Mercury levels in Flu shots and tuna

[rjh01]

You want to eat relatively short lived cold water fish like cod. The longer a fish lives the more mercury it accumulates, like the ancient long life Sturgeon, where the rich get their caviar from.

And also the higher up the food chain, the faster the rate mercury (and other heavy metals) accumulates. This is a good reason not to routinely eat land animals that eat meat.

 

[blutoski]

ug/lb? That's an odd unit.

It's not vapour form, so this is convenient for food product, which is sold by the pound in the US. In Canada, we usually see more along the lines of 'per 100g'.

According to the NIOSH Pocket Guide (2010) the IDLH level for mercury compounts (CAS # 7439-97-6) is 10 mg/m^3. FPPE required is skin protection; basically Modified Level D. The IDLH for mercury alkyl compoutnds is 2 mg/m^3, and requires Modified Level D with splash goggles. I don't have an MSDS on hand (which is odd, because my HAZWOPER stuff is right here). Anyway, if we're going to discuss the effects of murcury that's the stuff we should be talking about.

Makes sense.

The problem with Hg is that it's a persistant bioaccumulating toxic chemical, meaning that once it gets into you it doesn't necessarily go away. Now to get in it has to be bioavailable--and that's the part that will drive anti-vaxers into a frothing rage (they insist that mercury=mercury, meaning that even stuff which cannot possibly be used by any biological process and which is passed through the body completely should be treated as though it were poison). But once it finds a way in you're stuck with it.

Yes, this is why I distinguished between acute poisoning - which is rare - vs chronic toxic exposure. The latter is a real problem, especially in countries with significant fish in the diet.

I'm not sure we have any evidence based studies that tell us the relative safety of injecting tuna directly into the body.

I'm really just trying to pass along my experience: I think the analogy has some rhetorical weakness to skeptics confronted by an antivaxxer who is prepared.

Skeptic: "My esteemed opponent may be interested to know that there is more mercury in a can of tuna than in a vaccine."

Antivaxxer: "So... you're saying it's safe to inject tuna into children's arms?"

Skeptic: "Uh, no, that's not what I'm saying. That would be very dangerous. Don't do that."

 

[Paradox74]

Not an acute case, but the FDA and other countries are aware of risk of chronic mercury toxicity associated with eating a lot of fish.

There have been products taken off the market because they exceeded the maximum limit (in the USA that's 480ug/lb).

Having said that... some antivaxxers are aware of this argument and they do have a canned (hah! get it?) response. The first is to point out that injecting something is almost always more acute than eating it (which is true), and the second line of defense is to hand-wave and say that mercury in tuna is 'natural' and therefore not very harmful by definition.

But isn't it true that once the tuna passes through the digestive system, all of the nutrients (including all, if not then most, of the mercury) would be absorbed into the body, including the bloodstream? Wouldn't that mean that there is a strong possibility that you would ingest more mercury from that particular 6oz can of tuna versus a vaccine shot with 1 ppm of mercury?

Skeptic: "My esteemed opponent may be interested to know that there is more mercury in a can of tuna than in a vaccine."

Antivaxxer: "So... you're saying it's safe to inject tuna into children's arms?"

Skeptic: "Uh, no, that's not what I'm saying. That would be very dangerous. Don't do that."

I'll take Straw Man for $500!

 

[blutoski]

But isn't it true that once the tuna passes through the digestive system, all of the nutrients (including all, if not then most, of the mercury) would be absorbed into the body, including the bloodstream? Wouldn't that mean that there is a strong possibility that you would ingest more mercury from that particular 6oz can of tuna versus a vaccine shot with 1 ppm of mercury?

There is a reason some substances are injected intravenously, others intramuscularly, others taken orally, transdermally, inhaled, suppository - different routes of administration have different effects on the body. One route may be lethal while the other quite safe.

Alcohol is a good example. When I drink it, my body has more time to mitigate it as it transfers across the lumen and does passes through the liver. If exactly the same quantity were to be injected directly into the bloodstream, I would be much more at risk for acute alcohol poisoning. Caffeine is absorbed so much faster via suppository than orally, that this pretty much means coffee enemas are all probably about the caffeine rush.

Secondly, some components of food are not passed across the lumen, and never enter the bloodstream. The most obvious example is mucilage. Also the reason Olestra has no calories even though it is a fat. The body has to have a means to break down the bolus into particles that can be actively or passively transported across the cellular membrane, and not all particles have a mechanism, and some particles are more efficiently transported than others. ie: saturation of receptors. This is the 'bioavailability' of the substance.

Both quack hypotheses for connections between vaccination and, say, autism or other illnesses do emphasize the premise of "overwhelming" the body with an injection of a toxin that the body can probably manage orally in limited doses (the Thimerosal nuts), or never takes orally but overwhelms the immune system (the MMR nuts).

I'll take Straw Man for $500!

Well, in critical thinking circles, we try to bring attention to anything that can be called 'a bad analogy' - this is also a type of logical fallacy that skeptics need to take into account when constructing our arguments.

Over-and-above that, the important question for me (and I'm not saying it should be other people's prioirty) is 'does this particular rhetoric change minds?'

 

[Dinwar]

It's not vapour form, so this is convenient for food product, which is sold by the pound in the US. In Canada, we usually see more along the lines of 'per 100g'.

No, I get that--I was just commenting on the mixture of measurement systems. I wasn't trying to say it was wrong or anything, just that it's something that made me do a double-take.

Skeptic: "My esteemed opponent may be interested to know that there is more mercury in a can of tuna than in a vaccine."

Antivaxxer: "So... you're saying it's safe to inject tuna into children's arms?"

Skeptic: "Uh, no, that's not what I'm saying. That would be very dangerous. Don't do that."

It has some value, in that it exposes the fact that anti-vaxers use scare tactics rather than data, but you're right about the danger--people who believe pseudo-science are remarkably good at misinterpreting analogies. That's why I stick to bioavailability. No anti-vaxer has yet explained how a chemical that's (essentially) not bioavailable can cause harm.

 

[LarianLeQuella]

Over-and-above that, the important question for me (and I'm not saying it should be other people's prioirty) is 'does this particular rhetoric change minds?'

Well, considering the way they consistently ignore evidence for their dogmatic worldview, I would say that it would be difficult with a full blown anti-vaxxer.

For a concerned parent, it may mean something.

 

[blutoski]

Well, considering the way they consistently ignore evidence for their dogmatic worldview, I would say that it would be difficult with a full blown anti-vaxxer.

For a concerned parent, it may mean something.

It might. I'd love to find out. Preferably before publishing about it.

I come into skepticism with marketing experience, and one of the things that has baffled me for decades is what appears to be a disconnect between demanding proof of efficacy for, say, a medical treatment while demanding no proof of efficacy before investing in a skeptical topic 'awareness campaign'. Often at huge expense.

Particularly since there is a huge legacy of published research about persuasion and education out there, including two milennia of professional sophistry and a few hundred years of evangelical rhetoric. Persuasion is a mature profession.

Having said that... I repeat my comment above that I may simply misunderstand the goal for these projects. It may simply be a community activity, which means the point may be to galvinize those who already agree, or recruit for a particular organization. These activities do seem to do that, but I don't like that fundraising for them is often represented as outreach or education.