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DNA Damage in Grasshoppers
#1
Tim Mousseau has new research results https://twitter.com/TimMousseau2

Just out in Physiological & Biochemical Zoology: latest findings from Chernobyl show DNA damage in grasshoppers is higher at shorter development times, irrespective of radiation | @ChicagoJournals http://www.journals.uchicago.edu/doi/pdf...086/696005
Pia
Jitsi chat: enfo.pia@gmail.com
 
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#2
(01-09-2018, 09:14 AM)piajensen Wrote: Tim Mousseau has new research results https://twitter.com/TimMousseau2

Just out in Physiological & Biochemical Zoology: latest findings from Chernobyl show DNA damage in grasshoppers is higher at shorter development times, irrespective of radiation | @ChicagoJournals http://www.journals.uchicago.edu/doi/pdf...086/696005

What does the Mousseau study mean?   Thats a huge range of radiation dose with little difference in DNA damage or longevity.  I was hoping to find what an average DNA damage rate is for non radiated grasshoppers is by the comet assay.  No control group!
 
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#3
Andrea Bonisoli said: "My latest findings from Chernobyl show DNA damage in grasshoppers is higher at shorter development times, irrespective of radiation" https://twitter.com/ABonisoli/status/950532251984396288

The abstract concludes with "Contrary to our hypothesis, parental exposure to radioactive contamination did not affect DNA damage in their offspring possibly because of intervening adaptation or parental compensatory mechanisms. Our results suggest a trade-off between developmental rate and resistance to DNA damage, whereby offspring developing at faster rates do so at the cost of damaging their DNA. This result is consistent with and extends findings in other species, suggesting that faster growth rates cause increased oxidative damage and stress. We propose that growth rates are subject to stabilizing selection balancing the benefits of fast development and the competing need of buffering its damaging effects to macromolecules and tissues."

Code: I think a more important question is: What correlations are there to primates exposed to nuclear radiation, if any, since these are a completely different species. Would be great if extensive research were done on primates affected by nuclear radiation.
Pia
Jitsi chat: enfo.pia@gmail.com
 
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#4
Pia, I read the study and reread the excerpt and I still don't get what the study is implying.  Was faster growth rate a result of radiation exposure?  What DNA damage were they looking for?  It seemed the study was saying that damage to DNA was not from radiation but only from a faster developmental rate affecting DNA.   Does the grasshopper life cycle afford some radiation resistance?   I have noticed that grasshoppers recovered faster than other insects in my backyard after 3-11.
"The map is not the territory that it is a map of ... the word is not the thing being referred to."
 
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#5
Pia, of course insects are the base of much of the ecosystem, and are arguably as valued in the grand cosmology as humans or other apes.  

My observations about the paper on grasshoppers; 

The radiation level was measured a centimeter above the soil. But the predominant radiation in soil is from potassium and this can vary significantly. For example in brazil K-40 varied from 540 to 3,500 bq/kg. (Average radiation in soil is U238 =30 bq/kg  Th232= 35 bq/kg and K40 =400 bq/kg).   Variations of K40 might be 100 to 1000 bq/kg. This grasshopper study made no attempt to differentiate the source radiation, although they assumed the gamma would correlate with fallout. ('We did not quantify the relative contribution of the different radionuclides to body burden of radiation in the exposed parents, nor did we quantify their respective abundance in the environment.')

Thus I can imagine natural variations of K-40 in soil and fission product variations could confound the study.  Different sources of radiation have different biological impacts, and especially important is the ingested fission products!  Mousseau should be on that!

They said they took the grasshoppers to a laboratory with low ambient radiation levels (0.06–0.12 mSv/h). That appears to be  almost 800 mSv/yr,   yet average background radiation is 3 mSv/yr.  I dont understand why the lab radiation level is hundreds of times higher than normal, or perhaps its a typo, or the way the radiation is measured.
Anyway, if its not a typo, the lab radiation was as high or higher than two of the Chernobyl collection areas.  That doesnt seem right

Then they kept the eggs in vermiculite for three months.  Probably they have this down to a science, but I see that a lot of vermiculite was contaminated with a kind of asbestos that has 10x the toxicity of normal asbestos. They could have gotten some of this vermiculite since the study was done in 2009. BTW, that seems like rather a long time ago to just be published now

 ('During the decades when Zonolite, a vermiculite insulation, was manufactured (1919 until 1990 but sold until around 2007), most of the world’s supply of vermiculite came from the town of Libby, Montana, which became so contaminated by asbestos that the U.S. Environmental Protection Agency (EPA) has now been working to clean the area up for almost 20 years. The Zonolite insulation distributed across the nation will haunt American homes for many more years to come. The kind of asbestos in contaminated vermiculite is 10 times more dangerous than the white asbestos used by most manufacturers')

Thats not the only problem with vermiculite. it also may contain U238 and Th232 at  131  and 117 bq/kg which is about 4x as high as average soils.  
http://jrpr.org/journal/view.php?doi=10....6.41.4.359
http://www.sciencedirect.com/science/art...6X16302341

Vermiculite can carry fission products. vermiculite is ubiquitous in aerosolic dusts carrying nuclear fission products in rainfall. Vermiculite fixes cesium and strontium  https://books.google.com/books?id=dIEOCo...um&f=false

Its use in rearing insects is extremely sensitive to the moisture and aeration. Vermiculite which is too wet or too dry will result in dead or defective pupae  (ideal 400 ml of water in 12000 ml of vermiculite.)  Dry vermiculite can cause 90% mortality while moist vermiculite in improperly vented enclosures causes increased metabolic rate, hypoxia and mortality. Hypoxia causes genetic damage.
 https://books.google.com/books?id=ncFDAQ...te&f=false

Their findings do not in fact correlate with other studies of low level fallout, as they point out;
' studies of the pale blue grass butterfly Zizeeria
maha in the area contaminated by the accident at the FukushimaDaiichi
nuclear power plant have discovered morphological abnormalities
that persist in both the F1 and F2 generations reared
under controlled lab conditions (Hiyama et al. 2012; Taira et al.
2014). Further, studies of human populations exposed to the aftermath
of the Chernobyl disaster have demonstrated increased
microsatellite mutation rates (Dubrova et al. 1996; Weinberg et al.
2001; Furitsu et al. 2005) and increased cellular abnormalities and
chromosomal breaks (Aghajanyan et al. 2011) in children born to
parents exposed to radiation after the Chernobyl accident'

For these reasons, any conclusions based on this research are highly speculative!

I looked for other examples of DNA damage based on the comet assay.  A healthy specimen may have much less than these +-40% levels. Very little 'tail' in the assay is observed.  Is that DNA damage normal for grasshoppers?  I kind of dont think so.  This could be an indication of hypoxic conditions while the eggs were in 3 month simulated wintering.  Half the nymphs died in these pristine conditions. Is that normal?

Many studies show gross deformities, reduced and sickened populations in fallout hit areas. Chernobyl, Fukushima and elsewhere.  The conclusions suggested by this paper seem to underrate the extraordinary ecological damage from Chernobyl.
 
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#6
one gets a different picture of harm to life from these other studies;

'The few genetic studies that have been conducted in Chernobyl generally show elevated rates of genetic damage and mutation rates. All major taxonomic groups investigated (i.e., birds, bees, butterflies, grasshoppers, dragonflies, spiders, mammals) displayed reduced population sizes in highly radioactive parts of the Chernobyl Exclusion Zone'
https://academic.oup.com/jhered/article/...04/2961808

'At Chernobyl and Fukushima, radioactivity has seriously harmed wildlife.' Timothy A. Mousseau
https://theconversation.com/at-chernobyl...life-57030

'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.
http://www.dw.com/en/scientists-fear-inc...a-16170549


'A series of articles summarizing these studies has now been published in the Journal of Heredity. These describe widespread impacts, ranging from population declines to genetic damage to responses by the repair mechanisms that help organisms cope with radiation exposure.'
'One of the studies (Hayashi et al. 2014) documented the effects of radiation on rice by exposing healthy seedlings to low-level gamma radiation at a contaminated site in Fukushima Prefecture. After three days, a number of effects were observed, including activation of genes involved in self-defense, ranging from DNA replication and repair to stress responses to cell death.'
https://phys.org/news/2014-08-biological...s.html#jCp
 
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#7
You raise a lot of good questions. I wasn't aware of the vermiculite situation and there is no discussion about it's source or whether it was tested for contaminants before and after "sterilizing." I wonder if they did the study today, would they be more thorough. I'll ask Tim if he could address your concerns. Thank you for providing additional studies.
Pia
Jitsi chat: enfo.pia@gmail.com
 
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#8
Hi All! It is nice to see that someone reads our papers!

This paper is much simpler than it seems, perhaps.

It is a simple test of whether or not irradiated parents have offspring with damaged DNA. In other words, if you take a parent, give it a good dose, a dose big enough to show damage to the individual receiving the dose, will this lead to evidence of genetic damage in their offspring?

This study shows rather convincingly for this one species of grasshopper, for one class of genetic damage markers, for a species that is still found in significant numbers in hot spots around Chernobyl, that the parental dose history is an insignificant contributor to genetic damage observed in the offspring.

Obviously, we were very surprised and a little disappointed with this finding as we had predicted that there should be some "ghost" of radiation past still showing in the offspring's DNA. But if there is, it was not detectable using our rather crude methods.

Our methods are quite crude and one might argue that using a cytogenetic approach (i.e. looking for breaks in the chromosomes) is a very narrow and not-so-sensitive way to get at this question. But it is the tool we had on hand. We figured it was worth looking since we have the tools and the grasshoppers. And, the general issue of inherited mutations (i.e. mutations in the germ line) is kind of an important topic.

Just by accident while conducting this study we detected a strong relationship between development rate and genetic damage. This finding really nicely illustrates the "live-fast-die-young" trade-off that dictates many life history relationships in the natural world. In fact, this relationship could be large enough that it swamped out any observable radiation effect. And to be honest, this is a result that may have very general ramifications for all critters everywhere.

There are several ways to take this study to the next step:

1) Use Advanced Genomics: We used the comet assay because someone donated a $150,000 robotic microscope to the lab that allowed us to perform these experiments in a timely manner. However, modern genomic approaches would be much more sensitive (and rigorous) and would allow us to look at actual "mutation" rates and changes in gene expression that might be associated with the parental radiation exposure. We are waiting for someone to give us $500,000 to get started with such an approach for bugs, birds, etc. Unfortunately, genetic research is very expensive in every domain (equipment, supplies, people to do the work) and so most folks in this field are studying diseases (e.g. cancer) in people, not radiation effects in grasshoppers!

2) Repeat this study in the field, and also expose offspring to radiation. In a perfect world, we would repeat this experiment but do it in "nature" (i.e. in Chernobyl) and also split the offspring into at least two groups that we irradiated or not. And of course we would use advanced genomics to maximize the sensitivity of the tests for genetic damage. But again, this would require hiring a couple full time people to live in Chernobyl and ruin the experiments.

3) Conduct this study in the laboratory and use controlled irradiation to better examine the relationship between dose and effect, and use advance genomics!

4) Repeat this study using a variety of different species to determine if perhaps the observe lack of effect is specific to this species or a general phenomenon.

We are trying to build along all these lines (i.e. advanced genomics, more experimental approaches, repeat with multiple species) and we are having some success especially with the use of small mammals (e.g. bank voles). It seems the Academy of Finland is much more open-minded about funding such research and several of our collaborators have been successful in finding the funding to continue our studies with the voles. Papers on this system are now starting to appear… Stay tuned!

(01-10-2018, 09:07 PM)Code Wrote: one gets a different picture of harm to life from these other studies;

'The few genetic studies that have been conducted in Chernobyl generally show elevated rates of genetic damage and mutation rates. All major taxonomic groups investigated (i.e., birds, bees, butterflies, grasshoppers, dragonflies, spiders, mammals) displayed reduced population sizes in highly radioactive parts of the Chernobyl Exclusion Zone'
https://academic.oup.com/jhered/article/...04/2961808

'At Chernobyl and Fukushima, radioactivity has seriously harmed wildlife.'   Timothy A. Mousseau
https://theconversation.com/at-chernobyl...life-57030

'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.
http://www.dw.com/en/scientists-fear-inc...a-16170549


'A series of articles summarizing these studies has now been published in the Journal of Heredity. These describe widespread impacts, ranging from population declines to genetic damage to responses by the repair mechanisms that help organisms cope with radiation exposure.'
'One of the studies (Hayashi et al. 2014) documented the effects of radiation on rice by exposing healthy seedlings to low-level gamma radiation at a contaminated site in Fukushima Prefecture. After three days, a number of effects were observed, including activation of genes involved in self-defense, ranging from DNA replication and repair to stress responses to cell death.'
https://phys.org/news/2014-08-biological...s.html#jCp

Perhaps Code did not notice that our team wrote several of the papers mentioned in this comment?
 
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#9
I feel much more educated now with Tim's clarifications and I do hope his team receives the funding needed for genomic research. That does sound like the key to greater understanding.

Two questions, Tim -  when you say "this is a result [live-fast-die-young] that may have very general ramifications for all critters everywhere." Does that also include primates? Thinking it must. So, we, humans, would have shorter life expectations, as we see with Chernobyl's human offspring?
Pia
Jitsi chat: enfo.pia@gmail.com
 
Reply
#10
(01-09-2018, 08:06 PM)Code Wrote:
(01-09-2018, 09:14 AM)piajensen Wrote: Tim Mousseau has new research results https://twitter.com/TimMousseau2

Just out in Physiological & Biochemical Zoology: latest findings from Chernobyl show DNA damage in grasshoppers is higher at shorter development times, irrespective of radiation | @ChicagoJournals http://www.journals.uchicago.edu/doi/pdf...086/696005

What does the Mousseau study mean?   Thats a huge range of radiation dose with little difference in DNA damage or longevity.  I was hoping to find what an average DNA damage rate is for non radiated grasshoppers is by the comet assay.  No control group!
Yes, there are controls. Both "clean" and contaminated areas (along a gradient) were used so that a dose-response relationship might be observed, but now [none?] was seen. But I agree that studying more populations from more distant areas would be a good idea. That said the results here are pretty clear. More control populations would be especially helpful if a positive effect had been observed.

(01-10-2018, 03:09 PM)Code Wrote: Pia, of course insects are the base of much of the ecosystem, and are arguably as valued in the grand cosmology as humans or other apes.  

My observations about the paper on grasshoppers; 

The radiation level was measured a centimeter above the soil. But the predominant radiation in soil is from potassium and this can vary significantly. For example in brazil K-40 varied from 540 to 3,500 bq/kg. (Average radiation in soil is U238 =30 bq/kg  Th232= 35 bq/kg and K40 =400 bq/kg).   Variations of K40 might be 100 to 1000 bq/kg. This grasshopper study made no attempt to differentiate the source radiation, although they assumed the gamma would correlate with fallout. ('We did not quantify the relative contribution of the different radionuclides to body burden of radiation in the exposed parents, nor did we quantify their respective abundance in the environment.')

Thus I can imagine natural variations of K-40 in soil and fission product variations could confound the study.  Different sources of radiation have different biological impacts, and especially important is the ingested fission products!  Mousseau should be on that!

YES, IT WOULD HAVE BEEN GREAT TO BETTER CHARACTERIZE THE TYPES OF CONTAMINANTS. UNFORTUNATELY, WE DID NOT HAVE THE RESOURCES FOR THIS.  AS A RESULT WE CAN ONLY REPORT ON  THE COMBINED EFFECTS, AS MEASURED BY OUR AMBIENT RADIATION READINGS (COMBINED ALPHA + BETA + GAMMA). 

They said they took the grasshoppers to a laboratory with low ambient radiation levels (0.06–0.12 mSv/h). That appears to be  almost 800 mSv/yr,   yet average background radiation is 3 mSv/yr.  I dont understand why the lab radiation level is hundreds of times higher than normal, or perhaps its a typo, or the way the radiation is measured.
Anyway, if its not a typo, the lab radiation was as high or higher than two of the Chernobyl collection areas.  That doesnt seem right

CODE MISREAD - IT WAS 0.06 - 0.12 MICROSIEVERTS I.E. LESS THAN 1 MILLISIEVERT PER YEAR. HERE IS THE LINE FROM THE METHODS SECTION:


I THINK PERHAPS THE MICROSYMBOL GETS MESSED UP WHEN COPYING AND PASTING....

Then they kept the eggs in vermiculite for three months.  Probably they have this down to a science, but I see that a lot of vermiculite was contaminated with a kind of asbestos that has 10x the toxicity of normal asbestos. They could have gotten some of this vermiculite since the study was done in 2009. BTW, that seems like rather a long time ago to just be published now

 ('During the decades when Zonolite, a vermiculite insulation, was manufactured (1919 until 1990 but sold until around 2007), most of the world’s supply of vermiculite came from the town of Libby, Montana, which became so contaminated by asbestos that the U.S. Environmental Protection Agency (EPA) has now been working to clean the area up for almost 20 years. The Zonolite insulation distributed across the nation will haunt American homes for many more years to come. The kind of asbestos in contaminated vermiculite is 10 times more dangerous than the white asbestos used by most manufacturers')

Thats not the only problem with vermiculite. it also may contain U238 and Th232 at  131  and 117 bq/kg which is about 4x as high as average soils.  
http://jrpr.org/journal/view.php?doi=10....6.41.4.359
http://www.sciencedirect.com/science/art...6X16302341

Vermiculite can carry fission products. vermiculite is ubiquitous in aerosolic dusts carrying nuclear fission products in rainfall. Vermiculite fixes cesium and strontium  https://books.google.com/books?id=dIEOCo...um&f=false

Its use in rearing insects is extremely sensitive to the moisture and aeration. Vermiculite which is too wet or too dry will result in dead or defective pupae  (ideal 400 ml of water in 12000 ml of vermiculite.)  Dry vermiculite can cause 90% mortality while moist vermiculite in improperly vented enclosures causes increased metabolic rate, hypoxia and mortality. Hypoxia causes genetic damage.
 https://books.google.com/books?id=ncFDAQ...te&f=false

SINCE ALL HOPPERS AND THEIR EGGS WERE TREATED THE SAME WAY ANY BIAS DUE TO THE VERMICULITE WOULD HAVE BEEN SYSTEMATIC ACROSS ALL INDIVIDUALS. BUT CERTAINLY THIS IS WORTH LOOKING AT IN MORE DETAIL.


Their findings do not in fact correlate with other studies of low level fallout, as they point out;
' studies of the pale blue grass butterfly Zizeeria
maha in the area contaminated by the accident at the FukushimaDaiichi
nuclear power plant have discovered morphological abnormalities
that persist in both the F1 and F2 generations reared
under controlled lab conditions (Hiyama et al. 2012; Taira et al.
2014). Further, studies of human populations exposed to the aftermath
of the Chernobyl disaster have demonstrated increased
microsatellite mutation rates (Dubrova et al. 1996; Weinberg et al.
2001; Furitsu et al. 2005) and increased cellular abnormalities and
chromosomal breaks (Aghajanyan et al. 2011) in children born to
parents exposed to radiation after the Chernobyl accident'

CHERNOBYL AND FUKUSHIMA ARE DIFFERENT IN THAT OTAKI'S GROUP STUDIED THE BUTTERFLIES IMMEDIATELY AFTER THE DISASTER (I.E. ACUTE EFFECTS) AND DOSES TO THE INITIAL GROUP WERE LIKELY MUCH HIGHER THAN THE CHRONIC EXPOSURES SEEN IN CHERNOBYL AFTER MANY YEARS.


For these reasons, any conclusions based on this research are highly speculative!

I looked for other examples of DNA damage based on the comet assay.  A healthy specimen may have much less than these +-40% levels. Very little 'tail' in the assay is observed.  Is that DNA damage normal for grasshoppers?  I kind of dont think so.  This could be an indication of hypoxic conditions while the eggs were in 3 month simulated wintering.  Half the nymphs died in these pristine conditions. Is that normal?

WE TWEAKED THE COMET ASSAY AS MUCH AS POSSIBLE TO INCREASE THE SENSITIVITY OF THE ASSAY HENCE THE RATHER HIGH BACKGROUND DAMAGE LEVELS. WITHOUT TWEAKING, DAMAGE LEVELS WOULD BE VERY LOW AND PERHAPS TOO LOW TO DETECT ANY EFFECTS. WE HAVE CONDCUTED COMET ASSAYS ON MANY DIFFERENT SYSTEMS INCLUDING OTHER INSECTS AND MANY MANY BIRDS SPECIES. See:
https://www.researchgate.net/publication...s_in_birds


Many studies show gross deformities, reduced and sickened populations in fallout hit areas. Chernobyl, Fukushima and elsewhere.  The conclusions suggested by this paper seem to underrate the extraordinary ecological damage from Chernobyl.

YES THIS IS TRUE. OUR GROUP HAS WRITTEN MANY OF THESER PAPERS! BUT THE DIFFERENCE IS THAT WE COULD NOT TELL FROM SIMPLE OBSERVATIONS WHETHER THE 'MUTANTS' WERE THE RESULT OF DIRECT GENETIC DAMAGE TO THE INDIVIDUAL DURING DEVELOPMENT OR THE RSULT OF INHERITED MUTATIONS. THE GRASSHOPPER PAPER IS ONE OF ONLY A FEW STUDIES THAT ATTEMPTS TO DIFFERENTIATE BETWEEN THESE TWO POSSIBLE SOURCES OF GENETICALLY BASED ABNORMALITIES.

(01-11-2018, 10:05 AM)piajensen Wrote: I feel much more educated now with Tim's clarifications and I do hope his team receives the funding needed for genomic research. That does sound like the key to greater understanding.

Two questions, Tim -  when you say "this is a result [live-fast-die-young] that may have very general ramifications for all critters everywhere." Does that also include primates? Thinking it must. So, we, humans, would have shorter life expectations, as we see with Chernobyl's human offspring?

HI Pia,

Yes, I think it is generally recognized that genetic damage incurred early in life can lead to shortened life spans. I think there is a large literature on this subject. And certainly this also applies to primates.
 
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#11
Professor Mousseau!  

Its such a privilege to have you touch down in this forum and clarify the mysteries with your expertise.  I hope you continue to visit, as time might permit.   With an ever growing stockpile of nuclear waste and ongoing threat of nuclear warfare, understanding -and educating the world- about the biological effects of nuclear fallout is crucial to avoid inflicting immense suffering to life on earth. 

Thank you for your responses on the grasshopper paper.  You and your group seem to be one of the few in the west that are bringing to light the damage done by anthropogenic radiation, thus highly appreciated by those who have concerns.

I did indeed realize you authored many of the studies which elucidate fallout effects, and tease apart the complex ecological interactions.  The study on the bird trap effect in Chernobyl for example is a Sherlock Holmes exposé  much needed in a media milieu that rejoices in Chernobyl as a thriving eco-haven. 

There is a great weight from the radiation health risk science community which holds down...I would say nearly obliterates the dissenting concerns of the anti nuclear community.  We have gone from the deterrent of 'mutual assured destruction' in the cold war era to  a casual consideration of preemptive nuclear bombing of Iran and N Korea. 

From my view, a lot of this hinges not only on the ICRP dose model, which Busby et al have shown is in stark disagreement with epidemiological studies from Chernobyl, but also a ubiquitous mistaken concept of the nature of ionizing radiation. The whole of the electromagnetic spectrum above UV is lumped into one generalized idea of biological effect, and inevitably compared to the background radiation which in most cases is larger than fallout.  There is the assumption that nuclear power plants and low level fallout cant possibly cause significant harm. For example, the World Nuclear Association says



"The main effect of low-level radiation arises from fear, not the radiation itself.  Sometimes the fear is promoted by misguided governments, as in Japan where maintaining the evacuation of many people beyond a few weeks has resulted in over 1000 deaths, though exposure levels if people had returned to homes would not be hazardous except possibly in some limited areas, easily defined."


http://www.world-nuclear.org/information...fects.aspx

Thus, understanding the differences in biological effect  could be the crux of overturning the mistaken assumption that all radiation sources are the same.  (differences WITHIN the categories of alpha, beta, gamma etc).  This is why I was so keen on differentiating Cs from K40 for example, in your grasshopper study.

'We have also been investigating high-LET-radiation induced bystander effects using the heavy-ion microbeams at Takasaki Ion Accelerators for Advanced Radiation Application in Japan Atomic Energy Agency. Only 0.04% of the total numbers of normal human fibroblasts were irradiated with C-ion (220 MeV), Ne-ion (260 MeV) and Ar-ion (460 MeV) microbeams collimated at 20 μm in diameter. Cell-killing effect and gene mutation at HPRT locus in the cells irradiated with C ions were higher beyond our expectations and returned the estimated values that only 0.04% of the total cells were irradiated when using the specific inhibitor of gap junctions. On the other hand, no induced biological effects were observed in Ne and Ar ions whether the inhibitor was applied or not. The result suggested that the C-ion microbeam was capable of inducing bystander cellular effects via gap junction-mediated cell-cell communication. There is clear evidence that bystander cellular effects are dependent on radiation quality.'
Radiation-quality-dependent bystander effects induced by the microbeams with different radiation sources
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3941530/
 
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#12
Awesome and informative replies above... it certainly is an honor to have one of the very few radiation researchers among us. I much appreciate learning more about your research methods and also hearing from voices questioning the meaning of it all. And, yet... tears spring forth because I understand that what I felt before this additional knowledge is, in fact, true.

I don't like crying so it isn't that I'm bawling my eyes out, but the sense that we have come to a very certain crossroads (with the safest route being almost entirely obscured) weighs heavily. I am so glad I never had children,this makes it easier for me to absorb.

This dialog is inspirational and I hope that medical professionals will take note.
Pia
Jitsi chat: enfo.pia@gmail.com
 
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