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BrokenImmersion t1_j2f57j4 wrote

Reply to comment by Dubanx in If fish accumulate mercury in the more toxic, methylmercury form, is it toxic to them? by XComhghall

But being larger creatures does that mean we can reasonably take in a larger dose of mercury and be relatively okay from it?

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BioTechproject t1_j2f631l wrote

yes, but that's countered by living long meaning you can take up way more, than an organism that e.g. is larger but lives shorter.

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BrokenImmersion t1_j2f68t1 wrote

Ah so we can ingest more but because it sticks around so long and we live so long it doesn't really matter?

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Syzygy_Stardust t1_j2ft7f0 wrote

The opposite. Because we live so long, we have more chances to absorb mercury than short-lived animals, which is worse for us. Obviously living longer is itself usually a preferred state, but it does cause situations like this where health issues arise over long periods of time.

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BioTechproject t1_j2f75k2 wrote

I wouldn't say it doesn't matter. It is still a significant factor.

For example, a similar concept applies when prescribing medication. Overweight people have larger volumes and thus, depending on meds, need more to reach the same effect.

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VoilaVoilaWashington t1_j2fhenh wrote

Yes, but it also means we need to eat more.

Take two animals with identical metabolisms, one's 10kg and one's 100kg.

If both eat 0.1mg per day of a toxin, then yeah, the bigger creature will do better.

But if the food contains 0.1 mg/kg of food, and the big creature needs to eat 10x more food to survive, then it balances out.

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sighthoundman t1_j2fmsxq wrote

Sort of. Part of the reason that antibiotics work so well is that the amount to kill a bacterium is way smaller than the amount to kill a person.

The problem with mercury (and heavy metals in general) is that there's no way to flush them from the body.* We don't usually worry about salt buildup, because our bodies naturally dilute the salt and flush it out the kidneys. Things like that don't happen with the heavy metals.

* Yes, chelation therapy exists as a treatment for heavy metal poisoning. There are pretty strict guidelines, mostly because one of the side effects of chelation therapy can be death. "The therapy was a success but the patient died."

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Dubanx t1_j2frugo wrote

While large animals eat more, they also eat foods that themselves have higher concentrations of mercury.

Krill eat mercury, have tiny amounts of mercury. Small fish eats many krill, bioaccumulate all the mercury from the krill. Small fish has relatively much more mercury in them than krill.

Medium fish eats many small fish. Medium fish bioaccumulates mercury from many small fish, it has even higher concentrations of mercury.

Large fish eats medium fish.

We eat the large fish, which has A LOT of mercury in it. Many times more mercury than the small animals do.

So it's not just the matter of we need more mercury and we eat more mercury but we tend to eat animals which themselves have relatively high levels of mercury. Then live long lives, giving said mercury a lot of time to build up.

I guess it's a bit redundant with the top of the food chain line.

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