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

[KARAM, PHILIP]

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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