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It seems plausible that increased radiation exposure could negatively impact the health of these populations.

  • cancer patients currently on a chemoradiation regime
  • cancer survivors who are at-risk from radiation exposure
  • those with cancer risk, which may be at-risk from radiation exposure

This professor says:

The concern is that not any one person eating one tuna is gonna have a problem, but that over large numbers of people, the small increase in radiation will produce a small increase in cancer risks.

Not all fish or sea-food products (e.g. kelp) would be involved - only those with increased bio-accumulation of radioactive particles.

Some articles state that fish caught near Fukushima (from var. time periods) is not safe. Other statements say that pacific ocean fish "pose no risk to people" without citing levels of potential exposure in relationship to safety regulations.

How does a increase in risk to large numbers not impact the individuals risk? Are there factors that will increase the risk to an individual eating these fish?

New Alexandria
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  • I feel like all of you people have tried to simplify the question without providing justification for the simplifications. This is likely a complex matter that affects very specific populations, while others are *unlikely to experience dangers that fall outside of regulations* – New Alexandria Dec 03 '13 at 21:46
  • The issue is that you haven't presented us a notable claim for us to examine. You're just asking stuff. You need to isolate a claim that somebody has made. Quote it, and link to its source. Then, we'll examine it. –  Dec 03 '13 at 21:47
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    @NewAlexandria -Skeptics SE is not for requesting original research. We investigate claims of fact made by notable people. The professor in the first claim was a perfect choice which is why I limited the question to that link. Your second link basically answers the question you are asking. I do not know what you are expecting from here but I suspect it is off topic. You could problably make 20 different questions just off of the information in your links. – Chad Dec 03 '13 at 21:51
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    @NewAlexandria Thanks for including the quote. That is the only part of this question that is on topic. This question would be improved by removing the rest of the question. But, since you reverted my edit last time, I'll leave that to you. –  Dec 03 '13 at 21:54
  • @Chad I see from your statement that Skeptics.SE is not trying to discover new things, only instead guide peoples' thinking to what is currently published. The aim of this question is to reveal *more* information, which could save lives — which, in context to this question, *runs counter* to the objective of this site. – New Alexandria Dec 03 '13 at 21:56
  • @NewAlexandria - Yes we have suggested many times this SE would be more aptly named [Citation Required](http://meta.skeptics.stackexchange.com/q/1438/3126)... You are looking for someone to help you perform some original research which is off topic for the site. Sorry – Chad Dec 03 '13 at 21:59
  • And to think that the Skepticism movement ostensibly-began to protect people from the dangers of *deluded* and *incomplete* models of the real world! You can go find a citation for that; ***I'm going to go try to help people.*** – New Alexandria Dec 03 '13 at 22:05
  • @NewAlexandria - I have modified the question to bring it more on topic. You can not ask for the information specifically... that does not prevent people answering the question to finding information that you have noted is of interest to you. This is probably the closest we can get to being able to ask the question that you want. Sadly the Skeptics name creates problems for people, like you, who want to ask a legitimately skeptical question that does not fit the mold of this SE. – Chad Dec 03 '13 at 22:08
  • @Chad I made the quote more accurate. I think that matches what you trying to do with your edit. –  Dec 03 '13 at 22:11
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    "over large numbers of people, the small increase in radiation will produce a small increase in cancer risks." The [Linear No Threshold](http://en.wikipedia.org/wiki/Linear_no-threshold_model) model says this is true, but its also true (and a larger-but-still-microscopic risk) for bananas, brazil nuts, and indeed the C14 present in all sugars. Doing the maths allows one to make silly predictions [like the ones here](http://www.straight.com/life/497646/fish-data-belie-japans-claims-fukushima). Note for comparison, alcohol causes about 20,000 annual cancer deaths in the USA. – Ken Y-N Dec 04 '13 at 00:15
  • @KenY-N that is more than the number of firearms-related homicides, and so we should care more about alcohol-related cancer, by-the-numbers. Right? – New Alexandria Dec 04 '13 at 00:38
  • @NewAlexandria: Please keep an eye on the tone of the comments, and keep them friendly. It is easy for nuance to be lost in short texts. I can see the edit history has gone back and forth here, but I do see people trying to help by bringing the question into scope to stop it from being closed. – Oddthinking Dec 04 '13 at 01:05
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    @KenY-N: Why don't you expand that comment into a real answer? (You should include a better explanation of why you think that prediction is silly, because you seem to beg the question there.) – Oddthinking Dec 04 '13 at 01:10
  • Asks for original opinion / research and therefore belongs on another board. – denten Dec 07 '13 at 07:42

1 Answers1

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I'll skip the "seems plausible" conjecture, and focus on the professor who says:

The concern is that not any one person eating one tuna is gonna have a problem, but that over large numbers of people, the small increase in radiation will produce a small increase in cancer risks.

If we look at the Linear No-Threshold model, what the professor says is absolutely true. There are two other main models, the Threshold model that says up to a certain level radiation is benign, and the Radiation Hormesis model that says up to a certain level radiation is actually beneficial. Thus, the LNT is obviously the more conservative of the three. As far as I am aware, the other two models are more favoured scientifically and LNT is just a compromise. Note, however, that UNSCEAR says this:

Due to the great uncertainties in risk estimates at very low doses, UNSCEAR does not recommend multiplying very low doses by large numbers of individuals to estimate numbers of radiation-induced health effects within a population exposed to incremental doses at levels equivalent to or lower than natural background levels.

This is what the professor is doing. Looking at data from east Pacific tuna presented here, we see:

In bluefin tuna caught off San Diego, the total radioactive cesium levels were 10 becquerels, only three percent above radiation levels from naturally occurring potassium-40, and far below safe-consumption levels set by the United States and Japanese governments.

I shall assume they mean 10 Bq/kg.

A single banana, by comparison, has 15 becquerels of potassium-40, or, given a 150 gramme banana, 100 Bq/kg. Therefore we are looking at less than a tenth of the effect (or indeed 40% of the 25 Bq/kg from the C14 in the sugars in a banana). However, I have seen it argued that (a) the body has evolved to handle natural radiation (now that would be a good question for here!) and (b) it bio-accumulates, unlike K40 and C14.

Therefore, I conclude that Professor Daniel Hirsch (ad hom: a politics lecturer and anti-nuclear campaigner) is correct in what he says, but he goes against the advice of UNSCEAR to produce his conclusion.

Ken Y-N
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  • And for god's sake, put that banana down before you doom everyone in the house! – Shadur Dec 04 '13 at 12:38
  • **This does not answer the question**, which regards at-risk populations. By skipping the *main part of the question*, you have answered someone else's question - not this one. ***I consider your answer a comment, or an answer to a different question.*** – New Alexandria Dec 04 '13 at 14:34
  • To be extra-clear, the professor that's being quoted was not speaking about at-risk populations. – New Alexandria Dec 04 '13 at 14:35
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    @NewAlexandria If the referenced quote isn't about at-risk populations, then the question isn't either: the subject of the question and the answer is the quoted reference. To ask instead about at-risk populations, you must reference a claim about about at-risk populations: a reference which could say either that they are, or that they are not, at risk from such increases. [FAQ: Must all questions be notable?](http://meta.skeptics.stackexchange.com/q/864/2703) – ChrisW Dec 04 '13 at 14:54
  • @Shadur - Its not going to doom everyone just 1 in 500M just hope that 1 is not in your house :p – Chad Dec 04 '13 at 15:02
  • @NewAlexandria - then please supply a notable claim saying that at-risk people are susceptible to the effects of below-background radiation. For someone on chemotherapy, for example, there already is a known minor cancer risk (>1/1000 according to Wikipedia), from these significantly large doses; what mechanism might cause 10 Bq/kg to significantly add to this risk? – Ken Y-N Dec 04 '13 at 23:43
  • @Chad bananas are dangerous weapons of mass flatulus explosions... good answer, except I'd say Ken's too kind to the professor's use of incorrect models with suspect data to produce alarmist results and then publish them without proper scientific protocol for political gain. – jwenting Dec 05 '13 at 06:34