Top Expert Debunks Radiation Myths

George Washington's picture

Many have claimed that wildlife is thriving in the highly-radioactive Chernobyl Exclusion Zone.

Some claim that a little radiation is harmless … or even good for you.

One of the main advisors to the Japanese government on Fukushima announced:

If you smile, the radiation will not affect you.   If you do not smile, the radiation will affect you.


This theory has been proven by  experiments on animals.

Are these claims true?

We Ask an Expert

To find out, Washington's Blog spoke with one of the world’s leading experts on the effects of radiation on living organisms: Dr. Timothy Mousseau.

Dr. Mousseau is former Program Director at the National Science Foundation (in Population Biology), Panelist for the National Academy of Sciences’ panels on Analysis of Cancer Risks in Populations Near Nuclear Facilities and GAO Panel on Health and Environmental Effects from Tritium Leaks at Nuclear Power Plants, and a biology professor – and former Dean of the Graduate School, and Chair of the Graduate Program in Ecology – at the University of South Carolina.

For the past 15 years, Mousseau and  another leading biologist – Anders Pape Møller – have studied the effects of radiation on birds and other organisms.

Mousseau has made numerous trips to the Chernobyl Exclusion Zone and Fukushima – making 896 inventories at Chernobyl and 1,100 biotic inventories in Fukushima as of July 2013 – to test the effect of radiation on plants and animals.

On the third anniversary of the Fukushima disaster, we spoke with Dr. Mousseau about what he discovered regarding the effects of radiation on plants, animals … and people.

[Question] How did you get into this field? Is it because you are an anti-nuclear activist?

[Mousseau]  No.

I’m an activist, but not an anti-nuclear scientist. I’m an activist for evidence-based science policy.

I got into this out of an interest in discovery of new forms of adaption to changing environments. I’m an evolutionary biologist by training. And – about a decade and a half ago – I met up with Anders Pape Møller, one of the world’s leading ornithologists.

We decided to go to Chernobyl and see if the females, the mothers, are doing anything to enhance their offspring’s fitness in response to this novel stressor of radioactive contaminants.

And then in 2005, when the international Atomic Energy Agency commissioned this report by a panel – the Chernobyl Forum – and the Chernobyl Forum put out their first release in 2005, followed by their main publication in 2006, we realized they didn’t cite anybody’s work that went against their dogma that contamination levels at Chernobyl were just too low to be of any profound significance for biological communities.

In fact, they have a statement in the Chernobyl Forum report where they suggest that the plants and animals are thriving because there are no people there.  And – by implication – the suggestion is that the radiation isn’t a problem.

[Q] What did you actually find in the field?

[Mousseau] What we observed was that in the more contaminated parts of the Chernobyl zone, there were many fewer critters, fewer birds singing, and we noticed there were no spider webs getting in our face.

We set up a quantitative design to measure the critters not only in the most contaminated areas, but also in the clean areas.  In the Chernobyl Exclusion Zone,  you have everything from pristine, completely uncontaminated areas to really highly-contaminated areas.  It’s kind of a quiltwork … a mosaic.

So this provides the ability to do rigorous comparative analyses of critters that are in the same environment, except for the radiation.

[Q] So you utilized good controls in terms of ruling out other health-damaging and mortality factors, because in this “quiltwork” ecology you had higher or lower levels of radiation … but otherwise the conditions were similar?

[Mousseau] Exactly, combined with the fact that – everywhere we went – we also measured all of the other environmental factors that would likely play some role in the abundance and distribution of organisms … such as the type of soil, whether it was forest or grass, the water, as well as the ambient conditions at the time we collected the data.

And we did a control for human habitation sites as well, in Belarus.

[Q] What kinds of effects did you test for?

[Mousseau] We’ve tested for mutation rates, estimates of genetic damage, estimates of sperm damage, sperm swimming [i.e. how mobile the sperm are], fertility rates in both females and males, longevity, age distribution of the birds in these different areas, species diversity, etc.

[Q] And what did you find?

[Mousseau] The diversity of birds is about half of what it should be in the most contaminated areas.  The total numbers of birds is only about a third of what it should be in the most contaminated areas.

In 2006, I decided to collect fruit flies across the Chernobyl Exclusion Zone, and I couldn’t find very many.

And then I realized, there wasn’t any rotting fruit on the ground.  And considering that every farmer, every landowner would put up fruit trees in that part of the world, you look at the fruit trees and realize there’s hardly any fruit on them.

And of course, that’s why there weren’t many fruit flies.

And then it dawned on us, where are the pollinators? And that point, we realized there aren’t many bees and butterflies.

So we started counting the bees, the butterflies, the dragonflies, the spiders, and the grasshoppers.

And that’s when we realized that all of the groups we looked at showed significantly lower numbers in the most-contaminated areas.

It look us a little longer to figure out a way to study mammals. We decided we can count many of the mammals by looking at footprints in the snow. The ecologists in Canada and Northern Europe have been doing this for centuries. There’s even a book published [a field guide] for identifying animals by their footprints in the snow.

We found – for most of the mammals – significant declines in numbers in the most contaminated areas. The one exception were the wolves, which showed no difference, probably because they have huge ranges which span across the high and low areas of contamination.

[We'll cut away from the interview to explain what Mousseau found, using information and slides from his published studies. The copyright to all images are owned by Dr. Mousseau.]

Indeed, Mousseau found – in studies of plants, insects and mammals – that:

  • Most organisms studied show significantly increased rates of genetic damage in direct proportion to the level of exposure to radioactive contaminants
  • Many organisms show increased rates of deformities and developmental abnormalities in direct proportion to contamination levels
  • Many organisms show reduced fertility rates
  • Many organisms show reduced life spans
  • Many organisms show reduced population sizes
  • Biodiversity is significantly decreased many species locally extinct
  • Mutations are passed from one generation to the next, and show signs of accumulating over time
  • Mutations are migrating out of affected areas into populations that are not exposed (i.e. population bystander effects)

(Click any image for bigger, better version.) He found that the numbers of birds plummeted:

And biodiversity significantly declined:

The same is true for bees:


And mammals:

Examples of abnormalities Mousseau found include cataracts, albinism, and tumors:

And he found that the brains of birds in high-radiation areas are smaller.

[Back to the interview.]

[Q] Aren’t humans totally different from the plants and animals you’ve studied?

[Mousseau] Most medical research is conducted with either animal models or cell lines. What’s the reason? Because we can look at the effects very clearly in these animal populations.

And we’re just animals … so what happens to animals is likely to be of relevance to humans as well.

[However, since humans live longer than most animals - and much longer than birds or bacteria - it can take longer to see genetic mutations due to radiation.]

[Q] What about people who say that low doses of radiation are actually good for you, what’s called “radiation hormesis?”  And I don’t know if you’ve heard this, but some Department of Energy articles have tried to push that theory.

[Mousseau] Most of those reports have been generated as a result of energy-related funding.  And the data which supports the theory is really shaky … and even flaky.

We conducted meta-analysis a couple of years ago published in the Cambridge Biological Review. We analyzed all of the published we could find that was conducted with any kind of scientific rigor for naturally radioactive areas around the world.

And the idea is that there has been plenty of time in these natural hotspots for organisms to adapt and evolve and show adaptive responses and even hormetic responses.

And there was no indication in this meta-analysis that hormesis was playing any role in any of these populations, and certainly not the human populations.

[Q]  Did your meta-review include human studies?

[Mousseau] Yes, it included everything we could find.

[Q]  Did your research back up the linear no threshold model of radiation [the prevailing scientific view of radiation, which is that there is no safe dose]?

[Mousseau]. Damage increases down to very low levels of radiation.  There’s no indication that the effect disappears at low doses.

Science Daily summarized Mousseau’s findings in 2012:

Even the very lowest levels of radiation are harmful to life, scientists have concluded in the Cambridge Philosophical Society’s journal Biological Reviews. Reporting the results of a wide-ranging analysis of 46 peer-reviewed studies published over the past 40 years, researchers from the University of South Carolina and the University of Paris-Sud found that variation in low-level, natural background radiation was found to have small, but highly statistically significant, negative effects on DNA as well as several measures of health.


The review is a meta-analysis of studies of locations around the globe …. “Pooling across multiple studies, in multiple areas, and in a rigorous statistical manner provides a tool to really get at these questions about low-level radiation.”


Mousseau and co-author Anders Møller of the University of Paris-Sud combed the scientific literature, examining more than 5,000 papers involving natural background radiation that were narrowed to 46 for quantitative comparison. The selected studies all examined both a control group and a more highly irradiated population and quantified the size of the radiation levels for each. Each paper also reported test statistics that allowed direct comparison between the studies.


The organisms studied included plants and animals, but had a large preponderance of human subjects. Each study examined one or more possible effects of radiation, such as DNA damage measured in the lab, prevalence of a disease such as Down’s Syndrome, or the sex ratio produced in offspring. For each effect, a statistical algorithm was used to generate a single value, the effect size, which could be compared across all the studies.


The scientists reported significant negative effects in a range of categories, including immunology, physiology, mutation and disease occurrence. The frequency of negative effects was beyond that of random chance.




“When you do the meta-analysis, you do see significant negative effects.”


“It also provides evidence that there is no threshold below which there are no effects of radiation,” he added. “A theory that has been batted around a lot over the last couple of decades is the idea that is there a threshold of exposure below which there are no negative consequences. These data provide fairly strong evidence that there is no threshold — radiation effects are measurable as far down as you can go, given the statistical power you have at hand.”


Mousseau hopes their results, which are consistent with the “linear-no-threshold” model for radiation effects, will better inform the debate about exposure risks. “With the levels of contamination that we have seen as a result of nuclear power plants, especially in the past, and even as a result of Chernobyl and Fukushima and related accidents, there’s an attempt in the industry to downplay the doses that the populations are getting, because maybe it’s only one or two times beyond what is thought to be the natural background level,” he said. “But they’re assuming the natural background levels are fine.”


“And the truth is, if we see effects at these low levels, then we have to be thinking differently about how we develop regulations for exposures, and especially intentional exposures to populations, like the emissions from nuclear power plants, medical procedures, and even some x-ray machines at airports.”

Postscript: To support Dr. Mousseau’s important research, please consider making a donation to the University of South Carolina’s Chernobyl and Fukushima Research Initiative (specify that the donation is to support Mousseau’s research.)