That seems like an odd request. Something that is safe diluted across an entire ocean may not be safe to drink. In fact, regular seawater isn't all that great for you.

It's the released water not the seawater. That causes vomiting, delirium, and hallucinations :-)

“A Japanese official said it’s okay if you drink this water,” Chinese Foreign Ministry spokesman Zhao Lijian said at a news briefing. “Then please drink it.”

The poster you asked is not that Japanese official. They just said dumping it was not a concern. Posting someone else's claim and asking them if they're ready to "back their claim" is disingenuous.

I realize that, and I would imagine everybody else in this thread.

That was why, to try to avoid sounding disingenuous, I tried to apologize upfront for the question, and recognized and appreciated the poster qualifications.

I was trying to qualify what safe means in this context. A bit like when talking for example to an aircraft manufacturer CEO, for example as in:

1) "This new airplane model is perfectly safe to fly" ...type of safe

OR

2) "This new airplane model is perfectly safe to fly, I will do a weekly trip on it with my family" ...type of safe

This argument is not useful. #1 and #2 differ based on the disposition of the CEO. A stupid, or not good at thinking about statistics and risks, CEO will happily get on a plane to get a bigger bonus, even if it's not that safe.

Your method of asking was very confrontational, even if you did start it politely. You challenged them to "back your claim" which wasn't their claim.

You could have asked something like "do you agree with the Japanese claim that the water is safe to drink? Would you be willing to drink it?"

Reading it again, I can see how it could seem that way, although none of that was on my mind.

I have a tritium vial on my keychain. 5 mm of air is sufficient to block it. It’s pretty harmless stuff in the level of dilution being proposed.

I mean, yes. But there’s no 5mm of air between tritium you drink and your stomach.

You're probably thinking of getting a speck of a radioactive metal (like Uranium or Plutonium) in your lungs. That gets stuck there, the body has no mechanisms to eliminate it, and it will keep emitting gamma rays all your life.

Tritium is very different. It is an isotope of Hydrogen, and a water molecule containing one atom of Tritium is fairly indistinguishable from any other water molecule. The most important thing is that it has no reason to stick to any other Tritium from that glass that you drank. It will spread throughout your body. Like all other water molecules, it will probably be out of your body in a mater of days. Tritium's half life is 12 years, so the vast, super vast majority of all the Tritium you'd drink with that glass of water will be long gone before it has a chance to decay.

But even if some of these atoms decay, their decay is a beta particle (an electron, and if you really care one antineutrino as well, although that antineutrino will probably travel through a few galaxies before it interacts with anything). The beta particle is not very damaging (compare that with the gamma rays emitted by Plutonium). For sure a single one is not damaging at all. Now, in contrast with the speck of the radioactive metal above, this beta particle will not be followed by others like it, because the Tritium that emitted it doesn't have any other Tritiums next to it.

Hmm, if people were worried about ingestion I was certain it had to be alpha particles. I stand corrected.

I’m not sure how much the half life matters a lot if you ingest a lot. To be fair, kinda unlikely from drinking water, but might be if a fish has been gathering Tritium it’s whole life (but then, it’s probably already doing that now for much larger quantities).

Either way, I suppose the 3 X-rays I had today completely obviate any relevance of the tritium.

> might be if a fish has been gathering Tritium it’s whole life

Unless fish have some mechanism for selectively keeping tritium (which might be very useful) or don't replace their water, there's no way for a fish to "[gather] Tritium its whole life".

> But there’s no 5mm of air between tritium you drink and your stomach.

Correct; it's in liquid, which blocks its radiation even more effectively.

The mucous layer in the stomach and intestines will stop it cold. It can't even get past the layer of dead cells that make up our skin.

Notwithstanding your qualifications, this reply is a bit off the mark. The tritium in that vial is indeed no danger, the beta decay of the tritium won't get past the vial itself. Tritium ingested is indeed a danger, however, because once in the body, the water molecules that carry the tritium can and will go anywhere in the body. Most will be excreted in the urine, but some will some will end up in cell nuclei, where their low energy beta decay can and does do real damage to DNA.

Note that I am not arguing that the tritium releases proposed in Japan are dangerous. They are far below any theshold for risk that should concern us. But that's because the concentration is so low, not because ingested tritiated water isn't potentially dangerous.

Thank you. This was the type of answer I was looking for.

I'd probably rather drink this than most brackish water out there.

I am quite sure there are more naturally occurring reservoirs of water that is strictly more lethal; also non-diluted.

After it's been diluted in the planet's oceans, I'm sure he wouldn't mind drinking it.