[ RadSafe ] Smithsonian - Low levels of radioactive cesium produced insect deformities at Fukushima

Tue May 20 09:21:13 CDT 2014

I know that insects are more radiation-resistant than we are - but I'm not sure how radiation-sensitive they are in the larval stage. So I made the assumption that they are more sensitive in this stage than in the adult stage - as we are. I guess the question I had was whether or not the amount of intake for the larvae is realistic or if they fed the critters an unreasonably high amount to try to force something to happen - like what happens in many studies of carcinogens. And as Brian (and others) mentioned, it's also worth asking if they fed stable CsCl to the control group, if both groups had the same diet overall, etc. I agree with you that it is interesting, but not yet compelling.

Andy

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Brad Keck
Sent: Monday, May 19, 2014 3:19 PM
To: The International Radiation Protection (Health Physics) Mailing List
Subject: Re: [ RadSafe ] Smithsonian - Low levels of radioactive cesium produced insect deformities at Fukushima

Hi Andy

One of the things I recall from many years ego as an undergrad ( and yes, I was one :) )  is that induction of effects in insects typically requires thousands of rad or tens of thousands of rad (back in the day, irradiating fruit flies was a big deal!).  This is one of many reasons I would say it is most unlikely that these authors have observed anything that is more likely to have resulted from the cesium decay than many other, routine and mundane factors- which are not even described, let alone considered.   

If they were to convince me that Only the  cesium differs, and there was enough dose to matter, and then  include many more experiments, I might have to reconsider, but on this basis, it is very inconsistent with a great deal of literature and great claims require great evidence! 

On the other hand, "the Daily Kos" finds this completely persuasive...   

Brad 

Sent from my iPad

> On May 19, 2014, at 9:40 AM, "KARAM, PHILIP" <PHILIP.KARAM at nypd.org> wrote:
> 
> It looks as though the article was really published in Nature - at least, I went to the Nature website and did a search under the author's name and came up with the paper. That being the case, I'm willing to give it a careful read rather than dismissing it out of hand. I'd also point out that, while it does cite some prominent people with somewhat dubious credentials, it also cites Warren Sinclair and Edward Calabrese - neither of whom can be accused of being anti-nuclear. 
> 
> The authors point out that the level of uptake they studied is 22 kBq per kg of body weight to cause abnormalities (0.76 Bq per larva)  - 0.6 uCi per kg for those of us still comfortable with the older units. For a 100 kg person (closer to "standard" in the US I'm afraid) this is a total body burden of 2.2 MBq (60 uCi).  This would give a whole-body dose on the order of a few tens of mSv (a few rem) if memory serves me.
> 
> In humans, there seems to be solid evidence that fetal doses of less than 50 mSv (5 rem) are not teratogenic; but I'm not sure what the data are for insects. I would imagine, however, that larvae are much more sensitive to radiation effects than are adult insects. The bottom line is that it seems plausible that feeding very high doses of Cs-137 to developing insects in their most radiation-sensitive stage might cause changes - the question then would seem to be whether or not these doses are plausible in real life (i.e. is equivalent to force-feeding rats the equivalent of hundreds of soft drinks worth of Nutrasweet daily) and whether or not they have any relevance to other creatures or to the ecosystem as a whole.
> 
> Finally, I'd note that our experience with Chernobyl suggests that ecosystems as we find them seem to be fairly resilient. Any laboratory experiments - however intriguing and illuminating - should at some point be able to explain what we actually see in the field.
> 
> 
> Andy
> 
> -----Original Message-----
> From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Roger Helbig
> Sent: Saturday, May 17, 2014 5:27 AM
> To: RADSAFE
> Subject: [ RadSafe ] Smithsonian - Low levels of radioactive cesium produced insect deformities at Fukushima
> 
> If this is not sound scientific research, the Smithsonian, a well
> respected popular magazine, should be informed.
> 
> Roger Helbig
> 
> Christina MacPherson posted: "New study reveals deaths and mutations
> "increased sharply' from exposure to Fukushima contamination,
> "especially at low doses" -- 'Small' levels of cesium may be
> 'significantly toxic' -- Smithsonian: "In other words, things don't
> look good for the animals l"
> 
> 
> New post on nuclear-news
> 
> Low levels of radioactive cesium produced insect deformities at Fukushima
> 
> by Christina MacPherson
> 
> New study reveals deaths and mutations "increased sharply' from
> exposure to Fukushima contamination, "especially at low doses" --
> 'Small' levels of cesium may be 'significantly toxic' -- Smithsonian:
> "In other words, things don't look good for the animals living around
> Fukushima" http://enenews.com/just-in-new-study-reveals-sharp-increase-in-deaths-and-mutations-from-exposure-to-fukushima-contamination-especially-at-low-doses-small-levels-of-cesium-may-be-significantly-toxic?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+ENENews+%28Energy+News%29
> 
> Smithsonian Magazine, May 14, 2014: Even Tiny Amounts of Radioactive
> Food Made Caterpillars Become Abnormal Butterflies [...] Researchers
> in Japan [...] discovered, even a small amount of radiation is too
> much. [...] The scientists collected plant material from around
> Fukushima and fed it to pale grass blue butterfly caterpillars. When
> the caterpillars turned into butterflies, they suffered from mutations
> and were more likely to die early [... even if they] had only eaten a
> small amount of artificial caesium [...] In other words, things don't
> look good for the animals living around Fukushima.
> 
> Nature -- Scientific Reports (pdf), Published May 15, 2014: [We]
> examined possible relationships between the dose of ingested cesium
> per larva and the mortality and abnormality rates. Both the mortality
> and abnormality rates increased sharply, especially at low doses [...]
> the mortality and abnormality rates increased sharply, especially at
> low doses. Additionally, there seemed to be no threshold level below
> which no biological response could be detected. [...] the
> dose-response data suggests that the relatively small level of
> artificial cesium from the Fukushima Dai-ichi NPP may be significantly
> toxic to some individuals in butterfly populations [...] the half
> lethal [i.e. LD50, amount that will kill 50% of a test subjects] dose
> [is 1.9 Bq per larva] and the half abnormal dose [is 0.76 Bq per
> larva] [...] relatively small [levels] of artificial cesium from the
> Fukushima Dai-ichi NPP may be significantly toxic to some individuals
> in butterfly populations [...] we assert that the half lethal and
> abnormal doses we obtained were quite high. [...] it should be noted
> that we sampled contaminated leaves from Fukushima City, which many
> people inhabit as though nothing had happened [...] Implications of
> the half lethal and abnormal doses we obtained in the present study
> will impact future discussions on the effects of radioactive exposure
> on other organisms, including humans. [...] In conclusion, it is
> important to recognize the risk of internal radiation exposure due to
> ingested radioactive cesium, at least for the pale grass blue
> butterfly, and likely for certain other organisms living in the
> polluted area, possibly including humans. [...]
> 
> View the study published by Nature here (pdf)
> 
> Christina MacPherson | May 17, 2014 at 7:32 am | Categories:
> environment, Japan, radiation, Reference | URL: http://wp.me/phgse-hlE
> 
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