Death toll from radiation exposure wrt. Chernobyl?

  • #1
Hi, I've been trying to de-misinform myself about the Chernobyl disaster in relation to radiation exposure.

I found this study on the WHO website that states,

Bennett continued: “This was a very serious accident with major health consequences, especially for thousands of workers exposed in the early days who received very high radiation doses, and for the thousands more stricken with thyroid cancer. By and large, however, we have not found profound negative health impacts to the rest of the population in surrounding areas, nor have we found widespread contamination that would continue to pose a substantial threat to human health, within a few exceptional, restricted areas.”
Main points I would like to bring up:

About 4000 cases of thyroid cancer, mainly in children and adolescents at the time of the accident, have resulted from the accident’s contamination and at least nine children died of thyroid cancer; however the survival rate among such cancer victims, judging from experience in Belarus, has been almost 99%.
Persistent myths and misperceptions about the threat of radiation have resulted in “paralyzing fatalism” among residents of affected areas.
He explains that there have been 4000 cases of thyroid cancer, mainly in children, but that except for nine deaths, all of them have recovered. "Otherwise, the team of international experts found no evidence for any increases in the incidence of leukemia and cancer among affected residents."
The international experts have estimated that radiation could cause up to about 4000 eventual deaths among the higher-exposed Chernobyl populations, i.e., emergency workers from 1986-1987, evacuees and residents of the most contaminated areas. This number contains both the known radiation-induced cancer and leukaemia deaths and a statistical prediction, based on estimates of the radiation doses received by these populations. As about quarter of people die from spontaneous cancer not caused by Chernobyl radiation, the radiation-induced increase of only about 3% will be difficult to observe.
Source.

Now, it seems that the source of my confusion is due to some apparent shortcomings in my knowledge about how much radiation were people actually exposed to, how much persistent ambient levels of relatively high levels of radiation can an organism cope with, and obviously the hyperbole about the threat of radiation exposure to human beings propagated through the media.

If anyone would care to point me to any appropriate source in regards to the above, thanks.
 

Answers and Replies

  • #2
russ_watters
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It isn't really clear to me what your question is. Are you just expressing surprise that the death toll was lower than you previously believed?
 
  • #3
It isn't really clear to me what your question is. Are you just expressing surprise that the death toll was lower than you previously believed?
I'm interested as to why the death toll is so "low". Hence, my question about tolerance to radiation exposure over time and such at the end of my OP, and other factors that could contribute to the given findings by the WHO report.

Edit: Here is something along the lines at which I am getting at with my various ill-phrased questions:

https://atomicinsights.com/evidence...igher-radiation-doses-than-governments-allow/

Edit #2: An even better-qualified explication of "radiation hormesis", which I seem to be beating around the bush at:

https://www.reddit.com/r/askscience...le_to_build_a_tolerance_to_radiation/cgfbrzo/
 
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  • #4
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Natural background radiation varies from ~1 mSv/year to ~5 mSv/year, with some outliers (some people in Ramsar in Iran receive tens of mSv/year). No link between different levels of background radiation and cancer rates was found.
Cancer Mortality Among People Living in Areas With Various Levels of Natural Background Radiation

We know high doses of radiation lead to higher risk of cancer and very high doses lead to negative short-term effects (including death), but apart from workers at the power plant basically no one received doses at this level. We don't know if low radiation levels lead to increased cancer risks (with some exceptions that rarely lead to deaths). Some researchers even speculate that they could lower the risk of cancer.

Radiation levels in many parts of the exclusion zone today are lower than in Ramsar. While people live in Ramsar, don't bet that the exclusion zone is made smaller anytime soon.
 
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  • #5
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I'm interested as to why the death toll is so "low".
Right now this question is hard to be discussed without environmental politics involved.

The point is, that the expected harm caused by radiation is usually calculated on basis of the so called 'Linear No Threshold' model. But already quite amount of scientific data suggests that this model should not be used without limitations, especially when it's about low doses. (Google "LNT controversy")
Even so, there is no alternative to be used (partially, because due the above mentioned political involvement the relevant researches tends to get only limited resources).
Also, usually the closer you search to the 'public opinion' the less you will hear about the limits of the model.

So your confusion is quite normal, actually. The numbers tends to shrink (or disappear entirely) when your scope of interest shifts from the area of 'public knowledge' to 'actual statistics'.
 
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  • #6
Yeah, I won't pursue the matter if talk for or against the LNT model is prohibited.
 
  • #7
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As far as I know it's not actually prohibited. It's just by my experiences it often ends in intensive (green) politics and hard to keep it science based.
 
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  • #8
russ_watters
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I'm interested as to why the death toll is so "low".
Well again, "So low" implies it could have, should have or was expected to be much worse. So the real question is, why is there this expectations/perceptions gap? And I'm not picking on you; this is a serious problem across the majority of people in western society.

The short answer is that it is due to a complex interaction of media, government, activism and fear of the unknown. I'm glad you asked for numbers and facts though, because knowledge is the best way to fight warped perceptions. Mfb provided some and I can give more when I get more time later, but one interesting factoid:

Fukushima had three meltdowns, which together released about a tenth as much radioactive material as Chernobyl. The surrounding 20km radius area is still evacuated today. So here's the punchline: By the standard under which Fukushima remains evacuated, we should permanently abandon Denver, which has higher natural background radiation than the accident induced plus background radiation at Fukushima.

Crazy, right? I think the same is true of most of the Chernobyl area, but I'm not certain.
 
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  • #9
russ_watters
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The point is, that the expected harm caused by radiation is usually calculated on basis of the so called 'Linear No Threshold' model. But already quite amount of scientific data suggests that this model should not be used without limitations, especially when it's about low doses. (Google "LNT controversy")
Even so, there is no alternative to be used (partially, because due the above mentioned political involvement the relevant researches tends to get only limited resources).
That's how cancer risks are calculated from a certain radiation level, but what is the baseline for determining risk associated with the event? My understanding is that it is local background radiation, not a "generally safe" (or safe enough) threshold, which is what produces the prediction that an accident could be causing cancer while a higher background radiation somewhere else is ignored. That, to me, is the real problem. I'm actually mostly ok with the LNT because there actually *is* a threshold applied at the end; just not a good one.

A similar risk analysis issue exists with self driving cars, and it's a legal issue as much as anything: though safer overall, self driving cars cause specific, different types of accidents than normal cars. As such, if you are injured in such a crash you can still sue.
 
  • #10
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Yeah, I won't pursue the matter if talk for or against the LNT model is prohibited.
As with many politically charged issues on PF, if we stick to analyzing it scientifically, we're fine.
 
  • #11
jim mcnamara
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Moved to Biology
 
  • #12
StoneTemplePython
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Fukushima had three meltdowns, which together released about a tenth as much radioactive material as Chernobyl. The surrounding 20km radius area is still evacuated today. So here's the punchline: By the standard under which Fukushima remains evacuated, we should permanently abandon Denver, which has higher natural background radiation than the accident induced plus background radiation at Fukushima.
Do you have supporting materials / suggested reading here? There are lot's of kinds of radiation. I think you're getting at cosmic rays in Denver here. I'm not sure about comparing to plutonium and uranium.

A thoughtful piece on Fukushima from a Bayesian knight, who probably does the best job out there on explaining health risks:
http://www.bbc.com/news/world-asia-pacific-12785274

- - - -
Btw, people should be very concerned about CT scans.

edit: Spiegelhlater actually covered this as well in the above linked article! I hadn't realized that.
 
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  • #13
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I just want to touch upon what the folks here said.

Ii think it would be a bit unfair from a scientific point of view to compare places of higher background radiation like Ramsar or Denver for that matter to Chernobyl or Fukushima, and 'm sure most of you here know why that is, well for those who don't let me put it out here, because of different sources of radiation,
and sure I agree a bit higher background of say ionizing EM radiation doesn't do any harm, but if that radiation is coming from lots of widely dispersed miniature activated nuclear fuel particles, that undergo their half life decays, like in the forests of Chernobyl then that is a bit different than having monazite sands which are naturally radioactive because contains Uranium and Thorium in them.
The difference is these sands have nowhere near Uranium in them to achieve critical mass so no fission and if no fission then no activation products that have half lives,
note that fresh unused fuel in nuclear reactors is also handled without any shielding because it's radioactivity is low.

the risk in cases like Chernobyl to my understanding is not the level of radioactivity you get if you stand next to the reactor sarcophagus dressed in a polyethylene bag , the danger is because the territory is littered still with millions of small particles that escaped the reactor and even though most of them are absorbed itno grass and ground by now the place is still off limits because wherever there are people living there will be children and noone can safeguard them when they go into forests and dig holes and then put their fingers in mouth.
But otherwise I agree from a purely visiting or walking in a sunny day perspective Chernobyl is fine,



As for why the westerners are so afraid from radioactivity unlike the folks in Russia or China or elsewhere in the east I think it is because as Russ already pointed out (I think ti was russ, not sure) in USA for example there is ofcourse competent government agencies where people work and they know what they do but they don't make the headlines usually, the headlines are made by the millions of activists , social justice warriors , leftists and rightwingers and greenpeace advocates and all the other folks who make their living by lobbying interests or simply talking about matters they don't know fully, and the problem is that most of these people really don't know their own subject that well especially if it's a science based and complicated one, but they don't need to because they are making good living off of their uninfomed opinion.
take youtube for example, sure if you already know science and want to learn more and have a strong capability to know whether the source is trustworthy then it can help you in finding good info, but imagine your a random average searcher and you stumble upon "pewdiepie" or someone else talking about matters they have literally no background in, then that's another story.

In places like Russia they have felt the other side of the road, their public opinion was next to zero for a long time and now it's a bit over zero, so the society has very little say in many issues, so in places like nuclear reactors and science maybe it;'s a good thing because honestly what does the average working man know about such stuff, not much, maybe it's not so good when your opinion is similarly discarded in matters like where your children will learn or other stuff...


Made a bit of a long post but hopefully the OP learned something from this.
 
  • #14
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oh , btw,


https://en.wikipedia.org/wiki/Monazite

read and watch these and then google what types of radiation these sands give off and maybe you can tell us whether you think it is dangerous or not, even though I believe the video already gives that answer
 
  • #15
russ_watters
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Do you have supporting materials / suggested reading here?
Yes, it's from the book "Energy for Future Presidents". I can provide specific quotes/data when I get home tonight.
There are lot's of kinds of radiation. I think you're getting at cosmic rays in Denver here. I'm not sure about comparing to plutonium and uranium.
It actually did say it was due to natural uranium, not cosmic rays. Probably the geological activity of the Rockies brings it up.
A thoughtful piece on Fukushima from a Bayesian knight, who probably does the best job out there on explaining health risks:
http://www.bbc.com/news/world-asia-pacific-12785274
That's a really good article. It is rare to get that perspective from the media.
Btw, people should be very concerned about CT scans.
Agreed, but at least in that case there is a harm prevention to balance the risk against.
 
  • #16
StoneTemplePython
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I may check out that book.

That's a really good article. It is rare to get that perspective from the media.
Sir David Spiegelhalter used to maintain his blog but it's been a while... he does have a good twitter feed. He actually comments a lot on there about the media messing things up and he valiantly tries to correct them. He's also my favorite guest correspondent on "More or Less" podcast (about correcting stats in the media). A lot of this stuff has a very British flare though.

Agreed, but at least in that case there is a harm prevention to balance the risk against.
Spiegelhalter (and Gigerenzer) both spend a lot of time talking about diagnostic tests that cause more harm than good. It's a subtle area -- some tests for certain demographics are worth doing... but beyond that it gets tricky as it involves probabilistic subtlety and typically a lot of emotions. CT scans have some role, but people justifiably should be suspicious of them. Put differently, a lot of preventative screenings don't prevent anything. Maybe a different thread though.
 
  • #17
russ_watters
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I may check out that book.
I highly recommend it. It was published in 2012 and Section 1 is titled "Energy Catastrophes". The goal of the section is to put the risk in proper context. Chapter 1 is Fukushima.

There are a lot of numbers, but one scenario the author ran is this scenario for the accident itself:
22,000 people lived within 30km of Fukushima. The highest dose recorded in that area was 22 rem. Assuming everyone in that zone received it, and using 25 rem = 1% lifetime odds of getting cancer yields 194 excess cases of cancer (the normal lifetime odds is 20%).

More:
  • Typical global average background is 0.3 rem/yr and typical average medical dose is another 0.3 rem/yr for a lifetime dose of about 48 rem.
  • Denver has an average background of 0.6 rem/yr, or 0.3 rem/yr above the global average (note: Denver's cancer rate is lower than the national average) .
  • The Chernobyl exclusion zone has an evacuation threshold of 0.1 rem/yr excess (the wording is a bit odd; I don't think that's the actual excess but rather the threshold for continuing the evacuation or re-population). This is based on guidance from the International Commission on Radiological Protection. Note: I mis-remembered this as Fukushima, but haven't edited my previous post because it is quoted. Sorry for the error. The thresholds for Fukushima were indeed set higher, though this number was cited in the media as a possible reason to lower it (or even evacuate Tokyo, where several "hot spots" exceeding it were detected).
  • Most of the Fukushima region inside the evacuation zone received a dose of less than 0.5 rem over the first year.
  • Since the book was just published in 2012 it doesn't have "current" exposure rates. But HERE is a source with some readings, including a particular town 23 miles north of the plant, with an annual dose rate of 3 mSv/yr (0.3 rem) and by the wording I believe that's total; ambient + accident.
Note: I don't necessarily think the Chernobyl zone should be re-populated. Due to the explosion and lack of containment dome, chunks of radioactive material were flung miles away and it is conceivable that small bits that are quite harmful are laying in the ground nearby. This would have to be investigated in detail and abated before full re-population.
 
  • #18
StoneTemplePython
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I highly recommend it. It was published in 2012 and Section 1 is titled "Energy Catastrophes". The goal of the section is to put the risk in proper context. Chapter 1 is Fukushima.

There are a lot of numbers, but one scenario the author ran is this scenario for the accident itself:
22,000 people lived within 30km of Fukushima. The highest dose recorded in that area was 22 rem. Assuming everyone in that zone received it, and using 25 rem = 1% lifetime odds of getting cancer yields 194 excess cases of cancer (the normal lifetime odds is 20%).

More:
  • Typical global average background is 0.3 rem/yr and typical average medical dose is another 0.3 rem/yr for a lifetime dose of about 48 rem.
  • Denver has an average background of 0.6 rem/yr, or 0.3 rem/yr above the global average (note: Denver's cancer rate is lower than the national average) .
  • The Chernobyl exclusion zone has an evacuation threshold of 0.1 rem/yr excess (the wording is a bit odd; I don't think that's the actual excess but rather the threshold for continuing the evacuation or re-population). This is based on guidance from the International Commission on Radiological Protection. Note: I mis-remembered this as Fukushima, but haven't edited my previous post because it is quoted. Sorry for the error. The thresholds for Fukushima were indeed set higher, though this number was cited in the media as a possible reason to lower it (or even evacuate Tokyo, where several "hot spots" exceeding it were detected).
  • Most of the Fukushima region inside the evacuation zone received a dose of less than 0.5 rem over the first year.
  • Since the book was just published in 2012 it doesn't have "current" exposure rates. But HERE is a source with some readings, including a particular town 23 miles north of the plant, with an annual dose rate of 3 mSv/yr (0.3 rem) and by the wording I believe that's total; ambient + accident.
This seems kind of low? The highest numbers I'm seeing are 6msv or so? One CT scan has 15 msv for an adult and 30 msv for a newborn. At least the variance of this is probably tightly bounded with CT scans.

Note: I don't necessarily think the Chernobyl zone should be re-populated. Due to the explosion and lack of containment dome, chunks of radioactive material were flung miles away and it is conceivable that small bits that are quite harmful are laying in the ground nearby. This would have to be investigated in detail and abated before full re-population.
Yea, I suspect there is a negative convex response biologically in terms of increased exposure and mortality (with a domain of some 'materially bad threshold' to a threshold where you die with extremely high chances), and combining this with significant variance in the underlying radiation, it seems foolish to 'price out and sell' a potentially very negative option purely on average numbers. But, I don't think many people (or large central planning bureaucracies) really understand convexity -- so maybe having some paranoia around radiation polluted areas is a semi-ok offset.
 
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  • #19
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Ii think it would be a bit unfair from a scientific point of view to compare places of higher background radiation like Ramsar or Denver for that matter to Chernobyl or Fukushima, and 'm sure most of you here know why that is, well for those who don't let me put it out here, because of different sources of radiation,
This is taken into account in the calculations. It is the reason we use mSv (or rem=10mSv) instead of Bq/m3 in this thread. Sv is designed to be comparable.
 
  • #20
russ_watters
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This seems kind of low? The highest numbers I'm seeing are 6msv or so? One CT scan has 15 msv for an adult and 30 msv for a newborn. At least the variance of this is probably tightly bounded with CT scans.
Which part seems low? Here's a link that confirms the average background for the USA is 3.1 msv/yr:
https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/bio-effects-radiation.html

According to your link, there are 70 million CT scans per year in the US. With a population of 320 million and using your value of 15, that's an average dose of 3.2 msv/yr. But that value looks high to me. This link says the typical effective does is from 1-10, with a max of 16:
https://www.fda.gov/Radiation-Emitt...es/MedicalImaging/MedicalX-Rays/ucm115329.htm

So I think you are high, but either way we are in the ballpark.
 
  • #21
Well again, "So low" implies it could have, should have or was expected to be much worse. So the real question is, why is there this expectations/perceptions gap? And I'm not picking on you; this is a serious problem across the majority of people in western society.
Well, trying to align this with respect to the LNT model, since we can talk about that, and it doesn't seem the LNT model is representative of the facts that have been presented in the OP or by others members in regards to higher ambient levels of radiation and the risk for having cancer.

Fukushima had three meltdowns, which together released about a tenth as much radioactive material as Chernobyl. The surrounding 20km radius area is still evacuated today. So here's the punchline: By the standard under which Fukushima remains evacuated, we should permanently abandon Denver, which has higher natural background radiation than the accident induced plus background radiation at Fukushima.

Crazy, right? I think the same is true of most of the Chernobyl area, but I'm not certain.
Yeah, I have nothing to add in regards to that. Could this distortion be attributed to thinking of the risk of having cancer in terms of the LNT model, from a regulatory perspective?

Edit: In order to answer my question, I would be interested in a prediction of deaths from events such Chernobyl according to the LNT model and compare it with the actual real world facts.
 
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  • #22
StoneTemplePython
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Which part seems low? Here's a link that confirms the average background for the USA is 3.1 msv/yr:
https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/bio-effects-radiation.html

According to your link, there are 70 million CT scans per year in the US. With a population of 320 million and using your value of 15, that's an average dose of 3.2 msv/yr. But that value looks high to me. This link says the typical effective does is from 1-10, with a max of 16:
https://www.fda.gov/Radiation-Emitt...es/MedicalImaging/MedicalX-Rays/ucm115329.htm

So I think you are high, but either way we are in the ballpark.
hmmm -- in an earlier posting I had an excerpt from Gigerenzer saying in the range of 15 mSv adult to 30 mSv (infant) dosage per CT scan. I edited it and deleted it as I thought Spiegelhalter covered the gist. (With your moderator powers you may be able to see the pre-editted posting?) He has a qualifier of "depending on machine settings and the organ studied" so hmm...

What I meant to say was if we use CT scans as a ruler, the radiation quotes in your post from Chernobyl and Fukushima don't look that big / seem kind of low. Whether that says more about the meltdowns or the ruler, I leave to you.


According to your link, there are 70 million CT scans per year in the US. With a population of 320 million and using your value of 15, that's an average dose of 3.2 msv/yr.
Very nice back of the envelope check here. (I thought the 70 million was ambiguous in the Spiegelhalter writeup as it jumped back and forth between uk, us and global -- but the same 70MM is in Gigerenzer and is clearly US.)
 
  • #23
russ_watters
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Well, trying to align this with respect to the LNT model, since we can talk about that, and it doesn't seem the LNT model is representative of the facts that have been presented in the OP or by others members in regards to higher ambient levels of radiation and the risk for having cancer.

Yeah, I have nothing to add in regards to that. Could this distortion be attributed to thinking of the risk of having cancer in terms of the LNT model, from a regulatory perspective?

Edit: In order to answer my question, I would be interested in a prediction of deaths from events such Chernobyl according to the LNT model and compare it with the actual real world facts.
Well, this can certainly be answered with some googling. I'm going to bed now, but maybe you could do some...
 
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  • #24
russ_watters
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hmmm -- in an earlier posting I had an excerpt from Gigerenzer saying in the range of 15 mSv adult to 30 mSv (infant) dosage per CT scan. I edited it and deleted it as I thought Spiegelhalter covered the gist. (With your moderator powers you may be able to see the pre-editted posting?) He has a qualifier of "depending on machine settings and the organ studied" so hmm...
The wording implies average, but the caveat implies not. I think the caveat points to the real average being lower and more in line with what I saw. Here's another link that agrees with the lower number (only 1 of 5 scan types has an upper limit of 15; all the rest, the entire ranges are lower):
https://med.stanford.edu/content/da...eischmann_RadiationDoseRisk_final_HANDOUT.pdf
 
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  • #25
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Yeah, I have nothing to add in regards to that. Could this distortion be attributed to thinking of the risk of having cancer in terms of the LNT model, from a regulatory perspective?
The LNT is very conservative, but exclusion zones are even more conservative than that.
They are not chosen based on scientific estimates of risks. They are chosen based on the population fearing something they don't understand. They don't understand that Denver has a higher background radiation either, but that doesn't make it into the news so no one fears it. If Denver would have a nuclear accident nearby people would fear that, no matter how small the released radiation is.
 

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