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Anomalies in wildlife and the ecosystem around Chernobyl and Fukushima

 

Dr. Timothy Mousseau, Professor of Biological Sciences, University of South Carolina. Mousseau discussed his many studies on the health impacts on wildlife and biota around Chernobyl and Fukushima which soundly debunk the notion that animals there are “thriving.”

April 9, 2017 Posted by | radiation | , , , , , | Leave a comment

Blind mice and bird brains: the silent spring of Chernobyl and Fukushima

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Radioactivity warning sign on the hill at the east end of Chernobyl’s Red Forest, so called due to the characteristic hue of the pine trees killed by high levels of radiation after the disaster

Evolutionary biologist Timothy Mousseau and his colleagues have published 90 studies that prove beyond all doubt the deleterious genetic and developmental effects on wildlife of exposure to radiation from both the Chernobyl and Fukushima nuclear disasters, writes Linda Pentz Gunter. But all that peer-reviewed science has done little to dampen the ‘official’ perception of Chernobyl’s silent forests as a thriving nature reserve.

Dr Timothy Mousseau has published more than 90 peer reviewed articles in scientific journals, related to the effects of radiation in natural populations (and more than 200 publications in total).

He has spent 16 years looking at the effects on wildlife and the ecosystem of the 1986 Chernobyl nuclear disaster.

He and his colleagues have also spent the last five years studying how non-human biota is faring in the wake of the 2011 Fukushima nuclear meltdowns in Japan.

But none of this work has received anything like the high profile publicity afforded the ‘findings’ in the 2006 Chernobyl Forum report which claimed the Chernobyl zone “has become a wildlife sanctuary”, and a subsequent article published in Current Biology in 2015 that said wildlife was “thriving” around Chernobyl.

“I suppose everyone loves a Cinderella story”, speculated Mousseau, an evolutionary biologist based at the University of South Carolina. “They want that happy ending.” But Mousseau felt sure the moment he read the Forum report, which, he noted, “contained few scientific citations”, that the findings “could not possibly be true.”

Ninety articles later, Mousseau and his research partners from around the world are able to demonstrate definitively and scientifically that non-human biota in both the Chernobyl zone and around Fukushima, are very far indeed from flourishing.

Far from flourishing around Chernobyl, birds and animals are fading

What Mousseau found was not unexpected given the levels of radiation in these areas and what is already known about the medical effects of such long-term exposures. Birds and rodents had a high frequency of tumors.

“Cancers are the first thing we think about”, Mousseau said. “We looked at birds and mice. In areas of higher radiation, the frequency of tumors is higher.” The research team has found mainly liver and bladder tumors in the voles and tumors on the head, body and wings of the birds studied, he said.

But Mousseau wanted to look beyond cancers, which is what everyone expects to find and what researchers had looked for, but only in humans. There were few wildlife studies, a fact Mousseau found surprising, given nature’s ability to act as a sentinel for likely impending human health impacts.

Mousseau and his fellow researchers found cataracts in birds and rodents. Male birds had a high rate of sterility. And the brains of birds were smaller. All of these are known outcomes from radiation exposure.

“Cataracts in birds is a problem”, Mousseau said. “A death sentence.”

Mental retardation has been found among children exposed to radiation in utero. Mousseau and colleagues discovered the same pattern in the birds they studied. “Birds already have small brains, so a smaller brain size is a definite disadvantage”, he said.

Almost 40% of male birds examined were sterile

There were also just fewer animals in general. “There were many fewer mammals, birds and insects in areas of higher radiation”, Mousseau said. And they had their hunch as to why.

He and his colleagues extracted sperm from the male birds they caught and were shocked to find that “up to 40% of male birds in the radiologically hottest areas were sterile.”

The birds’ sperm were either deformed or dead. None would be able to reproduce. The discovery, he said, was “not at all surprising. These are the levels of radiation known to influence reproduction. At the same time, there is no safe level of radiation below which there aren’t detectable effects.”

Fewer birds have already been observed in the contaminated areas around Fukushima, said Mousseau. “Although it’s too early to assess the long term impact on abundance and diversity around Fukushima, there are very few butterflies and many birds have declined in the more contaminated areas. If abundance is compressed, biodiversity will follow.”

Five years into the still on-going Fukushima disaster, Mousseau’s research continues to uncover “a dramatic reduction in the number of birds and numbers of species in areas of high radiation”, he said.

At least in that region, Japan could be headed toward a Silent Spring.

No doubt that Fukushima and Chernobyl are causing genetic damage

The consequences of radiation exposure, says Mousseau, “will have a tremendous impact on the quality of life of these animals, and the length of quality of life. It need not necessarily be cancers”, that cause these damages he said. “There is no doubt that the levels of radiation in Chernobyl and Fukushima generate genetic damage.”

A study by Mousseau et al. that did get some attention, most notably from the Smithsonian Institution, found disturbing changes in the decomposition of organic matter in the Chernobyl Zone.

Fungi and other microorganisms are decomposing at half the usual rate. Trees fall but rot unusually slowly. Leaf matter piles up without much decay, creating a tinder-box risk in the event of forest fires, several of which have occurred in the Zone.

“There is an accumulation of highly radioactive organic matter” in these areas, Mousseau said. All of this could be lofted into the air during a forest fire and redistributed as radiological contamination elsewhere, he points out.

Indeed, a map in an April 2006 edition of National Geographic Magazine, shows that this has already happened, expanding the Chernobyl Zone from its original 30km radius. High-altitude winds swept radioactive smoke and ash across a wider area, which scientists traced from soil levels of cesium 137, a long-lived isotope,” read the map’s caption. Major forest fires in the Chernobyl Zone in 2010 and 2015 have likely worsened the situation.

While the radiation spread by Chernobyl fell mostly on land, where it is easier to study the medical effects on humans and animals, the initial Fukushima radioactive plume blew mainly out to sea. And since 2011 when the accident began, further dumping of radioactive water into the Pacific has occurred.

A responsibility to protect the environment and wildlife, not just man

This has led to speculation – and some unscientific and alarmist rumors – that sea life in the Pacific is collapsing due to the Fukushima radiation.

“Catastrophic marine events started 40-50 years ago”, Mousseau points out. “Bird populations in the Pacific were in decline long before Fukushima.”

One important cause, says Mousseau, is “plastics in the environment that are consumed by marine animals which were in downward spirals long before the Fukushima accident.” Marine population decline has likely also been “compounded by climate change”, he says.

Indeed, Mousseau, who grew up on Vancouver Island in British Columbia, remembers the local harbor encrusted with star fish when he was a child. Recently, when he took his son there, he found none.

Fukushima cannot necessarily be blamed, as some would wish, but the compounding and potentially synergistic effect of radiation in the Pacific could still be taking its toll, Mousseau avowed.

“We don’t know how different environmental stresses interact with each other”, he said. “They could be synergistic and related. There is almost no research on this even in the Pacific off Fukushima – virtually nothing on the biological consequences in really contaminated areas.”

With “little real science” to rely on, Mousseau says, “we will never know” just how much marine damage the Fukushima disaster may do.

He finds the continued lack of other independent animal studies in radioactive zones frustrating. “We have a responsibility to protect the environment and wildlife, not just man”, he said. It may be expensive and difficult to conduct these kinds of studies, but, says Mousseau, “that is not an excuse.”

http://www.theecologist.org/News/news_analysis/2987598/blind_mice_and_bird_brains_the_silent_spring_of_chernobyl_and_fukushima.html

 

 

April 28, 2016 Posted by | Nuclear | , , , , | Leave a comment

Nuclear accidents make mutant bugs and birds

Biologist Timothy Mousseau has spent years collecting mutant bugs, birds and mice around Chernobyl and Fukushima. In a DW interview, he shares some surprising insights into the effects of nuclear accidents on wildlife.

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DW: Professor Timothy Mousseau, did you collect these mutant firebugs [pictured at the top of the page]?

Timothy Mousseau: Yes, the firebugs are really an eye-opener. My research partner Anders Moller and I were visiting Chernobyl on April 26, 2011. We were wandering around Pripyat collecting flowers, to study their pollen, when Anders reached down to the ground and pulled up this little bug with red and black markings. He said: “Tim, look, it’s a mutant – it’s missing an eye spot!”

From then on we started collecting these little bugs in each place we visited, from the most contaminated parts of the Red Forest to relatively clean areas in abandoned villages. Eventually we had several hundred of these little critters. It was very obvious that deformed patterns were much more prevalent in areas of high contamination.

This is just one of many similar anecdotes about the deformed critters of Chernobyl. Literally every rock we turn over, we find a signal of the mutagenic properties of the radiation in the region.

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A pair of great tit birds collected near Chernobyl – left is normal, the individual on the right has a facial tumor

Is there a threshold of radiation below which there’s no effect?

The impact of radiation on rates of mutation, cancer and mortality varies a good deal by species. But statistically, there’s a simple relationship with dose. Small dose, small effect; big dose, big effect. There doesn’t appear to be a threshold below which there’s no effect.

Interestingly, organisms living in nature are much more sensitive to radiation than lab animals – comparing mice raised in labs and mice in the wild, exposed to identical levels of ionizing radiation, the mortality rate among wild mice is eight or 10 times that of lab mice. It’s because lab animals are protected from most stressors – like cold or hunger.

Are plants and trees affected too?

Yes, we’ve collected a lot of deformed pollen. Seen a lot of deformed trees, too. Pines often show growth-form abnormalities, even in normal areas with no radionucleotide contamination. Sometimes it’s an insect infestation, sometimes a hard freeze at the wrong time – you can find such anomalies anywhere.

But in contaminated areas of Ukraine, we have a correlation between frequency of abnormality and the Chernobyl event. It’s pretty strong evidence. There was a recent paper showing a very similar phenomenon in Fukushima. The trees there are very young, but will likely also be twisted up in knots 30 years from now!

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Mousseau’s field crew collecting pollen and insect samples on the left, with the Chernobyl reactor in the distance. Right, a mutant pine tree at Chernobyl

What are the long-term effects of radiation on animal or plant species in contaminated areas? They’ve had their genomes altered. Will mutants persist?

Well, in the long run, no. The thing is, some background rate of mutations happens constantly in every species, even in uncontaminated areas – albeit at a much lower rate than in areas contaminated by nuclear accidents. So most genetic variants have been tried already. The great majority are either neutral or slightly deleterious. If a mutation had any benefit to offer, it would already be there in the population.

So the long-term effect of nuclear accidents on biodiversity is … none?

Yes, that’s right. Over evolutionary time, we expect that populations will return to normal after the mutagen disappears. Radionucleotides decay, hot sites eventually cool down, mutations become less frequent again, and healthy animal and plant populations recolonize the sites. So the genetic status quo ante returns – except if mutations have occurred that permanently enhance fitness, but that’s very rare.

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Mousseau (left) and colleague Anders Moller recording measurements in the field at Chernobyl

Some mutations might persist for a while if they’re adaptive during the hot phase. For example, there’s selection for animals whose cells produce a higher antioxidant load, which makes them more resistant to the effects of ionizing radiation. But that protection comes at a metabolic cost. After radiation levels die down, those variants will be selected back out of the population.

Where things get complicated is when the harmful mutations are recessive, that is, when it takes two copies [one for each chromosome] for the expression of the mutation. Many mutations fall into this category. They can accumulate in populations because they’re not expressed until two copies come into the same individual [one from the mother, the other from the father].

Because of this, populations can be affected by such mutations for many generations even after the mutagen is removed, and also, via dispersal, in populations that were never affected by the mutagen.

How can radioactive contamination interact with other problems that affect ecosystems, like habitat loss or climate change?

Certainly climate change is an additional stressor that is likely to interact with radiation to affect populations. We have demonstrated that while swallows in most places have moved their breeding dates forward in response to warming, in the Chernobyl area they are actually delayed. We hypothesize that this is due to the stress from the radioactive contaminants.

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The Red Forest near Chernobyl in Ukraine presents a high risk of fire, as a lack of bacteria prevents the trees from decaying

The biggest fear at present is related to the observation of hotter and drier summers in Ukraine, and the resulting increase in number and size of forest fires. Last summer there were three large fires, and one of them burned through some very contaminated areas.

We have predicted that such events could pose a significant threat to both human populations and the environment via re-suspension and deposition of radionuclides in the leaf litter and plant biomass.

In addition to the threat of catastrophic wildfire spreading nuclear contamination, birds and mammals also move around. Do they absorb radioactive elements in their food and water in contaminated sites, carry them elsewhere, thus dispersing the contamination more widely?

Do animals move radionuclides? Yes! I did a study years ago that showed very significant amounts of radionuclides are exported every year by birds. But it seems unlikely that the amount is enough to cause measurable health effects – unless you’re eating the birds. It is known that some people living outside the Chernobyl Exclusion Zone are getting very significant doses from hunting the contaminated wild boar that leave the zone.

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Mouse with cataract collected near Chernobyl – the more radioactive the site, the higher the frequency of defects

This year marks five years since the Fukushima accident, and 30 years since Chernobyl. How long will the contaminated zones around Chernobyl and Fukushima be mutagenic and dangerous?

Chernobyl was a nuclear fire and ongoing fission event for 10 days, with strontium, uranium and plutonium isotopes strewn into the landscape. They have long half-lives, so many areas will remain hazardous for centuries, even thousands of years.

Fukushima was largely a cesium event, and cesium radionucleotides have a relatively short half-life. The area will mostly naturally decontaminate itself within decades, at most within a couple hundred years.

Timothy Mousseau is a professor of biological sciences at the University of South Carolina in Columbia, South Carolina. He is one of the world’s leading experts on the effects of radionucleotide contamination from nuclear accidents on wild bird, insect, rodent, and plant populations.

Interview: Nils Zimmermann

http://www.dw.com/en/nuclear-accidents-make-mutant-bugs-and-birds/a-19098683?maca=en-Facebook-sharing

March 18, 2016 Posted by | Fukushima 2016 | , , , , , | Leave a comment