Well, there's two questions, right? The first is how harmful tritiated water is to begin with. It's a low-energy beta emitter and, because it mixes quickly and permanently with water, it's eliminated quickly as well. You wouldn't want to go out of your way to drink it, though.
The second question is, what is the environmental impact of dumping it in the ocean? No matter how dangerous it is, the ocean is gigantic. So you want to know: are there environmental processes that concentrate or amplify it?
Later: I had to leave before writing this last part.
Obviously, all things being equal, you'd rather TEPCO keep spending money to keep this stuff out of the ocean. But are all things equal? Is it riskier to try to contain it?
> No matter how scientifically sound the solution, "dump it all in the ocean" simply can't happen.
Headline: "State Government to dump contaminated water from nuclear plant in ocean"
Quote: "There may potentially be a risk to flora & fauna, but we don't know for sure."
That's all it takes to make the idea political suicide. I think that's obvious from a mile away, even if many of us here agree that diluting it in the ocean is likely to be environmentally and fiscally sound.
It could happen, if this had worldwide scientific consensus (Japan, China, Australia, US, Europe and Russia), and if agreed on in the UN. And if you dump this all at once in the same place, you're stupid. It could be dumped over the course of years in different places, while monitoring radiation levels in water and fish.
Normal ocean water has potassium and rubidium radionuclides that run to 11Bq/L.
At the higher level of 5MBq/L, they would need to dilute it into 3000km^3 of seawater in order to reach double background radiation levels, or a patch of the 6km deep Pacific abyssal plain that is 22km x 22km.
Tritiated water will not change the PH of the oceans. There's also a very very tiny amount of it to deal with. The scale of the 2 problems is not really comparable.
The second question is, what is the environmental impact of dumping it in the ocean? No matter how dangerous it is, the ocean is gigantic. So you want to know: are there environmental processes that concentrate or amplify it?
Later: I had to leave before writing this last part.
Obviously, all things being equal, you'd rather TEPCO keep spending money to keep this stuff out of the ocean. But are all things equal? Is it riskier to try to contain it?