiation -- are much larger than the effects in the other settings."
Mousseau's work also challenges the widely held notion that low-level radiation, below a certain threshold, is in fact harmless. "We see no threshold," Mousseau said. "We see consequences -- such as in terms of mutation rates, or lowered fertilities and other population consequences -- all the way down to very low levels, levels that are much lower than what people previously had thought could be measurable in the wild.
"This is mainly because we've put a lot of effort into very carefully designed experimental studies. We have repeated our studies at many different locations in order to be able to factor out other contributing variables to variation in natural populations. This approach has allowed us to use sophisticated statistical procedures to control for many of the other environmental sources of variation so we can analyze the radiation effects independently of these other factors than can obscure the influences of the radiation effects. And when we do this, in a careful way, we find no threshold below which there aren't effects."
In contrast to Chernobyl, the situation in Fukushima remains difficult to assess because it's still very early since the radioactivity release. "It's been two years, and we're just starting to get a handle on what's going on there," Mousseau said. "Based on our analyses the first summer, three to four months after the event, we noticed very significant declines in many of the bird species. Not all of them, but many of the species of birds were negatively impacted, as well as butterflies, which in particular were dramatically impacted. Cicadas were another group that were also negatively impacted. But we didn't see any measurable effects on, say, grasshoppers, dragonflies and some of the other groups. This was the first year, the first few months after the event.
"We went back last year, year two, and we noted that there were increasing negative effects in the most contaminated areas on the birds and some of these insects," Mousseau said. "So at this point, we're hoping to go back there this summer to continue these surveys to see how things continue to progress in the future -- do they bounce back, or do they continue to be affected by both the direct exposure that's still there and perhaps the cumulative effects of mutations accumulating over multiple generations as well?
"There was a really wonderful study done by a group of Japanese scientists at Okinawa University," Mousseau added. "They demonstrated that the butterflies living in Fukushima were experiencing dramatically elevated rates of genetic mutations, and this was being reflected in all sorts of developmental abnormalities -- deformities in the wing structure and in their legs and antennae that were clearly impacting their ability to survive and reproduce."
Research support remains a significant problem, though. "The truth is that there is minimal funding available for independent scientists to conduct research in either place," Mousseau said. "Among the scientific community that is not associated with the nuclear industry or the nuclear agencies, there is virtually no funding for this kind of work. In our case, though, we are particularly grateful for continuing support from the Samuel Freeman Charitable Trust, which has been a friend to the University of South Carolina for a long time."
"The response of most of the U.S. agencies has been that this is a problem for Japan, and that the Japanese should be funding this research. Another response has been that this is not the sort of science that we typically fund because it's not consistent with the mission of the given agency. Clearly, both responses are short-sighted given the urgent need for basic research in this area."
This week Mousseau is a participant in a symposium, "The Medical and Ecological Consequences of the Fukushima Nuclear Accident" on March 11 and 12, 2013, held at The New York Academy of Medicine. The event is being live-streamed.
More information concerning Mousseau's research in Chernobyl, Fukushima and other "hot" places can be found on his website: http://cricket.biol.sc.edu/chernobyl/
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